7.20 Differences in Pupillary Light Reflex Metrics after Concussion Persist at Clinical Objective

Objective Pupillary light reflex (PLR) metrics are enhanced in adolescents with concussion. It is not known if these PLR metrics in concussed adolescents return back to the normal range at recovery. Our objective in this study is determine the potential utility of PLR metrics as physiological biomarker for concussion recovery. Design Prospective cohort study. Setting Specialty concussion program. Participants Adolescents, ages 12 and 19 years. Interventions (or Assessment of Risk Factors) Clinical concussion evaluation and PLR assessment using pupillometry. Outcome Measures Clinical concussion recovery, PLR metrics (maximum/minimum pupil diameter, percentage constriction, latency, average/peak constriction/dilation velocity, T75 [time to 75% re-dilation]). Main Results 6 of 9 PLR metrics continued to be significantly enhanced among concussed cases after Bonferroni correction (minimum pupil diameter: 2.96 mm vs 2.66 mm; difference, 0.31; 99.4% CI, 0.17–0.44; percentage constriction: 37.84% vs 32.91%; difference, 4.93; 99.4% CI, 2.98–6.88; average constriction velocity: 3.09 mm/s vs 2.50 mm/s; difference, 0.59; 99.4% CI, 0.38–0.79; average dilation velocity, 1.34 mm/s vs 1.24 mm/s; difference, 0.11; 99.4% CI, 0.01–0.20; peak dilation velocity: 1.86 mm/s vs 1.66 mm/s; difference, 0.20; 99.4% CI, 0.08–0.31; and T75: 1.73 seconds vs 1.46 seconds; difference, 0.27; 0.10–0.44) compared to healthy adolescents. Conclusions Enhancement of PLR metrics in concussed adolescents may persist after clinical recovery and may have implications for return to risk activities such as contact or collision sports.