Cognitive performances better identify fallers than mobility assessment among older adults with fear of falling.

BACKGROUND: Half of the people with fear of falling (FoF) are non-fallers, and the reason why some people considered non-fallers are afraid of falling is unknown, but reduced mobility or cognition, or both concurrently must be considered as potential risk factors. AIM: The study aimed to determine if mobility and/or cognitive abilities could identify people with a history of falls in older adults with FoF. METHODS: Twenty-six older adults with FoF participated in this study. Full cognitive and mobility assessments were performed assessing global cognitive impairments (MoCA score < 26), executive functions, memory, processing speed, visuospatial skills, mobility impairment (TUG time > 13.5 s), gait, balance and physical capacity. Information about falls occurring during the year prior to the inclusion was collected. Logistic regression analyses were performed to explore the association between falls and cognitive and mobility abilities. RESULTS: No significant differences in age, sex, level of education or body mass index were detected between fallers and non-fallers. Cognitive impairments (MoCA score < 26) distinguished between fallers and non-fallers (p = 0.038; R2 = 0.247). Among specific cognitive functions, visuospatial skills distinguished between fallers and non-fallers (p = 0.027; R2 = 0.258). Mobility impairments (TUG time > 13.5 s), gait, balance and physical capacity were not related to past falls. DISCUSSION/CONCLUSION: In older adults with FoF, global cognitive deficits detected by the MoCA are important factors related to falls and more particularly visuospatial skills seem to be among the most implicated functions. These functions could be targeted in multifactorial interventions.

Arterial stiffness and white matter integrity in the elderly: A diffusion tensor and magnetization transfer imaging study.

BACKGROUND AND PURPOSE: The stiffness of large arteries and increased pulsatility can have an impact on the brain white matter (WM) microstructure, however those mechanisms are still poorly understood. The aim of this study was to investigate the association between central artery stiffness, axonal and myelin integrity in 54 cognitively unimpaired elderly subjects (65-75 years old). METHODS: The neuronal fiber integrity of brain WM was assessed using diffusion tensor metrics and magnetization transfer imaging as measures of axonal organization (Fractional anisotropy, Radial diffusivity) and state of myelination (Myelin volume fraction). Central artery stiffness was measured by carotid-femoral pulse wave velocity (cfPWV). Statistical analyses included 4 regions (the corpus callosum, the internal capsule, the corona radiata and the superior longitudinal fasciculus) which have been previously denoted as vulnerable to increased central artery stiffness. RESULTS: cfPWV was significantly associated with fractional anisotropy and radial diffusivity (p < 0.05, corrected for multiple comparisons) but not with myelin volume fraction. Findings from this study also show that improved executive function performance correlates with Fractional anisotropy positively (p < 0.05 corrected) as well as with myelin volume fraction and radial diffusivity negatively (p < 0.05 corrected). CONCLUSIONS: These findings suggest that arterial stiffness is associated with axon degeneration rather than demyelination. Controlling arterial stiffness may play a role in maintaining the health of WM axons in the aging brain.

The Effects of Multi-Component Exercise Training on Cognitive Functioning and Health-Related Quality of Life in Older Adults.

PURPOSE: Exercise has been shown to have various proximal and distal benefits among older adults such as improving physical fitness, cognitive functioning, and health-related quality of life (HR-QOL). Despite this evidence, limited research has investigated pathway change of these outcomes. The primary purpose of this study was to test if older adults who improved in physical fitness measures from engaging in multicomponent exercise training for 12 weeks predicted change in proximal (cognitive functioning) and distal (HR-QOL) outcomes, respectively. METHODS: Participants (n = 110) were healthy, older adults (M = 72, SD = 7.24) that comprised an exercise-intervention and control group. The intervention consisted of exercising in a supervised laboratory setting for 12 weeks. RESULTS: Structural equation modeling revealed group type to predict change in physical performance and the maximum walking test with comparable effect sizes. Physical performance in turn predicted improvement in processing speed (ß = 0.23, p = 0.013) executive functioning (ß = 0.26, p = 0.006), and HR-QOL (ß = 0.13, p = 0.031). However, only executive functioning was found to significantly predict HR-QOL (ß = 0.49, p < 0.001) over processing speed (p > 0.05). CONCLUSIONS: Between two fitness measures, the physical performance test demonstrated better predictive validity in proximal and distal health outcomes. In addition to physical fitness, older adults who engage in multi-component exercise sessions regularly can improve their executive functioning, which in turn enhances their HR-QOL.

A comparison of the impact of physical exercise, cognitive training and combined intervention on spontaneous walking speed in older adults.

BACKGROUND: Spontaneous walking speed (SWS) is one of the most important indicators of health in older adults. Studies have shown benefits of physical trainings on SWS in older adults but the impact of cognitive training and multidomain interventions remains understudied. AIMS: This original study aimed at comparing the impact of aerobic/resistance exercise, computerized cognitive training and the combination of both interventions compared with active control conditions on SWS in healthy older adults. METHODS: Ninety community-dwelling older adults were randomly assigned to four different combinations composed of two active interventions: physical aerobic/resistance and cognitive dual-task trainings, and two active control conditions: stretching exercises and computer lessons. The four combinations were the following: (1) aerobic/resistance and cognitive dual task (n = 28), (2) aerobic/resistance and computer lessons (n = 21), (3) stretching exercises and cognitive dual task and (n = 23), (4) stretching exercises and computer lessons (n = 18). Training sessions were held three times/week for three months. SWS for 30 s was assessed before and after the intervention. RESULTS: Repeated-measures ANOVA showed a main effect of time and a significant three-way interaction suggesting differential improvement in SWS according to training combinations. A clinical meaningful improvement in SWS was observed in groups 1-3 (0.08-0.14 m/s; effect sizes: small to moderate) but not in the active control group 4. DISCUSSION: Results of this study suggest that aerobic/resistance exercise and computerized dual-task training are two non-pharmacological interventions by which SWS, a functional vital sign, can be clinically improved in older adults. CONCLUSION: This original study pointed out different tools to prevent functional decline in older people.

Shedding light on the effect of priority instructions during dual-task performance in younger and older adults: A fNIRS study.

Age-related differences in the ability to perform two tasks simultaneously (or dual-task) have become a major concern in aging neurosciences and have often been assessed with two distinct paradigms; the Psychological Refractory Period (PRP) and the Dual-Task (DT) paradigms. PRP studies assess participants when they give Priority to one task over the other (complete A then B), whereas in DT studies participants give Equal priority to both tasks (complete A and B). The Equal condition could be viewed as adding an executive control component to the task since the participants must spontaneously monitor attention between tasks. In the current study, we assessed the effect of priority instructions (Priority vs. Equal) on the dual-task performance and brain activity of younger (n = 16) and older adults (n = 19) with functional near infra-red spectroscopy (fNIRS). In younger adults, the Priority condition showed right-sided activation in the prefrontal cortex during DT execution. Older adults showed bilateral frontal activation, yet restrained to specific areas. They showed increased activation in DT vs. single task condition in the left dorsolateral prefrontal cortex (DLPFC) and the bilateral ventrolateral prefrontal cortex (VLPFC). In the Equal condition, the DT condition showed isolated left DLPFC and VLPFC activation in younger adults and widespread bilateral DLPFC activation in older adults. These results suggest that for both older and younger adults, priority effects are associated with distinct patterns of prefrontal activation. Age-related differences also exist in these patterns such that prefrontal activation seems to be more spread out at different sites in older adults when they are instructed to give Equal priority to both tasks.

Performances on the Montreal Cognitive Assessment Along the Cardiovascular Disease Continuum.

Cardiovascular diseases involve a continuum starting with risk factors, which can progress to coronary heart disease and eventually, to heart failure. Cognitive impairment (CI) is observed as early as cardiovascular risk factors, and in up to 50% of patients with heart failure. Because CI in cardiovascular disease is linked to poorer clinical outcomes, early detection is essential. The Montreal Cognitive Assessment (MoCA) is a screening tool widely used in clinical setting. To date, little is known about MoCA scores along the cardiovascular disease continuum. OBJECTIVE: This study compared performances of different cardiovascular disease profiles on the MoCA and its subscores. METHOD: Eighty participants (>50 years) from two studies conducted at the Montreal Heart Institute were separated into four groups: low cardiovascular risk factors (<2), high cardiovascular risk factors (>2), coronary heart disease, and stable heart failure. ANCOVAs were performed on the total score and on subscores, with sex, age, and education as covariates. RESULTS: Group differences were observed on the MoCA total score (heart failure < low cardiovascular risk), verbal fluency (heart failure < low cardiovascular risk), memory (coronary heart disease < low cardiovascular risk), and orientation (coronary heart disease < low and high cardiovascular risk) subscores. CONCLUSION: Results suggest that the MoCA, particularly verbal fluency and memory subscores, can detect cognitive changes in later stages of the cardiovascular disease continuum, such as heart failure. Detecting cognitive changes earlier on the cardiovascular disease continuum may require more in depth neuropsychological assessments.

Physical Exercise Training Effect and Mediation Through Cardiorespiratory Fitness on Dual-Task Performances Differ in Younger-Old and Older-Old Adults.

OBJECTIVE: It has often been reported that dual-task (DT) performance declines with age. Physical exercise can help improve cognition, but these improvements could depend on cognitive functions and age groups. Moreover, the mechanisms supporting this enhancement are not fully elucidated. This study investigated the impacts of physical exercise on single- and dual-task performance in younger-old (<70) and older-old (70+) adults. The study also assessed whether the training effect on cognition was mediated by improvement in cardiorespiratory fitness. METHODS: One hundred forty-three participants (65-89 years) took part in a physical exercise intervention for 3 months or were assigned to a control group. All participants completed a DT paradigm and an estimated measure of cardiorespiratory fitness. Regression models were used to test the training effect on these outcomes, and mediation analyses were used to determine whether the training-related cognitive changes were mediated by changes in cardiorespiratory fitness. RESULTS: In 70+, training predicted improved processing speed (ßc = -.33) and cardiorespiratory fitness (ßa = .26) and the effect of training on processing speed was fully mediated by change in cardiorespiratory fitness (ßab = -.12). In <70, training predicted improvement in task-set cost (ßc = -.26) and change in cardiorespiratory fitness (ßa = .30) but improvement in task-set cost was not entirely mediated by change in cardiorespiratory fitness. DISCUSSION: Results are discussed in terms of the mechanisms supporting DT performance improvement following physical exercise training in older adults.

Sex moderations in the relationship between aortic stiffness, cognition, and cerebrovascular reactivity in healthy older adults.

It is well established that sex differences exist in the manifestation of vascular diseases. Arterial stiffness (AS) has been associated with changes in cerebrovascular reactivity (CVR) and cognitive decline in aging. Specifically, older adults with increased AS show a decline on executive function (EF) tasks. Interestingly, the relationship between AS and CVR is more complex, where some studies show decreased CVR with increased AS, and others demonstrate preserved CVR despite higher AS. Here, we investigated the possible role of sex on these hemodynamic relationships. Acquisitions were completed in 48 older adults. Pseudo-continuous arterial spin labeling (pCASL) data were collected during a hypercapnia challenge. Aortic pulse wave velocity (PWV) data was acquired using cine phase contrast velocity series. Cognitive function was assessed with a comprehensive neuropsychological battery, and a composite score for EF was calculated using four cognitive tests from the neuropsychological battery. A moderation model test revealed that sex moderated the relationship between PWV and CVR and PWV and EF, but not between CVR and EF. Together, our results indicate that the relationships between central stiffness, cerebral hemodynamics and cognition are in part mediated by sex.

Synergistic Effects of Cognitive Training and Physical Exercise on Dual-Task Performance in Older Adults.

BACKGROUND: Studies report benefits of physical exercise and cognitive training to enhance cognition in older adults. However, most studies did not compare these interventions to appropriate active controls. Moreover, physical exercise and cognitive training seem to involve different mechanisms of brain plasticity, suggesting a potential synergistic effect on cognition. OBJECTIVE: This study investigated the synergistic effect of cognitive training and aerobic/resistance physical exercise on dual-task performance in older adults. Intervention effects were compared to active controls for both the cognitive and the exercise domain. METHOD: Eighty-seven older adults completed one of 4 different combinations of interventions, in which computer lessons was active control for cognitive training and stretching/toning exercise control for aerobic/resistance training: (a) cognitive dual-task training and aerobic/resistance training (COG+/AER+), (b) computer lessons and aerobic/resistance training (COG-/AER+), (c) cognitive dual-task training and stretching/toning exercises (COG+/AER-), and (d) computer lessons and stretching/toning exercises (COG-/AER-). The primary outcome was performance in an untrained transfer dual task. Stepwise backward removal regression analyses were used to predict pre- versus post-test changes in groups that have completed the dual-task training, aerobic/resistance or both interventions. RESULTS: Participation in AER+ did not predict improvement in any dual-task outcomes. Participation in COG+ predicted reduction in dual-task cost and participation in COG+/AER+ predicted reduction in task-set cost. DISCUSSION: Results suggest that the combination of cognitive and physical training protocols exerted a synergistic effect on task-set cost which reflects the cost of maintaining multiple response alternatives, whereas cognitive training specifically improved dual-task cost, which reflects the ability of synchronizing concurrent tasks.

Higher cardiovascular fitness level is associated with lower cerebrovascular reactivity and perfusion in healthy older adults.

Aging is accompanied by vascular and structural changes in the brain, which include decreased grey matter volume (GMV), cerebral blood flow (CBF), and cerebrovascular reactivity (CVR). Enhanced fitness in aging has been related to preservation of GMV and CBF, and in some cases CVR, although there are contradictory relationships reported between CVR and fitness. To gain a better understanding of the complex interplay between fitness and GMV, CBF and CVR, the present study assessed these factors concurrently. Data from 50 participants, aged 55 to 72, were used to derive GMV, CBF, CVR and VO2peak. Results revealed that lower CVR was associated with higher VO2peak throughout large areas of the cerebral cortex. Within these regions lower fitness was associated with higher CBF and a faster hemodynamic response to hypercapnia. Overall, our results indicate that the relationships between age, fitness, cerebral health and cerebral hemodynamics are complex, likely involving changes in chemosensitivity and autoregulation in addition to changes in arterial stiffness. Future studies should collect other physiological outcomes in parallel with quantitative imaging, such as measures of chemosensitivity and autoregulation, to further understand the intricate effects of fitness on the aging brain, and how this may bias quantitative measures of cerebral health.

Obese but Fit: The Benefits of Fitness on Cognition in Obese Older Adults.

BACKGROUND: Obesity is associated with an accelerated cognitive decline. Aerobic fitness has a protective effect on cognition in older adults, but no study has investigated this effect in obese individuals. The present study aimed to 1) compare cognitive function in lower-fit (LoFit) and higher-fit (HiFit) obese individuals compared with nonobese individuals, and 2) examine the association between exercise variables (including hemodynamic variables) and cognitive function in obese individuals. METHODS: Fifty-four obese and 16 nonobese individuals performed a maximal cardiopulmonary exercise test (with gas exchange analysis and noninvasive hemodynamic measurement) and cognitive tests assessing short-term and working memory, processing speed, executive function, and long-term verbal memory. Obese individuals were divided into 2 groups according to their median aerobic fitness divided by lean body mass to form a group of LoFit obese (n = 27) and a group of HiFit obese (n = 27) individuals. RESULTS: A total of 14 nonobese individuals and 49 obese individuals were included in the final analysis (HiFit: n = 26, LoFit: n = 23). Compared with LoFit obese, HiFit obese participants had greater performances in executive function (P = 0.002) and short-term memory (P = 0.02). Nonobese and HiFit obese participants showed equivalent performances in all domains of cognition. In obese individuals, aerobic fitness was the only independent predictor for short-term memory (R2 = 0.24; P < 0.001), working memory (R2 = 0.16; P = 0.02), processing speed (R2 = 0.22; P = 0.01), and executive function (R2 = 0.49; P = 0.003), but not for long-term verbal memory (R2 = 0.15; P = 0.26). CONCLUSIONS: HiFit obese individuals showed greater short-term memory and executive function performances compared with LoFit obese individuals, suggesting that aerobic fitness could help preserve cognitive function despite the presence of obesity.

Arterial stiffness cut-off value and white matter integrity in the elderly.

OBJECTIVE: Central artery stiffness is a confirmed predictor of cardiovascular health status that has been consistently associated with cognitive dysfunction and dementia. The European Society of Hypertension has established a threshold of arterial stiffness above which a cardiovascular event is likely to occur. However, the threshold at which arterial stiffness alters brain integrity has never been established. METHODS: The aim of this study is to determine the arterial stiffness cut-off value at which there is an impact on the white matter microstructure. This study has been conducted with 53 cognitively elderly without dementia. The integrity of the white matter was assessed using diffusion tensor metrics. Central artery stiffness was evaluated by measuring the carotid-femoral pulse wave velocity (cfPWV). The statistical analyses included 4 regions previously denoted vulnerable to increased central arterial stiffness (the corpus callosum, the internal capsule, the corona radiata and the superior longitudinal fasciculus). RESULTS: The results of this study call into question the threshold value of 10 m/s cfPWV established by the European Society of Hypertension to classify patients in neuro-cardiovascular risk groups. Our results suggest that the cfPWV threshold value would be approximately 8.5 m/s when the microstructure of the white matter is taken as a basis for comparison. CONCLUSIONS: Adjustment of the cfPWV value may be necessary for a more accurate distinction between lower and higher risk group of patients for white matter microstructural injury related to arterial stiffness. Targeting the highest risk group for prevention methods may, in turn, help preserve brain health and cognitive functions.

Investigating dose-response effects of multimodal exercise programs on health-related quality of life in older adults.

BACKGROUND: Older adults are at risk of multiple chronic diseases, most of which could be prevented by engaging in regular physical activity. Frailty is a state of increased vulnerability to diseases. Worsening symptoms of frailty, such as decrease in physical functionality, can compromise health-related quality of life (HR-QOL). Previous findings suggest that frailty moderates the relationship between physical activity and HR-QOL, yet intervention findings are limited, particularly in dose-response analyses. Hence, this study was conducted to test if lower-dose physical activity (120 minutes/week) would provide the same benefits in health outcomes (physical functionality and HR-QOL) as higher-dose physical activity (180 minutes/week). METHODS: Participants (n=110) were older adults comprising higher-dose, lower-dose, and control groups who were combined from recent randomized controlled trials. Experimental groups participated in a multimodal exercise program in a supervised laboratory setting for 12 weeks. RESULTS: The higher-dose group showed a significant improvement in physical functionality (ß=0.23, P=0.03) and in overall HR-QOL (ß=0.44, P=0.001) including its subcategories over the control group. A group × frailty interaction revealed that frail individuals significantly improved in capacity HR-QOL when they exercised at a higher dose (F (1, 49)=4.57, P=0.038). CONCLUSION: This study identifies a positive, predictive relationship between exercise duration and health outcomes (HR-QOL dimensions and frailty) among older adults. Frail individuals in the higher-dose group demonstrated significant recovery of capacity HR-QOL, thus reflecting improvement in their daily activities.

Diurnal blood pressure loads are associated with lower cognitive performances in controlled-hypertensive elderly individuals.

INTRODUCTION: Hypertension in midlife adults is associated with cognitive decline later in life. In individuals treated for hypertension, blood pressure (BP) loads have been associated with end organ damages. This study examines whether BP load inversely correlates with performance in cognitive tasks in normotensive or controlled hypertensive (CHT) individuals. METHODS: Participants between 60 and 75 years old were divided into normotensive participants who did not receive antihypertensive treatment (n = 49) and CHT patients (n = 28). They were evaluated for BP using ambulatory blood pressure monitoring and cognitive functions with tests assessing cognitive flexibility, working and episodic memory, and processing speed. RESULTS: Analysis of covariance between normotensive and CHT participants revealed lower cognitive performances on immediate and delayed recall and total number of words of the Rey Auditory Verbal Learning Test (P < 0.001). Spearman's correlations between BP loads and cognitive performances revealed inversed associations between diurnal systolic (SBP) loads and performances on the Trail Making Test Part B (TMTB) (P = 0.009), the TMTB-TMT Part A (P = 0.013), the Switching Cost of the color-word interference test (P = 0.020) and the Digit-Symbol Substitution Score tests (P = 0.018) in CHT. Diurnal diastolic (DBP) loads were inversely correlated to the TMTB (P = 0.014) and TMTB-TMT Part A (P = 0.006). In normotensive subjects, diurnal SBP loads were associated with the delayed recall of the Rey Auditory Verbal Learning Test (P = 0.031) and to the three components of the digit span (P < 0.05). CONCLUSION: Diurnal BP loads are associated with lower cognitive performances in CHT individuals. These results suggest a lowering of target levels of diurnal BPs and/or its variability.

Does Combined Physical and Cognitive Training Improve Dual-Task Balance and Gait Outcomes in Sedentary Older Adults?

Everyday activities like walking and talking can put an older adult at risk for a fall if they have difficulty dividing their attention between motor and cognitive tasks. Training studies have demonstrated that both cognitive and physical training regimens can improve motor and cognitive task performance. Few studies have examined the benefits of combined training (cognitive and physical) and whether or not this type of combined training would transfer to walking or balancing dual-tasks. This study examines the dual-task benefits of combined training in a sample of sedentary older adults. Seventy-two older adults (≥60 years) were randomly assigned to one of four training groups: Aerobic + Cognitive training (CT), Aerobic + Computer lessons (CL), Stretch + CT and Stretch + CL. It was expected that the Aerobic + CT group would demonstrate the largest benefits and that the active placebo control (Stretch + CL) would show the least benefits after training. Walking and standing balance were paired with an auditory n-back with two levels of difficulty (0- and 1-back). Dual-task walking and balance were assessed with: walk speed (m/s), cognitive accuracy (% correct) and several mediolateral sway measures for pre- to post-test improvements. All groups demonstrated improvements in walk speed from pre- (M = 1.33 m/s) to post-test (M = 1.42 m/s, p < 0.001) and in accuracy from pre- (M = 97.57%) to post-test (M = 98.57%, p = 0.005).They also increased their walk speed in the more difficult 1-back (M = 1.38 m/s) in comparison to the 0-back (M = 1.36 m/s, p < 0.001) but reduced their accuracy in the 1-back (M = 96.39%) in comparison to the 0-back (M = 99.92%, p < 0.001). Three out of the five mediolateral sway variables (Peak, SD, RMS) demonstrated significant reductions in sway from pre to post test (p-values < 0.05). With the exception of a group difference between Aerobic + CT and Stretch + CT in accuracy, there were no significant group differences after training. Results suggest that there can be dual-task benefits from training but that in this sedentary sample Aerobic + CT training was not more beneficial than other types of combined training.

Effects of combined physical and cognitive training on fitness and neuropsychological outcomes in healthy older adults.

PURPOSE: Physical exercise and cognitive training have been shown to enhance cognition among older adults. However, few studies have looked at the potential synergetic effects of combining physical and cognitive training in a single study. Prior trials on combined training have led to interesting yet equivocal results. The aim of this study was to examine the effects of combined physical and cognitive interventions on physical fitness and neuropsychological performance in healthy older adults. METHODS: Seventy-six participants were randomly assigned to one of four training combinations using a 2×2 factorial design. The physical intervention was a mixed aerobic and resistance training program, and the cognitive intervention was a dual-task (DT) training program. Stretching and toning exercises and computer lessons were used as active control conditions. Physical and cognitive measures were collected pre- and postintervention. RESULTS: All groups showed equivalent improvements in measures of functional mobility. The aerobic-strength condition led to larger effect size in lower body strength, independently of cognitive training. All groups showed improved speed of processing and inhibition abilities, but only participants who took part in the DT training, independently of physical training, showed increased task-switching abilities. The level of functional mobility after intervention was significantly associated with task-switching abilities. CONCLUSION: Combined training did not yield synergetic effects. However, DT training did lead to transfer effects on executive performance in neuropsychological tests. Both aerobic-resistance training and stretching-toning exercises can improve functional mobility in older adults.

Higher levels of cardiovascular fitness are associated with better executive function and prefrontal oxygenation in younger and older women.

AIM: Many studies have suggested that physical exercise training improves cognition and more selectively executive functions. There is a growing interest to clarify the neurophysiological mechanisms that underlie this effect. The aim of the current study was to evaluate the neurophysiological changes in cerebral oxygenation associated with physical fitness level and executive functions. METHOD: In this study, 22 younger and 36 older women underwent a maximal graded continuous test (i.e., [Formula: see text]O2max ) in order to classify them into a fitness group (higher vs. lower fit). All participants completed neuropsychological paper and pencil testing and a computerized Stroop task (which contained executive and non-executive conditions) in which the change in prefrontal cortex oxygenation was evaluated with near infrared spectroscopy (NIRS). RESULTS: Our findings revealed a Fitness × Condition interaction (p < 0.05) such that higher fit women scored better on measures of executive functions than lower fit women. In comparison to lower fit women, higher fit women had faster reaction times in the Executive condition of the computerized Stroop task. No significant effect was observed in the non-executive condition of the test and no interactions were found with age. In measures of cerebral oxygenation (ΔHbT and ΔHbO2), we found a main effect of fitness on cerebral oxygenation during the Stroop task such that only high fit women demonstrated a significant increase in the right inferior frontal gyrus. DISCUSSION/CONCLUSION: Higher fit individuals who demonstrate better cardiorespiratory functions (as measured by [Formula: see text]O2max ) show faster reaction times and greater cerebral oxygenation in the right inferior frontal gyrus than women with lower fitness levels. The lack of interaction with age, suggests that good cardiorespiratory functions can have a positive impact on cognition, regardless of age.

Hearts and minds: linking vascular rigidity and aerobic fitness with cognitive aging.

Human aging is accompanied by both vascular and cognitive changes. Although arteries throughout the body are known to become stiffer with age, this vessel hardening is believed to start at the level of the aorta and progress to other organs, including the brain. Progression of this vascular impairment may contribute to cognitive changes that arise with a similar time course during aging. Conversely, it has been proposed that regular exercise plays a protective role, attenuating the impact of age on vascular and metabolic physiology. Here, the impact of vascular degradation in the absence of disease was investigated within 2 groups of healthy younger and older adults. Age-related changes in executive function, elasticity of the aortic arch, cardiorespiratory fitness, and cerebrovascular reactivity were quantified, as well as the association between these parameters within the older group. In the cohort studied, older adults exhibited a decline in executive functions, measured as a slower performance in a modified Stroop task (1247.90 ± 204.50 vs. 898.20 ± 211.10 ms on the inhibition and/or switching component, respectively) than younger adults. Older participants also showed higher aortic pulse wave velocity (8.98 ± 3.56 vs. 3.95 ± 0.82 m/s, respectively) and lower VO2 max (29.04 ± 6.92 vs. 42.32 ± 7.31 mL O2/kg/min, respectively) than younger adults. Within the older group, faster performance of the modified Stroop task was associated with preserved aortic elasticity (lower aortic pulse wave velocity; p = 0.046) and higher cardiorespiratory fitness (VO2 max; p = 0.036). Furthermore, VO2 max was found to be negatively associated with blood oxygenation level dependent cerebrovascular reactivity to CO2 in frontal regions involved in the task (p = 0.038) but positively associated with cerebrovascular reactivity in periventricular watershed regions and within the postcentral gyrus. Overall, the results of this study support the hypothesis that cognitive status in aging is linked to vascular health, and that preservation of vessel elasticity may be one of the key mechanisms by which physical exercise helps to alleviate cognitive aging.

Physical functioning is associated with processing speed and executive functions in community-dwelling older adults.

OBJECTIVES: The aim of this study was to examine the association between physical functioning and cardiovascular burden on the cognitive performance of community-dwelling older adults. METHOD: Ninety-three adults aged 60 and older completed a medical evaluation by a geriatrician, performance-based physical tests, and neuropsychological assessments. Cognitive composite scores (memory, speed, and executive) as well as a physical functioning score were created by averaging standardized z-scores of selected tests. A cardiovascular burden index was also computed by totalling the number of cardiovascular risk factors and diseases. RESULTS: Multiple hierarchical regression analyses reveal that higher level of physical functioning was significantly associated with greater processing speed and better executive functions but was not associated with memory performance. These relations were independent of age, sex, and level of education. Cardiovascular burden was not significantly associated with any cognitive domain. DISCUSSION: These results suggest that cognition is related to simple performance-based physical tests and highlight the importance of intervention studies aimed at enhancing cognitive and physical functioning in older adults.

Age dependence of hemodynamic response characteristics in human functional magnetic resonance imaging.

Functional magnetic resonance imaging (fMRI) studies of cognitive aging have generally compared the amplitude and extent of blood oxygen level-dependent (BOLD) signal increases evoked by a task in older and younger groups. BOLD is thus used as a direct index of neuronal activation and it is assumed that the relationship between neuronal activity and the hemodynamic response is unchanged across the lifespan. However, even in healthy aging, differences in vascular and metabolic function have been observed that could affect the coupling between neuronal activity and the BOLD signal. Here we use a calibrated fMRI method to explore vascular and metabolic changes that might bias such BOLD comparisons. Though BOLD signal changes evoked by a cognitive task were found to be similar between a group of younger and older adults (e.g., 0.50 ± 0.04% vs. 0.50 ± 0.05% in right frontal areas), comparison of BOLD and arterial spin labelling (ASL) responses elicited in the same set of structures by a controlled global hypercapnic manipulation revealed significant differences between the 2 groups. Older adults were found to have lower responses in BOLD and flow responses to hypercapnia (e.g., 1.48 ± 0.07% vs. 1.01 ± 0.06% over gray matter for BOLD and 24.92 ± 1.37% vs. 20.67 ± 2.58% for blood flow), and a generally lower maximal BOLD response M (5.76 ± 0.2% vs. 5.00 ± 0.3%). This suggests that a given BOLD response in the elderly might represent a larger change in neuronal activity than the same BOLD response in a younger cohort. The results of this study highlight the importance of ancillary measures such as ASL for the correct interpretation of BOLD responses when fMRI responses are compared across populations who might exhibit differences in vascular physiology.