[Primary study of diaphragmatic electromyography in amyotrophic lateral sclerosis patients]

To investigate the features and application of diaphragmatic electromyography (DEMG) in amyotrophic lateral sclerosis (ALS) patients.

We recorded the electromyography of 43 diaphragms from 43 ALS patients by inserting concentric needle electrode from intercostal space, when they held their breath, breathed smoothly and drew deep breath, and took electromyography of 22 healthy diaphragms as controls. The percentage of forced vital capacity (%FVC) was performed simultaneously in 28 ALS patients.

All subjects showed no side-effect. The spontaneous activities could be found when ALS patients held their breath. During the period of their smooth breath, the duration of their diaphragmatic motor unit action potential (DMUAP) (12.1 ms +/- 2.7 ms) was longer than those of controls, and the common logarithmic value of the amplitude (2.585 +/- 0.132) and the area (2.722 +/- 0.208) of DMUAP were larger than those of controls. The percentage of polyphasic (53%) and satellite potential (5%) was also increased in ALS patients. The duration (13.6 ms +/- 3.6 ms) of the ALS patients with clinical dyspnoea was longer than that (11.6 ms +/- 2.2 ms) of others without it. The spontaneous activities were correlated with clinical dyspnoea and %FVC.

DEMG with needle electrode could evaluate the respiratory state of ALS patients at the level of electrophysiology. The duration and the spontaneous activity were its sensitive indexes.