Multiple sclerosis in Hokkaido, the northernmost island of Japan: prospective analyses of clinical features.

We analyzed the clinical features of multiple sclerosis (MS) prospectively seen between July 1986 and October 1989 on Hokkaido island, the northernmost part of Japan. Clinical features were generally considered to be intermediate between the previous Japanese reports and those of Western countries. Devic's disease was rare and simultaneous bilateral visual loss at on set was not too common this series, differing from that previously reported of Japanese MS. The high incidence of acute transverse myelopathy and lesser involvement of the cerebellum, however, support the previous view. Further clinical and epidemiological studies will be necessary on this island.