Electrophysiological evaluation of central and peripheral neural effects of lead exposure

Lead encephalopathy is more usual in children and has rarely been observed in adults. Peripheral neuropathy on the other hand is of more common occurrence among adults with occupational lead exposure, and has been extensively studied with electrophysiological methods. Although encephalopathy often manifests itself with generalized seizures, usual electroencephalographic (EEG) findings have been diffuse slow wave abnormalities. Paroxysmal abnormalities either focal or generalized spikes and/or sharp waves have been detected in some patients. Evoked potential studies have lately been applied to children or adults with a relatively low level of lead exposure, and minor dose-dependent differences have appeared in comparison to control groups. Subclinical signs of peripheral neuropathy have been detected among human subjects with various levels of lead exposure. Nerve conduction velocities of lead workers have been generally lower, although the means have been within normal limits. Some authors have shown clear correlations between measures of lead exposure and nerve conduction velocities indicating an exposure--effect relationship.