Kinaesthetic Loss as a Marker for Spasmodic Dysphonia

描述（由申请人提供）：痉挛性发音困难（SD）是一种语音障碍，其特征是喉肌的不自主运动，导致语音中断和紧张或窒息的语音质量，并且可能严重损害交流。SD被认为起源于神经源性，并且与头部和颈部的局灶性肌张力障碍（FD）共享一些症状。SD的诊断已被证明是困难的，因为它经常表现出类似于肌肉紧张性发音困难（MTD）的症状。MTD是由异常发声引起的，据信是对声带组织肿胀的反应。误诊并不罕见，可能导致不适当的治疗。SD主要用肉毒杆菌毒素注射治疗，而MTD用行为疗法治疗。目前诊断的“黄金”标准采用一种复杂、耗时且昂贵的3步方法，包括问卷调查、临床感知评估和鼻内窥镜评估。最近的研究表明，患有影响头部和颈部肌肉组织的局灶性肌张力障碍（如眼睑痉挛和斜颈）的患者，其上肢的非肌张力障碍肌肉组织显示出动觉缺陷，这表明这些疾病的中心起源。因此，该建议背后的中心思想是检查SD是否也存在临床上无肌张力障碍的非肌张力障碍肢体系统中的动觉缺陷。这种联系从未建立，但我们的试验数据表明。相反，如果MTD患者肢体动觉正常，则动觉丧失将是SD的潜在标志物，有助于区分SD和MTD。我们的方法将是检查动觉敏锐度，通过确定精确的心理物理阈值检测手臂运动或区分手臂运动刺激-一个程序，从来没有被应用于SD患者。将SD与一般动觉缺陷联系起来的科学影响将增加FD和SD共享相似病理机制的证据，该病理机制改变了将外周本体感受信息与意志运动命令整合的中枢过程。显示SD而不是MTD与一般动觉丧失相关的健康意义在于，它开辟了开发易于管理、标准化、省时的SD（和FD）诊断临床试验的途径，补充了当前的诊断工具，并降低了误诊风险。

DESCRIPTION (provided by applicant): Spasmodic dysphonia (SD) is a voice disorder characterized by involuntary movement of laryngeal muscles that leads to voice breaks and a strained or strangled voice quality, and which can severely impair communication. SD is believed neurogenic in origin and shares some symptoms with focal dystonia (FD) of the head and neck. The diagnosis of SD has been proven to be difficult, because it often presents with symptoms similar to muscle-tension dysphonia (MTD). MTD is caused by abnormal phonation believed to be in response to swelling of vocal fold tissue. Misdiagnosis is not uncommon and can lead to inappropriate treatment. SD is treated primarily with botulinum toxin injections while MTD is treated with behavioral therapy. The current "gold" standard of diagnosis uses an elaborate, time-intensive, and costly 3-step approach involving questionnaire, a clinical-perceptual evaluation, and a nasoendoscopic evaluation. Recent research documented that patients with focal dystonia affecting head and neck musculature, such as blepharospasm and torticollis, reveal kinaesthetic deficits in the non-dystonic musculature of their upper limbs suggesting a central origin of these disorders. Thus, the central idea behind this proposal is to examine, if SD also presents with kinaesthetic deficits in non-dystonic limb systems that are clinically symptom-free. This link has never been established, but is suggested by our pilot data. If, in contrast, MTD patients have normal limb kinaesthesia, then kinaesthetic loss would be a potential marker for SD that could help to differentiate between SD and MTD. Our approach would be to examine kinaesthetic acuity by determining precise psychophysical thresholds for detecting arm motion or for discriminating between arm motion stimuli - a procedure that has never been applied to SD patients. The scientific impact of linking SD to a general kinaesthetic deficit would be increased evidence that FD and SD share a similar pathomechanism that alters the central process of integrating peripheral proprioceptive information with volitional motor commands. The health significance of showing that SD but not MTD is associated with a general kinaesthetic loss is that it opens the avenue to develop easy-to-administer, standardized, time-efficient clinical tests for the diagnosis of SD (and FD) that complements the current diagnostic arsenal and reduces the risk of a misdiagnosis.