Immunotherapy of oneiric stupor in Morvan syndrome: Efficacy documented by actigraphy

Morvan syndrome (MoS) is a rare acquired channelopathy associated with autoantibodies against potassium channel complex and clinically characterized by the heterogeneous combination of neuromyotonia, dysautonomia, and encephalopathy.¹ Peculiar CNS symptoms are organic insomnia, which ranges from mild to malignant forms characterized by complete loss of sleep, and persistent motor/autonomic hyperactivation (agrypnia excitata²). We describe a patient with MoS who developed progressive agrypnia excitata, in which IV immunoglobulin (IVIg) treatment induced a progressive recovery of the physiologic sleep-wake cycle, documented by videopolysomnography (VPSG) and actigraphic monitoring.