755 research outputs found

    The Practitioner\u27s Corner: An exploration of municipal active living charter development and advocacy

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    Background: Numerous municipal active living-­‐related charters have been adopted to promote physical activity in Canada throughout the past decade. Despite this trend, there are few published critical examinations of the process through which charters are developed and used. Purpose: Thus, the purpose of this study was to establish greater understanding of active living charter development and advocacy. Methods: Semi-­‐structured interviews were conducted with eight primary contributors to different active living-­‐related charters across Ontario, Canada. Interview questions explored participants’ experiences developing and advocating for an active living charter. Interviews were analyzed using open, axial, and selective coding. Results and Conclusions: Participants consistently described a process whereby an impetus triggered the development of a charter, which was subsequently adopted by regional or municipal council. Continued advocacy to develop awareness of the charter and to promote desired outcomes in the community was valued and the capacity of the working group as well as the local political context played pivotal roles in determining how the charter was implemented. Outcomes were, however, only objectively evaluated in one case that was described – evaluation being a process that many participants thought was omitted in regard to their own charter. This work provides practical guidance for health professionals developing regional active living charters as a component of broader advocacy efforts

    Physical Activity in Individuals with Autism Spectrum Disorders (ASD): A Review

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    Current recommendations indicate that children and youth ages 5–17 should participate in 60 min and adults in 150 min of moderate-to-vigorous physical activity daily. Research suggests that physical activity levels of individuals with autism spectrum disorder (ASD) are lower than typically developing and developed peers. Despite evidence for PA decreasing negative behaviors and promoting positive behaviors, individuals with ASD may be less motivated and less likely to participate. Individuals with ASD may be more likely to be overweight or obese than their typically developing counterparts as a result of decreased activity levels. Conflicting findings regarding PA levels in individuals with ASD have been reported. Given mixed evidence, further inquiry is warranted. The present chapter provides a review of literature pertaining to PA in individuals with ASD. Four databases were searched. Predetermined search terms and inclusion/exclusion criteria were clearly outlined to identify relevant articles which were then critically appraised. This research provides a greater understanding of the status of PA participation of individuals with ASD

    Aberrant Neuronal Dynamics during Working Memory Operations in the Aging HIV-Infected Brain

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    Impairments in working memory are among the most prevalent features of HIV-associated neurocognitive disorders (HAND), yet their origins are unknown, with some studies arguing that encoding operations are disturbed and others supporting deficits in memory maintenance. The current investigation directly addresses this issue by using a dynamic mapping approach to identify when and where processing in working memory circuits degrades. HIV-infected older adults and a demographically-matched group of uninfected controls performed a verbal working memory task during magnetoencephalography (MEG). Significant oscillatory neural responses were imaged using a beamforming approach to illuminate the spatiotemporal dynamics of neuronal activity. HIV-infected patients were significantly less accurate on the working memory task and their neuronal dynamics indicated that encoding operations were preserved, while memory maintenance processes were abnormal. Specifically, no group differences were detected during the encoding period, yet dysfunction in occipital, fronto-temporal, hippocampal, and cerebellar cortices emerged during memory maintenance. In addition, task performance in the controls covaried with occipital alpha synchronization and activity in right prefrontal cortices. In conclusion, working memory impairments are common and significantly impact the daily functioning and independence of HIV-infected patients. These impairments likely reflect deficits in the maintenance of memory representations, not failures to adequately encode stimuli

    Aberrant Neuronal Dynamics during Working Memory Operations in the Aging HIV-Infected Brain.

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    Impairments in working memory are among the most prevalent features of HIV-associated neurocognitive disorders (HAND), yet their origins are unknown, with some studies arguing that encoding operations are disturbed and others supporting deficits in memory maintenance. The current investigation directly addresses this issue by using a dynamic mapping approach to identify when and where processing in working memory circuits degrades. HIV-infected older adults and a demographically-matched group of uninfected controls performed a verbal working memory task during magnetoencephalography (MEG). Significant oscillatory neural responses were imaged using a beamforming approach to illuminate the spatiotemporal dynamics of neuronal activity. HIV-infected patients were significantly less accurate on the working memory task and their neuronal dynamics indicated that encoding operations were preserved, while memory maintenance processes were abnormal. Specifically, no group differences were detected during the encoding period, yet dysfunction in occipital, fronto-temporal, hippocampal, and cerebellar cortices emerged during memory maintenance. In addition, task performance in the controls covaried with occipital alpha synchronization and activity in right prefrontal cortices. In conclusion, working memory impairments are common and significantly impact the daily functioning and independence of HIV-infected patients. These impairments likely reflect deficits in the maintenance of memory representations, not failures to adequately encode stimuli

    Habitual physical activity (HPA) as a factor in sustained executive function in Alzheimer-type dementia: a cohort study

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    Evidence from studies on healthy older adults and mild cognitive impairment (MCI) populations suggests that physical activity interventions have a positive effect on executive function. In this study, we consider whether HPA is positively associated with executive function in Alzheimer's disease (AD). Eighty-two participants with a diagnosis of mild to moderate AD completed six measures of executive function. Objective measures of physical status were taken. In addition, informants completed questionnaires on the participants’ HPA and other lifestyle factors. A composite measure of executive function was the primary outcome. A multistage multiple regression was used to determine how much variance HPA accounted for. The final model comprised disease severity, cognitive reserve, cognitive activities, neuropsychiatric status and HPA status. The final model accounted for a total of 57% of the variance of executive performance, of which HPA itself accounted for 8% of the variance. HPA status is associated executive performance in an AD population even after controlling for key covariates. The findings encourage clinicians to recommend HPA and its cognitive benefits to AD patients and their carers

    Functional Brain Abnormalities During Finger-Tapping in HIV-Infected Older Adults: A Magnetoencephalography Study

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    Despite the availability of combination antiretroviral therapy, at least mild cognitive dysfunction is commonly observed in HIV-infected patients, with an estimated prevalence of 35-70%. Neuropsychological studies of these HIV-associated neurocognitive disorders (HAND) have documented aberrations across a broad range of functional domains, although the basic pathophysiology remains unresolved. Some of the most common findings have been deficits in fine motor control and reduced psychomotor speed, but to date no neuroimaging studies have evaluated basic motor control in HAND. In this study, we used magnetoencephalography (MEG) to evaluate the neurophysiological processes that underlie motor planning in older HIV-infected adults and a matched, uninfected control group. MEG is a noninvasive and direct measure of neural activity with good spatiotemporal precision. During the MEG recording, participants fixated on a central crosshair and performed a finger-tapping task with the dominant hand. All MEG data was corrected for head movements, preprocessed, and imaged in the time-frequency domain using beamforming methodology. All analyses focused on the pre-movement beta desynchronization, which is known to be an index of movement planning. Our results demonstrated that HIV-1-infected patients have deficient beta desynchronization relative to controls within the left/right precentral gyri, and the supplementary motor area. In contrast, HIV-infected persons showed abnormally strong beta responses compared to controls in the right dorsolateral prefrontal cortex and medial prefrontal areas. In addition, the amplitude of beta activity in the primary and supplementary motor areas correlated with scores on the Grooved Pegboard test in HIV-infected adults. These results demonstrate that primary motor and sensory regions may be particularly vulnerable to HIV-associated damage, and that prefrontal cortices may serve a compensatory role in maintaining motor performance levels in infected patients

    Abnormal MEG Oscillatory Activity during Visual Processing in the Prefrontal Cortices and Frontal Eye-Fields of the Aging HIV Brain

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    ObjectiveShortly after infection, HIV enters the brain and causes widespread inflammation and neuronal damage, which ultimately leads to neuropsychological impairments. Despite a large body of neuroscience and imaging studies, the pathophysiology of these HIV-associated neurocognitive disorders (HAND) remains unresolved. Previous neuroimaging studies have shown greater activation in HIV-infected patients during strenuous tasks in frontal and parietal cortices, and less activation in the primary sensory cortices during rest and sensory stimulation.MethodsHigh-density magnetoencephalography (MEG) was utilized to evaluate the basic neurophysiology underlying attentive, visual processing in older HIV-infected adults and a matched non-infected control group. Unlike other neuroimaging methods, MEG is a direct measure of neural activity that is not tied to brain metabolism or hemodynamic responses. During MEG, participants fixated on a centrally-presented crosshair while intermittent visual stimulation appeared in their top-right visual-field quadrant. All MEG data was imaged in the time-frequency domain using beamforming.ResultsUninfected controls had increased neuronal synchronization in the 6–12 Hz range within the right dorsolateral prefrontal cortex, right frontal eye-fields, and the posterior cingulate. Conversely, HIV-infected patients exhibited decreased synchrony in these same neural regions, and the magnitude of these decreases was correlated with neuropsychological performance in several cortical association regions.ConclusionsMEG-based imaging holds potential as a noninvasive biomarker for HIV-related neuronal dysfunction, and may help identify patients who have or may develop HAND. Reduced synchronization of neural populations in the association cortices was strongly linked to cognitive dysfunction, and likely reflects the impact of HIV on neuronal and neuropsychological health

    Decreased MEG beta oscillations in HIV-infected older adults during the resting state

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    The introduction of combination antiretroviral therapy significantly reduced the prevalence of the most severe form of HIV-associated neurocognitive disorders (HAND). Despite this decline, 35–70% of HIV-infected patients continue to develop mild motor and cognitive impairments. Although neuropsychological studies have shown that HAND affects a wide array of cognitive functions, a formal diagnosis is still based on the exclusion of opportunistic infections and other common ailments, as no specific tests or biomarkers are currently available. In this study, we used magnetoencephalography (MEG) to measure neural activity during the resting-state in 15 HIV-infected older patients and a demographically-matched group of 15 uninfected controls. MEG is a noninvasive and direct measure of neural activity with excellent spatiotemporal resolution. All MEG data were coregistered to structural MRI, corrected for head motion, fitted to a regional-level source model, and subjected to spectral analyses to quantify population-level neural oscillatory activity. We found that HIV-infected persons exhibited decreased beta oscillations in the supplementary motor area bilaterally, paracentral lobule, posterior cingulate, and bilateral regions of the superior parietal lobule relative to healthy controls. Beta oscillations in the posterior cingulate, a critical component of the default mode network, were also positively correlated with patient scores on the memory recall aspect of the Hopkins Verbal Learning Test-Revised. These results demonstrate that chronic HIV infection does not uniformly disturb cortical function, and that neuronal populations in dorso-medial motor and parietal cortices are especially affected. These findings also suggest that resting-state MEG recordings may hold significant promise as a functional biomarker for identifying HAND and monitoring disease progression
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