Clinical impacts of single transcranial magnetic stimulation (sTMS) as an add-on therapy in severely depressed patients under SSRI treatment

A Review of Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation Combined with Medication and Psychotherapy for Depression

LEARNING OBJECTIVES

After participating in this CME activity, the psychiatrist should be better able to:• Compare and contrast therapies used in combination with transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) for treating MDD.

BACKGROUND

Noninvasive neuromodulation, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), has emerged as a major area for treating major depressive disorder (MDD). This review has two primary aims: (1) to review the current literature on combining TMS and tDCS with other therapies, such as psychotherapy and psychopharmacological interventions, and (2) to discuss the efficacy, feasibility, limitations, and future directions of these combined treatments for MDD.

METHOD

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched three databases: PubMed, PsycInfo, and Cochrane Library. The last search date was December 5, 2023.

RESULTS

The initial search revealed 2,519 records. After screening and full-text review, 58 studies (7 TMS plus psychotherapy, 32 TMS plus medication, 7 tDCS plus psychotherapy, 12 tDCS plus medication) were included.

CONCLUSIONS

The current literature on tDCS and TMS paired with psychotherapy provides initial support for integrating mindfulness interventions with both TMS and tDCS. Adding TMS or tDCS to stable doses of ongoing medications can decrease MDD symptoms; however, benzodiazepines may interfere with TMS and tDCS response, and antipsychotics can interfere with TMS response. Pairing citalopram with TMS and sertraline with tDCS can lead to greater MDD symptom reduction compared to using these medications alone. Future studies need to enroll larger samples, include randomized controlled study designs, create more uniform protocols for combined treatment delivery, and explore mechanisms and predictors of change.

Brainwaves Oscillations as a Potential Biomarker for Major Depression Disorder Risk

Major depressive disorder (MDD) is a multidimensional disorder that is characterized by the presence of alterations in mood, cognitive capacity, sensorimotor, and homeostatic functions. Given that about half of the patients diagnosed with MDD do not respond to the various current treatments, new techniques are being sought to predict not only the course of the disease but also the characteristics that differentiate responders from non-responders. Using the electroencephalogram, a noninvasive and inexpensive tool, most studies have proposed that patients with MDD have some lateralization in brain electrical activity, with alterations in alpha and theta rhythms being observed, which would be related to dysfunctions in emotional capacity such as the absence or presence of responses to the different existing treatments. These alterations help in the identification of subjects at high risk of suffering from depression, in the differentiation into responders and nonresponders to various therapies (pharmacological, electroconvulsive therapy, and so on), as well as to establish in which period of the disease the treatment will be more effective. Although the data are still inconclusive and more research is needed, these alpha and theta neurophysiological markers could support future clinical practice when it comes to establishing an early diagnosis and treating state disorders more successfully and accurately of mood disorders.

A systematic literature review of the clinical efficacy of repetitive transcranial magnetic stimulation (rTMS) in non-treatment resistant patients with major depressive disorder

BACKGROUND

The clinical efficacy of repetitive transcranial magnetic stimulation (rTMS) in treatment resistant patients (at least 4 medication trials) appears to be well accepted and forms the coverage policies and rTMS's use in many of the largest US payers. However, less is known about rTMS's use in patients who have undergone ≤1 failed medication trial. The purpose of this analysis was to determine the clinical efficacy of rTMS in patients after ≤1 medication trials.

METHODS

A systematic review of the literature was undertaken to identify all articles which addressed the use of rTMS in ≤1 medication trial. All types of study designs were included and assessed for quality and strength of evidence using: GRADE and CEBM. Searches of peer reviewed articles were undertaken for the year 2000 to the present. All languages were considered. Electronic databases were searched and included: PubMed and EBSCO. Evidence assessment websites were also searched and included: Cochrane, NICE, AHRQ, and ICER. Additionally, the clinical guidelines for specialty societies which use rTMS was searched. Hand searches of the reference sections of identified articles was also undertaken.

RESULTS

Electronic and other sources identified 165 after duplicates were removed. Twenty two articles were assessed for eligibility and ultimately 10 articles were included in the systematic review and graded. Six articles were graded high quality (CEBM/GRADE: 1c/B) demonstrating that the use of rTMS was clinically efficacious in patients after ≤1 medication trial. Four additional trials demonstrated a positive effect of rTMS in patients after ≤1 medication trial but were of a lower quality.

CONCLUSION

The use of rTMS in patients after ≤1 medication trial should be considered. US payers should consider revising their coverage policies to include the use of rTMS in these patients.

Differentiating responders and non-responders to rTMS treatment for depression after one week using resting EEG connectivity measures

BACKGROUND

Non-response to repetitive transcranial magnetic stimulation (rTMS) treatment for depression is costly for both patients and clinics. Simple and cheap methods to predict response would reduce this burden. Resting EEG measures differentiate responders from non-responders, so may have utility for response prediction.

METHODS

Fifty patients with treatment resistant depression and 21 controls had resting electroencephalography (EEG) recorded at baseline (BL). Patients underwent 5-8 weeks of rTMS treatment, with EEG recordings repeated at week 1 (W1). Forty-two participants had valid BL and W1 EEG data, and 12 were responders. Responders and non-responders were compared at BL and W1 in measures of theta (4-8 Hz) and alpha (8-13 Hz) power and connectivity, frontal theta cordance and alpha peak frequency. Control group comparisons were made for measures that differed between responders and non-responders. A machine learning algorithm assessed the potential to differentiate responders from non-responders using EEG measures in combination with change in depression scores from BL to W1.

RESULTS

Responders showed elevated theta connectivity across BL and W1. No other EEG measures differed between groups. Responders could be distinguished from non-responders with a mean sensitivity of 0.84 (p = 0.001) and specificity of 0.89 (p = 0.002) using cross-validated machine learning classification on the combination of all EEG and mood measures.

LIMITATIONS

The low response rate limited our sample size to only 12 responders.

CONCLUSION

Resting theta connectivity at BL and W1 differ between responders and non-responders, and show potential for predicting response to rTMS treatment for depression.

QEEG Theta Cordance in the Prediction of Treatment Outcome to Prefrontal Repetitive Transcranial Magnetic Stimulation or Venlafaxine ER in Patients With Major Depressive Disorder

The aims of this double-blind study were to assess and compare the efficacy of quantitative electroencephalographic (QEEG) prefrontal theta band cordance in the prediction of response to 4-week, right, prefrontal, 1-Hz repetitive transcranial magnetic stimulation (rTMS) or venlafaxine ER in patients with major depressive disorder (MDD). Prefrontal QEEG cordance values of 50 inpatients (25 subjects in each group) completing 4 weeks of the study were obtained at baseline and after 1 week of treatment. Depressive symptoms were assessed using Montgomery-Åsberg Depression Rating Scale (MADRS) at baseline and at week 1 and 4. Treatment response was defined as a ≥50% reduction in baseline MADRS total score. All responders (n = 9) and 6 of 16 nonresponders in the rTMS group had reduced cordance at week 1 (P < .01). Reduction of theta cordance value at week 1 was detected in all responders (n = 10) to venlafaxine ER, but only in 4 of 15 nonresponders (P = .005). The comparison of the areas under the curve of cordance change for prediction of response between rTMS (0.75) and venlafaxine ER (0.89) treated groups yielded no significant difference (P = .27). Our study indicates that prefrontal QEEG cordance is a promising tool not only for predicting the response to certain antidepressants but also to rTMS treatment, with comparable predictive efficacy for both therapeutic interventions.

EEG biomarkers in major depressive disorder: discriminative power and prediction of treatment response

Major depressive disorder (MDD) has high population prevalence and is associated with substantial impact on quality of life, not least due to an unsatisfactory time span of sometimes several weeks from initiation of treatment to clinical response. Therefore extensive research focused on the identification of cost-effective and widely available electroencephalogram (EEG)-based biomarkers that not only allow distinguishing between patients and healthy controls but also have predictive value for treatment response for a variety of treatments. In this comprehensive overview on EEG research on MDD, biomarkers that are either assessed at baseline or during the early course of treatment and are helpful in discriminating patients from healthy controls and assist in predicting treatment outcome are reviewed, covering recent decades up to now. Reviewed markers include quantitative EEG (QEEG) measures, connectivity measures, EEG vigilance-based measures, sleep-EEG-related measures and event-related potentials (ERPs). Further, the value and limitations of these different markers are discussed. Finally, the need for integrated models of brain function and the necessity for standardized procedures in EEG biomarker research are highlighted to enhance future research in this field.

Mechanisms of human motor cortex facilitation induced by subthreshold 5-Hz repetitive transcranial magnetic stimulation

Our knowledge about the mechanisms of human motor cortex facilitation induced by repetitive transcranial magnetic stimulation (rTMS) is still incomplete. Here we used pharmacological conditioning with carbamazepine, dextrometorphan, lorazepam, and placebo to elucidate the type of plasticity underlying this facilitation, and to probe if mechanisms reminiscent of long-term potentiation are involved. Over the primary motor cortex of 10 healthy subjects, we applied biphasic rTMS pulses of effective posterior current direction in the brain. We used six blocks of 200 pulses at 5-Hz frequency and 90% active motor threshold intensity and controlled for corticospinal excitability changes using motor-evoked potential (MEP) amplitudes and latencies elicited by suprathreshold pulses before, in between, and after rTMS. Target muscle was the dominant abductor digiti minimi muscle; we coregistered the dominant extensor carpi radialis muscle. We found a lasting facilitation induced by this type of rTMS. The GABAergic medication lorazepam and to a lesser extent the ion channel blocker carbamazepine reduced the MEP facilitation after biphasic effective posteriorly oriented rTMS, whereas the N-methyl-d-aspartate receptor-antagonist dextrometorphan had no effect. Our main conclusion is that the mechanism of the facilitation induced by biphasic effective posterior rTMS is more likely posttetanic potentiation than long-term potentiation. Additional findings were prolonged MEP latency under carbamazepine, consistent with sodium channel blockade, and larger MEP amplitudes from extensor carpi radialis under lorazepam, suggesting GABAergic involvement in the center-surround balance of excitability.

The effects of QEEG-informed neurofeedback in ADHD: an open-label pilot study

In ADHD several EEG biomarkers have been described before, with relevance to treatment outcome to stimulant medication. This pilot-study aimed at personalizing neurofeedback treatment to these specific sub-groups to investigate if such an approach leads to improved clinical outcomes. Furthermore, pre- and post-treatment EEG and ERP changes were investigated in a sub-group to study the neurophysiological effects of neurofeedback. Twenty-one patients with ADHD were treated with QEEG-informed neurofeedback and post-treatment effects on inattention (ATT), hyperactivity/impulsivity (HI) and comorbid depressive symptoms were investigated. There was a significant improvement for both ATT, HI and comorbid depressive complaints after QEEG-informed neurofeedback. The effect size for ATT was 1.78 and for HI was 1.22. Furthermore, anterior individual alpha peak frequency (iAPF) demonstrated a strong relation to improvement on comorbid depressive complaints. Pre- and post-treatment effects for the SMR neurofeedback sub-group exhibited increased N200 and P300 amplitudes and decreased SMR EEG power post-treatment. This pilot study is the first study demonstrating that it is possible to select neurofeedback protocols based on individual EEG biomarkers and suggests this results in improved treatment outcome specifically for ATT, however these results should be replicated in further controlled studies. A slow anterior iAPF at baseline predicts poor treatment response on comorbid depressive complaints in line with studies in depression. The effects of SMR neurofeedback resulted in specific ERP and EEG changes.

Why do some promising brain-stimulation devices fail the next steps of clinical development?

Interest in techniques of noninvasive brain stimulation (NIBS) has been growing exponentially in the last decade. Recent studies have shown that some of these techniques induce significant neurophysiological and clinical effects. Although recent results are promising, there are several techniques that have been abandoned despite positive initial results. In this study, we performed a systematic review to identify NIBS methods with promising preliminary clinical results that were not fully developed and adopted into clinical practice, and discuss its clinical, research and device characteristics. We identified five devices (transmeatal cochlear laser stimulation, transcranial micropolarization, transcranial electrostimulation, cranial electric stimulation and stimulation with weak electromagnetic fields) and compared them with two established NIBS devices (transcranial magnetic stimulation and transcranial direct current stimulation) and with well-known drugs used in neuropsychiatry (pramipexole and escitalopram) in order to understand the reasons why they failed to reach clinical practice and further steps of research development. Finally, we also discuss novel NIBS devices that have recently showed promising results: brain ultrasound and transcranial high-frequency random noise stimulation. Our results show that some of the reasons for the failure of NIBS devices with promising clinical findings are the difficulty to disseminate results, lack of controlled studies, duration of research development, mixed results and lack of standardization.

Predicting positive and negative treatment responses to stimulants with brain SPECT imaging

The goal of this study was to test whether clinician-rated regional cerebral blood flow (rCBF) as rendered by SPECT imaging is a meaningful predictor of patient response to CNS stimulants. Chart reviews were used to identify patients who reported prior significant positive and negative responses to CNS stimulants. Each patient in the study had received resting and concentration SPECT scans using Tc99m exametazime. Differences in cerebral blood flow for frontal regions of interest were assessed in three conditions (resting, concentration, and their difference, or "delta") using ANCOVAs and age-matched ANOVAs. Prefrontal pole deltas were found to be highly sensitive and specific predictors of response to CNS stimulants, with pole activation predicting adverse responses and pole deactivation predicting good responses. Positive and negative predictive values were greater than .75 for both poles. We conclude that SPECT renderings of rCBF, particularly in the prefrontal cortex, are a potentially powerful clinical tool for anticipating response to stimulant medications, both positive and adverse.

Acute prefrontal cortex transcranial magnetic stimulation in healthy volunteers: no effects on brain-derived neurotrophic factor (BDNF) concentrations in serum

BACKGROUND

Transcranial magnetic stimulation (TMS) of the dorsolateral prefrontal cortex is a brain stimulation technique widely used to treat depression. BDNF serum concentrations have been shown to be decreased in patients with major depressive disorder and can be upregulated by several antidepressive treatment strategies including repetitive TMS.

METHODS

In this study we were interested whether acute TMS evolves effects on serum BDNF concentrations in 42 healthy volunteers.

RESULTS

Mean BDNF serum concentration in 19 male and 23 female volunteers was 10.70+/-3.6 ng/ml (n=42) at baseline, and 10.76+/-3.9 ng/ml (n=42) after TMS treatment. BDNF serum levels did not change after acute TMS (n=42, Z=-0.44, p=0.965). BDNF serum concentrations at baseline did not differ between male (n=19, 10.05+/-2.6 ng/ml) and female (n=23, 11.25+/-4.27 ng/ml) participants of the study (n=42, Z=-0.91, p=0.363).

CONCLUSIONS

Our result suggests that TMS does not change BDNF serum concentrations immediately in healthy human volunteers.

Positive predictors for antidepressive response to prefrontal repetitive transcranial magnetic stimulation (rTMS)

Repetitive transcranial magnetic stimulation (rTMS) is a brain stimulation technique which had recently been investigated as a putative antidepressant intervention. However, there is little agreement about clinically useful predictors of rTMS outcome. Therefore, the objective of the present study was to determine whether specific biographical, clinical, and psychopathological parameters are associated with the antidepressant response to rTMS in a large sample of 70 depressive patients. We performed a logistic regression analysis in 70 patients with major depressive disorder treated with rTMS of the left dorsolateral prefrontal cortex testing the predictive value of various domains of the depression syndrome as well as the variables episode duration, degree of treatment resistance, and CORE criteria. Response was defined as a 50% reduction of the initial Hamilton score (HAMD). After two weeks of treatment, 21% of the patients showed a response to rTMS. The binary logistic regression model correctly assigned 86.7% of the responders and 96.4% of the non-responders to their final response group. In the model, a high level of sleep disturbances was a significant predictor for treatment response to rTMS. Also, a low score of treatment resistance and a short duration of episode were positive predictors. These findings provide new evidence that especially pronounced sleep disturbances may be a significant clinical predictor of a response to rTMS. Prospective rTMS studies are necessary to validate the predictive value of the derived model.

Sex differences in antidepressant-like effect of chronic repetitive transcranial magnetic stimulation in rats

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neurophysiological technique. Pre-clinical and clinical studies supported that rTMS might have antidepressant effects. However, whether antidepressant effect of chronic rTMS is gender-dependent is still unknown. In this study, male and female Wistar rats received 10-day rTMS (4 trains of 15 Hz; 200 stimuli/day; 1.0 T) or control condition, and then were subjected to the forced-swim test (FST). We found that female rats consistently showed higher activity levels than males in FST and revealed the significant effects of gender and rTMS as well as the interaction of gender and rTMS. The result suggested the antidepressant-like effects of chronic rTMS on behavioral components in FST are gender-dependent. The gender discrepancy related to rTMS should not be neglected in antidepressant treatment of rTMS.

Efficacité de la stimulation magnétique transcrânienne (rTMS) dans le traitement de la dépression : revue de la littérature

INTRODUCTION

In 1985, Barker et al. showed that it was possible to stimulate both nerves and brain using external magnetic stimulation without significant pain. During the past 10 years, therapeutic effects of repeated Transcranial Magnetic Stimulation (rTMS) have been widely studied in psychiatry and its efficacy has been demonstrated in the treatment of major depressive disorders, particularly as an alternative to electroconvulsivotherapy (ECT). Facing the large range of studies, we found necessary to propose an up-to-date review in French of the methodological and therapeutic variations among them.

METHOD

Based on an exhaustive consultation of Medline data and the Avery-George-Holtzheimer Database of rTMS Depression-Studies, supplemented by a manual research, only works evaluating the therapeutic efficacy of rTMS on depressive symptoms were retained, excluding all studies exclusively investigating the stimulation parameters or the tolerance as well as case reports.

RESULTS

Out the 66 available reports we retained 30 studies. After a description of the main results of these 30 studies, several elements of the 66 will be discussed. Open studies demonstrated that short courses rTMS (5 to 10 sessions) produced a decrease in the mean Hamilton Depression Ratting Scale (HDRS) scores, although significant remission of depression in individuals was rare. Most authors had used high frequency rTMS applied to the left Dorso Lateral Prefrontal Cortex (left DLPFC). However, low frequency rTMS applied to the right DLPFC was also followed by significant reduction of HDRS scores. Parallel arm, double blind versus placebo studies are designed to clarify the therapeutic efficacy of rTMS therapy but conclude in contradicting results. Literature data globally confirms a greater efficacy of rTMS compared to placebo (37% responders in the active group vs 20% in the sham). This efficacy could in fact be even greater because the sham procedure is disputable in most studies. Indeed, positioning rTMS coil at 45 or 90 from the scalp may not represent an accurate sham procedure and the use of real sham coil is to be recommended. Only one study has suggested that associating rTMS and ECT could decrease the number of general anesthesia required. Therapeutic efficacy has been shown by either inhibiting the right DLPFC or by stimulating the left DLPFC, although some patients exhibit paradoxical responses. High frequency rTMS (>5 Hz) increases cortical excitability and metabolism, while low-frequency rTMS stimulation ( 1 Hz) has the opposite effect. Other parameters are: relevant: intensity (from 80 to 110% of motor threshold), total number of stimulations (from 120 to 2 000) and total number of rTMS sessions (from 5 to 20). As suggested in most recent studies, higher-intensity pulses, higher number of stimulation or longer treatment courses may be more effective. Greater responsiveness to rTMS may be predicted by several patients' factors, including the absence of psychosis, younger age and previous response to rTMS therapy.

DISCUSSION

Conclusions on these factors and others, such as the importance of anatomically accurate coil placement and the distance from the coil to the brain, await further investigation. Despite heterogeneity of these reports according to methodology and treatment parameters, the antidepressive properties of rTMS now appear obvious, opening interesting prospects, in particular in the treatment of pharmacoresistant major depressive patients and, we hope, administered as adjuvant therapy in non-resistant depression.

CONCLUSION

Thus, many questions remain unanswered concerning the optimal stimulation parameters, privileged indications and maintenance sessions. This justifies the development of structured evaluation trials on larger samples.

The burden of severe depression: a review of diagnostic challenges and treatment alternatives

Among the factors making recognition of severe depression problematic for clinicians are the heterogeneous nature of the condition, lack of standardized definitions, and concomitant comorbidities that confound differential diagnosis of symptoms. The spectrum of severity in depressive disorders is extraordinarily broad, and severity assessment is comprised of several metrics including symptom intensity, diagnostic subtypes, suicidality risk, and hospitalization status. The overall diagnosis is achieved through consideration of symptom types and severities together with the degree of functional impairment as assessed by the psychiatric interview. It is likely that no single fundamental neurobiological defect underlies severe depression. The chronicity and heterogeneity of this disorder lead to frequent clinic visits and a longer course of treatment; therefore, successful approaches may require an arsenal of treatments with numerous mechanisms of action. The categories of drugs used to treat severe depression are detailed herein, as are several non-pharmacologic options including a number of experimental treatments. Pharmacotherapies include tricyclic antidepressants, selective serotonin reuptake inhibitors, atypical antidepressants such as serotonin-norepinephrine reuptake inhibitors and monoamine oxidase inhibitors, and combination and augmentation therapies. Drugs within each class are not equivalent, and efficacy may vary with symptom severity. Patient adherence makes tolerability another critical consideration in antidepressant choice. The role of non-pharmacological treatments such as electroconvulsive therapy, vagus nerve stimulation, transcranial magnetic stimulation, and deep brain stimulation remain active avenues of investigation. Improved knowledge and treatment approaches for severe depression are necessary to facilitate remission, the ideal treatment goal.

Efficacy of repetitive transcranial magnetic stimulation in depression: a review of the evidence

Repetitive transcranial magnetic stimulation (rTMS) is a novel treatment in psychiatry. We reviewed all published evidence on the efficacy of this treatment option in depressive disorders. An extensive electronic and manual search for eligible research reports identified only 12 studies that met the predetermined criteria for inclusion. rTMS was administered differently in most studies, and patient characteristics varied widely. A formal meta-analysis of the studies was thus not possible. Instead, we conducted a qualitative evaluation of the included studies. The antidepressive efficacy was not consistent, and where efficacy was demonstrated, it was modest in most studies. Some patients had good but transient responses to rTMS. Treatment gains were not maintained beyond the treatment period. Comparisons with electroconvulsive therapy (ECT) indicated the superiority of ECT. More, larger and more carefully designed studies are needed to demonstrate convincingly a clinically relevant effect of rTMS. We conclude that there is insufficient evidence for rTMS as a valid treatment for depression at present.

Transcranial magnetic stimulation: a new tool in the fight against depression

Since its introduction to the clinical realm in 1985, transcranial magnetic stimulation (TMS) has rapidly developed into a tool for exploring central nervous system function in both health and disease. The antidepressant effects of TMS were initially observed in 1993. Since then, a solid body of evidence has accumulated suggesting antidepressant effects for both slow TMS (sTMS) and repetitive TMS (rTMS). This review is divided into four parts. First, it addresses the basic concepts governing TMS, and then, second, it discusses the technical parameters involved in administering TMS. Knowledge of these parameters is necessary for understanding how TMS is administered, and how manipulation of the technique impacts on the results obtained. Third, we review the most relevant studies on the antidepressant effects of sTMS and rTMS published to date. Finally, we discuss cortical excitability and how the understanding of this basic neurophysiological function of cortical neurons can be used for monitoring the effects of TMS. In our discussion, we conclude that the time has arrived for TMS to be offered to depressed patients as a treatment.

Transcranial magnetic stimulation for treating depression

BACKGROUND

Transcranial magnetic stimulation can either excite or inhibit cortical areas of the brain, depending on whether the speed of the repetitive stimulation is applied at high or low frequencies. It has been used for physiological studies and it has also been proposed as a treatment for depression.

OBJECTIVES

To assess the clinical efficacy and safety of transcranial magnetic stimulation for treating depression.

SEARCH STRATEGY

An electronic search was performed including the Cochrane Collaboration Depression, Neurosis and Anxiety Review Group trials register (last searched June, 2001), the Cochrane Controlled Trials Register (Issue 2, 2001), MEDLINE (1966-2001), EMBASE (1974-2001), PsycLIT (1980-2001), and bibliographies from reviewed articles. Unpublished data and grey literature were searched through personal communications with researchers.

SELECTION CRITERIA

Randomised controlled trials assessing the therapeutic efficacy and safety of transcranial magnetic stimulation for depression.

DATA COLLECTION AND ANALYSIS

All reviewers independently extracted the information and verified it by cross-checking. Disagreements were resolved through discussion. Continuous data: When similar studies were grouped, the overall standardised mean difference was calculated under a fixed effect model weighted by the inverse variance method with 95% confidence intervals. (In the presence of statistical heterogeneity, a random effects model was to be used.)

MAIN RESULTS

Sixteen trials were included in the review and fourteen contained data in a suitable form for quantitative analysis. Most comparisons did not show differences between rTMS and other interventions. No difference was seen between rTMS and sham TMS using the Beck Depression Inventory or the Hamilton Depression Rating Scale, except for one time period (after two weeks of treatment) for left dorsolateral prefrontal cortex and high frequency; and also for right dorsolateral prefrontal cortex and low frequency, both in favour of rTMS and both using the Hamilton scale. Comparison of rTMS (left dorsolateral prefrontal cortex and high frequency) with electroconvulsive therapy showed no difference except for psychotic patients after two weeks treatment, using the Hamilton scale, which indicated that electroconvulsive therapy was more effective than rTMS.

REVIEWER'S CONCLUSIONS

The information in this review suggests that there is no strong evidence for benefit from using transcranial magnetic stimulation to treat depression, although the small sample sizes do not exclude the possibility of benefit.

Low frequency rTMS as an add-on antidepressive strategy: heterogeneous impact on 99mTc-HMPAO and 18 F-FDG uptake as measured simultaneously with the double isotope SPECT technique. Pilot study

Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are examination procedures that have shown that repetitive transcranial magnetic stimulation (rTMS) is biologically active. The aim of the present study was to investigate the patterns of regional cerebral 18F-fluorodeoxyglucose (18F-FDG) uptake and regional 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) uptake simultaneously during a series of therapeutic rTMS at low frequency. Four drug-resistant depressed patients underwent 10 rTMS as an add-on measure over 14 days. One day before and one day after TMS, simultaneous measurements of 18F-FDG, representing regional cerebral metabolic rate (rCMR), and 99mTc-HMPAO, representing regional cerebral blood flow (rCBF), were carried out. A conventional double head SPECT camera with 511 keV collimators was used. Statistically significant simultaneous overall changes of rCBF and rCMR were found in the upper prefrontal regions bilaterally in terms of increased uptake rates and in the left gyrus frontalis inferior in terms of decreased uptake rates of both isotopes compared to controls. Although this method improves our understanding of rTMS mechanism, there are limitations due to the lower resolution provided. Therapeutic rTMS seems to influence distinct, cortical regions affecting rCBF and rCMR.