Van Asseldonk J T H, Van den Berg L H, Kalmijn S, Wokke J H J, Franssen H
Neuromuscular Research Group, Rudolf Magnus Institute of Neuroscience, Department of Clinical Neurophysiology, University Medical Centre Utrecht, The Netherlands.
Brain. 2005 Apr;128(Pt 4):880-91. doi: 10.1093/brain/awh375. Epub 2005 Feb 2.
The diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) is based on clinical and laboratory results and on features of demyelination found in nerve conduction studies. The criteria that are currently used to reveal demyelinative slowing in CIDP have several limitations. These criteria were only determined in lower arm and lower leg nerve segments, were not defined with respect to nerve temperature, and the relationship with distal compound muscle action potential (CMAP) amplitudes is unclear. The aim of our study was to determine criteria for demyelinative slowing for lower arm and leg segments as well as for upper arm and shoulder segments at a temperature of 37 degrees C, and to assess whether criteria have to be modified when the distal CMAP is decreased. Included were 73 patients with lower motor neuron disease (LMND), 45 patients with CIDP and 36 healthy controls. The arms and legs were warmed in water at 37 degrees C for at least 30 min prior to an investigation and thereafter kept warm with infrared heaters. The proposed criteria for demyelinative slowing were based on the maximum conduction slowing that may occur as a consequence of axonal degeneration and consisted of the upper boundary (99%) or the lower boundary (1%) of conduction values in LMND. In LMND, the maximum conduction slowing was different for arm and leg nerves and for segments within the arm nerves. Moreover, distal motor latency and motor conduction velocity were slower in nerves with distal CMAP amplitudes below 1 mV than in nerves with distal CMAP amplitudes above 1 mV. For these reasons, separate criteria were proposed for arm nerves, for leg nerves and for different segments within arm nerves, and more stringent criteria were proposed for distal motor latency and motor conduction velocity when the distal CMAP amplitude was below 1 mV. The diagnostic yield in CIDP was assessed using the nerve, and not the patient, as the unit of measurement. Thus, whether demyelinative slowing was present was determined for each nerve. Compared with other criteria, our criteria increased the specificity without affecting sensitivity. We conclude that the present criteria, based on the maximum slowing that may occur as a result of axonal degeneration, allow more accurate detection of demyelinative slowing in CIDP compared with other criteria. It should be emphasized that the proposed criteria can only be applied if the method of warming in water at 37 degrees C for at least 30 min is adopted.
慢性炎症性脱髓鞘性多发性神经病（CIDP）的诊断基于临床和实验室检查结果以及神经传导研究中发现的脱髓鞘特征。目前用于揭示CIDP中脱髓鞘性减慢的标准存在一些局限性。这些标准仅在手臂和腿部神经节段中确定，未针对神经温度进行定义，并且与远端复合肌肉动作电位（CMAP）幅度的关系尚不清楚。我们研究的目的是确定37摄氏度时手臂和腿部节段以及上臂和肩部节段的脱髓鞘性减慢标准，并评估当远端CMAP降低时标准是否必须修改。纳入了73名下运动神经元疾病（LMND）患者、45名CIDP患者和36名健康对照者。在检查前，将手臂和腿部在37摄氏度的水中加热至少30分钟，然后用红外线加热器保持温暖。提议的脱髓鞘性减慢标准基于轴突变性可能导致的最大传导减慢，由LMND中传导值的上边界（99%）或下边界（1%）组成。在LMND中，手臂和腿部神经以及手臂神经内各节段的最大传导减慢情况不同。此外，远端CMAP幅度低于1 mV的神经中的远端运动潜伏期和运动传导速度比远端CMAP幅度高于1 mV的神经慢。由于这些原因，针对手臂神经、腿部神经以及手臂神经内的不同节段提出了单独的标准，并且当远端CMAP幅度低于1 mV时，对远端运动潜伏期和运动传导速度提出了更严格的标准。以神经而非患者作为测量单位评估CIDP的诊断率。因此，针对每条神经确定是否存在脱髓鞘性减慢。与其他标准相比，我们的标准在不影响敏感性的情况下提高了特异性。我们得出结论，基于轴突变性可能导致的最大减慢的当前标准，与其他标准相比，能够更准确地检测CIDP中的脱髓鞘性减慢。应当强调的是，只有采用在37摄氏度的水中加热至少30分钟的方法，提议的标准才能适用。
