Standard neurologic examinations may not detect abnormalities in U.S. military service members with persistent post-concussive symptoms following mild traumatic brain injury. The Brain Injury and Mechanisms of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury Study (BIMA) enrolled 71 participants September 2012-May 2014. Participants received: comprehensive neurological and oculomotor exam; balance testing (Berg Balance Scale-BBS; Romberg Test-RT, Sharpened Romberg Test-SRT); olfactory function (Brief Smell Identification Test-BSIT). Two trained neurologists conducted the examinations at a central facility in Colorado Springs. Median age was 32 years (range 21-53), 99% male, 82% Caucasian, 49% PTSD, 28% most recent qualifying injury three months to one year prior to enrollment, 32% blast injuries only, and 73% multiple injuries. Some participants presented with abnormal facial sensation (15%), abnormal tandem gait (13%), and tremor (11%). 54% had abnormal near point of convergence (abnormal range 13-80 cm). 86% scored ≥ 55 on the BBS, with no participant scoring ⟨ 50. 49% scored ⟨ 30 seconds on the best trial of the SRT. RT was abnormal in 10%. 15% of participants scored ≤ 9 (out of 12) on BSIT, about twice what is expected in a normal population. The neurological examination found abnormalities across a range of testing, with convergence insufficiency and SRT having the most sensitivity.
Trial registration: ClinicalTrials.gov Identifier: NCT01611194; https://clinicaltrials.gov/show/NCT01611194.
Keywords: brain concussion; neurological examination; post-concussive syndrome.
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