PHRENIC-NERVE CONDUCTION IN AMYOTROPHIC-LATERAL-SCLEROSIS

Respiratory failure accounts for the majority of deaths in amyotrophic lateral sclerosis (ALS). The main cause of respiratory failure is pro bably diaphragmatic weakness. In order to test the correlation between respiratory impairment and diaphragmatic function we studied the phre nic nerve conduction in 31 ALS patients. Our results showed that patie nts with respiratory symptoms, and decreased forced vital capacity wit h arterial PaO2/PaCO2 abnormalities, had more commonly increased phren ic nerve latencies or absent response due to severe diaphragm denervat ion than ALS patients without respiratory complaints. Diaphragmatic pa resis commonly occurs during the course of ALS, and its presence and s everity can be assessed by phrenic nerve studies. It is important to r ecognize the development of impairment in diaphragmatic function in or der to prevent life-threatening complications.