Differential contributions of domain-general cerebellar timing mechanisms to temporal deficits in ataxic dysarthria

项目摘要/摘要 口语使用精确的亚秒级计时来标记音位对比、词汇重音差异 和短语界限，以及其他区别。共济失调是一种由以下原因引起的言语运动疾病 小脑受损或变性，并与各种暂时性缺陷有关，包括 对比语音中的时间类别和不规则语速和节奏。这些症状导致 语言自然度和清晰度下降，严重影响生活质量。而时间上的 共济失调构音障碍的症状已经确定，其根本原因尚不清楚，有 目前还没有循证的治疗方法来改善这一人群的语言清晰度和自然度。 这项提议中的实验测试了小脑的两个领域--一般功能的损害 导致共济失调构音障碍患者言语中时间缺陷的特定亚组。在第一个目标中，我们 测试对领域一般计时功能的损害如何导致产生分类时间的缺陷 反差很大。小脑参与了事件时序的控制，它处理单次事件的持续时间 或多个不规则事件，但不是相对定时，其处理多个常规事件的定时。这 导致不同类型的计时任务的知觉和产生的不同障碍。我们使用一种 在语音和非语音领域中确定哪些方面的感知和生产任务 语音定时由事件定时控制。检验对事件时间的控制在很大程度上影响 类别，而不是韵律特征，我们还将这些任务的性能与 说话有节奏性缺陷。 在第二个目标中，我们测试了对正向模型的维护和随之而来的损害是如何增加的 对反馈的依赖会导致语音节奏的改变和音段时长的过度变化。扬声器 持续监测他们自己的讲话，以确保他们准确地产生讲话目标；个人 小脑损伤表现出对暂时性延迟反馈的依赖增加，以纠正正在进行的 移动，而不是依赖于准确的生产向前模型。我们使用了两个改变的听觉反馈 测试元音目标实现中感知错误的时间效应的研究。我们确定的程度是 这种对空间精度反馈的依赖会干扰时间精度。我们也建立了关系 在这些实验中的时间扰动的大小和整个空间和时间之间 讲话不准确。 拟议的研究将确定领域通用时序障碍和 共济失调构音障碍患者反馈使用的变化对时间缺陷的影响。这是迈向 针对导致自然度和可理解性降低的特定损伤的治疗方法的开发 在这群人中。

Project Summary/Abstract Spoken language uses precise sub-second timing to mark phonemic contrasts, lexical stress differences, and phrasal boundaries, among other distinctions. Ataxic dysarthria is a speech motor disease caused by damage to or degeneration of the cerebellum and is linked to a variety of temporal deficits, including reduced contrast between temporal categories in speech and irregular speech rate and rhythm. These symptoms result in decreased speech naturalness and intelligibility, significantly impacting quality of life. While the temporal symptoms of ataxic dysarthria are well established, their underlying causes are poorly understood and there are currently no evidence-based treatments to improve speech intelligibility and naturalness in this population. The experiments in this proposal test how impairments to two domain-general functions of the cerebellum lead to specific subsets of temporal deficits in the speech of individuals with ataxic dysarthria. In the first aim, we test how damage to the domain-general timing function contributes to deficits in producing categorical temporal contrasts. The cerebellum is involved in the control of event timing, which deals with the duration of single even or multiple irregular events, but not in relative timing, which deals with the timing of multiple regular events. This leads to differential impairments in the perception and production of different types of timing tasks. We use a suite of perceptual and production tasks in both speech and non-speech domains to establish which aspects of speech timing are controlled by event timing. To test the hypothesis that the control of event timing largely affects categories but not prosodic characteristics, we also compare performance on these tasks with evaluations of rhythmic deficits in speech. In the second aim, we test how damage to the maintenance of forward models and consequent increased reliance on feedback lead to altered speech rhythm and overly variable segment durations. Speakers continuously monitor their own speech to ensure that they are accurately producing speech targets; individuals with cerebellar damage show increased dependence on temporally delayed feedback to correct ongoing movements, rather than relying on accurate forward models of production. We use two altered auditory feedback studies to test the temporal effects of perceived errors in vowel target attainment. We determine the extent to which reliance on feedback for spatial accuracy disturbs temporal accuracy. We also establish the relationship between the magnitude of temporal disturbances in these experiments and overall spatial and temporal inaccuracy in speech. The proposed studies will establish the respective contributions of domain-general timing impairments and changes in feedback use to temporal deficits in ataxic dysarthria. This is a critical first step towards the development of therapies that target the specific impairments that result in reduced naturalness and intelligibility in this population.