Table 2.

Clinical Characteristics for DN-NMOSD

Attack type	Number of DN-NMOSD affected, N (%)	Number of attacks per affected person with DN-NMOSD, median (IQR)
Myelitis	21 (84)	4 (4–8)
Optic neuritis	17 (68)	2 (1–3)
Bilateral ON (consecutive or simultaneous)	6 (24)	2 (1–3.75)
Simultaneous bilateral ON	4 (16)	1 (1–1)
Brainstem syndromes	11 (44)	1 (1–1)
Area postrema syndrome	3 (12)	1 (1–1)

Abbreviations: DN-NMOSD = people with double-antibody seronegative neuromyelitis optica spectrum disorder; IQR = interquartile range; N = number.