Teresa Liu-Ambrose

Resistance Training and Executive Functions: A 12-Month Randomized Controlled Trial

BACKGROUND Cognitive decline among seniors is a pressing health care issue. Specific exercise training may combat cognitive decline. We compared the effect of once-weekly and twice-weekly resistance training with that of twice-weekly balance and tone exercise training on the performance of executive cognitive functions in senior women. METHODS In this single-blinded randomized trial, 155 community-dwelling women aged 65 to 75 years living in Vancouver were randomly allocated to once-weekly (n = 54) or twice-weekly (n = 52) resistance training or twice-weekly balance and tone training (control group) (n = 49). The primary outcome measure was performance on the Stroop test, an executive cognitive test of selective attention and conflict resolution. Secondary outcomes of executive cognitive functions included set shifting as measured by the Trail Making Tests (parts A and B) and working memory as assessed by verbal digit span forward and backward tests. Gait speed, muscular function, and whole-brain volume were also secondary outcome measures. RESULTS Both resistance training groups significantly improved their performance on the Stroop test compared with those in the balance and tone group (P < or = .03). Task performance improved by 12.6% and 10.9% in the once-weekly and twice-weekly resistance training groups, respectively; it deteriorated by 0.5% in the balance and tone group. Enhanced selective attention and conflict resolution was significantly associated with increased gait speed. Both resistance training groups demonstrated reductions in whole-brain volume compared with the balance and tone group at the end of the study (P < or = .03). CONCLUSION Twelve months of once-weekly or twice-weekly resistance training benefited the executive cognitive function of selective attention and conflict resolution among senior women. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00426881.

Exercise, brain, and cognition across the life span

This is a brief review of current evidence for the relationships between physical activity and exercise and the brain and cognition throughout the life span in non-pathological populations. We focus on the effects of both aerobic and resistance training and provide a brief overview of potential neurobiological mechanisms derived from non-human animal models. Whereas research has focused primarily on the benefits of aerobic exercise in youth and young adult populations, there is growing evidence that both aerobic and resistance training are important for maintaining cognitive and brain health in old age. Finally, in these contexts, we point out gaps in the literature and future directions that will help advance the field of exercise neuroscience, including more studies that explicitly examine the effect of exercise type and intensity on cognition, the brain, and clinically significant outcomes. There is also a need for human neuroimaging studies to adopt a more unified multi-modal framework and for greater interaction between human and animal models of exercise effects on brain and cognition across the life span.

A review of the effects of physical activity and exercise on cognitive and brain functions in older adults.

Studies supporting the notion that physical activity and exercise can help alleviate the negative impact of age on the body and the mind abound. This literature review provides an overview of important findings in this fast growing research domain. Results from cross-sectional, longitudinal, and intervention studies with healthy older adults, frail patients, and persons suffering from mild cognitive impairment and dementia are reviewed and discussed. Together these finding suggest that physical exercise is a promising nonpharmaceutical intervention to prevent age-related cognitive decline and neurodegenerative diseases.

Resistance training promotes cognitive and functional brain plasticity in seniors with probable mild cognitive impairment.

Lindsay S. Nagamatsu, MA1,2,3, Todd C. Handy, PhD1,2, C. Liang Hsu, BSc2,3,4, Michelle Voss, PhD5, and Teresa Liu-Ambrose, PT, PhD2,3,4 1Department of Psychology, University of British Columbia, Vancouver, BC, Canada 2The Brain Research Centre, Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, BC, Canada 3The Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, BC, Canada 4Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada 5University of Illinois at Urbana-Champaign, The Beckman Institute for Advanced Science and Technology

Resistance training and functional plasticity of the aging brain: a 12-month randomized controlled trial

Maintaining functional plasticity of the cortex is essential for healthy aging and aerobic exercise may be an effective behavioral intervention to promote functional plasticity among seniors. Whether resistance training has similar benefits on functional plasticity in seniors has received little investigation. Here we show that 12 months of twice-weekly resistance training led to functional changes in 2 regions of cortex previously associated with response inhibition processes-the anterior portion of the left middle temporal gyrus and the left anterior insula extending into lateral orbital frontal cortex-in community-dwelling senior women. These hemodynamic effects co-occurred with improved task performance. Our data suggest that resistance training improved flanker task performance in 2 ways: (1) an increased engagement of response inhibition processes when needed; and (2) a decreased tendency to prepare response inhibition as a default state. However, we highlight that this effect of resistance training was only observed among those who trained twice weekly; participants of the once-weekly resistance training did not demonstrate comparable response profiles, both in behavioral performance and hemodynamic activity in cortex. In sum, our findings suggest that twice-weekly resistance training in seniors can positively impact functional plasticity of response inhibition processes in cortex, and that it does so in a manner that complements the effects on selective attention that have previously been ascribed to aerobic exercise in seniors.

Increased Risk of Falling in Older Community-Dwelling Women With Mild Cognitive Impairment

Background: Falls are a major health care problem for older people and are associated with cognitive dysfunction. Mild cognitive impairment (MCI) is an increasingly recognized clinical problem. No study has comprehensively compared people with and without MCI for fall risk factors in both the physiological and cognitive domains. Objective: The purpose of this cross-sectional study was to comprehensively compare fall risk factors in community-dwelling older women with and without MCI. Design: A cross-sectional design was used in the study. Methods: Community-dwelling women (N=158) with Folstein Mini Mental State Examination scores of ≥24 participated in the study. The Montreal Cognitive Assessment (MoCA) was used to categorize participants as either having or not having MCI. Each participants fall risk profile was assessed with the Physiological Profile Assessment (PPA). Three central executive functions were assessed: (1) set shifting was assessed with the Trail Making Test (part B), (2) updating (ie, working memory) was assessed with the Verbal Digits Backward Test, and (3) response inhibition was assessed with the Stroop Colour-Word Test. Results: Both the composite PPA score and its subcomponent, postural sway performance, were significantly different between the 2 groups; participants with MCI had higher composite PPA scores and greater postural sway compared with participants without MCI. Participants with MCI performed significantly worse on all 3 central executive function tests compared with participants without MCI. Limitations: A screening tool was used to categorize participants as having MCI, and fall risk factors were compared rather than the actual incidence of falls. Conclusions: Fall risk screening may be prudent in older adults with MCI.

Exercise and cognition in older adults: is there a role for resistance training programmes?

In recent years, there has been a strong interest in physical activity as a primary behavioural prevention strategy against cognitive decline. A number of large prospective cohort studies have highlighted the protective role of regular physical activity in lowering the risk of cognitive impairment and dementia. Most prospective intervention studies of exercise and cognition to date have focused on aerobic-based exercise training. These studies highlight that aerobic-based exercise training enhances both brain structure and function. However, it has been suggested that other types of exercise training, such as resistance training, may also benefit cognition. The purpose of this brief review is to examine the evidence regarding resistance training and cognitive benefits. Three recent randomised exercise trials involving resistance training among seniors provide evidence that resistance training may have cognitive benefits. Resistance training may prevent cognitive decline among seniors via mechanisms involving insulin-like growth factor I and homocysteine. A side benefit of resistance training, albeit a very important one, is its established role in reducing morbidity among seniors. Resistance training specifically moderates the development of sarcopenia. The multifactorial deleterious sequelae of sarcopenia include increased falls and fracture risk as well as physical disability. Thus, clinicians should consider encouraging their clients to undertake both aerobic-based exercise training and resistance training not only for “physical health” but also because of the almost certain benefits for “brain health”.

Does a home-based strength and balance programme in people aged ≥80 years provide the best value for money to prevent falls? A systematic review of economic evaluations of falls prevention interventions

Objectives To investigate the value for money of strategies to prevent falls in older adults living in the community. Design Systematic review of peer reviewed journal articles reporting an economic evaluation of a falls prevention intervention as part of a randomised controlled trial or a controlled trial, or using an analytical model. MEDLINE, PUBMED, EMBASE and NHS EED databases were searched to identify cost-effectiveness, cost–utility and cost–benefit studies from 1945 through July 2008. Main outcome measures The primary outcome measure was incremental cost-effectiveness, cost–utility and cost–benefit ratios in the reported currency and in pounds sterling at 2008 prices. The quality of the studies was assessed using two instruments: (1) an economic evaluation checklist developed by Drummond and colleagues and (2) the Quality of Health Economic Studies instrument. Results Nine studies meeting our inclusion criteria included eight cost-effectiveness analyses, one cost–utility and one cost–benefit analysis. Three effective falls prevention strategies were cost saving in a subgroup of participants: (1) an individually customised multifactorial programme in those with four or more of the eight targeted fall risk factors, (2) the home-based Otago Exercise Programme in people ≥80 years and (3) a home safety programme in the subgroup with a previous fall. These three findings were from six studies that scored ≥75% on the Quality of Health Economic Studies instrument. Conclusions Best value for money came from effective single factor interventions such as the Otago Exercise Programme which was cost saving in adults 80 years and older. This programme has broad applicability thus warranting warrants health policy decision-makers’ close scrutiny.

Aerobic exercise increases hippocampal volume in older women with probable mild cognitive impairment: a 6-month randomised controlled trial

Background Mild cognitive impairment (MCI) is a well-recognised risk factor for dementia and represents a vital opportunity for intervening. Exercise is a promising strategy for combating cognitive decline by improving brain structure and function. Specifically, aerobic training (AT) improved spatial memory and hippocampal volume in healthy community-dwelling older adults. In older women with probable MCI, we previously demonstrated that resistance training (RT) and AT improved memory. In this secondary analysis, we investigated: (1) the effect of RT and AT on hippocampal volume and (2) the association between change in hippocampal volume and change in memory. Methods 86 women aged 70–80 years with probable MCI were randomly assigned to a 6-month, twice-weekly programme of: (1) AT, (2) RT or (3) balance and tone training (BAT; ie, control). At baseline and trial completion, participants performed a 3T MRI scan to determine hippocampal volume. Verbal memory and learning were assessed by Reys Auditory Verbal Learning Test. Results Compared with the BAT group, AT significantly improved left, right and total hippocampal volumes (p≤0.03). After accounting for baseline cognitive function and experimental group, increased left hippocampal volume was independently associated with reduced verbal memory and learning performance as indexed by loss after interference (r=0.42, p=0.03). Conclusions Aerobic training significantly increased hippocampal volume in older women with probable MCI. More research is needed to ascertain the relevance of exercise-induced changes in hippocampal volume on memory performance in older adults with MCI. Trail registration number NCT00958867.

Physical activity as a mediator of the impact of chronic conditions on quality of life in older adults

BackgroundChronic conditions could negatively affect the quality of life of older adults. This may be partially due to a relative lack of physical activity. We examined whether physical activity mediates the relationship between different chronic conditions and several health outcomes that are important to the quality of life of older adults.MethodsThe data were taken from the Canadian Community Health Survey (cycle 1.1), a cross-section survey completed in 2001. Only respondents who were 65 years or older were included in our study (N = 22,432). The Health Utilities Index Mark 3 (HUI3) was used to measure overall quality of life, and to measure selected health outcomes (dexterity, mobility, pain, cognition, and emotional wellbeing) that are considered to be of importance to the quality of life of older adults. Leisure-time physical activity was assessed by determining weekly energy expenditure (Kcal per week) based on the metabolic equivalents of self-reported leisure activities. Linear and logistic regression models were used to determine the mediating effect of leisure-time physical activity while controlling for demographic variables (age and sex), substance use (tobacco use and alcohol consumption), and obesity.ResultsHaving a chronic condition was associated with a relative decrease in health utility scores and a relative increase in mobility limitations, dexterity problems, pain, emotional problems (i.e., decreased happiness), and cognitive limitations. These negative consequences could be partially attributed to a relative lack of physical activity in older adults with a chronic condition (14% mediation for the HUI3 score). The corresponding degree of mediation was 18% for mobility limitations, 5% for pain, and 13% for emotional wellbeing (statistically significant mediation was not observed for the other health attributes). These values varied with respect to the different chronic conditions examined in our study.ConclusionOlder adults with chronic conditions are less likely to engage in leisure-time physical activities of at least 1,000 Kcal per week, and this association partially accounts for some negative consequences of chronic conditions, including mobility limitations, pain, and emotional problems. These findings provide support for health promotion programs that facilitate or encourage increased leisure-time physical activity in older people with chronic conditions.