Objectives: To assess the role of the cardiac autonomic nervous system (ANS), as measured according to spontaneous cardiac baroreflex sensitivity (BRS), in the type and degree of cognitive performance in healthy young-elderly individuals, taking into account the presence of other vascular risk factors.
Design: Community-based cross-sectional study.
Setting: In-home and clinical settings.
Participants: A subset of participants, aged 66.9±0.9, from a prospective study that aimed to assess the influence of ANS activity on cardiovascular and cerebrovascular morbidity and mortality (N=916).
Measurements: All subjects underwent a clinical interview, neuropsychological testing, and autonomic and vascular measurements. Three cognitive domains were defined: attentional (Trail-Making Test Part A, Stroop code and parts I & II), executive (Trail-Making Test Part B, Stroop part III, verbal fluency and similarity tests), and memory (Benton visual retention test, Grober and Buschké procedure). Subjects were stratified according to their scores into normal, low, and impaired performers.
Results: After adjustments to demographic and vascular data, participants with moderate autonomic dysregulation (3<BRS≤6) were determined to be 1.82 times as likely to have memory impairment (odds ratio (OR)=1.82, 95% confidence interval (CI)=1.13-3.17, P=.02) and those with severe autonomic dysregulation (BRS≤3) to be 2.65 as likely (OR=2.65, 95% CI=1.40-5.59, P=.006) as participants with normal BRS (>6).
Conclusion: In older individuals without dementia, autonomic dysregulation seems to have a direct, gradual, and independent effect on memory. Future studies are needed to evaluate the long-term effects of BRS and other markers of the ANS on cognitive decline.
Trial registration: ClinicalTrials.gov NCT00759304 NCT00766584.
Keywords: autonomic nervous system; baroreflex sensitivity; cognitive functions; healthy elderly; vascular risk factors.
© 2013, Copyright the Authors Journal compilation © 2013, The American Geriatrics Society.