Non-invasive brain stimulation for improving gait, balance, and lower limbs motor function in stroke.

OBJECTIVES: This systematic review and meta-analysis aim to summarize and analyze the available evidence of non-invasive brain stimulation/spinal cord stimulation on gait, balance and/or lower limb motor recovery in stroke patients. METHODS: The PubMed database was searched from its inception through to 31/03/2021 for randomized controlled trials investigating repetitive transcranial magnetic stimulation or transcranial/trans-spinal direct current/alternating current stimulation for improving gait, balance and/or lower limb motor function in stroke patients. RESULTS: Overall, 25 appropriate studies (including 657 stroke subjects) were found. The data indicates that non-invasive brain stimulation/spinal cord stimulation is effective in supporting recovery. However, the effects are inhomogeneous across studies: (1) transcranial/trans-spinal direct current/alternating current stimulation induce greater effects than repetitive transcranial magnetic stimulation, and (2) bilateral application of non-invasive brain stimulation is superior to unilateral stimulation. CONCLUSIONS: The current evidence encourages further research and suggests that more individualized approaches are necessary for increasing effect sizes in stroke patients.

Non-invasive brain stimulation in modulation of mental rotation ability: A systematic review and meta-analysis.

Mental rotation, the ability to manipulate mental images, is an important function in human cognition. This systematic review and meta-analysis investigates the potential of non-invasive brain stimulation in modulation of this component of visuo-spatial perception. The PubMed database was reviewed prior to 31 September 2020 on randomized controlled trials investigating the effects of repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), and transcranial alternating current stimulation (tACS) on the mental rotation ability in healthy persons. A total of 17 studies (including 485 subjects) matched our inclusion criteria. Within their scope, overall, 46 sham-controlled experiments were performed. Methodology and results of each experiment are presented in a meta-analysis. The data show a large variety of methods and effects. The influence of (1) stimulation-technique (tDCS, tACS, and rTMS), (2) stimulation protocol (anodal, cathodal, bilateral tDCS, tACS, high-frequency rTMS, low-frequency rTMS, paired pulse rTMS, and theta burst stimulation), (3) stimulation timing (preconditioning and simultaneous), (4) stimulation location (left, right hemisphere, frontal, and parietal area), and (5) stimulus type (bodily and non-bodily) is discussed. The data indicate a beneficial effect of anodal tDCS and of tACS and no effect of cathodal tDCS on the mental rotation ability. Bilateral tDCS protocols both improved and worsened the parameters assessed. The small effect sizes obtained in mostly rTMS experiments require cautious interpretation.

Aquatic therapy in stroke rehabilitation: systematic review and meta-analysis.

The main object of this systematic review and meta-analysis is to collect the available evidence of aquatic therapy in stroke rehabilitation and to investigate the effect of this intervention in supporting stroke recovery. The PubMed, the Cochrane Central Register of Controlled Trials and the PEDro databases were searched from their inception through to 31/05/2020 on randomized controlled trials evaluating the effect of aquatic therapy on stroke recovery. Subjects´ characteristics, methodological aspects, intervention description, and outcomes were extracted. Effect sizes were calculated for each study and outcome. Overall, 28 appropriate studies (N = 961) have been identified. A comparison with no intervention indicates that aquatic therapy is effective in supporting walking, balance, emotional status and health-related quality of life, spasticity, and physiological indicators. In comparison with land-based interventions, aquatic therapy shows superior effectiveness on balance, walking, muscular strength, proprioception, health-related quality of life, physiological indicators, and cardiorespiratory fitness. Only on independence in activities of daily living the land- and water-based exercise induce similar effects. Established concepts of water-based therapy (such as the Halliwick, Ai Chi, Watsu, or Bad Ragaz Ring methods) are the most effective, aquatic treadmill walking is the least effective. The current evidence is insufficient to support this therapy form within evidence-based rehabilitation. However, the available data indicate that this therapy can significantly improve a wide range of stroke-induced disabilities. Future research should devote more attention to this highly potent intervention.

Resting motor threshold in the course of hand motor recovery after stroke: a systematic review.

BACKGROUND: Resting motor threshold is an objective measure of cortical excitability. Numerous studies indicate that the success of motor recovery after stroke is significantly determined by the direction and extent of cortical excitability changes. A better understanding of this topic (particularly with regard to the level of motor impairment and the contribution of either cortical hemisphere) may contribute to the development of effective therapeutical strategies in this cohort. OBJECTIVES: This systematic review collects and analyses the available evidence on resting motor threshold and hand motor recovery in stroke patients. METHODS: PubMed was searched from its inception through to 31/10/2020 on studies investigating resting motor threshold of the affected and/or the non-affected hemisphere and motor function of the affected hand in stroke cohorts. RESULTS: Overall, 92 appropriate studies (including 1978 stroke patients and 377 healthy controls) were identified. The analysis of the data indicates that severe hand impairment is associated with suppressed cortical excitability within both hemispheres and with great between-hemispheric imbalance of cortical excitability. Favorable motor recovery is associated with an increase of ipsilesional motor cortex excitability and reduction of between-hemispheric imbalance. The direction of change of contralesional motor cortex excitability depends on the amount of hand motor impairment. Severely disabled patients show an increase of contralesional motor cortex excitability during motor recovery. In contrast, recovery of moderate to mild hand motor impairment is associated with a decrease of contralesional motor cortex excitability. CONCLUSIONS: This data encourages a differential use of rehabilitation strategies to modulate cortical excitability. Facilitation of the ipsilesional hemisphere may support recovery in general, whereas facilitation and inhibition of the contralesional hemisphere may enhance recovery in severe and less severely impaired patients, respectively.

Noninvasive brain stimulation in rehabilitation of hemispatial neglect after stroke.

BACKGROUND: Noninvasive brain stimulation can modulate neural processing within the motor cortex and thereby might be beneficial in the rehabilitation of hemispatial neglect after stroke. METHODS: We review the pertinent literature regarding the use of transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation in order to facilitate recovery of hemispatial neglect after stroke. RESULTS: Twenty controlled trials (including 443 stroke patients) matched our inclusion criteria. Methodology and results of each study are presented in a comparative approach. Current data seem to indicate a better efficiency of repetitive transcranial magnetic stimulation, compared to tDCS to ameliorate hemispatial neglect after stroke. CONCLUSIONS: Noninvasive brain stimulation has the potential to facilitate recovery of hemispatial neglect after stroke, but until today, there are not enough data to claim its routine use.

Ergometer Training in Stroke Rehabilitation: Systematic Review and Meta-analysis.

OBJECTIVE: Ergometer training is routinely used in stroke rehabilitation. Through this meta-analysis, we sought to discover the strength of evidence of its effects. DATA SOURCE: The PubMed database and PEDro database were reviewed prior to January 22, 2019. STUDY SELECTION: Randomized controlled trials investigating the effects of ergometer training on stroke recovery were selected. DATA EXTRACTION: Two reviewers independently selected the studies, performed independent data extraction, and assessed the risk of bias. DATA SYNTHESIS: A total of 28 studies (including 1115 subjects with stroke) were included. The data indicates that (1) ergometer training leads to a significant improvement in walking ability, cardiorespiratory fitness, motor function, muscular force of the lower limbs, balance and postural control, spasticity, cognitive abilities, and the brain's resistance to damage and degeneration; (2) neuromuscular functional electrical stimulation-assisted ergometer training is more efficient than ergometer training alone; (3) high-intensity ergometer training is more efficient that low-intensity ergometer training; and (4) ergometer training is more efficient than other therapies in supporting cardiorespiratory fitness, independence in activities of daily living, and balance and postural control, but less efficient in improving walking ability. CONCLUSIONS: Ergometer training can support motor recovery after stroke. However, current data is insufficient for evidence-based rehabilitation. More data is required about the effects of ergometer training on cognitive abilities, emotional status, and quality of life in subjects with a history of stroke.

Resistance training in stroke rehabilitation: systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis investigates the effects of resistance training in supporting the recovery in stroke patients. DATA SOURCES: PubMed, the Cochrane Central Register of Controlled Trials and the PEDro databases were reviewed up to 30 April 2020. REVIEW METHODS: Randomized controlled trials were included, who compared: (i) resistance training with no intervention, (ii) resistance training with other interventions and (iii) different resistance training protocols in stroke rehabilitation. RESULTS: Overall 30 trials (n = 1051) were enrolled. The parameters evaluated were: (1) gait, (2) muscular force and motor function, (3) mobility, balance and postural control, (4) health related quality of life, independence and reintegration, (5) spasticity and hypertonia, (6) cardiorespiratory fitness, (7) cognitive abilities and emotional state and (8) other health-relevant physiological indicators. The data indicates that: (i) resistance training is beneficial for the majority of parameters observed, (ii) resistance training is superior to other therapies on muscular force and motor function of lower and upper limbs, health related quality of life, independence and reintegration and other health-relevant physiological indicators, not significantly different from other therapies on walking ability, mobility balance and postural control and spasticity and hypertonia, and inferior to ergometer training on cardiorespiratory fitness and (iii) the type of resistance training protocol significantly impacts its effect; leg press is more efficient than knee extension and high intensity training is superior than low intensity training. CONCLUSION: Current data indicates that resistance training may be beneficial in supporting the recovery of stroke patients. However, the current evidence is insufficient for evidence-based rehabilitation.

Cycle ergometer training vs resistance training in ICU-acquired weakness.

OBJECTIVES: We investigated the effectiveness of cycle ergometer training and resistance training to enhance the efficiency of standard care to improve walking ability, muscular strength of the lower limbs, cardiovascular endurance and health-related quality of life during inpatient rehabilitation in intensive care unit acquired weakness. MATERIALS & METHODS: Thirty-nine patients with severe to moderate walking disability were enrolled in one of the three experimental groups: (a) ergometer training group, (b) resistance training group and (c) control group (standard care only). Intervention was applied 5 days a week over a 4-week period during inpatient neurological rehabilitation. We evaluated walking ability (Functional Ambulation Category test, timed up and go test, 10-metre walk test and 6-minute walk test), muscle strength (Medical Research Council and maximum muscle strength tests), cardiovascular endurance and muscular endurance of the lower limbs at the fatigue threshold (physical working capacity at fatigue threshold) and quality of life (medical outcomes study SF-36 form). All tests were performed at baseline, after two weeks of treatment and at the end of the 4-week intervention period. RESULTS: Ergometer training and resistance training enhanced the effectiveness of standard care in order to improve (a) lower limb muscle strength, (b) walking ability and (c) cardiorespiratory fitness during inpatient rehabilitation of intensive care acquired weakness. In addition, ergometer training may be superior to resistance training. CONCLUSIONS: Our data encourage more research to develop and implement these training tools in rehabilitation programmes for intensive care acquired weakness.

The Relationship among Cognition, Psychological Well-being, Physical Activity and Demographic Data in People over 80 Years of Age.

Objectives: It is the main goal of this study to investigate the relationships between physical abilities, cognitive abilities and the aspects of psychological well-being in people aged 80 or older. In contrast to other studies, we focus on the executive functions and mental rotation while investigating cognitive performance; this is because it is well known in the literature investigating younger participants that these functions relate to some kind of motor or physical activity. Methods: 41 independently living persons over 80 years were enrolled. Physical activities (German Physical Activity Questionnaire 50+), balance (One leg stand), psychological well-being (Resilience, General depressions scale), cognitive abilities (Flanker task, Mental rotation, Number connection test) as well as the influence of gender and education status were analyzed. Results: Higher physical activity correlates with higher resilience. Persons with higher education and men show better values on the depression scale. Better mental rotation ability could be detected in persons with higher education. Discussion: This first experimental study with people only over 80 years demonstrates the importance of education and physical activity for different aspects of psychological well-being. Due to the aim of investigating participants only over 80 years living independently the sample size is small so the study should be further enlarged.

Motor Recovery of the Affected Hand in Subacute Stroke Correlates with Changes of Contralesional Cortical Hand Motor Representation.

Objective. To investigate the relationship between changes of cortical hand motor representation and motor recovery of the affected hand in subacute stroke. Methods. 17 patients with motor impairment of the affected hand were enrolled in an in-patient neurological rehabilitation program. Hand motor function tests (Wolf Motor Function Test, Action Research Arm Test) and neurophysiological evaluations (resting motor threshold, motor evoked potentials, motor map area size, motor map area volume, and motor map area location) were obtained from both hands and hemispheres at baseline and two, four, and six weeks of in-patient rehabilitation. Results. There was a wide spectrum of hand motor impairment at baseline and hand motor recovery over time. Hand motor function and recovery correlated significantly with (i) reduction of cortical excitability, (ii) reduction in size and volume of cortical hand motor representation, and (iii) a medial and anterior shift of the center of gravity of cortical hand motor representation within the contralesional hemisphere. Conclusion. Recovery of motor function of the affected hand after stroke is accompanied by definite changes in excitability, size, volume, and location of hand motor representation over the contralesional primary motor cortex. These measures may serve as surrogate markers for the outcome of hand motor rehabilitation after stroke.

Direct Current Stimulation over the Primary Motor Cortex, Cerebellum, and Spinal Cord to Modulate Balance Performance: A Randomized Placebo-Controlled Trial.

OBJECTIVES: Existing applications of non-invasive brain stimulation in the modulation of balance ability are focused on the primary motor cortex (M1). It is conceivable that other brain and spinal cord areas may be comparable or more promising targets in this regard. This study compares transcranial direct current stimulation (tDCS) over (i) the M1, (ii) the cerebellum, and (iii) trans-spinal direct current stimulation (tsDCS) in the modulation of balance ability. METHODS: Forty-two sports students were randomized in this placebo-controlled study. Twenty minutes of anodal 1.5 mA t/tsDCS over (i) the M1, (ii) the cerebellum, and (iii) the spinal cord, as well as (iv) sham tDCS were applied to each subject. The Y Balance Test, Single Leg Landing Test, and Single Leg Squat Test were performed prior to and after each intervention. RESULTS: The Y Balance Test showed significant improvement after real stimulation of each region compared to sham stimulation. While tsDCS supported the balance ability of both legs, M1 and cerebellar tDCS supported right leg stand only. No significant differences were found in the Single Leg Landing Test and the Single Leg Squat Test. CONCLUSIONS: Our data encourage the application of DCS over the cerebellum and spinal cord (in addition to the M1 region) in supporting balance control. Future research should investigate and compare the effects of different stimulation protocols (anodal or cathodal direct current stimulation (DCS), alternating current stimulation (ACS), high-definition DCS/ACS, closed-loop ACS) over these regions in healthy people and examine the potential of these approaches in the neurorehabilitation.

Non-Invasive Brain Stimulation and Sex/Polypeptide Hormones in Reciprocal Interactions: A Systematic Review.

A better understanding of interindividual differences and the development of targeted therapies is one of the major challenges of modern medicine. The sex of a person plays a crucial role in this regard. This systematic review aimed to summarise and analyse available evidence on the mutual interactions between non-invasive brain stimulation and sex/polypeptide hormones. The PubMed database was searched from its inception to 31 March 2023, for (i) studies that investigated the impact of sex and/or polypeptide hormones on the effects induced by non-invasive brain stimulation, or (ii) studies that investigated non-invasive brain stimulation in the modulation of sex and/or polypeptide hormones. Eighteen studies (319 healthy and 96 disabled participants) were included. Most studies focused on female sex hormone levels during the menstrual cycle. The later follicular phase is associated with a weak between hemispheric and intracortical inhibition, strong intracortical facilitation, and high stimulation-induced neural and behavioural changes. The opposite effects are observed during the luteal phase. In addition, the participant's sex, presence and/or absence of real ovulation and increase in oestradiol level by chorionic gonadotropin injection influence the stimulation-induced neurophysiological and behavioural effects. In Parkinson's disease and consciousness disorders, the repetitive application of non-invasive brain stimulation increases oestradiol and dehydroepiandrosterone levels and reduces disability. To date, male hormones have not been sufficiently included in these studies. Here, we show that the sex and/or polypeptide hormones and non-invasive brain stimulation methods are in reciprocal interactions. This may be used to create a more effective and individualised approach for healthy individuals and individuals with disabilities.

Hemispheric Differences of 1 Hz rTMS over Motor and Premotor Cortex in Modulation of Neural Processing and Hand Function.

INTRODUCTION: Non-invasive brain stimulation can modulate both neural processing and behavioral performance. Its effects may be influenced by the stimulated area and hemisphere. In this study (EC no. 09083), repetitive transcranial magnetic stimulation (rTMS) was applied to the primary motor cortex (M1) or dorsal premotor cortex (dPMC) of either the right or left hemisphere, while evaluating cortical neurophysiology and hand function. METHODS: Fifteen healthy subjects participated in this placebo-controlled crossover study. Four sessions of real 1 Hz rTMS (110% of rMT, 900 pulses) over (i) left M1, (ii) right M1, (iii) left dPMC, (iv) right dPMC, and one session of (v) placebo 1 Hz rTMS (0% of rMT, 900 pulses) over the left M1 were applied in randomized order. Motor function of both hands (Jebsen-Taylor Hand Function Test (JTHFT)) and neural processing within both hemispheres (motor evoked potentials (MEPs), cortical silent period (CSP), and ipsilateral silent period (ISP)) were evaluated prior and after each intervention session. RESULTS: A lengthening of CSP and ISP durations within the right hemisphere was induced by 1 Hz rTMS over both areas and hemispheres. No such intervention-induced neurophysiological changes were detected within the left hemisphere. Regarding JTHFT and MEP, no intervention-induced changes ensued. Changes of hand function correlated with neurophysiological changes within both hemispheres, more often for the left than the right hand. CONCLUSIONS: Effects of 1 Hz rTMS can be better captured by neurophysiological than behavioral measures. Hemispheric differences need to be considered for this intervention.

Does anodal tDCS improve basketball performance? A randomized controlled trial.

Shooting precision as well as dribbling and agility are crucial components of performance in basketball. We examined the effects of anodal tDCS over the dominant primary motor cortex in supporting these basketball specific abilities. Fifty-two sports students were enrolled in a double-blind, randomized, placebo-controlled, crossover trial with two interventions. Twenty minutes of anodal 1 mA tDCS/sham tDCS were applied over the primary motor cortex of the dominant hemisphere. Basketball shooting precision (basketball shooting accuracy test) and basketball specific dribbling and agility (Illinois ball-dribbling test) were tested prior and after each intervention. Basketball shooting precision and basketball specific dribbling and agility improved after real tDCS but not after sham tDCS. ANOVAs show significant intervention*time effects on both the shooting accuracy test (F1,51 = 5.6; P = 0.022) and on the Illinois ball-dribbling test (F1,51 = 4.5; P = 0.038). Anodal 1 mA tDCS over the dominant primary motor cortex is effective in supporting short-term performance in basketball. However, the available data is insufficient for application of this novel method within the framework of conventional sports training.

Is tDCS an Adjunct Ergogenic Resource for Improving Muscular Strength and Endurance Performance? A Systematic Review.

Exercise performance is influenced by many physical factors, such as muscle strength and endurance. Particularly in the physical fitness and sports performance contexts, there are many types of ergogenic aids to improve muscular strength and endurance performance, with non-athletes and even athletes using illegal drugs to reach the top. Thus, the development of innovative methods to aid in exercise performance is of great interest. One such method is transcranial direct current stimulation (tDCS). A systematic search was performed on the following databases, until January 2019; PubMed/MEDLINE, SCOPUS, and Pedro database. Studies on tDCS for muscular strength and endurance performance improvement in non-athletes and athletes adults were included. We compared the effect of anodal-tDCS (a-tDCS) to a sham/control condition on the outcomes muscular strength and endurance performance. We found 26 controlled trials. No trial mentions negative side effects of the intervention. The data show differences between the studies investigating muscle strength and the studies evaluating endurance, with regard to successful use of tDCS. Studies investigating the efficiency of tDCS on improving muscular strength demonstrate positive effects of a-tDCS in 66.7% of parameters tested. In contrast, in studies evaluating the effects of a-tDCS on improving endurance performance the a-tDCS revealed a significant improvement in only 50% of parameters assessed. The majority of the data shows consistently influence of a-tDCS on muscular strength, but not to endurance performance. The results of this systematic review suggest that a-tDCS can improve muscular strength, but not to endurance performance.

Cortico-spinal excitability and hand motor recovery in stroke: a longitudinal study.

OBJECTIVE: To describe the relationship between changes of cortico-spinal excitability and motor recovery of the affected hand after stroke. METHODS: Eighteen hemiparetic stroke patients with a severe-to-mild upper limb motor impairment were randomized. Cortico-spinal excitability measures (resting motor thresholds and motor evoked potentials) obtained from a distal (abductor pollicis brevis) and proximal (biceps brachii) upper limb muscle were assessed for both hemispheres. Motor function of the affected hand was tested by the Wolf Motor Function and Action Research Arm tests. The evaluations were performed at baseline and weekly over 7 weeks of in-patient neurological rehabilitation. RESULTS: Severe hand dysfunction was associated with a strong suppression of ipsilesional cortico-spinal excitability and a shift of excitability towards the contralesional hemisphere. Mild hand impairment was associated with a shift of cortico-spinal excitability towards the ipsilesional hemisphere. Favorable motor recovery correlated with an increase of ipsilesional cortico-spinal excitability.