Amouzandeh Ali, Grossbach Michael, Hermsdörfer Joachim, Altenmüller Eckart
Institute of Music Physiology and Musicians' Medicine (IMMM), University of Music, Drama and Media, Emmichplatz 1, 30175 Hannover, Germany.
Institute of Human Movement Science, Department of Sport and Health Sciences, Technical University of Munich, Munich, Germany.
J Clin Mov Disord. 2017 Aug 8;4:13. doi: 10.1186/s40734-017-0060-4. eCollection 2017.
Writer's cramp (WC) is a task-specific focal dystonia which manifests itself as abnormal postures interfering with motor performance. As the spread of motor symptoms remains controversial and non-motor symptoms are widely discussed, in this exploratory study, we explore the pathophysiology of WC, focusing on task-specificity and the psychological profiles of WC patients.
In 14 right-handed WC patients and matched controls, we assessed motor control by applying motor performance tests (Vienna Test Series), as well as using writing analysis and grip-force measurements. Moreover, detailed psychological factors were assessed. Classification trees were used to distinguish patients from controls.
The total duration of writing and the vertical writing frequency of the pen are the most important variables to split the data set successfully into patients and controls. No other variables concerning motor performance tests, grip-force measurements or psychological factors correctly separated patients and controls.
Only variables from the writing tasks successfully separated patients and controls, indicating a strong task-specificity of WC in our patient group. Future research should be performed with larger samples of untreated WC patients in early stages of impairment, without any secondary motor disturbances, to verify our findings.
书写痉挛（WC）是一种特定任务性局灶性肌张力障碍，表现为干扰运动表现的异常姿势。由于运动症状的扩散仍存在争议，且非运动症状受到广泛讨论，在这项探索性研究中，我们探讨书写痉挛的病理生理学，重点关注任务特异性和书写痉挛患者的心理特征。
在14名右利手书写痉挛患者和匹配的对照组中，我们通过应用运动表现测试（维也纳测试系列）、书写分析和握力测量来评估运动控制。此外，还评估了详细的心理因素。使用分类树将患者与对照组区分开来。
书写总时长和笔的垂直书写频率是成功将数据集分为患者和对照组的最重要变量。关于运动表现测试、握力测量或心理因素的其他变量均不能正确区分患者和对照组。
只有来自书写任务的变量成功区分了患者和对照组，表明在我们的患者组中书写痉挛具有很强的任务特异性。未来的研究应以更大样本的未治疗书写痉挛患者为对象，在损伤早期且无任何继发性运动障碍的情况下进行，以验证我们的研究结果。
