Peripheral and central conduction in n-hexane polyneuropathy.

Electrophysiological findings of 27 males with industrial n-hexane polyneuropathy (HPNP) are presented. The results of needle electromyography and nerve conduction studies were compatible with primarily axonal polyneuropathy with secondary segmental demyelination. Motor conduction velocities were the slowest in distal regions of the nerves. In the proximal nerve segments, which were partly tested by magnetic stimulation of the nerve roots, this slowing was much less pronounced. The reduction in mean motor conduction velocities in the forearm segments of ulnar nerves was more than 30% in comparison to the control group means. This reduction was only 10% in the neck-axilla segments. We think that this finding is a reflection of the distal axonopathy process. Central motor conduction times calculated by transcranial magnetic stimulation and spinal nerve root stimulation were found to be prolonged in HPNP patients, indicating that descending motor pathways are affected in human HPNP.