Hippocampal atrophy is associated with memory impairment and dementia and serves as a key biomarker in the preclinical stages of Alzheimer's disease. Physical activity, one of the most promising behavioral interventions to prevent or delay cognitive decline, has been shown to be associated with hippocampal volume; specifically increased aerobic activity and fitness may have a positive effect on the size of the hippocampus. The majority of older adults, however, are sedentary and have difficulty initiating and maintaining exercise programs. A modestly more active lifestyle may nonetheless be beneficial. This study explored whether greater objectively measured daily walking activity was associated with larger hippocampal volume. We additionally explored whether greater low-intensity walking activity, which may be related to leisure-time physical, functional, and social activities, was associated with larger hippocampal volume independent of exercise and higher-intensity walking activity. Segmentation of hippocampal volumes was performed using FMRIB's Software Library (FSL) and daily walking activity was assessed using a step activity monitor (SAM) on 92, non-demented, older adult participants. After controlling for age, education, body mass index (BMI), cardiovascular disease risk factors, and the Mini Mental State Exam (MMSE), we found that a greater amount, duration, and frequency of total daily walking activity were each associated with larger hippocampal volume among older women, but not men. These relationships were specific to hippocampal volume, compared to the thalamus, used as a control brain region, and remained significant for low-intensity walking activity, independent of moderate- to vigorous-intensity activity and self-reported exercise. This is the first study, to our knowledge, to explore the relationship between objectively measured daily walking activity and hippocampal volume in an older adult sample. Findings suggest the importance of better understanding whether increasing non-exercise, lifestyle physical activities may produce measurable cognitive benefits and effect hippocampal volume through molecular pathways unique to those related to moderate-intensity exercise.

Background There is substantial interest in identifying interventions that can protect and buffer older adults from atrophy in the cortex and particularly, the hippocampus, a region important to memory. We report the two-year effects of a randomized-controlled trial of an intergenerational social health promotion program on older men's and women's brain volumes. Methods The Brain Health Study simultaneously enrolled, evaluated and randomized 111 men and women (58 intervention; 53 control) within the Baltimore Experience Corps Trial to evaluate intervention impact on biomarkers of brain health at baseline and annual follow-ups during the two-year trial exposure. Results Intention-to-treat analyses on cortical and hippocampal volumes for full and sex-stratified samples revealed program-specific increases in volumes that reached significance in men only (p's≤0.04). Whereas men in the control arm exhibited age-related declines over two years, men in the Experience Corps arm showed a 0.7-1.6% increase in brain volumes. Women also exhibited modest intervention-specific gains of 0.3-0.54% by the second year of exposure that contrasted with declines of about 1% among women in the control group. Conclusions These findings showed that purposeful activity embedded within a social health promotion program halted and, in men, reversed declines in brain volume in regions vulnerable to dementia.

Our study demonstrated severe impairment of sleep quality in HD patients and corroborated the role of inflammation in the pathogenesis of sleep disturbance.

Cardiovascular (CV) risk factors, such as hypertension, diabetes, and hyperlipidemia are associated with cognitive impairment and risk of dementia in older adults. However, the mechanisms linking them are not clear. This study aims to investigate the association between aggregate CV risk, assessed by the Framingham general cardiovascular risk profile, and functional brain activation in a group of community-dwelling older adults. Sixty participants (mean age: 64.6 years) from the Brain Health Study, a nested study of the Baltimore Experience Corps Trial, underwent functional magnetic resonance imaging using the Flanker task. We found that participants with higher CV risk had greater task-related activation in the left inferior parietal region, and this increased activation was associated with poorer task performance. Our results provide insights into the neural systems underlying the relationship between CV risk and executive function. Increased activation of the inferior parietal region may offer a pathway through which CV risk increases risk for cognitive impairment.