[Tomaculous neuropathy. Electrophysiologic study].

In two cases with recurrent palsies, the results of electrophysiological studies led to nerve biopsy showing typical tomacula. The first case was an inherited neuropathy with liability to pressure palsies. The second case was an apparently sporadic painless recurrent brachial neuropathy. Electrophysiological alterations were diffuse and sensory fibres of the median nerve between index and wrist were the most involved. Conduction blocks were observed without palsy in narrow anatomical passageways where nerve compressions are frequent (ulnar nerve at the elbow, peroneal nerve at the fibula). A compression by a neighbouring anatomical structure could make the prognosis worse and justify nerve decompression. The nerves with slowest conduction have the most important risk of palsy and the patients should be given advice to avoid their compression.