Until recently, gait was generally viewed as a largely automated motor task, requiring minimal higher-level cognitive input. Increasing evidence, however, links alterations in executive function and attention to gait disturbances. This review discusses the role of executive function and of attention in healthy walking and gait disorders while summarizing the relevant, recent literature. We describe the variety of gait disorders that may be associated with different aspects of executive function, and discuss the changes occurring in executive function as a result of aging and disease as well the potential impact of these changes on gait. The attentional demands of gait are often tested using dual tasking methodologies. Relevant studies in healthy adults and patients are presented, as are the possible mechanisms responsible for the deterioration of gait during dual tasking. Lastly, we suggest how assessments of executive function and attention could be applied in the clinical setting as part of the process of identifying and understanding gait disorders and fall risk.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mds.21720

The role of executive function and attention in gait

Context Many observational studies have shown that physical activity reduces the risk of cognitive decline; however, evidence from randomized trials is lacking. Objective To determine whether physical activity reduces the rate of cognitive decline among older adults at risk. Design and Setting Randomized controlled trial of a 24-week physical activity intervention conducted between 2004 and 2007 in metropolitan Perth, Western Australia. Assessors of cognitive function were blinded to group membership. Participants We recruited volunteers who reported memory problems but did not meet criteria for dementia. Three hundred eleven individuals aged 50 years or older were screened for eligibility, 89 were not eligible, and 52 refused to participate. A total of 170 participants were randomized and 138 participants completed the 18-month assessment. Intervention Participants were randomly allocated to an education and usual care group or to a 24-week home-based program of physical activity. Main Outcome Measure Change in Alzheimer Disease Assessment Scale–Cognitive Subscale (ADAS-Cog) scores (possible range, 0-70) over 18 months. Results In an intent-to-treat analysis, participants in the intervention group improved 0.26 points (95% confidence interval, −0.89 to 0.54) and those in the usual care group deteriorated 1.04 points (95% confidence interval, 0.32 to 1.82) on the ADAS-Cog at the end of the intervention. The absolute difference of the outcome measure between the intervention and control groups was −1.3 points (95% confidence interval,−2.38 to −0.22) at the end of the intervention. At 18 months, participants in the intervention group improved 0.73 points (95% confidence interval, −1.27 to 0.03) on the ADAS-Cog, and those in the usual care group improved 0.04 points (95% confidence interval, −0.46 to 0.88). Word list delayed recall and Clinical Dementia Rating sum of boxes improved modestly as well, whereas word list total immediate recall, digit symbol coding, verbal fluency, Beck depression score, and Medical Outcomes 36-Item Short-Form physical and mental component summaries did not change significantly. Conclusions In this study of adults with subjective memory impairment, a 6-month program of physical activity provided a modest improvement in cognition over an 18-month follow-up period. Trial Registration anzctr.org.au Identifier: ACTRN12605000136606

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Effect of physical activity on cognitive function in older adults at risk for Alzheimer disease: a randomized trial.

Physical activity is beneficial for healthy ageing. It may also help maintain good cognitive function in older age. Aerobic activity improves cardiovascular fitness, but it is not known whether this sort of fitness is necessary for improved cognitive function. Eleven studies of aerobic physical activity programmes for healthy people over the age of 55 years have been included in this review. Eight of these 11 studies reported that aerobic exercise interventions resulted in increased fitness of the trained group and an improvement in at least one aspect of cognitive function. The largest effects were on cognitive speed, auditory and visual attention. However, the cognitive functions which improved were not the same in each study and the majority of comparisons yielded no significant results. The data are insufficient to show that the improvements in cognitive function which can be attributed to physical exercise are due to improvements in cardiovascular fitness.

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Physical activity and enhanced fitness to improve cognitive function in older people without known cognitive impairment

Background. The association between physical activity and risk of neurodegenerative diseases is not well established. We therefore aimed to quantify this association using meta-analytical techniques.Method. We searched Medline, the Cochrane Database of Systematic Reviews and Web of Science databases from 1990 to 2007 for prospective epidemiological studies of physical activity and incident dementia, Alzheimer's and Parkinson's disease. We excluded studies of physical activity and cognitive decline without diagnosis of a neurodegenerative disease. Information on study design, participant characteristics, measurement of exposure and outcome variables, adjustment for potential confounding, and estimates of associations was abstracted independently by the two investigators.Results. We included 16 prospective studies in the overall analysis, which incorporated 163797 non-demented participants at baseline with 3219 cases at follow-up. We calculated pooled relative risk (RR) using a random effects model. The RR of dementia in the highest physical activity category compared with the lowest was 0.72 [95% confidence interval (CI) 0.60-0.86, p < 0.001], for Alzheimer's, 0.55 (95% CI 0.36-0.84, p = 0.006), and for Parkinson's 0.82 (95%, CI 0.57-1.18, p = 0.28).Conclusions. Our results suggest that physical activity is inversely associated with risk of dementia. Future studies should examine the optimal dose of physical activity to induce protection, which presently remains unclear.

Physical activity and risk of neurodegenerative disease: a systematic review of prospective evidence.

The purpose was to conduct systematic reviews of the relationship between physical activity of healthy community-dwelling older (>65 years) adults and outcomes of functional limitations, disability, or loss of independence. Prospective cohort studies with an outcome related to functional independence or to cognitive function were searched, as well as exercise training interventions that reported a functional outcome. Electronic database search strategies were used to identify citations which were screened (title and abstract) for inclusion. Included articles were reviewed to complete standardized data extraction tables, and assess study quality. An established system of assessing the level and grade of evidence for recommendations was employed. Sixty-six studies met inclusion criteria for the relationship between physical activity and functional independence, and 34 were included with a cognitive function outcome. Greater physical activity of an aerobic nature (categorized by a variety of methods) was associated with higher functional status (expressed by a host of outcome measures) in older age. For functional independence, moderate (and high) levels of physical activity appeared effective in conferring a reduced risk (odds ratio ~0.5) of functional limitations or disability. Limitation in higher level performance outcomes was reduced (odds ratio ~0.5) with vigorous (or high) activity with an apparent dose-response of moderate through to high activity. Exercise training interventions (including aerobic and resistance) of older adults showed improvement in physiological and functional measures, and suggestion of longer-term reduction in incidence of mobility disability. A relatively high level of physical activity was related to better cognitive function and reduced risk of developing dementia; however, there were mixed results of the effects of exercise interventions on cognitive function indices. There is a consistency of findings across studies and a range of outcome measures related to functional independence; regular aerobic activity and short-term exercise programmes confer a reduced risk of functional limitations and disability in older age. Although a precise characterization of a minimal or effective physical activity dose to maintain functional independence is difficult, it appears moderate to higher levels of activity are effective and there may be a threshold of at least moderate activity for significant outcomes.

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Physical activity and functional limitations in older adults: A systematic review related to Canada's Physical Activity Guidelines.

Background: Physical activity may be associated with better cognition. Objective: To investigate whether change in duration and intensity of physical activity is associated with 10-year cognitive decline in elderly men. Methods: Data of 295 healthy survivors, born between 1900 and 1920, from the Finland, Italy, and the Netherlands Elderly (FINE) Study were used. From 1990 onward, physical activity was measured with a validated questionnaire for retired men and cognitive functioning with the Mini-Mental State Examination (maximum score 30 points). Results: The rates of cognitive decline did not differ among men with a high or low duration of activity at baseline. However, a decrease in activity duration of >60 min/day over 10 years resulted in a decline of 1.7 points ( p p = 0.06). Men in the lowest intensity quartile at baseline had a 1.8 ( p = 0.07) to 3.5 ( p = 0.004) times stronger 10-year cognitive decline than those in the other quartiles. A decrease in intensity of physical activity of at least half a standard deviation was associated with a 3.6 times stronger decline than maintaining the level of intensity ( p = 0.003). Conclusions: Even in old age, participation in activities with at least a medium-low intensity may postpone cognitive decline. Moreover, a decrease in duration or intensity of physical activity results in a stronger cognitive decline than maintaining duration or intensity.

Physical activity in relation to cognitive decline in elderly men The FINE Study

Coffee consumption is inversely associated with cognitive decline in elderly European men: the FINE Study

Coffee consumption is inversely associated with cognitive decline in elderly European men: the FINE Study.

Objective: This study investigates the association between 5-year change in cognitive functioning and subsequent mortality. Methods: Four hundred and ninety-three

B.M. van Gelder

Papers

Physical activity in relation to cognitive decline in elderly men The FINE Study

Coffee consumption is inversely associated with cognitive decline in elderly European men: the FINE Study.

Decline in cognitive functioning is associated with a higher mortality risk.