We believe that our present understanding of these syndromes is insufficient to separate CIDP from MMN clearly and consider MMN to be a remarkably multifocal, predominantly motor variant of CIDP with the very unusual electrophysiologic feature of conduction block confined to motor axons. Further studies are clearly needed to clarify fully the relationship between CIDP and MMN and the relationship of MMN and other motor syndromes to various ganglioside antibodies.