Physical activity to improve cognition in older adults: can physical activity programs enriched with cognitive challenges enhance the effects? A systematic review and meta-analysis

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Effects of different lower-limb sensory stimulation strategies on postural regulation – A systematic review and meta-analysis

Systematic reviews of balance control have tended to only focus on the effects of single lower-limb stimulation strategies, and a current limitation is the lack of comparison between different relevant stimulation strategies. The aim of this systematic review and meta-analysis was to examine evidence of effects of different lower-limb sensory stimulation strategies on postural regulation and stability. Moderate- to high- pooled effect sizes (Unbiased (Hedges’ g) standardized mean differences (SMD) = 0.31 – 0.66) were observed with the addition of noise in a Stochastic Resonance Stimulation Strategy (SRSS), in three populations (i.e., healthy young adults, older adults, and individuals with lower-limb injuries), and under different task constraints (i.e., unipedal, bipedal, and eyes open). A Textured Material Stimulation Strategy (TMSS) enhanced postural control in the most challenging condition – eyes-closed on a stable surface (SMD = 0.61), and in older adults (SMD = 0.30). The Wearable Garments Stimulation Strategy (WGSS) showed no or adverse effects (SMD = -0.68 – 0.05) under all task constraints and in all populations, except in individuals with lower-limb injuries (SMD = 0.20). Results of our systematic review and meta-analysis revealed that future research could consider combining two or more stimulation strategies in intervention treatments for postural regulation and balance problems, depending on individual need

Tai Chi Improves Cognition and Plasma BDNF in Older Adults With Mild Cognitive Impairment: A Randomized Controlled Trial

Background. Effects of Tai Chi (TC) on specific cognitive function and mechanisms by which TC may improve cognition in older adults with amnestic mild cognitive impairment (a-MCI) remain unknown. Objective. To examine the effects of TC on cognitive functions and plasma biomarkers (brain-derived neurotrophic factor [BDNF], tumor necrosis factor-α [TNF-α], and interleukin-10 [IL-10]) in a-MCI. Methods. A total of 66 older adults with a-MCI (mean age = 67.9 years) were randomized to either a TC (n = 33) or a control group (n = 33). Participants in the TC group learned TC with a certified instructor and then practiced at home for 50 min/session, 3 times/wk for 6 months. The control group received educational material that covered information related to cognition. The primary outcome was cognitive performance, including Logical Memory (LM) delayed recall, Block Design, Digit Span, and Trail Making Test B minus A (TMT B-A). The secondary outcomes were plasma biomarkers, including BDNF, TNF-α, and IL-10. Results. At the end of the trial, performance on the LM and TMT B-A was significantly better in the TC group compared with the control group after adjusting for age, gender, and education (P <.05). Plasma BDNF level was significantly increased for the TC group, whereas the other outcome measures were similar between the 2 groups after adjusting for age and gender (P <.05). Conclusions. TC training significantly improved memory and the mental switching component of executive function in older adults with a-MCI, possibly via an upregulation of BDNF

Spatial variability during gait initiation while dual tasking is increased in individuals with mild cognitive impairment

Background Gait initiation (GI) is a complex transition phase of gait that can induce postural instability. Gait impairment has been well documented in people with Alzheimer’s disease, but it is still inconclusive in individuals with Mild Cognitive Impairment (MCI). Previous studies have usually investigated gait performance of cognitive impaired persons under steady state walking. Objective This study aimed to examine spatiotemporal variability during GI under single- and dual-task conditions in people with and without MCI. Methods Spatiotemporal stepping characteristics and variability under single- and dual-task conditions (counting backwards by 3s) were assessed in 30 older adults with MCI and 30 cognitively intact controls. Mean and coefficients of variation (COV) of swing time, step time, step length and step width were compared between the two groups. Results Mixed-model repeated measures ANOVA revealed a significant Group x Walking condition interaction for COV of step length and step width (P Conclusions Step length and step width variability is increased in people with MCI during GI, particularly in a condition involving a secondary cognitive task. These findings suggest that individuals with MCI have reduced balance control when undertaking a challenging walking task such as gait initiation, and this is exacerbated with an added cognitive task. Future studies should prospectively investigate the relationship between GI variability and fall risk in this population