FLAIR lesion volume in multiple sclerosis: relation to processing speed and verbal memory.

Information processing speed and episodic memory are two commonly affected cognitive abilities in MS. Insights into the mechanisms of and relationships between these abilities have recently come from structural neuroimaging techniques, but few studies have used fluid-attenuated inversion recovery (FLAIR), a neuroimaging sequence known to be sensitive to cortical and juxtacortical lesions in MS. We hypothesized that a volumetric index of FLAIR total lesion volume (TLV) would be associated with slowed processing speed and verbal memory dysfunction in MS. Twenty MS patients underwent FLAIR imaging and were administered measures of verbal memory and processing speed. Correlational and regression analyses indicated that TLV was directly and independently related to measures of processing speed and verbal memory, and TLV accounted for 56% of the variance in cognitive performance. These findings, considered in the context of prior work, suggest that FLAIR TLV is a useful predictor of commonly impaired cognitive functions in MS, and shows promise as a functionally relevant biomarker for disease status.