Relationship between Barkhof criteria and the clinical features of multiple sclerosis in northern Japan.

We previously reported that the prevalence of multiple sclerosis (MS) in the Tokachi Province of Hokkaido increased from 8.6 to 13.1 per 100,000 individuals between 2001 and 2006. Here, we study the frequency of MS patients who fulfill the Barkhof criteria and identified their common features. All 47 subjects in our previous study, who fulfilled Poser's criteria, were included in this study. Of these, 33 satisfied the Barkhof criteria. In 2006, 9.2 per 100,000 MS patients fulfilled the Barkhof criteria; the percentage of patients who fulfilled these criteria was significantly higher among patients born after 1960 than among those born before 1960 (84.3% and 40.0%, respectively). The proportion of patients with conventional MS (C-MS) who fulfilled the Barkhof criteria was higher than that of patients with opticospinal MS (OS-MS) who fulfilled these criteria (93.9% and 71.4%, respectively). Longitudinally extensive spinal cord lesions (LESCLs) were not associated with the brain lesions defined in the Barkhof criteria (Barkhof brain lesions). In Tokachi Province, the increased percentage of MS patients who fulfill the Barkhof criteria was associated with increased C-MS incidence and an increase in the proportion of C-MS patients with Barkhof brain lesions among people born after 1960.