The difference in the diaphragmatic physiological measures between inspiratory and expiratory phases in ALS.

Introduction: We aimed to clarify the differences in static and dynamic diaphragm parameters between the expiratory and inspiratory phases in amyotrophic lateral sclerosis (ALS).

Methods: Twenty patients with early-stage ALS and 16 healthy controls were enrolled in the study. We measured the amplitudes of compound muscle action potential (phCMAP) by electrical stimulation of the phrenic nerve and the zone of apposition wall thickness of the diaphragm (DT) using ultrasonography.