OBJECTIVE Isolated focal dystonia can spread to muscles beyond the initially affected body region, but risk of spread has not been evaluated in a prospective manner. Furthermore, body regions at risk for spread and the clinical factors associated with spread risk are not well characterised. We sought here to prospectively characterise risk of spread in recently diagnosed adult-onset isolated focal dystonia patients. METHODS Patients enrolled in the Dystonia Coalition with isolated dystonia affecting only the neck, upper face, hand or larynx at onset of symptoms were included. Timing of follow-up visits was based on a sliding scale depending on symptom onset and ranged from 1 to 4 years. Descriptive statistics, Kaplan-Meier survival curves and Cox proportional hazard regression models were used to assess clinical characteristics associated with dystonia spread. RESULTS 487 enrolled participants (68.3% women; mean age: 55.6±12.2 years) met our inclusion/exclusion criteria. Spread was observed in 50% of blepharospasm, 8% of cervical dystonia, 17% of hand dystonia and 16% of laryngeal dystonia cases. Most common regions for first spread were the oromandibular region (42.2%) and neck (22.4%) for blepharospasm, hand (3.5%) for cervical dystonia and neck for hand (12.8%) and laryngeal (15.8%) dystonia. Increased spread risk was associated with a positive family history (HR=2.18, p=0.012) and self-reported alcohol responsiveness (HR=2.59, p=0.009). CONCLUSIONS Initial body region affected in isolated focal dystonia has differential risk and patterns of spread. Genetic factors likely influence the risk of spread. These findings can aid clinical prognostication and inform future investigations into potential disease-modifying treatments.

中文翻译：

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成年发作的孤立性局灶性肌张力障碍传播的风险：一项前瞻性国际队列研究。

目的孤立性局灶性肌张力障碍可以扩散到最初受影响的身体区域以外的肌肉，但是尚未以前瞻性的方式评估其扩散风险。此外，没有很好地表征处于传播危险中的身体部位以及与传播风险相关的临床因素。我们在这里寻求前瞻性地表征在最近诊断的成年发作的孤立性局灶性肌张力障碍患者中传播的风险。方法入选肌张力障碍联盟的患者，仅在症状发作时仅影响颈部，上面部，手或喉部的孤立性肌张力障碍。随访的时间根据症状的发作而定，范围为1至4年。描述性统计，Kaplan-Meier生存曲线和Cox比例风险回归模型用于评估与肌张力障碍扩散相关的临床特征。结果487名登记的受试者（68.3％的女性；平均年龄：55.6±12.2岁）符合我们的纳入/排除标准。在50％的睑缘痉挛，8％的宫颈肌张力障碍，17％的手肌张力障碍和16％的喉肌张力障碍病例中观察到传播。初发最常见的区域是眼睑痉挛的下颌骨区域（42.2％）和颈部（22.4％），宫颈肌张力障碍的手（3.5％）和手部颈部的颈椎肌张力障碍（12.8％）和喉部肌张力障碍（15.8％）。传播风险增加与家族史阳性（HR = 2.18，p = 0.012）和自我报告的酒精反应（HR = 2.59，p = 0.009）相关。结论受孤立性局灶性肌张力障碍影响的初始身体区域具有不同的风险和传播方式。遗传因素可能会影响传播的风险。这些发现可以帮助临床预后，并为将来对潜在疾病缓解疗法的研究提供参考。