Kinaesthetic Loss as a Marker for Spasmodic Dysphonia

描述（由申请人提供）：痉挛性发声障碍（SD）是一种声音障碍，其特征是喉部肌肉的不自主运动，导致声音中断，声音质量紧张或窒息，严重影响沟通。SD被认为是神经源性的，并与头颈部局灶性肌张力障碍（FD）有一些相同的症状。诊断SD已被证明是困难的，因为它通常表现出类似于肌张力性发声障碍（MTD）的症状。MTD是由声带组织肿胀引起的异常发声引起的。误诊并不罕见，并可能导致不适当的治疗。SD主要通过注射肉毒杆菌毒素进行治疗，而MTD则通过行为疗法进行治疗。目前的“黄金”诊断标准采用一种复杂、耗时且昂贵的三步方法，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，局灶性肌张力障碍患者影响头颈部肌肉组织，如眼睑痉挛和斜颈，显示上肢非肌张力障碍的动觉缺陷，提示这些疾病的中心起源。因此，本建议的中心思想是检查SD是否在无临床症状的非张力障碍肢体系统中也表现出运动感缺陷。这种联系从未得到证实，但我们的试验数据表明了这一点。相反，如果MTD患者有正常的肢体运动感，那么运动感丧失将是SD的潜在标志，可以帮助区分SD和MTD。我们的方法是通过确定检测手臂运动或区分手臂运动刺激的精确心理物理阈值来检查动觉敏锐度——这一过程从未应用于SD患者。将SD与一般动觉缺陷联系起来的科学影响将增加证据，证明FD和SD具有相似的病理机制，即改变将外周本体感觉信息与意志运动命令整合的中央过程。显示SD而非MTD与一般动觉性丧失相关的健康意义在于，它为开发易于管理、标准化、高效的SD（和FD）诊断临床测试开辟了道路，补充了当前的诊断库，降低了误诊的风险。

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.