Area postrema syndrome: Frequency, criteria, and severity in AQP4-IgG-positive NMOSD

OBJECTIVE: To define the frequency, duration, and severity of intractable nausea, vomiting, or hiccups in aquaporin-4-immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD) and propose diagnostic criteria and a severity scale for area postrema syndrome (APS). METHODS: An International NMOSD database was interrogated for frequency of APS. Patients with AQP4-IgG-positive NMOSD completed an APS symptom questionnaire. …