Visual evoked potentials in primary hypertension.

Functional integrity of sensory pathways in the brain has not been well documented in hypertension. It is suggested that vascular endothelial changes including hyalinisation during hypertension may lead to demyelination in the vulnerable areas of the brain. Since optic nerve is considered to be part of brain hence the present study was done to find out if visual pathways are involved in hypertension. Transient pattern reversal visual evoked potentials (VEPs) from 01, 02 scalp regions were recorded in 23 primary hypertensive patients and compared with 14 normotensive control. Of these, six patients showed delayed P1 latencies beyond 99% tolerance limit i.e. Mean + 3 SD of normal. The remaining 17 had latencies of all positive (P1-P3) and negative (N1-N3) waves comparable to those of the control group. Correlation Coefficient worked out, showed significant correlation between systolic BP and P1 latency in the control group only. No other parameter showed any correlation with P1 latency & amplitude in both the groups. These findings show that fluctuations of BP in normotensive subjects have correlation with P1 latency. This correlation ceased to exist in hypertensive patients and abnormality in P1 latency of VEP was detected in 26% cases.