A systematic review of MRI studies examining the relationship between physical fitness and activity and the white matter of the ageing brain

Higher levels of physical fitness or activity (PFA) have been shown to have beneficial effects on cognitive function and grey matter volumes in older adults. However, the relationship between PFA and the brain's white matter (WM) is not yet well established. Here, we aim to provide a comprehensive and systematic review of magnetic resonance imaging studies examining the effects of PFA on the WM of the ageing brain. Twenty-nine studies were included in the review: eleven examined WM volume, fourteen WM lesions, and nine WM microstructure. While many studies found that higher levels of PFA were associated with greater WM volumes, reduced volume or severity of WM lesions, or improved measures of WM microstructure, a number of negative findings have also been published. Meta-analyses of global measures of WM volume and WM lesion volume yielded significant, but small, effect sizes. Overall, we found evidence for cautious support of links between PFA and WM structure, and highlighted key areas for future research including the extent to which the relationship between PFA and WM structure is anatomically specific, the influence of possible confounding factors, and the relationship between PFA, WM and cognition

Acute cognitive effects of physical activity for people who have dementia

Background: Physical activity has the potential to improve cognition for those with dementia, as demonstrated by randomised controlled trials lasting at least 6 weeks. Research is yet to explore the acute cognitive effects of physical activity for people with dementia. Acute resistance physical activity with healthy late-middle aged individuals has been shown to facilitate general cognition, as well as benefit executive function specifically. This study therefore aimed to establish if people with dementia experience cognitive benefits from acute resistance physical activity over and above a social control.Methods: A cross-sectional study design was applied to compare resistance physical activity to bingo between 10 participants with dementia to 15 age-matched controls. Following University ethical approval, participants were recruited from Alzheimer’s or dementia activity and support groups held in the community. Acute cognitive effects were assessed using the Mini Mental Status Examination (MMSE), Hopkins Verbal Learning Test (HVLT), Verbal Fluency (VF) and The Cognitive Computerised Test Battery for Individual’s with Intellectual Disabilities (CCIID); before and after a short bout of seated resistance band physical activity or a social control, bingo. The participants then completed the opposing activity 6 weeks later, and then cognitive assessments alone a further 6 weeks later. This allowed to analyse cognitive effects immediately and 6 weeks after. Statistical analysis included Mann Whitney U test, Chi-square test and Mix-measured ANOVA to compare scores across time-points.Results: Participants had a mean age of 76 years, 40% were male and 60% were female. For participants with dementia immediately after the resistance band activity improvements can be observed on the MMSE, VF, HVLT, Series, Jigsaw and Total CCIID. Only the MMSE, Series and Total CCIID still showed improvements at 6-week follow-up. Immediately following the psychosocial intervention, participants with dementia only showed improvements on the HVLT, which were not sustained after 6-weeks. For age-matched controls, bingo appeared to be more beneficial than physical activity.Conclusion: These results indicate that there are differential acute effects of activity depending upon pre-existing cognitive ability. Specific cognitive benefits may be available for people with dementia following resistance band physical activity. This pilot study shows promising indications for physical activity as a therapy for dementia, however results should be interpreted with caution due to the small sample size of this study.</div

Comprehensive Assessment of Sleep Duration, Insomnia and Brain Structure within the UK Biobank Cohort

STUDY OBJECTIVES: To assess for associations between sleeping more than or less than recommended by the National Sleep Foundation (NSF), and self-reported insomnia, with brain structure. METHODS: Data from the UK Biobank cohort were analysed (N between 9K and 32K, dependent on availability, aged 44 to 82 years). Sleep measures included self-reported adherence to NSF guidelines on sleep duration (sleeping between 7 and 9 hours per night), and self-reported difficulty falling or staying asleep (insomnia). Brain structural measures included global and regional cortical or subcortical morphometry (thickness, surface area, volume), global and tract-related white matter microstructure, brain age gap (difference between chronological age and age estimated from brain scan), and total volume of white matter lesions. RESULTS: Longer-than-recommended sleep duration was associated with lower overall grey and white matter volumes, lower global and regional cortical thickness and volume measures, higher brain age gap, higher volume of white matter lesions, higher mean diffusivity globally and in thalamic and association fibers, and lower volume of the hippocampus. Shorter-than-recommended sleep duration was related to higher global and cerebellar white matter volumes, lower global and regional cortical surface areas, and lower fractional anisotropy in projection fibers. Self-reported insomnia was associated with higher global grey and white matter volumes, and with higher volumes of the amygdala, hippocampus and putamen. CONCLUSIONS: Sleeping longer than recommended by the NSF is associated with a wide range of differences in brain structure, potentially indicative of poorer brain health. Sleeping less than recommended is distinctly associated with lower cortical surface areas. Future studies should assess the potential mechanisms of these differences and investigate long sleep duration as a putative marker of brain health

Med Sci Sports Exerc

Purpose:Physical activity (PA) is known to improve cognitive and brain function, but debate continues regarding the consistency and magnitude of its effects, populations and cognitive domains most affected, and parameters necessary to achieve the greatest improvements (e.g., dose).Methods:In this umbrella review conducted in part for the 2018 Health and Human Services Physical Activity Guidelines for Americans Advisory Committee, we examined whether PA interventions enhance cognitive and brain outcomes across the lifespan, as well as in populations experiencing cognitive dysfunction (e.g., schizophrenia). Systematic reviews, meta-analyses, and pooled analyses were used. We further examined whether engaging in greater amounts of PA is associated with a reduced risk of developing cognitive impairment and dementia in late adulthood.Results:Moderate evidence from randomized controlled trials indicates an association between moderate-to-vigorous intensity PA and improvements in cognition, including performance on academic achievement and neuropsychological tests, such as those measuring processing speed, memory, and executive function. Strong evidence demonstrates that acute bouts of moderate-to-vigorous PA have transient benefits for cognition during the post-recovery period following exercise. Strong evidence demonstrates that greater amounts of PA are associated with a reduced risk of developing cognitive impairment, including Alzheimer\u2019s disease. The strength of the findings varies across the lifespan and in individuals with medical conditions influencing cognition.Conclusions:There is moderate-to-strong support that PA benefits cognitive functioning during early and late periods of the lifespan and in certain populations characterized by cognitive deficits.Z99 OD999999/CD/ODCDC CDC HHS/United States2020-06-01T00:00:00Z31095081PMC65271416559vault:3371

Using structural and functional MRI as a neuroimaging technique to investigate chronic fatigue syndrome/myalgic encephalopathy: a systematic review.

OBJECTIVE: This systematic review aims to synthesise and evaluate structural MRI (sMRI) and functional MRI (fMRI) studies in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). METHODS: We systematically searched Medline and Ovid and included articles from 1991 (date of Oxford diagnostic criteria for CFS/ME) to first April 2019. Studies were selected by predefined inclusion and exclusion criteria. Two reviewers independently reviewed the titles and abstracts to determine articles for inclusion, full text and quality assessment for risk of bias. RESULTS: sMRI studies report differences in CFS/ME brain anatomy in grey and white matter volume, ventricular enlargement and hyperintensities. Three studies report no neuroanatomical differences between CFS/ME and healthy controls. Task-based fMRI investigated working memory, attention, reward and motivation, sensory information processing and emotional conflict. The most consistent finding was CFS/ME exhibited increased activations and recruited additional brain regions. Tasks with increasing load or complexity produced decreased activation in task-specific brain regions. CONCLUSIONS: There were insufficient data to define a unique neural profile or biomarker of CFS/ME. This may be due to inconsistencies in finding neuroanatomical differences in CFS/ME and the variety of different tasks employed by fMRI studies. But there are also limitations with neuroimaging. All brain region specific volumetric differences in CFS/ME were derived from voxel-based statistics that are biased towards group differences that are highly localised in space. fMRI studies demonstrated both increases and decreases in activation patterns in CFS/ME, this may be related to task demand. However, fMRI signal cannot differentiate between neural excitation and inhibition or function-specific neural processing. Many studies have small sample sizes and did not control for the heterogeneity of this clinical population. We suggest that with robust study design, subgrouping and larger sample sizes, future neuroimaging studies could potentially lead to a breakthrough in our understanding of the disease

Does exercise have a neuroprotective function in multiple sclerosis? A brief overview of the physical training potential effects on cytokines and brain-derived neurotrophic factor.

Although the advance in disease-modifying drugs has helped to stabilize the multiple sclerosis (MS) course increasing life-expectancy, physical deterioration still supervenes over time in most MS patients. In this context, physical exercise programs are considered a safe and well-tolerated tool to preserve functional independence in this population, which not only provides similar fitness improvements as usually observed in healthy general population, but it may also ameliorate some of the symptoms that this pathology entails (as fatigue, balance deficits, muscle weakness, etc.). Nowadays, the question is if exercise only aids to reverse physical deconditioning associated to the disease or it has the potential to have an impact on MS progression. In the present overview, the role of exercise as complementary therapy for modulating various physiopathological pathways related to MS disease such as inflammation and the neurotrophic support for neuronal survival was revised. Specifically, the exercise ability to modulate the immune system behaviour regulating the pro- and anti-inflammatory cytokine balance, as well as, to promote neuroprotective and neurorestorative mechanisms through the brain-derived neurotrophic factor stimulation was analysed.post-print304

Physical inactivity amplifies the negative association between sleep quality and depressive symptoms.

Poor sleep quality and physical inactivity are known risk factors for depressive symptoms. Yet, whether these factors differently contribute to depressive symptoms and whether they interact with one another remains unclear. Here, we examined how sleep quality and physical activity influence depressive symptoms in 79,274 adults 50 years of age or older (52.4% women) from the Survey of Health, Aging and Retirement in Europe (SHARE) study. Sleep quality (poor vs. good), physical activity (inactive vs. active), and depressive symptoms (0 to 12 score) were repeatedly collected (7 waves of data collection) between 2004 and 2017. Results showed that sleep quality and physical activity were associated with depressive symptoms. Specifically, participants with poorer sleep quality reported more depressive symptoms than participants with better sleep quality (b = 1.85, 95% CI = 1.83-1.86, p &lt; .001). Likewise, compared to physically active participants, physically inactive participants reported more depressive symptoms (b = 0.44, 95% CI = 0.42-0.45, p &lt; .001). Moreover, sleep quality and physical activity showed an interactive association with depressive symptoms (b = 0.17, 95% CI = 0.13-0.20, p &lt; .001). The negative association between poor sleep quality and higher depressive symptoms was stronger in physically inactive than active participants. These findings suggest that, in adults 50 years of age or older, both poor sleep quality and physical inactivity are related to an increase in depressive symptoms. Moreover, the detrimental association between poor sleep quality and depressive symptoms is amplified in physically inactive individuals

Physical Activity Predicts Population-Level Age-Related Differences in Frontal White Matter.

Physical activity has positive effects on brain health and cognitive function throughout the life span. Thus far, few studies have examined the effects of physical activity on white matter microstructure and psychomotor speed within the same, population-based sample (critical if conclusions are to extend to the wider population). Here, using diffusion tensor imaging and a simple reaction time task within a relatively large population-derived sample (N = 399; 18-87 years) from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN), we demonstrate that physical activity mediates the effect of age on white matter integrity, measured with fractional anisotropy. Higher self-reported daily physical activity was associated with greater preservation of white matter in several frontal tracts, including the genu of corpus callosum, uncinate fasciculus, external capsule, and anterior limb of the internal capsule. We also show that the age-related slowing is mediated by white matter integrity in the genu. Our findings contribute to a growing body of work, suggesting that a physically active lifestyle may protect against age-related structural disconnection and slowing