Quantifying dexterity and grip strength associations between age, cognitive function (MoCA), and cerebellar gray matter volume in healthy adults across the adult lifespan
Year: 2026
Type: article
Abstract: Cerebellar Crus I/II gray matter volume (GMV) is a structural marker of cognitive aging, and motor performance predicts age-related cognitive decline. Whether grip strength and manual dexterity dissociate in their cerebellar and cognitive correlates is unknown. We computed Pearson partial correlations (age, sex, and race covaried) between grip strength, Nine-Hole Peg Test (9HPT) dexterity, cerebellar Crus I/II GMV, and Montreal Cognitive Assessment (MoCA) subscores in 304 healthy adults aged 20–79 from the University of South Carolina Aging Brain Cohort. GMV was derived from T1-weighted MRI using CAT12 with the AAL3 atlas. After false discovery rate (FDR) correction, dominant 9HPT time correlated with MoCA total score ( r =-.240) and memory index ( r =-.220; both pFDR<0.001). Grip strength was unrelated to any MoCA measure but correlated bilaterally with Crus II GMV ( r =.156–.224, all pFDR≤0.041). Bootstrapped mediation indicated that dexterity statistically accounted for 28.8% of the age–cognition association and Crus II volume for 34.4–41.4% of the age–grip association. Dichotomizing at the MoCA cut-off of 26, each additional second of peg time carried 17.6% higher odds of scoring below cut-off (odds ratio = 1.176, 95% CI [1.062,1.302]) while grip strength carried none. Grip strength, but not dexterity, was independently associated with Crus II GMV, whereas dexterity, but not grip, was associated with cognition. Grip strength and dexterity are therefore not interchangeable indices of motor function. Because the design is cross-sectional, mediation estimates describe shared variance rather than causal pathways, and the pronounced MoCA ceiling likely attenuated the cognitive associations.
Source: Brain Structure and Function
Institution: University of South Carolina
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $4,790
OpenAlex ID: W7223170657