Neuromodulation of OCD: A review of invasive and non-invasive methods

The Efficacy of Transcranial Magnetic Stimulation in the Treatment of Obsessive-Compulsive Disorder: An Umbrella Review of Meta-Analyses

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has been increasingly used for treating obsessive-compulsive disorder (OCD). Although several meta-analyses have explored its effectiveness and safety, there is no umbrella review specifically focused on rTMS for OCD. This umbrella review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and analyzed relevant meta-analyses on rTMS for OCD.

METHODS

Twenty-three articles were identified from PubMed, and after screening, 12 meta-analyses were included in the review. The studies analyzed in the meta-analyses ranged from 10 to 27, with total participants ranging from 282 to 791. The most commonly studied regions were the dorsolateral prefrontal cortex (DLPFC), supplementary motor area (SMA), and orbito-frontal cortex (OFC).

RESULT

The majority of the meta-analyses consistently supported the effectiveness of rTMS in reducing OCD symptoms when applied to the DLPFC and SMA. Encouraging results were also observed when targeting the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC) through deep transcranial magnetic stimulation (dTMS). However, there was a high level of heterogeneity in the findings of nine out of 12 meta-analyses.

CONCLUSION

In conclusion, existing evidence suggests that rTMS targeting the DLPFC and SMA consistently reduces OCD symptoms, but targeting the mPFC and ACC through dTMS shows variable results. However, the high heterogeneity in the study findings indicates a need for further research and standardization in the field.

Early-life seizures alter habit behavior formation and fronto-striatal circuit dynamics

Obsessive compulsive disorder (OCD) can occur comorbidly with epilepsy; both are complex, disruptive disorders that lower quality of life. Both OCD and epilepsy are disorders of hyperexcitable circuits, but it is unclear whether common circuit pathology may underlie the co-occurrence of these two neuropsychiatric disorders. Here, we induced early-life seizures (ELS) in rats to examine habit formation as a model for compulsive behaviors. Compulsive, repetitive behaviors in OCD utilize the same circuitry as habit formation. We hypothesized that rats with ELS could be more susceptible to habit formation than littermate controls, and that altered behavior would correspond to altered signaling in fronto-striatal circuits that underlie decision-making and action initiation. Here, we show instead that rats with ELS were significantly less likely to form habit behaviors compared with control rats. This behavioral difference corresponded with significant alterations to temporal coordination within and between brain regions that underpin the action to habit transition: 1) phase coherence between the lateral orbitofrontal cortex and dorsomedial striatum (DMS) and 2) theta-gamma coupling within DMS. Finally, we used cortical electrical stimulation as a model of transcranial magnetic stimulation (TMS) to show that temporal coordination of fronto-striatal circuits in control and ELS rats are differentially susceptible to potentiating and suppressive stimulation, suggesting that altered underlying circuit physiology may lead to altered response to therapeutic interventions such as TMS.

The current state, challenges, and future directions of deep brain stimulation for obsessive compulsive disorder

INTRODUCTION

Obsessive-compulsive disorder (OCD) is clinically and pathologically heterogenous, with symptoms often refractory to first-line treatments. Deep brain stimulation (DBS) for the treatment of refractory OCD provides an opportunity to adjust and individualize neuromodulation targeting aberrant circuitry underlying OCD. The tailoring of DBS therapy may allow precision in symptom control based on patient-specific pathology. Progress has been made in understanding the potential targets for DBS intervention; however, a consensus on an optimal target has not been agreed upon.

AREAS COVERED

A literature review of DBS for OCD was performed by querying the PubMed database. The following topics were covered: the evolution of DBS targeting in OCD, the concept of an underlying unified connectomic network, current DBS targets, challenges facing the field, and future directions which could advance personalized DBS in this challenging population.

EXPERT OPINION

To continue the increasing efficacy of DBS for OCD, we must further explore the optimal DBS response across clinical profiles and neuropsychiatric domains of OCD as well as how interventions targeting multiple points in an aberrant circuit, multiple aberrant circuits, or a connectivity hub impact clinical response. Additionally, biomarkers would be invaluable in programming adjustments and creating a closed-loop paradigm to address symptom fluctuation in daily life.

Deep Brain Stimulation beyond the Clinic: Navigating the Future of Parkinson's and Alzheimer's Disease Therapy

Deep brain stimulation (DBS) is a surgical procedure that uses electrical neuromodulation to target specific regions of the brain, showing potential in the treatment of neurodegenerative disorders such as Parkinson's disease (PD) and Alzheimer's disease (AD). Despite similarities in disease pathology, DBS is currently only approved for use in PD patients, with limited literature on its effectiveness in AD. While DBS has shown promise in ameliorating brain circuits in PD, further research is needed to determine the optimal parameters for DBS and address any potential side effects. This review emphasizes the need for foundational and clinical research on DBS in different brain regions to treat AD and recommends the development of a classification system for adverse effects. Furthermore, this review suggests the use of either a low-frequency system (LFS) or high-frequency system (HFS) depending on the specific symptoms of the patient for both PD and AD.

Proceedings of the 10th annual deep brain stimulation think tank: Advances in cutting edge technologies, artificial intelligence, neuromodulation, neuroethics, interventional psychiatry, and women in neuromodulation

The deep brain stimulation (DBS) Think Tank X was held on August 17-19, 2022 in Orlando FL. The session organizers and moderators were all women with the theme women in neuromodulation. Dr. Helen Mayberg from Mt. Sinai, NY was the keynote speaker. She discussed milestones and her experiences in developing depression DBS. The DBS Think Tank was founded in 2012 and provides an open platform where clinicians, engineers and researchers (from industry and academia) can freely discuss current and emerging DBS technologies as well as the logistical and ethical issues facing the field. The consensus among the DBS Think Tank X speakers was that DBS has continued to expand in scope however several indications have reached the "trough of disillusionment." DBS for depression was considered as "re-emerging" and approaching a slope of enlightenment. DBS for depression will soon re-enter clinical trials. The group estimated that globally more than 244,000 DBS devices have been implanted for neurological and neuropsychiatric disorders. This year's meeting was focused on advances in the following areas: neuromodulation in Europe, Asia, and Australia; cutting-edge technologies, closed loop DBS, DBS tele-health, neuroethics, lesion therapy, interventional psychiatry, and adaptive DBS.

The Effects of Transcranial Direct Current Stimulation in Obsessive-Compulsive Disorder Symptoms: A Meta-Analysis and Integrated Electric Fields Modeling Analysis

Transcranial direct current stimulation (tDCS) has been showing promising effects for the treatment of obsessive-compulsive disorder (OCD), but there is still no conclusion on its efficacy for this disorder. We performed a systematic review and meta-analysis of trials using tDCS for OCD and a computer modeling analysis to evaluate the electric field (EF) strengths of different electrode assemblies in brain regions of interest (ROIs) (PROSPERO-42021262465). PubMed/MEDLINE, Embase, Cochrane Library and Web of Science databases were searched from inception to 25 September 2022. Randomized controlled trials (RCTs) and open-label studies were included. The primary aim was the effect size (Hedges' g) of continuous outcomes and potential moderators of response. For EF modeling, SimNIBS software was used. Four RCTs and four open-label trials were included (n = 241). Results revealed a large effect of tDCS in the endpoint, but no significant effect between active and sham protocols. No predictor of response was found. EF analysis revealed that montages using the main electrode over the (pre)supplementary motor area with an extracephalic reference electrode might lead to stronger EFs in the predefined ROIs. Our results revealed that tDCS might be a promising intervention to treat OCD; however, larger studies are warranted.

A Case Series of Deep Transcranial Magnetic Stimulation Treatment for Patients with Obsessive-Compulsive Disorder in the Tokyo Metropolitan Area

Obsessive-compulsive disorder (OCD) is a chronic illness in which patients do not achieve remission sufficiently with conventional medication. Deep repetitive transcranial magnetic stimulation (dTMS) for OCD neuromodulates the bilateral anterior cingulate cortex (ACC) and dorsal medial prefrontal cortex (mPFC), which are known to be impaired in OCD. While dTMS treatment for OCD has shown effective results overseas, TMS treatment for OCD has rarely been implemented in Japan, and its effectiveness is unknown. We conducted an FDA-approved dTMS protocol to 26 patients with OCD. In addition, individual exposure stimulation that elicited each patient’s obsessive thoughts was also combined during dTMS treatment. Before and after 30 sessions of TMS treatment, the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was used to assess changes in the severity of each patient’s obsessive-compulsive disorder. Response to dTMS treatment in patients with OCD was determined by whether the total score on the Y-BOCS after a course of treatment was reduced by 30% or more compared with the score at baseline. The percentage of responders in this case series following the 30 sessions of dTMS treatment was 53.9%. In addition, total Y-BOCS scores and scores on each item were significantly improved. The percent changes in total Y-BOCS scores did not differ between the sexes or between on- and off-medication patients. No obvious adverse events were observed in this case series. In line with the results of TMS studies for OCD patients reported overseas, dTMS treatment for Japanese patients with OCD may have a favorable therapeutic effect.

Potentially inappropriate medications are negatively associated with functional recovery in patients with sarcopenia after stroke

BACKGROUND

Evidence is scarce for potentially inappropriate medications (PIMs) in rehabilitation medicine.

AIM

To examine the effect of PIMs on functional recovery in older patients with sarcopenia after stroke.

METHODS

We conducted a retrospective cohort study in a post-acute rehabilitation hospital. All patients diagnosed with sarcopenia aged ≥ 65 years among all post-stroke patients hospitalized from 2015 to 2020 were included. PIMs were defined based on the 2019 Beers criteria. Sarcopenia was diagnosed using handgrip strength (HG) and skeletal muscle mass index (SMI), according to the criteria of the Asian Working Group for Sarcopenia 2019. The outcomes included functional independence measure motor (FIM-motor), HG, and SMI values at discharge. Multiple linear regression analyses were used to determine whether PIMs used at admission were independently associated with outcomes.

RESULTS

Of the eligible patients, 361 were 65 years or older, of whom 196 (mean age 81.0 years, 44.4% male) presented with sarcopenia and were included in the analysis. Of these, 131 (66.8%) were prescribed PIMs at admission. The most frequently prescribed PIMs were proton pump inhibitors, antipsychotics, benzodiazepines, and nonsteroidal anti-inflammatory drugs. The number of PIMs on admission was independently associated with FIM-motor (β = - 0.132, P = 0.001) and HG (β = - 0.091, P = 0.048) at discharge, but not with SMI (β = - 0.055, P = 0.256).

CONCLUSIONS

High admission PIMs prescription numbers are negatively associated with favorable discharge functional status and muscle strength in older patients with sarcopenia after stroke.