A study on production mechanism of pathological voice

声带振动模式对嗓音质量的贡献主要是在正常受试者身上进行的。因为我们一直用来监测振动的工具是频闪显微镜，当振动是规则的时候，频闪显微镜可以给出振动模式的想法。然而，如果是病态的声音，不能保证振动是规则的。假设振动是不规则的，这是相当自然的。为了了解生产机理，有必要拥有一种具有高时间分辨率的专用工具。我们一直在开发高速数字成像系统，使我们能够以高达9000帧/秒的速度监测声带振动。利用该系统，我们可以直观地看到有病变的声带中的病理振动模式。我们研究了我们在喉部麻痹病例中有时会遇到的重发音的产生机制。在重发音的情况下，两侧的声带v…具有不同频率的更多的脊椎动物。因此，周期性地观察到声门完全闭合，导致声学幅度的波动。由于振幅起伏是准周期的，我们感觉到了两种不同的音高。一个是基频，另一个是调制频率。另一种常见的病理是痉挛性发音困难，它被认为是声带上的肌张力障碍。痉挛性发音障碍患者发出的声音的听觉印象表现为紧张、吱吱、间歇性等。这些病态的音质会定期被听到。我们监测了异常声音瞬间的振动模式。振动周期闭合周期长，开放相短，声带漂移小。这种振动产生低沉的音调和非常粗糙的印象，类似于声带的声音印象。我们推测痉挛性发音障碍的病理生理学机制是声带过度内收，导致声门紧密闭合，这提示了通过注射肉毒毒素来减弱声带内收力的治疗思路。较少

The contribution of the vocal folds vibration pattern to voice quality has been investigated mainly on normal subjects. Because tools we have been applying to monitor the vibration is stroboscope and the stroboscope can give the idea of the vibration pattern when the vibration is regular. However, in case of pathological voice, there are no guarantee that the vibration is regular. It is rather natural to assume that the vibration is irregular. In order to understand the production mechanism, it is essential to have a special tool with high temporal resolution. We have been developing the high speed digital imaging system which allows us to monitor the vocal fold vibration with up to 9000 frame per sec. By utilizing this system, we could visualize the pathological vibration pattern seen in the vocal folds with some lesions. We investigated the production mechanism of the diplophonia which we sometime experience in laryngeal palsy cases. In diplophonia case, the vocal fold on each side v … More ibrates with different frequency. As a result, complete glottal closure is observed periodically resulting in the fluctuation of the acoustic amplitude. Since the amplitude fluctuation is quasi-periodic, we percept two different pitch. One is the fundamental frequency and the other is the modulation frequency. Another puqqling pathology is spasmodic dysphonia which is supposed to be dystonia on the vocal folds. Acoustic impression of the voice uttered by patients with spasmodic dysphonia is expressed as strained, creaky, intermittent and so forth. Those pathological voice quality is heard periodically. We monitored the vibration pattern at the moment of the abnormal voice. The vibration cycle has a long closed period and short open phase with small excursion of the vocal fold. This vibration produces the low tone and very rough impression which is similar to the acoustic impression of the vocal fry. We suppose that the pathophysiology of spasmodic dysphonia is hyperadduction of the vocal folds resulting in the tight glottal closure which suggest the therapeutic idea to weaken adduction force of the folds by injection of botulinum toxin. Less