5Hz Repetitive transcranial magnetic stimulation to left prefrontal cortex for major depression

Accelerated TMS - moving quickly into the future of depression treatment

Accelerated TMS is an emerging application of Transcranial Magnetic Stimulation (TMS) aimed to reduce treatment length and improve response time. Extant literature generally shows similar efficacy and safety profiles compared to the FDA-cleared protocols for TMS to treat major depressive disorder (MDD), yet accelerated TMS research remains at a very early stage in development. The few applied protocols have not been standardized and vary significantly across a set of core elements. In this review, we consider nine elements that include treatment parameters (i.e., frequency and inter-stimulation interval), cumulative exposure (i.e., number of treatment days, sessions per day, and pulses per session), individualized parameters (i.e., treatment target and dose), and brain state (i.e., context and concurrent treatments). Precisely which of these elements is critical and what parameters are most optimal for the treatment of MDD remains unclear. Other important considerations for accelerated TMS include durability of effect, safety profiles as doses increase over time, the possibility and advantage of individualized functional neuronavigation, use of biological readouts, and accessibility for patients most in need of the treatment. Overall, accelerated TMS appears to hold promise to reduce treatment time and achieve rapid reduction in depressive symptoms, but at this time significant work remains to be done. Rigorous clinical trials combining clinical outcomes and neuroscientific measures such as electroencephalogram, magnetic resonance imaging and e-field modeling are needed to define the future of accelerated TMS for MDD.

Repetitive Transcranial Magnetic Stimulation Reduces Depressive-like Behaviors, Modifies Dendritic Plasticity, and Generates Global Epigenetic Changes in the Frontal Cortex and Hippocampus in a Rodent Model of Chronic Stress

Depression is the most common affective disorder worldwide, accounting for 4.4% of the global population, a figure that could increase in the coming decades. In depression, there exists a reduction in the availability of dendritic spines in the frontal cortex (FC) and hippocampus (Hp). In addition, histone modification and DNA methylation are also dysregulated epigenetic mechanisms in depression. Repetitive transcranial magnetic stimulation (rTMS) is a technique that is used to treat depression. However, the epigenetic mechanisms of its therapeutic effect are still not known. Therefore, in this study, we evaluated the antidepressant effect of 5 Hz rTMS and examined its effect on dendritic remodeling, immunoreactivity of synapse proteins, histone modification, and DNA methylation in the FC and Hp in a model of chronic mild stress. Our data indicated that stress generated depressive-like behaviors and that rTMS reverses this effect, romotes the formation of dendritic spines, and favors the presynaptic connection in the FC and DG (dentate gyrus), in addition to increasing histone H3 trimethylation and DNA methylation. These results suggest that the antidepressant effect of rTMS is associated with dendritic remodeling, which is probably regulated by epigenetic mechanisms. These data are a first approximation of the impact of rTMS at the epigenetic level in the context of depression. Therefore, it is necessary to analyze in future studies as to which genes are regulated by these mechanisms, and how they are associated with the neuroplastic modifications promoted by rTMS.

Repetitive transcranial magnetic stimulation and fluoxetine reverse depressive-like behavior but with differential effects on Olig2-positive cells in chronically stressed mice

Depression is a mood disorder coursing with several behavioral, cellular, and neurochemical alterations. The negative impact of chronic stress may precipitate this neuropsychiatric disorder. Interestingly, downregulation of oligodendrocyte-related genes, abnormal myelin structure, and reduced numbers and density of oligodendrocytes in the limbic system have been identified in patients diagnosed with depression, but also in rodents exposed to chronic mild stress (CMS). Several reports have emphasized the importance of pharmacological or stimulation-related strategies in influencing oligodendrocytes in the hippocampal neurogenic niche. Repetitive transcranial magnetic stimulation (rTMS) has gained attention as an intervention to revert depression. Here, we hypothesized that 5 Hz (Hz) of rTMS or Fluoxetine (Flx) would revert depressive-like behaviors by influencing oligodendrocytes and revert neurogenic alterations caused by CMS in female Swiss Webster mice. Our results showed that 5 Hz rTMS or Flx revert depressive-like behavior. Only rTMS influenced oligodendrocytes by increasing the number of Olig2-positive cells in the hilus of the dentate gyrus and the prefrontal cortex. However, both strategies exerted effects on some events of the hippocampal neurogenic processes, such as cell proliferation (Ki67-positive cells), survival (CldU-positive cells), and intermediate stages (doublecortin-positive cells) along the dorsal-ventral axis of this region. Interestingly, the combination of rTMS-Flx exerted antidepressant-like effects, but the increased number of Olig2-positive cells observed in mice treated only with rTMS was canceled. However, rTMS-Flx exerted a synergistic effect by increasing the number of Ki67-positive cells. It also increased the number of CldU- and doublecortin-positive cells in the dentate gyrus. Our results demonstrate that 5 Hz rTMS has beneficial effects, as it reverted depressive-like behavior by increasing the number of Olig2-positive cells and reverting the decrement in hippocampal neurogenesis in CMS-exposed mice. Nevertheless, the effects of rTMS on other glial cells require further investigation.

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.

Impact of response shift effects in the assessment of self-reported depression during treatment: Insights from a rTMS versus Venlafaxine randomized controlled trial

PURPOSE

Patient-Reported Outcomes are essential to properly assess treatment effectiveness in randomized clinical trial (RCT) for Major Depressive Disorder (MDD). MDD self-assessment may vary over time depending on change in the meaning of patients' self-evaluation of depression, i.e. Response Shift (RS). Our aim was to investigate RS and its impact on different depression domains in a clinical trial comparing rTMS versus Venlafaxine.

METHODS

The occurrence and type of RS was determined using Structural Equation Modeling applied to change over time in 3 domains (Sad Mood, Performance Impairment, Negative Self-Reference) of the short-form Beck Depression Inventory (BDI-13) in a secondary analysis of a RCT on 170 patients with MDD treated by rTMS, venlafaxine or both.

RESULTS

RS was evidenced in the venlafaxine group in the Negative Self-Reference and Sad Mood domains.

CONCLUSION

RS effects differed between treatment arms in self-reported depression domains in patients with MDD. Ignoring RS would have led to a slight underestimation of depression improvement, depending on treatment group. Further investigations of RS and advancing new methods are needed to better inform decision making based on Patient-Reported Outcomes.

Transcranial Magnetic Stimulation for Posttraumatic Stress Disorder and Major Depression: Comparing Commonly Used Clinical Protocols

Transcranial magnetic stimulation (TMS) is increasingly being used to treat posttraumatic stress disorder (PTSD) comorbid with major depressive disorder (MDD). Yet, identifying the most effective stimulation parameters remains an active area of research. We recently reported on the use of 5 Hz TMS to reduce PTSD and MDD symptoms. A recently developed form of TMS, intermittent theta burst stimulation (iTBS), appears noninferior for treating MDD. Because iTBS can be delivered in a fraction of the time, it provides significant logistical advantages; however, evaluations of whether iTBS provides comparable PTSD and MDD symptom reductions are lacking. We performed a retrospective chart review comparing clinical outcomes in veterans with PTSD and MDD who received iTBS (n = 10) with a matched cohort that received 5-Hz TMS (n = 10). Symptoms were evaluated using self-reported rating scales at baseline and every five treatments for up to 30 sessions. Both protocols were safe and reduced symptoms, ps < .001, but veterans who received iTBS reported poorer outcomes. These results were observed using mixed-model analyses, Group x Time interaction: p = .011, and effect sizes, where 5 Hz TMS demonstrated superior PTSD and MDD symptom improvement, ds = 1.81 and 1.51, respectively, versus iTBS, ds = 0.63 and 0.88, respectively. Data from prior controlled trials of iTBS, with increased stimulation exposure, have appeared to provide comparable clinical outcomes compared with 5 Hz TMS. Prospective and controlled comparisons are required; however, the present findings provide important information for clinicians using TMS to treat these commonly comorbid disorders.

Psychiatric Applications of Repetitive Transcranial Magnetic Stimulation

Transcranial magnetic stimulation (TMS) is an increasingly popular noninvasive brain stimulation modality. In TMS, a pulsed magnetic field is used to noninvasively stimulate a targeted brain region. Repeated stimulation produces lasting changes in brain activity via mechanisms of synaptic plasticity similar to long-term potentiation. Local application of TMS alters activity in distant, functionally connected brain regions, indicating that TMS modulates activity of cortical networks. TMS has been approved by the U.S. Food and Drug Administration for the treatment of major depressive disorder, obsessive-compulsive disorder, and smoking cessation, and a growing evidence base supports its efficacy in the treatment of other neuropsychiatric conditions. TMS is rapidly becoming part of the standard of care for treatment-resistant depression, where it yields response rates of 40%-60%. TMS is generally safe and well tolerated; its most serious risk is seizure, which occurs very rarely. This review aims to familiarize practicing psychiatrists with basic principles of TMS, including target localization, commonly used treatment protocols and their outcomes, and safety and tolerability. Practical considerations, including evaluation and monitoring of patients undergoing TMS, device selection, treatment setting, and insurance reimbursement, are also reviewed.

Effect of transcranial magnetic stimulation as an enhancer of cognitive stimulation sessions on mild cognitive impairment: Preliminary results

Mild cognitive impairment (MCI) is a state between normal cognition and dementia. Currently, there is little evidence of repetitive Transcranial Magnetic Stimulation (rTMS) as an enhancing tool for Cognitive Stimulation (CS) on MCI. The importance of this study consists in its assessment of the enhancing effect of rTMS on CS in 22 MCI patients randomized and divided into two group: active (AG) and sham (SG). Diagnoses and assessments were determined during 30 sessions over a 10-week period by Montreal Cognitive Assessment (MoCA) and Neuropsí test. Results were statistically significant in the intergroup analysis with MoCA and intragroup only for AG.

Safety Review for Clinical Application of Repetitive Transcranial Magnetic Stimulation

Studies using repetitive transcranial magnetic stimulation (rTMS) in healthy individuals and those with neuropsychiatric diseases have rapidly increased since the 1990s, due to the potential of rTMS to modulate the cortical excitability in the brain depending on the stimulation parameters; therefore, the safety considerations for rTMS use are expected to become more important. Wassermann published the first safety guidelines for rTMS from the consensus conference held in 1996, and Rossi and colleague then published the second safety guidelines from the multidisciplinary consensus meeting held in Siena, Italy in 2008, on behalf of the International Federation of Clinical Neurophysiology. More than 10 years after the second guidelines, the updated third safety guidelines were recently published in 2021. The general safety guidelines for conventional rTMS have not substantially changed. Because the most frequently used rTMS protocol is conventional (low- and high-frequency) rTMS in research and clinical settings, we focus on reviewing safety issues when applying conventional rTMS with a focal cortical stimulation coil. The following issues will be covered: 1) possible adverse events induced by rTMS; 2) checklists to screen for any precautions and risks before rTMS; 3) safety considerations for dosing conventional rTMS; and 4) safety considerations for using rTMS in stroke and traumatic brain injury.

Safety and recommendations for TMS use in healthy subjects and patient populations, with updates on training, ethical and regulatory issues: Expert Guidelines

This article is based on a consensus conference, promoted and supported by the International Federation of Clinical Neurophysiology (IFCN), which took place in Siena (Italy) in October 2018. The meeting intended to update the ten-year-old safety guidelines for the application of transcranial magnetic stimulation (TMS) in research and clinical settings (Rossi et al., 2009). Therefore, only emerging and new issues are covered in detail, leaving still valid the 2009 recommendations regarding the description of conventional or patterned TMS protocols, the screening of subjects/patients, the need of neurophysiological monitoring for new protocols, the utilization of reference thresholds of stimulation, the managing of seizures and the list of minor side effects. New issues discussed in detail from the meeting up to April 2020 are safety issues of recently developed stimulation devices and pulse configurations; duties and responsibility of device makers; novel scenarios of TMS applications such as in the neuroimaging context or imaging-guided and robot-guided TMS; TMS interleaved with transcranial electrical stimulation; safety during paired associative stimulation interventions; and risks of using TMS to induce therapeutic seizures (magnetic seizure therapy). An update on the possible induction of seizures, theoretically the most serious risk of TMS, is provided. It has become apparent that such a risk is low, even in patients taking drugs acting on the central nervous system, at least with the use of traditional stimulation parameters and focal coils for which large data sets are available. Finally, new operational guidelines are provided for safety in planning future trials based on traditional and patterned TMS protocols, as well as a summary of the minimal training requirements for operators, and a note on ethics of neuroenhancement.

Left Dorsolateral Prefrontal Cortex Glx/tCr Predicts Efficacy of High Frequency 4- to 6-Week rTMS Treatment and Is Associated With Symptom Improvement in Adults With Major Depressive Disorder: Findings From a Pilot Study

About 20-40% of estimated 121 million patients with major depressive disorder (MDD) are not adequately responsive to medication treatment. Repetitive transcranial magnetic stimulation (rTMS), a non-invasive, non-convulsive neuromodulation/neurostimulation method, has gained popularity in treatment of MDD. Because of the high cost involved in rTMS therapy, ability to predict the therapy effectiveness is both clinically and cost wise significant. This study seeks an imaging biomarker to predict efficacy of rTMS treatment using a standard high frequency 10-Hz 4- to 6-week protocol in adult population. Given the significance of excitatory and inhibitory neurotransmitters glutamate (Glu) and gamma aminobutyric acid (GABA) in the pathophysiology of MDD, and the involvement of the site of rTMS application, left dorsolateral prefrontal cortex (lDLPFC), in MDD, we explored lDLPFC Glx (Glu + glutamine) and GABA levels, measured by single voxel magnetic resonance spectroscopy (MRS) with total creatine (tCr; sum of creatine and phosphocreatine) as reference, as possible biomarkers of rTMS response prediction. Mescher-Garwood point-resolved spectroscopy (MEGA-PRESS) MRS data from 7 patients (40-74 y) were used in the study; 6 of these patients were scanned before and after 6 weeks of rTMS therapy. Findings from this study show inverse correlation between pretreatment lDLPFC Glx/tCr and (i) posttreatment depression score and (ii) change in depression score, suggesting higher Glx/tCr as a predictor of treatment efficacy. In addition association was observed between changes in depression scores and changes in Glx/tCr ratio. The preliminary findings did not show any such association between GABA/tCr and depression score.

Magnetic brain stimulation using iron oxide nanoparticle-mediated selective treatment of the left prelimbic cortex as a novel strategy to rapidly improve depressive-like symptoms in mice

Magnetic brain stimulation has greatly contributed to the advancement of neuroscience. However, challenges remain in the power of penetration and precision of magnetic stimulation, especially in small animals. Here, a novel combined magnetic stimulation system (c-MSS) was established for brain stimulation in mice. The c-MSS uses a mild magnetic pulse sequence and injection of superparamagnetic iron oxide (SPIO) nanodrugs to elevate local cortical susceptibility. After imaging of the SPIO nanoparticles in the left prelimbic (PrL) cortex in mice, we determined their safety and physical characteristics. Depressive-like behavior was established in mice using a chronic unpredictable mild stress (CUMS) model. SPIO nanodrugs were then delivered precisely to the left PrL cortex using in situ injection. A 0.1 T magnetic field (adjustable frequency) was used for magnetic stimulation (5 min/session, two sessions daily). Biomarkers representing therapeutic effects were measured before and after c-MSS intervention. Results showed that c-MSS rapidly improved depressive-like symptoms in CUMS mice after stimulation with a 10 Hz field for 5 d, combined with increased brain-derived neurotrophic factor (BDNF) and inactivation of hypothalamic-pituitary-adrenal (HPA) axis function, which enhanced neuronal activity due to SPIO nanoparticle-mediated effects. The c-MSS was safe and effective, representing a novel approach in the selective stimulation of arbitrary cortical targets in small animals, playing a bioelectric role in neural circuit regulation, including antidepressant effects in CUMS mice. This expands the potential applications of magnetic stimulation and progresses brain research towards clinical application.

Transcranial magnetic stimulation to reduce suicidality - A review and naturalistic outcomes

Although there is growing interest in the use of repetitive Transcranial Magnetic Stimulation (TMS) as a treatment for suicidality, efficacy data in this area, and knowledge of potential treatment mechanisms, remains limited. The first objective of this study was to systematically review clinical trial data examining the effectiveness of TMS as a treatment for suicidal ideation. Our secondary objective was to investigate the extent to which changes in suicidality are independent of improvements in depression in a clinical sample of veterans who received TMS treatment. In Study 1, we searched the Pubmed and biRxiv databases from inception until July 2019 to identify studies that examined the efficacy of TMS for suicidal thoughts and/or behaviors. Data regarding sample characteristics, treatment parameters, and results were synthesized from six randomized controlled trials and five unblinded trials (total n = 593). Our systematic review indicated that while TMS was consistently associated with reduced depression, its impact on suicidality is unclear. Interpretation of results related to suicidality were complicated by study design elements and modest sample sizes. In Study 2, we conducted a retrospective analysis of 43 patients who received care for depression in a neuromodulation clinic at a Veteran's Affairs hospital. Results found significant decreases in suicidal ideation, and depressive symptom change did not always account for improvements in ideation. Taken together, our literature review and clinic study indicate preliminary promise of TMS for suicide, and underscore the need for more fine-grained, suicide-specific TMS research.

Effect of Previous Electroconvulsive Therapy on Subsequent Response to Transcranial Magnetic Stimulation for Major Depressive Disorder

OBJECTIVES

Patients with major depressive disorder (MDD) who received electroconvulsive therapy (ECT) often seek transcranial magnetic stimulation (TMS) therapy as a less invasive treatment option. How prior history of ECT and its responsiveness may affect TMS treatment outcomes for MDD is unclear. We aim to contribute evidence to this important clinical question.

MATERIALS AND METHODS

Retrospective naturalistic TMS treatment data from n = 257 MDD patients. Three sets of analyses were conducted: History of past exposure to ECT (n = 71, "+ECT" vs. n = 186 ECT-naïve, "-ECT") was examined as a potential predictor of TMS outcomes (measured by two self-report scales); A subset of n = 38 +ECT patients with adequate ECT trials in current depression episode were compared with -ECT patients blindly matched on clinical variables associated with TMS outcomes; for a subset with available data, TMS outcomes were explored in relation to positive/negative response to prior ECT.

RESULTS

Compared to -ECT, +ECT patients more likely had past psychiatric hospitalizations (p < 0.01) and were more severely depressed at baseline (p = 0.07). Response (p = 0.07) and remission (p = 0.02) rates were higher in -ECT than +ECT groups on one scale. However, comparison between the subsets (n = 38 each) matched on confounding factors did not find history of ECT to be a significant independent predictor of TMS outcomes. Differential responsiveness to ECT and ECT treatment characteristics did not significantly impact TMS outcomes.

CONCLUSIONS

Although limited by the retrospective nature of this analysis, the results suggest that history of the past ECT, regardless of responsiveness to ECT, may not independently portend differential TMS treatment outcomes.

Do bipolar disorder soft signs impact outcomes following Transcranial Magnetic Stimulation (TMS) therapy for depression?

BACKGROUND

Transcranial Magnetic Stimulation (TMS) is not currently FDA approved for depressed patients with bipolar disorder (BD), but many unipolar depressed patients presenting for TMS have soft signs of bipolarity. It is not known whether or not these soft signs portend differential outcomes.

OBJECTIVE

To investigate the relationship between BD soft signs and TMS treatment outcomes in a naturalistic treatment setting.

METHODS

We conducted a retrospective chart review of MDD patients (n = 105) treated with TMS. BD diathesis was defined by responses to a modified version of the Mood Disorder Questionnaire and family history.

RESULTS

TMS response rates for the group with BD diathesis and the group without were equivalent using two self-report depression severity scales. Remission rate was significantly lower for the bipolar soft signs group (13.5% versus 30.2%; p = 0.04) on one scale. This result does not hold when corrected for multiple comparisons. We did not observe switch to mania.

LIMITATIONS

These data are limited to patients diagnosed with unipolar depression with "soft" bipolar features defined by subthreshold symptoms. The results cannot be extrapolated to patients with a full bipolar diagnosis.

CONCLUSION

Bipolar diathesis in MDD is not a safety concern but may lead to somewhat lower remission rates when considering TMS treatment.

Behavioral activation therapy during transcranial magnetic stimulation for major depressive disorder

BACKGROUND

Behavioral Activation (BA) Therapy and Transcranial Magnetic Stimulation (TMS) have each been shown to be effective in the treatment of adult outpatients with major depressive disorder (MDD). Combining both treatments may produce synergistic antidepressant outcomes.

METHODS

We developed a new protocol for incorporating a simplified version of BA during a standard 6-week course of TMS and it was pilot tested in 11 consecutively treated outpatients with treatment resistant depression (TRD). BA was delivered in a 5-10 min interval daily prior to the start of TMS. Engagement in BA was measured by tracking the setting and attainment of between session "goals" during the course of TMS treatment. The Inventory of Depressive Symptoms (IDS-SR), the 9-item Patient Health Questionnaire (PHQ-9), and the Snaith-Hamilton Pleasure Scale (SHAPS) were used to measure overall symptom improvement.

RESULTS

Patients who underwent a combined BA + TMS protocol demonstrated an average goal completion rate of 77% along with overall symptom improvement as demonstrated by an average decrease of 47%, 55%, and 39% in IDS-SR, PHQ-9, and SHAPS scores respectively. BA was easily incorporated into the daily routine of administering TMS procedures.

LIMITATIONS

There is inadequate power in this current investigation to compare treatment efficacy of BA + TMS to TMS alone.

CONCLUSION

Incorporation of a modified version of BA therapy into a standard acute course of TMS therapy is feasible, well tolerated, and holds potential for augmenting the efficacy of TMS treatment for patients with TRD.

5 Hz Repetitive transcranial magnetic stimulation for posttraumatic stress disorder comorbid with major depressive disorder

BACKGROUND

Standard clinical protocols for repetitive transcranial magnetic stimulation (rTMS) for major depressive disorder (MDD) apply 10 Hz pulses over left prefrontal cortex, yet little is known about the effects of rTMS in more diagnostically complex depressed patients.

OBJECTIVE/HYPOTHESIS

Posttraumatic stress disorder (PTSD) is commonly comorbid with MDD, and while rTMS has been shown to alleviate PTSD symptoms in preliminary studies, ideal parameters remain unclear. We conducted a prospective, open-label study of 5 Hz rTMS for patients with comorbid PTSD + MDD and hypothesized stimulation would reduce symptoms of both disorders.

METHODS

Outpatients (N = 40) with PTSD + MDD and at least moderate global severity were enrolled. 5 Hz rTMS included up to 40 daily sessions followed by a 5-session taper. Symptoms were measured using the PTSD Checklist (PCL-5) and Inventory of Depressive Symptomatology, Self-Report (IDS-SR). Baseline-to-endpoint changes were analyzed.

RESULTS

The intent-to-treat population included 35 participants. Stimulation significantly reduced PTSD symptoms (PCL-5 baseline mean ± SD score 52.2 ± 13.1 versus endpoint 34.0 ± 21.6; p < .001); 23 patients (48.6%) met a pre-defined categorical PTSD response criteria. MDD symptoms also improved significantly (IDS-SR, baseline 47.8 ± 11.9 to endpoint 30.9 ± 18.9; p < .001); 15 patients (42.9%) demonstrated categorical response and 12 (34.3%) remitted. PTSD and MDD symptom change was highly correlated (r = 0.91, p < .001).

LIMITATIONS

Unblinded single-arm study, with modest sample size.

CONCLUSION

Significant and clinically meaningful reductions in both MDD and PTSD symptoms were observed following stimulation. The preliminary efficacy of 5 Hz rTMS for both symptom domains in patients with comorbid disorders supports future controlled studies.

Network Mechanisms of Clinical Response to Transcranial Magnetic Stimulation in Posttraumatic Stress Disorder and Major Depressive Disorder

BACKGROUND

Repetitive transcranial magnetic stimulation (TMS) therapy can modulate pathological neural network functional connectivity in major depressive disorder (MDD). Posttraumatic stress disorder is often comorbid with MDD, and symptoms of both disorders can be alleviated with TMS therapy. This is the first study to evaluate TMS-associated changes in connectivity in patients with comorbid posttraumatic stress disorder and MDD.

METHODS

Resting-state functional connectivity magnetic resonance imaging was acquired before and after TMS therapy in 33 adult outpatients in a prospective open trial. TMS at 5 Hz was delivered, in up to 40 daily sessions, to the left dorsolateral prefrontal cortex. Analyses used a priori seeds relevant to TMS, posttraumatic stress disorder, or MDD (subgenual anterior cingulate cortex [sgACC], left dorsolateral prefrontal cortex, hippocampus, and basolateral amygdala) to identify imaging predictors of response and to evaluate clinically relevant changes in connectivity after TMS, followed by leave-one-out cross-validation. Imaging results were explored using data-driven multivoxel pattern activation.

RESULTS

More negative pretreatment connectivity between the sgACC and the default mode network predicted clinical improvement, as did more positive amygdala-to-ventromedial prefrontal cortex connectivity. After TMS, symptom reduction was associated with reduced connectivity between the sgACC and the default mode network, left dorsolateral prefrontal cortex, and insula, and reduced connectivity between the hippocampus and the salience network. Multivoxel pattern activation confirmed seed-based predictors and correlates of treatment outcomes.

CONCLUSIONS

These results highlight the central role of the sgACC, default mode network, and salience network as predictors of TMS response and suggest their involvement in mechanisms of action. Furthermore, this work indicates that there may be network-based biomarkers of clinical response relevant to these commonly comorbid disorders.

A randomized, sham-controlled study of maintenance rTMS for treatment-resistant depression (TRD)

A few open-labeled studies have investigated the use of maintenance rTMS to prevent relapse for treatment-resistant depression (TRD) after rTMS treatment. We aim to assess the benefits of maintenance rTMS treatment for TRD patients who respond to rTMS treatment using a randomized, double-blind controlled design. Fifty eight TRD patients received rTMS over one month in an open-labeled design study (phase I). Responder patients were then randomized into active and sham high-frequency rTMS groups for the subsequent eleven months (phase II). The regularity of sessions was gradually reduced. The antidepressant effect of rTMS was evaluated using the Hamilton Depression Rating Scale (HDRS). Intention-to-treat analysis was performed to assess the effectiveness of maintenance sessions. Of the 58 patients included, 35 patients were responders after one month of active rTMS (phase I), and 17 patients were randomized for the maintenance sessions (phase II). The delta HDRS scores demonstrated a significant improvement between the first month and the fourth month in active group in comparison with sham group (phase II). There was no significant difference between these two groups for other periods of time. Repetitive TMS could represent a novel strategy for preventing relapse in TRD patients who respond to rTMS treatment. These results should be confirmed in a larger sample.

Affective Processing in Non-invasive Brain Stimulation Over Prefrontal Cortex

The prefrontal cortex (PFC) is the most frequently targeted brain region by non-invasive brain stimulation (NBS) studies. Non-invasively stimulating the PFC has been shown to both modulate affective processing and improve the clinical symptoms of several psychiatric disorders, such as depression and schizophrenia. The magnitude of the modulation depends on several factors, including the stimulation frequency, the number of stimulation sessions, and the specific sub-region of the PFC that is stimulated. Although some of the potential underlying mechanisms have been identified, the exact mechanisms that underlie these cognitive and affective changes remain unclear. The present review aims to summarize recent advances in the study of affective processing using NBS over the PFC. We will provide a theoretical framework for better understanding how affective processing changes are induced by NBS, with the goal of providing testable hypotheses for future studies.

Transcranial magnetic stimulation for treatment-resistant depression: Naturalistic treatment outcomes for younger versus older patients

BACKGROUND

Repetitive transcranial magnetic stimulation (TMS) has been shown to be safe and effective for treatment-resistant depression (TRD) in the general adult population. Efficacy among older (≥60 years) patients, who have a greater burden of cognitive, physical, and functional impairment compared to their younger counterparts, remains unclear. The current study aimed to characterize antidepressant response to an acute course of TMS therapy among patients aged ≥60 years compared to those <60 years in naturalistic clinical practice settings.

METHODS

Data were retrospectively collected and pooled for adults with TRD (N =231; n =75 aged ≥60 years and n = 156 <60 years) who underwent an acute course of outpatient TMS therapy at two outpatient clinics. Self-report depression scales were administered at baseline and end of acute treatment. Change on continuous measures and categorical outcomes were compared across older vs. younger patients.

RESULTS

Both age groups showed significant improvements in depression symptoms. Response and remission rates did not differ between groups. Age group was not a significant predictor of change in depression severity, nor of clinical response or remission, in a model controlling for other predictors (all p>.05).

LIMITATIONS

Limitations include reliance on self-report clinical measures and variability in comorbidity and concurrent pharmacotherapy due to the naturalistic nature of the study.

CONCLUSIONS

Results suggest that effectiveness of TMS for TRD is not differentially modified by age. Based on these naturalistic data, age alone should not be considered a contraindication or poor prognostic indicator of the antidepressant efficacy of TMS.

5-Hz Transcranial Magnetic Stimulation for Comorbid Posttraumatic Stress Disorder and Major Depression

Current treatment options for posttraumatic stress disorder (PTSD) offer modest benefits, underscoring the need for new treatments. Repetitive transcranial magnetic stimulation (rTMS) depolarizes neurons in a targeted brain region with magnetic fields typically pulsed at low (1 Hz) or high (10 Hz) frequency to relieve major depressive disorder (MDD). Prior work suggests an intermediate pulse frequency, 5 Hz, is also efficacious for treating comorbid depressive and anxiety symptoms. In this chart review study, we systematically examined the clinical and safety outcomes in 10 patients with comorbid MDD and PTSD syndromes who received 5-Hz rTMS therapy at the Providence VA Medical Center Neuromodulation Clinic. Self-report scales measured illness severity prior to treatment, after every 5 treatments, and upon completion of treatment. Results showed significant reduction in symptoms of PTSD (p = .003, effect size = 1.12, 8/10 with reliable change) and MDD (p = .005, effect size = 1.09, 6/10 with reliable change). Stimulation was well tolerated and there were no serious adverse events. These data indicate 5-Hz rTMS may be a useful option to treat these comorbid disorders. Larger, controlled trials are needed to confirm the benefits of 5-Hz protocols observed in this pilot study.