Disability and T2 MRI lesions: a 20-year follow-up of patients with relapse onset of multiple sclerosis

Clinically isolated syndromes (CIS), such as optic neuritis, brainstemor spinal cord syndromes are frequently the first clinical presentations of multiple sclerosis. However, not all CIS patients develop multiple sclerosis and in those who do, disability is highly variable. In previous follow-up studies, brain lesions onT2-weighted MRI are associated with increased risk of multiple sclerosis and to an extent disability.We evaluated the longitudinal rela-tionships between the MRI lesions and clinical course over a period of 20 years. CIS patients were recruited between1984 and1987 and previously followed up after 1, 5, 10 and14 years.Of the 140 subjects whowere initially recruited with a CIS for a baseline MRI study, we followed up 107 patients after a mean of 20.2 years (range 18^27.7). Multiple sclerosis was diagnosed as clinically definite on clinical grounds only and disability determined using the Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Functional Composite (MSFC) score. Clinically definite multiple sclerosis developed in 67 out of 107 (63%) overall: 60 out of 73 (82%) with abnormal and 7 out of 34 (21%) with normal baseline MRI. Multiple sclerosis was still relapsing-remitting in 39 (58%)çincluding 26 (39%) with a ‘benign’course (EDSS · 3)çwhilst 28 (42%) had developed secondary progres-sion. T2 lesion volume at all time-points correlated moderately with 20-year EDSS (rs values 0.48 to 0.67; P _ 0.001) and MSFC z-score [rs values (^0.50) to (^0.61); P _ 0.001]. In those developing multiple sclerosis, a con-current correlation of change inT2 lesion volume with change in EDSS was most evident in years 0^5 (rs = 0.69