Acute High-Intensity Interval Exercise Modulates Corticospinal Excitability in Older Adults

Optimal exercise intensity for improving executive function in patients with attention deficit hyperactivity disorder: systematic review and network meta-analysis

This study aimed to compare and rank the effectiveness of optimal exercise intensity in improving executive function in patients with ADHD (Attention deficit hyperactivity disorder, ADHD) through a comprehensive comparison of direct and indirect evidence. A systematic search was performed in five electronic databases to explore the optimal exercise intensity for improving executive function in patients with ADHD by directly and indirectly comparing a variety of exercise intervention intensities. In addition, the isolated effects of exercise on improving executive function in patients with ADHD were explored through classical meta-analysis of paired direct comparisons. Twenty-nine studies were retrieved and included in this study. Classical paired meta-analysis showed that for the patients with ADHD in the age group of 7-17 years, statistical difference was observed for all the parameters of exercise interventions (intensity, frequency, period, and training method), the three dimensions of executive function, the use of medication or not, the high and low quality of the methodological approach. Network meta-analysis showed that high-intensity exercise training was optimal for improving working memory (97.4%) and inhibitory function (85.7%) in patients with ADHD. Meanwhile, moderate-intensity exercise training was optimal for improving cognitive flexibility (77.3%) in patients with ADHD. Moderate to high intensity exercise training shows potential for improving executive function in these patients. Therefore, we recommend applying high-intensity exercise intervention to improve executive function in patients with ADHD to achieve substantial improvement.

A 12-week in-phase bilateral upper limb exercise protocol promoted neuroplastic and clinical changes in people with relapsing remitting multiple sclerosis: A registered report randomized single-case concurrent multiple baseline study

INTRODUCTION

Relapsing-Remitting Multiple Sclerosis manifests various motor symptoms including impairments in corticospinal tract integrity, whose symptoms can be assessed using transcranial magnetic stimulation. Several factors, such as exercise and interlimb coordination, can influence the plastic changes in corticospinal tract. Previous work in healthy and chronic stroke survivors showed that the greatest improvement in corticospinal plasticity occurred during in-phase bilateral exercises of the upper limbs. Altered corticospinal plasticity due to bilateral lesions in the central nervous system is common after Multiple Sclerosis, yet the effect of in-phase bilateral exercise on the bilateral corticospinal plasticity in this cohort remains unclear. Our aim was to investigate the effects of in-phase bilateral exercises on central motor conduction time, motor evoked potential amplitude and latency, motor threshold and clinical measures in people with Relapsing-Remitting Multiple Sclerosis.

METHODS

Five people were randomized and recruited in this single case concurrent multiple baseline design study. The intervention protocol lasted for 12 consecutive weeks (30-60 minutes /session x 3 sessions / week) and included in-phase bilateral upper limb movements, adapted to different sports activities and to functional motor training. To define the functional relation between the intervention and the results, we conducted a visual analysis. If a potential sizeable effect was observed, we subsequently performed a statistical analysis.

RESULTS

Results demonstrated bilateral reduction of the motor threshold alongside with improvement of all clinical measures, but not in any other corticospinal plasticity measures.

CONCLUSION

Our preliminary findings suggest that in-phase bilateral exercise affects motor threshold in people with Relapsing-Remitting Multiple Sclerosis. Therefore, this measure could potentially serve as a proxy for detecting corticospinal plasticity in this cohort. However, future studies with larger sample sizes should validate and potentially establish the effect of in-phase bilateral exercise on the corticospinal plasticity and clinical measures in this cohort.

TRIAL REGISTRATION

Clinical trial registration: ClinicalTrials.gov NCT05367947.

Neurophysiological effects of acute aerobic exercise in young adults: a systematic review and meta-analysis

Evidence continues to accumulate that acute aerobic exercise (AAE) impacts neurophysiological excitability as measured by transcranial magnetic stimulation (TMS). Yet, uncertainty exists about which TMS measures are modulated after AAE in young adults. The influence of AAE intensity and duration of effects are also uncertain. This pre-registered meta-analysis (CRD42017065673) addressed these uncertainties by synthesizing data from 23 studies (including 474 participants) published until February 2024. Meta-analysis was run using a random-effects model and Hedge's g used as effect size. Our results demonstrated a decrease in short-interval intracortical inhibition (SICI) following AAE (g = 0.27; 95 % CI [0.16-0.38]; p <.0001), particularly for moderate (g = 0.18; 95 % CI [0.05-0.31]; p <.01) and high (g = 0.49; 95 % CI [0.27-0.71]; p <.0001) AAE intensities. These effects remained for 30 minutes after AAE. Additionally, increased corticospinal excitability was only observed for high intensity AAE (g = 0.28; 95 % CI, [0.07-0.48]; p <.01). Our results suggest potential mechanisms for inducing a more susceptible neuroplastic environment following AAE.

Impact of Acute High-intensity Interval Training on Cortical Excitability, M1-related Cognitive Functions, and Myokines: A Randomized Crossover Study

High-intensity interval training (HIIT) is a time-efficient, safe, and feasible exercise type that can be utilized across different ages and health status. This randomized cross-over study aimed to investigate the effect of acute HIIT on cortical excitability, M1-related cognitive functions, cognition-related myokines, brain-derived neurotrophic factor (BDNF), and Cathepsin B (CTSB). Twenty-three sedentary young adults (mean age: 22.78 years ± 2.87; 14 female) participated in a cross-over design involving two sessions: either 23 min of HIIT or seated rest. Before and after the sessions, cortical excitability was measured using transcranial magnetic stimulation, and M1-related cognitive functions were assessed by the n-back test and mental rotation test. Serum levels of BDNF and CTSB were assessed using the ELISA method before and after the HIIT intervention. We demonstrated that HIIT improved mental rotation and working memory, and increased serum levels of BDNF and CTSB, whereas cortical excitability did not change. Our findings provide evidence that one session of HIIT is effective on M1-related cognitive functions and cognition-related myokines. Future research is warranted to determine whether such findings are transferable to different populations, such as cognitively at-risk children, adults, and older adults, and to prescribe effective exercise programs.

Neurophysiological and Clinical Outcomes in Episodic Migraine Without Aura: A Cross-Sectional Study

PURPOSE

The aim of this study was to assess differences between people with episodic migraine and healthy controls in some neurophysiological and clinical outcomes, which, in turn, may highlight the differences in sensory processing, especially in cortical excitability, pain processing, and executive function.

METHODS

A cross-sectional study was performed, including the following outcomes: pressure pain thresholds with algometry; resting motor threshold, short-interval intracortical inhibition, and intracortical facilitation with transcranial magnetic stimulation; and executive functions with the trail making test and the frontal assessment battery.

RESULTS

Thirty adults with migraine (36 ± 10 years) and 30 healthy controls (29 ± 14 years) were included in this study. Compared with the healthy controls, participants with migraine presented lower pressure pain thresholds values in all the assessed muscles ( P < 0.001), lower resting motor threshold (-10.5% of the stimulator output, 95% CI: -16.8 to -4.2, P = 0.001, Cohen d = 0.869) and higher short-interval intracortical inhibition motor-evoked potential's amplitude at 3 ms (0.25, 95% CI: 0.05 to 0.46, P = 0.015, Cohen d = 0.662), and worse performances both in trail making test (7.1, 95% CI: 0.9 to 13.4, P = 0.027, Cohen d = 0.594) and frontal assessment battery (-1.1, 95% CI: -1.7 to -0.5, P = 0.001, Cohen d = 0.915).

CONCLUSIONS

Participants with migraine presented significant differences in cortical excitability, executive functions, and pressure pain thresholds, compared with healthy controls.

Single Exercise for Core Symptoms and Executive Functions in ADHD: A Systematic Review and Meta-Analysis

OBJECTIVES

A systematic review and meta-analysis of studies of single exercise on core symptoms and executive function in adolescents with ADHD.

METHODS

Four databases were searched for studies of the effects of single exercise on core symptoms and executive functioning in adolescents with ADHD.

RESULTS

Thirteen studies were included, and a single session of exercise had small effect-size improvements in core symptoms and executive function in adolescents with ADHD: 10 to 13 year olds in the early adolescent-elementary school years and 18 to 24 year olds in the late adolescent-college years. Moderate-intensity continuous training, high-intensity interval training, single sessions of less than 30 minutes, and single sessions of 30 minutes and more significantly improved cycling training, attention, inhibition, substance use, and pre-study abstinence.

CONCLUSIONS

A single session of exercise had an overall ameliorative effect on core symptoms and executive function in adolescents with ADHD.

Ageing attenuates exercise-enhanced motor cortical plasticity

Cardiorespiratory exercise is known to modulate motor cortical plasticity in young adults, but the influence of ageing on this relationship is unknown. Here, we compared the effects of a single session of cardiorespiratory exercise on motor cortical plasticity in young and older adults. We acquired measures of cortical excitatory and inhibitory activity of the primary motor cortex using transcranial magnetic stimulation (TMS) from 20 young (mean ± SD = 25.30 ± 4.00 years, 14 females) and 20 older (mean ± SD = 64.10 ± 6.50 years, 11 females) healthy adults. Single- and paired-pulse TMS measurements were collected before and after a 20 min bout of high-intensity interval cycling exercise or an equivalent period of rest, and again after intermittent theta burst stimulation (iTBS). In both young (P = 0.027, Cohen's d = 0.87) and older adults (P = 0.006, Cohen's d = 0.85), there was an increase in glutamatergic excitation and a reduction in GABAergic inhibition from pre- to postexercise. However, in contrast to younger adults, older adults showed an attenuated plasticity response to iTBS following exercise (P = 0.011, Cohen's d = 0.85). These results demonstrate an age-dependent decline in cortical plasticity and indicate that a preceding bout of high-intensity interval exercise might be less effective for enhancing primary motor cortex plasticity in older adults. Our findings align with the hypothesis that the capacity for cortical plasticity is altered in older age. KEY POINTS: Exercise enhances motor cortical plasticity in young adults, but how ageing influences this effect is unknown. Here, we compared primary motor cortical plasticity responses in young and older adults before and after a bout of high-intensity interval exercise and again after a plasticity-inducing protocol, intermittent theta burst stimulation. In both young and older adults, exercise led to an increase in glutamatergic excitation and a reduction in GABAergic inhibition. Our key result was that older adults showed an attenuated plasticity response to theta burst stimulation following exercise, relative to younger adults. Our findings demonstrate an age-dependent decline in exercise-enhanced cortical plasticity and indicate that a preceding bout of high-intensity interval exercise might be less effective for enhancing primary motor cortex plasticity in older adults.

Improved processing speed and decreased functional connectivity in individuals with chronic stroke after paired exercise and motor training

After stroke, impaired motor performance is linked to an increased demand for cognitive resources. Aerobic exercise improves cognitive function in neurologically intact populations and may be effective in altering cognitive function post-stroke. We sought to determine if high-intensity aerobic exercise paired with motor training in individuals with chronic stroke alters cognitive-motor function and functional connectivity between the dorsolateral prefrontal cortex (DLPFC), a key region for cognitive-motor processes, and the sensorimotor network. Twenty-five participants with chronic stroke were randomly assigned to exercise (n = 14; 66 ± 11 years; 4 females), or control (n = 11; 68 ± 8 years; 2 females) groups. Both groups performed 5-days of paretic upper limb motor training after either high-intensity aerobic exercise (3 intervals of 3 min each, total exercise duration of 23-min) or watching a documentary (control). Resting-state fMRI, and trail making test part A (TMT-A) and B were recorded pre- and post-intervention. Both groups showed implicit motor sequence learning (p < 0.001); there was no added benefit of exercise for implicit motor sequence learning (p = 0.738). The exercise group experienced greater overall cognitive-motor improvements measured with the TMT-A. Regardless of group, the changes in task score, and dwell time during TMT-A were correlated with a decrease in DLPFC-sensorimotor network functional connectivity (task score: p = 0.025; dwell time: p = 0.043), which is thought to reflect a reduction in the cognitive demand and increased automaticity. Aerobic exercise may improve cognitive-motor processing speed post-stroke.

Hippocampal blood flow rapidly and preferentially increases after a bout of moderate-intensity exercise in older adults with poor cerebrovascular health

Over the course of aging, there is an early degradation of cerebrovascular health, which may be attenuated with aerobic exercise training. Yet, the acute cerebrovascular response to a single bout of exercise remains elusive, particularly within key brain regions most affected by age-related disease processes. We investigated the acute global and region-specific cerebral blood flow (CBF) response to 15 minutes of moderate-intensity aerobic exercise in older adults (≥65 years; n = 60) using arterial spin labeling magnetic resonance imaging. Within 0-6 min post-exercise, CBF decreased across all regions, an effect that was attenuated in the hippocampus. The exercise-induced CBF drop was followed by a rebound effect over the 24-minute postexercise assessment period, an effect that was most robust in the hippocampus. Individuals with low baseline perfusion demonstrated the greatest hippocampal-specific CBF effect post-exercise, showing no immediate drop and a rapid increase in CBF that exceeded baseline levels within 6-12 minutes postexercise. Gains in domain-specific cognitive performance postexercise were not associated with changes in regional CBF, suggesting dissociable effects of exercise on acute neural and vascular plasticity. Together, the present findings support a precision-medicine framework for the use of exercise to target brain health that carefully considers age-related changes in the cerebrovascular system.

Investigation of in-phase bilateral exercise effects on corticospinal plasticity in relapsing remitting multiple sclerosis: A registered report single-case concurrent multiple baseline design across five subjects

Relapsing-remitting Multiple Sclerosis is the most common demyelinating neurodegenerative disease and is characterized by periods of relapses and generation of various motor symptoms. These symptoms are associated with the corticospinal tract integrity, which is quantified by means of corticospinal plasticity which can be probed via transcranial magnetic stimulation and assessed with corticospinal excitability measures. Several factors, such as exercise and interlimb coordination, can influence corticospinal plasticity. Previous work in healthy and in chronic stroke survivors showed that the greatest improvement in corticospinal plasticity occurred during in-phase bilateral exercises of the upper limbs. During in-phase bilateral movement, both upper limbs are moving simultaneously, activating the same muscle groups and triggering the same brain region respectively. Altered corticospinal plasticity due to bilateral cortical lesions is common in MS, yet, the impact of these type of exercises in this cohort is unclear. The aim of this concurrent multiple baseline design study is to investigate the effects of in-phase bilateral exercises on corticospinal plasticity and on clinical measures using transcranial magnetic stimulation and standardized clinical assessment in five people with relapsing-remitting MS. The intervention protocol will last for 12 consecutive weeks (30-60 minutes /session x 3 sessions/week) and include in-phase bilateral movements of the upper limbs, adapted to different sports activities and to functional training. To define functional relation between the intervention and the results on corticospinal plasticity (central motor conduction time, resting motor threshold, motor evoked potential amplitude and latency) and on clinical measures (balance, gait, bilateral hand dexterity and strength, cognitive function), we will perform a visual analysis and if there is a potential sizeable effect, we will perform statistical analysis. A possible effect from our study, will introduce a proof-of-concept for this type of exercise that will be effective during disease progression. Trial registration: ClinicalTrials.gov NCT05367947.

A Systematic Review on the Effects of Acute Aerobic Exercise on Neurophysiological, Molecular, and Behavioral Measures in Chronic Stroke

BACKGROUND

A single bout of aerobic exercise (AE) can produce changes in neurophysiological and behavioral measures in healthy individuals and those with stroke. However, the effects of AE-priming effects on neuroplasticity markers and behavioral measures are unclear.

OBJECTIVES

This systematic review aimed to examine the effects of AE on neuroplasticity measures, such as corticomotor excitability (CME), molecular markers, cortical activation, motor learning, and performance in stroke.

METHODS

A literature search was performed in MEDLINE, CINAHL, Scopus, and PsycINFO databases. Randomized and non-randomized studies incorporating acute AE in stroke were selected. Two reviewers independently assessed the risk of bias and methodological rigor of the studies and extracted data on participant characteristics, exercise interventions, and neuroplasticity related outcomes. The quality of transcranial magnetic stimulation reported methods was assessed using a standardized checklist.

RESULTS

A total of 16 studies were found suitable for inclusion. Our findings suggest mixed evidence for the effects of AE on CME, limited to no effects on intracortical inhibition and facilitation and some evidence for modulating brain derived neurotrophic factor levels, motor learning, and cortical activation. Exercise intensities in the moderate to vigorous range showed a trend towards better effects on neuroplasticity measures.

CONCLUSION

It appears that choosing a moderate to vigorous exercise paradigm for at least 20 to 30 minutes may induce changes in some neuroplasticity parameters in stroke. However, these findings necessitate prudent consideration as the studies were diverse and had moderate methodological quality. There is a need for a consensus on an exercise priming paradigm and for good-quality, larger controlled studies.