Augmentation Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation Over Presupplementary Motor Area in Obsessive-Compulsive Disorder

Abstract

Low-frequency rTMS over pre-SMA may not be effective as an augmenting agent in partial/poor responders to SRIs. This study underlines the need to explore alternate rTMS protocols in OCD.

Continuous theta burst stimulation over the supplementary motor area in refractory obsessive-compulsive disorder treatment: A randomized sham-controlled trial

“…Chistyakov et al used 1200 to 3600 pulses per session (600 pulses repeated and separated by a 15 min interval) and found a greater effect for the 3600 pulse (28). In the same way, other studies used a greater number of pulses (1200 to 1500) than we did (11)(12)(13)(14)(15)22). In our study, 600 pulses may not have been sufficient for inducing clinical effects.…”

“…In 2006, Mantovani et al (10) demonstrated that inhibition of the SMA successfully reduced OCD symptoms. Following this pioneering study, 5 randomized trials in OCD using low frequency rTMS over the SMA (11)(12)(13)(14)(15) reported inconsistent results. In the current trial, we used cTBS, known to induce larger and longer-lasting modulation of cortical excitability than standard rTMS (16), thus offering the promise of a potentially greater clinical efficacy.…”

“…According to Rehn et al's meta-analysis (6) the SMA is the most relevant cortical target for brain stimulation in OCD patients. To date, five randomized, sham-controlled studies using repeated low-frequency (1Hz) stimulation of the SMA in treatment resistant OCD (11)(12)(13)(14)(15) have been reported. In these prior studies, low frequency rTMS applied over the SMA showed varying rates of clinical effectiveness.…”

Clinical advances in obsessive-compulsive disorder: a position statement by the International College of Obsessive-Compulsive Spectrum Disorders

“…A recent trial demonstrated superior efficacy of this protocol over antipsychotic augmentation in treatment-resistant OCD subjects (Pallanti et al, 2016). However, given recent inconsistent reports on inhibitory rTMS protocols targeting the SMA (Arumugham et al, 2018;Harika-Germaneau et al, 2019;Pelissolo et al, 2016), there is a need for large multicentre trials to confirm its efficacy at this location.…”

Noninvasive brain stimulation in obsessive–compulsive disorder

“…[14] However, an RCT from our center involving 36 patients with refractory OCD failed to demonstrate any significant difference between active and sham low-frequency rTMS over bilateral pre-SMA. [15]…”