Age-Varying Relationships Between Physical Function and Cognition in Older Adulthood

Area of Science:

• Gerontology
• Cognitive Neuroscience
• Biomedical Gerontology

Background:

• Positive associations exist between physical and cognitive function in older adults.
• Inconsistencies in the strength of these relationships across studies highlight a need for advanced analytical methods.
• Novel statistical approaches have not been widely applied in gerontological research to explore these variations.

Purpose of the Study:

• To investigate age-related differences in the magnitude of relationships between physical function and cognitive performance in healthy older adults.
• To apply time-varying effects modeling (TVEM) to gerontological research for the first time.
• To examine how physical function metrics (Turn 360, grip strength) predict cognitive domains (memory, processing speed/attention, reasoning) across different age strata.

Main Methods:

• Employed time-varying effects modeling (TVEM), a regression extension, to analyze relationships.
• Utilized data from 2,783 healthy older adults aged 65-90.
• Assessed physical function via Turn 360 test and grip strength.
• Evaluated cognitive performance across memory, processing speed/attention, and reasoning domains.

Main Results:

• All associations between Turn 360 and cognitive domains were significant and positive.
• Processing speed showed significant age-related magnitude variation, with strongest links in the young-old and old-old.
• Grip strength associations with all cognitive domains significantly strengthened as participants aged.

Conclusions:

• The strength of physical-cognitive relationships in older adults is age-dependent, potentially explaining prior study inconsistencies.
• Future longitudinal research is recommended to further clarify these dynamic associations.
• TVEM offers a valuable tool for exploring age-varying relationships in gerontology.