Transcranial direct current stimulation in obsessive-compulsive disorder: an update in electric field modeling and investigations for optimal electrode montage

ABSTRACT

Introduction: Transcranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation intervention that has been investigated for several psychiatric disorders, including Obsessive-Compulsive Disorder (OCD). As there are several candidate brain regions for targeting OCD relevant networks, clinical studies using tDCS have considerably varied in terms of the electrode montages used. Computer modeling of electric field currents induced by tDCS can help guiding the research of relevant targets for OCD. In this review, the authors used this tool to investigate targeted brain areas from previous studies of tDCS in OCD.

Areas covered: A literature search for articles with the keywords ‘tDCS’, ‘Transcranial Direct Current Stimulation’ and ‘Obsessive Compulsive Disorder’ was conducted to identify relevant publications. For comparing different electrode montages, electric field (EF) models were performed using high-resolution brain scan templates. Authors found 13 studies mostly showing an improvement in OCD symptoms. The electrode montages varied considerably between studies. Nonetheless, two main patterns of EFs could be identified: ‘focal montages’, with EFs concentrated in the prefrontal cortex, and ‘diffuse montages’, with widespread EFs over cortical areas.

Expert opinion: Electric field simulation can guide future clinical trials in psychiatry, using personalized tDCS montages with distinct electrode positioning according to clusters of symptoms

KEYWORDS:

• Obsessive-compulsive disorder
• tDCS
• neuromodulation
• electric field
• computer modeling

Article highlights

• tDCS is a non-invasive neuromodulatory intervention that has been studied for neuropsychiatric disorders.

• OCD is a neuropsychiatric disorder where up to one third of patients fail to respond adequately to first-line therapies.

• There is little evidence for using tDCS in OCD, with only a few case reports and clinical trials published. These studies have considerably varied in terms of electrode montages used and brain regions targeted.

• The authors identified two categories of stimuli: montages with the EFs focused on different PFC regions and montages with more diffuse EFs in large cortical areas across different brain regions (including the PFC).

• Computer simulations could estimate the spatial distribution of the electrical fields and be useful to define montages do ameliorate OCD symptoms.

• This box summarizes key points contained in the article.

Declaration of interest

MC Batistuzzo has received financial support from Sao Paulo Research Foundation (FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo grant #2016/05865-8). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or conflict with the subject matter or materials discussed in this manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.