No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Impaired language production in asymptomatic carotid stenosis
Abstract
This article aims to investigate the possible impact of carotid stenosis, i.e., the atherosclerotic narrowing of the inner surface of the carotid artery, on language performance. The majority of patients with carotid stenosis are considered asymptomatic, as they have not experienced retinal or focal cerebral dysfunction. Here we challenge the traditional assumption that such patients are asymptomatic with regard to neurocognitive functions by demonstrating that chronic cerebral hypoperfusion may have a significant impact on language performance. Twenty-four patients with 50–99% asymptomatic carotid stenosis and 24 healthy controls participated in this study. Language performance was tested with an elicited production task, in which participants had to produce regularly and irregularly inflected Hungarian noun forms. The dependent variable was the amount of errors. Compared to healthy controls, patients with carotid artery stenosis demonstrated lower overall performance on the language production task. Additionally, patients with bilateral stenosis produced more errors than patients with unilateral stenosis. Importantly, patients with the lowest degree (i.e., 50%) of carotid artery narrowing already exhibited considerable language impairment. These results support the accumulating evidence that hypoperfusion secondary to carotid stenosis may be functionally relevant despite the so called ‘asymptomatic’ status of the patients. These findings also highlight the need for including neurocognitive assessment in the evaluation of the clinical status of these patients, and have potential therapeutic implications.
... The distinction appears to constitute a useful paradigm for examining the psychological, computational, and neural underpinnings of language, even though the exact mechanisms underlying regular and irregular morphology are still not resolved [1][2][3]55,[58][59]. The use of regular and irregular forms may also facilitate the creation of targeted sensitive language tests that could have potential diagnostic value in various neurological and psychiatric disorders (e.g., Huntington's, Parkinson's, and Alzheimer's diseases, carotid stenosis) [10,11,12]. ...
... Most have used receptive tasks (e.g., priming), though these have been limited to plural inflection (and have all been published in Hungarian, decreasing their accessibility to a broad readership) [25,26,27]. We are aware of four studies that have examined the regular/irregular contrast with production tasks [10,11,28,29,30]. However, all four tested patient groups (Huntington's disease, carotid stenosis, Williams syndrome, and Specific Language Impairment), and had relatively small (maximum 30) subject numbers for both patients and controls. ...
... The regular advantage observed here is also in line with the pattern found for the normal controls (and patients) in both previous studies of Hungarian plural production in adults [10,11] (the other two production studies examined children [28,30]). Note that in one of the two studies of adults both regular and irregular plurals were produced at ceiling by the controls [10], though not by the patients, who showed the expected pattern of worse performance on irregulars. ...
The contrast between regular and irregular inflectional morphology has been useful in investigating the functional and neural architecture of language. However, most studies have examined the regular/irregular distinction in non-agglutinative Indo-European languages (primarily English) with relatively simple morphology. Additionally, the majority of research has focused on verbal rather than nominal inflectional morphology. The present study attempts to address these gaps by introducing both plural and past tense production tasks in Hungarian, an agglutinative non-Indo-European language with complex morphology. Here we report results on these tasks from healthy Hungarian native-speaking adults, in whom we examine regular and irregular nominal and verbal inflection in a within-subjects design. Regular and irregular nouns and verbs were stem on frequency, word length, and phonological structure, and both accuracy and response times were acquired. The results revealed that the regular/irregular contrast yields similar patterns in Hungarian, for both nominal and verbal inflection, as in previous studies of non-agglutinative Indo-European languages: the production of irregular inflected forms was both less accurate and slower than of regular forms, both for plural and past-tense inflection. The results replicate and extend previous findings to an agglutinative language with complex morphology. Together with previous studies, the evidence suggests that the regular/irregular distinction yields a basic behavioral pattern that holds across language families and linguistic typologies. Finally, the study sets the stage for further research examining the neurocognitive substrates of regular and irregular morphology in an agglutinative non-Indo-European language.
... Likewise, as we observed, cognitive performance in multiple cognitive functions has been shown to be lower in subjects with stenosis [55,56]. In studies that compared cognitive performance of subjects with and without stenosis, subjects with stenosis had a worse performance in attention, psychomotor speed, memory, motor skills [57], visuospatial abilities and language [58,59]. ...
Vascular pathology and genetic markers such as apolipoprotein E allele ε4 (ApoE ε4) are risk factors for the progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD). In Panama, a high prevalence of vascular risk factors and an increase in the aging population, generate the need to investigate biomarkers using specific, sensitive, non-invasive and cost-efficient methods that could be used in primary care. The main objective of this study was to explore the association between vascular biomarkers such as intima-media thickness (IMT) and stenosis, ApoE ε4 and cognitive function in a sample of older adults, including healthy controls (n = 41), MCI (n = 33), and AD (n = 12). A descriptive and cross-sectional study was conducted. Participants were part of the Panama Aging Research Initiative (PARI), the first prospective study in aging in Panama. Assessments included a neuropsychological battery, ApoE ε4 genotyping and a Doppler ultrasound of the left carotid artery to examine the presence of vascular risk factors. Neuropsychological tests were combined to form six cognitive domains: Global cognition, language, visuospatial abilities, learning and memory, attention and executive functions. Multivariable analyses (using age, education, and ApoE ε4 expression as covariates) were conducted. Participants with increased IMT showed poorer performance in memory and those with carotid stenosis showed poorer performance in language, visuospatial abilities and attention, independent of age, education or ApoE ε4 expression. The results support the use of vascular markers in cognitive assessments of aged individuals.
Objective
The aim was to evaluate the relationship between asymptomatic carotid stenosis (ACS) of any severity and cognitive impairment and to determine whether there is evidence supporting an aetiological role for ACS in the pathophysiology of cognitive impairment.
Data sources
PubMed/Medline, Embase, Scopus, and the Cochrane library.
Review methods
This was a systematic review (35 cross sectional or longitudinal studies)
Results
Study heterogeneity confounded data interpretation, largely because of no standardisation regarding cognitive testing. In the 30 cross sectional and six longitudinal studies (one included both), 33/35 (94%) reported an association between any degree of ACS and one or more tests of impaired cognitive function (20 reported one to three tests with poorer cognition; 11 reported four to six tests with poorer cognition, while three studies reported seven or more tests with poorer cognition). There was no evidence that ACS caused cognitive impairment via silent cortical infarction, or via involvement in the pathophysiology of lacunar infarction or white matter hyperintensities. However, nine of 10 studies evaluating cerebral vascular reserve (CVR) reported that ACS patients with impaired CVR were significantly more likely to have cognitive impairment and that impaired CVR was associated with worsening cognition over time. Patients with severe ACS but normal CVR had cognitive scores similar to controls.
Conclusion
Notwithstanding significant heterogeneity within the constituent studies, which compromised overall interpretation, 94% of studies reported an association between ACS and one or more tests of cognitive impairment. However, “significant association” does not automatically imply an aetiological relationship. At present, there is no clear evidence that ACS causes cognitive impairment via silent cortical infarction (but very few studies have addressed this question) and no evidence of ACS involvement in the pathophysiology of white matter hyperintensities or lacunar infarction. There is, however, better evidence that patients with severe ACS and impaired CVR are more likely to have cognitive impairment and to suffer further cognitive decline with time.
Language comprises a lexicon for storing words and a grammar for generating rule-governed forms. Evidence is presented that the lexicon is part of a temporal-parietalhnedial-temporal "declarative memory" system and that granlmatical rules are processed by a frontamasal-ganglia "procedural" system. Patients produced past tenses of regular and novel verbs (looked and plagged), which require an -ed-suffixation rule, and irregular verbs (dug), which are retrieved from memory. Word-finding difficulties in posterior aphasia, and the general declarative memory impairment in Alzheimer's disease, led to more errors with irregular than regular and novel verbs. Grammatical difficulties in anterior aphasia, and the general impairment of procedures in Parkinson's disease, led to the opposite pattern. In contrast to the Parkinson's patients, who showed sup pressed motor activity and rule use, Huntington's disease patients showed excess motor activity and rule use, underscoring a role for the basal ganglia in grammatical processing.
Our research group adapted the well-known English Listening Span task to the Hungarian language to test working memory capacity in Hungarian. The English version of the task has been widely used to test age related changes and to map pathological variations of working memory. One of the great advantages of this task is that it can be used with a much larger target group than the previous tests, because reading or writing skills are not requisites for testing. Furthermore, it can be a useful diagnostic tool in assessing learning disabilities and other cognitive impairments. The Hungarian Listening Span task and data is presented for the first time.
Williams syndrome (WMS), a rare neurogenetic disorder, has been in the forefront of research in cognitive psychology for the last 10 years. Studies of grammatical development in 14 Hungarian WMS children are presented: they were examined on tasks testing regular and irregular morphology; measures of digit span were also obtained. Results on the production of accusative and plural forms confirmed for Hungarian that regardless of the frequency of the item, inflected forms of irregulars are harder to produce, and often regularized in WMS, revealing a dissociation between the rules of grammar vs. the mental lexicon. Overall performance on the morphology task is associated with the capacity of phonological short-term memory: subjects with higher span perform better on both tasks. The specification of the surprisingly close relation of phonological short-term memory with the linguistic measures awaits further study.
Transient ischemic attacks (TIAs) often herald a stroke, but little is known about the acute natural history of TIAs. Our objective was to quantify the early risk of stroke after a TIA in patients with internal carotid artery disease.
Using patient data from the medical arm of the North American Symptomatic Carotid Endarterectomy Trial, we calculated the risk of ipsilateral stroke in the territory of the symptomatic internal carotid artery within 2 and 90 days after a first-recorded hemispheric TIA. We also studied similar outcomes among patients in the trial who had a first-recorded completed hemispheric stroke.
For patients with a first-recorded hemispheric TIA (n = 603), the 90-day risk of ipsilateral stroke was 20.1% (95% confidence interval [CI] 17.0%-23.2%), higher than the 2.3% risk (95% CI 1.0%-3.6%) for patients with a hemispheric stroke (n = 526). The 2-day risks were 5.5% and 0.0%, respectively. Patients with more severe stenosis of the internal carotid artery (> 70%) appeared to be at no greater risk of stroke than patients with lesser degrees of stenosis (adjusted hazard ratio 1.1, 95% CI 0.7-1.7). Infarct on brain imaging (adjusted hazard ratio 2.1, 95% CI 1.5-3.0) and the presence of intracranial major-artery disease (adjusted hazard ratio 1.9, 95% CI 1.3-2.7) doubled the early risk of stroke in patients with a hemispheric TIA.
Patients who had a hemispheric TIA related to internal carotid artery disease had a high risk of stroke in the first few days after the TIA. Early risk of stroke was not affected by the degree of internal carotid artery stenosis.
The role of the basal ganglia, and more specifically of the striatum, in language is still debated. Recent studies have proposed that linguistic abilities involve two distinct types of processes: the retrieving of stored information, implicating temporal lobe areas, and the application of combinatorial rules, implicating fronto-striatal circuits. Studies of patients with focal lesions and neurodegenerative diseases have suggested a role for the striatum in morphological rule application, but functional imaging studies found that the left caudate was involved in syntactic processing and not morphological processing. In the present study, we tested the view that the basal ganglia are involved in rule application and not in lexical retrieving in a model of striatal dysfunction, namely Huntington's disease at early stages. We assessed the rule-lexicon dichotomy in the linguistic domain with morphology (conjugation of non-verbs and verbs) and syntax (sentence comprehension) and in a non-linguistic domain with arithmetic operations (subtraction and multiplication). Thirty Huntington's disease patients (15 at stage I and 15 at stage II) and 20 controls matched for their age and cultural level were included in this study. Huntington's disease patients were also assessed using the Unified Huntington's Disease Rating Scale (UHDRS) and MRI. We found that early Huntington's disease patients were impaired in rule application in the linguistic and non-linguistic domains (morphology, syntax and subtraction), whereas they were broadly spared with lexical processing. The pattern of performance was similar in patients at stage I and stage II, except that stage II patients were more impaired in all tasks assessing rules and had in addition a very slight impairment in the lexical condition of conjugation. Finally, syntactic rule abilities correlated with all markers of the disease evolution including bicaudate ratio and performance in executive function, whereas there was no correlation with arithmetic and morphological abilities. Together, this suggests that the striatum is involved in rule processing more than in lexical processing and that it extends to linguistic and non-linguistic domains. These results are discussed in terms of domain-specific versus domain-general processes of rule application.
A technique for studying the relationship between brain and language, which involves correlating scores on two continuous variables, signal intensity across the entire brains of brain-damaged patients and behavioral priming scores, was used to investigate a central issue in cognitive neuroscience: Are the components of the neural language system organized as a single undifferentiated process, or do they respond differentially to different types of linguistic structure? Differences in lexical structure, in the form of the regular and irregular past tense, have proven to be critical in this debate by contrasting a highly predictable rule-like process (e.g., jump-jumped) with an unpredictable idiosyncratic process typified by the irregulars (e.g., think-thought). The key issue raised by these contrasts is whether processing regular and irregular past tense forms differentially engages different aspects of the neural language system or whether they are processed within a single system that distinguishes between them purely on the basis of phonological and semantic differences. The correlational analyses provide clear evidence for a functional differentiation between different brain regions associated with the processing of lexical form, meaning, and morphological structure.
• morphology
• neuroscience
The Corsi Block-Tapping Task measures visuospatial short-term and working memory, but a standardized backward condition is lacking. The authors present a standardized backward procedure that was examined in 246 healthy older adults (ages 50 to 92), comparing the results with the Digit Span subtest of the Wechsler Adult Intelligence Scale--Third Edition. Principal component analysis resulted in a two-factor model, dissociating a verbal and a spatial working-memory factor. Also the Corsi backward is not more difficult than the Corsi forward, in contrast to the Digit Span backward that is more difficult than the Digit Span forward. This may suggest that the Corsi Block-Tapping Task backward task relies on processing within working-memory's slave systems, whereas the Digit Span backward also relies on the central executive component of working memory. Finally, regression-based normative data and cutoff scores for older adults are presented for use in clinical practice.
Factors Influencing Errors with Inflectional MorphologyAccounting for the DeficitsThe Relevance of Inflectional Disorders for Linguistic TheoryConclusion
References
It has been postulated that up to 11 million "silent" strokes occur annually. While these patients are without classic neurologic deficits, they may exhibit cognitive decline. In this study, we examine the cognitive function of patients with carotid stenosis. Additionally, we evaluate a noninvasive measure of strain in pulsating carotid artery plaques to determine its ability to predict cognitive decline.
We administered the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to 44 patients with carotid stenosis. All patients had stenosis meeting NASCET or ACAS criteria for endarterectomy, and were classified as symptomatic or asymptomatic as defined by these publications. Age-adjusted scores for each of the 5 RBANS domains (immediate memory, visuospatial ability, language, attention, and delayed memory) were compared between symptomatic and asymptomatic patients. Mean score for each of the 5 domains was then compared to all other domains, regardless of symptom status. From this cohort, 23 patients underwent assessment of carotid plaque strain by tracking displacements in ultrasound radiofrequency data to estimate axial and principal strains over the cardiac cycle.
Thirty symptomatic and 14 asymptomatic patients were studied. Visuospatial scores were significantly lower than any other domain regardless of symptoms (p<0.05 for all pairwise comparisons). No other domain score was significantly different from any other. In the language domain, asymptomatic patients scored significantly higher than symptomatic patients (p<0.05. For all other domains, no difference was found. Asymptomatic patients showed a relationship between plaque strain and immediate memory (r=-.61, p=ns). Left carotid disease was associated with poorer performance across multiple cognitive domains with increasing accumulated strain. This was not seen in right carotid disease.
Patients with large carotid plaques (>70% stenosis) exhibit significant difficulties in mental status whether classically symptomatic or asymptomatic. While language deficits may be a non-specific marker for stroke symptoms, visuospatial deficits are seen before classic symptoms, suggesting that carotid disease may become symptomatic earlier and more subtly than previously suspected. Abnormal strain distribution with pulsation may be related to cognition.
Studies of English have shown that temporal-lobe patients, including those with Alzheimer's disease, are spared at processing real and novel regular inflected forms (e.g., walk-->walked; blick-->blicked), but impaired at real and novel irregular forms (e.g., dig-->dug; spling-->splang). Here we extend the investigation cross-linguistically to the more complex system of Italian verbal morphology, allowing us to probe the generality of the previous findings in English, as well as to test different explanatory accounts of inflectional morphology. We examined the production of real and novel regular and irregular past-participle and present-tense forms by native Italian-speaking healthy control subjects and patients with probable Alzheimer's disease. Compared to the controls, the patients were impaired at inflecting real irregular verbs but not real regular verbs both for past-participle and present-tense forms, but were not impaired at real regular verbs either for past-participle or present-tense forms. For novel past participles, the patients exhibited this same pattern of impaired production of class II (irregular) forms but spared class I (regular) production. In the present-tense, patients were impaired at the production of class II forms (which are regular in the present-tense), but spared at production of class I (regular) forms. Contrary to the pattern observed in English, the errors made by the patients on irregulars did not reveal a predominance of regularization errors (e.g., dig-->digged). The findings thus partly replicate prior findings from English, but also reveal new patterns from a language with a more complex morphological system that includes verb classes (which are not possible to test in English). The demonstration of an irregular deficit following temporal-lobe damage in a language other than English reveals the cross-linguistic generality of the basic effect, while also elucidating important language-specific differences in the neurocognitive basis of regular and irregular morphological forms.
While stroke is a known cause of a cognitive impairment, the relationship between a carotid artery stenosis and the cognitive function in individuals without a history of stroke is less clear. A number of risk factors for vascular disease are related to a cognitive impairment. Hypertension, diabetes mellitus, cigarette smoking, and dyslipidemia are also associated with an increased risk of carotid artery disease. Some studies have suggested that a stenosis of the internal carotid artery may be an independent risk factor for a cognitive impairment. A high-grade stenosis of the internal carotid artery may be associated with a cognitive impairment even without evidence of infarction on magnetic resonance imaging. On the other hand, it is fairly common that patients display a normal cognition despite severe carotid artery disease, highlighting the important role of an efficient collateral blood supply. The possible pathomechanisms of a cognitive impairment include silent embolization and hypoperfusion. Carotid endarterectomy or stenting may lead to a decline in the cognitive function in consequence of microembolic ischemia or intraprocedural hypoperfusion. Conversely, perfusion restoration could improve a cognitive dysfunction that might have occurred from a state of chronic hypoperfusion. It is unclear whether these complex interactions ultimately result in a net improvement or a deterioration of the cognitive function. The evidence available at present does not seem strong enough to include consideration of a loss of cognition as a factor in determining the balance of the risks and benefits of therapy for a carotid stenosis.
To better define the hemodynamic significance of internal carotid artery stenosis, intraoperative electromagnetic blood flow measurements were taken in 47 patients before and after carotid endarterectomy. When the ratio of pre- to postendarterectomy blood flew (Qpre/Qpost = Y) is compared to the fractional percent of internal carotid artery stenosis (X), the linear regression lines for the 25 arteries with Qpre/Qpost less than 0.70 are Y = -2.67 x +2.59 and Y = -10.10 x +10.06, respectively, for diameter and area stenosis. The intercepts of the regression lines with (a) Qpre/Qpost = 1 (normal blood flow) are 60% diameter and 90% are stenosis, (b) Qpre/Qpost = 0.60 (40% reduction in blood flow) are 75% diameter and 94% are stenosis and (c) with Qpre/Qpost = 0.36 (64% reduction in blood flow) are 84% diameter and 96% area stenosis. These data indicate that a critical or hemodynamically significant internal carotid artery stenosis may be of a higher grade than previously appreciated and that a stenosis greater than 75% diameter or 94% area may be necessary to symptomatically reduce cerebral blood flow.
This article describes a standardized administration and scoring procedure for the widely used Corsi Block-Tapping Task, designed to assess the visual memory span. This method was applied in a group of healthy participants (n = 70) and a group of patients with cerebral lesions (n = 70), that were categorized on the basis of lesion location (left or right hemisphere, bilateral or subcortical). The percentile distribution as well as cutoff points on the basis of the control data are provided. It was found that 20% of the patients perform in the borderline range on this task, and over 8% have an impaired performance ("retarded"). In addition, right hemisphere patients performed worse than left hemisphere patients. These data show that the Corsi Block-Tapping Task can be effectively used to assess visuospatial short-term memory in patients with brain damage, and is selective for the side of the lesion.
To assess the relationship between asymptomatic carotid stenosis, neuropsychological test performance, and silent MRI lesions.
Performance on several neuropsychological tests was compared in 189 subjects with ultrasound-assessed carotid stenosis and 201 control subjects without carotid stenosis, recruited from a population health study. Subjects with a previous history of stroke were excluded. The test battery included tests of attention, psychomotor speed, memory, language, speed of information processing, motor functioning, intelligence, and depression. Sagittal T1-weighted and axial and coronal T2-weighted spin echo MRI was performed, and presence of MRI lesions (white matter hyperintensities, lacunar and cortical infarcts) was recorded.
Subjects with carotid stenosis had significantly lower levels of performance in tests of attention, psychomotor speed, memory, and motor functioning, independent of MRI lesions. There were no significant differences in tests of speed of information processing, word association, or depression. Cortical infarcts and white matter hyperintensities were equally distributed among persons with and without carotid stenosis. Lacunar infarcts were more frequent in the stenosis group (p = 0.03).
Carotid stenosis was associated with poorer neuropsychological performance. This could not be explained by a higher proportion of silent MRI lesions in persons with asymptomatic carotid stenosis, making it less likely that the cognitive impairment was caused by silent emboli.
Morphology and language disorder Morphological patterns in Hungarian children with Williams syndrome and the rule debates
- M Penke
Penke, M. (2008). Morphology and language disorder. In M. J. Ball (Ed.), Handbook of clinical linguistics (pp. 212–228). Blackwell. Pleh, C., Lukacs, A., & Racsmany, M. (2003). Morphological patterns in Hungarian children with Williams syndrome and the rule debates. Brain and Language, 86(3), 377–383.
A new screening method for Hungarian language impaired children
- C Pléh
- G Palotás
- J Lorik
Pléh, C., Palotás, G., & Lorik, J. (2002). A new screening method for Hungarian language impaired children. Budapest: Akadémiai
(in Hungarian).