Article

Sentence comprehension and working memory limitation in aphasia: A dissociation between semantic-syntactic and phonological reactivation

August 2003
Brain and Language 86(1):23-39

August 2003
86(1):23-39

DOI:10.1016/S0093-934X(02)00530-8

Source
PubMed

Authors:

Naama Friedmann

Tel Aviv University

Aviah Gvion

Ono Academic College Reuth Tel Aviv Rehabilitation Hospital Israel

The relation between working memory (WM) limitation and sentence comprehension was assessed in Hebrew-speaking aphasics, three conduction aphasics and three agrammatics. The study compared sentences that required different types of reactivation-syntactic-semantic reactivation, in relative clauses, and word form/phonological reactivation, in sentences with reanalysis of lexical ambiguity. The effect of phonological memory load, manipulated by number of words intervening between the activation and the reactivation, on comprehension of the two sentence types was examined. The findings were that agrammatic aphasics failed in the comprehension of object relatives but not on subject relatives irrespective of their antecedent-gap distance. Conduction aphasics, on the other hand, who showed severe WM limitation, comprehended well all types of relative clauses and were unaffected by antecedent-gap distance. The conduction aphasics failed to understand the sentences that required phonological reactivation when the phonological distance was long. These results suggest that the type of reactivation required by the sentence, as well as the type of memory overload are crucial in determining the effect of WM limitation on sentence comprehension.

Effect of Distance between Marker Agreement Dependencies on Sentence Comprehension in Persons with Aphasia

Article

Full-text available

Sep 2020

Background: Rules and regularities are embedded in all the language structures. Extracting these helps in speech-language acquisition and processing. Sentence processing relies on transitional probability of the dependencies and its distance which are present within the sentence. Aim: To investigate the effect of distance between marker agreement dependencies on sentence comprehension in Persons with Aphasia (PWA) and Neuro- Typical Individuals (NTI). Methods: Ten PWA and Ten NTI were recruited for the study. Participants whose native language was Kannada (a South Indian Language) and received formal education of minimum 10th grade were selected. Materials: A total of 60 Kannada sentences were used and grouped into three categories i.e., short sentence (had short distance between dependencies) (SSD); Longer sentences (had long distance between dependencies) (LLD) and longer sentences (had short distance between dependencies) (LSD). The agreement markers in the sentence were manipulated w.r.t distance among them and grouped it as adjacent (short distance) and non-adjacent (long distance) type of sentences. Procedure: The participants were instructed to read the sentence and judge whether it is grammatically correct or not by pressing the key corresponding to 'yes' or 'no' on the keyboard. In addition, modified N-back task was administered. Results and discussion: Accuracy and reaction time measures were derived for each sentence types. NTI showed better performance than PWA in sentence judgment task. Both the groups, performed poorly on LSD type of sentence when compared to other sentence types. LSD type was more complex due to the syntactic demands placed by the antecedent preposition, pronoun and adverb placed nearer to the verb and also longer distance between subject agreement to the verb.

Statistical Learning in Persons with Aphasia: A Critical Review of Literature

Article

Oct 2020

Language abilities, not cognitive control, predict language mixing behavior in bilingual speakers with aphasia

Article

Jul 2023
J COMMUN DISORD

Purpose: Language Mixing (LM) occurs among neurotypical bilinguals as well as among bilingual persons with aphasia (BiPWAs). The current study aimed to investigate whether LM in BiPWAs stems from a linguistic impairment, an impairment in cognitive control, or both. Method: Twenty Russian-Hebrew-speaking BiPWAs were split into two groups based on aphasia severity (Severe/Moderate vs. Mild). Frequencies and patterns of LM in narrative production by BiPWAs in L1-Russian and in L2-Hebrew were analyzed. To investigate the underlying mechanisms of LM, all participants completed linguistic background questionnaires, the Bilingual Aphasia Test (BAT) in both languages, and a battery of 10 cognitive tests. Results: The results indicated an effect of aphasia severity and an effect of language. Higher LM frequency was observed in BiPWAs with severe/moderate aphasia symptoms as compared to BiPWAs with mild symptoms. In both groups, higher LM frequency was observed in L2-Hebrew narratives, the weaker post-stroke language for most participants in the sample. The results also showed qualitative LM differences in L1-Russsian and L2-Hebrew contexts. In L1-Russian narratives, BiPWAs mainly switched to L2-Hebrew nouns, while in L2-Hebrew narratives, they mainly inserted L1-Russian discourse markers and function words. Conclusions: Linguistic factors such as pre- and post-stroke self-rated language proficiency and level of language impairment due to aphasia were found to predict LM frequency in L1-Russian and in L2-Hebrew. Cognitive abilities did not predict LM frequency. Based on our findings, we suggest that LM behavior in BiPWAs might be primarily related to language skills in L1 and L2, rather than to cognitive control impairments.

Semantic Feature Analysis (SFA) treatment in L1 and L2 in bilingual aphasia: Effects of cognitive and language factors

Article

Jun 2023

Effect of Working Memory Load and Typicality on Semantic Processing in Aphasia

Article

Jun 2021

Purpose This study evaluated the effects of a linguistic characteristic, typicality, and a processing variable, working memory on the abilities of people with aphasia (PWA) and neurologically intact adults to process semantic representations. This was accomplished using a newly developed assessment task, the Category Typicality Test, which was created for the Temple Assessment of Language and Short-Term Memory in Aphasia. Method A post hoc quasi-experimental design was used. Participants included 27 PWA and 14 neurologically intact adults who completed the picture and word versions of the Category Typicality Test, which required them to determine if two items are in the same category. Memory load was altered by increasing the number of items to be compared, and the typicality of items was altered to increase linguistic complexity. Results A four-way mixed analysis of covariance was conducted. There was a significant interaction between working memory load and category typicality with performance accuracy decreasing as working memory load increased and category typicality decreased. There was also a significant interaction for typicality and stimuli with better performance in the picture condition and a significant interaction for working memory and group with lower performance accuracy for PWA. Post hoc pairwise comparisons revealed differences between memory load, typicality, stimuli conditions, and group. PWA also showed greater magnitude of change than neurologically intact adults when comparing high and low working memory load conditions, but not typicality conditions. Discussion Increasing working memory load had the most substantial impact on the accuracy of category judgments in PWA, but the interaction between increased working memory load and decreased category typicality of items to be compared resulted in reduced accuracy in both groups. These findings suggest that manipulation of processing and linguistic variables in assessment will provide insight into the nature of linguistic breakdown in aphasia. Supplemental Material https://doi.org/10.23641/asha.14781996

Working memory training in post-stroke aphasia: Near and far transfer effects

Article

Jan 2021
J COMMUN DISORD

Purpose Individuals with aphasia (IWA) show various impairments in speech, language, and cognitive functions. Working memory (WM), a cognitive system that functions to hold and manipulate information in support of complex, goal-directed behaviors, is one of the impaired cognitive domains in aphasia. The present study intended to examine the effects of a WM training program on both memory and language performance in IWA. Method This quasi-experimental study with an active control group was performed on 25 people with mild or moderate Broca’s aphasia aged 29-61 years resulting from left hemisphere damage following ischemic stroke. Participants were assigned into two groups, including a training group (n = 13) and a control group (n = 12). The treatment and control groups received WM training and routine speech therapy, respectively. Two separate lists of WM tests, including one list for both pre-training assessment and training program and a second list for the post-training assessment, were used in this study. Results The treatment group showed significant improvements in both trained and non-trained WM tasks (near transfer effect) and language performance (far transfer effect) compared to the control group. Conclusion Given the good generalizability of the WM training program on both WM and language performance, WM training is suggested as part of the rehabilitation program in aphasia.

Transfer effects after working memory training in post-stroke aphasia

Thesis

Full-text available

Nov 2018

Lilla Zakariás

Background: Individuals with aphasia after stroke (IWA) often present with working memory (WM) deficits. Research investigating the relationship between WM and language abilities has led to the promising hypothesis that treatments of WM could lead to improvements in language, a phenomenon known as transfer. Although recent treatment protocols have been successful in improving WM, the evidence to date is scarce and the extent to which improvements in trained tasks of WM transfer to untrained memory tasks, spoken sentence comprehension, and functional communication is yet poorly understood. Aims: We aimed at (a) investigating whether WM can be improved through an adaptive n-back training in IWA (Study 1–3); (b) testing whether WM training leads to near transfer to unpracticed WM tasks (Study 1–3), and far transfer to spoken sentence comprehension (Study 1–3), functional communication (Study 2–3), and memory in daily life in IWA (Study 2–3); and (c) evaluating the methodological quality of existing WM treatments in IWA (Study 3). To address these goals, we conducted two empirical studies – a case-controls study with Hungarian speaking IWA (Study 1) and a multiple baseline study with German speaking IWA (Study 2) – and a systematic review (Study 3). Methods: In Study 1 and 2 participants with chronic, post-stroke aphasia performed an adaptive, computerized n-back training. ‘Adaptivity’ was implemented by adjusting the tasks’ difficulty level according to the participants’ performance, ensuring that they always practiced at an optimal level of difficulty. To assess the specificity of transfer effects and to better understand the underlying mechanisms of transfer on spoken sentence comprehension, we included an outcome measure testing specific syntactic structures that have been proposed to involve WM processes (e.g., non-canonical structures with varying complexity). Results: We detected a mixed pattern of training and transfer effects across individuals: five participants out of six significantly improved in the n-back training. Our most important finding is that all six participants improved significantly in spoken sentence comprehension (i.e., far transfer effects). In addition, we also found far transfer to functional communication (in two participants out of three in Study 2) and everyday memory functioning (in all three participants in Study 2), and near transfer to unpracticed n-back tasks (in four participants out of six). Pooled data analysis of Study 1 and 2 showed a significant negative relationship between initial spoken sentence comprehension and the amount of improvement in this ability, suggesting that the more severe the participants’ spoken sentence comprehension deficit was at the beginning of training, the more they improved after training. Taken together, we detected both near far and transfer effects in our studies, but the effects varied across participants. The systematic review evaluating the methodological quality of existing WM treatments in stroke IWA (Study 3) showed poor internal and external validity across the included 17 studies. Poor internal validity was mainly due to use of inappropriate design, lack of randomization of study phases, lack of blinding of participants and/or assessors, and insufficient sampling. Low external validity was mainly related to incomplete information on the setting, lack of use of appropriate analysis or justification for the suitability of the analysis procedure used, and lack of replication across participants and/or behaviors. Results in terms of WM, spoken sentence comprehension, and reading are promising, but further studies with more rigorous methodology and stronger experimental control are needed to determine the beneficial effects of WM intervention. Conclusions: Results of the empirical studies suggest that WM can be improved with a computerized and adaptive WM training, and improvements can lead to transfer effects to spoken sentence comprehension and functional communication in some individuals with chronic post-stroke aphasia. The fact that improvements were not specific to certain syntactic structures (i.e., non-canonical complex sentences) in spoken sentence comprehension suggests that WM is not involved in the online, automatic processing of syntactic information (i.e., parsing and interpretation), but plays a more general role in the later stage of spoken sentence comprehension (i.e., post-interpretive comprehension). The individual differences in treatment outcomes call for future research to clarify how far these results are generalizable to the population level of IWA. Future studies are needed to identify a few mechanisms that may generalize to at least a subpopulation of IWA as well as to investigate baseline non-linguistic cognitive and language abilities that may play a role in transfer effects and the maintenance of such effects. These may require larger yet homogenous samples.

The Meeting Point: Where Language Productionand Working Memory Share Resources

Article

Full-text available

Feb 2019
J PSYCHOLINGUIST RES

The interaction between working memory and language processing is widely dis-cussed in cognitive research. However, those studies often explore the relationship betweenlanguage comprehension and working memory (WM). The role of WM is rarely consideredin language production, despite some evidence suggesting a relationship between the twocognitive systems. This study attempts to ﬁll that gap by using a complex span task duringlanguage production. We make our predictions based on the reorganization of elementaryfunctions neurocognitive model, a usage based theory about grammatical status, and lan-guage production models. In accordance with these theories, we expect an overlap betweenlanguage production and WM at one or more levels of language planning. Our results showthat WM is involved at the phonological encoding level of language production and thatadding WM load facilitates language production, which leads us to suggest that an extratask-speciﬁc storage is being created while the task is performed.

QUESTION PRODUCTION IN ITALIAN-SPEAKING PWAGR

Article

May 2024

Nevena Klobučar

This paper presents the results of an elicitation task run with Italian-speaking people with agrammatic aphasia (PWAgr). Linguistic theories of aphasia have analysed the production of PWAgr as stemming either from a deterioration of grammatical knowledge or a limitation of extra-linguistic capacities which affect language. Among the former, the Tree Pruning Hypothesis (Friedmann and Grodzinsky, 1997) relates the height of the projections involved in the production of a structure with the chances of it being produced: the stronger the impairment in the speaker, the less likely they are to produce a structure involving higher nodes. Alternatively, syntactic knowledge may be preserved but its use is compromised by Working Memory (WM) limitations (e.g., Miyake et al., 1994; Jakubowicz, 2005). The two approaches make different predictions with respect to question production in Italian: according to the TPH, the production rates of yes/no-questions and who-questions should be comparable in moderate and mild aphasia. Why-questions involve a higher node and should thus not be available. Under a WM-limitation approach, the production rates of why-questions and yes/no-questions should be comparable and higher than those of who-questions. To determine which, if any, of the two approaches makes the correct predictions, three adult Italian speakers diagnosed with Broca’s aphasia and one with anomia performed an elicitation task targeting these three types of structures. Overall, yes/no-questions were the most frequent structures to be produced. The lack of who-questions, as opposed to the production of yes/no-questions, can be accounted for only if derivational complexity is taken into account, but the scarcity of why-questions suggests that the height of the nodes involved may play a role as well.

Unraveling the Thread of Aphasia Rehabilitation: A Translational Cognitive Perspective

Article

Full-text available

Oct 2023

Translational neuroscience is a multidisciplinary field that aims to bridge the gap between basic science and clinical practice. Regarding aphasia rehabilitation, there are still several unresolved issues related to the neural mechanisms that optimize language treatment. Although there are studies providing indications toward a translational approach to the remediation of acquired language disorders, the incorporation of fundamental neuroplasticity principles into this field is still in progress. From that aspect, in this narrative review, we discuss some key neuroplasticity principles, which have been elucidated through animal studies and which could eventually be applied in the context of aphasia treatment. This translational approach could be further strengthened by the implementation of intervention strategies that incorporate the idea that language is supported by domain-general mechanisms, which highlights the impact of non-linguistic factors in post-stroke language recovery. Here, we highlight that translational research in aphasia has the potential to advance our knowledge of brain–language relationships. We further argue that advances in this field could lead to improvement in the remediation of acquired language disturbances by remodeling the rationale of aphasia–therapy approaches. Arguably, the complex anatomy and phenomenology of aphasia dictate the need for a multidisciplinary approach with one of its main pillars being translational research.

Friedmann, N., & Gvion, A. (2012). Intervention and Locality in agrammatic aphasia. In the internet celebration for Luigi Rizzi’s 60th birthday‎ (pp. 1-13). Siena, Italy: CISCL Working Papers.

Article

Jul 2023

The role of category ambiguity in normal and impaired lexical processing: can you paint without the paint?

Article

Full-text available

May 2023
FRONT HUM NEUROSCI

Introduction Many words are categorially ambiguous and can be used as a verb (to paint) or as a noun (the paint) due to the presence of unpronounced morphology or “zero morphology”. On this account, the verb “paint” is derived from the noun “paint” through the addition of a silent category-changing morpheme. Past studies have uncovered the syntactic and semantic properties of these categorially ambiguous words, but no research has been conducted on how people process them during normal or impaired lexical processing. Are these two different uses of “paint” processed in the same way? Does this morphosyntactic structure have an effect on online sentence processing? Methods This study presents two experiments that investigate the effect of morphosyntactic complexity in categorially ambiguous words presented in isolation (experiment 1) and in a sentential context (experiment 2). The first experiment tested the ability to process categorially unambiguous and ambiguous nouns and verbs in 30 healthy older adults and 12 individuals with aphasia, using a forced choice phrasal-completion task, in which individuals choose whether the or to is most compatible with target words. Results Healthy controls and individuals with fluent aphasia all showed: (1) a bias toward the base category in selection rates for the and to, where the was selected more frequently for words identified to be base nouns, and to was selected more frequently for base verbs, and (2) longer reaction times for ambiguous (over unambiguous) words. However, individuals with non-fluent agrammatic aphasia showed a base-category effect only for nouns, with chance performance for verbs. The second experiment, using an eye-tracking while reading paradigm with 56 young healthy adults, showed a reading time slowdown for derived forms (to paint) compared to their base-category counterparts (the paint) in sentence contexts. Discussion These findings suggest that categorially ambiguous words likely share a common root, and are related by zero-derivation, and that impaired access to the base-category (i.e., verbs like to visit) precludes associated morphological processes and therefore the retrieval of the derived-category (i.e., nouns like the visit) in non-fluent agrammatic aphasia. This study provides insights into the theory of zero morphology, and the principles that need to be accounted for in models of the lexicon.

Investigating sentence processing and working memory in patients with mild Alzheimer and elderly people

Article

Full-text available

Nov 2022
PLOS ONE

Introduction: Linguistic disorders are one of the common problems in Alzheimer's disease, which in recent years has been considered as one of the key parameters in the diagnosis of Alzheimer (AD). Given that changes in sentence processing and working memory and the relationship between these two activities may be a diagnostic parameter in the early and preclinical stages of AD, the present study examines the comprehension and production of sentences and working memory in AD patients and healthy aged people. Methods: Twenty-five people with mild Alzheimer's and 25 healthy elderly people participated in the study. In this study, we used the digit span to evaluate working memory. Syntactic priming and sentence completion tasks in canonical and non-canonical conditions were used for evaluating sentence production. We administered sentence picture matching and cross-modal naming tasks to assess sentence comprehension. Results: The results of the present study revealed that healthy elderly people and patients with mild Alzheimer's disease have a significant difference in comprehension of relative clause sentences (P <0.05). There was no significant difference between the two groups in comprehension of simple active, simple active with noun phrase and passive sentences (P> 0.05). They had a significant difference in auditory and visual reaction time (P <0.05). Also there was a significant difference between the two groups in syntactic priming and sentence completion tasks. However, in non-canonical condition of sentence completion, the difference between the two groups was not significant (P> 0.05). Conclusion: The results of the present study showed that the mean scores related to comprehension, production and working memory in people with mild Alzheimer's were lower than healthy aged people, which indicate sentence processing problems at this level of the disease. People with Alzheimer have difficulty comprehending and producing complex syntactic structures and have poorer performance in tasks that required more memory demands. It seems that the processing problems of these people are due to both working memory and language problems, which are not separate from each other and both are involved in.

Short-term memory and sentence comprehension in Catalan aphasia

Article

Full-text available

Oct 2022

The main goal of the present study is to investigate visual and verbal short-term memory side to side with sentence comprehension in Catalan-speaking subjects with aphasia in comparison with subjects without brain damage. We aim to examine whether there are any significant correlations between their performance on short-term memory and comprehension tasks in order to evaluate the hypothesis that linguistic and memory deficits in aphasia are the result of a dysfunction of a common mechanism, usually short-term memory. Eigthy-four control subjects and twelve individuals suffering from different types of aphasia were assessed using the Catalan version of the Comprehensive Aphasia Test (CAT-CAT), which includes one recognition task and two digit and word span tests to evaluate visual and verbal short-term memory, respectively, as well as a sentence-to-picture comprehension task. The results showed that the performance of subjects with aphasia was significantly low on all tasks. Yet, the logistic regression analysis revealed that the magnitude of the differences between the control and experimental group varied across subtests, and that visual short-term memory was better preserved than verbal memory. The results also showed that there were no significant correlations between memory and language comprehension, which rules out the hypothesis that the deficits observed are due to a common underlying mechanism. Individual variation was also observed, specially on memory subtests, which suggest that memory impairments cannot explain the comprehension deficit in aphasia.

The Unfolding of Cognitive Effort During Sentence Processing: Pupillometric Evidence From People With and Without Aphasia

Article

Full-text available

Dec 2021

Purpose Arousal and cognitive effort are relevant yet often overlooked components of attention during language processing. Pupillometry can be used to provide a psychophysiological index of arousal and cognitive effort. Given that much is unknown regarding the relationship between cognition and language deficits seen in people with aphasia (PWA), pupillometry may be uniquely suited to explore those relationships. The purpose of this study was to examine arousal and the time course of the allocation of cognitive effort related to sentence processing in people with and without aphasia. Method Nineteen PWA and age- and education-matched control participants listened to relatively easy (subject-relative) and relatively difficult (object-relative) sentences and were required to answer occasional comprehension questions. Tonic and phasic pupillary responses were used to index arousal and the unfolding of cognitive effort, respectively, while sentences were processed. Group differences in tonic and phasic responses were examined. Results Group differences were observed for both tonic and phasic responses. PWA exhibited greater overall arousal throughout the task compared with controls, as evidenced by larger tonic pupil responses. Controls exhibited more effort (greater phasic responses) for difficult compared with easy sentences; PWA did not. Group differences in phasic responses were apparent during end-of-sentence and postsentence time windows. Conclusions Results indicate that the attentional state of PWA in this study was not consistently supportive of adequate task engagement. PWA in our sample may have relatively limited attentional capacity or may have challenges with allocating existing capacity in ways that support adequate task engagement and performance. This work adds to the body of evidence supporting the validity of pupillometric tasks for the study of aphasia and contributes to a better understanding of the nature of language deficits in aphasia. Supplemental Material https://doi.org/10.23641/asha.16959376

Effects of Repeated Exposure to Synthetic and Digitized Natural Speech by Individuals With Aphasia

Article

Jun 2021

Purpose Technological supports provide multimodal presentation of text, which may increase understandability of written materials by people with aphasia (PWA). Extant literature reveals that digitized natural speech and synthetic computer-generated speech within these supports are comprehensible by PWA at discrete time points; however, understandability following repeated exposure is unexplored. This pilot study evaluated understanding of, and preference regarding, synthetic and digitized natural speech during and following repeated exposures by PWA. Method This multiple–case-study project included four adults with aphasia. Participants independently completed various listening tasks in a single digitized natural speech condition and one of two synthetic speech conditions across a 2-week period. Participants completed sessions to evaluate maintenance effects and generalization to novel stimuli and an untrained synthetic voice condition 1 week and 1 month following daily practice. Results Study participants demonstrated understandability evident by at- or near-ceiling performance during baseline, practice, and follow-up sessions in the digitized natural condition and one synthetic speech condition. Individuals with mild aphasia achieved relatively consistent performance during independent practice, whereas performance of individuals with moderate aphasia fluctuated in both conditions. All four participants demonstrated variable understanding during generalization and maintenance tasks at follow-up time points. Participants most frequently indicated preference for digitized natural speech over either synthetic speech condition. Conclusions Findings hold important clinical implications when considering feasibility of utilizing these speech forms as compensatory strategies for PWA. Further research is needed to more fully understand the effects of repeated exposure to synthetic speech on comprehension among PWA.

When Hearing Does Not Mean Understanding: On the Neural Processing of Syntactically Complex Sentences by Listeners With Hearing Loss

Article

Jan 2021
J SPEECH LANG HEAR R

Purpose Adults with mild-to-moderate age-related hearing loss typically exhibit issues with speech understanding, but their processing of syntactically complex sentences is not well understood. We test the hypothesis that listeners with hearing loss' difficulties with comprehension and processing of syntactically complex sentences are due to the processing of degraded input interfering with the successful processing of complex sentences. Method We performed a neuroimaging study with a sentence comprehension task, varying sentence complexity (through subject–object order and verb–arguments order) and cognitive demands (presence or absence of a secondary task) within subjects. Groups of older subjects with hearing loss (n = 20) and age-matched normal-hearing controls (n = 20) were tested. Results The comprehension data show effects of syntactic complexity and hearing ability, with normal-hearing controls outperforming listeners with hearing loss, seemingly more so on syntactically complex sentences. The secondary task did not influence off-line comprehension. The imaging data show effects of group, sentence complexity, and task, with listeners with hearing loss showing decreased activation in typical speech processing areas, such as the inferior frontal gyrus and superior temporal gyrus. No interactions between group, sentence complexity, and task were found in the neuroimaging data. Conclusions The results suggest that listeners with hearing loss process speech differently from their normal-hearing peers, possibly due to the increased demands of processing degraded auditory input. Increased cognitive demands by means of a secondary visual shape processing task influence neural sentence processing, but no evidence was found that it does so in a different way for listeners with hearing loss and normal-hearing listeners.

Inner speech

Article

Full-text available

Sep 2020
Wiley Interdiscip Rev Cogn Sci

Peter Langland-Hassan

Inner speech travels under many aliases: the inner voice, verbal thought, thinking in words, internal verbalization, “talking in your head,” the “little voice in the head,” and so on. It is both a familiar element of first‐person experience and a psychological phenomenon whose complex cognitive components and distributed neural bases are increasingly well understood. There is evidence that inner speech plays a variety of cognitive roles, from enabling abstract thought, to supporting metacognition, memory, and executive function. One active area of controversy concerns the relation of inner speech to auditory verbal hallucinations (AVHs) in schizophrenia, with a common proposal being that sufferers of AVH misidentify their own inner speech as being generated by someone else. Recently, researchers have used artificial intelligence to translate the neural and neuromuscular signatures of inner speech into corresponding outer speech signals, laying the groundwork for a variety of new applications and interventions. This article is categorized under: • Philosophy > Foundations of Cognitive Science • Linguistics > Language in Mind and Brain • Philosophy > Consciousness • Philosophy > Psychological Capacities

Does the right hemisphere support phonological short-term memory?: A behavioral and electrophysiological examination

Preprint

Full-text available

Sep 2020

Blaine Tomkins

The extent to which the right cerebral hemisphere is involved in the perception and maintenance of sound-based verbal information is not well understood. The present study directly tested this question by having participants complete a rhyme judgment for word pairs with targets presented to either the right visual field or left visual field. To examine the time-course of phonological short-term memory within the hemispheres, rehearsal time (i.e. stimulus onset asynchrony) between probes and targets was manipulated (short, medium, long). Behavioral results showed performance declined in the left hemisphere, but improved in the right hemisphere, as rehearsal time increased. Event-related potential (ERP) results showed (N450) waveform differences between rhyming and non-rhyming trials in both hemispheres, however, waveforms on rhyming trials were more positive over the right hemisphere than the left hemisphere. Collectively, results suggest the right hemisphere is capable of perceiving and maintaining sound-based verbal information in phonological short-term memory; however, hemispheric differences arise depending on the amount of time phonological codes must be maintained and depending on auditory features of targets. Findings are discussed within the context of memory-based and decision-based cognitive models.

Inner Speech

Preprint

Full-text available

Aug 2020

Peter Langland-Hassan

Inner speech travels under many aliases: the inner voice, verbal thought, thinking in words, internal verbalization, "talking in your head," the "little voice in the head," and so on. It is both a familiar element of first-person experience and a psychological phenomenon whose complex cognitive components and distributed neural bases are increasingly well understood. There is evidence that inner speech plays a variety of cognitive roles, from enabling abstract thought, to supporting metacognition, memory, and executive function. One active area of controversy concerns the relation of inner speech to auditory verbal hallucinations in schizophrenia, with a common proposal being that sufferers of AVH misidentify their own inner speech as being generated by someone else. Recently, researchers have used artificial intelligence to translate the neural and neuromuscular signatures of inner speech into corresponding outer speech signals, laying the groundwork for a variety of new applications and interventions.

Effect of Digital Highlighting on Reading Comprehension Given Text-to-Speech Technology for People with Aphasia

Article

Jun 2020

Background Many people with aphasia have a strong desire to participate in reading activities despite persistent reading challenges. Digital reading devices and text-to-speech (TTS) technology are increasing in popularity and have the potential to help people with aphasia. Systematic investigation of modifiable TTS features provides a means of exploring this potential. Aims This study’s aim was to evaluate the effect of digital highlighting synchronised with TTS auditory and written output on reading comprehension by people with aphasia and to determine their highlighting preferences. Methods & Procedures This work was registered with clinicaltrials.gov and assigned the clinical trial registry number 01446 r prior to initiation of data collection. Twenty-five adults with aphasia read and listened to passages presented in three synchronised highlighting conditions: sentence highlighting, single word highlighting, and no highlighting. Participants answered comprehension questions, selected most and least preferred conditions, and provided feedback explaining highlighting preferences. Outcome & Results Comprehension accuracy did not vary significantly across presentation conditions, but participants preferred either single word or sentence highlighting over no highlighting. Conclusions Neither word nor sentence highlighting benefitted or hindered comprehension by people with aphasia as a group, but individual differences may occur. Clinicians should attend to personal preferences when implementing digital highlighting as a reading support strategy.

Syntactic Comprehension In Individuals With Dementia

Article

Full-text available

May 2018

Objectives: The objective of the present study was to investigate the syntactic comprehension abilities in individuals with dementia. Methods: 15 individuals with dementia and 15 typical individuals in the age range of 65-85 years with Malayalam as native language participated in the study. All the participants were assessed for their cognitive abilities using Mini Mental Status Examination and Addenbrooke's Cognitive Examination before participating in syntactic comprehension task. A total of 40 syntactically correct sentences and 40 syntactically violated sentences in Malayalam with MLU of 3-5 words were randomly presented through a laptop and the participants were instructed to listen carefully and were asked to indicate whether or not they are syntactically correct and made them to justify the sentences if the stimuli are syntactically violated. The syntactic violations in the incorrect sentences were made of altering plural markers, prepositions, polar questions and participle construction. Results & discussion: The performance of individuals with dementia was significantly poorer compared to typical group on syntactic comprehension task. Further, the differences were also observed between typical group and dementia group on all the four grammatical classes such as plural markers, prepositions, polar questions and participle construction. However, it is not very clear whether the syntactic comprehension deficits were due to linguistic impairments or due to underlying cognitive impairments such as limited working memory and information processing abilities. Conclusions: As the sentence comprehension task involves several cognitive skills such as processing, maintenance, and inhibition, these tasks become more difficult to individuals with dementia who exhibit significant deficits in working memory. More studies are required to explore the relation between syntactic comprehension and various cognitive processes in individuals with dementia.

Reducing Interference Improves the Memorization of Multiplication Facts in Case of Hypersensitivity to Interference

Article

Full-text available

Dec 2019

Hypersensitivity to interference (HYSTI) is a situation in which a person has a severe difficulty in memorizing verbal items that are similar to each other. This may result in induced dyscalculia: HYSTI was shown to correlate with a difficulty in learning the multiplication table, presumably because the multiplication table, which is memorized verbally, has much similarity between the items ("six times seven equals forty two", "six times eight equals forty eight", etc.). Here, we show causal evidence that HYSTI disrupts the memorization of multiplication facts. We report DL, a woman with HYSTI who had extremely poor knowledge of the multiplication table. To examine whether her multiplication difficulty resulted from HYSTI, we tested whether she could learn multiplication facts when interference was reduced. In a series of merely 12 short sessions over a period of 4 weeks, DL rehearsed 16 multiplication facts – four facts per week. When the 4 facts in a given week were similar to each other, DL’s learning was poor. Conversely, when the 4 facts in a given week were dissimilar from each other, DL learned them quickly and easily. The effect of similarity was observed during the training period and persisted at least two months after the end of training. These results provide the first causal evidence that HYSTI impairs the learning or retrieval of arithmetic facts. From a pedagogical perspective, our findings may call for re-considering how multiplication facts should be taught in elementary school.

Dichotic listening training following neurological injury in adults: a pilot study

Article

Full-text available

Nov 2019

Purpose: Injury to the dominant left brain hemisphere can lead to specific language deficits such as aphasia, or to the cognitive processes that support language such as attention and working memory. Language is heavily supported through the auditory modality, which is a key area of deficit in acquired language disorders, and recovery of auditory processing is a prerequisite to recovery of other language modalities. A specific auditory processing deficit that has been identified following neurologic injury is dichotic listening. Some researchers have suggested that dichotic listening can be strengthened through the use of a dichotic listening training paradigm, although the impact of this training for adults with neurological injury is unknown. The purpose of this study was to determine whether dichotic listening training improved dichotic listening performance as well as auditory comprehension in individuals with neurological injuries. Method: Five individuals with a history of acquired language deficits who met specific inclusion and exclusion criteria participated in the dichotic listening training for four to six weeks. Dichotic listening and language comprehension skills were evaluated pre- and post-training. Results: Results indicated all participants progressed through a range of dichotic listening tasks during training, and four of the five individuals improved on at least one of the dichotic listening tests post-treatment. All of the participants demonstrated some improvement in auditory processing/comprehension of complex commands. Conclusions: Dichotic listening training has the potential to positively influence dichotic listening and auditory comprehension skills in adults with neurological injury.

Ability of Sentence Comprehension according to Syntactic Complexity and Speech Rate in Patients with Dementia of Alzheimer’s Type

Article

Full-text available

Sep 2019

Hyunjoo Choi

Is Theory of Mind the basis for exhaustivity in wh-questions? Evidence from TOM impairment after right hemisphere damage

Article

Full-text available

Jul 2019
J NEUROLINGUIST

How do we know when to provide an exhaustive answer to a wh-question, which mentions all the items that satisfy the property being asked about? We explored the nature of this exhaustivity requirement by investigating whether it is grammatical or based on assessing the information needs of the person asking the question. In Experiment 1 we tested 14 individuals after right hemisphere damage who had Theory of Mind (TOM) impairment (aTOMia), which compromised their ability to assess the information needs of their interlocutor, but whose grammatical abilities were normal. The rationale was that if they provided an exhaustive answer to certain question types, the exhaustivity requirement could not depend on considering the asker's intentions. We assessed their responses to single wh-questions (e.g., Who is painting?) and multiple wh-questions (e.g., Who is painting what?) in a question-about-a-picture task compared to 5 right-hemisphere damaged patients with good TOM, and to healthy controls. The individuals with aTOMia often failed to provide exhaustive responses to the single wh-questions, but consistently produced exhaustive responses to the multiple wh-questions. This finding suggests that the source of exhaustivity in single wh-questions is based on TOM, whereas exhaustivity in multiple wh-questions is grammatically-based. Following up on a further result from Experiment 1, Experiment 2 investigated the effect of the exhaustivity requirement on attention: 6 additional participants with left visuo-spatial neglect after right hemisphere damage were tested with a similar task to assess whether their answers omitted figures on the left. Both experiments – Experiment 1 with eight neglect patients and Experiment 2 with six, revealed that the exhaustivity requirement also triggered attention shift to the left in individuals with left neglect: in their responses to single wh-questions they omitted the left figures, but in paired wh-questions they scanned the entire visual field and responded with exhaustive answers. The results provide clear evidence from neurolinguistics that exhaustivity in single wh-questions requires considerations of the asker's intentions, whereas multiple wh-questions mark the exhaustivity requirement grammatically.

Verbal memory and sentence comprehension in aphasia: A case series

Article

Jul 2019

This case series explores the relationship between verbal memory capacity and sentence comprehension in four patients with aphasia. Two sentence comprehension tasks showed that two patients, P1 and P2, had impaired syntactic comprehension, whereas P3 and P4’s sentence comprehension was intact. The memory assessment tasks showed that P1 and P2 had severely impaired short-term memory, whereas P3 and P4 performed within the normal range in the short-term memory tasks. This finding suggests an association between short-term memory deficit and sentence comprehension difficulties. P1 and P3 exhibited impaired comparable working memory deficits, suggesting a dissociation between working memory and sentence comprehension.

Effects of Written, Auditory, and Combined Modalities on Comprehension by People With Aphasia

Article

Jun 2019

Background People with aphasia experience reading challenges affecting participation in daily activities. Researchers have found combined auditory and written presentation modalities help people with aphasia comprehend contrived sentences and narratives, but less is known about the effects of combined modalities on functional, expository text comprehension. Aims This study's purpose was to examine comprehension accuracy, reviewing time, and modality preference of people with aphasia when presented with edited newspaper articles in written only, auditory only, and combined written and auditory modalities. Method and Procedure Twenty-eight adults with chronic aphasia read and/or listened to 36 passages. Following each passage, participants answered comprehension questions. Then, they ranked the modalities in accordance with preference and provided a rationale for their ranking. Outcomes and Results Comprehension accuracy was significantly better in the combined than auditory-only condition and in the written-only than auditory-only condition; the difference between combined and written-only conditions was not significant. Reviewing time differed significantly among conditions with the written-only condition taking longest and the auditory-only condition taking shortest. Most participants preferred the combined condition. Conclusions Access to combined modalities helps people with aphasia comprehend expository passages such as those found in newspapers better than auditory-only presentation. Furthermore, combined presentation decreases reviewing time from that needed for unsupported reading without compromising comprehension accuracy. Given that most participants preferred combined modality presentation, providing simultaneous auditory and written access to content through text-to-speech technology is a viable strategy when aphasia results in persistent reading challenges.

The Effect of Frontal Lobe Traumatic Brain Injury on Sentence Comprehension and Working Memory

Article

Full-text available

Sep 2018

AbstractBackground:The present study was conducted to examine the sentence comprehension and working memory in individuals withmild and moderate frontal lobe traumatic brain injury (TBI) and determine the relationship between them.Methods:Participants included 18 patients with mild TBI, 17 patients with moderate TBI and 18 non-TBI individuals. The digit spansubtest of the Wechsler intelligence scale-IV (WISC-IV) and a N-back test were used to evaluate of working memory. Moreover, thesyntactic comprehension subtest of Bilingual Aphasia Test (BAT) was used for sentence comprehension assessment.Results:The results showed that patients with mild and moderate TBI had a lower performance in comprehension of non-canonicalsentences and working memory compared to the non-TBI group. There was also a significant correlation between sentence compre-hension and working memory in the TBI groups.Conclusions:Sentence comprehension and working memory in TBI patients with frontal lobe damage are significantly lower thanthat of the non-TBI group, which may lead to some daily communication problems in these individuals. In summary, the presentstudy support for the association between working memory and sentence comprehension in participants with mild and moderatefrontal lobe traumatic brain injury.Keywords:Traumatic Brain Injury, Sentence Comprehension, Working Memory, Frontal Lobe (PDF) The Effect of Frontal Lobe Traumatic Brain Injury on Sentence Comprehension and Working Memory. Available from: https://www.researchgate.net/publication/328602678_The_Effect_of_Frontal_Lobe_Traumatic_Brain_Injury_on_Sentence_Comprehension_and_Working_Memory [accessed Nov 27 2020].

Is STM involved in sentence comprehension?

Article

Sep 2018
CORTEX

We discuss the literature concerning the role of auditory-verbal short-term memory (phonological loop) in sentence comprehension. We critically analyze data concerning patients with a selective deficit of the phonological loop, then we examine aphasic patients with deficit of auditory-verbal short-term memory and we consider the effect of STM treatment on sentence comprehension. Finally, results from imaging and TMS studies are discussed. In our opinion, data from the literature suggest that both components of the phonological loop are involved in the comprehension of some type of sentence, namely syntactically complex sentences that load on memory, such as center-embedded object relative clauses. However, it is crucial to investigate further patients with a selective STM impairment or aphasic patients, by using extensive and sophisticated experimental material.

ASD Is Not DLI: Individuals With Autism and Individuals With Syntactic DLI Show Similar Performance Level in Syntactic Tasks, but Different Error Patterns

Article

Full-text available

Apr 2018

Do individuals with autism have a developmental syntactic impairment, DLI (formerly known as SLI)? In this study we directly compared the performance of 18 individuals with Autism Spectrum Disorder (ASD) aged 9;0–18;0 years with that of 93 individuals with Syntactic-Developmental Language Impairment (SyDLI) aged 8;8–14;6 (and with 166 typically-developing children aged 5;2–18;1). We tested them using three syntactic tests assessing the comprehension and production of syntactic structures that are known to be sensitive to syntactic impairment: elicitation of subject and object relative clauses, reading and paraphrasing of object relatives, and repetition of complex syntactic structures including Wh questions, relative clauses, topicalized sentences, sentences with verb movement, sentences with A-movement, and embedded sentences. The results were consistent across the three tasks: the overall rate of correct performance on the syntactic tasks is similar for the children with ASD and those with SyDLI. However, once we look closer, they are very different. The types of errors of the ASD group differ from those of the SyDLI group—the children with ASD provide various types of pragmatically infelicitous responses that are not evinced in the SyDLI or in the age equivalent typically-developing groups. The two groups (ASD and SyDLI) also differ in the pattern of performance—the children with SyDLI show a syntactically-principled pattern of impairment, with selective difficulty in specific sentence types (such as sentences derived by movement of the object across the subject), and normal performance on other structures (such as simple sentences). In contrast, the ASD participants showed generalized low performance on the various sentence structures. Syntactic performance was far from consistent within the ASD group. Whereas all ASD participants had errors that can originate in pragmatic/discourse difficulties, seven of them had completely normal syntax in the structures we tested, and were able to produce, understand, and repeat relative clauses, Wh questions, and topicalized sentences. Only one ASD participant showed a syntactically-principled deficit similar to that of individuals with SyDLI. We conclude that not all individuals with ASD have syntactic difficulties, and that even when they fail in a syntactic task, this does not necessarily originate in a syntactic impairment. This shows that looking only at the total score in a syntactic test may be insufficient, and a fuller picture emerges once the performance on different structures and the types of erroneous responses are analyzed.

Separability of active semantic and phonological maintenance in verbal working memory

Article

Full-text available

Mar 2018
PLOS ONE

Ryoji Nishiyama

Models of verbal working memory that incorporate active memory maintenance, long-term memory networks, and attention control have been developed. Current studies suggest that semantic representations of words, evoked via long-term memory networks, are actively maintained until they are needed to fulfill a role. In other words, it is possible that some mechanism actively refreshes semantic representations of words, analogous to but independently from articulatory rehearsal which refreshes phonological representations. One valuable piece of evidence is a double dissociation, observed in a dual task paradigm in which manual tapping disrupted a semantic memory task while articulatory suppression disrupted a phonological memory task. However, in that study, the secondary tasks could have competed not only with the maintenance but also with the encoding activities. Additionally, the study items in the phonological memory tasks were words; hence, the discriminability of the memory tasks is doubtful. The present study, therefore, examined a potential double dissociation in situations where the secondary tasks could not compete with encoding, using a modified phonological memory task. Furthermore, this article discusses a potential mechanism for maintaining semantic representations.

Transfer effects on spoken sentence comprehension and functional communication after working memory training in stroke aphasia

Article

Feb 2018
J NEUROLINGUIST

Recent treatment protocols have been successful in improving working memory (WM) in individuals with aphasia. However, the evidence to date is small and the extent to which improvements in trained tasks of WM transfer to untrained memory tasks, spoken sentence comprehension, and functional communication is yet poorly understood. To address these issues, we conducted a multiple baseline study with three German-speaking individuals with chronic poststroke aphasia. Participants practised two computerised WM tasks (n-back with pictures and n-back with spoken words) four times a week for a month, targeting two WM processes: updating WM representations and resolving interference. All participants showed improvement on at least one measure of spoken sentence comprehension and everyday memory activities. Two of them showed improvement also on measures of WM and functional communication. Our results suggest that WM can be improved through computerised training in chronic aphasia and this can transfer to spoken sentence comprehension and functional communication in some individuals.

The impact of subcortical stroke-related aphasia on executive functions and working memory

Article

Full-text available

Feb 2023

Aphasia is a common post-stroke disorder characterized by impairments in speaking, listening, reading, and writing. Although cognitive impairments have been well studied in cortical aphasia, deficits associated with subcortical aphasia remain to be elucidated. The current study aimed to assess executive functions (EF) and working memory (WM) in patients with subcortical aphasia, and investigate the relationship between language abilities and cognition deficits. Participants of this research included patients with thalamus lesions (n = 9; mean age = 53.89 years) and healthy individuals (n = 9; mean age = 54.33 years). Assessment materials were the Mini-Mental State Examination (MMSE), Persian Western Aphasia Battery (P-WAB-1), digit span subtest of Adult Wechsler Test (WAIS-R), and Wisconsin Card Sorting Test (WCST). Obtained results revealed significant differences in all components of EF, as well as in WM forward and backward digit spans between patients and healthy individuals. However, investigating the relationship between MMSE and AQ scores and components of EF and WM revealed no significant difference. In conclusion, the findings of the present research indicated defects in cognitive functions, including WM and EF, in patients with subcortical stroke. Accordingly, it is crucial to provide optimal rehabilitation therapies for the improvement of language and cognitive problems upon subcortical aphasia.

Working with Global Aphasia: Theory and Practice

Book

Jan 2023

Sharon Adjei-Nicol

8 - Computational Models of Working Memory for Language

Article

Jul 2022

We start with a brief review of evidence that verbal working memory (WM) involves a limited capacity phonological loop capable of retaining verbal sequences for a few seconds in immediate serial recall, vocabulary acquisition, speech production, and language comprehension. The challenge of explaining how such a system handles information about serial order is discussed in the context of computational models of the immediate recall of unstructured sequences of words, letters, or digits, an extensively studied laboratory task for which there are many benchmark findings. Evaluating computational models against these benchmarks suggests a serial ordering mechanism in which items are simultaneously active before being selected for sequential output by a process of competitive queuing (CQ). Further evidence shows how this process may operate in the context of sequences that conform to various kinds of linguistic constraint. We conclude by suggesting that CQ is a promising theoretical mechanism for connecting and potentially unifying theories of WM and language processing more generally despite major differences in their scope and level of abstraction.

Part II - Models and Measures

Article

Jul 2022

Bringing together cutting-edge research, this Handbook is the first comprehensive text to examine the pivotal role of working memory in first and second language acquisition, processing, impairments, and training. Authored by a stellar cast of distinguished scholars from around the world, the Handbook provides authoritative insights on work from diverse, multi-disciplinary perspectives, and introduces key models of working memory in relation to language. Following an introductory chapter by working memory pioneer Alan Baddeley, the collection is organized into thematic sections that discuss working memory in relation to: Theoretical models and measures; Linguistic theories and frameworks; First language processing; Bilingual acquisition and processing; and Language disorders, interventions, and instruction. The Handbook is sure to interest and benefit researchers, clinicians, speech therapists, and advanced undergraduate and postgraduate students in linguistics, psychology, education, speech therapy, cognitive science, and neuroscience, or anyone seeking to learn more about language, cognition and the human mind.

Assessing the integrity of executive functioning in chronic aphasia

Article

Mar 2022

Background Executive functioning (EF) deficits can commonly co-occur with language impairments in aphasia. Despite recognizing the role of EF in language and aphasia treatment outcomes, the integrity of EF in aphasia remains to be comprehensively studied. Aims The present study aimed to comprehensively examine the integrity of EF skills in individuals with different types and severities of aphasia. Accordingly, we sought to compare the performances of persons with aphasia (PWA) and healthy controls on a broad range of verbal and nonverbal EF skills using an extensive battery of assessments. To fully understand the nature of deficits in the aphasia population, we aimed to evaluate EF performances both quantitatively and qualitatively in addition to examining group- and individual-level differences. Method Persons with aphasia (PWA) and age- and education-matched healthy controls (HC) completed a battery of verbal and nonverbal EF assessments. Between-group comparisons were carried out using quantitative and qualitative EF task scores. Additionally, we conducted individual-level analyses to examine performances within the aphasia group. The influence of aphasia severity and type on EF task performances were also evaluated. Results PWA differed significantly from HC on most EF measures. Individual-level analyses revealed marked variability in performances within the aphasia group indicating that most but not all PWA demonstrated EF deficits. PWA performed significantly more poorly than HC on both verbal and nonverbal measures with greater difficulty on verbal EF tasks. No consistent relationship was found between aphasia variables and EF task performances. Conclusion Our findings indicate that many PWA demonstrate domain-general EF deficits that are not necessarily related to the degree of their language impairments. The present study emphasizes the importance of evaluating EF more routinely in clinical practice to improve rehabilitation success for PWA.

Language treatment effects on communicative abilities and working memory in Korean-speaking agrammatic Broca’s aphasia caused by moyamoya disease: Phase II evidence from a case study

Article

Aug 2021

The present study reports on the language treatment outcomes from sentence- and story-level linguistic facilitation and its generalization effect on communicative abilities, working memory, and sentence processing in the case of an adult with Moyamoya Disease (MMD). After treatment,the patient’s overall performance, including the Aphasia Quotient, and sentence processing ability as measured by language testing, were improved. Furthermore, the treatment effects were generalizable to working memory abilities. Our case study conveys clinically meaningful implications since it is the first report on the effects of language treatment on linguistic and cognitive domains for an individual with MMD-induced agrammatic Broca’s aphasia

Syntactic priming reveals an explicit syntactic representation of multi-digit verbal numbers

Article

Jul 2021

When we say or understand verbal numbers, a major challenge to the cognitive system is the need to process the number's syntactic structure. Several studies showed that number syntax is handled by dedicated processes, however, it is still unclear how precisely these processes operate, whether the number's syntactic structure is represented explicitly, and if it is - what this representation looks like. Here, we used a novel experimental paradigm, syntactic priming of numbers, which can examine in detail the syntactic representation of multi-digit verbal numbers. In each trial, the participants - Arabic-Hebrew bilinguals and Hebrew monolinguals - heard a multi-digit number and responded orally with a random number. The syntactic structure of their responses was similar to that of the targets, showing that they represented the verbal number's syntax. This priming effect was genuinely syntactic, and could not be explained as lexical - repeating words from the target; as phonological - responding with words phonologically-similar to the target; or as a numerical distance effect - producing responses numerically close to the target. The syntactic priming effect was stronger for earlier words in the verbal number and weaker for later words, suggesting that the syntactic representation is capped by working-memory limits. We propose that syntactic priming could become a useful method to examine various aspects of the syntactic representation of numbers.

Sémantique lexicale et profils langagiers d'enfants avec autisme de langue hébraïque

Thesis

Sep 2019

Nufar Sukenik

A Morpho-Syntactic Study of Patients with Broca’s Aphasia: a Comparative Study of Serbian- and Greek-speaking Patients, PhD Thesis

Thesis

Full-text available

Jun 2011

Natasa Jovanov

The general goal of this dissertation is to investigate four basic effects (word order, morphological, language and task effects) on the different grammatical phenomena in two morphologically rich languages, Serbian and Greek, in order to determine the level to which the comprehension and the production is impaired in agrammatism. The data presented in the thesis is drawn from the study of five non-fluent aphasics, three native speakers of the Serbian and two native speakers of the Greek language. More specifically, in order to investigate the agrammatic comprehension of thematic roles and the patients’ ability to use morphological cues in both canonical and non-canonical word order, a sentence-picture matching test with orally presented dislocation, focus and restrictive relative constructions was used. The results of this test indicated a general above chance performance on constructions in canonical (SVO) order by both Greek- and Serbian-speaking agrammatics. Nevertheless, a better performance of the Greek aphasics on both focus and object relative constructions has also been found. Finally, theta-role reversal was statistically and significantly a more frequent error type in OVS in comparison to SVO order for both language groups. On the other hand, a prompted act-out test aimed to investigate the effect of movements on both discourse-linked and non-discourse linked wh-questions. The results of this task revealed an above chance performance on canonical wh-questions, which were much better understood than noncanonical equivalents by both language groups (similar results were found in Hickok & Avrutin, 1996; Avrutin, 2000; Salis & Edwards, 2005 by English-speaking agrammatics). The second experiment is comprised by two tests, a grammaticality judgment and a sentence repetition task, which aimed to examine whether agrammatics both comprehend and produce case markers and subject-verb agreement in both grammatical and ungrammatical sentences and whether they equally well comprehend and produce canonical (SVO) and non-canonical (VOS) word order combining syntactic cues with morphological ones. Finally, another goal of this second xiii experiment was to investigate whether there is a different performance by agrammatics on the judgment and the production task. The results of this experiment revealed a general above chance performance on the grammaticality judgment task by both language groups; patients also showed that they retain the ability to recognize S-V agreement (similar to Friedmann's study on Hebrew and Arabic, 2003 and Varlokosta’s et. al., 2006 and Nanousi’s et al., 2006 studies on Greek) and/or case marking errors. On the other hand, a deterioration of performance on the sentence repetition task has been noted; the patients confronted great difficulties especially in the repetition of ungrammatical constructions. It also must be emphasized that the patients of both language groups performed significantly better on SVO than on VOS clauses (in line with Friedman et al.’s results, 2001). These results suggest that although both Greek and Serbian are highly inflected languages, sentence comprehension and production of non-canonical word orders (OVS and VOS respectively) was relatively impaired and, in this respect, similar to the performance of aphasic patients with native languages with poor inflectional morphology (e.g. English). In addition, the better performance on some of the non-canonical structures (e.g. focus and object relatives) in the results of the Greek-speaking patients indicates that agrammatics of this language group managed to use some of the morphological cues in non-canonical word order in contrast to their Serbianspeaking counterparts.

A Longitudinal Functional Magnetic Resonance Imaging Study of Working Memory in Patients Following a Transient Ischemic Attack: A Preliminary Study

Article

Aug 2018

In this study, we used functional magnetic resonance imaging (fMRI) to investigate longitudinal changes in brain activation during a verbal working memory (VWM) task performed by patients who had experienced a transient ischemic attack (TIA). Twenty-five first-ever TIA patients without visible lesions in conventional MRI and 25 healthy volunteers were enrolled. VWM task-related fMRI was conducted 1 week and 3 months post-TIA. The brain activity evoked by the task and changes over time were assessed. We found that, compared with controls, patients exhibited an increased activation in the bilateral inferior frontal gyrus (IFG), right dorsolateral prefrontal cortex (DLPFC), insula, inferior parietal lobe (IPL), and cerebellum during the task performed 1 week post-TIA. But only the right IFG still exhibited an increased activation at 3 months post-TIA. A direct comparison of fMRI data between 1 week and 3 months post-TIA showed greater activation in the bilateral middle temporal gyrus, right DLPFC, IPL, cerebellum, and left IFG in patients at 1 week post-TIA. We conclude that brain activity patterns induced by a VWM task remain dynamic for a period of time after a TIA, despite the cessation of clinical symptoms. Normalization of the VWM activation pattern may be progressively achieved after transient episodes of ischemia in TIA patients.

Factive and counterfactive interpretation of embedded clauses in aphasia and its relationship with lexical, syntactic and general cognitive capacities

Article

Full-text available

Aug 2018
J NEUROLINGUIST

In factive clausal embedding ([He knows [that it is warm outside]]), the embedded clause is presupposed to be true. In non-factive embedding ([He thinks [that it is warm outside]]) there is no presupposition, and in counterfactive embedding ([It only seems [that it is warm outside]]) the embedded clause is presupposed to be false. These constructions have been investigated as a window into the complexity of language and thought, and there are disputes as to the relative contributions of lexical, syntactic or non-verbal resources in their interpretation. We designed a sentence-picture matching task to test comprehension of these constructions in a group of aphasic participants and in neurotypical controls. In particular, we tested the capacity to reach a factive or counterfactive interpretation. In factive interpretation trials, participants with aphasia performed nearly as well as controls, while in counterfactive interpretation trials they performed significantly worse. Accuracy in factive and counterfactive interpretation trials correlated with other syntactic and lexical measures. Only performances on counterfactive trials correlated with non-verbal reasoning measures. Exploratory regression models suggest that verbal and non-verbal scores were separate factors. Results indicate that a disruption of counterfactive interpretation in aphasia is linked to reduction of syntactic and/or conceptual-propositional capacities.

A Preliminary Study of the Reliability and Validity of the Korean Version of the QOL-DyS

Article

Apr 2016

Task-Specific Effects on Performance of Working Memory Measures and Their Relationship to Aphasia Severity in People with Aphasia

Article

Apr 2016

Adaptation in aphasia: revisiting language evidence

Article

Mar 2018

Background: Humans adapt to constantly changing internal and external conditions to meet survival needs. Persons with aphasia (PWA) are faced with changes in their physiological, cognitive, and affective state. They usually have physiological impairments in the frontal or temporal areas, which can lead to cognitive problems such as limited working memory, inefficient executive function, and lapse of attention. These problems have negative impacts on their language. Most PWA also experience long-term social anxiety, pressure, and other negative feelings caused by their illness. According to adaptation theory, symptoms such as omission and disfluency are not caused by deficits in language knowledge but by adaptive behaviours that PWA produce because of certain communicative purposes or the severity of aphasia. Aims: The purpose of this paper is to review the theories and facts concerning the adaptive language behaviours of PWA and to attempt to account for the features, motivations, and principles of their strategic, adaptive language. Main Contribution: To adapt to the heterogeneous concomitant cognitive and psychological impairment induced by aphasia, PWA must maximise their expression by efficiently exploiting their resources (i.e., performing normal communication in the most effortless way) following the principle of economy, which is a basic human cognitive principle. PWA employ several strategies to maintain crucial information and avoid effortful, less necessary language elements. They sometimes seek non-verbal strategies to compensate for what cannot be expressed. In this way, PWA are able to transmit information and simultaneously avoid embarrassment caused by erroneous language. Conclusions: This type of economic language use can be observed in phonology, morphology, syntax, and other levels of language. PWA’s adaptation should be taken into consideration when considering their language, so that it can be differentiated from language disorders caused by other cognitive impairments or competence loss. Sometimes language deficits are only symptoms of adaption rather than the result of impairments. Psychosocial interventions should be included in recovery programmes so that PWA can adapt in a more positive way and make full use of their language potential.

Verbal Short-term Memory Capacities and Executive Function in Semantic and Syntactic Interference Resolution during Sentence Comprehension: Evidence from Aphasia

Article

Mar 2018
NEUROPSYCHOLOGIA

This study examined the role of verbal short-term memory (STM) and executive function (EF) underlying semantic and syntactic interference resolution during sentence comprehension for persons with aphasia (PWA) with varying degrees of STM and EF deficits. Semantic interference was manipulated by varying the semantic plausibility of the intervening NP as subject of the verb and syntactic interference was manipulated by varying whether the NP was another subject or an object. Nine PWA were assessed on sentence reading times and on comprehension question performance. PWA showed exaggerated semantic and syntactic interference effects relative to healthy age-matched control subjects. Importantly, correlational analyses showed that while answering comprehension questions, PWA' semantic STM capacity related to their ability to resolve semantic but not syntactic interference. In contrast, PWA' EF abilities related to their ability to resolve syntactic but not semantic interference. Phonological STM deficits were not related to the ability to resolve either type of interference. The results for semantic STM are consistent with prior findings indicating a role for semantic but not phonological STM in sentence comprehension, specifically with regard to maintaining semantic information prior to integration. The results for syntactic interference are consistent with the recent findings suggesting that EF is critical for syntactic processing.

Syntactic Dependencies as Memorized Sequences in the Brain

Article

Dec 2005

Yosef Grodzinsky

The prospects of a cognitive neuroscience of syntax are considered with respect to functional neuroanatomy of two seemingly independent systems: Working Memory and syntactic representation and processing. It is proposed that these two systems are more closely related than previously supposed. In particular, it is claimed that a sentence with anaphoric dependencies involves several Working Memories, each entrusted with a different linguistic function. Components of Working Memory reside in the Left Inferior Frontal Gyrus, which is associated with Broca’s region. When lesioned, this area manifests comprehension disruptions in the ability to analyze intra-sentential dependencies, suggesting that Working Memory spans over syntactic computations. The unification of considerations regarding Working Memory with a purely syntactic approach to Broca’s regions leads to the conclusion that mechanisms that compute transformations—and no other syntactic relations—reside in this area.

On the Production of Axial Prepositions: Linking Figure and Ground in Broca's Aphasia: A Case Study | 61 On the Production of Axial Prepositions: Linking Figure and Ground in Broca's Aphasia: A Case Study

Article

Full-text available

May 2013

We report the case of a classic agrammatic speaker of Italian in repeating locative Figure/Ground relations via complex prepositions consisting of a locative axial preposition and a simple preposition in light of recent theoretical accounts of prepositions and the existing literature on prepositions in aphasia...

Verbal Working Memory Load Affects Regional Brain Activation as Measured by PET

Article

Full-text available

Jul 1997

We report an experiment that assesses the effect of variations in memory load on brain activations that mediate verbal working memory. The paradigm that forms the basis of this experiment is the "n-back" task in which subjects must decide for each letter in a series whether it matches the one presented n items back in the series. This task is of interest because it recruits processes involved in both the storage and manipulation of information in working memory. Variations in task difficulty were accomplished by varying the value of n. As n increased, subjects showed poorer behavioral performance as well as monotonically increasing magnitudes of brain activation in a large number of sites that together have been identified with verbal working-memory processes. By contrast, there was no reliable increase in activation in sites that are unrelated to working memory. These results validate the use of parametric manipulation of task variables in neuroimaging research, and they converge with the subtraction paradigm used most often in neuroimaging. In addition, the data support a model of working memory that includes both storage and executive processes that recruit a network of brain areas, all of which are involved in task performance.

Spoken Sentence Comprehension in Aphasia: Event-related Potential Evidence for a Lexical Integration Deficit

Article

Full-text available

Jan 1997
J COGNITIVE NEUROSCI

In this study the N400 component of the event-related potential was used to investigate spoken sentence understanding in Broca's and Wernicke's aphasics. The aim of the study was to determine whether spoken sentence comprehension problems in these patients might result from a deficit in the on-line integration of lexical information. Subjects listened to sentences spoken at a normal rate. In half of these sentences, the meaning of the final word of the sentence matched the semantic specifications of the preceding sentence context. In the other half of the sentences, the sentence-final word was anomalous with respect to the preceding sentence context. The N400 was measured to the sentence-final words in both conditions. The results for the aphasic patients (n = 14) were analyzed according to the severity of their comprehension deficit and compared to a group of 12 neurologically unimpaired age-matched controls, as well as a group of 6 nonaphasic patients with a lesion in the right hemisphere. The nonaphasic brain damaged patients and the aphasic patients with a light comprehension deficit (high comprehenders, n = 7) showed an N400 effect that was comparable to that of the neurologically unimpaired subjects. In the aphasic patients with a moderate to severe comprehension deficit (low comprehenders, n = 7), a reduction and delay of the N400 effect was obtained. In addition, the P300 component was measured in a classical oddball paradigm, in which subjects were asked to count infrequent low tones in a random series of high and low tones. No correlation was found between the occurrence of N400 and P300 effects, indicating that changes in the N400 results were related to the patients' language deficit. Overall, the pattern of results was compatible with the idea that aphasic patients with moderate to severe comprehension problems are impaired in the integration of lexical information into a higher order representation of the preceding sentence context.

The Time-Course of Lexical Access and the Role of Context: Converging Evidence from Normal and Aphasic Processing

Article

Full-text available

Jan 2000

The Effects of Focal Brain Damage on Sentence Processing: an examination of the neurological organization of a mental module

Article

Full-text available

Jan 1989
J COGNITIVE NEUROSCI

The effects of prior semantic context upon lexical access during sentence processing were examined for three groups of subjects; nonfluent agrammatic (Broca's) aphasic patients; fluent (Wernicke's) aphasic patients; and neurologically intact control patients. Subjects were asked to comprehend auditorily presented, structurally simple sentences containing lexical ambiguities, which were in a context strongly biased toward just one interpretation of that ambiguity. While listening to each sentence, subjects also had to perform a lexical decision task upon a visually presented letter string. For the fluent Wernicke's patients, as for the controls, lexical decisions for visual words related to each of the meanings of the ambiguity were facilitated. By contrast, agrammatic Broca's patients showed significant facilitation only for visual words related to the a priori most frequent interpretation of the ambiguity. On the basis of these data, we suggest that normal form-based word retrieval processes are crucially reliant upon the cortical tissue implicated in agrammatism, but that even the focal brain damage yielding agrammatism does not destroy the normally encapsulated form of word access. That is, we propose that in agrammatism, the modularity of word access during sentence comprehension is rendered less efficient but not lost. Additionally, we consider a number of broader issues involved in the use of pathological material to infer characteristics of the neurological organization of cognitive architecture.

Processing resource capacity and the comprehension of garden path sentences

Article

Full-text available

May 1996

Three experiments explored the relationship between verbal working memory capacity and the comprehension of garden path sentences. In Experiment 1, subjects with high, medium, and low working memory spans made acceptability judgments about garden path and control sentences under whole sentence and rapid serial visual presentation (RSVP) conditions. There were no significant differences between subjects with different working memory spans in the comprehension of garden path sentences in either condition. In Experiments 2A and 2B, subjects with high and low working memory spans were tested on the same materials at three RSVP rates. There were no significant differences between subjects with different working memory spans in the magnitude of the effect of garden path sentences at any presentation rate. The results suggest that working memory capacity, as measured by the Daneman and Carpenter (1980) reading span task, is not a major determinant of individual differences in the processing of garden path sentences.

Verbal Working Memory and Sentence Comprehension

Article

Full-text available

Mar 1999

This target article discusses the verbal working memory system used in sentence comprehension. We review the idea of working memory as a short duration system in which small amounts of information are simultaneously stored and manipulated in the service of a task and that syntactic processing in sentence comprehension requires such a storage and computational system. We inquire whether the working memory system used in syntactic processing is the same as that used in verbally mediated tasks involving conscious, controlled processing. Various forms of evidence are considered: the relationship between individual differences in working memory and individual differences in the efficiency of syntactic processing; the effect of concurrent verbal memory load on syntactic processing; and syntactic processing in patients with poor short term memory, poor working memory, or aphasia. The experimental results suggest that the verbal working memory system specialized for assigning the syntactic structure of a sentence and for using that structure in determining sentence meaning is distinct from the working memory system that underlies the use of sentence meaning to accomplish further functions. We present a theory of the components of the verbal working memory system and suggestions as to its neural basis.

Working memory constraints on the processing of syntactic ambiguity

Article

Full-text available

Jan 1992

We propose a model that explains how the working-memory capacity of a comprehender can constrain syntactic parsing and thereby affect the processing of syntactic ambiguities. The model's predictions are examined in four experiments that measure the reading times for two constructions that contain a temporary syntactic ambiguity. An example of the syntactic ambiguity is The soldiers warned about the dangers . . . ; the verb warned may either be the main verb, in which case soldiers is the agent; or the verb warned may introduce a relative clause, in which case soldiers is the patient of warned rather than the agent, as in The soldiers warned about the dangers conducted the midnight raid. The model proposes that both alternative interpretations of warned are initially activated. However, the duration for which both interpretations are maintained depends, in part, on the reader's working-memory capacity, which can be assessed by the Reading Span task (Daneman & Carpenter, 1980). The word-by-word reading times indicate that all subjects do additional processing after encountering an ambiguity, suggesting that they generate both representations. Furthermore, readers with larger working-memory capacities maintain both representations for some period of time (several words), whereas readers with smaller working-memory capacities revert to maintaining only the more likely representation.

Agrammatic Comprehension of relative clauses

Article

Full-text available

Nov 1989

Yosef Grodzinsky

Four hypotheses that attempt to account for the comprehension deficit in agrammatism are put to an empirical test. The interest in them is in that they all view the deficit as highly selective. The first, proposed by D. Caplan and C. Futter (1986, Brain and Language, 27, 117-134), argues that agrammatic patients cannot carry out normal syntactic analysis beyond the category label of each incoming lexical item and are reduced to the use of a cognitive strategy that commends assignment of thematic roles to noun phrases merely by their linear position in the string. A second, less radical hypothesis (Y. Grodzinsky, 1986a, Brain and Language, 27, 135-159), accounts for the deficit differently, by deleting a particular kind of syntactic object (trace) from the otherwise normal representation, and augmenting the resulting, underspecified representation by a strategy, whose use is quite restricted. A third account that is tested contends that agrammatic aphasics fail to comprehend perceptually complex constructions, where the metric for complexity is determined by results obtained from comprehension tests of normal listeners. The fourth account (M. F. Schwartz, M. C. Linebarger, E. M. Saffran, and D. S. Pate, 1987, Language and Cognitive Processes, 2, 85-113) argues that the thematic transparency of a construction (whether or not thematic roles are assigned directly to positions) is the best predictor of the manner by which agrammatics can handle it. An empirical test is thus constructed, both to extend the evidential basis concerning the comprehension skills of these patients and to distinguish between the accounts. Four types of relative clauses are presented to the patients, where embedding type (center vs. right) is one variable, and location of gap (subject vs. object position) is the other. The patients are tested in a sentence-picture matching paradigm. The finding, that is rather robust, is that gap location is the best predictor of agrammatic performance: the patients perform well above chance on both types of subject gap relatives, and at chance levels on object gaps. It is then shown that the Trace-Deletion Hypothesis (Grodzinsky, 1986a) is the only one among the accounts considered that is compatible with these data.

The role of structure in coreference during sentence comprehension

Article

Full-text available

Feb 1989

This paper examines the role of syntactic constraints on the reactivation and assignment of antecedents to explicit and implicit anaphoric elements during sentence comprehension. Evidence from on-line studies examining the time course of coreference processing supports the view that reactivation of potential antecedents is restricted by grammatical constraints when they are available. When structural information cannot serve to constrain antecedent selection, then pragmatic information may play a role, but only at a later point in processing.

The Uses of Short-Term Memory: A Case

Article

Full-text available

Dec 1986

It has been widely claimed that the systems employed in tasks of immediate memory have a function in the comprehension of speech; these systems, it has been proposed, are used to hold a representation of the speech until a syntactic analysis and interpretation have been completed. Such a holding function is meant to be especially important where the sentences heard are long or complex. It has thus been predicted that subjects with impaired short-term memory performance would show deficits in comprehension of such materials. In this study, one subject with impaired phonological processing and a severely reduced digit span was tested on a range of tasks requiring the syntactic analysis, memory and comprehension of long and complex material. She was found to be unimpaired on syntactic analysis and comprehension, but not on sentence repetition. The implications for models of short-term memory are discussed.

Coreference Processing and Levels of Analysis in Object-Relative Constructions; Demonstration of Antecedent Reactivation with the Cross-Modal Priming Paradigm

Article

Full-text available

Feb 1996

This paper is concerned with two related issues in sentence processing--one methodological and one theoretical. Methodologically, it provides an unconfounded test of the ability of the cross-modal lexical priming task, when used appropriately, to provide detailed evidence about the time-course of antecedent reactivation during sentence processing. Theoretically, it provides a study of the nature of the representation that is examined when a reference-seeking element is linked to its antecedent during the processing of object-relative clause constructions. In these studies, subjects heard sentences which contained a lexical ambiguity placed in a strong biasing context. In one study this ambiguous word was the "moved" or "fronted" object of the verb in an object-relative construction. A cross-modal lexical priming (CMLP) naming task was used to determine whether one or more of the meanings of the ambiguity are activated at three temporally distinct points during the sentence: (1) immediately after the lexical ambiguity (Study 1); (2) a later point that was 700 milliseconds before the offset of the main verb (Study 2); (3) immediately after this main verb (at the gap in this filler-gap construction) (Study 2). The probes in the CMLP task were controlled for potential confounds. The results demonstrate the following: At Test Point 1, all meanings of the ambiguity were activated; at Test Point 2, neither meaning of the ambiguity was (still) activated; at Test Point 3, only a single (context-relevant) meaning of the ambiguity was reactivated. It is concluded that an underlying (deep; non-surface-level) memorial representation of the sentence is examined during the process of linking an antecedent to a structural position requiring a referent, and that the CMLP task provides an unbiased measure of this reactivation. Further, it is concluded that this effect cannot be accounted for under a "compound cue" (Ratcliff & McKoon, 1994) explanation.

Short-term memory and language comprehension: a critical review of the neuropsychological literature

Chapter

Jul 1990

This work summarizes the empirical and theoretical work on impairments of short-term memory (often caused by damage in the left cerebral hemisphere) and contains chapters from virtually every scientist in Europe and North America working on the problem. The chapters present evidence from both normal and brain-damaged patients. Two neuropsychological issues are discussed in detail: first, the specific patterns of immediate memory impairment resulting from brain damage with reference to both multistore and the interactive-activation theoretical frameworks. Also considered is the relation between verbal STM and sentence comprehension disorders in patients with a defective immediate auditory memory: an area of major controversy in more recent years.

Syntactic Dependencies as Memorized Sequences in the Brain

Article

Dec 2005

Yosef Grodzinsky

Activation of prefrontal cortex in a non-spatial working memory task with fMRI

Article

Jan 1994

Journal of Verbal Learning and Verbal Behavior

Article

Jan 1979

D. Swinney

Short-term retention of sentences without "short-term memory"

Article

Jul 1990

Encoding and storage in working memory during sentence comprehension

Chapter

Jan 2002

In this article we will discuss evidence from a number of recent neuroimaging experiments. These experiments suggest that three areas play a role in sentence comprehension: the left inferior frontal gyrus (LIFG), the left posterior superior temporal gyrus (STG), and the anterior temporal lobe (ATL). The left posterior STG appears to be important for sentential processing, since activation in this area increases as a function of the structural complexity of the sentences which must be comprehended. The LIFG, on the other hand, is activated by storage of lexical information as well as by sentential complexity. It is possible to explain a range of experimental results by hypothesizing that this area is responsible for storage of both lexical and phrasal information during comprehension. The ATL does not respond to structural complexity during sentence comprehension, but it is consistently more activated during comprehension of sentences than of word lists. On the basis of evidence which shows that the ATL is important for encoding in short-term verbal memory tasks, we suggest that it is responsible for encoding of information about words for use later in comprehension.

Verbal Working Memory and Its Connections to Language Processing

Chapter

Dec 2000

The working memory (WM) is the cognitive mechanism that allows one to keep a limited amount of information active. It is not the case that there is a single general-purpose working memory; rather, research indicates that there are different kinds of working memories for different kinds of information. The neuroimaging experiments support the claim that verbal WM consists of a rehearsal process and a storage process. These studies further indicate that the rehearsal process is implemented by neural mechanisms involved in speech. When the image acquired during the control task is subtracted from that acquired during the memory task, there are several sites of activation, mostly in the left hemisphere. Thus verbal working memory clearly depends on language, or at least the phonological component of language. The studies of neurological patients who have defects in short-term storage suggest that verbal WM is sometimes used as backup, particularly when the syntactic or semantic complexity of the sentence outstrips the capacity of normal processing mechanisms. But the patient findings on this point are quite variable.

Working Memory and Inference Revision in BrainDamaged and Normally Aging Adults

Article

Aug 1994

This study examined the association between estimated working memory (WM) capacity and comprehension of passages that required revision of an initial interpretation. Predictions stemmed from the recently elaborated theory of capacity-constrained comprehension (Just & Carpenter, 1992, Psychological Review, 99, 122–149), which includes as a major feature the principle that WM influences comprehension only as processing demands approach or exceed the limits of capacity. As anticipated from task analysis, correlations between unilaterally brain-damaged patients' estimated WM capacity and discourse comprehension performance were minimal for nondemanding measures, and increased in magnitude with task processing requirements. Most notably, a meaningful correlation (/r/ greater than .50) emerged only for the task judged to involve the most demanding comprehension processes, for adults with right hemisphere brain damage. No meaningful associations between estimated WM capacity and task performance were observed for normally aging subjects, who were not expected to have difficulty with any of our comprehension measures. The nature of WM deficits in brain-damaged adults (total capacity, vs. resource allocation, vs. slow or otherwise faulty component processing operations) is considered, and some existing work is interpreted from a cognitive resource perspective. Theoretical implications and clinical applicability of the working memory/resource framework are also discussed.

Re-examining Evidence for Separate Sentence Processing Resources

Article

Waters et al. (1987) Re-examined Goal. Re-examining the evidence for separate working memory systems from a whole-sentence anomaly-judgment experiment reported in Waters, Caplan, & Hildebrandt (1987). Manipulations. Propositions: 1 proposition sentences (1P) vs. 2 proposition sentences (2P) Relative Clause: Subject-relative (SR) vs. object-relative (OR) clauses Memory load: No load vs. load (counting from 1 to 6 out loud) Example Sentences. 1PSR: It was the gangsters that broke into the warehouse. 1POR: It was the broken clock that the jeweller adjusted. 2PSR: The man hit the landlord that requested the money. 2POR: The meat that the butcher cut delighted the customer. The Separate Resource Hypothesis. Waters et al. (1987) argue for separate resources because: a) syntactic and propositional effects did not interact, and b) propositional, but not syntactic complexity, interacted with articulatory suppression (cf. Baddeley, 1986). A Possible Confound. Some of Waters et al.'s (1987) 2P, but none of their 1P sentences contained center-embedded clauses. Thus, the propositional effect may have been syntactic rather than semantic. Experiment 1: A Replication without Center-Embedded Clauses Method Subjects. Thirty-six undergraduate students served as paid subjects (native speakers of Dutch with normal vision). Materials. Het waren de duivels die de schepper vervloekten.

Language Processing and Working Memory: Neuropsychological Evidence for Separate Phonological and Semantic Capacities

Article

Feb 1994

The short-term memory and sentence-processing abilities of two brain-damaged patients were investigated. Although both patients showed similar reductions in span, one patient showed worse retention on span tasks for semantic than phonological information, whereas the other patient showed the reverse. Their performance on the sentence-processing tasks was consistent with these contrasting short-term memory deficits. On sentence repetition, the patient with the phonological retention deficit was more impaired than the patient with the semantic retention deficit, whereas on sentence comprehension, the patient with the semantic retention deficit was more impaired. The results imply that the memory processes involved in span overlap with those involved in sentence processing. Furthermore, the dissociations in the patients′ performance imply that there are separate capacities for phonological and semantic retention. Thus, the results support a multiple-capacity rather than a single-capacity view of working memory.

The Western Aphasia Battery

Article

Jan 1982

Andrew Kertesz

Dissociation of Storage and Rehearsal in Verbal Working Memory: Evidence From Positron Emission Tomography

Article

Jan 1996

Current cognitive models of verbal working memory include two components a phonological store and a rehearsal mechanism that refreshes the contents of this store We present research using positron emission tomography (PET) to provide further evidence for this functional division In Experiment 1, subjects performed a variant of Sternberg's (1966) item recognition task Experiment 2 used a continuous memory task with control conditions designed to separate the brain regions underlying storage and rehearsal The results show that independent brain regions mediate storage and rehearsal In Experiment 3, a dual-task procedure supported the assumption that these memory tasks elicited a rehearsal strategy

On the Structure of Verbal Short-term Memory and its Functional Role in Sentence Comprehension: Evidence from Neuropsychology

Article

Mar 1991

We present a case of a patient with a disorder of short-term memory. BO has a reduced span (2 to 3 items), no recency effect in free recall, and rapid forgetting in Brown-Peterson tasks, establishing her as a patient with impaired short-term verbal memory functions. She shows no effect of either phonological similarity or word length in recall of auditory or written word lists, but some recency effect under recall-from-end conditions and better performance on Brown-Peterson tasks in an unfilled than in a filled condition. This pattern of performance is interpreted as being consistent with a primary disturbance of the articulatory rehearsal processes of S.T.M. and possibly some impairment of the phonological store (using Baddeley's 1986 terminology). Her aphasic disturbance—apraxia of speech—is also consistent with a disturbance of articulatory rehearsal. BO shows a retained ability to extract phonology from print, including an ability to apply sublexical grapheme-phoneme correspondences, thus indicating that the rehearsal and transcoding functions associated with articulatory mechanisms are dissociable. Her improved performance on unfilled delays in Brown-Peterson testing, as well as her overt attempts to rehearse in this condition, also establishes a dissociation between rehearsal in span and in delayed recall tasks. BO shows excellent comprehension of a wide variety of syntactic structures with auditory, written, and speeded written presentations, indicating that articulatory rehearsal is not needed for the assignment of syntactic structure and its utilisation to establish aspects of prepositional semantics (thematic roles and co-indexation of noun phrases). BO makes errors referable to the maintenance of particular items in propositional memory systems, consistent with the view that the role of articulatory rehearsal mechanisms in sentence comprehension involves maintenance of items in an interpreted (semantic) structure.

Phonological short-term store, phonological processing and sentence comprehension: A neuropsychological case study

Article

May 1984

Phonological processing and speech comprehension were investigated in a patient with left hemisphere damage and a grossly reduced auditory verbal span, attributed to a selective impairment of a phonological short-term store (Vallar & Baddeley, in press). Her phonological processing perfomance was well within the normal range as measured by phonological discrimination, the assignment of stress to words, and rhyme judgement. Comprehension of individual words and of short sentences was unaffected. However, the patient's comprehension of long sentences was defective, whether presented visually or auditorily, when preservation of the specific wording was essential for understanding. These results suggest a dissociation between the processes that perform phonological analysis of verbal information and a phonological short-term store, the latter being selectively impaired in the present case. The pattern of deficit observed in this case suggests that such a system may be useful for comprehending sentences, whenever the verbatim content has to be retained in order to extract meaning

Theoretical perspectives on language deficits

Article

Jan 1990

Yosef Grodzinsky

Grammatical transformations activate the language regions — An FMRI study

Article

Jun 2001

1988: From Neuropsychology to Mental Structure

Article

Sep 1991
BEHAV BRAIN SCI

Tim Shallice

Neuropsychological results are increasingly cited in cognitive theories although their methodology has been severely criticised. The book argues for an eclectic approach but particularly stresses the use of single-case studies. A range of potential artifacts exists when inferences are made from such studies to the organisation of normal function – for example, resource differences among tasks, premorbid individual differences, and reorganisation of function. The use of “strong” and “classical” dissociations minimises potential artifacts. The theoretical convergence between findings from fields where cognitive neuropsychology is well developed and those from the normal literature strongly suggests that the potential artifacts are not critical. The fields examined in detail in this respect are short-term memory, reading, writing, the organisation of input and output speech systems, and visual perception. Functional dissociation data suggest that not only are input systems organised modularly, but so are central systems. This conclusion is supported by findings on impairment of knowledge, visual attention, supervisory functions, memory, and consciousness.

Neuropsychological Impairments of Short-Term Memory

Article

Jan 1995

Individual Differences and Probabilistic Constraints in Syntactic Ambiguity Resolution

Article

Aug 1995

Two experiments investigated the role of individual differences in reading span in the comprehension of ambiguous sentences that were resolved with a syntactically simple interpretation. Previous research showed that high but not low reading span subjects had longer reading times for such sentences compared to unambiguous controls, a result that had been attributed to high span subjects maintaining more alternative interpretations of the ambiguity than did low span subjects (MacDonald, Just, & Carpenter, 1992). Experiment 1 replicated this reading time pattern but also showed that the individual differences were attributable to differential sensitivity to probabilistic constraints in the stimuli, in that only high span subjects were sensitive to the relative plausibility of alternative interpretations of the ambiguity. Experiment 2 demonstrated that the source of these differences was in the ability to use plausibility constraints during comprehension, not in constraint knowledge across the two groups. The implications of these results for studies of individual differences and for theories of syntactic ambiguity resolution are discussed.

Language and the Brain: Representation and Processing (review)

Article

Dec 2001
LANGUAGE

Celso Vieira Novaes

Syntactic transparency and sentence interpretation in aphasia

Article

Apr 1987

A semantic anomaly judgement test was used to test the hypothesis that sentence comprehension errors by agrammatic aphasics arise as a consequence of faulty mapping from syntactic functions to thematic roles. In one condition, anomalies arose out of a thematic role reversal which was carried by the syntactic structure (e.g., # The worm swallowed the bird). Mis-mapping in these cases would have the effect of altering plausibility and hence resulting in erroneous judgments. In a second condition, mismapping was of no consequence (e.g., # The cat divorced the milk). Effects of sentence length (“Padding”) and of the transparency with which thematic roles are syntactically encoded (“Moved-arguments”) were examined across both types of anomaly. Overall, the performance pattern of agrammatics reveals considerable sensitivity to syntactic structure per se. Their difficulty seems to lie in the utilization of syntactic information for the assignment of thematic roles, particularly where the syntactic relationship between the verb and its noun arguments is not transparently evident in surface structure.

A Capacity Approach to Syntactic Comprehension Disorders: Making Normal Adults Perform like Aphasic Patients

Article

Dec 1994
COGN NEUROPSYCHOL

This paper presents a theory of syntactic comprehension disorders in aphasic patients. In line with some recent proposals, the current theory assumes that aphasic patients still possess the structural (syntactic) and procedural knowledge necessary to perform syntactic analysis. This paper, however, postulates that patients' comprehension deficits originate, at least in part, from reductions in working memory capacity for language. Based on a recently developed theory of capacity constraints in normal language comprehension (Just&Carpenter, 1992), the theory explains how reductions in working memory capacity can lead to the pattern of comprehension breakdown in aphasics, which can be characterised as a conjoint function of the patient's severity level and the structural complexity of the sentence. As supporting evidence for the theory, we report two “simulation” experiments in which we increased the computational demands on normal adults of varying working memory capacities and thereby induced in them the interaction of “severity” by complexity usually observed among aphasic patients.

Memory Limitations and Structural Forgetting: The Perception of Complex Ungrammatical Sentences as Grammatical

Article

Jun 1999

Results from an English acceptability-rating experiment are presented which demonstrate that people nd doubly nested relative clause structures just as acceptable when only two verb phrases are included instead of the grammatically required three. Furthermore, the experiment shows that such sentences are acceptable only when the intermediate verb phrase is omitted. A number of specic accounts of forgetting are considered. Two early proposed theories of this effect, the disappearing syntactic nodes hypothesis (Frazier, 1985) and the least recent nodes hypothesis (Gibson, 1991), are not consistent with the experimental results. The results, together with other acceptability patterns, suggest that the representations that are retained (and subsequently forgotten) in processing sentences consist of the lexical word-strings processed thus far. Three possible accounts of the results are considered: (1) the high memory cost pruning hypothesis within the framework of Gibson (1998); (2) a recency/primacy account; and (3) a connectionist account (Christiansen & Chater, in press).

Activation of prefrontal cortex in a nonspatial workingmemory task with functional MRI

Article

Jan 1994
HUM BRAIN MAPP

Functional magnetic resonance imaging (fMRI) was used to examine the pattern of activity of the prefrontal cortex during performance of subjects in a nonspatial working memory task. Subjects observed sequences of letters and responded whenever a letter repeated with exactly one nonidentical letter intervening. In a comparison task, subjects monitored similar sequences of letters for any occurrence of a single, prespecified target letter. Functional scanning was performed using a newly developed spiral scan image acquisition technique that provides high-resolution, multislice scanning at approximately five times the rate usually possible on conventional equipment (an average of one image per second). Using these methods, activation of the middle and inferior frontal gyri was reliably observed within individual subjects during performance of the working memory task relative to the comparison task. Effect sizes (2–4%) closely approximated those that have been observed within primary sensory and motor cortices using similar fMRI techniques. Furthermore, activation increased and decreased with a time course that was highly consistent with the task manipulations. These findings corroborate the results of positron emission tomography studies, which suggest that the prefrontal cortex is engaged by tasks that rely on working memory. Furthermore, they demonstrate the applicability of newly developed fMRI techniques using conventional scanners to study the associative cortex in individual subjects. © 1994 Wiley-Liss, Inc.

Accessing lexical ambiguities during sentence comprehension: Effects of frequency of meaning and contextual bias

Article

May 1981

Two hypotheses concerning the nature of lexical access, the exhaustive access and the terminating ordered search hypotheses, were examined in two separate studies using a crossmodal lexical priming task. In this task, subjects listened to sentences that were biased toward either the primary interpretation (a meaning occurring 75% or more of the time) or a secondary interpretation (a meaning occurring less than 25% of the time) of a lexical ambiguity that occurred in each sentence. Simultaneously, subjects made lexical decisions about visually presented words. Decisions to words related to both the primary and secondary meanings of the ambiguity were facilitated when presented immediately following occurrence of the ambiguity in the sentence. This effect held under each of the two biasing context conditions. However, when they were presented 1.5 sec following occurrence of the ambiguity, only visual words related to the contextually relevant meaning of the ambiguity were facilitated. These results support the exhaustive access hypothesis. It is argued that lexical access is an autonomous subsystem of the sentence comprehension routine in which all meanings of a word are momentarily accessed, regardless of the factors of contextual bias or bias associated with frequency of use.

Individual differences in syntactic processing: The role of working memory

Article

Oct 1991

The results of two experiments indicate that individual differences in syntactic processing are governed in part by the amount of working memory capacity available for language comprehension processes. Reading the verbs of an object relative sentence, such as The reporter that the senator attacked admitted the error, takes more time for readers with less working memory capacity for language, and their resulting comprehension is less accurate. Experiment 1 investigated the effects of a concurrent working memory load and found that with no load or a small memory load many Low Span readers comprehended object relative sentences very poorly although their reading times in the critical area of these sentences were greater than those of High Span subjects. Experiment 2 replicated the reading time effects of Experiment 1 for object relative sentences and showed that pragmatic information improved the comprehension of the lower capacity readers, although their use of this information was limited to the clause in which it was presented.

The consequences of reduced memory span for the comprehension of semantic versus syntactic information

Article

Feb 1990

Aphasic patients with restricted memory spans were assessed on their comprehension of syntactically simple sentences varying in numbers of content words and on their comprehension of sentences matched in content words but varying in syntactic complexity. Three different presentation modes were used: unlimited visual presentation, limited visual presentation, and auditory presentation. The difference between performance in the unlimited and limited modes was used as a measure of the extent to which memory decrements caused comprehension failure. These difference scores were related to memory span in order to assess whether the memory involved in sentence processing overlaps that assessed by a memory span task. For the sentences varying in number of content words, performance was worse for the limited presentation modes than the unlimited mode, and the difference between unlimited and limited presentation modes was highly related to memory span. For the sentences varying in syntactic complexity, there was no clear reduction in performance for limited presentation modes, and the difference scores did not relate to memory span. The results support the view that the processing of sentences with many content words draws on the short-term memory capacity assessed by memory span, while the processing of syntactic complexity does not.

Lexical Access During Sentence Comprehension: (Re)Consideration of Context Effects

Article

Dec 1979

David A. Swinney

The effects of prior semantic context upon lexical access during sentence comprehension were examined in two experiments. In both studies, subjects comprehended auditorily presented sentences containing lexical ambiguities and simultaneously performed a lexical decision task upon visually presented letter strings. Lexical decisions for visual words related to each of the meanings of the ambiguity were facilitated when these words were presented simultaneous with the end of the ambiguity (Experiment 1). This effect held even when a strong biasing context was present. When presented four syllables following the ambiguity, only lexical decisions for visual words related to the contextually appropriate meaning of the ambiguity were facilitated (Experiment 2). Arguments are made for autonomy of the lexical access process of a model of semantic context effects is offered.

Individual differences in working memory and reading

Article

Aug 1980

Individual differences in reading comprehension may reflect differences in working memory capacity, specifically in the trade-off between its processing and storage functions. A poor reader's processes may be inefficient, so that they lessen the amount of additional information that can be maintained in working memory. A test with heavy processing and storage demands was devised to measure this trade-off. Subjects read aloud a series of sentences and then recalled the final word of each sentence. The reading span, the number of final words recalled, varied from two to five for 20 college students. This span correlated with three reading comprehension measures, including verbal SAT and tests involving fact retrieval and pronominal reference. Similar correlations were obtained with a listening span task, showing that the correlation is not specific to reading. These results were contrasted with traditional digit span and word span measures which do not correlate with comprehension.

Dissociation of algorithmic and heuristic processes in language comprehension: Evidence from aphasia* 1

Article

Nov 1976

Three groups of aphasic patients, Broca's, Conduction, and Wernicke's, and a nonaphasic patients control group were tested for comprehension of object-relative center-embedded sentences. The sentences were of three types: sentences in which semantic constraints between words allowed the subjects to assign a correct semantic reading of the sentence without decoding the syntax, sentences in which semantic constraints were relaxed and for which a correct reading was only possible with knowledge of syntactic relationships among words, and sentences which described highly improbable events. The subjects' task was to choose which of two pictures captured the meaning expressed in the sentence. Broca's and Conduction aphasics performed near perfectly on sentences where they could use semantic information. Their performance dropped to chance when they had to use syntactic information. These results support a neuropsychological dissociation of heuristic and algorithmic processes based primarily, though not exclusively, on semantic and syntactic information, respectively.

Immediate memory for word lists and sentences in a patient with deficient auditory short-term memory

Article

Nov 1975

This study of a patient with a mild conduction aphasia again traces impaired repetition to faulty auditory short-term memory. In serial recall, for example, the normal recency effect was absent with auditory but not visual lists. The patient's behavior in immediate memory tasks was in some ways more characteristic of delayed recall, suggesting that an intact long-term memory was responsible for the residual short-term performance. The patient also showed a remarkable ability to paraphrase sentences he could not repeat verbatim, a result which has implications for the role of auditory memory in language comprehension.

Contribution of articulatory rehearsal to short-term memory: Evidence from a case of selective disruption

Article

Dec 1992

We describe a brain-damaged patient with disturbed articulatory rehearsal in whom all predictions derived from a working memory model were fulfilled. The patient showed a reduced verbal span, no word-length effect on immediate recall in both the visual or the auditory modalities, no phonological similarity effect in the visual modality, and no effect of articulatory suppression. A slowed overt articulation rate provided independent evidence for disrupted articulatory rehearsal. The other components of working memory, the visuospatial scratch-pad, phonological storage system, and central executive, were functional. The selectivity of the deficit can be taken as evidence for the specific role of articulatory rehearsal in working memory.

A Capacity Theory of Comprehension: Individual Differences in Working Memory

Article

Feb 1992

A theory of the way working memory capacity constrains comprehension is proposed. The theory proposes that both processing and storage are mediated by activation and that the total amount of activation available in working memory varies among individuals. Individual differences in working memory capacity for language can account for qualitative and quantitative differences among college-age adults in several aspects of language comprehension. One aspect is syntactic modularity: The larger capacity of some individuals permits interaction among syntactic and pragmatic information, so that their syntactic processes are not informationally encapsulated. Another aspect is syntactic ambiguity: The larger capacity of some individuals permits them to maintain multiple interpretations. The theory is instantiated as a production system model in which the amount of activation available to the model affects how it adapts to the transient computational and storage demands that occur in comprehension.

On deriving the properties of agrammatic comprehension

Article

Feb 1991

Several recent studies characterize agrammatic comprehension as a computational rather than a conceptual deficit. A restriction in the computational capacity of the processor may affect sentence comprehension performance unevenly due to the varying demands imposed by different sentence structures and different tasks. It is argued that structures involving longer inferential chains suffer greater degradation than structures involving shorter inferential chains. Many of the observed properties of agrammatic comprehension may be seen to follow from this principle alone.

The allocation of memory resources during sentence comprehension: Evidence from the elderly

Article

Jun 1995

Two experiments were carried out to examine the ability of elderly subjects to establish syntactically governed dependency relations during the course of sentence comprehension. The findings reveal the manner in which memory constraints operate during syntactic processing.

Working memory and inference revision in Brain-Damaged and normally aging adults

Article

Aug 1994
J Speech Hear Res

This study examined the association between estimated working memory (WM) capacity and comprehension of passages that required revision of an initial interpretation. Predictions stemmed from the recently elaborated theory of capacity-constrained comprehension (Just & Carpenter, 1992, Psychological Review, 99, 122-149), which includes as a major feature the principle that WM influences comprehension only as processing demands approach or exceed the limits of capacity. As anticipated from task analysis, correlations between unilaterally brain-damaged patients' estimated WM capacity and discourse comprehension performance were minimal for nondemanding measures, and increased in magnitude with task processing requirements. Most notably, a meaningful correlation (/r/ greater than .50) emerged only for the task judged to involve the most demanding comprehension processes, for adults with right hemisphere brain damage. No meaningful associations between estimated WM capacity and task performance were observed for normally aging subjects, who were not expected to have difficulty with any of our comprehension measures. The nature of WM deficits in brain-damaged adults (total capacity, vs. resource allocation, vs. slow or otherwise faulty component processing operations) is considered, and some existing work is interpreted from a cognitive resource perspective. Theoretical implications and clinical applicability of the working memory/resource framework are also discussed.

Spontaneous Recovery of Impaired Memory Span: Does Comprehension Recover?

Article

Apr 1993
CORTEX

We have previously described a patient, T.B., who had a memory span of two digits and a sentence span of three words. He showed no evidence of effects of either phonological similarity or word length on span and his deficit was interpreted as reflecting the impaired functioning of the phonological loop component of working memory. Analysis of his language comprehension indicated normal processing of short sentences, together with a marked deficit in understanding long sentences, whether these were presented visually or auditorily (Baddeley and Wilson, 1988). When re-tested after several years, T.B.'s memory span had increased to nine digits, and showed clear effects of phonological similarity and word length. His performance on a series of language comprehension tests indicated a complete recovery, although he continued to show impairment on two tests of phonological awareness. These results are consistent with the proposed link between phonological working memory and language comprehension. In addition, they indicate a dissociation between short-term phonological memory and phonological awareness.

Judgments of Semantic Anomaly in Agrammatic Patients: Argument Movement, Syntactic Complexity, and the Use of Heuristics

Article

Aug 1996

Two studies on the judgment of semantic anomaly of sentences in agrammatic aphasia are reported. The primary question was whether performance on this task would be negatively affected by sentence complexity. In a first experiment, we repeated part of the study by Schwartz, Linebarger, Saffran, and Pate (Language and Cognitive Processing, 2, 85-113, 1987). With a group of 15 Dutch-speaking agrammatics, we obtained a small but significant negative effect of "lexical padding": sentences like "#the puppy ran around excitedly and accidently dropped the little boy onto the wet grass which upset Louise" elicited more errors than their simple counterparts, "#the puppy dropped the little boy." In our second study, we looked at (a) the effect of sentence embedding (e.g., "the doctor, who was tired of climbing a staircase, examined the patient") and (b) the effect of incorporating a "distractor agent" in the sentences, that is, an NP that could serve as a possible agent of the critical action (e.g., "the doctor, who had talked to the nurse, examined the patient"). In addition we employed sentences with moved arguments (e.g., "it was the patient who the doctor examined"). There were two major conclusions. First, syntactic complexity has a strong negative effect on anomaly judgments. Second, patient use a linear-order strategy to deal with the task. Results are discussed in terms of a range of recent approaches to agrammatic comprehension, not only representational hypotheses, based upon linguistic theory, but also processing accounts.

A Parametric Study of Prefrontal Cortex Involvement in Human Working Memory

Article

Feb 1997

Although recent neuroimaging studies suggest that prefrontal cortex (PFC) is involved in working memory (WM), the relationship between PFC activity and memory load has not yet been well-described in humans. Here we use functional magnetic resonance imaging (fMRI) to probe PFC activity during a sequential letter task in which memory load was varied in an incremental fashion. In all nine subjects studied, dorsolateral and left inferior regions of PFC were identified that exhibited a linear relationship between activity and WM load. Furthermore, these same regions were independently identified through direct correlations of the fMRI signal with a behavioral measure that indexes WM function during task performance. A second experiment, using whole-brain imaging techniques, both replicated these findings and identified additional brain regions showing a linear relationship with load, suggesting a distributed circuit that participates with PFC in subserving WM. Taken together, these results provide a "dose-response curve" describing the involvement of both PFC and related brain regions in WM function, and highlight the benefits of using graded, parametric designs in neuroimaging research.

Sentence comprehension and working memory limitation in aphasia: A dissociation between semantic-syntactic and phonological reactivation

Abstract

No full-text available

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