Disorders of vision and visual-perceptual dysfunction

Chaikin, Laurie Ruth

doi:10.1016/b978-0-323-07586-2.00037-6

Cited by 7 publications

(13 citation statements)

References 50 publications

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“…Thirty-seven of 74 (50%) had near point of convergence >12.7 cm at baseline (48), and this rate in those above 45 years old was 75%. None were rated “impaired” by the Berg Balance Scale.…”

Section: Resultsmentioning

confidence: 99%

Comprehensive Evaluation of Healthy Volunteers Using Multi-Modality Brain Injury Assessments: An Exploratory, Observational Study

et al. 2018

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Introduction: Even though mild traumatic brain injury is common and can result in persistent symptoms, traditional measurement tools can be insensitive in detecting functional deficits after injury. Some newer assessments do not have well-established norms, and little is known about how these measures perform over time or how cross-domain assessments correlate with one another. We conducted an exploratory study to measure the distribution, stability, and correlation of results from assessments used in mild traumatic brain injury in healthy, community-dwelling adults.Materials and Methods: In this prospective cohort study, healthy adult men and women without a history of brain injury underwent a comprehensive brain injury evaluation that included self-report questionnaires and neurological, electroencephalography, sleep, audiology/vestibular, autonomic, visual, neuroimaging, and laboratory testing. Most testing was performed at 3 intervals over 6 months.Results: The study enrolled 83 participants, and 75 were included in the primary analysis. Mean age was 38 years, 58 were male, and 53 were civilians. Participants did not endorse symptoms of post-concussive syndrome, PTSD, or depression. Abnormal neurological examination findings were rare, and 6 had generalized slowing on electroencephalography. Actigraphy and sleep diary showed good sleep maintenance efficiency, but 21 reported poor sleep quality. Heart rate variability was most stable over time in the sleep segment. Dynavision performance was normal, but 41 participants had abnormal ocular torsion. On eye tracking, circular, horizontal ramp, and reading tasks were more likely to be abnormal than other tasks. Most participants had normal hearing, videonystagmography, and rotational chair testing, but computerized dynamic posturography was abnormal in up to 21% of participants. Twenty-two participants had greater than expected white matter changes for age by MRI. Most abnormal findings were dispersed across the population, though a few participants had clusters of abnormalities.Conclusions: Despite our efforts to enroll normal, healthy volunteers, abnormalities on some measures were surprisingly common.Trial Registration: This study was registered at www.clinicaltrials.gov, trial identifier NCT01925963.

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Section: Resultsmentioning

confidence: 99%

Comprehensive Evaluation of Healthy Volunteers Using Multi-Modality Brain Injury Assessments: An Exploratory, Observational Study

et al. 2018

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“…Difficulty in “maintaining the normal ocular position” may result in disconjugate eye movement (eyes do not move in the same direction and by equal amount) ( 1 , 2 ); strabismus (one eye or both eyes deviate so the eyes are no longer aligned); and/or nystagmus (frequent involuntary oscillations and other random eye movements) ( 1 ). Difficulty with spontaneous and voluntary movement of the eyes appropriately during functional activities may include impairment of (i) saccadic eye movements ( 1 ) [rapid eye movements (400°–600°/s) that shifts the eyes from one target to another] ( 1 , 2 ), (ii) smooth pursuit eye movements [slow movement of the eyes (1°–30°/s) that serve to keep gaze on a moving visual object of interest when the head is stationary] ( 3 – 5 ), (iii) fixation (ability to maintain a steady eye position on a target) ( 1 ), (iv) convergence (the ability to smoothly and automatically turn the eyes in along the midline to observe near objects with single vision) ( 6 ), (v) divergence (to turn the eyes outward for single vision of distant objects) ( 6 ), (vi) vestibulo-ocular reflex (to ensure stable images on the retina and clear vision during head movements) ( 1 , 2 , 7 , 8 ), and (vii) palsy (inability to use the ocular muscles that move the eye horizontally or vertically) ( 1 , 2 ). Ocular motility and the interpretation of the visual input gathered during eye movements are important for aligning and maintaining the body in space which is fundamental to the successful performance of functional tasks in any particular environment ( 9 ).…”

Section: Introductionmentioning

confidence: 99%

“…Visuomotor deficits and visual–perceptual impairments as result of eye movement disorders may affect an individual’s ability to respond to sensory input obtained from the environment and demands of the task. The inability to respond efficiently upon the sensory input from the environment and demands of the task results in a change (decrease) in postural control that leads to increased functional dependence during ADL and disability ( 6 , 10 ). Clinical observations of patients with eye movement disorders following a stroke may include the following ( 1 , 6 ): (1) head turn or head tilt during near (close-up) tasks, (2) avoidance of near (close-up) tasks, (3) seems to look past the observer, (4) closing or covering one eye during conversations and/or activities due to blurred vision or double-vision, (5) squinting, (6) rubs eyes a lot, (7) having difficulty maintaining eye contact, (8) neglecting one side of the body or space during functional activities, (9) bumping into walls or objects during walking or when maneuvering in a wheelchair, (10) appears to misjudge distance due to a loss of depth perception, (11) difficulty with activities of daily living due to poor eye-hand coordination – knocking objects over or missing objects during reaching, (12) “under reaching” or over reaching for objects, (13) decreased attention during conversations and/or activities (patient “day dreams”), (14) losing the place when reading, (15) having difficulty “seeing” with or without glasses, (16) letters jumping around on the page during reading, (17) experiencing eye strain or headaches, (18) portions of the page being missing when reading, (19) objects or portions of objects not being observed, (20) not seeing people or objects approaching suddenly from one side, and (21) having difficulty concentrating on tasks.…”

Section: Introductionmentioning

confidence: 99%

A Cross-sectional Survey and Cross-sectional Clinical Trial to Determine the Prevalence and Management of Eye Movement Disorders and Vestibular Dysfunction in Post-Stroke Patients in the Sub-Acute Phase: Protocol

et al. 2016

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IntroductionVisual impairment, specifically eye movement disorders and vestibular dysfunction may have a negative influence on the functional recovery in post-stroke patients. This type of sensory dysfunction may further be associated with poor functional outcome in patients’ post-stroke.MethodsIn phase 1, a cross-sectional survey (n = 100) will be conducted to determine the prevalence of eye movement disorders and vestibular dysfunction in patients who sustained a stroke. A cross-sectional clinical trial (n = 60) will be conducted during phase 2 of the study to determine the effect of the combination of vestibular rehabilitation therapy (VRT) and visual scanning exercises (VSE) (experimental group) integrated with task-specific activities compared with the effect of task-specific activities as an intervention (control group) on patients who present with eye movement impairment and central vestibular dysfunction post-stroke. An audiologist will assess (a) visual acuity (static and dynamic), (b) nystagmus, (c) saccadic eye movements, (d) smooth pursuit eye movements, (e) vestibulo-ocular reflex, and (f) saccular, utricular, and vestibular nerve function. An independent physiotherapist will assess (1) cognitive function, (2) residual oculomotor visual performance, (3) visual–perceptual system, (4) functional balance, (5) gait, (6) functional ability, (7) presence of anxiety and/or depression, and (8) level of participation in physical activity.Ethics and disseminationEthics approval has been obtained from the Ethics Committee of the Faculty of Health Sciences at the University of Pretoria (UP) (374/2015). The study will be submitted as fulfillment for the PhD degree at UP. Dissemination will include submission to peer-reviewed professional journals and presentation at congresses. Training of rehabilitation team members on the integration of VSE and VRT into task-specific activities in rehabilitation will be done if the outcome of the experimental group’s functional performance is clinically and statistically significantly better than the control group on the Barthel Index.Trial RegistrationPan African Clinical Trials Registry (PACTR201509001223262).

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“…A standard approach to spatial neglect rehabilitation is based upon visual scanning training (Weinberg et al, 1977 ), in which participants are cued to orient toward the contralesional side of space. In patients with spatial neglect, spontaneous saccadic eye movements or head movements are restricted to the ipsilesional visual hemifield and may rarely cross midline (Zoltan, 1996 ; Chaikin, 2007 ). Visual scanning training expands these movements into the contralesional space by repeatedly using cues, such as “point your right (unimpaired) hand to the left side” or “look to the left.” Recent studies have shown that visual scanning exercises increase perceptual processing (Where networks) in neglect patients, thereby leading to better visual function and ability to perform activities of daily living (van Wyk et al, 2014 ).…”

Section: Introductionmentioning

confidence: 99%

Midline Body Actions and Leftward Spatial “Aiming” in Patients with Spatial Neglect

Chaudhari

Pigott

Barrett

2015

Front. Hum. Neurosci.

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Spatial motor–intentional “Aiming” bias is a dysfunction in initiation/execution of motor–intentional behavior, resulting in hypokinetic and hypometric leftward movements. Aiming bias may contribute to posture, balance, and movement problems and uniquely account for disability in post-stroke spatial neglect. Body movement may modify and even worsen Aiming errors, but therapy techniques, such as visual scanning training, do not take this into account. Here, we evaluated (1) whether instructing neglect patients to move midline body parts improves their ability to explore left space and (2) whether this has a different impact on different patients. A 68-year-old woman with spatial neglect after a right basal ganglia infarct had difficulty orienting to and identifying left-sided objects. She was prompted with four instructions: “look to the left,” “point with your nose to the left,” “point with your [right] hand to the left,” and “stick out your tongue and point it to the left.” She oriented leftward dramatically better when pointing with the tongue/nose, than she did when pointing with the hand. We then tested nine more consecutive patients with spatial neglect using the same instructions. Only four of them made any orienting errors. Only one patient made >50% errors when pointing with the hand, and she did not benefit from pointing with the tongue/nose. We observed that pointing with the tongue could facilitate left-sided orientation in a stroke survivor with spatial neglect. If midline structures are represented more bilaterally, they may be less affected by Aiming bias. Alternatively, moving the body midline may be more permissive for leftward orienting than moving right body parts. We were not able to replicate this effect in another patient; we suspect that the magnitude of this effect may depend upon the degree to which patients have directional akinesia, spatial Where deficits, or cerebellar/frontal cortical lesions. Future research could examine these hypotheses.

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Disorders of vision and visual-perceptual dysfunction

Cited by 7 publications

References 50 publications

Comprehensive Evaluation of Healthy Volunteers Using Multi-Modality Brain Injury Assessments: An Exploratory, Observational Study

Comprehensive Evaluation of Healthy Volunteers Using Multi-Modality Brain Injury Assessments: An Exploratory, Observational Study

A Cross-sectional Survey and Cross-sectional Clinical Trial to Determine the Prevalence and Management of Eye Movement Disorders and Vestibular Dysfunction in Post-Stroke Patients in the Sub-Acute Phase: Protocol

Midline Body Actions and Leftward Spatial “Aiming” in Patients with Spatial Neglect

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