Tactile sensation moderates the association between hand dexterity and higher-level cognition in older adults with...

Tactile sensation and hand dexterity decline with age and are associated with later-life cognition, yet it remains unclear whether tactile sensation moderates the strength of hand motor-cognitive associations. This cross-sectional study examines whether tactile sensation moderates the association between hand dexterity and higher-level cognition (executive function and processing speed) in cognitively normal (CN) older adults and those with mild cognitive impairment (MCI), and whether moderation patterns differ between these groups.

Participants were 132 community-dwelling older adults aged ≥ 60 (female = 79; mean age = 73.3 ± 5.2). MCI was defined by MMSE ≥ 24 and MoCA ≤ 25. Executive function was assessed with Trail Making Test-B (TMT-B) and letter fluency (LFT); processing speed with TMT-A, Digit Symbol, and category fluency (CFT). Hand dexterity and tactile sensation were measured using the Purdue Pegboard Test and Weinstein-Semmes monofilaments. Moderation analyses tested the interaction between dexterity and tactile sensation, adjusting for demographic and health-related covariates.

Tactile sensation significantly moderated the association between hand dexterity and executive function and processing speed, with stronger dexterity-cognition associations among older adults with intact tactile sensation (TMT-B p < 0.05; LFT p < 0.05; TMT-A p < 0.01). No moderation was observed for Digit Symbol or CFT. The three-way interaction with cognitive group was not significant, indicating comparable patterns across groups. Stratified analyses showed a significant LFT interaction in the CN group (p < 0.05).

Older adults with intact tactile sensation showed stronger hand dexterity-cognitive associations, highlighting sensorimotor integrity as relevant for early screening and functional evaluation. Stratified patterns suggest possible cognitive group differences that merit further study.