Therapeutic and neurophysiologic aspects of transcranial magnetic stimulation in schizophrenia

The efficacy of transcranial magnetic stimulation (TMS) for negative symptoms in schizophrenia: a systematic review and meta-analysis

Several trials have shown preliminary evidence for the efficacy of transcranial magnetic stimulation (TMS) as a treatment for negative symptoms in schizophrenia. Here, we synthesize this literature in a systematic review and quantitative meta-analysis of double-blind randomized controlled trials of TMS in patients with schizophrenia. Specifically, MEDLINE, EMBASE, Web of Science, and PsycINFO were searched for sham-controlled, randomized trials of TMS among patients with schizophrenia. The effect of TMS vs. sham on negative symptoms in each study was quantified by the standardized mean difference (SMD, Cohen's d) with 95% confidence intervals (95%CI) and pooled across studies using an inverse variance random effects model. We identified 57 studies with a total of 2633 participants that were included in the meta-analysis. The pooled analysis showed statistically significant superiority of TMS (SMD = 0.41, 95%CI: 0.26; 0.56, p-value < 0.001), corresponding to a number needed to treat of 5. Furthermore, stratified analyses suggested that TMS targeting the left dorsolateral prefrontal cortex and using a stimulation frequency >1 Hz was most efficacious. There was, however, substantial heterogeneity and high risk of bias among the included studies. In conclusion, TMS appears to be an efficacious treatment option for patients with schizophrenia suffering from negative symptoms, but the optimal TMS parameters are yet to be established.

rTMS Reduces Psychopathological Burden and Cocaine Consumption in Treatment-Seeking Subjects With Cocaine Use Disorder: An Open Label, Feasibility Study

Introduction: Cocaine use disorder (CUD) currently represents a notable public health concern, linked with significant disability, high chances of chronicity, and lack of effective pharmacological or psychological treatments. Repetitive transcranial magnetic stimulation (rTMS) is supposed to be a potential therapeutic option for addictive disorders. Aim of this study was to evaluate the feasibility of rTMS on (1) cocaine craving and consumption and (2) other comorbid psychiatric symptoms. Methods: Twenty treatment seeking CUD subjects underwent 2 weeks of intensive rTMS treatment (15Hz; 5 days/week, twice a day for a total of 20 stimulation sessions) of the left dorsolateral prefrontal cortex, followed by 2 weeks of maintenance treatment (15Hz, 1 day/week, twice a day). Sixteen patients completed the study. Patients were evaluated at baseline (T0), after 2 weeks of treatment (T1), and at the end of the study (T2; 4 weeks), with the following scales: Cocaine Selective Severity Assessment (CSSA), Zung Self-Rating Anxiety Scale, Beck Depression Inventory (BDI), Symptom Checklist-90 (SCL-90), and the Insomnia Severity Index. Results: After four weeks of rTMS treatment, 9 out of 16 subjects (56.25%) had a negative urinalysis test, with a significant conversion rate with respect to baseline (Z = -3.00; p = 0.003). Craving scores significantly improved only at T2 (p = 0.020). The overall psychopathological burden, as measured by the SCL-90 Global Severity Index (GSI), significantly decreased during the study period (Z = -2.689; p = 0.007), with a relevant improvement with regards to depressive symptoms, anhedonia, and anxiety. Subjects exhibiting lower baseline scores on the SCL-90 were more likely to be in the positive outcome group at the end of the study (Z = -3.334; p = 0.001). Discussion: Findings from this study are consistent with previous contributions on rTMS use in subjects with cocaine use disorder. We evidenced a specific action on some psychopathological areas and a consequent indirect effect in terms of relapse prevention and craving reduction. A double-blind, sham-controlled, neuro-navigated rTMS study design is needed, in order to confirm the potential benefits of this technique, opening new scenarios in substance use disorders treatment.

Effects of low frequency rTMS treatment on brain networks for inner speech in patients with schizophrenia and auditory verbal hallucinations

INTRODUCTION

Efficacy of repetitive Transcranial Magnetic Stimulation (rTMS) targeting the temporo-parietal junction (TPJ) for the treatment of auditory verbal hallucinations (AVH) remains under debate. We assessed the influence of a 1Hz rTMS treatment on neural networks involved in a cognitive mechanism proposed to subserve AVH.

METHODS

Patients with schizophrenia (N=24) experiencing medication-resistant AVH completed a 10-day 1Hz rTMS treatment. Participants were randomized to active stimulation of the left or bilateral TPJ, or sham stimulation. The effects of rTMS on neural networks were investigated with an inner speech task during fMRI. Changes within and between neural networks were analyzed using Independent Component Analysis.

RESULTS

rTMS of the left and bilateral TPJ areas resulted in a weaker network contribution of the left supramarginal gyrus to the bilateral fronto-temporal network. Left-sided rTMS resulted in stronger network contributions of the right superior temporal gyrus to the auditory-sensorimotor network, right inferior gyrus to the left fronto-parietal network, and left middle frontal gyrus to the default mode network. Bilateral rTMS was associated with a predominant inhibitory effect on network contribution. Sham stimulation showed different patterns of change compared to active rTMS.

CONCLUSION

rTMS of the left temporo-parietal region decreased the contribution of the left supramarginal gyrus to the bilateral fronto-temporal network, which may reduce the likelihood of speech intrusions. On the other hand, left rTMS appeared to increase the contribution of functionally connected regions involved in perception, cognitive control and self-referential processing. These findings hint to potential neural mechanisms underlying rTMS for hallucinations but need corroboration in larger samples.

A systematic review and meta-analysis of the use of repetitive transcranial magnetic stimulation for auditory hallucinations treatment in refractory schizophrenic patients

BACKGROUND

The use of repetitive transcranial magnetic stimulation (rTMS) remains a promising therapeutic tool in the treatment of schizophrenia. Symptoms such as auditory hallucinations (AH) find contradictory results in many studies. Here we present an up-to-date systematic review and meta-analysis of rTMS in the treatment of AH in schizophrenia.

METHODS

We searched Pubmed-MEDLINE from 1999 to 2013 for double-blinded randomized sham-controlled trials that applied slow rTMS on the left temporoparietal cortex and assessed the outcome results using Hallucination Change Scale or Auditory Hallucination Rating Scale or Scale for Auditory Hallucinations (SAH). We identified 10 studies suitable for the meta-analysis.

RESULTS

We found a positive sized effect in favor of rTMS [random-effects model Hedges' g = 0.011, I-squared = 58.1%]. There was some variability between study effect sizes, but the sensitivity analysis concluded that none of them had sufficient weight to singularly alter the results of our meta-analysis.

DISCUSSION

rTMS appears to be an effective treatment for AH. The left temporoparietal cortex seems to be the area in which rTMS is effective. Although meta-analysis is a powerful analytical tool, more studies must be conducted in order to obtain a more expressive sample size to perform a more accurate analytical approach.

Repetitive transcranial magnetic stimulation for hallucination in schizophrenia spectrum disorders: A meta-analysis

OBJECTIVE

This study assessed the efficacy and tolerability of repetitive transcranial magnetic stimulation for treatment of auditory hallucination of patients with schizophrenia spectrum disorders.

DATA SOURCES

Online literature retrieval was conducted using PubMed, ISI Web of Science, EMBASE, Medline and Cochrane Central Register of Controlled Trials databases from January 1985 to May 2012. Key words were "transcranial magnetic stimulation", "TMS", "repetitive transcranial magnetic stimulation", and "hallucination".

STUDY SELECTION

Selected studies were randomized controlled trials assessing therapeutic efficacy of repetitive transcranial magnetic stimulation for hallucination in patients with schizophrenia spectrum disorders. Experimental intervention was low-frequency repetitive transcranial magnetic stimulation in left temporoparietal cortex for treatment of auditory hallucination in schizophrenia spectrum disorders. Control groups received sham stimulation.

MAIN OUTCOME MEASURES

The primary outcome was total scores of Auditory Hallucinations Rating Scale, Auditory Hallucination Subscale of Psychotic Symptom Rating Scale, Positive and Negative Symptom Scale-Auditory Hallucination item, and Hallucination Change Scale. Secondary outcomes included response rate, global mental state, adverse effects and cognitive function.

RESULTS

Seventeen studies addressing repetitive transcranial magnetic stimulation for treatment of schizophrenia spectrum disorders were screened, with controls receiving sham stimulation. All data were completely effective, involving 398 patients. Overall mean weighted effect size for repetitive transcranial magnetic stimulation versus sham stimulation was statistically significant (MD = -0.42, 95%CI: -0.64 to -0.20, P = 0.000 2). Patients receiving repetitive transcranial magnetic stimulation responded more frequently than sham stimulation (OR = 2.94, 95%CI: 1.39 to 6.24, P = 0.005). No significant differences were found between active repetitive transcranial magnetic stimulation and sham stimulation for positive or negative symptoms. Compared with sham stimulation, active repetitive transcranial magnetic stimulation had equivocal outcome in cognitive function and commonly caused headache and facial muscle twitching.

CONCLUSION

Repetitive transcranial magnetic stimulation is a safe and effective treatment for auditory hallucination in schizophrenia spectrum disorders.

Repetitive transcranial magnetic stimulation in psychiatry

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive and relatively painless tool that has been used to study various cognitive functions as well as to understand the brain–behavior relationship in normal individuals as well as in those with various neuropsychiatric disorders. It has also been used as a therapeutic tool in various neuropsychiatric disorders because of its ability to specifically modulate distinct brain areas. Studies have shown that repeated stimulation at low frequency produces long-lasting inhibition, which is called as long-term depression, whereas repeated high-frequency stimulation can produce excitation through long-term potentiation. This paper reviews the current status of rTMS as an investigative and therapeutic modality in various neuropsychiatric disorders. It has been used to study the cortical and subcortical functions, neural plasticity and brain mapping in normal individuals and in various neuropsychiatric disorders. rTMS has been most promising in the treatment of depression, with an overall milder adverse effect profile compared with electroconvulsive therapy. In other neuropsychiatric disorders such as schizophrenia, mania, epilepsy and substance abuse, it has been found to be useful, although further studies are required to establish therapeutic efficacy. It appears to be ineffective in the treatment of obsessive compulsive disorder. There is a paucity of studies of efficacy and safety of rTMS in pediatric and geriatric population. Although it appears safe, further research is required to optimize its efficacy and reduce the side-effects. Magnetic seizure therapy, which involves producing seizures akin to electroconvulsive therapy, appears to be of comparable efficacy in the treatment of depression with less cognitive adverse effects.

Repetitive transcranial magnetic stimulation for refractory symptoms in schizophrenia

PURPOSE OF REVIEW

Schizophrenia is an illness associated with a substantial degree of treatment resistance and suboptimal therapeutic response. In recent years, novel brain stimulation technologies have been identified as potential treatments for schizophrenia and related disorders. Several published studies have assessed the use of repetitive transcranial magnetic stimulation (rTMS) in patients with schizophrenia.

RECENT FINDINGS

Most published studies have focused on the use of low-frequency rTMS to treat refractory auditory hallucinations. These studies support the efficacy of stimulation over the temporoparietal cortex. Several other studies have assessed high-frequency stimulation of the prefrontal cortex in the treatment of negative symptoms. Novel protocols to treat auditory hallucinations have been piloted and case reports are emerging on the use of maintenance rTMS to treat auditory hallucinations.

SUMMARY

Overall, rTMS studies have demonstrated some promise in the treatment of schizophrenia. However, more research is required to delineate the role of this technique in clinical practice and to explore novel stimulation techniques that may ultimately lead to improved therapeutic efficacy.

Repetitive transcranial magnetic stimulation for the treatment of negative symptoms in residual schizophrenia: rationale and design of a sham-controlled, randomized multicenter study

Current meta-analysis revealed small, but significant effects of repetitive transcranial magnetic stimulation (rTMS) on negative symptoms in patients with schizophrenia. There is a need for further controlled, multicenter trials to assess the clinical efficacy of rTMS on negative symptoms in schizophrenia in a larger sample of patients. The objective of this multicenter, randomized, sham-controlled, rater- and patient-blind clinical trial is to investigate the efficacy of 3-week 10-Hz high frequency rTMS add on to antipsychotic therapy, 15 sessions per 3 weeks, 1,000 stimuli per session, stimulation intensity 110% of the individual motor threshold) of the left dorsolateral prefrontal cortex for treating negative symptoms in schizophrenia, and to evaluate the effect during a 12 weeks of follow-up. The primary efficacy endpoint is a reduction of negative symptoms as assessed by the negative sum score of the positive and negative symptom score (PANSS). A sample size of 63 in each group will have 80% power to detect an effect size of 0.50. Data analysis will be based on the intention to treat population. The study will be conducted at three university hospitals in Germany. This study will provide information about the efficacy of rTMS in the treatment of negative symptoms. In addition to psychopathology, other outcome measures such as neurocognition, social functioning, quality of life and neurobiological parameters will be assessed to investigate basic mechanisms of rTMS in schizophrenia. Main limitations of the trial are the potential influence of antipsychotic dosage changes and the difficulty to ensure adequate blinding.

The value of neuronavigated rTMS for the treatment of depression

Repetitive transcranial magnetic stimulation (rTMS) has been increasingly evaluated as a therapeutic tool for the treatment of depression, using various stimulation parameters and protocols. Heterogeneous results have been reported with regard to clinical outcome, at least partly due to the variety of procedures for coil placement above the desired site of stimulation. This article reviews the strategies for coil positioning in the treatment of depression. Considering preliminary clinical evidence, neuronavigated rTMS appears desirable to treat depression, compared to the standard targeting procedure (5cm anterior to the motor cortex). Coil positioning strategy might improve in the future by taking into consideration the individual abnormalities revealed by functional neuroimaging data.

Meta-analysis of the effects of repetitive transcranial magnetic stimulation (rTMS) on negative and positive symptoms in schizophrenia

BACKGROUND

A growing body of evidence suggests that repetitive transcranial magnetic stimulation (rTMS) can alleviate negative and positive symptoms of refractory schizophrenia. However, trials to date have been small and results are mixed.

METHODS

We performed meta-analyses of all prospective studies of the therapeutic application of rTMS in refractory schizophrenia assessing the effects of high-frequency rTMS to the left dorsolateral prefrontal cortex (DLPFC) to treat negative symptoms, and low-frequency rTMS to the left temporo-parietal cortex (TPC) to treat auditory hallucinations (AH) and overall positive symptoms.

RESULTS

When analyzing controlled (active arms) and uncontrolled studies together, the effect sizes showed significant and moderate effects of rTMS on negative and positive symptoms (based on PANSS-N or SANS, and PANSS-P or SAPS, respectively). However, the analysis for the sham-controlled studies revealed a small non-significant effect size for negative (0.27, p=0.417) and for positive symptoms (0.17, p=0.129). When specifically analyzing AH (based on AHRS, HCS or SAH), the effect size for the sham-controlled studies was large and significant (1.04; p=0.002).

CONCLUSIONS

These meta-analyses support the need for further controlled, larger trials to assess the clinical efficacy of rTMS on negative and positive symptoms of schizophrenia, while suggesting the need for exploration for alternative stimulation protocols.

Repetitive transcranial magnetic stimulation for negative symptoms of schizophrenia: a randomized controlled pilot study

BACKGROUND

Negative symptoms in schizophrenia are associated with deficits in executive function and frequently prove highly resistant to neuroleptic medication. Using repetitive transcranial magnetic stimulation (rTMS) to activate the prefrontal cortex has been suggested as a treatment for negative symptoms.

METHODS

We performed a double-blind randomized controlled pilot study of real versus sham rTMS for negative symptoms in schizophrenia. 17 right-handed patients with prominent negative symptoms (PANSS negative subscore >or=20) were randomized to a 10 day course of real (n=8) or sham rTMS (n=9) applied to the left dorsolateral prefrontal cortex (20 trains per day, 10 s treatment at 10 Hz, 50 s inter-train interval, 110% of motor threshold). The primary outcome measure was PANSS negative symptom score. Secondary outcomes included mood, cognitive function and side-effects. Patients were followed-up two weeks afterwards. The main effect of treatment arm was evaluated across end of treatment and two-week follow-up time points using ANCOVA.

RESULTS

All subjects completed the treatment course. There was no significant difference between the two groups on PANSS negative symptom scores at either time point. At the end of treatment, no subjects in either group met the criterion for response (i.e. a 20% reduction in baseline PANSS negative symptom score). The real rTMS group had better delayed recall on a test of verbal learning than the sham group at 2 week follow-up.

CONCLUSIONS

Real rTMS was not found to be better than sham rTMS in alleviating negative symptoms of schizophrenia although it was associated with some improvement in aspects of cognitive function at follow-up.