Chronic multifocal demyelinating neuropathy simulating motor neuron disease.

We describe a patient with a chronic acquired predominantly motor polyneuropathy. His clinical picture initially led to a diagnosis of lower motor neuron form of amyotrophic lateral sclerosis. However electrophysiological examination revealed multifocal, prevalently proximal, conduction blocks at sites not prone to compression. Distinguishing this unusual polyneuropathy from motor neuron diseases is critical, since the former is a potentially, treatable disorder.