Table 4.

Time and number of attacks until the diagnosis of NMO was made by the treating physicians.

	Time (median, range, N)	p-level
All patients	37.5 months (0-390; 112)
ON at onset MY at onset	55 months (0-390; 66) 16 months (0-255; 29)	P < 0.013§
Isolated ON or MY at onset Simultaneous ON + MY at onset	49 months (0-390; 94) 1 month (0-18; 13)	P < 0.000001§
Seropositives Seronegatives	45 months (0-390; 88) 11 months (0-255; 24)	P < 0.029§
	Number of attacks (median, range, N)
ON attacks MY attacks	1.0 (1-8; 118) 1.0 (1-5; 109)	n.s.§

^§Mann Whitney U test. MY = myelitis; N = number of patients (not all data were available from all patients); n.s. = not significant; ON = optic neuritis.