To review the utility of inpatient movement neurophysiology study (MNS) in the characterization and management of severe, refractory dyskinesias in a case of anti-NMDA receptor encephalitis (NMDARE).

Our patient is a 35-year-old woman who presented after one week of personality changes, insomnia, hallucinations, abnormal movements, and seizure. Testing with CSF, EEG, serum and CT/MRI was consistent with NMDARE with bilateral ovarian teratomas. Initial exam revealed an intubated, obtunded patient, with frequent facial and extremity movements. Initial therapy included bilateral oophorectomy, aggressive early immunotherapy, and sedation for dysautonomia and dyskinesias. Severe dyskinesias continued resulting in ventilator dyssynchrony necessitating use of combined vesicular monoamine transporter 2 inhibitors (VMAT2), high-dose sedatives, anesthetics, and muscle-relaxants.  MNS was conducted which defined movements as motor stereotypies without evidence of dystonia which could have been amenable to deep brain stimulation. As a result of the MNS, aggressive immunotherapy was continued with rituximab, intravenous immunoglobulins (IVIG), and high-dose steroids. MNS 8 months later revealed interval worsening, with 22 out of 26.5 hours (83%) with continuous movements. This led to discontinuation of steroids and optimization of additional symptomatic treatments including long-acting VMAT2 inhibitors and cannabinoids, which allowed for weaning of sedation. Follow up MNS 3 months later showed improvement with 7 out of 49 hours (14%) with continuous movements.

Inpatient MNS are useful for patients with NMDARE to classify phenomenology and provide objective assessment of severity of movement disorders in which there are therapeutic implications.