The study aims to characterize the relationship between cognitive function and regional brain volume in multiple sclerosis (MS) patients.

MS patients commonly report cognitive symptoms such as losing their train of thought or forgetting why they entered a room. However, working memory maintenance in MS – which may underlie these symptoms – is under-investigated and impairment is not always captured through formal neurocognitive testing. Thalamic atrophy, an early disease marker, correlates with cognitive impairment, but patterns of volume change in brain regions subserving working memory and executive function have not been well established.

Using the RADIEMS cohort of clinic patients at a tertiary care center, we examined correlations between cognitive domains and T1 brain volume in bilateral caudate, putamen, and thalamus. Cognition was represented by latent factors for working memory and executive function/speed derived from patients’ self-report on the Perceived Deficits Questionnaire. All results included covariates for age and sex and were FDR-corrected for multiple comparisons.

We examined a sample of 116 patients (78 females, 38 males; mean age 40.8 years (SD 7.9); mean EDSS 1.2 (SD 1.3)). Worsened subjective reports of working memory was associated with lower volume in bilateral thalamus and putamen (p<0.049). Executive/processing speed was associated with lower volumes in bilateral thalamus, caudate, and putamen (p<0.038).

We found that lower brain volume in regions subserving working memory and executive function may be a biomarker of worsened daily cognitive functioning in patients, as well as a proxy for disease-related neurodegeneration.