Accelerated transcranial magnetic stimulation for the treatment of Patients with depression: A review

Neuromodulatory transcranial magnetic stimulation (TMS) changes functional connectivity proportional to the electric-field induced by the TMS pulse

OBJECTIVE

Transcranial magnetic stimulation (TMS) can efficiently and robustly modulate synaptic plasticity, but little is known about how TMS affects functional connectivity (rs-fMRI). Accordingly, this project characterized TMS-induced rsFC changes in depressed patients who received 3 days of left prefrontal intermittent theta burst stimulation (iTBS).

METHODS

rs-fMRI was collected from 16 subjects before and after iTBS. Correlation matrices were constructed from the cleaned rs-fMRI data. Electric-field models were conducted and used to predict pre-post changes in rs-fMRI. Site by orientation heatmaps were created for vectors centered on the stimulation site and a control site (contralateral motor cortex).

RESULTS

For the stimulation site, there was a clear relationship between both site and coil orientation, and connectivity changes. As distance from the stimulation site increased, prediction accuracy decreased. Similarly, as eccentricity from the optimal orientation increased, prediction accuracy decreased. The systematic effects described above were not apparent in the heatmap centered on the control site.

CONCLUSIONS

These results suggest that rs-fMRI following iTBS changes systematically as a function of the distribution of electrical energy delivered from the TMS pulse, as represented by the e-field model.

SIGNIFICANCE

This finding lays the groundwork for future studies to individualize TMS targeting based on how predicted rs-fMRI changes might impact psychiatric symptoms.

Efficacy of accelerated deep transcranial magnetic stimulation wi̇th double cone coi̇l in obsessive-compulsive disorder: A double-blind, placebo-controlled study

High-frequency deep transcranial magnetic stimulation (dTMS) targeting the medial prefrontal cortex (mPFC) and the anterior cingulate cortex (ACC) with an H-coil has received approval from the Food and Drug Administration for the treatment of obsessive-compulsive disorder (OCD). Nevertheless, there is limited evidence regarding the efficacy of a similar procedure performed using a double-cone coil or in an accelerated regimen. In this study, patients in the active TMS group (n = 14) underwent stimulation of the mPFC and ACC twice daily at a frequency of 20 Hz for three weeks, using a double-cone coil. The same procedure was applied to the control group (n = 15) using a placebo coil. Throughout the study, the patients continued their antidepressant and/or antipsychotic treatments at the same dose. Following treatment, the active TMS group exhibited a more significant reduction in Yale-Brown Obsessive-Compulsive Scale scores (pre-treatment: 25.36 ± 5.4, post-treatment: 18.43 ± 6.86) and Hamilton Anxiety Rating Scale scores (pre-treatment: 10.6 ± 3.5, post-treatment: 6.7 ± 2.7) compared to the sham TMS group. However, there was no statistically significant reduction in symmetry-related obsessive-compulsive symptoms in the TMS group compared to the sham TMS group. dTMS applied to the mPFC and ACC, using a double-cone coil at a 20-Hz frequency twice daily for three weeks, was found to be effective as an adjunctive treatment for treatment-resistant OCD.

Brain stimulation for treatment-resistant depression

Depression is one of the main public health problems in the world, having a high prevalence and being considered the main cause of disability. An important portion of patients does not respond to treatment with the initial trial of conventional antidepressants in the current depressive episode of moderate to severe intensity, which characterizes treatment-resistant depression. In this context, non-invasive neuromodulation procedures use an electric current or magnetic field to modulate the central nervous system, and they represent a new option for patients with treatment-resistant depression.

Accelerated Repetitive Transcranial Magnetic Stimulation to Treat Major Depression: The Past, Present, and Future

Repetitive transcranial magnetic stimulation (rTMS) is an effective and evidence-based therapy for treatment-resistant major depressive disorder. A conventional course of rTMS applies 20-30 daily sessions over 4-6 weeks. The schedule of rTMS delivery can be accelerated by applying multiple stimulation sessions per day, which reduces the duration of a treatment course with a predefined number of sessions. Accelerated rTMS reduces time demands, improves clinical efficiency, and potentially induces faster onset of antidepressant effects. However, considerable heterogeneity exists across study designs. Stimulation protocols vary in parameters such as the stimulation target, frequency, intensity, number of pulses applied per session or over a course of treatment, and duration of intersession intervals. In this article, clinician-researchers and neuroscientists who have extensive research experience in accelerated rTMS synthesize a consensus based on two decades of investigation and development, from early studies ("Past") to contemporaneous theta burst stimulation, a time-efficient form of rTMS gaining acceptance in clinical settings ("Present"). We propose descriptive nomenclature for accelerated rTMS, recommend avenues to optimize therapeutic and efficiency potential, and suggest using neuroimaging and electrophysiological biomarkers to individualize treatment protocols ("Future"). Overall, empirical studies show that accelerated rTMS protocols are well tolerated and not associated with serious adverse effects. Importantly, the antidepressant efficacy of accelerated rTMS appears comparable to conventional, once daily rTMS protocols. Whether accelerated rTMS induces antidepressant effects more quickly remains uncertain. On present evidence, treatment protocols incorporating high pulse dose and multiple treatments per day show promise and improved efficacy.

Investigating the Role of Maintenance TMS Protocols for Major Depression: Systematic Review and Future Perspectives for Personalized Interventions

Repetitive Transcranial Magnetic Stimulation (rTMS) has been approved by the FDA as an effective intervention for Treatment-Resistant Depression (TRD). However, there is little evidence about maintenance protocol necessity. The aim of this systematic review is to identify, characterize, and evaluate the current maintenance TMS protocols for MDD and TRD patients who have received acute treatment. A literature search was conducted following the PRISMA guidelines of 2015 on PubMed, Scopus, and Web of Science databases for publications up to March 2022. Fourteen articles were included. High protocol heterogeneity was observed. Most studies highlighted significant efficacy of maintenance protocols in decreasing relapse risk, suggesting that administering two or fewer stimulations per month is ineffective in sustaining an antidepressant effect or in reducing the risk of relapse in responder patients. The risk of relapse was most pronounced after five months from the acute treatment. Maintenance TMS appears to be a resourceful strategy to maintain acute antidepressant treatment effects, significantly reducing relapse risk. The ease of administering and the ability to monitor treatment adherence should be considered when evaluating the future use of maintenance TMS protocols. Further studies are needed to clarify the clinical relevance of overlapping acute TMS effects with maintenance protocols and to evaluate their long-term effectiveness.

Intensive rTMS for treatment-resistant depression patients with suicidal ideation: An open-label study

The advantages of intensive repetitive transcranial magnetic stimulation (rTMS) protocol are in the possible acute effect of the stimulation and in the possible reduction in the time required to achieve remission in depression. Here, we investigated the antidepressant effects and antisuicidal effects of a more intensive rTMS protocol for treatment-resistant depression (TRD) patients with suicidal ideation. Thirty-one outpatients were included in this study, including 22 military veterans and 9 non- militaries. The rTMS treatment consisted of 25 sessions, each session lasting 30 min (60 trains of 50 pulsations, 110 % resting motor threshold intensity) for a total of 3000 pulse. The total amount of stimulation (750,000 pulses) applied by our rTMS protocol was equivalent to that of a 5-week standard rTMS protocol. We found a significant effect of time on the 17-item Hamilton Depression Rating Scale (HAMD-17) scores and the Sheehan Disability Scale (SDS) scores. There was no difference in change in the HAMD-17 scores and SDS scores between the military veteran group and the non-military group between baseline and the week 4 assessment time point. The response rate of depression was 64.52 %, and the remission rate of depression was 51.61 % at day 5. 48.39 % and 35.48 % at week 4, respectively. All patients (100 %) met response criteria of suicidal ideation, and the remission rate was 87.09 % at day 5. The response rate was 83.87 % %, and the remission rate was 77.42 % at week 4. The accelerated high-dose rTMS treatment was well tolerated by all patients. Our intensive rTMS protocol is preliminarily safe and feasible. The TRD patients with suicidal ideation could benefit from much shorter exposure to this protocol with more efficacy in comparison with conventional rTMS protocol. In addition, intensive rTMS offers a promising treatment for military veteran populations.

A transdiagnostic review of safety, efficacy, and parameter space in accelerated transcranial magnetic stimulation

BACKGROUND

Accelerated transcranial magnetic stimulation (aTMS) is an emerging delivery schedule of repetitive TMS (rTMS). TMS is "accelerated" by applying two or more stimulation sessions within a day. This three-part review comprehensively reports the safety/tolerability, efficacy, and stimulation parameters affecting response across disorders.

METHODS

We used the PubMed database to identify studies administering aTMS, which we defined as applying at least two rTMS sessions within one day.

RESULTS

Our targeted literature search identified 85 aTMS studies across 18 diagnostic and healthy control groups published from July 2001 to June 2022. Excluding overlapping populations, 63 studies delivered 43,873 aTMS sessions using low frequency, high frequency, and theta burst stimulation in 1543 participants. Regarding safety, aTMS studies had similar seizure and side effect incidence rates to those reported for once daily rTMS. One seizure was reported from aTMS (0.0023% of aTMS sessions, compared with 0.0075% in once daily rTMS). The most common side effects were acute headache (28.4%), fatigue (8.6%), and scalp discomfort (8.3%), with all others under 5%. We evaluated aTMS efficacy in 23 depression studies (the condition with the most studies), finding an average response rate of 42.4% and remission rate of 28.4% (range = 0-90.5% for both). Regarding parameters, aTMS studies ranged from 2 to 10 sessions per day over 2-30 treatment days, 10-640 min between sessions, and a total of 9-104 total accelerated TMS sessions per participant (including tapering sessions). Qualitatively, response rate tends to be higher with an increasing number of sessions per day, total sessions, and total pulses.

DISCUSSION

The literature to date suggests that aTMS is safe and well-tolerated across conditions. Taken together, these early studies suggest potential effectiveness even in highly treatment refractory conditions with the added potential to reduce patient burden while also expediting response time. Future studies are warranted to systematically investigate how key aTMS parameters affect treatment outcome and durability.

Repetitive Transcranial Magnetic Stimulation for Adolescent Major Depressive Disorder: A Focus on Neurodevelopment

Adolescent depression is a potentially lethal condition and a leading cause of disability for this age group. There is an urgent need for novel efficacious treatments since half of adolescents with depression fail to respond to current therapies and up to 70% of those who respond will relapse within 5 years. Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising treatment for major depressive disorder (MDD) in adults who do not respond to pharmacological or behavioral interventions. In contrast, rTMS has not demonstrated the same degree of efficacy in adolescent MDD. We argue that this is due, in part, to conceptual and methodological shortcomings in the existing literature. In our review, we first provide a neurodevelopmentally focused overview of adolescent depression. We then summarize the rTMS literature in adult and adolescent MDD focusing on both the putative mechanisms of action and neurodevelopmental factors that may influence efficacy in adolescents. We then identify limitations in the existing adolescent MDD rTMS literature and propose specific parameters and approaches that may be used to optimize efficacy in this uniquely vulnerable age group. Specifically, we suggest ways in which future studies reduce clinical and neural heterogeneity, optimize neuronavigation by drawing from functional brain imaging, apply current knowledge of rTMS parameters and neurodevelopment, and employ an experimental therapeutics platform to identify neural targets and biomarkers for response. We conclude that rTMS is worthy of further investigation. Furthermore, we suggest that following these recommendations in future studies will offer a more rigorous test of rTMS as an effective treatment for adolescent depression.

Efficacy, efficiency and safety of high-frequency repetitive transcranial magnetic stimulation applied more than once a day in depression: A systematic review

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for depression but a standard course can be time-consuming. Of all rTMS protocols, high-frequency rTMS (HF rTMS) is the most studied and applied in clinical settings. Little is known about applying multiple sessions of HF rTMS per day, in so-called accelerated schedules.

METHODS

We systematically searched electronic records up to September 2019 for studies that applied HF rTMS in accelerated schedules to treat depression to review its efficacy, efficiency and safety. Treatment effect sizes of accelerated rTMS versus standard and sham rTMS were calculated from comparison studies and pooled to derive overall treatment effect.

RESULTS

Of 1,361 records screened, 12 met review criteria. Qualitative synthesis suggested accelerated HF rTMS was equally effective as once-daily scheduling in treating depression. It is equivocal if accelerated HF rTMS results in more rapid antidepressant response. Accelerated HF rTMS was well-tolerated. The small number of studies suitable for quantitative analysis led to pooled effect sizes that did not reach statistical significance.

LIMITATIONS

There was an overall paucity of studies examining the accelerated application of HF rTMS and even fewer studies comparing accelerated HF rTMS with once-daily or sham rTMS.

CONCLUSION

Our review found comparable antidepressant efficacy between accelerated and once-daily HF rTMS. Between group differences in therapeutic effect sizes were not clinically meaningful. More studies investigating accelerated rTMS protocols are needed to validate its utility and guide clinical decision making.

Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS): An update (2014-2018)

A group of European experts reappraised the guidelines on the therapeutic efficacy of repetitive transcranial magnetic stimulation (rTMS) previously published in 2014 [Lefaucheur et al., Clin Neurophysiol 2014;125:2150-206]. These updated recommendations take into account all rTMS publications, including data prior to 2014, as well as currently reviewed literature until the end of 2018. Level A evidence (definite efficacy) was reached for: high-frequency (HF) rTMS of the primary motor cortex (M1) contralateral to the painful side for neuropathic pain; HF-rTMS of the left dorsolateral prefrontal cortex (DLPFC) using a figure-of-8 or a H1-coil for depression; low-frequency (LF) rTMS of contralesional M1 for hand motor recovery in the post-acute stage of stroke. Level B evidence (probable efficacy) was reached for: HF-rTMS of the left M1 or DLPFC for improving quality of life or pain, respectively, in fibromyalgia; HF-rTMS of bilateral M1 regions or the left DLPFC for improving motor impairment or depression, respectively, in Parkinson's disease; HF-rTMS of ipsilesional M1 for promoting motor recovery at the post-acute stage of stroke; intermittent theta burst stimulation targeted to the leg motor cortex for lower limb spasticity in multiple sclerosis; HF-rTMS of the right DLPFC in posttraumatic stress disorder; LF-rTMS of the right inferior frontal gyrus in chronic post-stroke non-fluent aphasia; LF-rTMS of the right DLPFC in depression; and bihemispheric stimulation of the DLPFC combining right-sided LF-rTMS (or continuous theta burst stimulation) and left-sided HF-rTMS (or intermittent theta burst stimulation) in depression. Level A/B evidence is not reached concerning efficacy of rTMS in any other condition. The current recommendations are based on the differences reached in therapeutic efficacy of real vs. sham rTMS protocols, replicated in a sufficient number of independent studies. This does not mean that the benefit produced by rTMS inevitably reaches a level of clinical relevance.