Neuromuscular Diseases Unit, Kantonsspital St Gallen, St Gallen, Switzerland.
Clin Neurophysiol. 2011 Sep;122(9):1867-72. doi: 10.1016/j.clinph.2011.02.017. Epub 2011 Mar 10.
To investigate the intra-rater and inter-rater test-retest reliability of the Motor Unit Number Index (MUNIX) in healthy subjects in a multicentre setting.
Six study centres applied the MUNIX technique in 66 healthy subjects. Five to six muscles (biceps brachii, BB; abductor digiti minimi, ADM; abductor pollicis brevis, APB; tibialis anterior, TA; extensor digitorum brevis, EDB and abductor hallucis, AH) were measured in each volunteer four times by two independent examiners.
The method was easy to perform and well tolerated. The intraclass correlation coefficient (ICC) varied between centres and muscles. Intra-rater reliability was greatest for the AH (ICC 0.83) and EDB (ICC 0.81). Inter-rater reliability was greatest for the AH (ICC 0.69) and ADM muscles (ICC 0.69). The most critical muscle was the APB muscle (ICC 0.52, total variability). This was mostly due to variability in the compound muscle action potential (CMAP) measurements. MUNIX values of the APB, ADM and TA fell into the same range as in other motor unit number estimation (MUNE) studies.
MUNIX measurements in multiple muscles show good inter- and intra-rater reliability in healthy subjects. CMAP amplitude must be controlled to optimize reliability.
Results suggest that MUNIX could serve as a reliable marker for motor neuron loss in diseases like amyotrophic lateral sclerosis.
在多中心环境中，研究健康受试者中运动单位数量指数（MUNIX）的组内和组间重测信度。
6 个研究中心在 66 名健康受试者中应用 MUNIX 技术。每位志愿者的 5 至 6 块肌肉（肱二头肌、ADM；小指展肌、APB；胫骨前肌、EDB 和拇展肌、AH）由 2 位独立的检查者重复测量 4 次。
该方法易于操作且耐受性良好。组内相关系数（ICC）在中心和肌肉之间存在差异。AH（ICC 0.83）和 EDB（ICC 0.81）的内部分辨率最高。AH（ICC 0.69）和 ADM 肌肉的间部分辨率最高（ICC 0.69）。最关键的肌肉是 APB 肌肉（ICC 0.52，总变异性）。这主要是由于复合肌肉动作电位（CMAP）测量的变异性所致。APB、ADM 和 TA 的 MUNIX 值与其他运动单位数量估计（MUNE）研究中的值处于相同范围。
在健康受试者中，多块肌肉的 MUNIX 测量显示出良好的组内和组间重测信度。必须控制 CMAP 幅度以优化可靠性。
结果表明，MUNIX 可能成为肌萎缩侧索硬化症等疾病中运动神经元丢失的可靠标志物。
