Effect of binasal occlusion (BNO) and base-in prisms on the visual-evoked potential (VEP) in mild traumatic brain injury (mTBI)

Clinical characteristics of visual motion hypersensitivity: a systematic review

This qualitative systematic review presents an overview of the state of the research relating to visual motion hypersensitivity (VMH) and offers a reference tool for future studies in the field. The study set out to identify and collate articles investigating risk groups with aberrant responses to visual motion as compared to healthy control groups, presenting evidence for risk factors associated with visual motion hypersensitivity. Data were synthesized into the state of the research and analyzed in the context of the clinical characteristics of each risk factor. Literature searches were performed on Medline Ovid, EMBASE, Web of Science, and Cinahl, identifying a total of 586 studies of which 54 were finally included. Original articles published between the dates of commencement for each database and 19th January 2021 were included. JBI critical appraisal tools were implemented for each corresponding article type. In total, the following number of studies was identified for each respective risk factor: age (n = 6), migraines (n = 8), concussions (n = 8), vestibular disorders (n = 13), psychiatric conditions (n = 5), and Parkinson's disease (n = 5). Several studies described VMH as the primary concern (n = 6), though these primarily included patients with vestibulopathies. There were considerable differences in the nomenclature employed to describe VMH, depending largely on the investigating group. An overview of investigated risk factors and their evaluation methods was presented in a Sankey diagram. Posturography was the most implemented methodology but due to diverse measurements meta-analyses were not possible. One may however note that while the easily implemented Vestibular Ocular Motor Screening (VOMS) was designed for concussed patients, it may prove useful for other risk groups.

Sensory sensitivity after acquired brain injury: A systematic review

Patients with acquired brain injury frequently report experiencing sensory stimuli as abnormally under- (sensory hyposensitivity) or overwhelming (sensory hypersensitivity). Although they can negatively impact daily functioning, these symptoms are poorly understood. To provide an overview of the current evidence on atypical sensory sensitivity after acquired brain injury, we conducted a systematic literature review. The primary aim of the review was to investigate the behavioural and neural mechanisms that are associated with self-reported sensory sensitivity. Studies were included when they studied sensory sensitivity in acquired brain injury populations, and excluded when they were not written in English, consisted of non-empirical research, did not study human subjects, studied pain, related sensory sensitivity to peripheral injury or studied patients with a neurodegenerative disorder, meningitis, encephalitis or a brain tumour. The Web of Science, PubMed and Scopus databases were searched for appropriate studies. A qualitative synthesis of the results of the 81 studies that were included suggests that abnormal sensory thresholds and a reduced information processing speed are candidate behavioural mechanisms of atypical subjective sensory sensitivity after acquired brain injury. Furthermore, there was evidence for an association between subjective sensory sensitivity and structural grey or white matter abnormalities, and to functional abnormalities in sensory cortices. However, further research is needed to explore the causation of atypical sensory sensitivity. In addition, there is a need for the development of adequate diagnostic tools. This can significantly advance the quantity and quality of research on the prevalence, aetiology, prognosis and treatment of these symptoms.

Binasal Occlusion Intervention to Support Occupational Performance for People With Traumatic Brain Injury With Visual Symptoms (June 2013-October 2020)

Systematic Review Briefs provide a summary of the findings from systematic reviews developed in conjunction with the American Occupational Therapy Association's Evidence-Based Practice Program. Each Systematic Review Brief summarizes the evidence on a theme related to a systematic review topic. This Systematic Review Brief presents findings from the systematic review on the effectiveness of binasal occlusion interventions that address visual impairments and visual perception to improve occupational performance for adults with traumatic brain injury.

Mild-to-Moderate Traumatic Brain Injury: A Review with Focus on the Visual System

Traumatic Brain Injury (TBI) is a major global public health problem. Neurological damage from TBI may be mild, moderate, or severe and occurs both immediately at the time of impact (primary injury) and continues to evolve afterwards (secondary injury). In mild (m)TBI, common symptoms are headaches, dizziness and fatigue. Visual impairment is especially prevalent. Insomnia, attentional deficits and memory problems often occur. Neuroimaging methods for the management of TBI include computed tomography and magnetic resonance imaging. The location and the extent of injuries determine the motor and/or sensory deficits that result. Parietal lobe damage can lead to deficits in sensorimotor function, memory, and attention span. The processing of visual information may be disrupted, with consequences such as poor hand-eye coordination and balance. TBI may cause lesions in the occipital or parietal lobe that leave the TBI patient with incomplete homonymous hemianopia. Overall, TBI can interfere with everyday life by compromising the ability to work, sleep, drive, read, communicate and perform numerous activities previously taken for granted. Treatment and rehabilitation options available to TBI sufferers are inadequate and there is a pressing need for new ways to help these patients to optimize their functioning and maintain productivity and participation in life activities, family and community.

Rehabilitation of visual disorders

While there is a long history of rehabilitation for motor deficits following cerebral lesions, less is known about our ability to improve visual deficits. Vision therapy, prisms, occluders, and filters have been advocated for patients with mild traumatic brain injury, on the premise that some of their symptoms may reflect abnormal visual or ocular motor function, but the evidence for their efficacy is modest. For hemianopia, attempts to restore vision have had unimpressive results, though it appears possible to generate blindsight through training. Strategic approaches that train more efficient use of visual search in hemianopia have shown consistent benefit in visual function, while prism aids may help some patients. There are many varieties of alexia. Strategic adaptation of saccades can improve hemianopic alexia, but there has been less work and mixed results for pure alexia, neglect dyslexia, attentional dyslexia, and the central dyslexias. A number of approaches have been tried in prosopagnosia, with recent studies of small groups suggesting that face perception of prosopagnosic subjects can be enhanced through perceptual learning.

Vision therapy: Occlusion, prisms, filters, and vestibular exercises for mild traumatic brain injury

A number of treatment approaches have been advocated for persistent visual complaints following mild traumatic brain injury. These include devices such as binasal occlusion, yoked prisms, vertical prisms, and filters, as well as vestibular training. We discuss the rationale and the evidence for each of these approaches. Binasal occlusion has been advocated for visual motion sensitivity, but it is not clear why this should help, and there is no good evidence for its symptomatic efficacy. Base-in prisms can help manage convergence insufficiency, but there are few data on their efficacy. Midline shift is an unproven concept, and while the yoked prisms advocated for its treatment may have some effect on egocentric neglect, their use in mild traumatic brain injury is more questionable. A wide variety of posttraumatic symptoms have been attributed to vertical heterophoria, but this is an unproven concept and there are no controlled data on the use of vertical prisms for mild traumatic brain injury symptoms. Filters could plausibly ameliorate light intolerance but studies are lacking. Better evidence is emerging for the effects of vestibular therapy, with a few randomized controlled trials that included blinded assessments and appropriate statistical analyses. Without more substantial evidence, the use of many of these techniques cannot be recommended and should be regarded as unproven and in some cases implausible.

Frontal theta-gamma ratio is a sensitive index of concussion history in athletes on tasks of visuo-motor control

Patients with mTBI often show deficits in executive function and changes in neural activity. Similar changes in those with a history of mTBI (i.e. concussion), however, have not been consistently reported. Frontal theta-to-gamma frequency ratio has shown promise in EEG research in predicting performance on working memory tasks. In the present study we explored the sensitivity of the frontal theta-to-gamma relative power spectral density (PSD) ratio to the history of concussion in 81 youth athletes (18 with a history of concussion, ages 13–18) during the tests of the Nike Sensory Training Station that vary in working memory and processing speed demands and motor output requirements. The results showed that the theta-to-gamma relative PSD ratio was significantly lower in the concussion history group on the tests of target capture, perception span and hand reaction time. A principle component analysis further indicated that this metric reflects an underlying dimension shared by several visuo-motor control tests of the Nike battery. The results suggested persistent deficits in psychomotor ability in the athletes with a history of concussion that may have implications for diagnosis, rehabilitation and athletic training.

Visual problems associated with traumatic brain injury

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 describes: (1) the major clinical and pathological features of TBI; (2) the visual signs and symptoms associated with the disorder; and (3) discusses the assessment of quality of life and visual rehabilitation of the patient. Defects in primary vision such as visual acuity and visual fields, eye movement including vergence, saccadic and smooth pursuit movements, and in more complex aspects of vision involving visual perception, motion vision ('akinopsia'), and visuo-spatial function have all been reported in TBI. Eye movement dysfunction may be an early sign of TBI. Hence, TBI can result in a variety of visual problems, many patients exhibiting multiple visual defects in combination with a decline in overall health. Patients with chronic dysfunction following TBI may require occupational, vestibular, cognitive and other forms of physical therapy. Such patients may also benefit from visual rehabilitation, including reading-related oculomotor training and the prescribing of spectacles with a variety of tints and prism combinations.

Binasal Occlusion (BNO), Visual Motion Sensitivity (VMS), and the Visually-Evoked Potential (VEP) in mild Traumatic Brain Injury and Traumatic Brain Injury (mTBI/TBI)

The diagnosis and treatment of the possible visual sequelae in those with traumatic brain injury (TBI) represents an important area of health care in this special population. One of their most prevalent yet elusive visual symptoms is visual motion sensitivity (VMS). In this review, we present the basic VMS phenomenon and its related symptoms, clinical studies in the area, clinical research investigations using the visual-evoked potential (VEP) as a cortical probe, and possible mechanisms and related neurophysiology that may underlie VMS. Lastly, therapeutic interventions are briefly described, as well as future directions for clinical research and patient care in those with VMS and TBI.