Thalamic Nuclei Volumes and Their Relationships to Neuroperformance in Multiple Sclerosis: A Cross-Sectional StructuralMRIStudy

Background Although reduced thalamic volume is associated with multiple sclerosis (MS)-related clinical impairment, the role of individual thalamic nuclei remains poorly understood. Purpose/Hypothesis To test whether individual thalamic nuclei volumes are more strongly associated with clinical disability than the whole thalamic volume. Study Type Retrospective analysis of a prospective dataset. Subjects A total of 108 MS patients and 48 age- and sex-matched healthy controls (HCs) Field Strength 3T. Sequences 3D T-1-weighted inversion recovery spoiled gradient echo; 2D T-2-weighted fluid-attenuated inversion recovery spin echo; 2D dual-echo proton density-weighted/T-2-weighted spin echo. Assessments Clinical assessments included the Expanded Disability Status Scale (EDSS), Nine-Hole Peg Test (9HPT), Timed 25-Foot Walk (T25FW), Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMTR), and the California Verbal Learning Test (CVLT2). FreeSurfer provided anterior, intralaminar, lateral, medial, ventral, posterior, and total volumes. Statistical Tests False discovery rate-corrected partial correlations (controlling for age, sex, and education) to assess the relationships between volumes and neuroperformance. Results Compared to HCs, MS patients presented with lower thalamic nuclei volumes (P < 0.05) except for the intralaminar nucleus (P= 0.279) and scored worse on all neuroperformance scales (P <= 0.05) except for CVLT2 (P= 0.151). All nuclei except intralaminar were associated with EDSS (correlation coefficient range: -0.233 to -0.395), SDMT (range: 0.247-0.423), and 9HPT (range: -0.232 to -0.303) (allP < 0.05). BVMTR was associated with anterior (r =0.319), lateral (r =0.31), and medial (r =0.304) volumes (allP < 0.05). T25FW correlated with ventral (r =-0.392) and total (r =-0.309) volumes (bothP < 0.05), with the latter being significantly greater (P < 0.05). Data Conclusion Assessing individual nuclei volume can aid in unraveling the relationship between thalamic pathology and disparate aspects of MS-related disability. Level of Evidence 2 Technical Efficacy Stage 2

Automated summary

The study found that compared to healthy controls, multiple sclerosis patients had smaller thalamic nuclei volumes and worse neuroperformance assessments. The various thalamic nuclei showed different levels of correlation with clinical disability, and assessing individual thalamic nuclei volumes can help understand the relationship between thalamic pathology and MS-related disability.