Electromyographic Study In Amyotrophic Lateral Sclerosis.

Object To study quantitative electromyography of patients with amyotrophic lateral sclerosis(ALS). Evaluate the sensitivity of different motor unit action potential(MUPs) parameters, spontaneous activity and the recruitment order in the quantitive electromyography of ALS. To determine electromyographic involvement and differences in groups of lower motor neurons in ALS patients with different initiative symptoms of onset, and the electromyographic defferences in patients of defferent clinical stages.Method Quantitative electromyography was performed in groups of lower motor neurons in 60 ALS patients with different initiative symptoms of onset, of defferent clinical stages and 55 matched normal control, to measure MUPs parameters, the presence of spontaneous activity was detected and the recruitment order was measured. Statistic analysis was used to compare MUPs parameters data in these two groups, abnormal rate of MUPs parameters, spontaneous activity, recruitment order in ALS patients, electromyographic involvement and differences in groups of lower motor neurons in ALS patients with different initiative symptoms of onset, and defferences in patients of defferent clinical stages were analysed.Conclusion Of the five MUPs parameters, area, duration and SI are more sensitive for evaluation of ALS, while polyphasia is of less sensitivity; spontaneous activity and recruitment order are less sensitive than MUPs parameters. It helps to detect evidence of neurogenic lesion in clinically unaffected muscles if all three are involved. In ALS patients, different initiative symptom of onset causes different distribution of electromyographic findings. Involvement of lumbosacral muscles is least frequent in patients with brainstem onset, while brainstem muscles in patients with lower limb onset. To find neurogenic activities, we can choose the corresponding motor neuron regions according to the initiative symptom of onset. In the cervical muscles and lumbosacral muscles, distal limb muscles should be examined first, while the brainstem muscles, sternocleidomastoid first.The electromyography of patients of defferent clinical stages differ. The most significant features in EMG in the very early stage of ALS are the fibrillations and positive sharp waves, if present, in quantitative EMG increased MUPs area and amplitude.