Comparison of Motor Nerve Conduction Findings in Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Charcot-Marie-Tooth Disease Type 1

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired immune-mediated disorder characterized by weakness and sensory deficits. Charcot-Marie- Tooth type 1 (CMT1) is a slowly progressive hereditary degenerative disease. This study quantitatively analyzed the electrophysiological characteristics observed in motor nerve conduction studies for both diseases. This retrospective study included 80 patients diagnosed with CIDP (n=47) or CMT1 (n=33) and healthy controls (n=77). This study conducted a stepwise analysis of distal compound muscle action potential (dCMAP) amplitude, motor nerve conduction velocity (MNCV), proximal/distal CMAP amplitude ratio, and correlation analysis of MNCV. CMT1 showed more severe polyneuropathy than CIDP according to the no-potential rate, dCMAP amplitude, or MNCV. Statistical stepwise analysis of dCMAP and MNCV revealed more severe neuropathy in the lower extremities in both diseases and damage to the peroneal nerve was most severe. Proximal/distal CMAP amplitude ratio analysis revealed CIDP to have a significantly lower amplitude than CMT1. Correlation analysis and Fisher’s Z test conducted with MNCV showed that CIDP exhibited conduction block and asymmetric nerve damage patterns. Some other atypical variants have been reported, highlighting the need for further research from various perspectives.