Temporal visual processing deficits in post concussion syndrome

Post-concussive (PCS) motion hypersensitivity represents a common sequela of mild traumatic brain injury. This study investigated whether PCS alters visual temporal resolution thresholds in psychophysical measures that sustain motion detection. Fifteen PCS patients and fifteen age-matched controls underwent critical flicker fusion (CFF) threshold assessments across visual-field eccentricities. A Generalized linear mixed model tested group differences in CFF thresholds, treating eccentricity as a repeated factor and including CFF variability as a covariate. Pupil measurements and catch trials controlled for fatigue and alertness. Nonparametric correlations assessed relationships among time from injury, symptom severity, and CFF measures. Results showed CFF variability heightening CFF thresholds in the PCS group to a significantly larger extent compared to controls. Absence of significant CFF variability differences between groups, and modulation by eccentricity, suggests perceptual noise more strongly influences the overall visual temporal sensitivity in PCS. Days since injury negatively correlated with variability, indicating compensatory stabilization of temporal sensitivity over time. Symptom severity did not correlate with CFF measures. In conclusion, PCS motion hypersensitivity may reflect disturbances in visual temporal processing parameters, potentially involving altered internal neural noise. Although some recalibration occurs post-injury, persistent abnormalities underscore the need for further research into early, clinical interventions targeting perceptual noise.