scholarly journals Do Motoneurons Slow With Aging? A Systematic Review And Meta-Analysis With Meta-Regression

2020 ◽  
Author(s):  
Lucas B. R Orssatto ◽  
David Borg ◽  
Linda Pendrith ◽  
Anthony J. Shield ◽  
Anthony J. Blazevich ◽  
...  
Keyword(s):  
Older Adults ◽  
Motor Control ◽  
Functional Role ◽  
Meta Analysis ◽  
Force Production ◽  
Upper Body ◽  
Anatomical Location ◽  
Discharge Rates ◽  
Meta Regression ◽  
Lower Discharge

Nervous system maladaptation is linked to the loss of muscle force production and motor control with aging. However, the mechanisms specifically underpinning these muscle functional limitations remain unclear. Motoneuron discharge rates are a critical determinant of force production and strongly impact motor control; thus, lower discharge rates could underpin force and physical function losses during aging. The present meta-analysis with meta-regression summarises the findings of studies comparing motoneuron discharge rates between young and older adults and examines whether a muscle's functional role and anatomical location influences discharge rates across contraction intensities during aging. Meta-analysis revealed lower discharge rates in older compared to young adults in lower body flexor (standardised mean difference, SMD=-0.86; 95%CI: -1.20, -0.51; p<0.001) but not extensor (SMD=-0.18; 95%CI: -0.50, 0.15; p=0.29) muscles or upper body muscles (SMD=-0.79; 95%CI: -1.75, 0.18; p=0.11). Meta-regression revealed that the differences in discharge rate between young and older adults increase with contraction intensity in upper body muscles (β=-0.033, p=0.004). These findings suggest that motor function loss with aging might be partly explained by reduced motoneuron discharge rates; however, this decrease varies according to a muscle's anatomical location, functional role, and contraction intensity.

The Effect of Unsupervised Home-Based Exercise Training on Physical Functioning Outcomes in Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

2021 ◽  
pp. 109980042198943
Author(s):  
Mahdi Mahjur ◽  
Ali Asghar Norasteh
Keyword(s):  
Older Adults ◽  
Exercise Training ◽  
Randomized Controlled Trials ◽  
Physical Functioning ◽  
Meta Analysis ◽  
Upper Body ◽  
Controlled Trials ◽  
Randomized Controlled ◽  
Home Based ◽  
Body Strength

Background: Exercise training such as balance, aerobic, and resistance training is able to improve physical functioning of older adults. Delivering such exercise regimes at home without supervision may be useful for older adults because they do not have to leave their homes. Objective: This systematic review and meta-analysis of randomized controlled trials aimed to establish the effect of unsupervised home-based exercise training regimes on physical functioning (balance and muscle strength) in older adults. Data sources: PubMed, CINAHL, Medline, Google Scholar, and Scopus databases and reference lists of included investigations were searched. Study selection: Thirteen randomized controlled trials (RCTs) of exercise training impact on balance and upper body strength with concurrent control groups were included in the analysis. Results: Our analyses revealed that in older adults, unsupervised home-based various exercise training was effective in improving measures of proactive balance (mean difference (MD) = −1.37 s; 95% confidence interval (CI), −2.24, −0.51 s; p = 0.002) and balance test battery (MD: 1.80; 95% CI, 0.46, 3.14 s; p = 0.009). There were no significant differences between the experimental and control groups for upper body strength ( p > 0.05). Conclusion: Unsupervised home-based exercise training improves balance in older adults. Future investigations are needed to clarify the mechanisms underlying unsupervised home-based exercise training’s effect on this population’s physical functioning outcomes.

scholarly journals Effects of age on the identification of emotions in facial expressions: a meta-analysis

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5278 ◽  
Author(s):  
Ana R. Gonçalves ◽  
Carina Fernandes ◽  
Rita Pasion ◽  
Fernando Ferreira-Santos ◽  
Fernando Barbosa ◽  
...  
Keyword(s):  
Older Adults ◽  
Facial Expressions ◽  
Formal Education ◽  
Meta Analysis ◽  
Empirical Studies ◽  
Emotion Identification ◽  
Younger Adults ◽  
Age Related ◽  
Meta Regression ◽  
Meta Regression Analysis

Background Emotion identification is a fundamental component of social cognition. Although it is well established that a general cognitive decline occurs with advancing age, the effects of age on emotion identification is still unclear. A meta-analysis by Ruffman and colleagues (2008) explored this issue, but much research has been published since then, reporting inconsistent findings. Methods To examine age differences in the identification of facial expressions of emotion, we conducted a meta-analysis of 24 empirical studies (N = 1,033 older adults, N = 1,135 younger adults) published after 2008. Additionally, a meta-regression analysis was conducted to identify potential moderators. Results Results show that older adults less accurately identify facial expressions of anger, sadness, fear, surprise, and happiness compared to younger adults, strengthening the results obtained by Ruffman et al. (2008). However, meta-regression analyses indicate that effect sizes are moderated by sample characteristics and stimulus features. Importantly, the estimated effect size for the identification of fear and disgust increased for larger differences in the number of years of formal education between the two groups. Discussion We discuss several factors that might explain the age-related differences in emotion identification and suggest how brain changes may account for the observed pattern. Furthermore, moderator effects are interpreted and discussed.

scholarly journals A Threshold of Objectively-Assessed Daily Sedentary Time for All-cause Mortality in Older Adults: A Meta-Regression of Prospective Cohort Studies

2019 ◽  
Vol 8 (4) ◽  
pp. 564 ◽  
Author(s):  
Ku ◽  
Steptoe ◽  
Liao ◽  
Hsueh ◽  
Chen
Keyword(s):  
Older Adults ◽  
Dose Response ◽  
Sedentary Time ◽  
Meta Analysis ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Mortality Risks ◽  
Prospective Cohort Studies ◽  
All Cause Mortality ◽  
Meta Regression

Background: This meta-analysis aimed to estimate the shape of the dose-response association between objectively-assessed daily sedentary time (ST) and all-cause mortality, and to explore whether there is a threshold of ST above which there is an increase in mortality risk in older adults. Methods: Searches for prospective cohort studies providing effect estimates of daily ST (exposure) on all-cause mortality (outcome) were undertaken in five databases up to 31 March 2019. A random-effects meta-regression model was conducted to quantify the dose-response relationship between daily ST and all-cause mortality. Sensitivity analyses were also performed to test the stability of the results. Results: Our analysis of pooled data from 11 eligible studies did not reveal a consistent shape of association between ST and mortality. After excluding three studies with potential confounding bias, there was a log-linear dose-response relationship between daily ST and all-cause mortality. Overall, higher amounts of time spent in sedentary behaviors were associated with elevated mortality risks in older adults. Visual assessments of dose-response relationships based on meta-regression analyses indicated that increased mortality risks became significant when total ST exceeded approximately 9 h/day. Conclusions: Based on a limited number of studies, this meta-analysis provides a starting point for considering a cut-off of daily sedentary time, suggesting older adults spend less time in daily sitting.

scholarly journals The Prevalence of Sarcopenia in Chinese Older Adults: Meta-Analysis and Meta-Regression

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1441
Author(s):  
Zi Chen ◽  
Wei-Ying Li ◽  
Mandy Ho ◽  
Pui-Hing Chau
Keyword(s):  
Older Adults ◽  
Nursing Homes ◽  
Meta Analysis ◽  
Older Population ◽  
Chinese Older Adults ◽  
Factors Associated ◽  
Pooled Prevalence ◽  
Different Populations ◽  
Meta Regression ◽  
Older Chinese

Sarcopenia, with risk factors such as poor nutrition and physical inactivity, is becoming prevalent among the older population. The aims of this study were (i) to systematically review the existing data on sarcopenia prevalence in the older Chinese population, (ii) to generate pooled estimates of the sex-specific prevalence among different populations, and (iii) to identify the factors associated with the heterogeneity in the estimates across studies. A search was conducted in seven databases for studies that reported the prevalence of sarcopenia in Chinese older adults, aged 60 years and over, published through April 2020. We then performed a meta-analysis to estimate the pooled prevalence, and investigated the factors associated with the variation in the prevalence across the studies using meta-regression. A total of 58 studies were included in this review. Compared with community-dwelling Chinese older adults (men: 12.9%, 95% CI: 10.7–15.1%; women: 11.2%, 95% CI: 8.9–13.4%), the pooled prevalence of sarcopenia in older adults from hospitals (men: 29.7%, 95% CI:18.4–41.1%; women: 23.0%, 95% CI:17.1–28.8%) and nursing homes (men: 26.3%, 95% CI: 19.1 to 33.4%; women: 33.7%, 95% CI: 27.2 to 40.1%) was higher. The multivariable meta-regression quantified the difference of the prevalence estimates in different populations, muscle mass assessments, and areas. This study yielded pooled estimates of sarcopenia prevalence in Chinese older adults not only from communities, but also from clinical settings and nursing homes. This study added knowledge to the current epidemiology literature about sarcopenia in older Chinese populations, and could provide background information for future preventive strategies, such as nutrition and physical activity interventions, tailored to the growing older population.

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