Understanding whether multiple sclerosis (MS) can have a favorable course is still challenging. However, a small group of patients who are not disabled after many years of disease can be identified. The mechanisms responsible for this ‘benign’ clinical course remain unclear, likely due to the lack of long-term studies.
To assess brain damage in multiple sclerosis patients with no or minimal disability after a longstanding clinical course.
We compared 13 patients with long-term benign clinical course (LT-BMS, age >55 years, disease duration >30 years, Expanded Disability Status Scale [EDSS] <3.0) and 27 non-benign MS (non-BMS) patients (age >55 years, EDSS >3.0). MRI scans were retrospectively assessed (mean follow-up: 11 years, mean scan per patient: 3). Comparisons of brain volumes (BV) and total T2-lesion volume (LV) changes between the two groups were performed using a mixed effect model. Lesion probability maps (LPMs) of both groups were compared using a nonparametric permutation test.
Patients with LT-BMS showed less over-time decrease in global BV (p=0.02) and grey matter (GM) volume (p<0.001) than non-BMS. Lower atrophy was seen in LT-BMS with no or mild cognitive impairment. By contrast, there was no over-time difference between patient groups in T2-LV accumulation and lesion frequency across brain.
Global brain and GM atrophy changes were mild in this unique patient group with long-standing and no or minimal physical and cognitive disability. These results support the relevant role of GM atrophy in characterizing MS patients who may have favorable long-term disease evolution.