Priming in Repetitive Transcranial Magnetic Stimulation in the Treatment of Obsessive Compulsive Disorder

Priming in Repetitive Transcranial Magnetic Stimulation in the Treatment of Obsessive Compulsive Disorder

Priming in Repetitive Transcranial Magnetic Stimulation (TMSr) in the Adjuvant Treatment of Obsessive Compulsive Disorder (OCD)

Obsessive Compulsive Disorder results in high social impact, affecting quality of life and tending to a chronic course. A considerable proportion of patients, up tp 60%, remain with symptoms even thought treatment is administrated. Therefore, new therapeutic interventions are highly necessary. In this context, repetitive transcranial magnetic stimulation has been used for several psychiatric conditions, including OCD treatment. Moreover, many approaches of neuromodulation seem to reach a better result when used a priming stimulation. In an attemp to optimize particularities of the thecnique applied, this study aims to assess if a priming stimulation with rTMS might impact in a better outcome when compared with rTMS without previous stimulation.

This is a randomized, double-blind, sham-controlled clinical trial. Neuropsychological tests and a sociodemographic and clinical questionnaire will be used to assess and characterize the subjects. Participants captured by the Laboratory of Studies in Aging and Neuroscience at the Federal University of Paraíba will be divided into 02 groups, each with 16 patients, totaling 50 volunteers: Active - participants who will receive real priming stimulation; Sham - participants who will receive simulated priming stimulation. Participants entered through the eligibility criteria will be randomly allocated in a simple way, at a rate of 1:1. In the active priming, the parameters are: frequency of 6 Hz for 10 minutos, 80% do Motor Threshold (MT), 20 trains of 5 seconds, with intertrain interval of 25 seconds, a total f 600 stimulations. The group of innactive priming will have the same parameters, but without active atimulation. After this previous stimulation, all participants will receive the main stimulation: 10 sessions of rTMS, each lasting around 20 minutes, for 5 days a week, during two consecutive weeks. The target area will be the supplementary motor area. Primary outcome will be assessed by change in Yale-Brown Obsessive Compulsive Scale scores. As secondary outcomes, it will be used HAM-A for anxiety, HAM-D for depression, CGI-S for global clinical impression and SF-36 for quality of life.

Parallel Assignment Participants will be divided into 02 groups, each with 16 patients, totaling 32 volunteers: Active - participants who will receive real priming stimulation; Sham - participants who will receive simulated priming stimulation. Participants entered into the study through the eligibility criteria will be randomly allocated in a simple way, at a rate of 1:1.

Duble (Participant, Investigator) All examiners will be blinded to the type of treatment the patient received (active stimulation or sham) and other assessments. Thus, all guidelines established by CONSORT 2010 (Consolidated Standards of Reporting Trials) will be complied with variable control following systematized and countersigned procedures: random sequence generation, allocation concealment, blinding of participants and professionals, blinding of outcome evaluators and attrition bias (loss analysis using the last observation carried forward method)

To apply intervention, it will be used Repetitive Transcranial Magnetic Stimulation Model MagPro R20 (MagVenture Brazil, country Brazil) and the butterfly coil MCF-B70 (MagVenture Brazil, country Brazil). Each session will last around 20 minutes, and it will be used a 1 Hz frequency, 1200 pulses/day, with 100% of Motor Threshold, once a day, 5 days a week, for two consecutive weeks. Active Priming group participants will be previously stimulated for 10 minutes (20 trains of 5 seconds with intertrain interval of 25 seconds), with 6Hz frequency over Supplementary Motor Area, receiving 80% of Motor Threshold, with a total of 600 stimulations.

Sham Priming group participants will receive a placebo stimulation for ten minutes, with the same parameters and target area as the active group, they will hear the equipament noise and might feel any sensation in the scalp, but there won't be effective stimulation.

It will be applied an active priming stimulation in the supplementary motor area previously to the main stimulation to analyse if that will enhance the response to TMSr, compared to inactive priming. To apply intervention, it will be used Repetitive Transcranial Magnetic Stimulation Model MagPro R20 (MagVenture Brazil, country Brazil) and the butterfly coil MCF-B70 (MagVenture Brazil, country Brazil). Each session will last around 20 minutes, and it will be used a 1 Hz frequency, 1200 pulses/day, with 100% of Motor Threshold, once a day, 5 days a week, for two consecutive weeks. Active Priming group participants will be previously stimulated for 10 minutes (20 trains of 5 seconds with intertrain interval of 25 seconds), with 6Hz frequency over Supplementary Motor Area, receiving 80% of Motor Threshold, with a total of 600 stimulations.

Sham Priming group participants will receive a placebo stimulation for ten minutes, with the same parameters and target area as the active group, they will hear the equipament noise and might feel any sensation in the scalp, but there won't be effective stimulation.

It's a 10-item-scale that evaluates the symptoms' severity of Obsessive Compulsive Disorder. Includes five dimensions that evaluate obsessions and compulsions. The ten itens score from 0 (no symptom) to 4 (extreme symptoms), possibly scoring from 0-20 in obsessions' severity, 0-20 in compulsions' severity, with a total 0-40. YBOCS is considered gold standard in evaluating the severity of OCD symptoms.

It's a multidimensional scale which allows evaluating depression symptoms. It will be chosen the variant of 17-item, given that the 21-item doesn't add relevant information for our purposes.

It's divided into two sub-scales, one that evaluates the severity of disease and one that evaluates clinical improvements. Scores from 1 to 7 (in which 7 refers to worse severity or worse improvement).

Inclusion Criteria: Being right-handed; Age between 18 and 60; Diagnose of OCD according to DSM-5; Score in YBOCS between 16 and 23; No change in dose prescription in the previous 3 months; Signature of informed consent term. Exclusion Criteria: Being pregnant; Having cognitive deficit; Diagnose of drug use disorder; In current psychotherapy (or interrupted in less than 3 months); Diagnose of severe Major Depression; Risk of suicide; Patients with metallic implants in the brain; Epileptics.