The Dynamic Relationship Between Physical Function and Cognition in Longitudinal Aging Cohorts

Abstract

On average, older people remember less and walk more slowly than do younger persons. Some researchers argue that this is due in part to a common biologic process underlying age-related declines in both physical and cognitive functioning. Only recently have longitudinal data become available for analyzing this claim. We conducted a systematic review of English-language research published between 2000 and 2011 to evaluate the relations between rates of change in physical and cognitive functioning in older cohorts. Physical functioning was assessed using objective measures: walking speed, grip strength, chair rise time, flamingo stand time, and summary measures of physical functioning. Cognition was measured using mental state examinations, fluid cognition, and diagnosis of impairment. Results depended on measurement type: Change in grip strength was more strongly correlated with mental state, while change in walking speed was more strongly correlated with change in fluid cognition. Examining physical and cognitive functioning can help clinicians and researchers to better identify individuals and groups that are aging differently and at different rates. In future research, investigators should consider the importance of identifying different patterns and rates of decline, examine relations between more diverse types of measures, and analyze the order in which age-related declines occur.

Social Isolation, Loneliness, and Health Behaviors at Older Ages: Longitudinal Cohort Study

“…Their respective relationships with the long-term persistence of health-related behaviors over time are less well understood, particularly in the context of aging. Older age is a time period in life when maintaining healthy lifestyle behaviors can become particularly challenging due to changing life circumstances including increasing risks of physical and cognitive impairments [23]. At the same time, healthy behaviors become increasingly important in later life for the maintenance of quality of life and well-being [24].…”

Motor function in the elderly

“…A recent review reported standardized b regression coefficients comprised between 0.05 and 0.15 34 ; the authors concluded that the observed associations were not sufficiently strong or consistent to provide conclusive evidence for common causes. 34 Cognition appears not to have a major role in the education-WS association: in our study, MMSE explained 15% of the association; using alternative tests (Isaac Test, Benton Visual Retention Test, Trail Making Test) yielded similar conclusions (data not shown). Finally, because childhood and adult SES are independently associated with slower WS in old age, 35 parental education was used as a surrogate for childhood SES and attenuated the education-WS association by approximately 12%.…”

Grip strength and healthy aging

“…In their systematic review, Clouston et al 33) reported finding an association between grip strength and cognitive function, with grip strength predicting the development of Alzheimer's disease 34) . However, they concluded that the associations between grip strength and cognitive function were not sufficiently strong to provide conclusive evidence for "common cause" aging.…”