Figure 1 - uploaded by Richard A. Armstrong
Content may be subject to copyright.
Section of midbrain of a case of chronic traumatic encephalopathy (CTE) showing tau-immunoreactive pathology (brown immunolabelling) in various nuclei and fibre tracts (CA: cerebral aqueduct, Csp: cortico-spinal tract, FPon: fronto-pontine fibres, ML: medial lemniscus, MLF: medial longitudinal fasciculus, PAG: periqueductal gray, SC: superior colliculus, SCP: superior cerebellar peduncle, SN: substantia nigra, TrN: trochlear nucleus). Pathology is particularly evident in the SC, SN, and TrN. Tau immunohistochemistry (AT8, haematoxylin).
Source publication
Traumatic brain injury (TBI) and its associated concussion are major causes of disability and death. All ages can be affected but children, young adults and the elderly are particularly susceptible. A decline in mortality has resulted in many more individuals living with a disability caused by TBI including those affecting vision. This review descr...
Contexts in source publication
Context 1
... Hence, functional magnetic resonance imaging (fMRI) studies of oculomotor control nuclei during vergence and saccadic eye movement have revealed bilateral signals in control patients originating in the superior colliculus and oculomotor and abducens nuclei, such signals being significantly reduced in chronic TBI. 68 Various pathological changes have also been observed in the midbrain in some cases of CTE affecting the superior colliculus and associated nuclei and in fibre tracts controlling eye movement 125 (Figure 1). In addition, examination of eye movement enables higher cortical functioning and the involvement of many diffuse brain pathways to be assessed. ...
Context 2
... Hence, func- tional magnetic resonance imaging (fMRI) studies of oculomotor control nuclei during vergence and saccadic eye movement have revealed bilateral signals in control patients originating in the superior colliculus and oculomotor and abducens nuclei, such sig- nals being significantly reduced in chronic TBI. 68 Various pathological changes have also been observed in the midbrain in some cases of CTE affecting the superior colliculus and associated nuclei and in fibre tracts controlling eye movement 125 (Figure 1). In addition, examination of eye movement enables higher cortical functioning and the involvement of many diffuse brain pathways to be assessed. ...
Similar publications
The eyes are the first channel used by humans to obtain various types of visual information from the outside world, especially for driver, 80-90% of information is received through eyes in driving. The eye movement behaviors are generally divided into six types, but attention is often paid to fixation, saccade, and smooth pursuit. Therefore, it is...
Eye movements reveal a great wealth of information about the visual system and the brain. Therefore, eye movements can serve as diagnostic markers for various neurological disorders. For an objective analysis, it is crucial to have an automatic and robust procedure to extract relevant eye movement parameters. An essential step towards this goal is...
Significance:
Oculomotor tests in concussion commonly show impairment in smooth pursuit and saccadic function. Honing in on the systems likely to be affected by concussion will streamline use of oculomotor function as a supplemental diagnostic and prognostic tool, as well as improve our understanding of the pathophysiology of concussion.
Purpose:...
To review our studies and “top-down” models of saccadic intrusions and infantile nystagmus syndrome with the aim of hypothesizing areas of cerebellar connections controlling parts of the ocular motor subsystems involved in both types of function and dysfunction. The methods of eye-movement recording and modeling are described in detail in the cited...
Mild traumatic brain injury (mTBI), or concussion, occurs following a direct or indirect force to the head that causes a change in brain function. Many neurological signs and symptoms of mTBI can be subtle and transient, and some can persist beyond the usual recovery timeframe, such as balance, cognitive or sensory disturbance that may pre-dispose...
Citations
... For example, both traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) create profound effects on the structure and function of the brain, influencing how individuals process and respond to visual stimuli. TBI, often resulting from sudden impacts to the head, can lead to defects in primary vision, eye movement, saccadic and smooth pursuit movements, motion vision, and visuo-spatial function (Armstrong, 2018). The visual reaction time of patients with head injuries is slower than that of healthy control individuals (Levin, 1998). ...
Introduction
Studies suggest a relationship between the emotional evocativeness of visual imagery and viewer responses, however, there is limited understanding of these associations, especially as they relate to viewers’ personal experiences of adversities.
Methods
In this exploratory study, we examined the relationship between the visual content of mask images and viewers’ responses. In an online survey 699 participants (of n = 1,010 total initial participants) rated 98 masks based on valence, arousal, and personal relevance and completed the Life Events Checklist. The masks included those created by service members (SMs) with traumatic brain injury (TBI), and post-traumatic stress disorder (PTSD), depicting physical, psychological, and moral injuries and matched neutral masks created by creative arts therapists and arts in health scholars.
Findings
The findings indicated that responses to mask image content (traumatic versus neutral) were associated with viewers’ personal history of adversity and trauma. Specifically, images representing injury/trauma provoked stronger reactions on valence and arousal than neutral images. Moreover, participants with personal histories of trauma had heightened emotional responses to distressing imagery.
Discussion
These findings have implications for art therapists as well as for clinical and general populations in that these results highlight the potential impact of distressing imagery particularly for individuals with personal histories of experiencing or witnessing traumatic events.
... It has been suggested that axonal damage at the brainstem can elicit eye movement abnormalities resulting in delayed response to stimuli and during pursuit tasks (18). The neuro-ophthalmological function is a pivotal marker for brain damage as it seems sensitive to traumatic and mild traumatic brain injuries (1,7,30). The impairment of neuro-ophthalmological function in patients following a concussion correlates with the severity of concussion symptoms (5,12,19,29). ...
... V isual problems following acquired brain injury (ABI) are a complex and multifaceted condition (1) that poses significant challenges to individuals (2), healthcare professionals, and society (3)(4)(5)(6). Various aspects of visual processing lead to a wide range of visual impairments (7), including reduced visual acuity, visual field defects, oculomotor dysfunction, binocular vision abnormalities, and higher-level visual processing deficits (8). The prevalence of overall visual problems after ABI has been estimated to range from 54% to 73% (9,10), depending on the type of problem, time of assessment, and assessment methods used. ...
Objectives: To explore current hospital practice in relation to the assessment of vision problems in patients with acquired brain injury. Design: A survey study. Subjects: A total of 143 respondents from hospital settings, with background in occupational therapy and physical therapy, participated in the survey. Methods: The survey questionnaire, developed collaboratively by Danish and Norwegian research groups, encompassed 22 items categorically covering “Background information”, “Clinical experience and current practice”, “Vision assessment tools and protocols”, and “Assessment barriers”. It was sent out online, to 29 different hospital departments and 18 separate units for occupational therapists and physiotherapists treating patients with acquired brain injury. Results: Most respondents worked in acute or subacute hospital settings. Few departments had an interdisciplinary vision team, and very few therapists had formal education in visual problems after acquired brain injury. Visual assessment practices varied, and there was limited use of standardized tests. Barriers to identifying visual problems included patient-related challenges, knowledge gaps, and resource limitations. Conclusion: The study emphasized the need for enhanced interdisciplinary collaboration, formal education, and standardized assessments to address visual problems after acquired brain injury. Overcoming these challenges may improve identification and management, ultimately contributing to better patient care and outcomes in the future.
... The prevalence of vision impairment in neurodegenerative conditions such as multiple sclerosis, Alzheimer's disease, and Parkinson's disease, has been reported between 1.7-58% [5][6][7]. However, studies often consist of small numbers, with some authors considering visual acuity decline as the only measure of vision impairment [3,5], without considering other visual impairments that may occur following neurological impairment such as, difficulties with visual field loss, ocular motility disorders, and visual perceptual deficits [8,9]. ...
Background
Visual impairment is a common consequence of neurological impairments, and can impact a person’s ability to undertake everyday tasks, affecting their confidence and mental health. Previous qualitative research in the UK has shown inequalities to exist where patients are accessing vision care after stroke, but little is known around the experiences of accessing vision care following other neurological impairments, and a lack of national guidelines prevent standardised care planning. The aim of this qualitative study is to explore the perceptions of vision care after neurological impairment, and to identify possible inequalities and support mechanisms, where it has been possible to access vision care.
Methods
University ethical approval was obtained, and adults with a visual impairment as a result of a neurological impairment were offered an in-depth interview to explore their vision care experiences. Data were collected between April and November 2021 and analysed using iterative, thematic analysis (TA), informed by a social constructionist ideology.
Results
Seventeen participants were recruited. Three overarching themes were conceptualised in relation to the participants’ perception of vision care: Making sense of the visual impairment; The responsibility of vision care; and Influential factors in care quality perception.
Conclusion
Inequalities were noted by participants, with most reporting a lack of suitable vision care offered as part of their neurological rehabilitation. Participants were thus burdened with the task of seeking their own support online, and encountered inaccurate and worrying information in the process. Participants noted changes in their identity, and the identity of their family carers, as they adjusted to their vision loss. The findings from this research highlight a need for clinicians to consider the long-term impact of vision loss after neurological impairment, and ensure patients are provided with adequate support and information, and appropriate referral pathways, alleviating this patient burden.
... Several studies have reported prolonged visual symptoms in PCS. 34,36,41 It has been hypothesized that with the heavy burden of the visual sensory system, some other common persistent symptoms, such as headache and dizziness, may result from mismatched perceptions between central and peripheral visual processing, highlighting potential oculomotor and neuro-visual dysfunction. 42 Standard vision training therapy conducted by an optometrist is usually indicated for strabismus, phorias, and binocular vision deficiencies, and more often, it uses established oculomotor methods. ...
Sports-related concussions (SRC) are a common injury among athletes. Despite our growing understanding of concussion pathophysiology, comprehensive rehabilitation programs remain a clinical challenge. The accepted view of SRC rehabilitation emphasizes physical and cognitive rest. However, some conflicting studies report rest may facilitate prolonged symptoms. In this review article, we report on alternative SRC rehabilitation strategies to address the complex symptom variations, including physical activity, neuro-visual training, vestibular training, music therapy, speech-language therapy, and hyperbaric oxygen chamber therapy. The mass of published works supports the utility of these alternative therapies to aid recovery, but more research is vital to clarifying these relationships. In this review, we explore the relationships between symptoms and therapies. As there is a growing body of evidence to support these alternative therapies, many questions remain when concerning the role these alternative methods play in the bigger picture of standardizing a thorough SRC rehabilitation program.
... Another study reported ongoing decline in retinal nerve fiber layer thickness in a longitudinal cohort following patients over several years [41]. Visual problems associated with TBI are heterogeneous and can vary depending on the type of injury and its severity [46], but vision impairment represents an important functional outcome that should be included in preclinical and clinical studies. In this study we used a moderate to severe model of TBI consisting of a right-sided controlled cortical impact to the dura mater. ...
... It is unclear how delayed administration of a complement inhibitor would impact visual outcomes. However, the rate of disability, and particularly visual disability is quite high after TBI [46], which means that many individuals will have missed the window for acute complement inhibitor treatment. We have previously reported on inflammatory outcomes with delayed treatment paradigms in which a complement inhibitor was administered beginning either at 7, 28 or 56 days after CCI [10,11]. ...
... The mouse has roughly 90% of RGC axons cross at the optic commissure, whereas in humans it is roughly 50% [54]. Therefore, the visual phenotype we observed in the mouse more severely affected a single eye and visual field, whereas in humans it is often a hemianopia, which affects vision in both eyes [5,46]. The human dLGN is also organized into eye-specific laminae that project to specific layers of the V1 visual cortex, whereas the mouse dLGN is not laminar and inputs are dominated by projections from the contralateral eye [54,55]. ...
Background
Traumatic brain injury (TBI) is associated with the development of visual system disorders. Visual deficits can present with delay and worsen over time, and may be associated with an ongoing neuroinflammatory response that is known to occur after TBI. Complement system activation is strongly associated with the neuroinflammatory response after TBI, but whether it contributes to vision loss after TBI is unexplored.
Methods
Acute and chronic neuroinflammatory changes within the dorsal lateral geniculate nucleus (dLGN) and retina were investigated subsequent to a moderate to severe murine unilateral controlled cortical impact. Neuroinflammatory and histopathological outcomes were interpreted in the context of behavioral and visual function data. To investigate the role of complement, cohorts were treated after TBI with the complement inhibitor, CR2-Crry.
Results
At 3 days after TBI, complement component C3 was deposited on retinogeniculate synapses in the dLGN both ipsilateral and contralateral to the lesion, which was reduced in CR2-Crry treated animals. This was associated with microglia morphological changes in both the ipsilateral and contralateral dLGN, with a less ramified phenotype in vehicle compared to CR2-Crry treated animals. Microglia in vehicle treated animals also had a greater internalized VGlut2 + synaptic volume after TBI compared to CR2-Crry treated animals. Microglia morphological changes seen acutely persisted for at least 49 days after injury. Complement inhibition also reduced microglial synaptic internalization in the contralateral dLGN and increased the association between VGLUT2 and PSD95 puncta, indicating preservation of intact synapses. Unexpectedly, there were no changes in the thickness of the inner retina, retinal nerve fiber layer or retinal ganglion layer. Neuropathological changes in the dLGN were accompanied by reduced visual acuity at subacute and chronic time points after TBI, with improvement seen in CR2-Crry treated animals.
Conclusion
TBI induces complement activation within the dLGN and promotes microglial activation and synaptic internalization. Complement inhibition after TBI in a clinically relevant paradigm reduces complement activation, maintains a more surveillance-like microglia phenotype, and preserves synaptic density within the dLGN. Together, the data indicate that complement plays a key role in the development of visual deficits after TBI via complement-dependent microglial phagocytosis of synapses within the dLGN.
... Given that approximately half of the brain's neural pathways are dedicated to vision, the visual system is particularly vulnerable to shearing injury following mTBI 11 . As a result, considerable attention has been drawn to a variety of visual impairments associated with mild traumatic brain injury (mTBI) [12][13][14] , including defects in visual acuity 15 , blurred vision 12 , deficits in accommodation 16 and binocular disparity 17 . However, little attention has been given to the perception of visual stimuli or the integration of visual information following mTBI. ...
Perceptual grouping is impaired following mild traumatic brain injury (mTBI). This may affect visual size perception, a process influenced by perceptual grouping abilities. We conducted two experiments to evaluate visual size perception in people with self-reported history of mTBI, using two different size-contrast illusions: the Ebbinghaus Illusion (Experiment 1) and the Müller-Lyer illusion (Experiment 2). In Experiment 1, individuals with mTBI and healthy controls were asked to compare the size of two target circles that were either the same size or different sizes. The target circles appeared by themselves (no-context condition), or were surrounded by smaller or larger circles (context condition). Similar levels of accuracy were evident between the groups in the no-context condition. However, size judgements by mTBI participants were more accurate in the context condition, suggesting that they processed the target circles separately from the surrounding circles. In Experiment 2, individuals with mTBI and healthy controls judged the length of parallel lines that appeared with arrowheads (context condition) or without arrowheads (no context condition). Consistent with Experiment 1, size judgements by mTBI participants were more accurate than size judgements by control participants in the context condition. These findings suggest that mTBI influences size perception by impairing perceptual grouping of visual stimuli in near proximity.
... Taken together with our previous data analyzing microglial activity within TBI lesion penumbra (REF), our ndings suggest that aberrant synaptic phagocytosis occurring within the dLGN may contribute to vision loss, which can be reversed with complement C3 inhibition. There are currently no therapeutic interventions for TBI, and the only visual interventions available involve optomotor rehabilitation, tinted or prismatic lenses, or behavioral adaptations (32). There is currently a C1-inhibitor being investigated in a clinical trial for TBI (CIAO@TBI), and although it does not speci cally include visual outcomes in its primary or secondary endpoints, it includes quality of life score, which may partially re ect improved visual outcomes (44). ...
Background:Traumatic brain injury (TBI) is associated with the development of visual system disorders. Visual deficits can present with delay and worsen over time, and may be associated with an ongoing neuroinflammatory response that is known to occur after TBI. Complement activation is strongly associated with the neuroinflammatory response after TBI, but whether it contributes to vision loss after TBI is unexplored.
Methods: Acute and chronic neuroinflammatory changes within the dorsal lateral geniculate nucleus (dLGN) and retina were investigated subsequent to murine controlled unilateral cortical impact. Neuroinflammatory and histopathological data were interpreted in the context of behavioral and visual function data. To investigate the role of complement, cohorts were treated after TBI with the complement inhibitor, CR2-Crry.
Results: At 3 days after TBI, complement C3 was deposited on retinogeniculate synapses in the dLGN both ipsilateral and contralateral to the lesion, which was reduced in CR2-Crry treated animals. This was associated with microglia morphological changes in both the ipsilateral and contralateral dLGN, with a more amoeboid phenotype in vehicle compared to CR2-Crry treated animals. Microglia in vehicle treated animals also had a greater internalized VGlut2+ synaptic volume after TBI compared to CR2-Crry treated animals. Microglia morphological changes seen acutely persisted for at least 49 days after injury. Complement inhibition also reduced microglial synaptic internalization in the contralateral dLGN and increased the association between VGLUT2 and PSD95 puncta, indicating preservation of intact synapses. Unexpectedly, there were no changes in the thickness of the inner retina, retinal nerve fiber layer or retinal ganglion layer. Pathologies were accompanied by reduced visual acuity at subacute and chronic time points after TBI, with improvement seen in CR2-Crry treated animals.
Conclusion:TBI induces complement activation within the dLGN and promotes microglial activation and synaptic internalization. Complement inhibition after TBI in a clinically relevant paradigm reduces complement activation, maintains a more surveillance-like microglia phenotype, and preserves synaptic density within the dLGN. Together, the data indicate that complement plays a key role in the development of visual deficits after TBI via complement-dependent microglial phagocytosis of synapses within the dLGN.
... Traumatic brain injury (TBI) is a leading cause of morbidity and disability across multiple domains (1), including psychiatric health, pain, cognition, and somatic complications involving cardiovascular, respiratory, endocrine, urinary, visual, and gastrointestinal systems (1)(2)(3)(4)(5)(6)(7)(8). Consequently, individuals who sustained a TBI are reported to have high rates of medication use, and studies show that 45-85% of TBI patients are prescribed psychotropic and pain medications (9)(10)(11)(12)(13)(14)(15)(16)(17). ...
... We classified medications by the Anatomical Therapeutic Chemical (ATC) code that is a globally recognized system for classifying and categorizing pharmaceutical substances based on their therapeutic and chemical properties. We examined a wide spectrum of non-psychotropic medications prescribed to address pain and somatic complications involving cardiovascular, respiratory, endocrine, urinary, visual, and gastrointestinal systems (1)(2)(3)(4)(5)(6)(7)(8). ...
... TBI patients still presented an increased risk of polypharmacy after adjustments for age, sex, and pre-TBI medication use. TBI patients may experience a variety of physical health problems after their injury, including motor impairment, chronic pain, hormonal imbalance, cardiovascular conditions, digestive issues, and sleep disturbances (1)(2)(3)(4)(5)(6)(7)(8), that may lead to an overall decline in function. Management of these problems could lead to the unintended use of multiple medications due to separate treatment settings and guidelines (34). ...
Introduction
Traumatic brain injury (TBI) is associated with health problems across multiple domains and TBI patients are reported to have high rates of medication use. However, prior evidence is thin due to methodological limitations. Our aim was thus to examine the use of a wide spectrum of medications prescribed to address pain and somatic conditions in a population-based cohort of TBI patients, and to compare this to a sex- and age-matched cohort. We also examined how patient factors such as sex, age, and TBI severity were associated with medication use.
Methods
We assessed Swedish nationwide registers to include all individuals treated for TBI in hospitals or specialist outpatient care between 2006 and 2012. We examined dispensed prescriptions for eight different non-psychotropic medication classes for the 12 months before, and 12 months after, the TBI. We applied a fixed-effects model to compare TBI patients with the matched population cohort. We also stratified TBI patients by sex, age, TBI severity and carried out comparisons using a generalized linear model.
Results
We identified 239,425 individuals with an incident TBI and 239,425 matched individuals. TBI patients were more likely to use any medication [Odds ratio (OR) = 2.03, 95% Confidence Interval (CI) = 2.00–2.05], to present with polypharmacy (OR = 1.96, 95% CI = 1.90–2.02), and to use each of the eight medication classes before their TBI, as compared to the matched population cohort. Following the TBI, TBI patients were more likely to use any medication (OR = 1.83, 95% CI = 1.80–1.86), to present with polypharmacy (OR = 1.74, 95% CI = 1.67–1.80), and to use all medication classes, although differences were attenuated. However, differences increased for antibiotics/antivirals (OR = 2.02, 95% CI = 1.99–2.05) and NSAIDs/antirheumatics (OR = 1.62, 95% CI = 1.59–1.65) post-TBI. We also found that females and older patients were more likely to use medications after their TBI than males and younger patients, respectively. Patients with more severe TBIs demonstrated increased use of antibiotics/ antivirals and NSAIDs/antirheumatics than those with less severe TBIs.
Discussion
Taken together, our results point to poor overall health in TBI patients, suggesting that medical follow-up should be routine, particularly in females with TBI, and include a review of medication use to address potential polypharmacy.
... Sometimes axonal disruption in the corpus collosum and blood brain barrier damage can also lead to such defects. 37 For hearing ability, BERA and PTA had almost the same score except for price per test per patient and the wide usage in a clinical setup for the latter. While the AUC for both fell between 0.6 and 0.8 20,22 and the accuracy reported was 90-100%. ...
Objective
To identify the most appropriate tools to measure functions of the brain that can be utilized in the clinical setups of developing countries.
Methods
This qualitative research with a three-step approach was carried out from January 2022 to May 2022 at the Institute of Basic Medical Sciences, Khyber Medical University, Pakistan. Firstly, literature was searched to identify main brain faculties, then interviews were conducted with regional field experts to identify appropriate scales for the selected functions. Lastly a rubric was filled using interview transcripts and literature.
Results
The identified functions were vision, hearing, cognition, motor and emotions. Based on the rubric the best tests were visual fields (17/24), pure tone audiometry (16/24), Mini-Mental State Exam (20/24), Trait Emotional Intelligence Questionnaire (18/24), Romberg’s test (19/24) and Manual Muscle Testing (18/24).
Conclusion
The clinicians in developing countries can utilize the visual fields, pure tone audiometry, Mini-Mental State Exam, Trait Emotional Intelligence Questionnaire, Romberg’s test and Manual Muscle Testing for most efficient, feasible, accurate and cost-effective measurement of brain functions.
