Visual Evoked Potential Response Among Drug Abusers- A Cross Sectional Study.

INTRODUCTION: There is important preclinical evidence that substance abuse may produce neurophysiological disturbances particularly in relation to altered neural synchronization in Visual Evoked Potentials (VEP).

AIM: The purpose of current study was to compare the latencies and amplitudes of different waveforms of VEP among different drug abusers and controls and also to identify early neurological damage so that proper counseling and timely intervention can be undertaken.

MATERIALS AND METHODS: VEP was assessed by Data Acquisition and Analysis system in a sample of 58 drug abusers, all males, within age group of 15-45 years as well as in age matched 30 healthy controls. The peak latencies and peak to peak amplitudes of different waveforms were measured by applying one-way Anova test and unpaired t-test using SPSS version 16.

RESULTS: In between drug abusers and controls, the difference in the duration of N75 and P100 waveform of VEP was found to be statistically highly significant (p<0.001) in both the eyes. Also the amplitude of wave P100 was found to be decreased among drug abusers in both eyes.

CONCLUSION: Chronic intoxication by different drugs has been extensively associated with amplitude reduction of P100 and prolonged latency of N75 and P100 reflecting an adverse effects of drug dependence on neural transmission within primary visual areas of brain.