Repetitive transcranial magnetic stimulation (rTMS) for schizophrenia patients treated with clozapine.

OBJECTIVES: Biological strategies to improve treatment efficacy in clozapine-treated patients are urgently needed. Repetitive transcranial magnetic stimulation (rTMS) merits consideration as intervention for patients with persistent auditory hallucinations (AH) or negative symptoms (NS) not responding sufficiently to clozapine treatment. METHODS: Data from 10 international RCTs of rTMS for patients being treated with clozapine were pooled. Two levels of symptomatic response were defined: improvement of ≥20% and ≥50% on study-specific primary endpoint scales. Changes in the positive and negative syndrome scale (PANSS) from baseline to endpoint assessment were also analysed. RESULTS: Analyses of 131 patients did not reveal a significant difference for ≥20% and ≥50% response thresholds for improvement of AH, negative or total symptoms between active and sham rTMS groups. The number needed to treat (NNT) for an improvement in persistent AH was nine following active rTMS. PANSS scores did not improve significantly from baseline to endpoint between active and sham groups in studies investigating NS and AH. CONCLUSIONS: rTMS as a treatment for persistent symptoms in clozapine-treated patients did not show a beneficial effect of active compared to sham treatment. For AH, the size of the NNTs indicates a possible beneficial effect of rTMS.

Effects of bilateral prefrontal rTMS on brain activation during social-emotional evaluation in schizophrenia: A double-blind, randomized, exploratory study.

This exploratory study reports on the effects of Repetitive Transcranial Magnetic Stimulation (rTMS) on (prefrontal) brain activity changes during ambiguous emotional evaluation in patients with schizophrenia. Before and after randomly assigned treatment with active and sham rTMS, patients performed the Wall of Faces task during fMRI scanning. fMRI analysis showed that rTMS treatment resulted in reduced activation of striato-fronto-parietal brain areas, while activation increased compared to baseline after sham. Thus, prefrontal rTMS may normalize an increased brain response to ambiguous emotional stimuli, but future studies should confirm these findings.

Moderate effects of noninvasive brain stimulation of the frontal cortex for improving negative symptoms in schizophrenia: Meta-analysis of controlled trials.

BACKGROUND: Negative symptoms in schizophrenia concern a clinically relevant reduction of goal-directed behavior that strongly and negatively impacts daily functioning. Existing treatments are of marginal effect and novel approaches are needed. Noninvasive neurostimulation by means of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are novel approaches that may hold promise. OBJECTIVES: To provide a quantitative integration of the published evidence regarding effects of rTMS and tDCS over the frontal cortex on negative symptoms, including an analysis of effects of sham stimulation. METHODS: Meta-analysis was applied, using a random effects model, to calculate mean weighted effect sizes (Cohen's d). Heterogeneity was assessed by using Cochrans Q and I2 tests. RESULTS: For rTMS treatment, the mean weighted effect size compared to sham stimulation was 0.64 (0.32-0.96; k = 22, total N = 827). Studies with younger participants showed stronger effects as compared to studies with older participants. For tDCS studies a mean weighted effect size of 0.50 (-0.07 to 1.07; k = 5, total N = 134) was found. For all frontal noninvasive neurostimulation studies together (i.e., TMS and tDCS studies combined) active stimulation was superior to sham, the mean weighted effect size was 0.61 (24 studies, 27 comparisons, 95% confidence interval 0.33-0.89; total N = 961). Sham rTMS (baseline - posttreatment comparison) showed a significant improvement of negative symptoms, d = 0.31 (0.09-0.52; k = 16, total N = 333). Whereas previous meta-analyses were underpowered, our meta-analysis had a power of 0.87 to detect a small effect. CONCLUSIONS: The available evidence indicates that noninvasive prefrontal neurostimulation can improve negative symptoms. This finding suggests a causal role for the lateral frontal cortex in self-initiated goal-directed behavior. The evidence is stronger for rTMS than for tDCS, although this may be due to the small number of studies as yet with tDCS. More research is needed to establish moderator variables that may affect response to neurostimulation and to optimize treatment parameters in order to achieve stable and durable (and thus clinically relevant) effects.

Effect of Bilateral Prefrontal rTMS on Left Prefrontal NAA and Glx Levels in Schizophrenia Patients with Predominant Negative Symptoms: An Exploratory Study.

BACKGROUND: Prefrontal repetitive Transcranial Magnetic Stimulation (rTMS) may improve negative symptoms in patients with schizophrenia, but few studies have investigated the underlying neural mechanism. OBJECTIVE: This study aims to investigate changes in the levels of glutamate and glutamine (Glx, neurotransmitter and precursor) and N-Acetyl Aspartate (NAA) in the left dorsolateral prefrontal cortex of patients with schizophrenia treated with active bilateral prefrontal rTMS as compared to sham-rTMS, as measured with 1H-Magnetic Resonance Spectroscopy (1H-MRS). METHODS: Patients were randomized to a 3-week course of active or sham high-frequency rTMS. Pre-treatment and post-treatment 1H-MRS data were available for 24 patients with schizophrenia with moderate to severe negative symptoms (Positive and Negative Syndrome Scale (PANSS) negative subscale ≥ 15). Absolute metabolite concentrations were calculated using LCModel with the water peak as reference. To explore the association between treatment condition and changes in concentration of Glx and NAA, we applied a linear regression model. RESULTS: We observed an increase of Glx concentration in the active treatment group and a decrease of Glx concentration in the group receiving sham treatment. The association between changes in Glx concentration and treatment condition was significant. No significant associations between changes in NAA and treatment condition were found. CONCLUSIONS: Noninvasive neurostimulation with high-frequency bilateral prefrontal rTMS may influence Glx concentration in the prefrontal cortex of patients with schizophrenia. Larger studies are needed to confirm these findings and further elucidate the underlying neural working mechanism of rTMS.

Effect of rTMS on brain activation in schizophrenia with negative symptoms: A proof-of-principle study.

BACKGROUND: Prefrontal cortical dysfunction is frequently reported in schizophrenia and is thought to underlie negative symptoms of schizophrenia. Repetitive Transcranial Magnetic Stimulation (rTMS) can modulate neuronal activity and has been shown to improve negative symptoms in patients with schizophrenia, but the underlying neural mechanism is unknown. OBJECTIVE: To examine whether 3weeks of 10Hz rTMS treatment of the bilateral dorsolateral prefrontal cortex (DLPFC) would improve frontal brain activation in patients with negative symptoms of schizophrenia, as measured by functional magnetic resonance imaging (fMRI) during the Tower of London (ToL) task. METHODS: 24 patients with the diagnosis of schizophrenia with moderate to severe negative symptoms (Positive and Negative Syndrome Scale (PANSS) negative subscale≥15) participated. Patients were randomized to a 3-week (15day) course of active or sham rTMS. All patients performed the ToL task during fMRI scanning both pre-treatment and post-treatment. Differences in brain activation between the two groups were compared non-parametrically. RESULTS: After rTMS treatment, brain activity in the active group increased in the right DLPFC and the right medial frontal gyrus as compared to the sham group. In addition, the groups significantly differed with regard to activation change in the left posterior cingulate, with decreased activation in the active and increased activation in the sham group. CONCLUSIONS: Treatment with rTMS over the DLPFC may have the potential for increasing task-related activation in frontal areas in patients with schizophrenia. Effects of different rTMS parameters and fMRI tasks targeting relevant brain circuitry deserve further investigation. TRIAL REGISTRATION: Nederlands Trial Register, registration number: NTR1261.

Neural correlates of planning performance in patients with schizophrenia--relationship with apathy.

Patients with schizophrenia often suffer from apathy: a quantitative reduction of voluntary, goal-directed behaviors that impairs daily functioning. We hypothesized that schizophrenia patients with high levels of apathy would show decreased activation in brain regions involved in planning and goal-directed behavior. Patients with schizophrenia or psychotic spectrum disorder (n=47) and healthy controls (n=20) performed the Tower of London (ToL) task during fMRI scanning using arterial spin labeling. To investigate the relationship between apathy and planning in patients, a proxy measure of apathy based on the Positive and Negative syndrome Scale was regressed against the task-related brain activation. Brain activation was also compared between patients and healthy controls. Higher levels of apathy were associated with less task-related activation within the inferior parietal lobule precuneus and thalamus. Compared to controls, patients showed lower activation in lateral prefrontal regions, parietal and motor areas, and a higher activation of medial frontal areas. Apathy was related to abnormal activation in thalamus and parietal regions during the ToL task. This supports the hypothesis that impaired function of brain regions involved in planning and goal-directed behavior may underlie apathy in schizophrenia. Moreover, impaired lateral prefrontal activation in schizophrenia patients compared to controls is consistent with the hypofrontality model of schizophrenia. In contrast, stronger medial frontal activation in patients may be related to increased effort to perform a task with conflicting task solutions.

Repetitive transcranial magnetic stimulation for negative symptoms of schizophrenia: review and meta-analysis.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a treatment for the negative symptoms of schizophrenia. During the past decade, several trials have reported on the efficacy of rTMS treatment; however, the results were inconsistent. OBJECTIVE: To assess the efficacy of prefrontal rTMS for treating negative symptoms of schizophrenia. DATA SOURCES: A literature search was performed in PubMed, ISI Web of Science, and EMBASE for the years 1985 through July 2008. The search terms used (language not specified) were "transcranial magnetic stimulation," "negative symptoms," and "schizophrenia." A cross-reference search of eligible articles was performed to identify studies not found in the computerized search. STUDY SELECTION: Studies selected were randomized controlled trials assessing the therapeutic efficacy of prefrontal rTMS for negative symptoms in schizophrenia. DATA EXTRACTION: Effect sizes (Cohen d) of each study were calculated. The overall standardized mean difference was calculated under a random effects model with 95% confidence intervals. DATA SYNTHESIS: Nine trials, involving 213 patients, were included in the meta-analysis. The overall mean weighted effect size for rTMS versus sham was in the small-to-medium range and statistically significant (d = 0.43; 95% CI, 0.05-0.80). When including only the studies using a frequency of stimulation of 10 Hz, the mean effect size increased to 0.63 (95% CI, 0.11-1.15). When including only the studies requiring participants to be on a stable drug regimen before and during the study, the mean weighted effect size decreased to 0.34 (95% CI, 0.01-0.67). Studies with a longer duration of treatment (> or =3 weeks) had a larger mean effect size when compared to studies with a shorter treatment duration: d = 0.58 (95% CI, 0.19-0.97) and d = 0.32 (95% CI, -0.3 to 0.95), respectively. CONCLUSIONS: The results of this meta-analysis warrant further study of rTMS as a potential treatment of negative symptoms of schizophrenia.