Associations of Upper-Extremity Exercise Capacity and Grip Strength With Cognitive Domains in Patients With COPD

BACKGROUND: Cognitive impairment (CI), which has been reported in COPD, has been related to physical performance. However, the association between CI and upper-extremity functions is unknown. We aimed to compare upper-extremity exercise capacity and grip strength between subjects with COPD with and without CI and to determine the relationship of upper-extremity functions with specific cognitive domains. METHODS: In this cross-sectional study, 76 subjects with COPD (mean age 66.8 +/- 7.5 y, FEV 1 % 47.12 +/- 14.10) were classified as with and without CI according to the Montreal Cognitive Assessment. Clinical characteristics, upper-extremity exercise capacity (6-min pegboard ring test [6PBRT]), grip strength (hand dynamometer), dyspnea severity (modified Medical Research Council dyspnea scale), disease-specific health status (COPD Assessment Test), and disease-specific quality of life (St George Respiratory Questionnaire) were compared between groups, and the relationship of upper-extremity functions with cognitive subdomains was analyzed by multivariate regression analysis. RESULTS: The number of 6PBRT rings ( P = .01) and the grip strength ( P = .033) were lower in subjects with CI. Subjects with CI had lower FEV 1 % ( P = .038), arterial oxygenation ( P = .002), exercise habits ( P = .033), health status ( P = .01), quality of life ( P = .042); and higher dyspnea ( P < .001), smoking consumption ( P = .032), emergency admission ( P = .02), and hospitalization ( P = .042). The adjusted model showed that executive functions and attention were related to upper-extremity capacity ( fi = 14.4 and fi = 10.2, respectively) and hand-grip strength ( fi = 1.85 and fi = 1.49, respectively). CONCLUSIONS: These findings suggest that upper-extremity functions might be decreased especially concerning executive functions and attention in subjects with COPD with CI.