P78-F Can we predict respiratory failure in patients with Amyotrophic Lateral Sclerosis (ALS) electrophysiologically?

Abstract

In ALS, respiratory complications are important in the prognosis of the disease. The aim of this study was to determine the electrophysiological findings that may predict respiratory failure. According to the Awaji electrodiagnostic criteria, 30 patients with ALS who were diagnosed as definite or probable ALS but without respiratory failure were included in the study. The patients were examined at intervals of 2–4 months. Neurological examination, nerve conduction studies, needle electromyography (EMG), pulmonary function test, electromyography of swallowing, arterial blood gas analysis and single breath count test were performed in all patients. Patients were followed until respiratory failure developed. One year follow-up, 17 patients developed respiratory distress. Neurological examinations and other tests were performed on average 3 times. The most sensitive finding that predicted respiratory failure was found to be neurogenic EMG recordings detected in sternocleidomastoid (SCM) muscle. It was observed that respiratory distress developed just after the participation of SCM and rectus abdominis muscles in the respiratory system. The reduction in the phrenic nerve compound muscle action potential amplitude is directly correlated to dyspnea, but its sensitivity is low. There is no sensitive biomarker predicting respiratory distress in patients with ALS. Although the number of cases in our study is not sufficient, neurogenic EMG findings in some muscles (such as SCM) and the participation of SCM and Rectus abdominis muscles to the respiration may be predictive for dyspnea. Although there are many studies related to ALS, there is no reliable test for early detection of respiratory failure. Further studies are needed.