Transcranial magnetic stimulation in obsessive-compulsive disorder: A focus on network mechanisms and state dependence

Abstract

BackgroundTranscranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique that has shown promise as an adjunct treatment for the symptoms of Obsessive-Compulsive Disorder (OCD). Establishing a clear clinical role for TMS in the treatment of OCD is contingent upon evidence of significant efficacy and reliability in reducing symptoms.ObjectivesWe present the basic principles supporting the effects of TMS on brain activity with a focus on network-based theories of brain function. We discuss the promises and pitfalls of this technique as a means of modulating brain activity and reducing OCD symptoms.MethodsSynthesis of trends and critical perspective on the potential benefits and limitations of TMS interventions in OCD.FindingsOur critical synthesis suggests the need to better quantify the role of TMS in a clinical setting. The context in which the stimulation is performed, the neural principles supporting the effects of local stimulation on brain networks, and the heterogeneity of neuroanatomy are often overlooked in the clinical application of TMS. The lack of consideration of these factors may partly explain the variable efficacy of TMS interventions for OCD symptoms.ConclusionsResults from existing clinical studies and emerging knowledge about the effects of TMS on brain networks are encouraging but also highlight the need for further research into the use of TMS as a means of selectively normalising OCD brain network dynamics and reducing related symptoms. The combination of neuroimaging, computational modelling, and behavioural protocols known to engage brain networks affected by OCD has the potential to improve the precision and therapeutic efficacy of TMS interventions. The efficacy of this multimodal approach remains, however, to be established and its effective translation in clinical contexts presents technical and implementation challenges. Addressing these practical, scientific and technical issues is required to assess whether OCD can take its place alongside major depressive disorder as an indication for the use of TMS.

Efficacy of Intensive Cerebellar Intermittent Theta Burst Stimulation (iCiTBS) in Treatment-Resistant Schizophrenia: a Randomized Placebo-Controlled Study

“…The use of neuronavigation to target a specific cortical site rather than scalp-based localization technique can be improved upon. Moreover, biophysical models to counter optimal angle of stimulation may be used to personalize TMS delivery as suggested in other psychiatric conditions like OCD [ 48 ]. This being the first RCT of iTBS over midline cerebellum is the strength of the study.…”

Effects and Therapeutic Use of TMS in Psychiatric Disorders: An Evidence-Based Review

“…In addition, in their opinion, rTMS could be as effective as other second-or third-line pharmacological strategies for OCD with fewer metabolic adverse effects. TMS could be used to facilitate the response to medication for which dose increases for the patient are not possible [187]. TMS DLPFC during the viewing of symptom-provoking stimuli may facilitate the response to subsequent cognitive behavioral therapy [188].…”

Static and dynamic network properties of the repetitive transcranial magnetic stimulation target predict changes in emotion regulation in obsessive-compulsive disorder

“…Functional connectivity and network topological indices may offer advanced imaging-based predictors of individual response [13,18,19]. Functional connectivity refers to the statistical interdependencies between time series representing brain activity of different locations in the brain that are presumed to represent functional communication [20].…”

“…high betweenness centrality, of the target region [19]. In OCD, network topology has also been hypothesized, but not proven, to predict rTMS response [13].…”