Schillings M L, Kalkman J S, van der Werf S P, van Engelen B G M, Bleijenberg G, Zwarts M J
Department of Clinical Neurophysiology, University Medical Centre Nijmegen, Internal postal code 314, P.O. Box 9101, 6500 HB Nijmegen, Netherlands.
Clin Neurophysiol. 2004 Nov;115(11):2518-24. doi: 10.1016/j.clinph.2004.06.007.
We have investigated whether central activation failure (CAF) is increased during local muscle fatigue in chronic fatigue syndrome (CFS).
Fourteen female CFS patients and 14 age-matched healthy female controls made a 2 min sustained maximal voluntary contraction (MVC) of the biceps brachii muscle. Before, during, and after sustained MVC, electrical endplate stimulation was applied. Force and 5 channel surface EMG (sEMG) were registered.
Although force responses upon stimulation during rest did not differ between patients and controls, MVC was significantly lower in patients. Already at the beginning of sustained MVC, CFS patients showed significantly larger CAF than controls (36.5+/-17.0% and 12.9+/-13.3%, respectively). For all individual patients mean CAF over the first 45 s was higher than 30%, while it was below 30% for all controls. Less peripheral fatigue in patients was demonstrated by the changes in muscle fibre conduction velocity and the differences between force responses before and after contraction.
Central activation is diminished in CFS patients. Possible causes include changed perception, impaired concentration, reduced effort and physiologically defined changes, e.g. in the corticospinal excitability or the concentration of neurotransmitters. As a consequence, demands on the muscle are lower, resulting in less peripheral fatigue.
CFS patients show reduced central activation during MVC. The underlying pathophysiological processes remain still to be determined.
我们研究了慢性疲劳综合征（CFS）患者在局部肌肉疲劳期间中枢激活失败（CAF）是否增加。
14名女性CFS患者和14名年龄匹配的健康女性对照者对肱二头肌进行2分钟的持续最大自主收缩（MVC）。在持续MVC之前、期间和之后，施加电终板刺激。记录力量和5通道表面肌电图（sEMG）。
尽管静息时刺激后的力量反应在患者和对照者之间没有差异，但患者的MVC显著更低。在持续MVC开始时，CFS患者的CAF就显著高于对照者（分别为36.5±17.0%和12.9±13.3%）。对于所有个体患者，前45秒的平均CAF高于30%，而所有对照者均低于30%。肌肉纤维传导速度的变化以及收缩前后力量反应的差异表明患者的外周疲劳较少。
CFS患者的中枢激活减弱。可能的原因包括感知改变、注意力受损、努力程度降低以及生理上的改变，例如皮质脊髓兴奋性或神经递质浓度的改变。因此，对肌肉的需求较低，导致外周疲劳较少。
CFS患者在MVC期间中枢激活降低。潜在的病理生理过程仍有待确定。
