Ocular motor disorders in children and adults with mTBI: a scoping review protocol.

INTRODUCTION: Ocular motor function is susceptible to neurological injury because it requires a large portion of brain circuitry including every lobe of the brain, brainstem, thalamus, basal ganglia, cerebellum, cranial nerves and visual tracts. While reports of a high frequency of ocular motor dysfunctions after mild traumatic brain injury (mTBI) span multidisciplinary journals, there is no scoping review of the signs, diagnostic assessments and criteria, and appropriate management of ocular motor disorders post-mTBI. Post-mTBI ocular motor dysfunction has been reported to respond to active treatment. The objective of this scoping review is to map the available evidence on the diagnostic assessment and treatment modalities currently used in the management of mTBI-related ocular motor disorders in children and adults. This scoping review also aims to identify gaps in the current literature and provide suggestions for future research. METHODS AND ANALYSIS: This review will include populations with reported concussion and/or mTBI without restrictions on age, race, sex or time since injury. The review will evaluate the reported symptoms related to ocular motor dysfunction, types of assessments and diagnostic criteria used, reported treatments, and the level of evidence supporting the reported treatments. This review will exclude literature on brain injury of non-traumatic aetiology and moderate/severe traumatic brain injury. Ocular motor dysfunction after mTBI appears in journals across multiple disciplines. Thus, multiple databases will be evaluated including Pubmed, Embase, PEDro, OVID, Clinical Key, Google Scholar and REHABDATA. Literature will be searched from inception to present day. Evidence sources will include experimental study designs including randomised controlled trials, non-randomised controlled trials and interrupted time-series. Additionally, analytical observational studies including prospective and retrospective cohort studies, case series, cross-sectional studies and clinical practice guidelines will be considered for inclusion. Data will be extracted on clinical presentation, frequency, assessment, diagnostic criteria management strategies and outcomes of concussion and mTBI-related ocular motor disorders. ETHICS AND DISSEMINATION: This scoping review will use data from existing publications and does not require ethical approval by an institutional review board. Results will be disseminated through publication in a peer-reviewed scientific journal and presented at relevant conferences and as part of future workshops with professionals involved with diagnosis and management of patients with mTBI.

Case Series: Periodic Accommodative Fluctuations after Concussion.

SIGNIFICANCE: This is the first report recording an accommodative disorder after concussion characterized by periodic moderately sized myopic refractive error fluctuations without measurable other features of spasm of the near reflex. PURPOSE: Objectively document a class of accommodative dysfunction that may be related to concussion. CASE REPORTS: Case 1 involved two sports-related concussions 2 months apart with symptoms of headache and variable blur. Refractive stability was measured 28 months after injury with a binocular open-field refractometer documenting fluctuations from -0.25 to -1.75 D occurring 10 times during 4.2 seconds of recording with no evident miosis or convergent strabismus. The symptoms resolved with 1% atropine × 3 weeks. Case 2 involved a concussive blast injury (improvised explosive device) 7 years prior with symptoms of headache behind the eyes and occasional variable blur and reduced tolerance of electronic displays and other visually intensive tasks. Refractive fluctuations from +0.50 to -2.00 D occurred seven times over 44 seconds of recording with no appreciable miosis or change of interpalpebral fissure. The signs and symptoms were unresponsive to seven occupational therapy sessions involving task modifications and accommodative vision therapy activities. CONCLUSIONS: In patients complaining of blurry vision, a careful evaluation of the stability of accommodation is indicated.

Vergence Endurance Test: A Pilot Study for a Concussion Biomarker.

The Vergence Endurance Test (VET), a quantitative and objective eye movement assessment, was utilized to differentiate control from concussed subjects. Nine symptomatic concussed (2 male; 30.8 ± 11 years) and 9 asymptomatic control (6 male; 25.1 ± 1.4 years) subjects participated in the VET. Symmetrical disparity vergence step targets were presented with and without visual distractors. A masked data analyst measured vergence latency, peak velocity, response amplitude, settling time, and the percentage of trials which contained blinks. A Binocular Precision Index (BPI) and a Binocular Accuracy Index (BAI) were calculated to quantify the changes that occur in the vergence parameters over the duration of the VET. Convergence and divergence peak velocity, divergence response amplitude, the percentage of trials that contained blinks during the transient portion of the response, and the BAI were significantly (p < 0.05) different between the concussed and the control subjects. For these parameters, the BAI and divergence response amplitude yielded the greatest accuracy, 78%, in their ability to discriminate between the groups. The VET objectively measures the change in vergence performance over time and shows promise as a method to diagnose a concussion. Future studies will determine whether the VET can be used to assess the extent of natural recovery and the effectiveness of therapeutic interventions.