Background
Exercise has the potential to reduce cognitive decline in people with Down syndrome by maximising their cognitive function. The aim of the study was to determine the effect of regular exercise on cognitive functioning in young people with Down syndrome.
Method
People with Down syndrome were eligible if aged between 13 and 35 years and enrolled to participate in an exercise programme (called FitSkills). The intervention was a 12‐week community‐based exercise programme completed with a student mentor. Outcomes were assessed before (week 0) and immediately after (week 13) the intervention. Executive functioning (planning, response inhibition, attention shifting) was assessed using Tower of London, Sustained Attention to Response Task, CANTAB Intra‐extra Dimensional Set Shift Test, Cognitive Scale for Down Syndrome, and Behaviour Rating Inventory of Executive Function (BRIEF). Working memory was assessed using the CANTAB Paired Associates Learning task, and information processing speed was assessed using the Motor Screening Task. Outcomes were analysed using ANCOVA with the baseline measure as the covariate.
Results
Twenty participants (9 women; mean age 23.6 ± 6.6 years) enrolled. Between‐group differences, in favour of the experimental group, were found for the global executive composite score of the BRIEF (mean difference −4.77 units, 95% CI −9.30 to −0.25). There were no between group differences for any other outcome measured.
Conclusion
Participation in a 12‐week exercise programme was effective in improving everyday executive functions in young people with Down syndrome. These preliminary findings need to be confirmed in future randomised controlled trials of community‐based exercise with larger sample sizes.
Meta-regression is often used to form hypotheses about what is associated with heterogeneity in a meta-analysis and to estimate the extent to which effects can vary between cohorts and other distinguishing factors. However, study-level variables, called moderators, that are available and used in the meta-regression analysis will rarely explain all of the heterogeneity. Therefore, measuring and trying to understand residual heterogeneity is still important in a meta-regression, although it is not clear how some heterogeneity measures should be used in the meta-regression context. The coefficient of variation, and its variants, are useful measures of relative heterogeneity. We consider these measures in the context of meta-regression which allows researchers to investigate heterogeneity at different levels of the moderator and also average relative heterogeneity overall. We also provide CIs for the measures and our simulation studies show that these intervals have good coverage properties. We recommend that these measures and corresponding intervals could provide useful insights into moderators that may be contributing to the presence of heterogeneity in a meta-analysis and lead to a better understanding of estimated mean effects.
Estimation of the four generalized lambda distribution parameters is not straightforward, and available estimators that perform best have large computation times. In this paper, we introduce a simple two-step estimator of the parameters that is comparatively very quick to compute and performs well when compared with other methods. This computational efficiency makes the use of bootstrapping to obtain interval estimators for the parameters possible. Simulations are used to assess the performance of the new estimators and applications to several data sets are included.
IntroductionPreliminary evidence suggests that progressive resistance training may be beneficial for people with Prader-Willi Syndrome (PWS), a rare genetic condition that results in muscle weakness and low muscle tone.To establish whether community-based progressive resistance training is effective in improving the muscle strength of people with PWS; to determine cost-effectiveness; and, to complete a process evaluation assessing intervention fidelity, exploring mechanisms of impact, understanding participant experiences and identifying contextual factors affecting implementation.Methods and analysisA multisite, randomised controlled trial will be completed. Sixty participants with PWS will be randomised to receive either progressive resistance training (experimental) or non-progressive exercise (placebo control). Participants will be aged 13 to 60 years, be able to follow simple instructions in English and have no contraindications to performing progressive resistance training. The experimental group will complete progressive resistance training two times weekly for 24 weeks supervised by an exercise professional at a community gym. The control group will receive all aspects of the intervention except progressive overload. Outcomes will be assessed at week 25 (primary endpoint) and week 52 by a blinded assessor. The primary outcome is muscle strength assessed using one repetition maximum for upper limb and lower limb. Secondary outcomes are muscle mass, functional strength, physical activity, community participation, health-related quality of life and behaviour. Health economic analysis will evaluate cost-effectiveness. Process evaluation will assess safety and intervention fidelity, investigate mechanism of impact, explore participant experiences and identify contextual factors affecting implementation. Data collection commenced in February 2020 and will conclude in September 2023.Ethics and disseminationEthical approval was obtained from The Royal Children’s Hospital Human Research Ethics Committee (HREC/50874/RCHM-2019) under the National Mutual Acceptance initiative. Research governance approvals were obtained from five clinical sites. Results will be disseminated through published manuscripts, conference presentations, public seminars and practical resources for stakeholder groups.Trial registration numberACTRN12620000416998; Australian and New Zealand Clinical Trial Registry.
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