Transcranial Magnetic Stimulation (TMS) is a Food and Drug Administration (FDA) approved treatment that induces neuronal activity in the left dorsolateral prefrontal cortex. TMS was initially developed to treat major depression after studies of patients with depression revealed hypometabolism in this brain region. Since it was first FDA approved in 2008, several types of TMS have been developed and its clinical indications expanded. Given the dearth of literature guiding clinicians in understanding different forms of TMS and their protocols, this poster will review the common and unique aspects of several forms of TMS in an effort to aid clinicians in appropriately utilizing this safe and effective neuromodulatory treatment.

Specific keywords were used to conduct a thorough but nonsystematic review of multiple databases, including PubMed, Google Scholar, and PsychInfo. Articles describing protocols rather than direct comparisons were selected. The outcomes regarding protocol guidelines, advantages, disadvantages, safety, and side effects were included in the review.

The FDA approved types of TMS include repetitive TMS (rTMS), deep TMS (dTMS), intermittent theta burst stimulation (iTBS), and accelerated TMS (aTMS). While rTMS is limited to cortical tissue, other forms of TMS reach subcortical neurons with aTMS using functional magnetic resonance imaging (fMRI) to specifically locate the target area. dTMS was approved in 2013 and its session time is half that of rTMS. Subsequently developed TMS types have even shorter sessions; iTBS sessions are only 3 minutes and aTMS is 9 minutes per session. Most TMS protocols require 8-9 weeks for full treatment, but aTMS only needs 5 days. All TMS protocols stimulate at 120% of resting motor thresholds except for aTMS which adjusts based on the patient using fMRI results. Efficacy is mostly similar with rTMS, dTMS, and iTBS demonstrating remission rates up to 30%, but aTMS had remission rates up to 90.5%. aTMS can also be used for suicidality, patients with severe or refractory depression, as well as those with comorbid anxiety, which have historically shown lower rates of success with other treatments. Overall, all forms of TMS produce minimal and temporary side effects with patients being able to return to normal activities the same day as treatment, although aTMS may cause side effects of greater intensity resulting in sleep dysregulation. Cost remains a barrier, with many insurances covering rTMS but not iTBS or aTMS.

TMS is an evidence based, efficacious, and safe treatment for depression. Most FDA-approved TMS protocols for depression have similar number of sessions, duration of treatment, common side effects, and remission rates, besides aTMS, which has dramatically greater remission rates and shorter treatment duration, making it a potentially rapid and effective treatment modality for acute and more severe cases of depression.

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