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Objective: To investigate the features and application of diaphragmatic electromyography (DEMG) in amyotrophic lateral sclerosis (ALS) patients., Methods: 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., Results: 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., Conclusion: 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.

Objective: To investigate the features and application of diaphragmatic motor evoked potential (DMEP) in amyotrophic lateral sclerosis (ALS) patients., Methods: To record the latency and amplitude of diaphragmatic compound muscle action potential (DCMAP) from 37 ALS patients and 31 control subjects with surface electrodes after transcranial and transcervical magnetic stimulation, central motor conduction time (CMCT) was calculated. The percentage of forced vital capacity (%FVC) was performed in 22 ALS patients simultaneously., Results: Cortical and cervical latencies of the ALS patients were longer than those of the controls, and cortical and cervical amplitudes of the ALS patients were lower than those of the controls. CMCT of the ALS patients were longer than that of the controls. Cortical latency, cortical amplitude and CMCT were all correlated with the dysfunction of the pyramidal tract. Cortical latency and CMCT were also correlated with the clinical respiratory dysfunction, cervical latency was correlated with %FVC., Conclusions: CMCT, Cortical and cervical latencies are sensitive index in DMEP parameters reflecting respiratory dysfunction in ALS, CMCT reflects cortical spinal tract function of ALS patients associated with respiration. It would be helpful to detect the neurological basis of the respiratory disturbance in ALS combining CMCT with cervical latency.

Objective: To investigate the features and application of phrenic nerve conduction in amyotrophic lateral scle-rosis (ALS) patients., Methods: The latency and amplitude of diaphragmatic compound muscle action potential (DCMAP) were recorded among 44 ALS patients and 31 control subjects with surface electrodes after the cervical part of phrenic nerve was stimulated with electricity. The percentage of forced vital capacity (%FVC) was examined in 28 ALS patients simultaneously., Results: Right and left phrenic distal motor latencies (PDML) of ALS patients were 8.4 ms +/- 2.2 ms and 7.6 ms +/- 1.4 ms respectively, longer than those of the controls, and the logarithmic value of amplitudes among ALS patients was 2.68 +/- 0.37, lower than that among the controls. Take the right side for example, although PDML was correlated with %FVC, it had no correlation with clinical respiratory dysfunction. Neither %FVC nor clinical respiratory dysfunction was correlated with the amplitude of DCMAP. The rate of abnormal PDML (47.7%) was higher than the rate of clinical dyspnea (25%)., Conclusion: PDML is a sensitive index in phrenic conduction parameter reflecting respiratory dysfunction in ALS. Only when the PDML is combined with the central motor conduction time of the diaphragmatic motor evoked potential the nervous system basis of the respiratory disturbance in ALS can be revealed.