Intermittent Versus Continuous Theta Burst Stimulation for Psychomotor Symptom Attenuation in Parkinsonism: A Meta-Analysis of Reviewed Literature

Background: Approximately 1-3% of the population is affected by obsessive-compulsive disorder (OCD) over their lifetime.Current treatment interventions include pharmacotherapy, psychotherapy, exposure and response prevention, and repetitive transcranial magnetic stimulation (rTMS).There are currently 3 FDA-cleared devices for the treatment of OCD: the Brainsway Deep TMS system and H7 coil, the D-B80 coil, and the figure-8 coil.Methods: We conducted a systematic literature review to investigate studies comparing two or more rTMS frequencies across psychiatric, neurologic, and healthy domains.Each article was screened against the inclusion and exclusion criteria and assessed using the Mixed Methods Appraisal Tool by two independent reviewers.The following data were extracted from each article: disease state, participant demographic data, stimulation parameters, outcome measures, tolerability and safety outcomes, dropout rate, and pharmacotherapy, if applicable.Results: Of the 129 included studies, 2 studies examined OCD, and 1 study examined compulsive behavior disorders.Each study delivered treatment to a different target: the right dorsolateral prefrontal cortex, left orbitofrontal cortex/frontopolar cortex, and right pre-supplementary motor area.Though treatment targets varied, inhibitory stimulation (1 Hz and cTBS) improved symptoms of OCD, whereas excitatory stimulation (10 Hz and iTBS) had minimal or short-term effects.Discussion: Despite the growing clinical use of TMS as a treatment for OCD, only 3 studies directly compare stimulation frequencies.This lack of evidence prevents firm conclusions from being made on optimal stimulation parameters for the treatment of OCD and related disorders and underscores the need for systematic, head-to-head trials to guide clinical protocol selection.