Torres-Russotto Diego, Perlmutter Joel S
Department of Neurology, Washington University in St. Louis, St. Louis, Missouri 63110, USA.
Ann N Y Acad Sci. 2008 Oct;1142:179-99. doi: 10.1196/annals.1444.012.
Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements. Historically these peculiar postures were considered psychogenic but have now been classified as forms of dystonia. Writer's cramp is the most commonly identified task-specific dystonia and has features typical of this group of disorders. Symptoms may begin with lack of dexterity during performance of a specific motor task with increasingly abnormal posturing of the involved body part as motor activity continues. Initially, the dystonia may manifest only during the performance of the inciting task, but as the condition progresses it may also occur during other activities or even at rest. Neurological exam is usually unremarkable except for the dystonia-related abnormalities. Although the precise pathophysiology remains unclear, increasing evidence suggests reduced inhibition at different levels of the sensorimotor system. Symptomatic treatment options include oral medications, botulinum toxin injections, neurosurgical procedures, and adaptive strategies. Prognosis may vary depending upon body part involved and specific type of task affected. Further research may reveal new insights into the etiology, pathophysiology, natural history, and improved treatment of these conditions.
任务特异性肌张力障碍是原发性局灶性肌张力障碍，其特征是在选择性运动活动期间肌肉过度收缩，导致异常姿势，这些活动通常涉及高度熟练的重复性动作。从历史上看，这些特殊姿势曾被认为是心因性的，但现在已被归类为肌张力障碍的形式。书写痉挛是最常见的任务特异性肌张力障碍，具有这类疾病的典型特征。症状可能始于执行特定运动任务时缺乏灵活性，随着运动活动的持续，受累身体部位的姿势越来越异常。最初，肌张力障碍可能仅在诱发任务执行期间出现，但随着病情进展，也可能在其他活动甚至休息时发生。除了与肌张力障碍相关的异常外，神经系统检查通常无明显异常。虽然确切的病理生理学尚不清楚，但越来越多的证据表明感觉运动系统不同水平的抑制作用减弱。对症治疗选择包括口服药物、肉毒杆菌毒素注射、神经外科手术和适应性策略。预后可能因受累身体部位和受影响的特定任务类型而异。进一步的研究可能会揭示这些疾病的病因、病理生理学、自然史以及改进治疗方法的新见解。
