Aerobic exercise improves executive functions in females, but not males, without the BDNF Val66Met polymorphism

BACKGROUND

Aerobic exercise promotes cognitive function in older adults; however, variability exists in the degree of benefit. The brain-derived neurotropic factor (BDNF) Val66Met polymorphism and biological sex are biological factors that have been proposed as important modifiers of exercise efficacy. Therefore, we assessed whether the effect of aerobic exercise on executive functions was dependent on the BDNFval66met genotype and biological sex.

METHODS

We used data from a single-blind randomized controlled trial in older adults with subcortical ischemic vascular cognitive impairment (NCT01027858). Fifty-eight older adults were randomly assigned to either the 6 months, three times per week progressive aerobic training (AT) group or the usual care plus education control (CON) group. The secondary aim of the parent study included executive functions which were assessed with the Trail Making Test (B-A) and the Digit Symbol Substitution Test at baseline and trial completion at 6 months.

RESULTS

Analysis of covariance, controlling for baseline global cognition and baseline executive functions performance (Trail Making Test or Digit Symbol Substitution Test), tested the three-way interaction between experimental group (AT, CON), BDNFval66met genotype (Val/Val carrier, Met carrier), and biological sex (female, male). Significant three-way interactions were found for the Trail Making Test (F(1,48) = 4.412, p < 0.04) and Digit Symbol Substitution Test (F(1,47) = 10.833, p < 0.002). Posthoc analyses showed female Val/Val carriers benefited the most from 6 months of AT compared with CON for Trail Making Test and Digit Symbol Substitution Test performance. Compared with CON, AT did not improve Trail Making Test performance in male Val/Val carriers or Digit Symbol Substitution Test performance in female Met carriers.

CONCLUSIONS

These results suggest that future randomized controlled trials should take into consideration BDNF genotype and biological sex to better understand the beneficial effects of AT on cognitive function in vascular cognitive impairment to maximize the beneficial effects of exercise and help establish exercise as medicine for cognitive health.

Frontotemporal dementia and COVID-19: Hypothesis generation and roadmap for future research

The COVID-19 pandemic has caused tremendous suffering for patients with dementia and their caregivers. We conducted a survey to study the impact of the pandemic on patients with mild frontotemporal dementia (FTD). Our preliminary findings demonstrate that patients with FTD have significant worsening in behavior and social cognition, as well as suffer greater negative consequences from disruption to health-care services compared to patients with AD. The reduced ability to cope with sudden changes to social environments places patients with FTD at increased vulnerability to COVID-19 infection as well as to poorer clinical and social outcomes. Caregivers of FTD patients also demonstrate high burden during crisis situations. A proportion of patients with FTD benefitted from use of web-based interactive platforms. In this article, we outline the priority areas for research as well as a roadmap for future collaborative research to ensure greatest benefit for patients with FTD and their caregivers.