Welgampola M S, Colebatch J G
Institute of Neurological Sciences, Prince of Wales Hospital and Clinical School, Randwick, Sydney, New South Wales 2031, Australia.
Otol Neurotol. 2001 Nov;22(6):796-802. doi: 10.1097/00129492-200111000-00014.
Optimum stimulus parameters for tone burst-evoked myogenic responses can be defined. These optimized responses will be similar to those evoked by clicks in the same subjects.
Loud tones give rise to myogenic responses in the anterior neck muscles, similar to click-evoked potentials, and are likely to be saccular in origin.
Tone burst-evoked and click-evoked myogenic potentials were measured from the sternocleidomastoid muscles of 12 normal subjects (6 men, 6 women) during tonic activation. The effects of tone burst frequency and duration were systematically investigated. Thresholds were measured and compared with click thresholds for the same subjects. Patients with specific lesions were studied using both stimuli.
Tone burst-evoked responses showed frequency tuning, with the largest reflex amplitudes at either 500 Hz or 1 kHz. As the stimulus duration was increased, using a constant repetition rate, there was an increase in the reflex amplitudes followed by a decline. The overall optimum stimulus duration was 7 milliseconds. The mean tone burst threshold was 114.4-dB sound pressure level. Stimulus thresholds for click-evoked and tone burst-evoked responses were significantly correlated. Tone burst-evoked and click-evoked responses were present after stimulation of the affected ears of subjects with profound sensorineural hearing loss. Four subjects who had previously undergone vestibular neurectomy had an absence of click and tone burst-evoked responses on the side of the lesion, confirming their vestibular dependence.
Tone burst-evoked myogenic responses are similar to click-evoked responses but require lower absolute stimulus intensities. To be certain of an optimum response, a stimulus duration of 7 milliseconds, an adequate intensity, and frequencies of both 500 Hz and 1 kHz should be used.
可以确定短纯音诱发肌源性反应的最佳刺激参数。这些优化后的反应将与同一受试者中短声诱发的反应相似。
高强度纯音可引起颈部前方肌肉的肌源性反应，类似于短声诱发电位，其起源可能为球囊。
在12名正常受试者（6名男性，6名女性）的胸锁乳突肌处于紧张性激活状态时，测量短纯音诱发和短声诱发的肌源性电位。系统研究了短纯音频率和持续时间的影响。测量阈值并与同一受试者的短声阈值进行比较。使用两种刺激对患有特定病变的患者进行研究。
短纯音诱发反应呈现频率调谐，在500 Hz或1 kHz时反射幅度最大。在重复率恒定的情况下，随着刺激持续时间的增加，反射幅度先增大后减小。总体最佳刺激持续时间为7毫秒。短纯音的平均阈值为114.4 dB声压级。短声诱发反应和短纯音诱发反应的刺激阈值显著相关。在患有重度感音神经性听力损失的受试者患侧耳受到刺激后，可出现短纯音诱发和短声诱发反应。4名先前接受过前庭神经切除术的受试者在病变侧没有短声和短纯音诱发反应，证实了这些反应对前庭的依赖性。
短纯音诱发的肌源性反应与短声诱发的反应相似，但所需的绝对刺激强度较低。为确保获得最佳反应，应使用7毫秒的刺激持续时间、足够的强度以及500 Hz和1 kHz的频率。
