Peripheral neuropathy in epileptic patients.

The prevalence of peripheral neuropathy in 186 epileptic patients was 16.7%. The neuropathy was characterized by stocking hypesthesia and reduced Achilles reflexes, and it occurred with all anticonvulsant agents. Electrophysiologic tests indicated slowing of peroneal and sural nerve conduction velocity and prolongation or absence of H reflexes and F responses. The prevalence of neuropathy was not greater in patients receiving phenytoin, and there was no relationship between clinical or electrical abnormalities and blood levels or duration of treatment for either phenytoin or phenobarbital. We did not find a specific relationship between phenytoin usage and peripheral neuropathy in epileptic patients.

Toward more rational nerve conduction interpretations: the effect of height.

One hundred four normal subjects ranging in age from 17 to 77 years and in height from 115 to 203 cm underwent nerve conduction studies of sural, peroneal, tibial, and median nerves. Foot temperature was measured in each patient. A strong inverse correlation was found between height and sural (r = -0.7104), peroneal (r = -0.6842), and tibial (r = -0.5044) conduction velocities. These correlations were significant at the P less than 0.001 level. Median conduction velocity was not correlated with height. Height was correlated with the distal latencies of all nerves studied (sural r = 0.6518, peroneal r = 0.4583, tibial r = 0.7217, median r = 0.5440). These correlations were significant at the P less than 0.001 level. Age was inversely correlated with both tibial (r = -0.4071) and median (r = -0.3464) nerve conduction velocities but not with sural and peroneal conductions. There were no correlations between distal latencies and age. If the variation in conduction velocity accounted for by the linear relationship with height was removed, then age would be inversely correlated to all conduction velocity measurements with the exception of the sural. Temperature is inversely correlated with the sural (r = -0.2233), peroneal (r = -0.2102), and tibial (r = -0.2710) distal latencies. In all instances, the effects of age and temperature were minor determinants when compared with the effects of height. Diagnostic conclusions made from nerve conduction data without correcting for height may be invalid in patients taller and shorter than normal.(ABSTRACT TRUNCATED AT 250 WORDS)