Repetitive Transcranial Magnetic Stimulation with Resting-State Network Targeting for Treatment-Resistant Depression in Traumatic Brain Injury: A Randomized, Controlled, Double-Blinded Pilot Study

Resting State Functional Connectivity Biomarkers of Treatment Response in Mood Disorders: A Review

There are currently no validated treatment biomarkers in psychiatry. Resting State Functional Connectivity (RSFC) is a popular method for investigating the neural correlates of mood disorders, but the breadth of the field makes it difficult to assess progress toward treatment response biomarkers. In this review, we followed general PRISMA guidelines to evaluate the evidence base for mood disorder treatment biomarkers across diagnoses, brain network models, and treatment modalities. We hypothesized that no treatment biomarker would be validated across these domains or with independent datasets. Results are organized, interpreted, and discussed in the context of four popular analytic techniques: (1) reference region (seed-based) analysis, (2) independent component analysis, (3) graph theory analysis, and (4) other methods. Cortico-limbic connectivity is implicated across studies, but there is no single biomarker that spans analyses or that has been replicated in multiple independent datasets. We discuss RSFC limitations and future directions in biomarker development.

Accelerated repetitive transcranial magnetic stimulation in the treatment of post-concussion symptoms due to mild traumatic brain injury: a pilot study

Objective: To investigate the feasibility, tolerability, and efficacy of twice-daily, low frequency (LF) repetitive transcranial magnetic stimulation (rTMS) over the right dorsolateral prefrontal cortex (DLPFC) in the reduction of chronic post-concussion symptoms (PCS) in patients who have suffered a mild traumatic brain injury (mTBI).Methods: 15 patients with mTBI received 30 sessions of twice-daily LF rTMS (1 Hz) over the right DLPFC. Post-concussion symptoms, pain, disability, fatigue, apathy, agitation, and mood were assessed by a psychiatrist pre- and post-treatment. Cognitive testing was also performed pre-, mid-, and post-rTMS.Results: All participants completed treatment with no serious adverse events. Significant improvements were observed in overall post-concussion symptoms, disability and pain ratings, as well as depression and anxiety symptoms. There was no significant change in overall executive functioning, fatigue severity, apathy, or agitation. Cognitive testing revealed improvements in verbal fluency, working memory, selective attention, and cognitive processing speed.Conclusions: This small-sample pilot study suggests that twice-daily, LF rTMS over the right DLPFC can be safely and tolerably applied and has the potential to improve post-concussion symptoms as well as elements of mood and cognition in patients with mTBI. Larger, sham-controlled studies will be important to confirm these observations.

Transcranial Magnetic Stimulation for the Treatment of Concussion: A Systematic Review

BACKGROUND

Post-concussive symptoms (PCSs) are common, disabling, and challenging to manage. Evolving models of concussion pathophysiology suggest evidence of brain network dysfunction that may be amenable to neuromodulation. Repetitive transcranial magnetic stimulation (rTMS) has emerged as a potential novel treatment option for PCSs.

OBJECTIVES

To systematically review rTMS trials for the treatment of symptoms following concussion/mild traumatic brain injury (mTBI).

MATERIALS AND METHODS

We conducted a systematic review of Pubmed/Medline, Embase, and PsychINFO databases were searched up to May 19, 2020. Studies were included if they were prospective rTMS treatment studies of patients with mTBI/concussion. Variables including patient demographics, study design, rTMS protocol parameters, primary outcome measures, and efficacy data were extracted and qualitatively synthesized. rTMS methodology and study quality were also evaluated.

RESULTS

Of the 342 studies identified, 11 met eligibility criteria and were included for synthesis. Forty-one percent of patients were female and age ranged from 18 to 65 (average age = 38.5 years). Post-concussive depression (seven studies) and headache (four studies) were the most commonly investigated symptoms. The majority of trials were sham-controlled with randomized control trial (RCT) designs, but all were small pilot samples (n < 30). Methodological heterogeneity and a low number of identified trials precluded quantitative meta-analysis. Regarding rTMS for post-concussive depression, positive results were found in two out of four studies with depression as a primary outcome, and all three studies that assessed depression as a secondary outcome. All four rTMS studies for post-concussive headache reported positive results.

CONCLUSIONS

rTMS for the treatment of concussion/mTBI shows promising preliminary results for post-concussive depression and headache, symptoms that otherwise have limited effective treatment options. More studies with larger sample sizes are needed to further establish potential efficacy.

Sex Differences in Neuromodulation Treatment Approaches for Traumatic Brain Injury: A Scoping Review

OBJECTIVE

Neuromodulatory brain stimulation interventions for traumatic brain injury (TBI)-related health sequelae, such as psychiatric, cognitive, and pain disorders, are on the rise. Because of disproportionate recruitment and epidemiological reporting of TBI-related research in men, there is limited understanding of TBI development, pathophysiology, and treatment intervention outcomes in women. With data suggesting sex-related variances in treatment outcomes, it is important that these gaps are addressed in emerging, neuromodulatory treatment approaches for TBI populations.

METHODS

Four research databases (PubMED, EMBASE, CINAHL, and PsycINFO) were electronically searched in February 2020.

DESIGN

This PRISMA Scoping Review (PRISMA-ScR)-guided report contextualizes the importance of reporting sex differences in TBI + neuromodulatory intervention studies and summarizes the current state of reporting sex differences when investigating 3 emerging interventions for TBI outcomes.

RESULTS

Fifty-four studies were identified for the final review including 12 controlled trials, 16 single or case series reports, and 26 empirical studies. Across all studies reviewed, 68% of participants were male, and only 7 studies reported sex differences as a part of their methodological approach, analysis, or discussion.

CONCLUSION

This review is hoped to update the TBI community on the current state of evidence in reporting sex differences across these 3 neuromodulatory treatments of post-TBI sequelae. The proposed recommendations aim to improve future research and clinical treatment of all individuals suffering from post-TBI sequelae.

Use of Repetitive Transcranial Magnetic Stimulation in the Treatment of Neuropsychiatric and Neurocognitive Symptoms Associated With Concussion in Military Populations

BACKGROUND

Since the year 2000, over 342 000 military service members have experienced a concussion, often associated with chronic neuropsychiatric and neurocognitive symptoms. Repetitive transcranial magnetic stimulation (rTMS) protocols have been developed for many of these symptoms in the general population.

OBJECTIVE

To conduct a scoping review of the literature on rTMS for neuropsychological and neurocognitive symptoms following concussion.

METHODS

PubMed and Google Scholar search engines identified 9 articles, written in English, corresponding to the search terms TBI or concussion; and TMS or rTMS; and depression, PTSD, or cognition. Studies that were not therapeutic trials or case reports, did not have neuropsychiatric or neurocognitive primary outcome measures, or described samples where 80% or more of the cohort did not have a TBI were excluded.

RESULTS

There were no reports of seizures nor difference in the frequency or quality of other adverse events as compared with the broader rTMS literature, supporting the safety of rTMS in this population. Support for the efficacy of rTMS for the treatment of neuropsychiatric and neurocognitive symptoms, in this population, is limited.

CONCLUSIONS

Large-scale, innovative, neuroscience-informed protocols are recommended to elucidate the potential utility of rTMS for the complex neuropsychiatric and neurocognitive symptoms associated with military concussions.

Customizing TMS Applications in Traumatic Brain Injury Using Neuroimaging

Optimizing transcranial magnetic stimulation (TMS) treatments in traumatic brain injury (TBI) and co-occurring conditions may benefit from neuroimaging-based customization.

PARTICIPANTS

Our total sample (N = 97) included 58 individuals with TBI (49 mild, 8 moderate, and 1 severe in a state of disordered consciousness), of which 24 had co-occurring conditions (depression in 14 and alcohol use disorder in 10). Of those without TBI, 6 individuals had alcohol use disorder and 33 were healthy controls. Of our total sample, 54 were veterans and 43 were civilians.

DESIGN

Proof-of-concept study incorporating data from 5 analyses/studies that used multimodal approaches to integrate neuroimaging with TMS.

MAIN MEASURES

Multimodal neuroimaging methods including structural magnetic resonance imaging (MRI), MRI-guided TMS navigation, functional MRI, diffusion MRI, and TMS-induced electric fields. Outcomes included symptom scales, neuropsychological tests, and physiological measures.

RESULTS

It is feasible to use multimodal neuroimaging data to customize TMS targets and understand brain-based changes in targeted networks among people with TBI.

CONCLUSIONS

TBI is an anatomically heterogeneous disorder. Preliminary evidence from the 5 studies suggests that using multimodal neuroimaging approaches to customize TMS treatment is feasible. To test whether this will lead to increased clinical efficacy, studies that integrate neuroimaging and TMS targeting data with outcomes are needed.

The management of depression following traumatic brain injury: A systematic review with meta-analysis

BACKGROUND

Traumatic brain injury (TBI) is prevalent. Declining mortality has led to increasing survivors with chronic sequalae, including depression. With a lack of guidelines, this review aims to provide a comprehensive, evidence-based summary of the management of depression following TBI.

METHODS

Systematic searches were conducted for quasi-experimental and randomized controlled trials (RCTs) assessing pharmacotherapy, psychological interventions, and transcranial magnetic stimulation (TMS). Databases searched CENTRAL, Medline, Embase, CINAHL, PsycINFO, Web of Science, and ProQuest dissertations. Data extraction and risk-of-bias tools were used. Where possible, outcomes were combined into meta-analyses.

RESULTS

2719 studies were identified. After abstract screening and full-text reading, 34 remained. Prophylactic sertraline significantly reduced the odds of depression (OR (odds ratio) = 0.31 [95%CI (confidence interval) = 0.12 to 0.82]). Meta-analysis of RCT's showed TMS to have the greatest reduction in depression severity (SMD (Standardized-Mean-Difference) = 2.43 [95%CI = 1.24 to 3.61]). Stimulants were the only treatment superior to control (SMD = -1.03 [95%CI = - 1.6 to -0.47]).

CONCLUSION

Methylphenidate was the most effective pharmacotherapy. Sertraline appears effective for prevention. The efficacy of psychological interventions is unclear. TMS as a combination therapy appears promising. Heterogeneity of study populations and dearth of evidence means results should be interpreted cautiously.

Global connectivity and local excitability changes underlie antidepressant effects of repetitive transcranial magnetic stimulation

Repetitive transcranial magnetic stimulation (rTMS) is a commonly- used treatment for major depressive disorder (MDD). However, our understanding of the mechanism by which TMS exerts its antidepressant effect is minimal. Furthermore, we lack brain signals that can be used to predict and track clinical outcome. Such signals would allow for treatment stratification and optimization. Here, we performed a randomized, sham-controlled clinical trial and measured electrophysiological, neuroimaging, and clinical changes before and after rTMS. Patients (N = 36) were randomized to receive either active or sham rTMS to the left dorsolateral prefrontal cortex (dlPFC) for 20 consecutive weekdays. To capture the rTMS-driven changes in connectivity and causal excitability, resting fMRI and TMS/EEG were performed before and after the treatment. Baseline causal connectivity differences between depressed patients and healthy controls were also evaluated with concurrent TMS/fMRI. We found that active, but not sham rTMS elicited (1) an increase in dlPFC global connectivity, (2) induction of negative dlPFC-amygdala connectivity, and (3) local and distributed changes in TMS/EEG potentials. Global connectivity changes predicted clinical outcome, while both global connectivity and TMS/EEG changes tracked clinical outcome. In patients but not healthy participants, we observed a perturbed inhibitory effect of the dlPFC on the amygdala. Taken together, rTMS induced lasting connectivity and excitability changes from the site of stimulation, such that after active treatment, the dlPFC appeared better able to engage in top-down control of the amygdala. These measures of network functioning both predicted and tracked clinical outcome, potentially opening the door to treatment optimization.

Distinct Symptom-Specific Treatment Targets for Circuit-Based Neuromodulation

OBJECTIVE

Treatment of different depression symptoms may require different brain stimulation targets with different underlying brain circuits. The authors sought to identify such targets, which could improve the efficacy of therapeutic brain stimulation and facilitate personalized therapy.

METHODS

The authors retrospectively analyzed two independent cohorts of patients who received left prefrontal transcranial magnetic stimulation (TMS) for treatment of depression (discovery sample, N=30; active replication sample, N=81; sham replication sample, N=87). Each patient's TMS site was mapped to underlying brain circuits using functional connectivity MRI from a large connectome database (N=1,000). Circuits associated with improvement in each depression symptom were identified and then clustered based on similarity. The authors tested for reproducibility across data sets and whether symptom-specific targets derived from one data set could predict symptom improvement in the other independent cohort.

RESULTS

The authors identified two distinct circuit targets effective for two discrete clusters of depressive symptoms. Dysphoric symptoms, such as sadness and anhedonia, responded best to stimulation of one circuit, while anxiety and somatic symptoms responded best to stimulation of a different circuit. These circuit maps were reproducible, predicted symptom improvement in independent patient cohorts, and were specific to active compared with sham stimulation. The maps predicted symptom improvement in an exploratory analysis of stimulation sites from 14 clinical TMS trials.

CONCLUSIONS

Distinct clusters of depressive symptoms responded better to different TMS targets across independent retrospective data sets. These symptom-specific targets can be prospectively tested in a randomized clinical trial. This data-driven approach for identifying symptom-specific targets may prove useful for other disorders and facilitate personalized neuromodulation therapy.

Treatment of Depression After Traumatic Brain Injury: A Systematic Review Focused on Pharmacological and Neuromodulatory Interventions

BACKGROUND

Depression is the most common psychiatric sequela after traumatic brain injury (TBI) and poses a variety of treatment challenges. There is a lack of clinical trials focused on biological interventions used to manage TBI depression.

OBJECTIVE

The aim of this systematic review is to summarize the current evidence of psychotropic and neuromodulatory interventions used to treat TBI depression and to provide directions for future research.

METHODS

Key words were used to describe the following search terms: "traumatic brain injury", "depression", "pharmacological/drug therapy", and "neuromodulation". Studies focused on pharmacotherapy or neuromodulation in TBI depression were identified in 5 databases: Medline (PubMed), EMBASE (Embase.com), the Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register), PsycINFO (EbscoHost), and Web of Science. Article inclusion/exclusion using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-based systematic protocol of extraction and evaluation was applied. Level of evidence for each study was determined using the American Academy of Neurology criteria.

RESULTS

The initial search provided 1473 citations. Twenty-two studies met inclusion criteria. Sixteen studies explored pharmacological interventions with emphasis on serotonergic agents. Results between studies were conflicting, and interventions did not always outperform placebos, although sertraline provided the highest level of evidence for treatment of TBI depression. Six studies examining neuromodulatory interventions show preliminary evidence of efficacy with a range of interventions and modes of delivery used.

CONCLUSIONS

Additional research including large-sample randomized-controlled trials using pharmacological, neuromodulation, or combination treatment is needed. These studies should incorporate premorbid psychosocial functioning, preinjury psychiatric disease, cognitive deficits, and functional recovery when examining outcomes.

Repetitive transcranial magnetic stimulation in traumatic brain injury: Evidence from animal and human studies

We provide here the first systematic review on the studies dealing with repetitive transcranial magnetic stimulation (rTMS) for traumatic brain injury (TBI) in animals and humans. Several experimental studies in animal models have explored with promising results the use of rTMS to enhance neuroprotection and recovery after TBI. However, there are surprisingly few studies that have obtained substantial evidence regarding effects of rTMS in humans with TBI, many of them are case reports investigating the heterogeneous conditions linked to TBI. The most studies have investigated the effects of rTMS in subjects with post-traumatic depression and variable effects have been observed. rTMS has been proposed as an experimental approach for the treatment of disorders of consciousness (DOC), but in subjects with TBI therapeutic effects on DOC have also been variously documented. Beneficial effects have been reported in subjects with cognitive/emotional disturbances and auditory dysfunction (tinnitus and hallucinations), although the results are somewhat conflicting. rTMS applied over the left prefrontal cortex may relieve, at least transiently, post-traumatic headache. Isolated rTMS studies have been performed in TBI patients with motor impairment, chronic dizziness or pain. Especially whether provided in combination, rTMS and neurorehabilitation may be synergistic in the potential to translate experimental findings in the clinical practice. In order to reach definitive conclusions, well-designed randomized controlled studies with larger patient samples, improved design and optimized rTMS setup, are warranted to verify and corroborate the initial promising findings.

Resting-state network mapping in neurosurgical practice: a review

Resting-state functional MRI (rs-fMRI) is a well-established method for studying intrinsic connectivity and mapping the topography of functional networks in the human brain. In the clinical setting, rs-fMRI has been used to define functional topography, typically language and motor systems, in the context of preoperative planning for neurosurgery. Intraoperative mapping of critical speech and motor areas with electrocortical stimulation (ECS) remains standard practice, but preoperative noninvasive mapping has the potential to reduce operative time and provide functional localization when awake mapping is not feasible. Task-based fMRI has historically been used for this purpose, but it can be limited by the young age of the patient, cognitive impairment, poor cooperation, and need for sedation. Resting-state fMRI allows reliable analysis of all functional networks with a single study and is inherently independent of factors affecting task performance. In this review, the authors provide a summary of the theory and methods for resting-state network mapping. They provide case examples illustrating clinical implementation and discuss limitations of rs-fMRI and review available data regarding performance in comparison to ECS. Finally, they discuss novel opportunities for future clinical applications and prospects for rs-fMRI beyond mapping of regions to avoid during surgery but, instead, as a tool to guide novel network-based therapies.

The Effect of Traditional Chinese Mind-Body Exercise (Baduanjin) and Brisk Walking on the Dorsal Attention Network in Older Adults With Mild Cognitive Impairment

A growing number of studies have shown that mind-body exercise is beneficial to cognitive function, especially memory, in elderly MCI patients. However, few studies have explored the effect of mind-body exercise on the attention of MCI population. We recruited 69 participants and divided them equally into Baduanjin, brisk walking (BWK) exercise or usual physical activity (UAP) control groups. The two exercise groups performed 60 min of exercise three times per week for 24 weeks. All subjects underwent whole-brain functional MRI and assessment of attentional abilities, including selective, divided, and sustained attention, and processing speed at baseline and after 24 weeks. The results show that: Baduanjin exercise significantly increased the selective attention of MCI patients, and Dorsal attention network (DAN) of Baduanjin exercise group exhibited functional connectivity decreased in right rolandic operculum (ROL. R), right middle temporal gyrus (MTG. R), right supramarginal inferior parietal, angular gyri (IPL. R), right precuneus (PCUN. R), and right fusiform gyrus (FFG. R) regions compared with the other two groups. The BWK exercise group had obviously functional connectivity increased in IPL. R and decreased in the MTG. R region compared to that in the UAP group. But no significant association between the changes of functional connectivity of DAN and the change of attentional ability test was observed. Thus, our data indicated Baduanjin exercise may be a potential beneficial intervention to improve the attention of the elderly with MCI. Further study with more samples is necessary to elucidate its imaging mechanism.

Using Functional Near-Infrared Spectroscopy to Study the Effect of Repetitive Transcranial Magnetic Stimulation in Concussion: A Two-Patient Case Study

Background: Approximately 25% of concussion patients experience persistent post-concussion symptoms (PPCS). Repetitive transcranial magnetic stimulation (rTMS) has been explored as a treatment, and functional near-infrared spectroscopy (fNIRS) may be a cost-effective method for assessing response. Objectives: Evaluate rTMS for the treatment of PPCS and introduce fNIRS as a method of assessing treatment response. Methods: Design: Two-patient case study. Setting: Calgary Brain Injury Program. Participants: 47 and 49 years. male, with PPCS for 1-2 years (headache, cognitive difficulties, nausea, visual difficulties, irritability, anxiety, poor mood, sleep, and fatigue). Intervention: 10 sessions of rTMS therapy to the left dorsolateral prefrontal cortex (DLPFC), at 10 Hz (600 pulses) and 70% of resting motor threshold amplitude. Participants completed an 8-week headache diary and a battery of clinical questionnaires prior to each fNIRS session. fNIRS: Hemodynamic changes were recorded over the frontoparietal cortex during rest, finger tapping, and a graded working memory test. fNIRS was completed pre-rTMS, following rTMS (day 14), and at 1-month post-rTMS (day 45). For comparison, two healthy, sex-matched controls were scanned with fNIRS once daily for five consecutive days. Results: Clinical scores improved (headache severity, MoCA, HIT-6, PHQ-9, GAD-7, QOLIBRI, RPSQ, BCPSI) or remained stable (PCL-5, headache frequency) post-rTMS, for both participants. Participant 1 reported moderate symptom burden, and a fNIRS task-evoked hemodynamic response showing increased oxyhemoglobin was observed following a working memory task, as expected. Participant 2 exhibited a high symptom burden pre-treatment, with abnormal fNIRS hemodynamic response where oxyhemoglobin declined, in response to task. One month following rTMS treatment, participant 2 had a normal fNIRS hemodynamic response to task, corresponding to significant improvements in clinical outcomes. Conclusion: This case study suggests fNIRS may be sensitive to physiological changes that accompany rTMS treatment. Further studies exploring fNIRS as a cost-effective technology for monitoring rTMS response in patients with PPCS are suggested.

Changes in Global and Nodal Networks in Patients With Unipolar Depression After 3-Week Repeated Transcranial Magnetic Stimulation Treatment

Objectives: Repeated transcranial magnetic stimulation (rTMS) therapy has been applied in depressive disorders, but its neurobiological effect has not been well understood. Changes in cortical source network after treatment need to be confirmed. The present study investigated the effect of 3-week rTMS therapy on the symptom severity and cortical source network in patients with unipolar depression. Methods: Thirty-five patients with unipolar major depressive disorder participated in the study. High-frequency (10 Hz) rTMS was applied at the left dorsolateral prefrontal cortex during 3 weeks (five consecutive weekdays every week). Clinical symptoms were examined using the Hamilton Rating Scale for Depression and Anxiety. The resting state electroencephalography was recorded with 62 scalp channels before and after rTMS treatment. Results: Clinical symptoms significantly improved after rTMS treatment in both the active (p = 0.001) and sham groups (p = 0.002). However, an increased cortical source network in global and nodal levels was observed only in the active group after a 3-week treatment. Conclusions: The present study indicates that rTMS treatment leads to improved symptoms in patients with unipolar depression. Furthermore, treatment outcome of real effect was assured in changes of cortical source network.