Association of adjustability of grasping force in dominant and nondominant hands with physical and cognitive function in community-dwelling older adults: a cross-sectional study

Abstract Background Adjustability of grasping force (AGF) is essential for activities of daily living (ADL) and instrumental ADL. However, its association with physical and cognitive functions in older adults, and whether these associations differ by hand remain unclear. Therefore, we investigated these associations using a visual tracking task. Methods This cross-sectional study included 129 community-dwelling older adults from Kagamiishi Town. AGF was assessed as the error between target and measured forces (grasping error) in dominant and nondominant hands. Physical function measures included grip strength, pulp and key pinch strengths, and Purdue Pegboard Test (PPT) score. Cognitive function was assessed using the Japanese version of the Montreal Cognitive Assessment (MoCA-J). We used age- and sex-adjusted generalized linear models for the dominant and nondominant hands. Functional indicators included the MoCA-J visuospatial/executive subscore. Results A total of 129 participants (mean age: 76.2 ± 4.69 years; 69.0% female) were analyzed. Grasping errors did not differ between hands (dominant hand: 0.13 ± 0.09 N, nondominant hand: 0.12 ± 0.07 N; p = 0.113). In the dominant hand, only the MoCA-J visuospatial/executive subscore was significantly associated with grasping error (β = -0.156, p = 0.008). In the nondominant hand, both MoCA-J visuospatial/executive subscore (β = -0.102, p = 0.036) and PPT score (β = -0.057, p = 0.014) were significantly associated with grasping error. Conclusion Visuospatial/executive function was associated with AGF in both hands. Dexterity was additionally associated with AGF in the nondominant hand. These findings may inform hand-specific assessment or intervention strategies for older adults.