Visual Evoked Potential and Voltage Changes Associated with Acute Concussion and Frequency Specific Photophobia

Abstract

ObjectiveIn this paper we present a case series of concussion patients' VEP as well as a single concussion patient with a VEP baseline and post concussion VEP data.BackgroundVisual Evoked Potentials (VEP) are a means of measuring the electrical behavior of the brain following a visual stimuli. The use of VEP for diagnostics following traumatic brain injury (TBI) is emerging with additional data concerning sports related concussion coming.Design/MethodsDuring the 2016 spring football season there was 1 concussion of a subject who had a VEP baseline and a VEP performed during the acute phase of the concussion. Concurrently we have been using VEP for concussion patients who have not had a baseline. Fifteen subjects in the post acute phase; while symptomatic, had VEP performed using White, Red, Blue and Green for the evoked potentials.ResultsThe patient with a VEP baseline had increased voltages with subtle slowing of N75 and P100. N75 increased from 67.5 msec at baseline to 75.1 msec post concussion. Voltages went from 19.3 mVolts to 24.6 mVolts post concussion. Also, the colored flashes associated with the lowest voltages were consistent with mitigation of frequency specific photophobia; 20.9 mVolts for mitigation color compared (red) to 24.6 for white. In the concussion population studied (N = 15) the voltages where the color corresponded to symptom relief were: 10.9 ± 5.7 mVolts compared to symptom evoking voltages 12.7 ± 6.3 (p = 0.0031) mVolts.ConclusionsIn this paper we present evidence of VEP changes in one acute concussion patient as well as a population of concussion patients where voltages are increased post concussion. The increased voltages associated with color VEP may be a useful technique to assess frequency specific photophobia as well as helping manage post concussion photophobia. Futures studies to assess the utility of VEP as a concussion management tool are needed.