AQP4 and optic neuritis: Notably, EDSS at nadir (peak disability during acute attacks) was higher in AQP4-IgG NMOSD patients (median 6, IQR 4–8) than in MOGAD patients (median 5, IQR 3–7), suggesting more severe acute attacks in NMOSD, although some MOGAD patients also experienced high nadir disability (e.g., during severe optic neuritis or myelitis (Table 1) Attack Treatment.