Combining Visual Target Tracking and Time Estimation to Assess Vestibular and Oculomotor Function after Concussion: 2267 Board #7 June 2, 3: 15 PM - 5: 15 PM.

Concussions affect an estimated 1.6 to 3.8 million people in the United States annually. Dizziness, which may manifest as a result of vestibular or oculomotor impairments, is a common symptom (>50%) following concussion and is associated with increased risk for protracted recovery. PURPOSE:To evaluate a novel measure of vestibular and oculomotor function after sub-acute concussion in an immersive testing environment. METHODS: 26 participants (age: 17.6 ± 4.8 years) presenting with dizziness or imbalance after concussion (32.9 ± 37.2 days post injury, range: 1-156 days) and 100 controls (age: 17.03 ± 3.8 years) were tested in this study. Participants visually tracked a target moving on a 180° arc trajectory toward an optical goal in an immersive visual environment. 10 trials of four conditions were performed including combinations of target speed and visibility (slow-visible, fast-visible, slow-invisible, fast-invisible). During the invisible condition the target disappeared after 60° of arc and the participant predicted when the target would arrive at the optical goal. The angle difference, or error, between the stopped target and the goal was recorded for each trial. A one-way ANOVA was performed for each condition to compare the concussed and control groups. RESULTS: Concussed participants demonstrated increased mean error during the visible-fast (concussed: 5.9 ± 3.9, controls: 4.5 ± 3.7; p<0.01) and invisible-fast (concussed: 16.6 ± 9.8, controls: 14.3 ± 10.3; p<0.05) conditions compared to controls. There were no detectable performance differences tracking slow targets. CONCLUSION: The combination of fast visual target tracking and time estimation may be a suitable measure to assess vestibular and oculomotor dysfunction following concussion. The current findings support the inclusion of vestibular and oculomotor testing presented in a virtual reality or immersive technology format in the assessment of concussion. This project was supported by the Head Health Challenge II (sponsored by Under Armour, Inc, the National Football League, and General Electric Institution) and the US Army Medical Research Acquisition Activity #W81XWH-12-C-0203