Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children National Health Service (NHS) Foundation Trust, London WC1N 3JH, UK.
Int J Mol Sci. 2018 Feb 22;19(2):624. doi: 10.3390/ijms19020624.
The function of the neuromuscular junction in children is amenable to electrophysiological testing. Of the two tests available, repetitive nerve stimulation is uncomfortable and has a reduced sensitivity compared with single-fibre methodology. The latter is the method of choice, recording the variability in neuromuscular transmission as a value called jitter. It can be performed by voluntary activation of the muscle being examined, which is not suitable in children, or by stimulation techniques. A modification of these techniques, called Stimulated Potential Analysis with Concentric needle Electrodes (SPACE), is well tolerated and can be performed while the child is awake. It has a high sensitivity (84%) for the diagnosis of neuromuscular transmission disorders, the majority of which are myasthenic syndromes, and a moderate specificity (70%). The latter can be improved by the exclusion of neurogenic causes and the determination of the degree of jitter abnormality. Minor jitter abnormalities, under 115% of the upper limit of normal, are usually caused by myopathies with an associated neuromuscular transmission disorder, whereas levels higher than this value are usually associated with one of the myasthenic conditions.
儿童的神经肌肉接头功能可进行电生理测试。在现有的两种测试中，重复神经刺激既不舒服，其敏感性也比单纤维方法降低。后者是首选方法，通过记录称为抖动的神经肌肉传递变异性来进行。它可以通过自愿激活正在检查的肌肉来完成，但这在儿童中并不适用，或者通过刺激技术来完成。这些技术的一种改进方法，称为同心针电极刺激电位分析 (SPACE)，耐受性良好，并且可以在儿童清醒时进行。它对神经肌肉传递障碍的诊断具有很高的敏感性（84%），其中大多数是肌无力综合征，并且具有中等特异性（70%）。通过排除神经源性原因和确定抖动异常程度，可以提高后者的特异性。小于正常值上限的 115%的微小抖动异常通常是由伴有神经肌肉传递障碍的肌病引起的，而高于该值的水平通常与肌无力症之一有关。
