Walsh & Hoyt: Laboratory Findings

Electrophysiologic studies in patients with CIDP typically show marked slowing of motor conduction with prolonged distal latencies in at least two limbs. Some patients show a multifocal conduction block. F-wave responses are abnormal 95% of the time. In a series of eight consecutive patients, visual evoked responses were abnormal in six, BAEPs were abnormal in two, and MR imaging showed changes consistent with CNS demyelination in two cases. These laboratory findings suggest that CIDP, like AIDP and MFS, may rarely present as a combined central and peripheral demyelinating syndrome.