The distinct movement disorder in anti-NMDA receptor encephalitis may be related to Status Dissociatus: a hypothesis

The majority of patients with anti-N-methyl-D-aspartate-receptor encephalitis (NMDAE) present a characteristic movement disorder, which consists of complex bilateral stereotyped movements of the arms, with perioral and eye movements, and less frequently involvement of the legs. We have observed striking similarities in the characteristics of the abnormal movements observed in NMDAE and those described in Status Dissociatus, which is characterized by a complete breakdown of state-determining boundaries (wakefulness, REM and NREM sleep) and can result from pathophysiologically diverse disorders (e.g. fatal familial insomnia, delirium tremens, Morvan's syndrome). Here, we suggest that the state of paradoxical responsiveness in which NMDAE patients present these stereotyped movements may be that of Status Dissociatus and discuss the clinical similarities and pathophysiological explanations that support such a suggestion. This hypothesis explains why patients that seem to be unconscious have a movement disorder that is not epileptic and may have management implications, since many patients with NMDAE-related movement disorder are treated with anticonvulsants that may not be indicated.