Ackermann H, Hertrich I, Scharf G
Department of Neurology, University of Tübingen, Germany.
J Speech Hear Res. 1995 Dec;38(6):1252-9. doi: 10.1044/jshr.3806.1252.
The present study investigates the influence of cerebellar disorders on articulatory performance. A linear trend between peak velocity and movement amplitude seems to represent a basic organizational principle both of upper limb and speech motor control. This relationship is preserved in arm movements of patients with cerebellar dysfunction. However, these subjects show a decreased slope of the respective regression lines under the instruction to perform movements as fast as possible. In order to find out whether these findings also hold for speech motor control, peak velocity, range, and duration both of the opening and closing gestures during production of /pap/- as well as /pa:p/-sequences-embedded into a carrier phrase each-were measured using an optoelectric system. In addition, vowel length (/a/, /a:/) was determined at the acoustic speech signal: (a) The cerebellar patients showed a prolongation of both vowel targets. Most of them, nevertheless, presented with discernible durational contrasts; (b) The articulatory gestures were characterized by a highly linear relationship between peak velocity and movement range in the cerebellar as well as in the control group; (c) As a rule, the cerebellar subjects had decreased velocity-displacement ratios as compared to the normals; (d) The discrepancy in slope of the computed regression lines between the controls and the patients varied according to the type of movement (opening vs. closing gesture) and-to a lesser decree-linguistic demands (short vs. long vowel). These data indicate an impaired ability of cerebellar patients to increase muscular forces in order to produce adequately scaled articulatory gestures of short duration.
本研究调查了小脑疾病对发音表现的影响。峰值速度与运动幅度之间的线性趋势似乎代表了上肢和言语运动控制的基本组织原则。这种关系在小脑功能障碍患者的手臂运动中得以保留。然而，在被要求尽可能快速地进行运动时，这些受试者各自回归线的斜率降低。为了弄清楚这些发现是否也适用于言语运动控制，使用光电系统测量了在发出/pap/以及/pa:p/序列（每个序列都嵌入到一个载体短语中）时，开合手势的峰值速度、范围和持续时间。此外，在声学语音信号中确定了元音长度（/a/，/a:/）：（a）小脑疾病患者的两个元音目标都延长了。然而，他们中的大多数人仍表现出可辨别的时长对比；（b）发音手势的特点是，在小脑疾病患者组和对照组中，峰值速度与运动范围之间都存在高度线性关系；（c）通常，小脑疾病患者的速度 - 位移比低于正常人；（d）对照组和患者组之间计算出的回归线斜率差异因运动类型（开合手势）以及在较小程度上因语言要求（短元音与长元音）而异。这些数据表明，小脑疾病患者增加肌肉力量以产生持续时间足够短且幅度适当的发音手势的能力受损。
