Association of Height With Pattern Reversal Visual Evoked Potentials.

Abstract

This study was conducted to investigate whether pattern reversal visual evoked potential parameters in a large sample of healthy subjects are influenced by height of the subjects. It was an institutional, cross-sectional study. Pattern reversal visual evoked potential (PRVEP) recordings from 400 eyes from 200 normal subjects were performed in the Neurophysiology unit of the Department of Physiology in accordance to the standardized methodology and montages were kept as per 10-20 International System of electroencephalogram electrode placements. VEP latencies, duration and amplitude were measured in all subjects. The correlation of all the electrophysiological parameters with height was evaluated by Pearson's correlation co-efficient (r) and its statistical significance was evaluated. On correlating mean height with mean VEP parameters of both eyes in the subjects it was found that there is a positive correlation of P100 latency and N155 latency in the subjects and a highly significant negative correlation of P100 amplitude with height in the subjects of various age groups. N70 latency was found to be significantly positively correlated with height whereas P100 Duration showed a non-significant negative correlation with height of the subjects. Our findings suggest that VEP latencies, duration and amplitude are influenced by the height of the individual. The positive correlation between VEP latencies and increasing height may all reflect the increase in length between the optic nerve head and the visual processing areas-the striate and the extra striate cortex which are the main generators of the various PRVEP waveforms.