A controlled study of repetitive transcranial magnetic stimulation in medication-resistant major depression

The effects of intermittent theta burst stimulation (iTBS) on resting-state brain entropy (BEN)

Intermittent theta burst stimulation (iTBS), a novel protocol within repetitive transcranial magnetic stimulation (rTMS), has shown superior therapeutic effects for depression compared to conventional high-frequency rTMS (HF-rTMS). However, the neural mechanisms underlying iTBS remain poorly understood. Brain entropy (BEN), a measure of the irregularity of brain activity, has recently emerged as a promising marker for regional brain function and has demonstrated sensitivity to depression and HF-rTMS. Given its potential, BEN may help elucidate the mechanisms of iTBS. In this study, we computed BEN using resting-state fMRI data from sixteen healthy participants obtained from OpenNeuro. Participants underwent iTBS over the left dorsolateral prefrontal cortex (L-DLPFC) at two different intensities (90 ​% and 120 ​% of resting motor threshold (rMT)) on separate days. We used a 2 ​× ​2 repeated measures analysis of variance (ANOVA) to analyze the interaction between iTBS stimulation intensity and the pre- vs. post-stimulation effects on BEN and paired sample t-tests to examine the specific BEN effects of iTBS at different intensities. Additionally, spatial correlation analysis was conducted to determine whether iTBS altered the baseline coupling between BEN and neurotransmitter receptors/transporters, to investigate potential neurotransmitter changes induced by iTBS. Our results indicate that subthreshold iTBS (90 ​% rMT) reduced striatal BEN, while suprathreshold iTBS (120 ​% rMT) increased it. Subthreshold iTBS led to changes in the baseline coupling between BEN and several neurotransmitter receptor/transporter maps, primarily involving serotonin (5-HT), cannabinoid (CB), acetylcholine (ACh), and glutamate (Glu). Our findings suggest that BEN is sensitive to the effects of iTBS, with different stimulation intensities having distinct effects on neural activity. Notably, subthreshold iTBS may offer more effective stimulation. This research highlights the crucial role of stimulation intensity in modulating brain activity and lays the groundwork for future clinical studies focused on optimizing therapeutic outcomes through precise stimulation intensity.

Neurostimulation to Improve Cognitive Flexibility

Cognitive flexibility, the capacity to adapt behaviors in response to changing environments, is impaired across mental illnesses, including depression, anxiety, addiction, and obsessive-compulsive disorder. Cortico-striatal-cortical circuits are integral to cognition and goal-directed behavior and disruptions in these circuits are linked to cognitive inflexibility in mental illnesses. We review evidence that neurostimulation of these circuits can improve cognitive flexibility and ameliorate symptoms, and that this may be a mechanism of action of current clinical therapies. Further, we discuss how animal models can offer insights into the mechanisms underlying cognitive flexibility and effects of neurostimulation. We review research from animal studies that may, if translated, yield better approaches to modulating flexibility. Future research should focus on refining definitions of cognitive flexibility, improving detection of impaired flexibility, and developing new methods for optimizing neurostimulation parameters. This could enhance neurostimulation therapies through more personalized treatments that leverage cognitive flexibility to improve patient outcomes.

More rTMS pulses or more sessions? The impact on treatment outcome for treatment resistant depression

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is effective for treatment-resistant depression (TRD). Optimal rTMS parameters remain unclear, especially whether number of sessions or amount of pulses contribute more to treatment outcome. We hypothesize that treatment outcome depends on the number of sessions rather than on the amount of pulses.

METHODS

We searched databases for randomized clinical trials (RCTs) on high-frequent (HF) or low-frequent (LF)-rTMS targeting the left or right DLPFC for TRD. Treatment efficacy was measured using standardized mean difference (SMD), calculated from pre- and post-treatment depression scores. Meta-regressions were used to explore linear associations between SMD and rTMS pulses, pulses/session and sessions for HF and LF-rTMS, separately for active and sham-rTMS. If these variables showed no linear association with SMD, we divided the data into quartiles and explored subgroup SMDs.

RESULTS

Eighty-seven RCTs were included: 67 studied HF-rTMS, eleven studied LF-rTMS, and nine studied both. No linear association was found between SMD and amount of pulses or pulses/session for HF and LF-rTMS. Subgroup analyses showed the largest SMDs for 1200-1500 HF-pulses/session and 360-450 LF-pulses/session. The number of sessions was significantly associated with SMD for active HF (β = 0.09, p < 0.05) and LF-rTMS (β = 0.06, p < 0.01). Thirty was the maximal number of sessions, in the included RCTs.

CONCLUSION

More rTMS sessions, but not more pulses, were associated with improved treatment outcome, in both HF and LF-rTMS. Our findings suggest that 1200-1500 HF-pulses/session and 360-450 LF-pulses/session are already sufficient, and that a treatment course should consist of least 30 sessions for higher chance of response.

Perceived stress and brain connectivity in subthreshold depression: Insights from eyes-closed and eyes-open states

Perceived stress is an acknowledged risk factor for subthreshold depression (StD), and fluctuations in perceived stress are thought to disrupt the harmony of brain networks essential for emotional and cognitive functioning. This study aimed to elucidate the relationship between eye-open (EO) and eye-closed (EC) states, perceived stress, and StD. We recruited 27 individuals with StD and 33 healthy controls, collecting resting state fMRI data under both EC and EO conditions. We combined intrinsic connectivity and seed-based functional connectivity analyses to construct the functional network and explore differences between EC and EO conditions. Graph theory analysis revealed weakened connectivity strength in the right superior frontal gyrus (SFG) and right median cingulate and paracingulate gyrus (MCC) among participants with StD, suggesting an important role for these regions in the stress-related emotions dysregulation. Notably, altered SFG connectivity was observed to significantly relate to perceived stress levels in StD, and the SFG connection emerges as a neural mediator potentially influencing the relationship between perceived stress and StD. These findings highlight the role of SFG and MCC in perceived stress and suggest that understanding EC and EO states in relation to these regions is important in the neurobiological framework of StD. This may offer valuable perspectives for early prevention and intervention strategies in mental health disorders.

Response trajectory to left dorsolateral prefrontal rTMS in major depressive disorder: A systematic review and meta-analysis: Trajectory of rTMS

The depression response trajectory after a course of repetitive transcranial magnetic stimulation(rTMS) remains understudied. We searched for blinded randomized controlled trials(RCTs) that examined conventional rTMS over left dorsolateral prefrontal cortex(DLPFC) for major depressive episodes(MDE). The effect size was calculated as the difference in depression improvement, between active and sham rTMS. We conducted a random-effects dose-response meta-analysis to model the response trajectory from the beginning of rTMS to the post-treatment follow-up phase. The area under curve (AUC) of the first 8-week response trajectory was calculated to compare antidepressant efficacy between different rTMS protocols. We included 40 RCTs(n = 2012). The best-fitting trajectory model exhibited a logarithmic curve(X2=17.7, P < 0.001), showing a gradual ascent with tapering off around the 3-4th week mark and maintaining until week 16. The maximum effect size was 6.1(95 %CI: 1.25-10.96) at week 16. The subgroup analyses showed distinct trajectories across different rTMS protocols. Besides, the comparisons of AUC showed that conventional rTMS protocols with more pulse/session group or more total pulses were associated with greater efficacy than those with fewer pulse/session or fewer total pulses, respectively. A course of conventional left DLPFC rTMS could lead to both acute antidepressant effects and sustained after-effects, which were modeled by different rTMS protocols in MDE.

High-frequency repetitive transcranial magnetic stimulation improves depressive-like behaviors in CUMS-induced rats by modulating astrocyte GLT-1 to reduce glutamate toxicity

Impaired glutamate recycling plays an important role in the pathophysiology of depression, and it has been demonstrated that glutamate transporter-1 (GLT-1) on astrocytes is involved in glutamate uptake. Studies have shown that repetitive transcranial magnetic stimulation (rTMS) is effective in treating depression, however, the exact mechanism of rTMS treatment remains unclear. Here, we used a chronic unpredictable mild stress (CUMS) protocol to induce depression-like behaviors in rats followed by rTMS treatment. Behavioral assessment was primarily through SPT, FST, OFT and body weight. Histological analysis focused on GFAP and GLT-1 expression, synaptic plasticity, apoptosis and PI3K/Akt/CREB pathway-related proteins. The results showed that rTMS treatment increased sucrose preference, improved locomotor activity, shortened immobility time as well as increased body weight. And rTMS intervention reversed the elevated glutamate concentration in the hippocampus of CUMS rats using an ELISA kit. Moreover, rTMS ameliorated the reduction in GFAP and GLT-1 expression, alleviated the decrease in BDNF, PSD95 and synapsin-1 expression, also reversed the expression levels of BAX and Bcl2 in the hippocampus of CUMS-induced rats. Moreover, rTMS also increased the protein phosphorylation level of PI3K/Akt/CREB pathway. These results suggest that rTMS treatment ameliorates depression-like behaviors in the rat model by reversing the reduction of GLT-1 on astrocytes and reducing glutamate accumulation in the synaptic cleft, which in turn ameliorates synaptic plasticity damage and neuronal apoptosis. The regulation of GLT-1 by rTMS may be through the PI3K/Akt/CREB pathway.

Systematic cross-species comparison of prefrontal cortex functional networks targeted via Transcranial Magnetic Stimulation

Transcranial Magnetic Stimulation (TMS) is a non-invasive brain stimulation method that safely modulates neural activity in vivo. Its precision in targeting specific brain networks makes TMS invaluable in diverse clinical applications. For example, TMS is used to treat depression by targeting prefrontal brain networks and their connection to other brain regions. However, despite its widespread use, the underlying neural mechanisms of TMS are not completely understood. Non-human primates (NHPs) offer an ideal model to study TMS mechanisms through invasive electrophysiological recordings. As such, bridging the gap between NHP experiments and human applications is imperative to ensure translational relevance. Here, we systematically compare the TMS-targeted functional networks in the prefrontal cortex in humans and NHPs. To conduct this comparison, we combine TMS electric field modeling in humans and macaques with resting-state functional magnetic resonance imaging (fMRI) data to compare the functional networks targeted via TMS across species. We identified distinct stimulation zones in macaque and human models, each exhibiting variations in the impacted networks (macaque: Frontoparietal Network, Somatomotor Network; human: Frontoparietal Network, Default Network). We identified differences in brain gyrification and functional organization across species as the underlying cause of found network differences. The TMS-network profiles we identified will allow researchers to establish consistency in network activation across species, aiding in the translational efforts to develop improved TMS functional network targeting approaches.

Repetitive Transcranial Magnetic Stimulation With and Without Text4Support for the Treatment of Resistant Depression: Protocol for a Patient-Centered Multicenter Randomized Controlled Pilot Trial

BACKGROUND

Treatment-resistant depression (TRD) is the inability of a patient with major depressive disorder (MDD) to accomplish or achieve remission after an adequate trial of antidepressant treatments. Several combinations and augmentation treatment strategies for TRD exist, including the use of repetitive transcranial magnetic stimulation (rTMS), and new therapeutic options are being introduced. Text4Support, a text message-based form of cognitive behavioral therapy that allows patients with MDD to receive daily supportive text messages for correcting or altering negative thought patterns through positive reinforcement, may be a useful augmentation treatment strategy for patients with TRD. It is however currently unknown if adding the Text4Support intervention will enhance the response of patients with TRD to rTMS treatment.

OBJECTIVE

This study aims to assess the initial comparative clinical effectiveness of rTMS with and without the Text4Support program as an innovative patient-centered intervention for the management of patients diagnosed with TRD.

METHODS

This study is a multicenter, prospective, parallel-design, 2-arm, rater-blinded randomized controlled pilot trial. The recruitment process is scheduled to last 12 months. It will involve active treatment for 6 weeks, observation, and a follow-up period of 6 months for participants in the study arms. In total, 200 participants diagnosed with TRD at rTMS care clinics in Edmonton, Alberta, and rTMS clinics in Halifax, Nova Scotia will be randomized to 1 of 2 treatment arms (rTMS sessions alone or rTMS sessions plus Text4Support intervention). Participants in each group will be made to complete evaluation measures at baseline, and 1, 3, and 6 months. The primary outcome measure will be the mean change in the scores of the Patient Health Questionnaire-9 (PHQ-9). The secondary outcome measures will involve the scores of the 7-item Generalized Anxiety Disorders Scale (GAD-7), Columbia-Suicide Severity Rating Scale (CSSRS), and World Health Organization-Five Well-Being Index (WHO-5). Patient data will be analyzed with descriptive statistics, repeated measures, and correlational analyses. Qualitative data will be analyzed using the thematic analysis framework.

RESULTS

The results of the study are expected to be available 18 months from the start of recruitment. We hypothesize that participants enrolled in the rTMS plus Text4Support intervention treatment arm of the study will achieve superior outcomes compared with the outcomes of participants enrolled in the rTMS alone arm.

CONCLUSIONS

The application of the combination of rTMS and Text4Support has not been investigated previously. Therefore, we hope that this study will provide a concrete base of data to evaluate the practical application and efficacy of using the novel combination of these 2 treatment modalities.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/46830.

An Evaluation of the Effectiveness of Repetitive Transcranial Magnetic Stimulation (rTMS) for the Management of Treatment-Resistant Depression with Somatic Attributes: A Hospital-Based Study in Oman

Depressive illnesses in non-Western societies are often masked by somatic attributes that are sometimes impervious to pharmacological agents. This study explores the effectiveness of repetitive transcranial magnetic stimulation (rTMS) for people experiencing treatment-resistant depression (TRD) accompanied by physical symptoms. Data were obtained from a prospective study conducted among patients with TRD and some somatic manifestations who underwent 20 sessions of rTMS intervention from January to June 2020. The Hamilton Rating Scale for Depression (HAMD) was used for clinical evaluation. Data were analysed using descriptive and inferential techniques (multiple logistic regression) in SPSS. Among the 49 participants (mean age: 42.5 ± 13.3), there was a significant reduction in posttreatment HAMD scores compared to baseline (t = 10.819, p < 0.0001, and 95% CI = 8.574-12.488), indicating a clinical response. Approximately 37% of the patients responded to treatment, with higher response rates among men and those who remained in urban areas, had a history of alcohol use, and were subjected to the standard 10 HZ protocol. After adjusting for all extraneous variables, the rTMS protocol emerged as the only significant predictor of response to the rTMS intervention. To our knowledge, this is the first study to examine the effectiveness of rTMS in the treatment of somatic depression.

Association between daily dose and efficacy of rTMS over the left dorsolateral prefrontal cortex in depression: A meta-analysis

Repetitive transcranial magnetic stimulation (rTMS) is a well-established, safe, and effective brain stimulation technique for depression; however, uniform parameters have not been used in clinical practice. The aim of this study was to identify the parameters that affect rTMS effectiveness and ascertain the range in which that parameter has optimal efficacy. A meta-analysis of sham-controlled trials using rTMS delivered over the left dorsolateral prefrontal cortex (DLPFC) in depression was conducted. In the meta-regression and subgroup analyses, all rTMS stimulation parameters were extracted and their association with efficacy was investigated. Of the 17,800 references, 52 sham-controlled trials were included. Compared to sham controls, our results demonstrated a significant improvement in depressive symptoms at the end of treatment. According to the results of meta-regression, the number of pulses and sessions per day correlated with rTMS efficacy; however, the positioning method, stimulation intensity, frequency, number of treatment days, and total pulses did not. Furthermore, subgroup analysis revealed that the efficacy was correspondingly better in the group with higher daily pulses. In clinical practice, increasing the number of daily pulses and sessions may improve the effectiveness of rTMS.

Examining the neural mechanisms of rTMS: a naturalistic pilot study of acute and serial effects in pharmacoresistant depression

Introduction

Previous studies have demonstrated the effectiveness of therapeutic repetitive transcranial magnetic stimulation (rTMS) to treat pharmacoresistant depression. Nevertheless, these trials have primarily focused on the therapeutic and neurophysiological effects of rTMS following a long-term treatment course. Identifying brain-based biomarkers of early rTMS therapeutic response remains an important unanswered question. In this pilot study, we examined the effects of rTMS on individuals with pharmacoresistant depression using a graph-based method, called Functional Cortical Networks (FCN), and serial electroencephalography (EEG). We hypothesized that changes in brain activity would occur early in treatment course.

Methods

A total of 15 patients with pharmacoresistant depression underwent five rTMS sessions (5Hz over the left dorsolateral prefrontal cortex, 120%MT, up to 4,000 pulses/session). Five participants received additional rTMS treatment, up to 40 sessions. Resting EEG activity was measured at baseline and following every five sessions, using 64-channel EEG, for 10 minutes with eyes closed. An FCN model was constructed using time-varying graphs and motif synchronization. The primary outcome was acute changes in weighted-node degree. Secondary outcomes included serial FFT-based power spectral analysis and changes in depressive symptoms measured by the 9-Item Patient Health Questionnaire (PHQ-9) and the 30-item Inventory of Depressive Symptoms-Self Report (IDS-SR).

Results

We found a significant acute effect over the left posterior area after five sessions, as evidenced by an increase in weighted-node degree of 37,824.59 (95% CI, 468.20 to 75,180.98) and a marginal enhancement in the left frontal region (t (14) = 2.0820, p = 0.056). One-way repeated measures ANOVA indicated a significant decrease in absolute beta power over the left prefrontal cortex (F (7, 28) = 2.37, p = 0.048) following ten rTMS sessions. Furthermore, a significant clinical improvement was observed following five rTMS sessions on both PHQ-9 (t (14) = 2.7093, p = 0.017) and IDS-SR (t (14) = 2.5278, p = 0.024) and progressed along the treatment course.

Discussion

Our findings suggest that FCN models and serial EEG may contribute to a deeper understanding of mechanisms underlying rTMS treatment. Additional research is required to investigate the acute and serial effects of rTMS in pharmacoresistant depression and assess whether early EEG changes could serve as predictors of therapeutic rTMS response.

A Systematic Review Assessing Patient-Related Predictors of Response to Transcranial Magnetic Stimulation in Major Depressive Disorder

Objective

The safety and efficacy of transcranial magnetic stimulation (TMS) in the acute treatment of major depressive disorder (MDD) is well established. However, it is not well understood which patient-related factors are associated with a more robust antidepressant response. Identifying predictive factors for therapeutic response to TMS treatment in depression will guide clinicians in patient selection.

Methods

By systematic review of clinical trial data, the current study aims to identify and analyze reported patient-specific predictors of response to an acute course of TMS treatment for MDD. PubMed was searched for randomized controlled trials of TMS for patients with depression. Studies were appraised for risk of bias using components recommended by the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Results

TMS data were available from 375 studies, 18 of which were included in this review. Treatment response is inversely associated with treatment refractoriness and age.

Conclusion

Inadequate sample size and large heterogeneity in study parameters among clinical trials limit any strong conclusions from being drawn; nonetheless, despite these limitations, there is mounting evidence, which points to age and treatment refractoriness as candidate variables for predicting clinical outcome. Implications of these findings for treatment of MDD are discussed.

Alpha transcranial alternating current stimulation reduces depressive symptoms in people with schizophrenia and auditory hallucinations: a double-blind, randomized pilot clinical trial

People with schizophrenia exhibit reduced alpha oscillations and frontotemporal coordination of brain activity. Alpha oscillations are associated with top-down inhibition. Reduced alpha oscillations may fail to censor spurious endogenous activity, leading to auditory hallucinations. Transcranial alternating current stimulation (tACS) at the alpha frequency was shown to enhance alpha oscillations in people with schizophrenia and may thus be a network-based treatment for auditory hallucinations. We conducted a double-blind, randomized, placebo-controlled pilot clinical trial to examine the efficacy of 10-Hz tACS in treating auditory hallucinations in people with schizophrenia. 10-Hz tACS was administered in phase at the dorsolateral prefrontal cortex and the temporoparietal junction with a return current at Cz. Patients were randomized to receive tACS or sham for five consecutive days during the treatment week (40 min/day), followed by a maintenance period, during which participants received weekly tACS (40 min/visit) or sham. tACS treatment reduced general psychopathology (p < 0.05, Cohen's d = -0.690), especially depression (p < 0.005, Cohen's d = -0.806), but not auditory hallucinations. tACS treatment increased alpha power in the target region (p < 0.05), increased the frequency of peak global functional connectivity towards 10 Hz (p < 0.05), and reduced left-right frontal functional connectivity (p < 0.005). Importantly, changes in brain functional connectivity significantly correlated with symptom improvement (p < 0.05). Daily 10 Hz-tACS increased alpha power and altered alpha-band functional connectivity. Successful target engagement reduced depression and other general psychopathology symptoms, but not auditory hallucinations. Considering existing research of 10Hz tACS as a treatment for major depressive disorder, our study demonstrates its transdiagnostic potential for treating depression.

Cross-attractor repertoire provides new perspective on structure-function relationship in the brain

The brain exhibits complex intrinsic dynamics, i.e., spontaneously arising activity patterns without any external inputs or tasks. Such intrinsic dynamics and their alteration are thought to play crucial roles in typical as well as atypical cognitive functioning. Linking the ever-changing intrinsic dynamics to the rather static anatomy is a challenging endeavor. Dynamical systems models are important tools for understanding how structure and function are linked in the brain. Here, we provide a novel modeling framework to examine how functional connectivity depends on structural connectivity in the brain. Existing modeling frameworks typically focus on noise-driven (or stochastic) dynamics near a single attractor. Complementing existing approaches, we examine deterministic features of the distribution of attractors, in particular, how regional states are correlated across all attractors - cross-attractor coordination. We found that cross-attractor coordination between brain regions better predicts human functional connectivity than noise-driven single-attractor dynamics. Importantly, cross-attractor coordination better accounts for the nonlinear dependency of functional connectivity on structural connectivity. Our findings suggest that functional connectivity patterns in the brain may reflect transitions between attractors, which impose an energy cost. The framework may be used to predict transitions and energy costs associated with experimental or clinical interventions.

The Association Between Sample and Treatment Characteristics and the Efficacy of Repetitive Transcranial Magnetic Stimulation in Depression: A Meta-analysis and Meta-regression of Sham-controlled Trials

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a form of non-invasive neuromodulation that is increasingly used to treat major depressive disorder (MDD). However, treatment with rTMS could be optimized by identifying optimal treatment parameters or characteristics of patients that are most likely to benefit. This meta-analysis and meta-regression aims to identify sample and treatment characteristics that are associated with change in depressive symptom level, treatment response and remission.

METHODS

The databases PubMed, Embase, Web of Science and Cochrane library were searched for randomized controlled trials (RCTs) reporting on the therapeutic efficacy of high-frequent, low-frequent, or bilateral rTMS for MDD compared to sham. Study and sample characteristics as well as rTMS parameters and outcome variables were extracted. Effect sizes were calculated for change in depression score and risk ratios for response and remission.

RESULTS

Sixty-five RCTs with a total of 2982 subjects were included in this meta-analysis. Active rTMS resulted in a larger depressive symptom reduction than sham protocol (Hedges' g = -0.791 95% CI -0.977; -0.605). Risk ratios for response and remission were 2.378 (95% CI 1.882; 3.005) and 2.450 (95% CI 1.779; 3.375), respectively. We found no significant association between sample and treatment parameters and rTMS efficacy.

CONCLUSIONS

rTMS is an efficacious treatment for MDD. No associations between sample or treatment characteristics and efficacy were found, for which we caution that publication bias, heterogeneity and lack of consistency in the definition of remission might bias these latter null findings. Our results are clinically relevant and support the use of rTMS as a non-invasive and effective treatment option for depression.

How Far Has Repetitive Transcranial Magnetic Stimulation Come Along in Treating Patients With Treatment-Resistant Depression?

Antidepressant drugs have been the mainstay for treating patients with major depressive disorder. However, with a rapid rise in the rates of major depressive disorder, there has been a substantial increase in the resistance to antidepressants in the last decade. This has augmented the need for alternative treatment modalities, including repetitive transcranial magnetic stimulation. This review assesses the progress repetitive transcranial magnetic stimulation has made in treating patients resistant to antidepressants. We conducted a comprehensive literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The clinical studies reviewed under the scope of this paper showed significant benefits in treatment-resistant patients. Several studies demonstrated that the prefrontal cortex's unilateral and bilateral transcranial magnetic stimulation increased the remission rates in active treatment groups compared to the control. Treatments ranged from 10 to 20 sessions, with 1,600 pulses to a maximum of 4,000 pulses in unilateral stimulation and 720 to 2,100 pulses in bilateral stimulation per session. Interestingly, bilateral stimulation utilizing fewer pulses showed notable improvement than a higher number of pulses in unilateral stimulation. However, the lack of standardized dose, dosing frequency, treatment duration, and follow-up protocols warrant further research to bring this therapy into clinical practice.

Safety of transcranial magnetic stimulation in unipolar depression: A systematic review and meta-analysis of randomized-controlled trials

BACKGROUND

To study the safety and patients' tolerance of transcranial magnetic stimulation (TMS), we conducted a systematic review and meta-analysis of the major depressive disorder population.

METHODS

Our study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched the literature published before April 30th, 2021 and performed a random-effects meta-analyses which included drop-out due to adverse events, serious adverse events and other non-serious adverse events as primary and secondary outcomes.

RESULTS

A total of 53 randomized sham-controlled trials with 3,273 participants were included. There was no increased risk of drop-out due to an adverse event (active TMS intervention group=3.3%, sham TMS intervention group=2.3%, odds ratio = 1.30, 95% CI= 0.78-2.16, P = 0.31) or a serious adverse event (active TMS intervention group=0.9%, sham TMS intervention group=1.5%, odds ratio = 0.67, 95% CI= 0.29-1.55, P = 0.35). Our findings suggest that TMS intervention may significantly increase the risk of non-serious adverse events including: headaches (active TMS intervention group=22.6%, sham TMS intervention group=16.2%, odds ratio = 1.48, 95% CI= 1.15-1.91, P = 0.002), discomfort (active TMS intervention group=10.9%, sham TMS intervention group=5.0%, odds ratio 1.98, 95% CI= 1.22-3.21, P = 0.006) and pain (active TMS intervention group=23.8%, sham TMS intervention group=5.2%, odds ratio= 8.09, 95% CI= 4.71-13.90, P < 0.001) at the stimulation site, but these non-serious events were mostly mild and transient after TMS treatment.

CONCLUSIONS

These findings provide evidence for the safety and patients' tolerance of transcranial magnetic stimulation technique as an alternative monotherapy or as an add-on treatment for major depressive disorder.

Comparative Efficacy and Acceptability of 3 Repetitive Transcranial Magnetic Stimulation Devices for Depression: A Meta-Analysis of Randomized, Sham-Controlled Trials

INTRODUCTION

Repetitive transcranial magnetic stimulation (rTMS) has been employed worldwide for therapy-resistant depression. The Food and Drug Administration has approved a number of therapeutic devices for treating major depressive disorder; however, no studies have examined the differences in efficacy and acceptability among commercially available stimulation devices. The aim of our study was to compare the efficacy and acceptability of 3 stimulation devices (NeuroStar, MagPro, and Magstim) for depressive disorders.

METHODS

Our study included 31 randomized sham-controlled trials of high-frequency rTMS included in the network meta-analysis by Brunoni. We calculated the risk ratio and 95% confidence intervals, comparing each device with sham for the endpoints of response rate, remission rate, and all-cause discontinuation. We then analyzed the differences among the devices in effect size for those endpoints.

RESULTS

After determining the effect sizes for the endpoints, we found no statistically significant subgroup differences in the response rates, all-cause discontinuation, or remission rates among the devices (p = 0.12, p = 0.84, and p = 0.07, respectively).

CONCLUSION

Our results suggest similar efficacy and acceptability for the 3 stimulation devices. Future studies need to perform head-to-head comparisons of the efficacy and acceptability of the stimulation devices for treating depression using the same stimulation protocols.

Anatomical and fMRI-network comparison of multiple DLPFC targeting strategies for repetitive transcranial magnetic stimulation treatment of depression

BACKGROUND

The efficacy of repetitive transcranial magnetic stimulation (rTMS) for depression may vary depending on the subregion stimulated within the dorsolateral prefrontal cortex (DLPFC). Clinical TMS typically uses scalp-based landmarks for DLPFC targeting, rather than individualized MRI guidance.

OBJECTIVE

In rTMS patients, determine the brain systems targeted by multiple DLPFC stimulation rules by computing several surrogate measures: underlying brain targets labeled with connectivity-based atlases, subgenual cingulate anticorrelation strength, and functionally connected networks.

METHODS

Forty-nine patients in a randomized controlled trial of rTMS therapy for treatment resistant major depression underwent structural and functional MRI. DLPFC rules were applied virtually using MR-image guidance. Underlying cortical regions were labeled, and connectivity with the subgenual cingulate and whole-brain computed.

RESULTS

Scalp-targeting rules applied post hoc to these MRIs that adjusted for head size, including Beam F3, were comparably precise, successful in directly targeting classical DLPFC and frontal networks, and anticorrelated with the subgenual cingulate. In contrast, all rules involving fixed distances introduced variability in regions and networks targeted. The 5 cm rule targeted a transitional DLPFC region with a different connectivity profile from the adjusted rules. Seed-based connectivity analyses identified multiple regions, such as posterior cingulate and inferior parietal lobe, that warrant further study in order to understand their potential contribution to clinical response.

CONCLUSION

EEG-based rules consistently targeted DLPFC brain regions with resting-state fMRI features known to be associated with depression response. These results provide a bridge from lab to clinic by enabling clinicians to relate scalp-targeting rules to functionally connected brain systems.

Day-to-day variability in motor threshold during rTMS treatment for depression: Clinical implications

BACKGROUND

When repetitive transcranial magnetic stimulation (rTMS) is used to treat medication refractory depression, the treatment pulse intensity is individualized according to motor threshold (MT). This measure is often acquired only on the first day of treatment, as per the protocol currently approved by Food and Drug Administration.

OBJECTIVE

Here, we aimed to assess daily MT variability across an rTMS treatment course and simulate the effects of different schedules of MT assessment on treatment intensity.

METHODS

We conducted a naturalistic retrospective study with 374 patients from a therapeutic rTMS program for depression that measures MT daily.

RESULTS

For each patient, in almost half the TMS sessions, MT varied on average more than 5% as compared to the baseline MT acquired in the first treatment day. Such variability was only minimally impacted by having different TMS technicians acquiring MT in different days. In a smaller cohort of healthy individuals, we confirmed that the motor hotspot localization method, a critical step for accurate MT assessment, was stable in different days, arguing that daily MT variability reflects physiological variability, rather than an artifact of measurement error. Finally, in simulations of the effect of one-time MT measurement, we found that half of sessions would have been 5% or more above or below target intensity, with almost 5% of sessions 25% above target intensity. The simulated effects of weekly MT measurements were significantly improved.

CONCLUSIONS

In conclusion, MT varies significantly across days, not fully dependent on methods of MT acquisition. This finding may have important implications for therapeutic rTMS practice regarding safety and suggests that regular MT assessments, daily or at least weekly, would ameliorate the effect.

Comparative efficacy and acceptability of neuromodulation procedures in the treatment of treatment-resistant depression: a network meta-analysis of randomized controlled trials

BACKGROUND

Nearly half of the patients with depression experience suboptimal benefits from antidepressants. Neuromodulation therapies, a kind of technology that can regulate neuronal firing activity by electrical or magnetic stimulation, were introduced to improve this situation. However, the results from clinical trials have been inconsistent.

METHODS

We followed the extension of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to perform this network meta-analysis (NMA). The results were evaluated by relative risk (RR) for the response, remission, and discontinuation rates.

RESULTS

In total, 49 trials with 2,941 patients were included in this study. Bilateral theta burst stimulation (TBS, RR 5.00, 95% CI 1.11-22.44), priming transcranial magnetic stimulation (pTMS, RR 2.97, 95% CI 1.20-7.39), low-frequency right repetitive transcranial magnetic stimulation (TMS) (LFR-rTMS, RR 2.62, 95% CI 1.56-4.39), high-frequency left repetitive TMS (HFL-rTMS, RR 2.18, 95% CI 1.52-3.13), and bilateral repetitive TMS (BL-rTMS, RR 3.08, 95% CI 1.78-5.31) were demonstrated to have higher response rates than sham control. BL-rTMS (RR 3.12, 95% CI 1.06-9.09) was found to have a higher response rate than deep brain stimulation in this NMA. All measures had the non-inferiority acceptability than the sham-control. BL-rTMS was more acceptable than bitemporal ECT (BT-ECT, RR 0.18, 95% CI 0.03-0.89), while pTMS was more acceptable than BT-ECT (RR 0.08, 95% CI 0.01-0.55), HFL-rTMS (RR 0.34, 95% CI 0.12-0.93), and deep TMS (RR 0.15, 95% CI 0.02-0.96).

CONCLUSION

Besides electroconvulsive therapy (ECT), rTMS, priming TMS, and bilateral TBS proved effective for patients with treatment-resistant depression (TRD). BL-rTMS showed high efficacy and acceptability, and bilateral TBS had the potential to be the most efficacious neuromodulation measures.

Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression: Recent Critical Advances in Patient Care

PURPOSE

Transcranial magnetic stimulation (TMS) is an evidence-based treatment for pharmacoresistant major depressive disorder (MDD). In the last decade, the field has seen significant advances in the understanding and use of this new technology. This review aims to describe the large, randomized controlled studies leading to the modern use of rTMS for MDD. It also includes a special section briefly discussing the use of these technologies during the COVID-19 pandemic.

RECENT FINDINGS

Several new approaches and technologies are emerging in this field, including novel approaches to reduce treatment time and potentially yield new approaches to optimize and maximize clinical outcomes. Of these, theta burst TMS now has evidence indicating it is non-inferior to standard TMS and provides significant advantages in administration. Recent studies also indicate that neuroimaging and related approaches may be able to improve TMS targeting methods and potentially identify those patients most likely to respond to stimulation.

SUMMARY

While new data is promising, significant research remains to be done to individualize and optimize TMS procedures. Emerging new approaches, such as accelerated TMS and advanced targeting methods, require additional replication and demonstration of real-world clinical utility. Cautious administration of TMS during the pandemic is possible with careful attention to safety procedures.

Theta burst stimulation over the prefrontal cortex: Effects on cerebral oximetry and cardiovascular measures in healthy humans

Theta Burst Stimulation (TBS) is a non-invasive neurophysiological technique, able to induce changes in synaptic activity. Research suggests that TBS may induce changes in cerebral oxygenation, cerebral blood flow, blood pressure and heart rate but there are conflicting results across studies. Thus, the objective of our sham-controlled study is to evaluate if TBS applied to the dorsolateral prefrontal cortex (DLPFC) of healthy volunteers produces changes in cerebral oximetry, heart rate and blood pressure. Forty-nine volunteers of both sexes were randomly allocated to one of five stimulation groups. Before and after real TBS or sham stimulation, blood pressure, heart rate, and cerebral oxygenation of the volunteers were measured. Cerebral oxygenation values were obtained with a near infra-red spectroscopy system. We found a significant reduction in left cortex oximetry after continuous TBS (cTBS) over the left DLPFC (p = 0.039) and a non-significant reduction in right cortex oximetry (p = 0.052). Right hemisphere inhibition (using cTBS) seemed to originate a significant reduction of 8 mmHg in systolic arterial pressure. No other changes were seen in oximetry, cardiac frequency and diastolic arterial pressure. In our group of normal subjects, cTBS applied to the left DLPFC was able to reduce oxygenation in the left cortex. Right hemisphere inhibition was associated with a significant reduction in systolic pressure.

Treatment effect variability in brain stimulation across psychiatric disorders: A meta-analysis of variance

Noninvasive brain stimulation methods such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are promising add-on treatments for a number of psychiatric conditions. Yet, some of the initial excitement is wearing off. Randomized controlled trials (RCT) have found inconsistent results. This inconsistency is suspected to be the consequence of variation in treatment effects and solvable by identifying responders in RCTs and individualizing treatment. However, is there enough evidence from RCTs that patients respond differently to treatment? This question can be addressed by comparing the variability in the active stimulation group with the variability in the sham group. We searched MEDLINE/PubMed and included all double-blinded, sham-controlled RCTs and crossover trials that used TMS or tDCS in adults with a unipolar or bipolar depression, bipolar disorder, schizophrenia spectrum disorder, or obsessive compulsive disorder. In accordance with the PRISMA guidelines to ensure data quality and validity, we extracted a measure of variability of the primary outcome. A total of 130 studies with 5748 patients were considered in the analysis. We calculated variance-weighted variability ratios for each comparison of active stimulation vs sham and entered them into a random-effects model. We hypothesized that treatment effect variability in TMS or tDCS would be reflected by increased variability after active compared with sham stimulation, or in other words, a variability ratio greater than one. Across diagnoses, we found only a minimal increase in variability after active stimulation compared with sham that did not reach statistical significance (variability ratio = 1.03; 95% CI, 0.97, 1.08, P = 0.358). In conclusion, this study found little evidence for treatment effect variability in brain stimulation, suggesting that the need for personalized or stratified medicine is still an open question.

The Investigation of the Effects of Repetitive Transcranialmagnetic Stimulation Treatment on Taste and Smell Sensations in Depressed Patients

Introduction

Loss in sense of smell and taste is a condition that can occur without an organic pathology and it is noteworthy in patients diagnosed with Major Depressive Disorder (MDD). Few studies have shown that Repetitive Transcranial Magnetic Stimulation (tTMS) can correct losses in sense of smell and taste. In this study, we aimed to examine the effects of tTMS treatment applied to patients diagnosed with MDD on the sense of smell and taste in this patient group.

Methods

The sense of smell of 56 patients who were diagnosed with MDD and had tTMS indication was examined with the "Sniffin' Sticks" smell test and the sense of taste with the "Taste Strips" taste test. MDD patients who lost at least one sense of smell and taste were included in the study, but a total of 30 patients were able to complete the study. Hamilton Depression Scale (HAM-D) was applied to the patients before tTMS treatment, and this scale was repeated after 15 sessions of tTMS treatment. Taste and smell senses were re-evaluated after the last tTMS session.

Results

According to the Sniffin Stick Smell test, 15 of 29 patients with hyposmia had normosmia after tTMS, and 16 of 18 patients who were found to have hypogeusia according to Taste Strips Taste test had Normogeusia after tTMS. There was a positive improvement in both the smell and taste scores of all patients who were treated, compared to before tTMS. The positive improvement in the smell tests of the patients who responded to the treatment according to the HAM-D scores was found to be significantly different than the patients who did not respond.

Conclusion

The positive effect of tTMS treatment on the sense of smell and taste has been demonstrated even in patients whose HAM-D scores could not be sufficiently decreased. In patients diagnosed with depression, using tTMS alone or adding it to the current treatment suggests that it may have a positive effect on the sense of smell and taste as well as depression treatment.

Sex differences in the transcription of glutamate transporters in major depression and suicide

BACKGROUND

Accumulating evidence indicates that the glutamate system contributes to the pathophysiology of major depressive disorder (MDD) and suicide. We previously reported higher mRNA expression of glutamate receptors in the dorsolateral prefrontal cortex (DLPFC) of females with MDD.

METHODS

In the current study, we measured the expression of mRNAs encoding glutamate transporters in the DLPFC of MDD subjects who died by suicide (MDD-S, n = 51), MDD non-suicide subjects (MDD-NS, n = 28), and individuals who did not have a history of neurological illness (CTRL, n = 32).

RESULTS

Females but not males with MDD showed higher expression of EAATs and VGLUTs relative to CTRLs. VGLUT expression was significantly higher in the female MDD-S group, relative to the other groups. EAAT expression was lower in the male violent suicides.

LIMITATIONS

This study has limitations common to most human studies, including medication history and demographic differences between the diagnostic groups. We mitigated the effects of confounders by including them as covariates in our analyses.

CONCLUSIONS

We report sex differences in the expression of glutamate transporter genes in the DLPFC in MDD. Increased neuronal glutamate transporter expression may increase synaptic glutamate, leading to neuronal and glial loss in the DLPFC in MDD. These deficits may lower DLPFC activity, impair problem solving and impair executive function in depression, perhaps increasing vulnerability to suicidal behavior. These data add to accumulating support for the hypothesis that glutamatergic transmission is dysregulated in MDD and suicide. Glutamate transporters may be novel targets for the development of rapidly acting antidepressant therapies.

Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression in Active-Duty Service Members Improves Depressive Symptoms

OBJECTIVES

Current research on the efficacy of repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex as a noninvasive therapy for treatment-resistant depression is largely settled science. However, little is known about its efficacy with active-duty service members (ADSMs) with major depressive disorder. In a retrospective chart review, we examined depressive symptom ratings in ADSMs seeking treatment at the US Army Outpatient Behavioral Health Service Clinic at Eisenhower Army Medical Center, Fort Gordon, Ga.

METHODS

We reviewed 121 consecutive outpatient charts, which yielded 61 ADSMs who completed a minimum of 20 rTMS sessions for refractory depression, and for whom both pretreatment and posttreatment depressive symptom ratings were available. Pre- and post-Patient Health Questionnaire 9 (PHQ-9) scores were subjected to a paired t test, and Reliable Change Indices were calculated to determine both reliable and clinical significance.

RESULTS

Average (SD) pretreatment and posttreatment PHQ-9 scores were 15.8 (6.2) and 12.6 (7.6), respectively. Statistically significant reduction in post-PHQ-9 was demonstrated (P < 0.001), with 69% of patients lowering their ratings and 31% demonstrating reliable change (improvement >5.64). Additionally, 20% demonstrated a reliable change that placed them in the nondysfunctional range (post-PHQ-9 <9.6), demonstrating clinical significance.

CONCLUSIONS

These data confirm a course of standard rTMS to ADSMs with major depression is promising in reducing depressive symptoms. Given that success and completion rates from this clinic are similar to those reported in civilian populations (80%), rTMS may be an adequate additional treatment or augmentation strategy for refractory depression in ADSMs.

Low-frequency rTMS inhibits the anti-depressive effect of ECT. A pilot study

OBJECTIVE

Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the prefrontal cortex has been shown to have a statistically and clinically significant anti-depressant effect. The present pilot study was carried out to investigate if right prefrontal low-frequency rTMS as an add-on to electroconvulsive therapy (ECT) accelerates the anti-depressant effect and reduces cognitive side effects.

METHODS

In this randomised, controlled, double-blind study, thirty-five patients with major depression were allocated to ECT+placebo or ECT+low-frequency right prefrontal rTMS. The severity of depression was evaluated during the course using the Hamilton scale for depression (the 17-item as well as the 6-item scale) and the major depression inventory (MDI). Furthermore, neuropsychological assessment of cognitive function was carried out.

RESULTS

The study revealed no significant difference between the two groups for any of the outcomes, but with a visible trend to lower scores for MDI after treatment in the placebo group. The negative impact of ECT on neurocognitive functions was short-lived, and scores on logical memory were significantly improved compared to baseline 4 weeks after last treatment. The ECT-rTMS group revealed generally less impairment of cognitive functions than the ECT-placebo group.

CONCLUSION

The addition of low-frequency rTMS as an add-on to ECT treatment did not result in an accelerated response. On the contrary, the results suggest that low-frequency rTMS could inhibit the anti-depressant effect of ECT.

Experimental evaluation of methods for real-time EEG phase-specific transcranial magnetic stimulation

OBJECTIVE

Real-time approaches for transcranial magnetic stimulation (TMS) based on a specific EEG phase are a promising avenue for more precise neuromodulation interventions. However, optimal approaches to reliably extract the EEG phase in a frequency band of interest to inform TMS are still to be identified. Here, we implement a new real-time phase detection method for closed-loop EEG-TMS for robust phase extraction. We compare this algorithm with state-of-the-art methods and evaluate its performance both in silico and experimentally.

APPROACH

We propose a new robust algorithm (Educated Temporal Prediction) for delivering real-time EEG phase-specific stimulation based on short prerecorded EEG training data. This method estimates the interpeak period from a training period and applies a bias correction to predict future peaks. We compare the accuracy and computation speed of the ETP algorithm with two existing methods (Fourier based, Autoregressive Prediction) using prerecorded resting EEG data and real-time experiments.

MAIN RESULTS

We found that Educated Temporal Prediction performs with higher accuracy than Fourier-based or Autoregressive methods both in silico and in vivo while being computationally more efficient. Further, we document the dependency of the EEG signal-to-noise ratio (SNR) on algorithm accuracy across all algorithms.

SIGNIFICANCE

Our results give important insights for real-time EEG-TMS technical development as well as experimental design. Due to its robustness and computational efficiency, our method can find broad use in experimental research or clinical applications. Through open sharing of code for all three methods, we enable broad access of TMS-EEG real-time algorithms to the community.

Suicidal behavior in treatment resistant major depressive disorder patients treated with transmagnetic stimulation(TMS) and its relationship with cognitive functions

The aim of this study is to investigate the effects of rTMS treatment on suicidal thoughts/behaviors and to determine the cognitive mechanisms underlying the effects of rTMS treatment on suicidal thoughts/behaviors in treatment-resistant depression(TRD). Thirty patients with TRD received rTMS 5 sessions per week for 4-6 weeks. Montgomery-Asberg Depression Rating Scale(MADRS), Columbia Suicide Severity Rating Scale(C-SSRS), Suicidal Ideation Scale(SIS), Beck Hopelessness Scale(BHS) and Cambridge Neuropsychological Test Automated Battery(CANTAB) were administered before and after treatment. After rTMS treatment, there was a significant decrease in depressive complaints and suicidal thoughts and improvement in emotional recognition. However, there was no significant change in cognitive functions such as cognitive flexibility, motor response inhibition and decision making. Pre-treatment decision-making and flexible thinking skills were related to the change in suicidal ideation. In TRD patients, rTMS has a positive effect on depressive symptoms and suicidal thoughts/behaviors and emotion recognition abilities. Although there is no negative effect on other cognitive functions, the positive effect of rTMS on cognitive functions is limited. At this point, we think that the TRD would be treated more effectively with treatments targeting specific symptom clusters such as other cognitive functions and suicidal thoughts.

A systematic review and meta-analysis of rTMS effects on cognitive enhancement in mild cognitive impairment and Alzheimer's disease

Repetitive transcranial magnetic stimulation (rTMS), a noninvasive brain stimulation technique, has emerged as a promising treatment for mild cognitive impairment (MCI) and Alzheimer's disease (AD). Currently, however, the effectiveness of this therapy is unclear because of the low statistical power and heterogeneity of previous trials. The purpose of the meta-analysis was to systematically characterize the effectiveness of various combinations of rTMS parameters on different cognitive domains in patients with MCI and AD. Thirteen studies comprising 293 patients with MCI or AD were included in this analysis. Random-effects analysis revealed an overall medium-to-large effect size (0.77) favoring active rTMS over sham rTMS in the improvement of cognitive functions. Subgroup analyses revealed that (1) high-frequency rTMS over the left dorsolateral prefrontal cortex and low-frequency rTMS at the right dorsolateral prefrontal cortex significantly improved memory functions; (2) high-frequency rTMS targeting the right inferior frontal gyrus significantly enhanced executive performance; and (3) the effects of 5-30 consecutive rTMS sessions could last for 4-12 weeks. Potential mechanisms of rTMS effects on cognitive functions are discussed.

Converging Resting State Networks Unravels Potential Remote Effects of Transcranial Magnetic Stimulation for Major Depression

Despite being a commonly used protocol to treat major depressive disorder (MDD), the underlying mechanism of repetitive transcranial magnetic stimulation (rTMS) on dorsolateral prefrontal cortex (DLPFC) remains unclear. In the current study, we investigated the resting-state fMRI data of 100 healthy subjects by exploring three overlapping functional networks associated with the psychopathologically MDD-related areas (the nucleus accumbens, amygdala, and ventromedial prefrontal cortex). Our results showed that these networks converged at the bilateral DLPFC, which suggested that rTMS over DLPFC might improve MDD by remotely modulating the MDD-related areas synergistically. Additionally, they functionally converged at the DMPFC and bilateral insula which are known to be associated with MDD. These two areas could also be potential targets for rTMS treatment. Dynamic causal modelling (DCM) and Granger causality analysis (GCA) revealed that all pairwise connections among bilateral DLPFC, DMPFC, bilateral insula, and three psychopathologically MDD-related areas contained significant causality. The DCM results also suggested that most of the functional interactions between MDD-related areas and bilateral DLPFC, DMPFC, and bilateral insula can predominantly be explained by the effective connectivity from the psychopathologically MDD-related areas to the rTMS stimulation sites. Finally, we found the conventional functional connectivity to be a more representative measure to obtain connectivity parameters compared to GCA and DCM analysis. Our research helped inspecting the convergence of the functional networks related to a psychiatry disorder. The results identified potential targets for brain stimulation treatment and contributed to the optimization of patient-specific brain stimulation protocols.

A systematic review of high-frequency transcranial magnetic stimulation on motor cortex areas as a migraine preventive treatment

Background:

The results of high-frequency repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral prefrontal cortex for migraine have been inconsistent. However, high-frequency rTMS over the motor cortex is a treatment that may be effective in relieving symptoms of migraine with a low risk of side effects.

Methods:

A systematic review of high-frequency rTMS over the brain motor cortex areas in human participants was conducted to assess efficacy in treating migraine. Articles that were not looking at migraine patients, stimulation over the left motor cortex, or were not in English were excluded. Nine articles representing eight experiments using high-frequency rTMS over the motor cortex areas for migraine in human participants were extracted from the databases of PubMed, PsycINFO, MedLine, CINAHL, and BioMed Central.

Results:

Two-hundred and seven of 213 patients completed treatment throughout all the studies examined. High-frequency rTMS over the motor cortex areas for migraine improved migraine frequency in seven of eight studies. Two of the eight studies were randomized controlled trials at low risk for biases and found high-frequency rTMS over the motor cortex areas effective in improving migraine frequency and severity. Other details of treatment prescription and symptoms were also examined.

Conclusion:

High-frequency rTMS over the motor cortex areas for migraine demonstrated efficacy as a migraine treatment, had minimal side effects, and should be further investigated.

Brain oscillation-synchronized stimulation of the left dorsolateral prefrontal cortex in depression using real-time EEG-triggered TMS

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC) is an effective treatment for major depressive disorder (MDD), but response rates are low and effect sizes small. Synchronizing TMS pulses with instantaneous brain oscillations can reduce variability and increase efficacy of TMS-induced plasticity.

OBJECTIVE

To study whether brain oscillation-synchronized rTMS is feasible, safe and has neuromodulatory effects when targeting the DLPFC of patients with MDD.

METHODS

Using real-time EEG-triggered TMS we conducted a pseudo-randomized controlled single-session crossover trial of brain oscillation-synchronized rTMS of left DLPFC in 17 adult patients with antidepressant-resistant MDD. Stimulation conditions in separate sessions were: (1) rTMS triggered at the negative EEG peak of instantaneous alpha oscillations (alpha-synchronized rTMS), (2) a variation of intermittent theta-burst stimulation (modified iTBS), and (3) a random alpha phase control condition.

RESULTS

Triggering TMS at the negative peak of instantaneous alpha oscillations by real-time analysis of the electrode F5 EEG signal was successful in 15 subjects. Two subjects reported mild transient discomfort at the site of stimulation during stimulation; no serious adverse events were reported. Alpha-synchronized rTMS, but not modified iTBS or the random alpha phase control condition, reduced resting-state alpha activity in left DLPFC and increased TMS-induced beta oscillations over frontocentral channels.

CONCLUSIONS

Alpha-synchronized rTMS of left DLPFC is feasible, safe and has specific single-session neuromodulatory effects in patients with antidepressant-resistant MDD. Future studies need to further elucidate the mechanisms, optimize the parameters and investigate the therapeutic potential and efficacy of brain oscillation-synchronized rTMS in MDD.

Does rTMS reduce depressive symptoms in young people who have not responded to antidepressants?

AIM

Depression is common in young people, and there is a need for safe, effective treatments. This study examined the efficacy of repetitive transcranial magnetic stimulation in a sample of young people aged 17 to 25 years.

METHODS

This retrospective study included 15 people aged 17 to 25 years referred by their private psychiatrists affiliated with Ramsay Health Care, South Australia Mental Health Services. All patients met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for treatment-resistant Major Depressive Disorder. Eleven patients received right unilateral treatment and four patients received bilateral treatment. Patients were assessed at baseline and after treatment.

RESULTS

There was a significant improvement on the Hamilton Rating Scale for Depression (t(14) = 4.71, P < 0.0001); Montgomery-Åsperg Depression Rating Scale (t(14) = 3.96, P < 0.01) and the Zung Self-Rating Depression Scale (t(14) = 4.13, P < 0.01). There was no difference in response by gender or age. The response rates in these young people did not differ significantly from those of adults aged 25 to 82 years.

CONCLUSION

This open label, naturalistic study suggests that repetitive transcranial magnetic stimulation is an effective treatment in young adults who have treatment-resistant depression. Randomized sham-controlled studies are needed to further investigate the efficacy of this treatment in this age group.

An Update on Repetitive Transcranial Magnetic Stimulation for the Treatment of Major Depressive Disorder

Repetitive transcranial magnetic stimulation (rTMS) has emerged as an evidenced-based treatment for major depression that does not respond to standard first-line therapies. The majority of data support the use of high-frequency (10 Hz) treatment delivered to the left dorsolateral prefrontal cortex. Intermittent theta burst stimulation is a new emerging treatment that reduces the time required to deliver treatment and can increase capacity and access to this treatment. This review will comprehensively cover recent advancements in the field of rTMS for depression, including stimulation parameters and targets aimed at enhancing outcomes. In addition, efforts to use modern neuroscience tools to personalize this treatment and optimize outcomes will be reviewed.

Effects of Left Versus Right Dorsolateral Prefrontal Cortex Repetitive Transcranial Magnetic Stimulation on Affective Flexibility in Healthy Women: A Pilot Study

OBJECTIVE

To determine the antidepressant mechanism of action for repetitive transcranial magnetic stimulation (rTMS) to the left dorsolateral prefrontal cortex (DLPFC) in healthy women. Our primary hypothesis was that a single session of left DLPFC rTMS, compared with a session of right DLPFC rTMS, would result in better (reduced) negative nonaffective switch costs in healthy women.

BACKGROUND

The antidepressant mechanism of action for rTMS is not clear. It is possible that rTMS to the DLPFC improves emotion regulation, which could be a part of its antidepressant mechanism.

METHODS

Twenty-five healthy women were randomized to receive left high-frequency (HF) rTMS versus right HF rTMS in one session and then contralateral stimulation during a second session. Emotion regulation was assessed via switch costs for reappraisal of negatively valenced information on an affective flexibility task.

RESULTS

For negative nonaffective switch costs, the interaction effect in the two-way ANOVA was not significant (F1,19=3.053, P=0.097). Given that left HF rTMS is the approved treatment for depression, post hoc t tests were completed with particular interest in the left-side findings. These tests confirmed that negative nonaffective switch costs significantly improved immediately after left rTMS (t1,19=2.664, P=0.015) but not right rTMS.

CONCLUSIONS

These findings suggest that left DLPFC HF rTMS may lead to antidepressant effects by improving the regulation of emotion.

Unilateral and bilateral repetitive transcranial magnetic stimulation for treatment-resistant depression: a meta-analysis of randomized controlled trials over 2 decades

BACKGROUND

Approximately 35% of people with depression do not respond to 2 courses of antidepressant medications of adequate dosage, and treatment-resistant depression (TRD) is still a major clinical concern with a great impact on patients, their families, society and the health system. The present meta-analysis evaluates antidepressant efficacy of unilateral and bilateral repetitive transcranial magnetic stimulation (rTMS) in patients with unipolar TRD.

METHODS

We searched for randomized controlled trials that compared rTMS with sham treatment and were published by Apr. 3, 2017. The primary outcome was improvement in depression scores measured using the Hamilton Rating Scale for Depression. The secondary outcomes were remission and response rates. Two independent review authors screened the studies and extracted the data.

RESULTS

Twenty-three studies met the inclusion criteria. Meta-analysis of the depression scores showed a weighted mean difference (WMD) of 3.36 (95% confidence interval [CI] 1.85–4.88) between unilateral rTMS and sham treatment. Stratified data showed that the effect was relatively higher when rTMS was used as an add-on to antidepressant medications (WMD 3.64, 95% CI 1.52–5.76) than when it was used as a stand-alone treatment (WMD 2.47, 95% CI 0.90–4.05). The WMD between bilateral rTMS and sham was 2.67 (95% CI 0.83–4.51), and all studies that contributed to this outcome used rTMS while participants were taking antidepressant medications. The pooled remission and response rates for unilateral rTMS versus sham treatment were 16.0% and 25.1% for rTMS and 5.7% and 11.0% for sham treatment, respectively. The pooled remission and response rates for bilateral rTMS versus sham treatment were 16.6% and 25.4% for rTMS and 2.0% and 6.8% for sham treatment, respectively.

CONCLUSION

This study suggests that rTMS has moderate antidepressant effects and appears to be promising in the short-term treatment of patients with unipolar TRD.

A double-blind pilot dosing study of low field magnetic stimulation (LFMS) for treatment-resistant depression (TRD)

BACKGROUND

Low field magnetic stimulation is a potentially rapid-acting treatment for depression with mood-enhancing effects in as little as one 20-min session. The most convincing data for LFMS has come from treating bipolar depression. We examined whether LFMS also has rapid mood-enhancing effects in treatment-resistant major depressive disorder, and whether these effects are dose-dependent.

OBJECTIVE/HYPOTHESIS

We hypothesized that a single 20-min session of LFMS would reduce depressive symptom severity and that the magnitude of this change would be greater after three 20-min sessions than after a single 20-min session.

METHODS

In a double-blind randomized controlled trial, 30 participants (age 21-65) with treatment-resistant depression were randomized to three 20-min active or sham LFMS treatments with 48 h between treatments. Response was assessed immediately following LFMS treatment using the 6-item Hamilton Depression Rating Scale (HAMD-6), the Positive and Negative Affect Scale (PANAS) and the Visual Analog Scale.

RESULTS

Following the 3rd session of LFMS, the effect of LFMS on VAS and HAMD-6 was superior to sham (F (1, 24) = 7.45, p = 0.03, Bonferroni-Holm corrected; F (1, 22) = 6.92, p = 0.03, Bonferroni-Holm corrected, respectively). There were no differences between sham and LFMS following the initial or second session with the effect not becoming significant until after the third session.

CONCLUSIONS

Three 20-min LFMS sessions were required for active LFMS to have a mood-enhancing effect for individuals with treatment-resistant depression. As this effect may be transient, future work should address dosing schedules of longer treatment courses as well as biomarker-based targeting of LFMS to optimize patient selection and treatment outcomes.

Attentional bias modification reduces clinical depression and enhances attention toward happiness

Difficulty in clinical antidepressant treatment leads to the pursuit of alternative treatments, such as cognitive-behavior therapy (CBT). CBT combined with regular antidepressants have indicated an optimal therapeutic effect in clinic. Attentional bias is important in the occurrence and remission of depression, however, few studies have explored the effect of attentional bias modification (ABM) on depression, and inconsistent results have been obtained due to the heterogeneity in the targeted populations, training tasks, strategies, and materials. Hence, the current study aimed to explore the therapeutic effect of ABM on depression in clinical depression. Study I was designed to explore the optimal training methods regarding task (dot-probe vs. cue-target), material (faces vs. self-referent words), and strategy (mixed ABM toward positive and away from negative stimuli vs. positive ABM toward positive stimuli) in unselected undergraduates once daily for 10 days (N = 309). Study II was carried out to observe the effect of 10 days ABM toward positive and away from negative faces (based on Study I) on clinical depression (N = 32). Depression level was assessed via a self-reporting questionnaire and a structured interview, while attentional bias was tested by cue-target task and attention to positive and negative inventory (APNI). In unselected undergraduates (Study I), two strategies significantly reduced the self-reporting depression scores: mixed ABM toward positive stimuli and away from negative stimuli with emotional faces, and positive ABM toward positive materials only with self-referent words. In patients with major depressive disorder (MDD) (Study II), the mixed ABM with emotional faces resulted in enhanced attentional bias toward happy materials in the cue-target task and APNI, which predicted a delayed depression reduction in clinical depression at the one-month follow-up investigation. Our finding confirms the literature and broadens the knowledge with the evidence of the optimal therapeutic effect of ABM combined with regular antidepressants in clinical depression. The findings that a quick enhancement in positive attentional bias, predicting a later therapeutic effect on clinical depression reduction, indicate a potential mechanism that could underlie the therapeutic process of ABM in depression. The findings that two training strategies are effective in depression reduction suggest that different strategies should be utilized to treat different types of depression. This study offers a potential way to cure depression and could be further practiced in clinic.

Antidepressant Effects of Repetitive Transcranial Magnetic Stimulation Over Prefrontal Cortex of Parkinson's Disease Patients With Depression: A Meta-Analysis

Objective: The purpose of this meta-analysis was to investigate the antidepressant effects of repetitive transcranial magnetic stimulation (rTMS) over the prefrontal cortex (PFC) of patients with Parkinson's disease (PD) and to determine the optimal rTMS parameters, such as the intensity, frequency and the delivered pattern of rTMS stimulation. Methods: EMBASE, PubMed, Web of Science, MEDLINE, and Cochrane data bases were researched for papers published before March 12, 2018. Studies investigating the anti-depression effects of rTMS over PFC in patients with PD were considered. The main outcomes of pre- and post-rTMS treatment as well as score changes were all extracted. The mean effect size was estimated by calculating the standardized mean difference (SMD) with 95% confidence interval (CI) by using fixed or random effect models as appropriate. Results: Nine studies containing 137 PD patients with depression were included. The pooled results showed significant pre-post anti-depressive effects of rTMS over PFC in PD patients with depression (SMD = -0.80, P < 0.00001). The subgroup analyses of stimulation intensity, frequencies, and models also revealed significant effects (Intensities: 90% RMT: SMD = -1.16, P = 0.0006; >100% RMT: SMD = -0.82, P < 0.0001. Frequencies: < 1.0 Hz: SMD = -0.83, P = 0.03; 5.0 Hz: SMD = -1.10, P < 0.0001; ≥10.0 Hz: SMD = -0.55, P = 0.02. Models: Continuous: SMD = -0.79, P < 0.0001; Discontinuous: SMD = -0.84, P = 0.02). But the results of the studies with place-controlled designs were not significant (Overall: SMD = -0.27, P = 0.54. Intensities: 90% RMT: SMD = 0.27, P = 0.68; 100% RMT: SMD = -0.32, P = 0.33. Frequencies: 5.0 Hz: SMD = -0.87, P = 0.10; ≥10.0 Hz: SMD = 0.27, P = 0.66. Models: Continuous: SMD = -0.28, P = 0.68; Discontinuous: SMD = -0.32, P = 0.33). The greater effect sizes of rTMS with 90% RMT, 5.0 Hz in discontinuous days can be observed rather than the other parameters in both kinds of analyses across study design. Conclusions: rTMS may have a significant positive pre-post anti-depressive effect over PFC on patients with depression, especially by using 5.0 Hz frequency with 90% RMT intensity in discontinuous days, which may produce better effects than other parameters. The real effect, though, was not different from that of the placebo. Future studies with larger sample sizes and high-quality studies are needed to further corroborate our results and to identify the optimal rTMS protocols.

Durability of antidepressant response to repetitive transcranial magnetic stimulation: Systematic review and meta-analysis

BACKGROUND

The therapeutic options for treatment-resistant depression (TRD) encompass a range of neuromodulatory techniques, including repetitive transcranial magnetic stimulation (rTMS). While rTMS is safe and has documented short-term efficacy, durability of antidepressant effects is poorly established.

OBJECTIVE

Assess existing evidence regarding durability of rTMS-induced antidepressant response.

METHODS

We performed a systematic review of studies reporting antidepressant outcome measures collected three or more months after the end of an induction course of rTMS for depression. Among responders to the induction course, we used a meta-analytic approach to assess response rates at 3 (m3), 6 (m6) or 12 (m12) months after induction, and studied predictors of responder rates using meta-regression.

RESULTS

Nineteen studies published between 2002 and 2018 were included. Eighteen were eligible for analysis at m3 (732 patients) and m6 (695 patients) and 9 at m12 (247 patients). Among initial responders, 66.5% sustained response at m3 (95% CI = 57.1-74.8%, I² = 27.6%), 52.9% at m6 (95% CI = 40.3-65%, I² = 0%), and 46.3% at m12 (95% CI = 32.6-60.7%, I² = 0%), in the absence of any major bias. Random-effects meta-regressions further demonstrated that a higher proportion of women, as well as receipt of maintenance treatment, predicted higher responder rates at specific time-points.

CONCLUSIONS

rTMS is a durable treatment for depression, with sustained responder rates of 50% up to 1 year after a successful induction course of treatment. Maintenance treatment may enhance the durability of the antidepressant effects of rTMS, and should be considered in clinical practice, as well as systematically explored in future clinical trials.

Use of a Double-Cone Coil in Transcranial Magnetic Stimulation for Depression Treatment

INTRODUCTION

Approximately 15% of all people will experience a depressive episode throughout their lives, and by 2020, depression will be the second largest cause of disability around the world. Transcranial magnetic stimulation (TMS) has been shown to be an effective option for treating this condition. Devices such as the double-cone coil may bring new insights regarding depression treatment.

METHODS

A literature search was performed on PubMed, ScienceDirect, Cochrane, LILACS, and Google Scholar by applying the descriptors "depression" AND "transcranial magnetic stimulation" AND "double cone-coil."

RESULTS

Six studies were considered eligible (three clinical trials, two case series, and one isolated case report). All of them described treatments with transcranial magnetic stimulation by double-cone coil (DC-TMS) at 10 Hz over the dorsomedial prefrontal cortex, achieving response and remission rates of 40-52.4% and 34.7-47.6%, respectively. Two clinical trials investigated both intermittent theta-burst stimulation and 10 Hz TMS, suggesting a slight advantage of the latter. They also found no additional gains by combining both techniques.

CONCLUSION

Despite the small number of controlled clinical trials and the small sample sizes, which limit the generalization of the obtained results, the collected data provide an optimistic perspective on the effectiveness of using DC-TMS for depression treatment.

Remission rate of transcranial magnetic stimulation compared with electroconvulsive therapy: a case-control study

PURPOSE

To compare the rate of remission, rate of response, change in depressive symptoms, and adverse effects between repetitive transcranial magnetic stimulation (rTMS) and electroconvulsive therapy (ECT).

MATERIALS AND METHODS

In this retrospective case-control study, 35 patients treated for depression with rTMS (left dorsolateral prefrontal cortex, 90% observed motor threshold, 10 Hz, 2000 pulses/session, 15 sessions) at Örebro University Hospital, Sweden (cases), were compared with a matched group of 35 patients treated for depression with ECT (controls). Data on controls were obtained from the Swedish National Quality Register for ECT (Q-ECT). Severity of depression was evaluated using the Montgomery-Åsberg Depression rating scale (MADRS).

RESULTS

Remission rate was 26% for cases and 43% for controls (p = .3). Response rate was 40% for cases and 51% for controls (p = .63). The median decrease in MADRS was 11 (IQR 3-19) vs. 17 (IQR 6-27; p = .10) for rTMS and ECT, respectively. There was no statistically significant difference in any measure of treatment effect between rTMS and ECT. More than half of the patients of the rTMS group experienced scalp discomfort and 11% of the ECT group had memory disturbances.

CONCLUSIONS

All measures of therapeutic efficacy were numerically inferior in the rTMS group compared to the ECT group. The differences were not statistically significant, probably because the sample size was small. More studies are required to find the optimal place for rTMS within the Swedish health care system. Such studies could be facilitated by inclusion of rTMS in the Q-ECT.

Complexity Analysis of EEG Data in Persons With Depression Subjected to Transcranial Magnetic Stimulation

Aim: The aim of this work was to study the neurophysiological effect of repetitive transcranial magnetic stimulation (rTMS) applied to the left dorsolateral prefrontal cortex (DLPFC) in 8 patients with major depression disorder (MDD) and 10 patients with bipolar disorder (BP), considering separately responders and non-responders to rTMS therapy in each of both groups. Methods: The Higuchi's Fractal Dimension (FD) was analyzed from 64-channels EEG signals in five physiological frequency bands and every channel separately. Changes of FD were analyzed before and after 1st, 10th, and 20th session of rTMS. Results: Some differences in response to the rTMS therapy was found across individual groups. In MDD responders, FD decreased in all bands after longer stimulation (20th session). Whereas, in BP non-responders, FD decreased after 1st session in all bands as well as after 10th session in lower frequencies (delta and theta). In MDD non-responders and BP responders FD increased at the beginning of the therapy (1st and 10th session, respectively), but the final FD value did not changed in comparison to the initial FD value, except the FD decrease for theta band in BP responders. Comparison between groups showed a higher FD in MDD responders than in MDD non-responders in every band before as well as after stimulation. In contrast to MDD patients, FD was lower in BP responders than in BP non-responders in higher frequency bands (alpha, beta, and gamma) in both conditions as well as in lower frequency bands (delta and theta) after stimulation. Comparing both groups of responders, FD was lower in MDD than in BP in every band, except alpha. In case of non-responders, FD was higher in BP than in MDD in all bands in both conditions. Conclusion: The results showed that FD may be useful marker for evaluation of the rTMS effectiveness and the therapy progress as well as for group differentiation between MDD and BP or between responders and non-responders. The changes of FD under the influence of rTMS allow to unambiguously conclude whether the effect of stimulation is positive or negative as well as allow to evaluate an optimal time of rTMS.