Long-term effects of methamphetamine abuse on visual evoked potentials.

Abstract

To compare visual evoked potential (VEP) components in normal individuals and those with long-term methamphetamine and crystal methamphetamine use. In this study, monocular pattern-reversal VEPs were recorded in 40 methamphetamine and crystal methamphetamine users and 38 normal individuals. Visual stimuli were high-contrast (99%) checkerboard patterns at 15 and 60 min of arc with a reversal rate of 1.53 reversals per second. A significant difference was seen between the two groups for the P100 peak time for the 60 min of arc checks (p= 0.002, d= 0.75, 4.61% higher peak time in the addicted group) and the 15 min of arc checks (p= 0.004, d= 0.73, 4.78% higher peak time in the addicted group). However, other VEP components were not significantly different between the two groups. The higher P100 peak time at both 15 and 60 min of arc in methamphetamine-dependent users reveals that VEPs are highly sensitive for the diagnosis of retinal and visual pathway lesions.