[Neurophysiologic study of the phrenic nerve]

Phrenic nerve conduction was studied in 19 volunteers using two different percutaneous methods of stimulation, mono and bipolar. A response was obtained in all nerves studied. The results are comparable using mono or bipolar stimulation method. No significant difference in latency, amplitude, or intensity stimulation applied was found between left and right sides. There was no correlation of age or height with the latency. Latencies above 10 ms or differences between right and left above 1.6 ms are abnormal values. We studied two patients with neurological disorders, one of them with Guillain-Barré syndrome and the other with a bulbar form of Amyotrophic Lateral Sclerosis and respiratory failure. Both of them had prolonged conduction time. This method permits reliable analysis of localized phrenic lesions and abnormalities induced in either the phrenic nerveor diaphragm by generalized disease processes.