O2-6-21. Comparison of muscle ultrasound findings between demyelinating neuropathy and axonopathy

Denervation causes increased echo intensity (EI) and decreased muscle thickness (MT) on muscle ultrasound (MUS). Chronic inflammatory demyelinating polyneuropathy (CIDP) does not present with denervation unless secondary axonal degeneration occurs. Hence, few MUS changes would occur compared to amyotrophic lateral sclerosis (ALS). The abductor pollicis brevis, abductor digiti minimi, and first dorsal interosseous muscles of 12 patients with CIDP and 13 patients with ALS were examined. There were no significant differences in Medical Research Council scales of each muscle between the CIDP and ALS group. EI and MT were measured quantitatively in every muscle. Raw values were converted into z-scores using the data from 40 normal controls (NCs). There were no significant differences between the CIDP and NC groups regarding EI and MT. The ALS group exhibited significantly higher EI and significantly lower MT than the other two groups (all P