Comparison of visual evoked potential variability in eyes affected by optic neuritis and fellow eyes.

Abstract

Purpose: This study compared the variability of visual evoked potential (VEP) in response to stimulation of eyes affected by unilateral optic neuritis with that of fellow (non-affected) eyes.

Methods: Pattern-reversal VEP (PVEP) and motion-onset VEP (MVEP) recordings from thirty-six subjects with unilateral optic neuritis at different intervals from disease onset were retrospectively evaluated, and differences in the following parameters were compared: signal‒to‒noise ratio (SRN), interquartile range of the response jitter (jitter IQR), and number of trials corresponding to the average response (corresponding N).

Results: In the PVEP recordings, the P1 peak times of the fellow eyes were significantly shorter than those of the affected eyes (Cohen's d = -1.470, p < 0.001). P1 amplitudes were significantly greater in fellow eyes (d = 1.17, p < 0.001). Significant differences were found in the SNR (d = 0.782, p < 0.001), jitter IQR (d = -0.874, p < 0.001), and corresponding N (d = 0.700, p < 0.001). MVEP presented significantly shorter N2 peak times in fellow eyes than in affected eyes (d = 0.840, p < 0.01) and significantly greater amplitudes (d = 0.494, p = 0.002). There was a significant difference in the SNRs (d = 0.440, p = 0.01) and corresponding N values (d = 0.415, p = 0.01). There was no difference in the jitter IQR (d = 0.143, p = 0.230).

Conclusions: The increased variability in eyes affected by optic neuritis compared with fellow eyes (in particular, in pattern-reversal VEP, which predominantly represents the activity of the macular-papillary fibers of the optic nerves) may represent important pathophysiologic features and may add valuable information to diagnostics via VEP examinations.