ELECTROPHYSIOLOGICAL FINDINGS IN PERIPHERAL FIBERS OF SUBJECTS WITH AND WITHOUT POSTHERPETIC NEURALGIA

The peripheral nervous system was studied using classical electrophysi ological methods in 23 subjects with post-herpetic neuralgia (PHN), an d compared with the same parameters in 64 herpes tester (HZ) patients without PHN. The findings indicated sensory axonopathy, the severity o f which varied in different patients. Ten percent of all cases showed segmental paresis corresponding to dermatomes affected by HZ. In anoth er 17% of patients axonal motor damage was only detectable by EMG as d enervation. No statistically significant difference was found between the two groups in the mean percentage differences of the electrophysio logical data for peripheral sensory fibres with respect to mean contro l values, or between sides affected by HZ and healthy sides. Hence HZ is associated with sensory axonopathy, the severity of which is simila r, on the whole, in the groups with and without PHN and stable in time . This suggests that damage to peripheral large-diameter sensory fibre s is not the cause of PHN.