Aggarwal Arun
Department of Neurology, Concord Hospital, Concord, NSW 2139, Australia.
Neurol Res Int. 2012;2012:187947. doi: 10.1155/2012/187947. Epub 2012 May 9.
In slowly progressive conditions, such as motor neurone disease (MND), 50-80% of motor units may be lost before weakness becomes clinically apparent. Despite this, maximal voluntary isometric contraction (MVIC) has been reported as a clinically useful, reliable, and reproducible measure for monitoring disease progression in MND. We performed a study on a group of asymptomatic subjects that showed a lack of correlation between isometric grip strength and thenar MUNE. Motor unit number estimation (MUNE) estimates the number of functioning lower motor neurones innervating a muscle or a group of muscles. We used the statistical electrophysiological technique of MUNE to estimate the number of motor units in thenar group of muscles in 69 subjects: 19 asymptomatic Cu, Zn superoxide dismutase 1 (SOD 1) mutation carriers, 34 family controls, and 16 population controls. The Jamar hand dynamometer was used to measure isometric grip strength. This study suggests that MUNE is more sensitive for monitoring disease progression than maximal voluntary isometric contraction (MVIC), as MUNE correlates with the number of functional motor neurones. This supports the observation that patients with substantial chronic denervation can maintain normal muscle twitch tension until 50-80% of motor units are lost and weakness is detectable.
在诸如运动神经元病（MND）等缓慢进展性疾病中，在临床上出现肌无力之前，50%至80%的运动单位可能已经丧失。尽管如此，最大自主等长收缩（MVIC）已被报道为监测MND疾病进展的一种临床有用、可靠且可重复的测量方法。我们对一组无症状受试者进行了一项研究，结果显示等长握力与鱼际肌运动单位数目估计（MUNE）之间缺乏相关性。运动单位数目估计（MUNE）用于估计支配一块肌肉或一组肌肉的功能性下运动神经元的数量。我们使用MUNE的统计电生理技术来估计69名受试者鱼际肌群的运动单位数量，其中包括19名无症状的铜锌超氧化物歧化酶1（SOD 1）突变携带者、34名家族对照者和16名人群对照者。使用贾马尔握力计测量等长握力。这项研究表明，由于MUNE与功能性运动神经元的数量相关，因此MUNE在监测疾病进展方面比最大自主等长收缩（MVIC）更敏感。这支持了以下观察结果：患有严重慢性失神经支配的患者在50%至80%的运动单位丧失且可检测到肌无力之前，能够维持正常的肌肉抽搐张力。
