Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan; Department of Molecular Pathobiology of Brain Disease, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Clin Neurophysiol. 2023 Feb;146:124-130. doi: 10.1016/j.clinph.2022.12.004. Epub 2022 Dec 22.
To elucidate the utility of the proximal to distal compound muscle action potential (CMAP) duration ratio to distinguish between demyelinating Charcot-Marie-Tooth disease (CMT) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) compared with nerve ultrasound.
Thirty-nine demyelinating CMT patients and 19 CIDP patients underwent nerve conduction studies (NCS) and nerve ultrasound. NCS parameters including CMAP duration ratio calculated by dividing the value at the proximal site by that at the distal site and nerve cross-sectional area (CSA) measured by ultrasound were compared between the two groups. The diagnostic sensitivity and specificity of each parameter were analysed.
CMT patients showed a significantly lower CMAP duration ratio than CIDP patients (p < 0.05). The area under the curve (AUC) value of the CMAP duration ratio exceeded 0.95 when CMT was considered "positive", and a cut-off value of 1.13 resulted in high diagnostic sensitivity and specificity (84.6 and 100 % for median nerve, 97.4 and 85.7 % for ulnar nerve, respectively), whereas the AUC value of nerve CSA ranged from 0.70 to 0.81.
The CMAP duration ratio could effectively distinguish between demyelinating CMT and CIDP.
Adding the CMAP duration ratio to a routine NCS may improve the accuracy of the diagnosis of demyelinating CMT.
探讨与神经超声相比，近端至远端复合肌肉动作电位（CMAP）时程比在鉴别脱髓鞘性夏科-马里-图思病（CMT）和慢性炎症性脱髓鞘性多发性神经病（CIDP）中的作用。
39 例脱髓鞘性 CMT 患者和 19 例 CIDP 患者接受了神经传导研究（NCS）和神经超声检查。比较两组患者的 NCS 参数，包括通过近端部位值除以远端部位值计算得出的 CMAP 时程比和超声测量的神经横截面积（CSA）。分析每个参数的诊断灵敏度和特异性。
CMT 患者的 CMAP 时程比明显低于 CIDP 患者（p<0.05）。当将 CMT 视为“阳性”时，CMAP 时程比的曲线下面积（AUC）值超过 0.95，而 1.13 的截断值具有较高的诊断灵敏度和特异性（正中神经为 84.6%和 100%，尺神经为 97.4%和 85.7%），而神经 CSA 的 AUC 值范围为 0.70 至 0.81。
CMAP 时程比可有效鉴别脱髓鞘性 CMT 和 CIDP。
在常规 NCS 中添加 CMAP 时程比可能会提高脱髓鞘性 CMT 的诊断准确性。
