Neilson P D, Andrews G, Guitar B E, Quinn P T
Brain Res. 1979 Dec 14;178(2-3):311-27. doi: 10.1016/0006-8993(79)90696-6.
Despite considerable speculation it remains unclear as to whether stretch reflexes perform a functional role in speech articulator muscles. Recent research, however, has shown that long loop stretch reflex mechanisms are brought into play during voluntary contraction of limb muscles and a functional role in oscillatory damping has been suggested. It was decided, therefore, to use a method and a technique of analysis similar to that used in limb muscles to search for tonic stretch reflex (TSR) responses in lip, tongue and jaw muscles during sustained voluntary contraction. The term 'action TSR' is used to differentiate stretch reflex responses measured from voluntary activity from those measured at rest. Simultaneous electromyogram (EMG) recordings were taken from the lip, tongue and jaw musculature in normal, stutterer and cerebral spastic subjects. Subjects were instructed to hold the appropriate articulator in a fixed position while the experiment applied an irregular, continuously changing, stretching force. The stretch and EMG signals were analyzed using a cross correlation and spectral analysis technique. This provided a sensitive means of detecting any EMG fluctuations which covaried with applied stretch and might therefore be classified as reflex. No suggestion of such action TSR responses could be found in lip or tongue muscles of any of the subjects tested, including the cerebral spastic subjects with dysarthric speech. It is therefore concluded that action TSR mechanisms are not operative in control of lip and tongue muscles in man. Furthermore, dysarthric speech in cerebral spasticity cannot be attributed to exaggerated tone of lip and tongue muscles resulting from hypersensitivity of TSR mechanisms. In contrast, clear action TSR responses were demonstrable in jaw closing muscles while in jaw opening muscles, small amplitude responses were detected but were not substantial in comparison with background activity. Since the action TSR is present in jaw and limb muscles, but absent in lip and tongue muscles, the suggestion of a functional role of this reflex in damping mechanical oscillations associated with inertial loads is further supported.
尽管存在诸多猜测，但目前仍不清楚牵张反射在言语发音肌肉中是否发挥功能作用。然而，最近的研究表明，在肢体肌肉的自主收缩过程中，长环牵张反射机制会被激活，并且有人提出其在振荡阻尼方面具有功能作用。因此，决定采用一种与用于肢体肌肉的分析方法和技术类似的方法，来寻找在持续自主收缩过程中唇、舌和颌部肌肉的紧张性牵张反射（TSR）反应。术语“动作TSR”用于区分从自主活动中测量到的牵张反射反应和在静息状态下测量到的反应。对正常受试者、口吃者和脑性痉挛患者的唇、舌和颌部肌肉组织进行了同步肌电图（EMG）记录。受试者被要求将相应的发音器官保持在固定位置，同时实验施加不规则的、持续变化的拉伸力。使用互相关和频谱分析技术对拉伸和EMG信号进行分析。这提供了一种灵敏的手段，用于检测与施加的拉伸相关的任何EMG波动，因此这些波动可能被归类为反射。在所测试的任何受试者的唇或舌肌肉中，包括患有构音障碍的脑性痉挛患者，均未发现这种动作TSR反应的迹象。因此得出结论，动作TSR机制在人类唇和舌肌肉的控制中不起作用。此外，脑性痉挛中的构音障碍不能归因于TSR机制过敏导致的唇和舌肌肉张力过高。相比之下，在闭口肌中可明显观察到清晰的动作TSR反应，而在开口肌中，检测到了小幅度反应，但与背景活动相比并不显著。由于动作TSR存在于颌部和肢体肌肉中，而在唇和舌肌肉中不存在，这进一步支持了这种反射在阻尼与惯性负荷相关的机械振荡中具有功能作用的观点。
