Motor unit number in a small facial muscle, dilator naris.
Motor unit number in a small facial muscle, dilator naris.
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DOI：
10.1007/s00221-015-4359-9
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发表时间：
2015-10
影响因子：
2
通讯作者：
Fregosi RF
中科院分区：
文献类型：
--
作者：
Patel-Khurana N;Fregosi RF
运动单元功能的丧失是许多神经肌肉疾病的根本原因。面神经支配面部表情肌肉，包括鼻肌，它在气流阻力的调节中也起着重要的作用。由于面部肌肉难以单独激活，因此很难准确评估面部肌肉的运动单元数。在这里，我们应用手动McComas方法来估计在鼻扩张肌运动单位的数量。对26例（12 M/14 F）年龄20 ~ 41岁的受试者进行面神经颧支分级刺激，记录其肌电图。每个受试者在不同的日子进行两次研究，以评估方法的可重复性。作为对McComas方法使用的检验，我们还估计了6名受试者的第一背骨间肌（FDI）的运动单位数，因为该肌肉也很小，并已使用McComas方法进行了研究。用严格的统计学方法Bland-Altman程序评估再现性。我们估计，与FDI的144±35.5个运动单元相比，扩张肌由75±15.6 （SD）个运动单元组成。扩张肌运动单元估计的复测再现性变异系数为29.6%，与其他肌肉的单日再现性相似。采用表面电极进行记录和刺激，记录质量高，重现性好。这项简单的技术可以应用于临床上跟踪运动神经元的丢失，并监测面神经的完整性。
A loss of functioning motor units underlies many neuromuscular disorders. The facial nerve innervates the muscles of facial expression, including nasal muscles, which also play an important role in the regulation of airflow resistance. It is difficult to accurately assess motor unit number in the facial muscles, because the muscles are difficult to activate in isolation. Here we apply the manual McComas method to estimate the number of motor units in a nasal dilator muscle. EMG of the dilator naris was recorded during graded stimulation of the zygomatic branch of the facial nerve in 26 subjects (12 M/14 F), aged 20–41 years. Each subject was studied twice, on separate days, to estimate method reproducibility. As a check on our use of the McComas method, we also estimated motor unit number in the first dorsal interosseus muscle (FDI) of 6 subjects, as the muscle is also small, and has been studied with the McComas method. Reproducibility was evaluated with a rigorous statistical approach, the Bland-Altman procedure. We estimate that dilator naris is composed of 75 ±15.6 (SD) motor units, compared to 144 ± 35.5 in FDI. The coefficient of variation for test-retest reproducibility of dilator naris motor unit estimates was 29.6%, similar to separate-day reproducibility reported for other muscles. Recording and stimulation were done with surface electrodes, and the recordings were of high quality and reproducible. This simple technique could be applied clinically to track motor neuron loss, and to monitor facial nerve integrity.