Ultrasonographic, Electrophysiological and Clinical Profiles of Motor and Motor Predominant Chronic Inflammatory Demyelinating Polyneuropathy

INTRODUCTION/AIMS: The distinct ultrasonographic and electrophysiological features separating typical chronic inflammatory demyelinating polyneuropathy (CIDP) from its motor-predominant and pure motor variants remain poorly defined. We aimed to characterize the ultrasonographic, electrophysiological, and clinical features of these CIDP subtypes within a Chinese cohort. METHODS: Between March 2015 and January 2025, we prospectively enrolled consecutive patients meeting the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) diagnostic criteria for CIDP. All participants underwent standardized nerve ultrasound and nerve conduction studies (NCS). RESULTS: A total of 206 CIDP patients were recruited, including 145 with typical CIDP, 10 with motor-predominant CIDP, and 8 with motor CIDP. Significant nerve enlargement was present in 34 (23.4%) of typical, one (10%) of motor-predominant, and none of motor CIDP patients. Cross-sectional areas (CSAs) at most upper limb nerve sites were significantly larger in motor-predominant than in motor CIDP. Electrophysiologically, motor nerve conduction velocities (MCVs) of upper limb nerves were slower in motor-predominant CIDP than in motor CIDP, and were also slower in distal segments in typical CIDP compared to motor-predominant CIDP. Corticosteroid responsiveness demonstrated a clear declining trend across the subtypes: 93.8% (106/113) in typical, 85.7% (6/7) in motor-predominant, and 50% (3/6) in motor CIDP. DISCUSSION: Our findings support the concept of a disease spectrum from typical to motor CIDP, characterized by progressively decreasing nerve CSA enlargement on ultrasound, less prominent demyelinating features on NCS, and a diminished therapeutic response to corticosteroids.