Duration of the distal compound muscle action potential for diagnosis of chronic inflammatory demyelinating polyneuropathy: effects of low-cut filters.

Purpose: In current electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy, the cutoff values of distal compound muscle action potential (DCMAP) duration are defined using electromyogram low-cut filter setting of 20 Hz. We aimed to assess effects of low-cut filter on DCMAP duration (10 vs. 20 Hz).