Handgrip Strength Asymmetry and Gait Speed Interact to Predict Cognitive Status in Adults Aged 70 and Older

Background: Handgrip strength (HGS) and usual pace gait speed are inexpensive biomarkers of biological aging that predict disability, frailty, and mortality. Although each trait correlates with cognition, the combined contribution of handgrip asymmetry and gait speed to cognitive status in later life remains under explored, especially in adults ≥70 years, the age at which motor cognitive coupling accelerates. Methods: We analyzed baseline data from 523 community dwelling adults (82.3 ± 9.8 y, 70 % women) enrolled in the Banner Longevity Study. Maximal HGS of each hand was measured with a Jamar dynamometer; usual pace gait speed was calculated over a 3.05 m walkway (10 ft) and expressed in m·s⁻¹. Handgrip strength asymmetry (HGSA) was defined as an absolute inter hand ratio < 0.90 or > 1.10; values between 0.90–1.10 denoted symmetry. Participants were categorized as slow (< 0.76 m·s⁻¹, sex specific 50th percentile) or normal walkers. Global cognition (Mini Mental State Examination, MMSE) and informant rated everyday cognition (ECog) were assessed. Two way ANCOVA (HGSA × gait speed category) and sex stratified linear regressions examined associations, controlling for age, education, body mass index, depressive symptoms (CES D ≥ 16 = high), and physical activity (RAPA).Results: HGSA was present in 55 % of participants. There was a significant HGSA × gait speed interaction on MMSE (F[1,310] = 12.09, p < 0.001, η² = 0.038). Slow walkers with HGSA scored lowest (27.3 ± 2.9) compared with symmetrical slow walkers (28.7 ± 2.2) and all normal speed groups (post hoc Bonferroni p's < 0.05). In regression models, gait speed predicted MMSE more strongly when asymmetry was present (R² = 0.15) than when absent (R² = 0.02). Each 0.15 m·s⁻¹ (≈0.5 ft·s⁻¹) faster gait was associated with a 1 point higher MMSE (β = 0.54, 95 % CI 0.35–0.73). Greater symmetry (smaller HGS ratio) related to worse ECog Memory (β = −0.27, p = 0.02) and ECog Language (β = −0.24, p = 0.04) scores.Conclusions: Loss of typical dominant hand strength advantage and slower gait are jointly associated with lower global and everyday cognitive performance in adults ≥70 yrs old. Including simple measures of HGS asymmetry and usual pace gait speed alongside cognitive screening may improve early identification of motor cognitive vulnerability in geriatric practice. Prospective studies are required to establish temporal sequencing.Keywords: handgrip strength asymmetry; gait speed; cognition; aging; motor cognitive coupling; MMSE