Objectives: To examine whether changes in the cardiac autonomic nervous system (ANS) over time, as expressed by baroreflex sensitivity (BRS), were associated with long-term changes in cognitive performance in elderly individuals without dementia.
Design: Community-based 8-year longitudinal study.
Setting: Clinical settings.
Participants: Individuals aged 66.9 ± 0.9 (N = 425).
Measurements: At baseline and follow-up, subjects underwent a clinical interview, autonomic and vascular measurements, and a neuropsychological evaluation including attentional, executive, and memory tests using standardized Z-scores. BRS was defined as being normal, moderate, or severe alteration at each evaluation. On the basis of the longitudinal changes subjects were stratified as being stable, moderate or improved.
Results: Mean attentional, executive, and memory change Z-scores were -0.41 ± 0.9, -0.15 ± 0.7, and -0.14 ± 0.8, respectively. BRS of 56% of the subjects remained unchanged, of 20% decreased, and of 24% improved. After regression analysis, the worsened BRS group was 1.88 times as likely to have greater memory change as the group with stable BRS (P = .02). No significant association was found between longitudinal change in BRS and attentional and executive changes.
Conclusion: In healthy elderly individuals, BRS decrease was associated with a weak but significant decrease in memory function. The long-term effect of BRS on memory changes may suggest a role of the ANS in cognitive decline.
Trial registration: ClinicalTrials.gov NCT00759304 NCT00766584.
Keywords: autonomic nervous system; baroreflex sensitivity; cognitive functions; healthy elderly; longitudinal changes.
© 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.