[Diaphragmatic motor evoked potential in amyotrophic lateral sclerosis patients].

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.