Various Laryngeal Mechanisms in Controlling Voice Fundamental Frequency

一般认为，嗓音基频的肌肉控制主要由环甲肌完成。然而，据推测，人类产生的整个FO范围不能单独通过环甲膜活动获得。本研究旨在揭示控制FO的各种喉机制。本文对与FO变异相关的喉肌肌电活动进行了分析。这些结果被用于推测这些肌肉控制FO的机制。第一，crucialharyngeus（CP）表现出与FO的负相关，这表明该肌肉的收缩可以通过肌肉增厚和喉降低的综合作用使环状软骨向前旋转。第二，环杓外侧肌（LCA）与FO的相关性最高，表明内侧压迫力可以调节FO升高和降低时声带振动的有效长度。第三，环甲肌（CT）的斜部与FO的相关性高于直部，推测直部产生快速FO变化与喉发音清音相关，斜部的功能是独立于发音姿势扩大FO范围。这些推测的机制解释了所观察到的声带长度和FO之间的非线性关系。

It is generally considered that muscular control for voice fundamental frequency (FO) is preformed mainly by the cricothyroid muscle. However, it is assumed that the whole FO range produced by humans can not be obtaind by cricothyroid activity alone. This study is intended to reveal various laryngeal mehanisms in controlling FO. Electromyographical analyses were performed on the variations in EMG activity of some laryngeal muscles associated with FO variations in word utterances. The results wereused for speculating on the mechanisms of FO control by these muscles. First, the cricopharyngeus (CP) exhibits an inverse correlation with FO, suggesting that the contraction of this muscle can rotate the cricoid cartilage forward by a combined effect of the thickening of the muscle and larynx lowering. Second, the lateral cricoarytenoid (LCA) shows the highest correlation with FO, indicating that the medial compression force can adjust effective length of vocal fold vibration in FO rasing and FO lowering. Third, the oblique part of the cricothyroid (CT) has a higher correlation with FO than the straight part, and it is speculated that the straight part produces fast FO change associated with laryngeal articulation for devoicing and that the oblique part functions to expand fo range independently with articulatory gestures. These speculated mechanisms explain the observed non-linear relation between vocal fold length and FO.