Diagnosis of multifocal motor neuropathy

Abstract

We read with great interest Van Asseldonk and colleagues' review of the clinical features, diagnostic criteria, pathophysiology, and treatment of multifocal motor neuropathy (MMN).1 The authors highlight that MMN is an immune-mediated disease in which the clinical picture mimics that of lower-motor-neuron disease (LMND). However, two very important features differ in these disorders: the neurophysiological picture and the responsiveness to treatment with intravenous immunoglobulin. Patients with MMN typically have conduction block in motor nerves, whereas those with LMND do not;2 hence, conduction block is key in the differential diagnosis.