Elble R J, Moody C, Higgins C
Department of Medicine, Southern Illinois University School of Medicine, Springfield 62794-9230.
Mov Disord. 1990;5(2):118-26. doi: 10.1002/mds.870050205.
Five patients exhibited severe tremor in the upper extremity, primarily when attempting to write or draw. Electromyography was performed to determine the patterns of muscle activity that were responsible for this tremor. Tremor was measured with an accelerometer and with a digitizing tablet. Two patients had postural tremor that was indistinguishable from mild, high-frequency essential tremor. All patients exhibited a severe 5-7-Hz tremor during the acts of writing and drawing. Muscles throughout the affected extremity exhibited rhythmic 5-7-Hz bursts of motor unit discharge, and the average level of motor unit activity was tonically increased in antagonistic muscles. This abnormal coactivation of antagonistic muscles produced subtle dystonic posturing of the affected limb that was overshadowed by severe tremor. Electromyography was useful in confirming the coexistence of tremor and dystonia in our patients. The nonspecificity of dystonia and postural tremor must be considered when discussing the nosology and pathophysiology of primary writing tremor.
五名患者上肢出现严重震颤，主要在试图书写或绘图时出现。进行了肌电图检查以确定导致这种震颤的肌肉活动模式。使用加速度计和数字化平板电脑测量震颤。两名患者出现姿势性震颤，与轻度高频特发性震颤难以区分。所有患者在书写和绘图时均表现出严重的5-7赫兹震颤。受影响肢体的所有肌肉均表现出有节奏的5-7赫兹运动单位放电爆发，拮抗肌的运动单位活动平均水平呈强直性增加。拮抗肌的这种异常共同激活导致受影响肢体出现轻微的肌张力障碍姿势，但被严重震颤掩盖。肌电图有助于证实我们患者中震颤和肌张力障碍的共存。在讨论原发性书写震颤的疾病分类和病理生理学时，必须考虑肌张力障碍和姿势性震颤的非特异性。
