-
Reviews in the Neurosciences Feb 2018Noninvasive brain stimulation (NIBS) modifies corticospinal excitability (CSE) historically in a predictable manner dependent on stimulation parameters. Researchers,... (Meta-Analysis)
Meta-Analysis Review
Biological and anatomical factors influencing interindividual variability to noninvasive brain stimulation of the primary motor cortex: a systematic review and meta-analysis.
Noninvasive brain stimulation (NIBS) modifies corticospinal excitability (CSE) historically in a predictable manner dependent on stimulation parameters. Researchers, however, discuss high degrees of variability between individuals, either responding as expected or not responding as expected. The explanation for this interindividual variability remains unknown with suggested interplay between stimulation parameters and variations in biological, anatomical, and physiological factors. This systematic review and meta-analysis aimed to investigate the effect of variation in inherent factors within an individual (biological and anatomical factors) on CSE in response to NIBS of the primary motor cortex. Twenty-two studies were included investigating genetic variation (n=7), age variation (n=4), gender variation (n=7), and anatomical variation (n=5). The results indicate that variation in brain-derived neurotrophic factor genotypes may have an effect on CSE after NIBS. Variation between younger and older adults also affects CSE after NIBS. Variation between age-matched males and females does not affect CSE after NIBS, but variation across the menstrual cycle does. Variation between skull thickness and brain tissue morphology influences the electric field magnitude that ultimately reaches the primary motor cortex. These findings indicate that biological and anatomical variations may in part account for interindividual variability in CSE in response to NIBS of the primary motor cortex, categorizing individuals as responding as expected (responders) or not responding as expected (nonresponders).
Topics: Brain-Derived Neurotrophic Factor; Humans; Individuality; Motor Cortex; Neuronal Plasticity; Surveys and Questionnaires; Transcranial Magnetic Stimulation
PubMed: 29055940
DOI: 10.1515/revneuro-2017-0048 -
Frontiers in Neurology 2021During recovery from stroke, the contralesional motor cortex (M1) may undergo maladaptive changes that contribute to impaired interhemispheric inhibition (IHI)....
Does Cathodal vs. Sham Transcranial Direct Current Stimulation Over Contralesional Motor Cortex Enhance Upper Limb Motor Recovery Post-stroke? A Systematic Review and Meta-analysis.
During recovery from stroke, the contralesional motor cortex (M1) may undergo maladaptive changes that contribute to impaired interhemispheric inhibition (IHI). Transcranial direct current stimulation (tDCS) with the cathode over contralesional M1 may inhibit this maladaptive plasticity, normalize IHI, and enhance motor recovery. The objective of this systematic review and meta-analysis was to evaluate available evidence to determine whether cathodal tDCS on contralesional M1 enhances motor re-learning or recovery post-stroke more than sham tDCS. We searched OVID Medline, Embase, and the Cochrane Central Register of Controlled Trials for participants with stroke (>1 week post-onset) with motor impairment and who received cathodal or sham tDCS to contralesional M1 for one or more sessions. The outcomes included a change in any clinically validated assessment of physical function, activity, or participation, or a change in a movement performance variable (., time, accuracy). A meta-analysis was performed by pooling five randomized controlled trials (RCTs) and comparing the change in Fugl-Meyer upper extremity scores between cathodal and sham tDCS groups. Eleven studies met the inclusion criteria. Qualitatively, four out of five cross-over design studies and three out of six RCTs reported a significant effect of cathodal vs. sham tDCS. In the quantitative synthesis, cathodal tDCS ( = 65) did not significantly reduce motor impairment compared to sham tDCS ( = 67; standardized mean difference = 0.33, = 1.79, = 0.07) with a little observed heterogeneity ( = 5%). The effects of cathodal tDCS to contralesional M1 on motor recovery are small and consistent. There may be sub-populations that may respond to this approach; however, further research with larger cohorts is required.
PubMed: 33935936
DOI: 10.3389/fneur.2021.626021 -
Neuropsychologia Jan 2023TDCS is one of the most commonly used methods among studies with transcranial electrical stimulation and motor skills learning. Differences between study results suggest... (Review)
Review
TDCS is one of the most commonly used methods among studies with transcranial electrical stimulation and motor skills learning. Differences between study results suggest that the effect of tDCS on motor learning is dependent on the motor task performed or on the tDCS assembly specification used in the learning process. This systematic review aimed to analyze the tDCS effect on motor learning and verify whether this effect is dependent on the task or tDCS assembly specifications. Searches were performed in PubMed, SciELO, LILACS, Web of Science, CINAHL, Scopus, SPORTDiscus, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and PsycINFO. Articles were included that analyzed the effect of tDCS on motor learning through pre-practice, post-practice, retention, and/or transfer tests (period ≥24 h). The tDCS was most frequently applied to the primary motor cortex (M1) or the cerebellar cortex (CC) and the majority of studies found significant stimulation effects. Studies that analyzed identical or similar motor tasks show divergent results for the tDCS effect, even when the assembly specifications are the same. The tDCS effect is not dependent on motor task characteristics or tDCS assembly specifications alone but is dependent on the interaction between these factors. This interaction occurs between uni and bimanual tasks with anodal uni and bihemispheric (bilateral) stimulations at M1 or with anodal unihemispheric stimulations (unilateral and centrally) at CC, and between tasks of greater or lesser difficulty with single or multiple tDCS sessions. Movement time seems to be more sensitive than errors to indicate the effects of tDCS on motor learning, and a sufficient amount of motor practice to reach the "learning plateau" also seems to determine the effect of tDCS on motor learning.
Topics: Humans; Transcranial Direct Current Stimulation; Motor Cortex; Learning; Motor Skills; Movement
PubMed: 36567006
DOI: 10.1016/j.neuropsychologia.2022.108463 -
Frontiers in Neuroscience 2021This systematic review aims to examine the efficacy of transcranial direct current stimulation (tDCS) combined with physical training on the excitability of the motor...
Effects of Transcranial Direct Current Stimulation Combined With Physical Training on the Excitability of the Motor Cortex, Physical Performance, and Motor Learning: A Systematic Review.
This systematic review aims to examine the efficacy of transcranial direct current stimulation (tDCS) combined with physical training on the excitability of the motor cortex, physical performance, and motor learning. A systematic search was performed on PubMed, Web of Science, and EBSCO databases for relevant research published from inception to August 2020. Eligible studies included those that used a randomized controlled design and reported the effects of tDCS combined with physical training to improve motor-evoked potential (MEP), dynamic posture stability index (DPSI), reaction time, and error rate on participants without nervous system diseases. The risk of bias was assessed by the Cochrane risk of bias assessment tool. Twenty-four of an initial yield of 768 studies met the eligibility criteria. The risk of bias was considered low. Results showed that anodal tDCS combined with physical training can significantly increase MEP amplitude, decrease DPSI, increase muscle strength, and decrease reaction time and error rate in motor learning tasks. Moreover, the gain effect is significantly greater than sham tDCS combined with physical training. tDCS combined with physical training can effectively improve the excitability of the motor cortex, physical performance, and motor learning. The reported results encourage further research to understand further the synergistic effects of tDCS combined with physical training.
PubMed: 33897361
DOI: 10.3389/fnins.2021.648354 -
The Cochrane Database of Systematic... Nov 2021Many infants born preterm develop bronchopulmonary dysplasia (BPD), with lung inflammation playing a role. Corticosteroids have powerful anti-inflammatory effects and... (Review)
Review
BACKGROUND
Many infants born preterm develop bronchopulmonary dysplasia (BPD), with lung inflammation playing a role. Corticosteroids have powerful anti-inflammatory effects and have been used to treat individuals with established BPD. However, it is unclear whether any beneficial effects outweigh the adverse effects of these drugs.
OBJECTIVES
To examine the relative benefits and adverse effects of late (starting at seven or more days after birth) systemic postnatal corticosteroid treatment for preterm infants with evolving or established BPD.
SEARCH METHODS
We ran an updated search on 25 September 2020 of the following databases: CENTRAL via CRS Web and MEDLINE via OVID. We also searched clinical trials databases and reference lists of retrieved articles for randomised controlled trials (RCTs). We did not include quasi-RCTs.
SELECTION CRITERIA
We selected for inclusion in this review RCTs comparing systemic (intravenous or oral) postnatal corticosteroid treatment versus placebo or no treatment started at seven or more days after birth for preterm infants with evolving or established BPD. We did not include trials of inhaled corticosteroids.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methods. We extracted and analysed data regarding clinical outcomes that included mortality, BPD, and cerebral palsy. We used the GRADE approach to assess the certainty of evidence.
MAIN RESULTS
Use of the GRADE approach revealed that the certainty of evidence was high for most of the major outcomes considered, except for BPD at 36 weeks for all studies combined and for the dexamethasone subgroup, which were downgraded one level to moderate because of evidence of publication bias, and for the combined outcome of mortality or BPD at 36 weeks for all studies combined and for the dexamethasone subgroup, which were downgraded one level to moderate because of evidence of substantial heterogeneity. We included 23 RCTs (1817 infants); 21 RCTS (1382 infants) involved dexamethasone (one also included hydrocortisone) and two RCTs (435 infants) involved hydrocortisone only. The overall risk of bias of included studies was low; all were RCTs and most trials used rigorous methods. Late systemic corticosteroids overall reduce mortality to the latest reported age (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.66 to 0.99; 21 studies, 1428 infants; high-certainty evidence). Within the subgroups by drug, neither dexamethasone (RR 0.85, 95% CI 0.66 to 1.11; 19 studies, 993 infants; high-certainty evidence) nor hydrocortisone (RR 0.74, 95% CI 0.54 to 1.02; 2 studies, 435 infants; high-certainty evidence) alone clearly reduce mortality to the latest reported age. We found little evidence for statistical heterogeneity between the dexamethasone and hydrocortisone subgroups (P = 0.51 for subgroup interaction). Late systemic corticosteroids overall probably reduce BPD at 36 weeks' postmenstrual age (PMA) (RR 0.89, 95% CI 0.80 to 0.99; 14 studies, 988 infants; moderate-certainty evidence). Dexamethasone probably reduces BPD at 36 weeks' PMA (RR 0.76, 95% CI 0.66 to 0.87; 12 studies, 553 infants; moderate-certainty evidence), but hydrocortisone does not (RR 1.10, 95% CI 0.92 to 1.31; 2 studies, 435 infants; high-certainty evidence) (P < 0.001 for subgroup interaction). Late systemic corticosteroids overall probably reduce the combined outcome of mortality or BPD at 36 weeks' PMA (RR 0.85, 95% CI 0.79 to 0.92; 14 studies, 988 infants; moderate-certainty evidence). Dexamethasone probably reduces the combined outcome of mortality or BPD at 36 weeks' PMA (RR 0.75, 95% CI 0.67 to 0.84; 12 studies, 553 infants; moderate-certainty evidence), but hydrocortisone does not (RR 0.98, 95% CI 0.88 to 1.09; 2 studies, 435 infants; high-certainty evidence) (P < 0.001 for subgroup interaction). Late systemic corticosteroids overall have little to no effect on cerebral palsy (RR 1.17, 95% CI 0.84 to 1.61; 17 studies, 1290 infants; high-certainty evidence). We found little evidence for statistical heterogeneity between the dexamethasone and hydrocortisone subgroups (P = 0.63 for subgroup interaction). Late systemic corticosteroids overall have little to no effect on the combined outcome of mortality or cerebral palsy (RR 0.90, 95% CI 0.76 to 1.06; 17 studies, 1290 infants; high-certainty evidence). We found little evidence for statistical heterogeneity between the dexamethasone and hydrocortisone subgroups (P = 0.42 for subgroup interaction). Studies had few participants who were not intubated at enrolment; hence, it is not possible to make any meaningful comments on the effectiveness of late corticosteroids in preventing BPD in non-intubated infants, including those who might in the present day be supported by non-invasive techniques such as nasal continuous positive airway pressure or high-flow nasal cannula oxygen/air mixture, but who might still be at high risk of later BPD. Results of two ongoing studies are awaited.
AUTHORS' CONCLUSIONS
Late systemic postnatal corticosteroid treatment (started at seven days or more after birth) reduces the risks of mortality and BPD, and the combined outcome of mortality or BPD, without evidence of increased cerebral palsy. However, the methodological quality of studies determining long-term outcomes is limited, and no studies were powered to detect increased rates of important adverse long-term neurodevelopmental outcomes. This review supports the use of late systemic corticosteroids for infants who cannot be weaned from mechanical ventilation. The role of late systemic corticosteroids for infants who are not intubated is unclear and needs further investigation. Longer-term follow-up into late childhood is vital for assessment of important outcomes that cannot be assessed in early childhood, such as effects of late systemic corticosteroid treatment on higher-order neurological functions, including cognitive function, executive function, academic performance, behaviour, mental health, motor function, and lung function. Further RCTs of late systemic corticosteroids should include longer-term survival free of neurodevelopmental disability as the primary outcome.
Topics: Adrenal Cortex Hormones; Anti-Inflammatory Agents; Bronchopulmonary Dysplasia; Dexamethasone; Drug Administration Schedule; Glucocorticoids; Humans; Infant; Infant, Newborn; Infant, Premature
PubMed: 34758507
DOI: 10.1002/14651858.CD001145.pub5 -
PM & R : the Journal of Injury,... Feb 2021Transcranial direct current stimulation (tDCS) and functional electrical stimulation (FES) are two widely applied methods of electrical stimulation for motor recovery... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
Transcranial direct current stimulation (tDCS) and functional electrical stimulation (FES) are two widely applied methods of electrical stimulation for motor recovery among stroke patients. This systematic review and meta-analysis investigated the efficacy of tDCS and FES for strength production in stroke patients. TYPE: Systematic review.
LITERATURE SURVEY
Studies that explored the effects of tDCS or FES on the strength production of paralyzed muscles in stroke patients were retrieved on a comprehensive set of three databases: (1) Google Scholar, (2) PubMed, and (3) the Cochrane Database of Systematic Reviews until July 2019.
METHODOLOGY
Systematic study retrieval led to the inclusion of 15 studies that reported on strength production effects after tDCS and FES interventions among stoke patients. A sham control group and randomization were used in each study. The 15 studies included 20 comparisons with sham controls, 7 of which involved tDCS and 13 of which involved FES.
SYNTHESIS
Random-effects models showed that strength production was improved after tDCS (effect size [ES] = 0.52, 95% confidence interval [CI] = 0.35-0.69, P < .001, Z = 6.05) and FES (ES = 0.47, 95% CI = 0.16-0.78, P < .003, Z = 2.99). Additionally, tDCS was shown to improve strength production in the acute (ES = 0.52, 95% CI = 0.24-0.80, P < .001, Z = 3.65), subacute (ES = 0.85, 95% CI = 0.37-1.32, P < .001, Z = 3.51), but not chronic (ES = 0.06, 95% CI = -0.47-0.60, P = .82, Z = 0.23) phases of stroke recovery. Out of the 13 studies involving FES, 12 investigated strength production in the chronic phase and one investigated in the acute phase, showing a positive effect in these two stages.
CONCLUSIONS
The results of the meta-analysis showed that tDCS and FES successfully improved strength production in stroke patients.
Topics: Electric Stimulation; Humans; Motor Cortex; Muscles; Stroke; Stroke Rehabilitation; Transcranial Direct Current Stimulation
PubMed: 32385898
DOI: 10.1002/pmrj.12399 -
Scientific Reports Apr 2020Invasive motor Cortex Stimulation (iMCS) was introduced in the 1990's for the treatment of chronic neuropathic orofacial pain (CNOP), although its effectiveness remains... (Meta-Analysis)
Meta-Analysis
Invasive motor Cortex Stimulation (iMCS) was introduced in the 1990's for the treatment of chronic neuropathic orofacial pain (CNOP), although its effectiveness remains doubtful. However, CNOP is known to be a heterogeneous group of orofacial pain disorders, which can lead to different responses to iMCS. Therefore, this paper investigated (1) whether the effectiveness of iMCS is significantly different among different CNOP disorders and (2) whether other confounding factors can be impacting iMCS results in CNOP. A systematic review and meta-analysis using a linear mixed-model was performed. Twenty-three papers were included, totaling 140 CNOP patients. Heterogeneity of the studies showed to be 55.8%. A visual analogue scale (VAS) measured median pain relief of 66.5% (ranging from 0-100%) was found. Linear mixed-model analysis showed that patients suffering from trigeminal neuralgia responded significantly more favorable to iMCS than patients suffering from dysfunctional pain syndromes (p = 0.030). Also, patients suffering from CNOP caused by (supra)nuclear lesions responded marginally significantly better to iMCS than patients suffering from CNOP due to trigeminal nerve lesions (p = 0.049). No other confounding factors were elucidated. This meta-analysis showed that patients suffering from trigeminal neuralgia and patients suffering from (supra)nuclear lesions causing CNOP responded significantly more favorable than others on iMCS. No other confounding factors were found relevant.
Topics: Chronic Pain; Electric Stimulation Therapy; Facial Pain; Female; Humans; Male; Middle Aged; Motor Cortex; Neuralgia; Syndrome; Trigeminal Neuralgia
PubMed: 32346080
DOI: 10.1038/s41598-020-64177-z -
Clinical Neurophysiology : Official... Apr 2012The primary aim of this review is to evaluate the effects of anodal transcranial direct current stimulation (a-tDCS) on corticomotor excitability and motor function in... (Meta-Analysis)
Meta-Analysis Review
Does anodal transcranial direct current stimulation enhance excitability of the motor cortex and motor function in healthy individuals and subjects with stroke: a systematic review and meta-analysis.
The primary aim of this review is to evaluate the effects of anodal transcranial direct current stimulation (a-tDCS) on corticomotor excitability and motor function in healthy individuals and subjects with stroke. The secondary aim is to find a-tDCS optimal parameters for its maximal effects. Electronic databases were searched for studies into the effect of a-tDCS when compared to no stimulation. Studies which met the inclusion criteria were assessed and methodological quality was examined using PEDro and Downs and Black (D&B) assessment tools. Data from seven studies revealed increase in corticomotor excitability with a small but significant effect size (0.31 [0.14, 0.48], p=0.0003) in healthy subjects and data from two studies in subjects with stroke indicated significant results with moderate effect size (0.59 [0.24, 0.93], p=0.001) in favor of a-tDCS. Likewise, studies examining motor function demonstrated a small and non-significant effect (0.39 [-0.17, 0.94], p=0.17) in subjects with stroke and a large but non-significant effect (0.92 [-1.02, 2.87], p=0.35) in healthy subjects in favor of improvement in motor function. The results also indicate that efficacy of a-tDCS is dependent on current density and duration of application. A-tDCS increases corticomotor excitability in both healthy individuals and subjects with stroke. The results also show a trend in favor of motor function improvement following a-tDCS. A-tDCS is a non-invasive, cheap and easy-to-apply modality which could be used as a stand-alone technique or as an adds-on technique to enhance corticomotor excitability and the efficacy of motor training approaches. However, the small sample size of the included studies reduces the strength of the presented evidences and any conclusion in this regard should be considered cautiously.
Topics: Data Interpretation, Statistical; Electric Stimulation Therapy; Electrodes; Evoked Potentials, Motor; Humans; Motor Cortex; Movement Disorders; Psychomotor Performance; Publication Bias; Research Design; Stroke; Stroke Rehabilitation; Treatment Outcome
PubMed: 21978654
DOI: 10.1016/j.clinph.2011.08.029 -
Brain Sciences Apr 2022The purpose of this study was to quantify the effect of repetitive transcranial magnetic stimulation (rTMS), which is recommended for the improvement of some... (Review)
Review
The purpose of this study was to quantify the effect of repetitive transcranial magnetic stimulation (rTMS), which is recommended for the improvement of some pain-related symptoms and for antidepressant treatment, on the primary motor cortex (M1) in patients with fibromyalgia (FM). We searched for studies comparing rTMS and sham rTMS in the M1 of FM patients. Pain intensity, quality of life, health status, and depression were compared with or without rTMS for at least 10 sessions. We searched four databases. Quality assessment and quantitative analysis were performed using RevMan 5.4. After screening, five randomized controlled trials of 170 patients with FM were included in the analysis. As a result of the meta-analysis of rTMS on the M1 of individuals with FM, high-frequency rTMS resulted in a significant improvement on quality of life (MD = -2.50; 95% CI: -3.99 to -1.01) compared with sham rTMS. On the other hand, low-frequency rTMS resulted in a significant improvement on health status (MD = 15.02; 95% CI: 5.59 to 24.45). The application of rTMS to the M1 is proposed as an adjunctive measure in the treatment of individuals with FM. Because rTMS has various effects depending on each application site, it is necessary to classify sites or set frequencies as variables.
PubMed: 35624957
DOI: 10.3390/brainsci12050570 -
Pain Sep 2020One of the potential mechanisms of motor cortex stimulation by noninvasive brain stimulation (NIBS) effects on pain is through the restoration of the defective... (Meta-Analysis)
Meta-Analysis
One of the potential mechanisms of motor cortex stimulation by noninvasive brain stimulation (NIBS) effects on pain is through the restoration of the defective endogenous inhibitory pain pathways. However, there are still limited data on quantitative sensory testing (QST), including conditioned pain modulation (CPM), supporting this mechanism. This systematic review and meta-analysis aimed to evaluate the effects of noninvasive motor cortex stimulation on pain perception as indexed by changes in QST outcomes. Database searches were conducted until July 2019 to include randomized controlled trials that performed sham-controlled NIBS on the motor cortex in either the healthy and/or pain population and assessed the QST and CPM. Quality of studies was assessed through the Cochrane tool. We calculated the Hedge's effect sizes of QST and CPM outcomes and their 95% confidence intervals (95% CIs) and performed random-effects meta-analyses. Thirty-eight studies were included (1178 participants). We found significant increases of pain threshold in healthy subjects (ES = 0.16, 95% CI = 0.02-0.31, I2 = 22.2%) and pain populations (ES = 0.48, 95% CI = 0.15-0.80, I2 = 68.8%), and homogeneous higher CPM effect (pain ratings reduction) in healthy subjects (ES = -0.39, 95% CI = -0.64 to -0.14, I2 = 17%) and pain populations (ES = -0.35, 95% CI = -0.60 to -0.11, I2 = 0%) in the active NIBS group compared with sham. These results support the idea of top-down modulation of endogenous pain pathways by motor cortex stimulation as one of the main mechanisms of pain reduction assessed by QST, which could be a useful predictive and prognostic biomarker for chronic pain personalized treatment with NIBS.
Topics: Chronic Pain; Humans; Motor Cortex; Pain Management; Pain Measurement; Pain Threshold
PubMed: 32453135
DOI: 10.1097/j.pain.0000000000001893