Journal of the International Neuropsychological Society, 2015
Aerobic exercise training has been shown to attenuate cognitive decline and reduce brain atrophy ... more Aerobic exercise training has been shown to attenuate cognitive decline and reduce brain atrophy with advancing age. The extent to which resistance exercise training improves cognition and prevents brain atrophy is less known, and few studies include long-term follow-up cognitive and neuroimaging assessments. We report data from a randomized controlled trial of 155 older women, who engaged in 52 weeks of resistance training (either once- or twice-weekly) or balance-and-toning (twice-weekly). Executive functioning and memory were assessed at baseline, 1-year follow-up (i.e., immediately post-intervention), and 2-year follow-up. A subset underwent structural magnetic resonance imaging scans at those time points. At 2-year follow-up, both frequencies of resistance training promoted executive function compared to balance-and-toning (standardized difference [d]=.31-.48). Additionally, twice-weekly resistance training promoted memory (d=.45), reduced cortical white matter atrophy (d=.45), and increased peak muscle power (d=.27) at 2-year follow-up relative to balance-and-toning. These effects were independent of one another. These findings suggest resistance training may have a long-term impact on cognition and white matter volume in older women. (JINS, 2015, 21, 745-756).
Mixed pathology, particularly Alzheimer's disease with cerebrovascular lesions, is reported a... more Mixed pathology, particularly Alzheimer's disease with cerebrovascular lesions, is reported as the second most common cause of dementia. Research on mixed dementia typically includes people with a primary AD diagnosis and hence, little is known about the effects of co-existing amyloid pathology in people with vascular cognitive impairment (VCI). The purpose of this study was to understand whether individual differences in amyloid pathology might explain variations in cognitive impairment among individuals with clinical subcortical VCI (SVCI). Twenty-two participants with SVCI completed an (11)C Pittsburgh compound B (PIB) position emission tomography (PET) scan to quantify global amyloid deposition. Cognitive function was measured using: 1) MOCA; 2) ADAS-Cog; 3) EXIT-25; and 4) specific executive processes including a) Digits Forward and Backwards Test, b) Stroop-Colour Word Test, and c) Trail Making Test. To assess the effect of amyloid deposition on cognitive function we condu...
Obesity is associated with vascular risk factors that in turn, may increase dementia risk. Howeve... more Obesity is associated with vascular risk factors that in turn, may increase dementia risk. However, higher body mass index (BMI) in late life may be neuroprotective. The possible neural mechanisms underlying the benefit of higher BMI on cognition in older adults are largely unknown. Thus, we used functional connectivity magnetic resonance imaging (fcMRI) to examine: (1) the relationship between BMI and functional brain connectivity; and (2) the mediating role of functional brain connectivity in the association between baseline BMI and change in cognitive function over a 12-month period. We conducted a 12-month, prospective study among 66 community-dwelling older adults, aged 70 to 80 years, who were categorized as: normal weight (BMI from 18.50 to 24.99); overweight (BMI from 25.00 to 29.99); and obese (BMI ≥ 30.00). At baseline, participants performed a finger-tapping task during fMRI scanning. Relevant neural networks were initially identified through independent component analysis (ICA) and subsequently examined through seed-based functional connectivity analysis. At baseline and 12-months, we measured three executive cognitive processes: (1) response inhibition; (2) set shifting; and (3) working memory. Obese individuals showed lower task-related functional connectivity during finger tapping in the default mode network (DMN) compared with their healthy weight counterparts (p < 0.01). Lower task-related functional connectivity in the DMN at baseline was independently associated with better working memory performance at 12-months (p = 0.02). Finally, DMN functional connectivity during finger tapping significantly mediated the relationship between baseline BMI and working memory at 12-months (indirect effect: -0.155, 95% confidence interval [-0.313, -0.053]). These findings suggest that functional connectivity of the DMN may be an underlying mechanism by which higher BMI confers protective effects to cognition in late life.
Health psychology : official journal of the Division of Health Psychology, American Psychological Association, Jan 20, 2015
The primary objective was to determine whether children and their participating parents undergoin... more The primary objective was to determine whether children and their participating parents undergoing family-based behavioral treatment (FBT) for obesity show similar dietary changes following treatment, and if so, whether these shared dietary changes explain the similarity in weight change within the parent-child dyad. Data come from a randomized controlled trial of 148 parent-child dyads who completed FBT and were followed over a 2-year maintenance phase. Energy-dense, nutrient-poor foods ("RED" foods) and fruit and vegetable intake were assessed across time. Maintenance of lower RED food intake following FBT predicted weight maintenance in children and in parents (ps < .01), and dietary and weight changes were correlated within parent-child dyads (ps < .01). Most interesting, the similarity in long-term weight maintenance between children and their parents was predicted by the similarity in long-term changes in RED food intake between children and their parents (p &l...
Older adults with mobility impairments are prone to reduced health related quality of life (HRQoL... more Older adults with mobility impairments are prone to reduced health related quality of life (HRQoL) is highly associated with mobility impairments. The consequences of falls have detrimental impact on mobility. Hence, ascertaining factors explaining variation among individuals' quality of life is critical for promoting healthy ageing, particularly among older fallers. Hence, the primary objective of our study was to identify key factors that explain variation in HRQoL among community dwelling older adults at risk of falls. We conducted a longitudinal analysis of a 12-month prospective cohort study at the Vancouver Falls Prevention Clinic (n = 148 to 286 depending on the analysis). We constructed linear mixed models where assessment month (0, 6, 12) was entered as a within-subjects repeated measure, the intercept was specified as a random effect, and predictors and covariates were entered as between-subjects fixed effects. We also included the predictors by sex and predictor by se...
To examine whether good executive function (EF; the cognitive processes important for goal-orient... more To examine whether good executive function (EF; the cognitive processes important for goal-oriented and controlled behavior) at baseline and maintenance of EF over time predict maintenance of physical performance, functional status, physical activity, and mood over a 1-year period, and conversely, to examine whether baseline functioning in these noncognitive domains predicts maintenance of EF over the same period of time. 12-month prospective cohort study. Vancouver Falls Prevention Clinic. Community-dwelling older adults (N = 199; mean age 81.6 ± 6.5; 63% female) referred to the clinic after a fall. At each time point, structural equation modeling created a latent EF variable from performance on five EF tasks. Physical performance (physiological falls risk and gait speed), instrumental activities of daily living (IADLs), physical activity, and depressive symptoms were also assessed at each time point. Higher baseline EF predicted decreases in depressive symptoms (P = .005) and main...
Ascertaining individuals' quality of life and wellbeing is essential in public health and cli... more Ascertaining individuals' quality of life and wellbeing is essential in public health and clinical research. The impact of these two pressing geriatric syndromes - impaired mobility and cognitive function -- on wellbeing and quality of life is not well examined. Hence, our objective was to identify key clinically relevant outcome measures of mobility and cognitive function that explain variation in wellbeing and health related quality of life (HRQoL) among community dwelling older adults. We conducted a cross-sectional analysis of 229 participants presenting to the Vancouver Falls Prevention Clinic from June 2010 through October 2013. The linear regression models included two dependent variables: the ICECAP-O assessing wellbeing and the EQ-5D-3L assessing HRQoL. Key independent variables included the Short Performance Physical Battery (SPPB) and the Montreal Cognitive Assessment (MoCA). Covariates included Functional Comorbidity Index (FCI), sex and age. In the two multiple line...
Journal of consulting and clinical psychology, 2014
To examine general and treatment-specific predictors of children's weight outcomes during a p... more To examine general and treatment-specific predictors of children's weight outcomes during a pediatric weight management trial. One hundred fifty overweight children-69.3% female; M body mass index (BMI) z score (z-BMI) = 2.21 ± 0.30-completed family-based behavioral weight loss treatment (FBT), followed by randomization to social facilitation maintenance (SFM) treatment addressing social support and body image; behavioral skills maintenance treatment (BSM), which extended FBT skills to maintenance; or a control condition with no maintenance treatment. Regression and mixed-effects repeated-measures analysis of covariance (ANCOVA) examined child and parent anthropometric, demographic, and psychosocial variables in predicting relative weight outcomes over short- and long-term follow-ups. Among FBT completers, lower child baseline z-BMI and age, and greater parent BMI reductions during FBT and baseline self-efficacy, predicted better child relative weight loss following FBT, F(6, 13...
Journal of the International Neuropsychological Society, 2015
Aerobic exercise training has been shown to attenuate cognitive decline and reduce brain atrophy ... more Aerobic exercise training has been shown to attenuate cognitive decline and reduce brain atrophy with advancing age. The extent to which resistance exercise training improves cognition and prevents brain atrophy is less known, and few studies include long-term follow-up cognitive and neuroimaging assessments. We report data from a randomized controlled trial of 155 older women, who engaged in 52 weeks of resistance training (either once- or twice-weekly) or balance-and-toning (twice-weekly). Executive functioning and memory were assessed at baseline, 1-year follow-up (i.e., immediately post-intervention), and 2-year follow-up. A subset underwent structural magnetic resonance imaging scans at those time points. At 2-year follow-up, both frequencies of resistance training promoted executive function compared to balance-and-toning (standardized difference [d]=.31-.48). Additionally, twice-weekly resistance training promoted memory (d=.45), reduced cortical white matter atrophy (d=.45), and increased peak muscle power (d=.27) at 2-year follow-up relative to balance-and-toning. These effects were independent of one another. These findings suggest resistance training may have a long-term impact on cognition and white matter volume in older women. (JINS, 2015, 21, 745-756).
Mixed pathology, particularly Alzheimer's disease with cerebrovascular lesions, is reported a... more Mixed pathology, particularly Alzheimer's disease with cerebrovascular lesions, is reported as the second most common cause of dementia. Research on mixed dementia typically includes people with a primary AD diagnosis and hence, little is known about the effects of co-existing amyloid pathology in people with vascular cognitive impairment (VCI). The purpose of this study was to understand whether individual differences in amyloid pathology might explain variations in cognitive impairment among individuals with clinical subcortical VCI (SVCI). Twenty-two participants with SVCI completed an (11)C Pittsburgh compound B (PIB) position emission tomography (PET) scan to quantify global amyloid deposition. Cognitive function was measured using: 1) MOCA; 2) ADAS-Cog; 3) EXIT-25; and 4) specific executive processes including a) Digits Forward and Backwards Test, b) Stroop-Colour Word Test, and c) Trail Making Test. To assess the effect of amyloid deposition on cognitive function we condu...
Obesity is associated with vascular risk factors that in turn, may increase dementia risk. Howeve... more Obesity is associated with vascular risk factors that in turn, may increase dementia risk. However, higher body mass index (BMI) in late life may be neuroprotective. The possible neural mechanisms underlying the benefit of higher BMI on cognition in older adults are largely unknown. Thus, we used functional connectivity magnetic resonance imaging (fcMRI) to examine: (1) the relationship between BMI and functional brain connectivity; and (2) the mediating role of functional brain connectivity in the association between baseline BMI and change in cognitive function over a 12-month period. We conducted a 12-month, prospective study among 66 community-dwelling older adults, aged 70 to 80 years, who were categorized as: normal weight (BMI from 18.50 to 24.99); overweight (BMI from 25.00 to 29.99); and obese (BMI ≥ 30.00). At baseline, participants performed a finger-tapping task during fMRI scanning. Relevant neural networks were initially identified through independent component analysis (ICA) and subsequently examined through seed-based functional connectivity analysis. At baseline and 12-months, we measured three executive cognitive processes: (1) response inhibition; (2) set shifting; and (3) working memory. Obese individuals showed lower task-related functional connectivity during finger tapping in the default mode network (DMN) compared with their healthy weight counterparts (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). Lower task-related functional connectivity in the DMN at baseline was independently associated with better working memory performance at 12-months (p = 0.02). Finally, DMN functional connectivity during finger tapping significantly mediated the relationship between baseline BMI and working memory at 12-months (indirect effect: -0.155, 95% confidence interval [-0.313, -0.053]). These findings suggest that functional connectivity of the DMN may be an underlying mechanism by which higher BMI confers protective effects to cognition in late life.
Health psychology : official journal of the Division of Health Psychology, American Psychological Association, Jan 20, 2015
The primary objective was to determine whether children and their participating parents undergoin... more The primary objective was to determine whether children and their participating parents undergoing family-based behavioral treatment (FBT) for obesity show similar dietary changes following treatment, and if so, whether these shared dietary changes explain the similarity in weight change within the parent-child dyad. Data come from a randomized controlled trial of 148 parent-child dyads who completed FBT and were followed over a 2-year maintenance phase. Energy-dense, nutrient-poor foods ("RED" foods) and fruit and vegetable intake were assessed across time. Maintenance of lower RED food intake following FBT predicted weight maintenance in children and in parents (ps < .01), and dietary and weight changes were correlated within parent-child dyads (ps < .01). Most interesting, the similarity in long-term weight maintenance between children and their parents was predicted by the similarity in long-term changes in RED food intake between children and their parents (p &l...
Older adults with mobility impairments are prone to reduced health related quality of life (HRQoL... more Older adults with mobility impairments are prone to reduced health related quality of life (HRQoL) is highly associated with mobility impairments. The consequences of falls have detrimental impact on mobility. Hence, ascertaining factors explaining variation among individuals' quality of life is critical for promoting healthy ageing, particularly among older fallers. Hence, the primary objective of our study was to identify key factors that explain variation in HRQoL among community dwelling older adults at risk of falls. We conducted a longitudinal analysis of a 12-month prospective cohort study at the Vancouver Falls Prevention Clinic (n = 148 to 286 depending on the analysis). We constructed linear mixed models where assessment month (0, 6, 12) was entered as a within-subjects repeated measure, the intercept was specified as a random effect, and predictors and covariates were entered as between-subjects fixed effects. We also included the predictors by sex and predictor by se...
To examine whether good executive function (EF; the cognitive processes important for goal-orient... more To examine whether good executive function (EF; the cognitive processes important for goal-oriented and controlled behavior) at baseline and maintenance of EF over time predict maintenance of physical performance, functional status, physical activity, and mood over a 1-year period, and conversely, to examine whether baseline functioning in these noncognitive domains predicts maintenance of EF over the same period of time. 12-month prospective cohort study. Vancouver Falls Prevention Clinic. Community-dwelling older adults (N = 199; mean age 81.6 ± 6.5; 63% female) referred to the clinic after a fall. At each time point, structural equation modeling created a latent EF variable from performance on five EF tasks. Physical performance (physiological falls risk and gait speed), instrumental activities of daily living (IADLs), physical activity, and depressive symptoms were also assessed at each time point. Higher baseline EF predicted decreases in depressive symptoms (P = .005) and main...
Ascertaining individuals' quality of life and wellbeing is essential in public health and cli... more Ascertaining individuals' quality of life and wellbeing is essential in public health and clinical research. The impact of these two pressing geriatric syndromes - impaired mobility and cognitive function -- on wellbeing and quality of life is not well examined. Hence, our objective was to identify key clinically relevant outcome measures of mobility and cognitive function that explain variation in wellbeing and health related quality of life (HRQoL) among community dwelling older adults. We conducted a cross-sectional analysis of 229 participants presenting to the Vancouver Falls Prevention Clinic from June 2010 through October 2013. The linear regression models included two dependent variables: the ICECAP-O assessing wellbeing and the EQ-5D-3L assessing HRQoL. Key independent variables included the Short Performance Physical Battery (SPPB) and the Montreal Cognitive Assessment (MoCA). Covariates included Functional Comorbidity Index (FCI), sex and age. In the two multiple line...
Journal of consulting and clinical psychology, 2014
To examine general and treatment-specific predictors of children's weight outcomes during a p... more To examine general and treatment-specific predictors of children's weight outcomes during a pediatric weight management trial. One hundred fifty overweight children-69.3% female; M body mass index (BMI) z score (z-BMI) = 2.21 ± 0.30-completed family-based behavioral weight loss treatment (FBT), followed by randomization to social facilitation maintenance (SFM) treatment addressing social support and body image; behavioral skills maintenance treatment (BSM), which extended FBT skills to maintenance; or a control condition with no maintenance treatment. Regression and mixed-effects repeated-measures analysis of covariance (ANCOVA) examined child and parent anthropometric, demographic, and psychosocial variables in predicting relative weight outcomes over short- and long-term follow-ups. Among FBT completers, lower child baseline z-BMI and age, and greater parent BMI reductions during FBT and baseline self-efficacy, predicted better child relative weight loss following FBT, F(6, 13...
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