Needle electromyography of the diaphragm.

A method is described for performing needle electromyography of the diaphragm which is safe and causes little discomfort. It provides valuable information concerning neuropathies and myopathies which may affect the diaphragm, and complements information derived from phrenic nerve conduction studies. Firing patterns of motor unit potentials during spontaneous respiration identify upper motor neurone disorders causing respiratory insufficiency.