Exercise engagement drives changes in cognition and cardiorespiratory fitness after 8 weeks of aerobic training in sedentary aging adults at risk of cognitive decline

BackgroundWith our aging population, many individuals are at risk of developing age-related cognitive decline. Physical exercise has been demonstrated to enhance cognitive performance in aging adults. This study examined the effects of 8 weeks of aerobic exercise on cognitive performance and cardiorespiratory fitness in sedentary aging adults at risk for cognitive decline.MethodsFifty-two participants (age 62.9 ± 6.8, 76.9% female) engaged in eight weeks of moderate-to high-intensity exercise (19 in-person, 33 remotely). Global cognition was measured by the Repeatable Battery for the Assessment of Neuropsychological Status, the Delis-Kaplan Executive Function System, and the Digit Span subtest of the Wechsler Adult Intelligence Scale (WAIS) Fourth Edition. Cardiorespiratory fitness was measured via heart rate recovery at minute 1 (HRR1) and 2 (HRR2), and exercise engagement (defined as percent of total exercise time spent in the prescribed heart rate zone). We measured pre and post changes using paired t-tests and mixed effects models, and investigated the association between cardiorespiratory and cognitive performance using multiple regression models. Cohen's d were calculated to estimate effect sizes.ResultsOverall, 63.4 % of participants demonstrated high engagement (≥ 70% total exercise time spent in the prescribed heart rate zone). There were significant pre-post improvements in verbal fluency and verbal memory, and a significant decrement in working memory, but these were associated with small effect sizes (Cohen's d <0.5). Concerning cardiorespiratory fitness, there was a pre-to-post significant improvement in HRR1 (p = 0.01, d = 0.30) and HRR2 (p < 0.001, d = 0.50). Multiple regressions revealed significant associations between cardiorespiratory and cognitive performance, but all were associated with small effect sizes (Cohen's d < 0.5). Interestingly, there were significant between-group differences in exercise engagement (all p < 0.001), with remote participants demonstrating greater exercise engagement than in-person participants.ConclusionImprovements in cognition and cardiorespiratory fitness were observed after 8 weeks of moderate to high-intensity exercise in aging adults. These results suggest that committing to a regular exercise regimen, even for a brief two-month period, can promote improvements in both cardiorespiratory fitness and cognitive performance, and that improvements are driven by exercise engagement

Cognitive Motor Interference in Adults: Insights from Dual-Task Walking Assessments and an Assessment of Synaptic Plasticity

As our population of aging adults continues to grow, finding ways to maintain health-span with our increased lifespan is essential. Central to health span is maintenance of mobility and cognitive function. In addition to maintaining these functions, it is essential to understand indicators of optimal health in domains of mobility and cognition. In aging adults, deficits in mobility and cognition coincide. Specifically, walking and cognitive function are highly intertwined. Even in early stages of disease onset in mild cognitive impairment and dementia, decrements in walking are observable.1,2 Declines in gait speed have also been shown to be predictive of future cognitive decline, up to 12 years prior to disease onset.ADDIN CSL_CITATION{"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1001/archneurol.2010.159","ISSN":"1538-3687","PMID":"20697049","abstract":"OBJECTIVESTo compare the trajectory of motor decline, as measured by gait speed andfinger-tapping speed, between elderly people who developed mild cognitiveimpairment (MCI) and those who remained cognitively intact. We also sought todetermine the approximate time at which the decline in motor functionaccelerated in persons who developed MCI. DESIGN Longitudinal cohort study.PARTICIPANTS Participants were 204 healthy seniors (57.8% women) from theOregon Brain Aging Study evaluated for up to 20 years using annual neurologic,neuropsychological, and motor examinations. MAIN OUTCOME MEASURES The patternof motor decline with aging was compared using a mixed-effects model with aninteraction term for age and a clinical diagnosis of MCI. The time beforediagnosis of MCI, when the change in gait or finger-tapping speed accelerates,was assessed using a mixed-effects model with a change point for men and women,separately and combined, who developed MCI. RESULTS The rates of change, withaging, in gait speed (P 3","plainTextFormattedCitation":"3","previouslyFormattedCitation":"3"},"properties":{"noteIndex":0},"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"}3The performance of dual-task (DT) walking, walking while performing a secondary cognitive task, can give simultaneous insights into cognitive and motor function in aging adults. Current research is attempting to utilize DT walking assessments as a way to increase the stress of the walking to improve prediction of future neurodegenerative diseases.4&nbsp;While there are longitudinal studies investigated the utility of DT walking as a predictor of decline, there is still much unknown about neurobiological factors that are related to DT walking performance in aging adults.The goal of this research is to investigate how components of resiliency (cognitive and physical reserve, brain maintenance, and brain reserve) can mediate the effects of aging in the context of DT walking assessments. Experiment 1 investigates the relationship between multiple domains of cognitive and executive function, and performance of DT walking using a measure of mobility, the Timed up-and-go, and a measure of self-selected gait speed. Experiment 2 investigates the relationship of neuroplasticity, a component of brain maintenance,&nbsp; and DT walking performance. Finally, to model altered brain reserve, Experiment 3 investigates the differences in DT performance between healthy aging adults and individuals who have suffered a stroke, using two distinct walking tasks.</p

Exercise for Brain Health: An Investigation into the Underlying Mechanisms Guided by Dose

There is a strong link between the practice of regular physical exercise and maintenance of cognitive brain health. Animal and human studies have shown that exercise exerts positive effects on cognition through a variety of mechanisms, such as changes in brain volume and connectivity, cerebral perfusion, synaptic plasticity, neurogenesis, and regulation of trophic factors. However, much of this data has been conducted in young humans and animals, raising questions regarding the generalizability of these findings to aging adults. Furthermore, it is not clear at which doses these effects might take place, and if effects would differ with varying exercise modes (such as aerobic, resistance training, combinations, or other). The purpose of this review is to summarize the evidence on the effects of exercise interventions on various mechanisms believed to support cognitive improvements: cerebral perfusion, synaptic neuroplasticity, brain volume and connectivity, neurogenesis, and regulation of trophic factors. We synthesized the findings according to exposure to exercise (short- [1 day-16 weeks], medium- [24-40 weeks], and long-term exercise [52 weeks and beyond]) and have limited our discussion of dose effects to studies in aging adults and aged animals (when human data was not available)

Abstract TP385: A Mobile-Friendly Website to Reduce Stroke Caregiver Burden: A Qualitative and Pilot Study

Background: Researchers estimate the prevalence of stroke caregiver burden to be 25-50%. Currently, there are no feasible, user-centered interventions in practice to improve stroke caregiver burden. Objectives: To refine the Stroke Caregiver Support System, a mobile-friendly website, with feedback from structured interviews, and to test the feasibility of the Stroke Caregiver Support System with a small pilot study. Methods: We employed a user-centered design framework for the development of our intervention, which includes 9 topical modules with brief introductory videos and curated resources from publically available sources. To refine the intervention, we used feedback from structured qualitative interviews with stroke caregivers for each aspect of the intervention. We then enrolled 8 stroke caregivers in a pilot study to measure baseline caregiver burden and depressive symptoms and test the feasibility of the intervention. All descriptive statistics were computed using SAS 9.4. Results: In structured qualitative interviews (N=4), stroke caregivers were aged 53-59 years; 3 of these caregivers were daughters of stroke survivors, and 2 identified as Hispanic/Latino. The main criticisms of the website included: a) low volume on videos, b) the need for more specific information for the physical challenges of caregiving, and c) the need to improve the language to make it less “scientific.” Generally, caregivers found the modules relevant and the content useful. The pilot study included 8 caregivers (mean [SD] age = 45 [17]), including 7 females, 5 who identified as Hispanic/Latino, and 6 who had a college education or greater. These caregivers had a mean (SD) Zarit burden score of 17 (8) and mean (SD) 10-item CES-D score of 14 (5). In general, caregivers found the website content and organization helpful, but the design and layout needed improvement. Caregivers emphasized that each “caregiver journey” was different, so tailored intervention is needed. Conclusions: Caregivers provided important feedback for the design of this mobile-friendly, educational intervention. Post-intervention measures will give insight into the feasibility and potential efficacy of the Stroke Caregiver Support System to attenuate caregiver burden

Efficacy of mechanisms of neuroplasticity after a stroke

Background: The sequelae of stoke, including the loss and recovery of function, are strongly linked to the mechanisms of neuroplasticity. Rehabilitation and non-invasive brain stimulation (NIBS) paradigms have shown promise in modulating corticomotor neuroplasticity to promote functional recovery in individuals post-stroke. However, an important limitation to these approaches is that while stroke recovery depends on the mechanisms of neuroplasticity, those mechanisms may themselves be altered by a stroke. Objective: Compare Transcranial Magnetic Stimulation (TMS)-based assessments of efficacy of mechanism of neuroplasticity between individuals post-stroke and age-matched controls. Methods: Thirty-two participants (16 post-stroke, 16 control) underwent an assessment of mechanisms of neuroplasticity, measured by the change in amplitude of motor evoked potentials elicited by single-pulse TMS 10–20 minutes following intermittent theta-burst stimulation (iTBS), and dual-task effect (DTE) reflecting cognitive-motor interference (CMI). In stroke participants, we further collected: time since stroke, stroke type, location, and Stroke Impact Scale 16 (SIS-16). Results: Although there was no between-group difference in the efficacy of TMS-iTBS neuroplasticity mechanism (p = 0.61, η2 = 0.01), the stroke group did not exhibit the expected facilitation to TMS-iTBS (p = 0.60, η2 = 0.04) that was shown in the control group (p = 0.016, η2 = 0.18). Sub-cohort analysis showed a trend toward a difference between those in the late-stage post-stroke and the control group (p = 0.07, η2 = 0.12). Within the post-stroke group, we found significant relationships between TMS-iTBS neuroplasticity and time since stroke onset, physical function (SIS-16), and CMI (all rs > |0.53| and p-values < 0.05). Conclusions: In this proof-of-principle study, our findings suggested altered mechanisms of neuroplasticity in post-stroke patients which were dependent on time since stroke and related to motor function. TMS-iTBS neuroplasticity assessment and its relationship with clinical functional measures suggest that TMS may be a useful tool to study post-stroke recovery. Due to insufficient statistical power and high variability of the data, generalization of the findings will require replication of the results in a larger, better-characterized cohort

Harnessing Neuroplasticity to Promote Brain Health in Aging Adults: Protocol for the MOVE-Cog Intervention Study

BackgroundExtensive evidence supports a link between aerobic exercise and cognitive improvements in aging adults. A major limitation with existing research is the high variability in cognitive response to exercise. Our incomplete understanding of the mechanisms that influence this variability and the low adherence to exercise are critical knowledge gaps and major barriers for the systematic implementation of exercise for promoting cognitive health in aging. ObjectiveWe aimed to provide an in-person and remotely delivered intervention study protocol with the main goal of informing the knowledge gap on the mechanistic action of exercise on the brain by characterizing important mechanisms of neuroplasticity, cardiorespiratory fitness response, and genetics proposed to underlie cognitive response to exercise. MethodsThis is an open-label, 2-month, interventional study protocol in neurologically healthy sedentary adults. This study was delivered fully in-person and in remote options. Participants underwent a total of 30 sessions, including the screening session, 3 pretest (baseline) assessments, 24 moderate-to-vigorous aerobic exercise sessions, and 3 posttest assessments. We recruited participants aged 55 years and above, sedentary, and cognitively healthy. Primary outcomes were neuroplasticity, cognitive function, and cardiorespiratory fitness. Secondary outcomes included genetic factors, endothelium function, functional mobility and postural control, exercise questionnaires, depression, and sleep. We also explored study feasibility, exercise adherence, technology adaptability, and compliance of both in-person and remote protocols. ResultsThe recruitment phase and data collection of this study have concluded. Results are expected to be published by the end of 2021 or in early 2022. ConclusionsThe data generated in these studies will introduce tangible parameters to guide the development of personalized exercise prescription models for maximal cognitive benefit in aging adults. Successful completion of the specific aims will enable researchers to acquire the appropriate expertise to design and conduct studies by testing personalized exercise interventions in person and remotely delivered, likely to be more effective at promoting cognitive health in aging adults. Trial RegistrationClinicalTrials.gov NCT03804528; http://clinicaltrials.gov/ct2/show/NCT03804528 International Registered Report Identifier (IRRID)RR1-10.2196/3358

Reduced motor cortex inhibition and a \u27cognitive-first\u27 prioritisation strategy for older adults during dual-tasking

It is well established that older adults are less able to perform attentionally demanding motor tasks, placing them at greater risk of accident-related injury. The primary purpose of this study was to investigate whether the interplay between prefrontal and motor cortex activity could predict such age-related performance deficits. Using a dual-task (DT) paradigm, 15 younger and 15 older adults participated in experiment 1, where brain activity was simultaneously measured using functional near infrared spectroscopy (fNIRS) and transcranial magnetic stimulation (TMS). Experiment 1 demonstrated poorer performance for the older group across a range of DTs combining visuomotor arm tracking with a secondary cognitive or motor task. Interestingly however, older adults' DT performance error was isolated to the motor component of DTs. TMS data revealed reduced motor cortex (M1) inhibition during DTs for older adults, and a trend for this correlating with poorer performance. In contrast, poorer performing younger adults showed significantly higher M1 inhibition. Experiment 2 was conducted given a high amount of movement artifact in experiment 1 fNIRS data. Using fNIRS to measure prefrontal, premotor, and motor cortex activity in an additional 15 older adults, we found no evidence of an interplay between these regions predicting DT performance. Nevertheless, performance data replicated experiment 1 in showing that DT error was isolated to motor tasks in older adults, with no significant cognitive task error. Overall, this study shows that older adults seemed to adopt a ‘cognitive-first’ prioritisation strategy during the DTs involved in our study, and that deficits in DT performance may be related to the modulation of M1 inhibitory mechanisms. We propose that clinicians advise older adults to allocate greater attention to motor tasks during activities where they may be at risk of accident-related injury

Non-invasive Brain Stimulation: Probing Intracortical Circuits and Improving Cognition in the Aging Brain

The impact of cognitive aging on brain function and structure is complex, and the relationship between aging-related structural changes and cognitive function are not fully understood. Physiological and pathological changes to the aging brain are highly variable, making it difficult to estimate a cognitive trajectory with which to monitor the conversion to cognitive decline. Beyond the information on the structural and functional consequences of cognitive aging gained from brain imaging and neuropsychological studies, non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) can enable stimulation of the human brain in vivo, offering useful insights into the functional integrity of intracortical circuits using electrophysiology and neuromodulation. TMS measurements can be used to identify and monitor changes in cortical reactivity, the integrity of inhibitory and excitatory intracortical circuits, the mechanisms of long-term potentiation (LTP)/depression-like plasticity and central cholinergic function. Repetitive TMS and tDCS can be used to modulate neuronal excitability and enhance cortical function, and thus offer a potential means to slow or reverse cognitive decline. This review will summarize and critically appraise relevant literature regarding the use of TMS and tDCS to probe cortical areas affected by the aging brain, and as potential therapeutic tools to improve cognitive function in the aging population. Challenges arising from intra-individual differences, limited reproducibility, and methodological differences will be discussed

Exercise engagement drives changes in cognition and cardiorespiratory fitness after 8 weeks of aerobic training in sedentary aging adults at risk of cognitive decline

BACKGROUND: With our aging population, many individuals are at risk of developing age-related cognitive decline. Physical exercise has been demonstrated to enhance cognitive performance in aging adults. This study examined the effects of 8 weeks of aerobic exercise on cognitive performance and cardiorespiratory fitness in sedentary aging adults at risk for cognitive decline. METHODS: Fifty-two participants (age 62.9 ± 6.8, 76.9% female) engaged in eight weeks of moderate-to high-intensity exercise (19 in-person, 33 remotely). Global cognition was measured by the Repeatable Battery for the Assessment of Neuropsychological Status, the Delis-Kaplan Executive Function System, and the Digit Span subtest of the Wechsler Adult Intelligence Scale (WAIS) Fourth Edition. Cardiorespiratory fitness was measured via heart rate recovery at minute 1 (HRR1) and 2 (HRR2), and exercise engagement (defined as percent of total exercise time spent in the prescribed heart rate zone). We measured pre and post changes using paired t-tests and mixed effects models, and investigated the association between cardiorespiratory and cognitive performance using multiple regression models. Cohen's d were calculated to estimate effect sizes. RESULTS: Overall, 63.4 % of participants demonstrated high engagement (≥ 70% total exercise time spent in the prescribed heart rate zone). There were significant pre-post improvements in verbal fluency and verbal memory, and a significant decrement in working memory, but these were associated with small effect sizes (Cohen's d <0.5). Concerning cardiorespiratory fitness, there was a pre-to-post significant improvement in HRR1 (p = 0.01, d = 0.30) and HRR2 (p < 0.001, d = 0.50). Multiple regressions revealed significant associations between cardiorespiratory and cognitive performance, but all were associated with small effect sizes (Cohen's d < 0.5). Interestingly, there were significant between-group differences in exercise engagement (all p < 0.001), with remote participants demonstrating greater exercise engagement than in-person participants. CONCLUSION: Improvements in cognition and cardiorespiratory fitness were observed after 8 weeks of moderate to high-intensity exercise in aging adults. These results suggest that committing to a regular exercise regimen, even for a brief two-month period, can promote improvements in both cardiorespiratory fitness and cognitive performance, and that improvements are driven by exercise engagement