Priming does not enhance the efficacy of 1 Hertz repetitive transcranial magnetic stimulation for the treatment of auditory verbal hallucinations: Results of a randomized controlled study

Safety of rTMS for Schizophrenia: A Systematic Review and Meta-analysis

BACKGROUND AND HYPOTHESIS

Current treatments for schizophrenia are only partially effective, and there are no medications for negative symptoms or cognitive impairment. Neuromodulation, such as repetitive transcranial magnetic stimulation (rTMS), has potential as a novel intervention for schizophrenia. Prior to clinical use, rTMS should have demonstrated safety in a large schizophrenia population. However, the safety profile of rTMS in schizophrenia is not well characterized, and regulatory agencies have expressed concern about safety in this population.

STUDY DESIGN

We conducted a systematic review with meta-analysis of rTMS studies in schizophrenia. We searched PubMed, the Cochrane Library, PsycINFO, and Science Citation Index Expanded for rTMS studies in schizophrenia that reported adverse effects. We extracted the number of participants who experienced an adverse effect and calculated the prevalence of each adverse effect for active or sham rTMS. We tested the difference between the prevalence of events in the active and sham conditions. We assessed risk of bias using the Cochrane Handbook.

STUDY RESULTS

The initial search identified 1472 studies. After screening, 261 full-text studies were assessed, and 126 met inclusion criteria (N = 4122 total subjects). The prevalence of headache or scalp pain, dizziness or syncope, facial twitching, and nausea was higher for active rTMS compared to sham (P < .05). The prevalence of all other adverse effects, including seizure, was not different between active and sham rTMS.

CONCLUSIONS

rTMS is safe and well tolerated for people with schizophrenia. Individuals with schizophrenia are not at increased risk for adverse effects, including seizure, compared to the general population.

Rich-club reorganization of white matter structural network in schizophrenia patients with auditory verbal hallucinations following 1 Hz rTMS treatment

The human brain comprises a large-scale structural network of regions and interregional pathways, including a selectively defined set of highly central and interconnected hub regions, often referred to as the "rich club", which may play a pivotal role in the integrative processes of the brain. A quintessential symptom of schizophrenia, auditory verbal hallucinations (AVH) have shown a decrease in severity following low-frequency repetitive transcranial magnetic stimulation (rTMS). However, the underlying mechanism of rTMS in treating AVH remains elusive. This study investigated the effect of low-frequency rTMS on the rich-club organization within the brain in patients diagnosed with schizophrenia who experience AVH using diffusion tensor imaging data. Through by constructing structural connectivity networks, we identified several critical rich hub nodes, which constituted a rich-club subnetwork, predominantly located in the prefrontal cortices. Notably, our findings revealed enhanced connection strength and density within the rich-club subnetwork following rTMS treatment. Furthermore, we found that the decreased connectivity within the subnetwork components, including the rich-club subnetwork, was notably enhanced in patients following rTMS treatment. In particular, the increased connectivity strength of the right median superior frontal gyrus, which functions as a critical local bridge, with the right postcentral gyrus exhibited a significant correlation with improvements in both positive symptoms and AVH. These findings provide valuable insights into the role of rTMS in inducing reorganizational changes within the rich-club structural network in schizophrenia and shed light on potential mechanisms through which rTMS may alleviate AVH.

Assessment of treatment resistance criteria in non-invasive brain stimulation studies of schizophrenia

Novel treatment modalities, such as non-invasive brain stimulation (NIBS), typically focus on patient groups that have failed multiple treatment interventions. Despite its promise, the clinical translation of NIBS in schizophrenia has been limited. One important obstacle to implementation is the inconsistent reporting of treatment resistance in the clinical trial literature contributing to heterogeneity in reported effects. In response, we develop a numerical approach to synthesize quality of assessment of Treatment-Resistant Schizophrenia (TRS) and apply this to studies investigating therapeutic response to NIBS in patients with schizophrenia. Literature search conducted through PubMed database identified 119 studies investigating Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation in treating resistant schizophrenia symptoms. A quality score out of 11 was assigned to each study based on adherence to the international consensus guidelines for TRS developed by the Treatment Response and Resistance in Psychosis (TRRIP) group. Results revealed an overall paucity of studies with thorough assessment and/or reporting of TRS phenomenon, as evidenced by a mean quality score of 3.38/11 (SD: 1.01) for trials and 5.16/11 (SD: 1.57) for case reports, though this improved minimally since the publication of consensus criteria. Most studies considered treatment-resistance as a single dimensional construct by reporting resistance of a single symptom, and failed to establish treatment adherence, resistance time course and functional impairment. We conclude that the current NIBS literature in schizophrenia do not reflect its true effects on treatment-resistance. There is an urgent need to improve assessment and reporting standards of clinical trials that target TRS.

Adjuvant Priming Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Obsessive-Compulsive Disorder: In Search of a New Paradigm!

OBJECTIVES

Repetitive transcranial magnetic stimulation (rTMS) is used as a therapeutic option for obsessive-compulsive disorder (OCD) in both clinical and research settings. There has been no consensus with regard to target area and other parameters, although 1-Hz rTMS over the supplementary motor area (SMA) is found to be promising. Priming stimulation, which involves high-frequency followed by low-frequency rTMS, has been shown to enhance neural response to low-frequency rTMS. Hence, this study was conducted to investigate the effect of adjunctive priming rTMS over the SMA in treatment-resistant OCD.

METHODS

Thirty patients with OCD who were symptomatic after an adequate selective serotonin reuptake inhibitor trial were randomized into 2 groups: one group receiving active priming stimulation (6-Hz rTMS at 80% resting motor threshold) followed by 1-Hz rTMS (priming rTMS group) and the other receiving sham stimulation followed by 1-Hz rTMS (rTMS-only group). Both groups received 10 sessions of such interventions for 2 weeks. Both the rater and patients were blind to the treatment allocation. Assessments were done using the Yale-Brown Obsessive Compulsive Scale, Hamilton Rating Scale for Depression, Hamilton Rating Scale for Anxiety, and Clinical Global Impression-Improvement scale at baseline, 2 weeks, and 4 weeks.

RESULTS

Both groups showed a significant improvement in all domains of psychopathology over time. The priming rTMS group was better than the rTMS-only group in reducing the Yale-Brown Obsessive Compulsive Scale compulsion score (P < 0.023) as well as scores of the Hamilton Rating Scale for Anxiety, Hamilton Rating Scale for Depression, and Clinical Global Impression-Improvement scale. None developed any adverse effects requiring medical attention.

CONCLUSIONS

Priming rTMS over the SMA is safe and has favorable effects in OCD. It seems to have a predominant effect on the reduction of compulsions, presumably rectifying the impaired response inhibition in patients with OCD.

The alternations of nucleus accumbent in schizophrenia patients with auditory verbal hallucinations during low-frequency rTMS treatment

Low-frequency repetitive transcranial magnetic stimulation (rTMS) has been shown to reduce the severity of auditory verbal hallucinations (AVH) and induce beneficial functional and structural alternations of the brain in schizophrenia patients with AVH. The nucleus accumbens (NAcc) as an important component of the ventral striatum is implicated with the pathology in AVH. However, the induced characteristic patterns of NAcc by low-frequency rTMS in schizophrenia with AVH are seldom explored. We investigated the functional and structural characteristic patterns of NAcc by using seed-based functional connectivity (FC) analysis and gray matter volume (GMV) measurement in schizophrenia patients with AVH during 1 Hz rTMS treatment. Although low-frequency rTMS treatment did not affect the volumetric changes of NAcc, the abnormal FC patterns of NAcc, including increased FC of NAcc with the temporal lobes and decreased FC of NAcc with the frontal cortices in the pretreatment patients compared to healthy controls, were normalized or reversed after treatment. These FC changes were associated with improvements in clinical symptoms and neurocognitive functions. Our findings may extend our understanding of the NAcc in the pathology of schizophrenia with AVH and might be a biomarker of clinical effect for low-frequency rTMS treatment in schizophrenia.

Repetitive transcranial magnetic stimulation and transcranial direct current stimulation for auditory hallucinations in schizophrenia: Systematic review and meta-analysis

Through imaging studies, a significant increase in cerebral activity has been detected in fronto-temporal areas in patients experiencing auditory verbal hallucinations. Therefore, non-invasive neuromodulation, in particular transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), has been considered as a therapeutic intervention for medication-resistant auditory verbal hallucinations in schizophrenia. We aimed to synthesize results from randomized trials on either rTMS or tDCS versus placebo in patients with schizophrenia by including five recently published trials in the field. A systematic review and meta-analysis of relevant literature was conducted. Studies were included on the basis of pre-defined selection criteria. The quality of the studies was assessed by the Cochrane Risk of Bias Tool for Randomized Controlled Trials. RevMan 5.3 was used to conduct the statistical analysis. Including 465 and 960 patients, respectively, 12 tDCS and 27 rTMS studies were included. Regarding treatment of medication refractory auditory verbal hallucinations, no significant effect of tDCS (-0.23 [-0.49, 0.02], p = 0.08) or rTMS (-0.19 [-0.50, 0,11], p = 0.21) was found compared to sham in this meta-analysis. The current study found that it cannot be concluded that rTMS and tDCS are efficacious in treating medication-resistant auditory verbal hallucinations. Larger randomized controlled tDCS trials of a higher quality should be conducted in the future to establish substantial evidence of tDCS. The interventions appear safe and may have beneficial effects on other outcomes.

Transcranial magnetic stimulation (TMS) for schizophrenia

BACKGROUND

People with schizophrenia often experience symptoms which fail to fully respond to antipsychotic medication. Transcranial magnetic stimulation (TMS) has been proposed as a new treatment for people with schizophrenia, especially those who experience persistent auditory hallucinations.

OBJECTIVES

To estimate the effects of TMS alone, compared with sham TMS or with 'standard management' and any other comparison interventions in reducing psychotic symptoms associated with schizophrenia.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group Trials Register (June 2006, June 2008, April 2013). This register is compiled by methodical searches of MEDLINE, EMBASE, BIOSIS, CINAHL, Dissertation abstracts, LILACS, PSYNDEX, PsycINFO, RUSSMED, and Sociofile, and is supplemented with handsearching of relevant journals and numerous conference proceedings.

SELECTION CRITERIA

We included all randomised controlled trials recruiting at least five participants and comparing TMS with sham TMS or any other treatment for people with schizophrenia.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data we calculated relative risks (RRs) and their 95% confidence intervals (CIs). For continuous data, we calculated mean differences (MD) and 95% CI. We used a fixed-effect model. We assessed overall quality of the evidence using the GRADE approach.

MAIN RESULTS

We included 41 studies with 1473 participants in the review. We found significant differences in favour of temporoparietal TMS compared to sham TMS for global state measured on the CGI scale (7 RCTs, n = 224, MD -0.5, 95% CI -0.76 to -0.23, very low-quality evidence) and positive symptoms measured on the PANSS scale (5 RCTs, n = 127, MD -6.09, 95% CI -10.95 to -1.22, very low-quality evidence). Participants experienced significantly more headaches in the temporoparietal TMS group (10 RCTs, n = 392, RR 2.65, 95% CI 1.56 to 4.50, very low-quality evidence). However, no more participants left the study early from the TMS group than from the sham group (very low-quality evidence). Cognitive state was assessed using 39 different measures, and all were equivocal (very low-quality evidence).We included only two trials which compared temporoparietal TMS with standard treatment. In both trials the participants received first- and second-generation antipsychotic medication in both treatment groups, therefore TMS was used an adjunctive therapy to medication. We found no significant differences in the number of participants that showed clinical improvement in global state (1 RCT, n = 100, RR 1.19, 95% CI 0.91 to 1.57) or left the study early (2 RCTs, n = 140, RR 0.33, 95% CI 0.08 to 1.46) (both very low-quality evidence). No studies reported on global state score, mental state, cognitive state and adverse effects.For prefrontal TMS compared to sham TMS, global state was measured on three different scales, all of which presented equivocal results (very low quality evidence). We could not pool data for mental state on the PANSS scale due to high heterogeneity. Cognitive state was assessed using 19 different measures, with 15/19 being equivocal (very low-quality evidence). Prefrontal TMS caused more headaches (6 RCTs, n = 164, RR 2.77, 95% CI 1.22 to 6.26, very low-quality evidence) but there was no difference in the number of participants leaving the study early (very low-quality evidence). No studies reported data for clinical improvement.We found a significant difference in favour of prefrontal theta burst stimulation TMS compared to sham TMS for mental state on the PANNS scale (3 RCTs, n = 108, MD -5.71, 95% CI -9.32 to -2.10, very low evidence). We found no difference for clinical improvement, cognitive state, number of headaches, and leaving the study early (very low-quality evidence).None of the included studies reported satisfaction with care.

AUTHORS' CONCLUSIONS

Based on this review, there is insufficient evidence to support or refute the use of TMS to treat symptoms of schizophrenia. Although some evidence suggests that TMS, and in particular temporoparietal TMS, may improve certain symptoms (such as auditory hallucinations and positive symptoms of schizophrenia) compared to sham TMS, the results were not robust enough to be unequivocal across the assessment measures used. There was insufficient evidence to suggest any added benefit with TMS used as an adjunctive therapy to antipsychotic medication.The overall quality of evidence was graded as very low due to risk of bias, and this was accompanied by an imprecision in estimates due to the relatively small number of participants in the studies. Thus, consideration is required in improving the quality of trial processes, as well as the quality of reporting of ongoing and future TMS trials, so as to facilitate accurate future judgements in assessing risk of bias. Differences in TMS techniques in relation to stimulation intensity, stimulation length, brain areas stimulated and variations in the design of sham TMS all contributed to the heterogeneity of study findings and limited the interpretation and applicability of the results. In addition, the trials assessed their outcomes with a variety of scales, and usable data were limited. Therefore, to better evaluate the treatment effects of TMS in people with schizophrenia, we favour the use of standardised treatment protocols and outcome measures.

Adjuvant low-frequency rTMS in treating auditory hallucinations in recent-onset schizophrenia: a randomized controlled study investigating the effect of high-frequency priming stimulation

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has been found to be effective in reducing frequency and duration of auditory verbal hallucinations (AVH). Priming stimulation, which involves high-frequency rTMS stimulation followed by low-frequency rTMS, has been shown to markedly enhance the neural response to the low-frequency stimulation train. However, this technique has not been investigated in recent onset schizophrenia patients. The aim of this randomized controlled study was to investigate whether the effects of rTMS on AVH can be enhanced with priming rTMS in recent onset schizophrenia patients.

METHODS

Forty recent onset schizophrenia patients completed the study. Patients were randomized over two groups: one receiving low-frequency rTMS preceded by priming and another receiving low-frequency rTMS without priming. Both treatments were directed at the left temporo-parietal region. The severity of AVH and other psychotic symptoms were assessed with the auditory hallucination subscale (AHRS) of the Psychotic Symptom Rating Scales (PSYRATS), the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression (CGI).

RESULTS

We found that all the scores of these ratings significantly reduced over time (i.e. baseline through 1, 2, 4 and 6 weeks) in both the treatment groups. We found no difference between the two groups on all measures, except for significantly greater improvement on loudness of AVH in the group with priming stimulation during the follow-ups (F = 2.72; p < .05).

CONCLUSIONS

We conclude that low-frequency rTMS alone and high-frequency priming of low-frequency rTMS do not elicit significant differences in treatment of overall psychopathology, particularly AVH when given in recent onset schizophrenia patients. Add on priming however, seems to be particularly better in faster reduction in loudness of AVH.

Review of the efficacy of transcranial magnetic stimulation for auditory verbal hallucinations

With an increase of the number of studies exploring repetitive transcranial magnetic stimulation (rTMS) for the treatment of auditory verbal hallucinations (AVH), an update is provided on the efficacy of different paradigms. A literature search was performed from 1966 through April 2013. Twenty-five randomized controlled trials using the severity of AVH or psychosis as outcome measures were included. Standardized mean weighted effect sizes were computed; a qualitative review of the literature was performed to assess the effects of various rTMS paradigms. rTMS versus sham treatment for AVH yielded a mean weighted effect size of .44. No significant mean weighted effect size was found for the severity of psychosis (i.e., .21). For patients with medication-resistant AVH, the mean weighted effect size was .45. rTMS applied at the left temporoparietal area with a frequency of 1 Hz yielded a moderate mean weighted effect size of .63, indicating superiority of this paradigm. Various other paradigms failed to show superior effects. rTMS applied at the right temporoparietal area was not superior to sham treatment. rTMS, especially when applied at the left temporoparietal area with a frequency of 1 Hz, is effective for the treatment of AVH, including in patients with medication-resistant AVH. The results for other rTMS paradigms are disappointing thus far. A next step should be to explore the effects of rTMS in medication-free individuals, for example, during the initial phases of psychosis, and in patients with diagnoses other than schizophrenia who do not have comorbid psychotic symptoms.

Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS)

A group of European experts was commissioned to establish guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS) from evidence published up until March 2014, regarding pain, movement disorders, stroke, amyotrophic lateral sclerosis, multiple sclerosis, epilepsy, consciousness disorders, tinnitus, depression, anxiety disorders, obsessive-compulsive disorder, schizophrenia, craving/addiction, and conversion. Despite unavoidable inhomogeneities, there is a sufficient body of evidence to accept with level A (definite efficacy) the analgesic effect of high-frequency (HF) rTMS of the primary motor cortex (M1) contralateral to the pain and the antidepressant effect of HF-rTMS of the left dorsolateral prefrontal cortex (DLPFC). A Level B recommendation (probable efficacy) is proposed for the antidepressant effect of low-frequency (LF) rTMS of the right DLPFC, HF-rTMS of the left DLPFC for the negative symptoms of schizophrenia, and LF-rTMS of contralesional M1 in chronic motor stroke. The effects of rTMS in a number of indications reach level C (possible efficacy), including LF-rTMS of the left temporoparietal cortex in tinnitus and auditory hallucinations. It remains to determine how to optimize rTMS protocols and techniques to give them relevance in routine clinical practice. In addition, professionals carrying out rTMS protocols should undergo rigorous training to ensure the quality of the technical realization, guarantee the proper care of patients, and maximize the chances of success. Under these conditions, the therapeutic use of rTMS should be able to develop in the coming years.