Desempenho da força muscular em idosos com doença de Alzheimer: um estudo transversal

Abstract

Background: Reduced muscle strength and loss of functional capacity are observed with aging. Studies have shown that additionally to the inherent cognitive decline, decreased strength, balance, and mobility are observed in Alzheimer's disease (AD). However, the understanding of muscle performance evaluated by an isokinetic machine in older adults with AD compared to Cognitively Preserved individuals is still scarce in the literature. Objective: To compare the lower limbs’ strength performance of older adults with AD and Cognitively Preserved individuals by analyzing the knee isometric and concentric torques during the extension and flexion movements. Methods: A cross-sectional study was conducted where a sample of 40 older adults was divided into two groups: AD (n = 20) and Cognitively Preserved (n = 20). The following parameters were collected: Knee isometric and concentric torques (60°/s and 180°/s), Time Up and Go, Alternate Step (8x), 5x and 30 seconds Sit-to-Stand test, Handgrip Strength, Modified Baecke Questionnaire for Older Adults, Addenbrooke's Cognitive Examination-Revised and Geriatric Depression Scale. For statistical analysis, the Shapiro-Wilk, Student t and ChiSquare tests were used and a 5% significance level was set a priori. Results: The AD group presented lower values in muscle performance (total work) for knee extension (p=0.02). No significant differences were found for isometric and concentric torques. The Alternate Step (p=0.02) and the Addenbrooke's Cognitive Examination-Revised (p=0.01) were significantly diferente, being the group of AD with worse performance. Conclusion: This study identified a decreased muscle performance (concentric at 180°/s) of the quadriceps muscles during the knee extension movement in older adults with AD.