Pre- to Postseason Reliability of Blink Reflex Parameters in Nonconcussed Athletes.

Abstract

Objective: To evaluate the reliability of blink reflex parameters across a sports season in nonconcussed high school athletes.

Design: Prospective cohort study.

Setting: High school athletics programs in a tertiary research context.

Participants: Thirty-two nonconcussed high school athletes [17 (53.1%) females; mean age 15.3 (SD = 1.1) years] completed pre- and postseason blink reflex testing using the EyeStat blink reflexometer.

Independent variables: Demographic, sport, and concussion histories were obtained for all athletes. The primary independent variable was sport type (contact vs limited contact).

Main outcome measures: Ten blink parameters were analyzed: latency, differential latency, delta 30, time under threshold, oscillations, total blink time, lid excursion, lid velocity, time to close, and time to open. Pre- to postseason changes were evaluated using Wilcoxon signed-rank tests. Reliability was assessed through intraclass correlation coefficients (ICC) and Spearman correlations. Linear regression models, adjusting for age, sex, and concussion history, examined the effect of sport type on parameter changes.

Results: Three blink parameters-delta 30 (P = 0.015), time under threshold (P = 0.003), and oscillations (P < 0.001)-showed significant pre-/postseason changes, while the remaining 7 remained stable. Absolute-agreement ICCs indicated poor reliability for latency (ICC = 0.488) and differential latency (ICC = 0.390) and moderate reliability for the remaining parameters (ICC = 0.631-0.724). No measures differed between contact and limited-contact sports.

Conclusions: Most blink parameters were stable across a season in nonconcussed athletes, but reliability was parameter dependent (poor for latency and differential latency; moderate for others). Sport type was not associated with preseason-to-postseason changes. These findings support blink reflexometry as a feasible objective adjunct for longitudinal assessment in concussion research, while highlighting the need to account for seasonal drift and parameter-specific reliability.