Richards C, Bouchard J P, Bouchard R, Barbeau H
Can J Neurol Sci. 1980 Nov;7(4):367-77. doi: 10.1017/s0317167100022897.
Dynamic muscle function was evaluated in nine patients with Friedreich's ataxia (FA) and eight with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). The measurement of torque throughout maximum voluntary isokinetic knee movements was used to quantitatively describe muscle weakness in the ataxic patients. Both FA and ARSACS patients were shown to have decreased dynamic strength in comparison to normal values during knee extension and flexion movements at 30 degrees/s. In the FA patients a lower torque-producing capacity was seen in the older patients. The electromyographic (EMG) activity was recorded in lower extremity muscles during the movements. In the vastus lateralis (VL), deviations from the normal EMG activation pattern were described in both groups of patients. A reduced amplitude in the EMG activity in the medial hamstrings (MH) was seen in the majority of the patients. An index of coactivation was defined by comparing the EMG activity when a muscle lengthened (antagonistic) to the EMG activity when the same muscle shortened (agonistic) during the isokinetic contractions. In comparison to normal values increased coactivation indexes were present in the VL and MH in patients of both groups. The characteristics of dynamic muscle strength and the activation of agonistic and antagonistic muscles described in the present study will provide the basis of evaluation for the effects of therapy in these patients.
对9例弗里德赖希共济失调（FA）患者和8例常染色体隐性遗传性夏勒沃魁-萨格奈痉挛性共济失调（ARSACS）患者的动态肌肉功能进行了评估。通过测量最大自主等速膝关节运动过程中的扭矩，定量描述共济失调患者的肌肉无力情况。结果显示，与正常值相比，FA和ARSACS患者在30度/秒的膝关节伸展和屈曲运动中动态力量均下降。在FA患者中，年龄较大的患者产生扭矩的能力较低。在运动过程中记录了下肢肌肉的肌电图（EMG）活动。在两组患者中，股外侧肌（VL）的EMG激活模式均偏离正常。大多数患者的内侧腘绳肌（MH）EMG活动幅度降低。共激活指数通过比较等速收缩过程中肌肉拉长（拮抗）时的EMG活动与同一肌肉缩短（主动）时的EMG活动来定义。与正常值相比，两组患者的VL和MH共激活指数均升高。本研究中描述的动态肌肉力量特征以及主动肌和拮抗肌的激活情况，将为评估这些患者的治疗效果提供依据。
