The effects of exercise on cognition post-stroke: are there sex differences? A systematic review and meta-analysis

Effects of exercise on post-stroke cognitive function: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

A growing body of research examining the effect of exercise on cognitive function in stroke patients, while findings of available studies were conflicting.

OBJECTIVES

We aimed to estimate the effect of exercise on cognitive function in stroke patients.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Web of Science, Embase, Cochrane, and Scopus electronic databases, through 13 March 2023. The three-level restricted maximum likelihood random effects model was used to synthesize the data.

RESULTS

Twenty-five studies met the inclusion criteria. There was a significant effect of exercise on improving cognitive function in stroke patients (Cohen's d = 0.37, 95% CI, 0.16 to 0.58, p < 0.01, I2  = 22.12%). Subgroup analysis showed that exercise significantly improved memory. In addition, aerobic exercise, exercise conducted 12 weeks or more, 3 times or more per week, less than 60 minutes per session, less than 180 minutes per week, and up to 12 months post-stroke increased cognitive function significantly.

CONCLUSIONS

Exercise improved cognitive function in stroke patients. To improve cognitive function, this meta-analysis provides clinicians with evidence to recommend that stroke patients participate in aerobic exercise at least 3 times per week for 30-60 minutes, with a goal of 180 minutes per week being achieved by increasing the frequency of exercise. Exercise initiated within 12 months post-stroke and continued for 12 weeks or more is most beneficial for improving cognitive function.

Physical exercise-induced circAnks1b upregulation promotes protective endoplasmic reticulum stress and suppresses apoptosis via miR-130b-5p/Pak2 signaling in an ischemic stroke model

AIMS

Physical exercise (PE) can accelerate post-stroke recovery. This study investigated contributions of circRNAs to PE-induced improvements in post-stroke neurological function.

METHODS

Rats subjected to transient middle cerebral artery occlusion were left sedentary or provided running-wheel access for 4 weeks during recovery. CircRNAs from peri-infarct cortex were identified by high-throughput sequencing, and interactions with miRNAs by immunoprecipitation, fluorescence in suit hybridization, and dual-luciferase reporter assays. In vivo circRNA knockdown was achieved using shRNA-AAVs and in vitro overexpression by plasmid transfection. Transmission electron microscopy, western blotting, and TUNEL assays were conducted to explore circRNA contributions to endoplasmic reticulum (ER) stress and neuronal apoptosis. CircRNA levels were measured in plasma from stroke patients by qRT-PCR and associations with neurological scores assessed by Pearson's correlation analysis.

RESULTS

PE upregulated circAnks1b, reduced infarct volume, and mitigated neurological dysfunction, while circAnks1b knockdown exacerbated neurological dysfunction and increased infarct size despite PE. CircAnks1b sponged miR-130b-5p, thereby disinhibiting Pak2 expression. Conversely, Pak2 downregulation disrupted PE-mediated protective ER stress, leading to reduced IRE1/XBP1 and heightened apoptosis. Plasma circAnks1b was higher in stroke patients receiving PE than sedentary patients and correlated negatively with neurological scores.

CONCLUSIONS

CircAnks1b upregulation may be an effective therapeutic strategy for post-stroke recovery.

What are the effects of acute exercise and exercise training on cerebrovascular hemodynamics following stroke? A systematic review and meta-analysis

INTRODUCTION

Limited data exist regarding the effects of acute exercise and exercise training on cerebrovascular hemodynamic variables post-stroke.

PURPOSE

This systematic review and meta-analysis 1) examined the effects of acute exercise and exercise training on cerebrovascular hemodynamic variables reported in the stroke exercise literature; and 2) synthesized the peak middle cerebral artery blood velocity (MCAv) achieved during an acute bout of moderate-intensity exercise in individuals post-stroke.

METHODS

Six databases (MEDLINE, EMBASE, Web of Science, CINAHL, PsycINFO, AMED) were searched from inception to December 1^st 2021, for studies that examined the effect of acute exercise or exercise training on cerebrovascular hemodynamics in adults post-stroke. Two reviewers conducted title and abstract screening, full-text evaluation, data extraction, and quality appraisal. Random effects models were used in meta-analysis.

RESULTS

Nine studies, including 4 acute exercise (n=61) and 5 exercise training studies (n=193), were included. Meta-analyses were not statistically feasible for several cerebrovascular hemodynamic variables. Descriptive analysis reveals that exercise training may increase cerebral blood flow and cerebrovascular reactivity to carbon dioxide among individuals post-stroke. Meta-analysis of three acute exercise studies revealed no significant changes in MCAv during acute moderate intensity exercise (n=48 participants, mean difference = 5.2 cm/s, 95% CI [-0.6, 11.0], P=0.08) compared to resting MCAv values.

CONCLUSION

This review suggests that individuals post-stroke may have attenuated cerebrovascular hemodynamics as measured by the MCAv during acute moderate-intensity exercise. Higher quality research utilizing agreed upon hemodynamic variables are needed to synthesize the effects of exercise training on cerebrovascular hemodynamics post-stroke.

Effects of Combined Interventions with Aerobic Physical Exercise and Cognitive Training on Cognitive Function in Stroke Patients: A Systematic Review

(1) Background: Stroke is a major cause of permanent disability in multiple functions, including the cognitive domain. Since both cognitive training and aerobic physical exercise may exert positive effects on cognition after stroke, one may expect synergistic benefits when combining both interventions. (2) Methods: We carried out a systematic search of studies testing, in adult stroke patients, whether structured aerobic exercise combined with cognitive training led to higher cognitive benefits than either of these interventions when applied singly, or than interventions not including aerobic exercise or cognitive training. (3) Results: Five fair-quality randomized controlled trials fulfilled the search criteria. Exercise intensity was moderate-vigorous and cognitive training was mainly computer-based. The studies were heterogeneous regarding the cognitive tests used, and for this reason, a meta-analysis was not performed. Only three studies included follow-up assessment. The combined intervention was associated with pre-post improvement in at least one cognitive test in all the studies, and with higher positive effects compared to other conditions (although statistical significance was not always reached) in four studies. (4) Conclusions: Further trials including a long-term follow-up and comprehensive neuropsychological testing should be undertaken to determine whether combined aerobic exercise and cognitive training leads to additive cognitive benefits after stroke.

Prevalence of Balance Impairment and Factors Associated with Balance among Patients with Stroke. A Cross Sectional Retrospective Case Control Study

Stroke is a major cause of disability worldwide, and balance impairments are common disabling factors in patients with stroke, leading to falls. Thus, the study objectives were as follows: (i) To find the prevalence of balance impairment among patients with stroke. (ii) To find out the factors associated with balance impairment in patients with stroke. This cross-sectional retrospective case control study involved eighty-one post stroke patients with a mean age of 58.36 ± 14.06, recruited from six hospitals, who underwent an assessment of balance, walking speed, depression and isometric strength of the ankle and knee. These patients were later categorized into subjects with good balance (<45) in the Berg balance scale (BBS) and those with poor balance (≥45), as cases and controls, to assess the factors associated with balance impairment using binary logistic regression. The prevalence of balance impairment among patients with stroke was 48.1%. The reduction in power of knee flexors (OR = 0.858), knee extensors (OR = 0.880) and ankle dorsiflexors (OR = 0.820) was found to be significantly associated with balance impairment, along with speed (OR = 1.187 (95% CI = 1.100, 1.280)), depression (OR = 1.331 (95% CI = 1.055-1.679)) and activities of daily living (OR = 0.313 (95% CI = 0.150-0.650)). In summary, around half of the patients with stroke exhibited balance impairments, with females being more prone.