Unilateral diaphragmatic paralysis: an electrophysiological study.

An electrophysiological study was carried out on four patients with unilateral diaphragmatic paralysis. Whereas neurogenic involvement of the paralysed hemidiaphragm was roughly similar in all cases, neurogenic patterns could be detected in the normally moving contralateral hemidiaphragm in three cases, and the degree of involvement could be correlated with the respiratory state of the patients. EMG also showed that the neuropathic process affected the limb muscles. Thus unilateral diaphragmatic paralysis may be, at least in some cases, the localised expression of a more diffuse neuropathy, perhaps a peculiar form of neuralgic amyotrophy.