Frascarelli M, Rocchi L, Feola I
Dipartimento di Scienze Neurologiche, Università di Roma, Italy.
Muscle Nerve. 1988 Jul;11(7):757-61. doi: 10.1002/mus.880110712.
EMG power spectra obtained during a sustained isometric contraction were analyzed in a group of 10 children affected by Duchenne muscular dystrophy (DMD) and compared with those obtained in a control group of 5 normal children. In myopathic subjects the isometric contraction caused an increase of the total power, a progressive increase of power of the lower frequencies, a decrease of that of the higher frequencies, and a shift downward of the median frequency. In normal children an increase of the total power without a significant median frequency shift was noted. The modifications observed in DMD children were explained by a decrement of the firing rate of the more damaged fast twitch motor units. This decrease was probably induced by a relative predominance of activity of the slow twitch motor units, which are less damaged by the pathological process.
对一组10名患杜氏肌营养不良症（DMD）的儿童在持续等长收缩期间获得的肌电图功率谱进行了分析，并与5名正常儿童的对照组所获得的谱图进行了比较。在患有肌病的受试者中，等长收缩导致总功率增加、低频功率逐渐增加、高频功率降低以及中位频率向下偏移。在正常儿童中，观察到总功率增加但中位频率无明显偏移。在DMD儿童中观察到的这些变化可通过受损更严重的快肌运动单位放电率的降低来解释。这种降低可能是由慢肌运动单位活动的相对优势引起的，而慢肌运动单位受病理过程的损伤较小。
