Functional magnetic resonance imaging (fMRI) paradigms, such as the immediate/delayed memory task (I/DMT), detect cognitive impairment in multiple sclerosis (MS) patients. Preliminary findings using I/DMT showed differences in blood oxygenation level dependent (BOLD) activation between cognitively impaired MS patients and non-impaired MS patients. A recent study sought to confirm cognitive impairment based on I/DMT BOLD activation in a cohort of 50 MS patients while examining the role of T2 lesion volume and Expanded Disability Status Scale (EDSS) in magnitude of BOLD signal. Researchers found:

• Analysis of variance showed non-impaired patients had significantly greater working memory activation than impaired patients, in the left prefrontal cortex and left supplementary motor area.
• Regression analysis showed significant inverse correlations between working memory activation and T2 lesion volume/EDSS in similar areas.