Longitudinal associations between MRI and cognitive changes in very early MS.

Objectives: Cognitive dysfunction in multiple sclerosis (MS) has been primarily examined in patients with advanced disease. Our objective was to study the longitudinal associations between brain magnetic resonance imaging (MRI) metrics and neuropsychological outcomes in patients with early MS.

Methods: Relapsing MS patients within 12 months of onset were enrolled in a neuroprotection trial of riluzole versus placebo with up to 36 months of follow-up. MRI metrics included percent brain volume changes measured by SIENAX normalized measurements [normalized brain parenchymal volume (nBPV), normalized normal-appearing white and gray matter volume (nNAWMV and nGMV)] and T2 lesion volume (T2LV). A neuropsychological battery was performed annually. Mixed model regression measured time trends and associations between imaging and neuropsychological outcomes, adjusting for sex, age and education level.

Results: Forty-three patients (mean age 36 years; 31 females) were enrolled within 7.5 ± 4.9 months of disease onset. 11.6% of patients with baseline cognitive assessment met conservative criteria for cognitive impairment. Compared to placebo, riluzole had no significant effect on neuropsychological performance; thus, both groups were combined for the association analyses. Baseline T2LV predicted subsequent changes in PASAT (p=0.006) and SDMT (p=0.002) scores. Longitudinal changes of T2LV were associated with changes in CVLT-II (p<0.001).

Conclusion: These findings suggest that cognitive impairment is relatively common in patients with very early MS. Baseline and longitudinal changes in the lesion load may be associated with some of the most frequently identified changes in cognitive function in MS.