scholarly journals Non-Invasive Brain Stimulation to Investigate Language Production in Healthy Speakers: A Meta-Analysis

2017 ◽  
Author(s):  
Jana Klaus ◽  
Dennis J.L.G. Schutter
Keyword(s):  
Healthy Volunteers ◽  
Brain Stimulation ◽  
Language Production ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Language Functioning ◽  
Non Invasive ◽  
Control Target ◽  
The Brain ◽  
Healthy Participants

Non-invasive brain stimulation (NIBS) has become a common method to study the interrelations between the brain and language functioning. This meta-analysis examined the efficacy of transcranial magnetic stimulation (TMS) and direct current stimulation (tDCS) in the study of language production in healthy volunteers. Forty-five effect sizes from 30 studies which investigated the effects of NIBS on picture naming or verbal fluency in healthy participants were meta-analysed. Further sub-analyses investigated potential influences of stimulation type, control, target site, task, online vs. offline application, and current density of the target electrode. Random effects modelling showed a small, but reliable effect of NIBS on language production. Subsequent analyses indicated larger weighted mean effect sizes for TMS as compared to tDCS studies. No statistical differences for the other sub-analyses were observed. We conclude that NIBS is a useful method for neuroscientific studies on language production in healthy volunteers.

scholarly journals The effect of ketamine on psychopathology and implications for understanding schizophrenia and its therapeutic use: a meta-analysis

BJPsych Open ◽  
2021 ◽  
Vol 7 (S1) ◽  
pp. S237-S237
Author(s):  
Katherine Beck ◽  
Guy Hindley ◽  
Faith Borgan ◽  
Cedric Ginestet ◽  
Robert McCutcheon ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Negative Symptoms ◽  
Rating Scale ◽  
Meta Analysis ◽  
Therapeutic Use ◽  
Effect Sizes ◽  
Psychotic Symptoms ◽  
Positive Symptoms ◽  
Placebo Condition ◽  
Healthy Participants

AimsTo conduct a meta-analysis of the effect of ketamine on psychopathology in healthy volunteers and patients with schizophrenia, and the experimental factors affecting this.BackgroundKetamine is increasingly used to treat depression and other psychiatric disorders but can induce schizophrenia-like symptoms. Despite this, the consistency and magnitude of symptoms induced by ketamine, or what factors influence the effects of ketamine on these remain unknown.MethodMEDLINE, EMBASE and PsychINFO databases were searched for within-subject placebo controlled studies reporting symptoms using the Brief Psychiatric Rating Scale (BPRS) or Positive and Negative Syndrome Scale (PANSS) in response to an acute ketamine challenge in healthy participants or people with schizophrenia. Two independent investigators extracted study-level data for a random-effects meta-analysis. Total, positive and negative BPRS and PANSS scores were extracted. Sub-group analyses were conducted examining the effect of: blinding status, ketamine preparation, infusion method and time between ketamine and placebo condition. Standardized mean change scores were used as effect sizes for individual studies. Standardized mean changes between ketamine and placebo for total, positive and negative BPRS and PANSS were calculated.ResultOf 7819 citations retrieved, 36 studies involving healthy participants were included. The overall sample included 725 healthy volunteers exposed to both the ketamine and placebo condition. Ketamine induced a significant increase in transient psychopathology in healthy participants, for total (Standardized mean change (SMC) = 1.50 (95% CI = 1.23 to 1.77), p < 0.0001), positive (SMC = 1.55 (95% CI = 1.29 to 1.81), p < 0.0001) and negative (SMC = 1.16, (95% CI = 0.96 to 1.35), p < 0.0001) symptom ratings, relative to the placebo condition. This effect was significantly greater for positive symptoms than negative symptoms (p = 0.004). Bolus followed by constant infusion increased ketamine's effect on positive symptoms relative to infusion alone (p = 0.006). Single-day study design increased ketamine's effect on total symptoms (p = 0.007), but age and gender did not moderate effects. There were insufficient studies for meta-analysis of studies in schizophrenia. Of these studies, two found a significant increase in symptoms with ketamine administration in total and positive symptoms. Only one study found an increase in negative symptom severity with ketamine.ConclusionThese findings show that acute ketamine administration induces schizophrenia-like symptomatology with large effect sizes but there is a greater increase in positive than negative symptoms, and when a bolus is used. These findings suggest bolus doses should be avoided in its therapeutic use to minimize the risk of inducing transient positive psychotic symptoms.

scholarly journals Effects of non-invasive brain stimulation in dystonia: a systematic review and meta-analysis

2021 ◽  
Author(s):  
Jordan Morrison-Ham ◽  
Gillian M Clark ◽  
Elizabeth G Ellis ◽  
Andris Cerins ◽  
Juho Joutsa ◽  
...  
Keyword(s):  
Brain Stimulation ◽  
Effect Size ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Future Research ◽  
Motor Training ◽  
Intraoperative Bleeding ◽  
Non Invasive ◽  
Small Effect Size ◽  
Deep Brain

Background. Deep brain stimulation is a highly effective treatment of dystonia, but is invasive and associated with risks, such as intraoperative bleeding and infections. Previous research has used non-invasive brain stimulation (NIBS) in an attempt to alleviate symptoms of dystonia. The results of these studies, however, have been variable, leaving efficacy unclear. This study aimed to evaluate the effects of NIBS on symptoms of dystonia and determine whether methodological characteristics are associated with variability in effect size. Methods. Embase and MEDLINE Complete databases were searched for articles using any type of NIBS as an intervention in dystonia patients, with changes in dystonia symptoms the primary outcome of interest. Results. Meta-analysis of 26 studies demonstrated a small effect size for NIBS in reducing symptoms of dystonia (random-effects Hedges' g = 0.21, p = .002). Differences in the type of NIBS, type of dystonia, and brain region stimulated had a significant effect on dystonia symptoms. Meta-regression revealed that 10 sessions of active stimulation, and the application of concurrent motor training programs resulted in significantly larger mean effect sizes. Conclusion. NIBS has yielded small improvements to dystonic symptoms, but effect sizes depended on methodological characteristics, with more sessions of stimulation producing a larger response. Future research should further investigate the application of NIBS parallel to motor training, in addition to providing a greater quantity of sessions, to help define optimal parameters for NIBS protocols in dystonia. Registration. PROSPERO 2020, CRD42020175944

scholarly journals Does non-invasive brain stimulation modify hand dexterity? Protocol for a systematic review and meta-analysis

BMJ Open ◽  
2017 ◽  
Vol 7 (6) ◽  
pp. e015669 ◽  
Author(s):  
Anthony Terrence O'Brien ◽  
Gabriel Torrealba Acosta ◽  
Rodrigo Huerta ◽  
Aurore Thibaut
Keyword(s):  
Systematic Review ◽  
Brain Stimulation ◽  
Meta Analysis ◽  
Non Invasive ◽  
Hand Dexterity

scholarly journals Minor Physical Anomalies in Bipolar Disorder—A Meta-Analysis

2021 ◽  
Vol 12 ◽  
Author(s):  
Eszter Varga ◽  
András Hajnal ◽  
Alexandra Soós ◽  
Péter Hegyi ◽  
Dóra Kovács ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Meta Analysis ◽  
Bipolar Disorders ◽  
Effect Sizes ◽  
Inclusion Criteria ◽  
Weighted Mean ◽  
Quality Of Evidence ◽  
Minor Physical Anomalies ◽  
The Brain

Introduction: Minor physical anomalies (MPAs) may reflect basic neurobiological features underlying bipolar disorders (BPD), as they are sensitive physical indicators of morphogenetic failure of the brain. Despite several researches about the presence of MPAs in BPD, the results are still controversial.Objectives: The aim of the present meta-analysis was to assess the standardized weighted mean effect sizes of MPAs in BPD and to examine if MPAs may be found predominantly in the head and/or facial regions in BPD patients compared to controls (HC).Methods: Four studies, involving 155 patients with BPD, and 187 HC, were involved in the analysis after searching the literature. For the investigation of MPAs in the peripheral (MPA-P) and in the head and facial regions (MPA-CF), two studies involving 121 BPD patients, and 133 HC passed the inclusion criteria.Results: The number of the MPAs in the BPD group was significantly higher compared to HC. Another important finding of the present study is that BPD patients' MPA-P scores do not significantly differ from those of the HC. In contrast, BPD patients' MPA-CF scores were found to be significantly higher compared to HC subjects. It is important to note that there was a low number of eligible publications included, which caused higher heterogeneity.Conclusions: Low quality of evidence suggests that MPAs are more common in patients with BPD than in HC and the higher rate of MPAs is found predominantly in the head and facial regions.

scholarly journals Does non-invasive vagus nerve stimulation affect heart rate variability? A living and interactive Bayesian meta-analysis

2021 ◽  
Author(s):  
Vinzent Wolf ◽  
Anne Kühnel ◽  
Vanessa Teckentrup ◽  
Julian Koenig ◽  
Nils B. Kroemer
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Vagus Nerve ◽  
Brain Stimulation ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Meta Analysis ◽  
Current Evidence ◽  
Beneficial Effects ◽  
Non Invasive

AbstractNon-invasive brain stimulation techniques, such as transcutaneous auricular vagus nerve stimulation (taVNS), have considerable potential for clinical use. Beneficial effects of taVNS have been demonstrated on symptoms in patients with mental or neurological disorders as well as transdiagnostic dimensions, including mood and motivation. However, since taVNS research is still an emerging field, the underlying neurophysiological processes are not yet fully understood, and the replicability of findings on biomarkers of taVNS effects has been questioned. Here, we perform a living Bayesian random effects meta-analysis to synthesize the current evidence concerning the effects of taVNS on heart rate variability (HRV), a candidate biomarker that has, so far, received most attention in the field. To keep the synthesis of evidence transparent and up to date as new studies are being published, we developed a Shiny web app that regularly incorporates new results and enables users to modify study selection criteria to evaluate the robustness of the inference across potential confounds. Our analysis focuses on 17 single-blind studies comparing taVNS versus sham in healthy participants. These newly synthesized results provide strong evidence for the null hypothesis (g = 0.011, CIshortest = [−0.103, 0.125], BF01 = 25.587), indicating that acute taVNS does not alter HRV compared to sham. To conclude, based on a synthesis of the available evidence to date, there is no support for the hypothesis that HRV is a robust biomarker for acute taVNS. By increasing transparency and timeliness, we believe that the concept of living meta-analyses can lead to transformational benefits in emerging fields such as non-invasive brain stimulation.

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