Ravits J, Hallett M, Baker M, Wilkins D
Neurology. 1985 Sep;35(9):1387-91. doi: 10.1212/wnl.35.9.1387.
Four patients with primary writing tremor had a focal, task-specific tremor that responded to anticholinergic drugs. Physiologic features included EMG activity alternating in antagonist muscles, 5- to 20-microV cerebral potentials evoked by stretch of pronator teres, and no C-reflexes. Another patient had myoclonic jerks of the forearm on attempts to write ("myoclonic writer's cramp") that also responded to anticholinergic drugs; EMG activity appeared synchronously or alternating in antagonist muscles. These disorders have features of dystonia and enlarge the spectrum of writer's cramp.
四名原发性书写震颤患者出现局灶性、任务特异性震颤，对抗胆碱能药物有反应。生理特征包括拮抗肌中肌电图活动交替、旋前圆肌伸展诱发的5至20微伏脑电位，且无C反射。另一名患者在试图书写时出现前臂肌阵挛性抽搐（“肌阵挛性书写痉挛”），对抗胆碱能药物也有反应；肌电图活动在拮抗肌中同步或交替出现。这些疾病具有肌张力障碍的特征，扩大了书写痉挛的范围。
