Prolonged theta burst stimulation: A novel rTMS paradigm in neuropsychiatry

Abstract

Introduction

Repetitive transcranial magnetic stimulation (rTMS) has important role in treatment of neuropsychiatric disorders. Theta burst stimulation (TBS), a modification of rTMS, seems to produce greater changes in cortical excitability (CE) than those observed in conventional rTMS protocols. TBS is used in different protocols: intermittent TBS (iTBS) and continuous TBS (cTBS). While iTBS facilitates CE, cTBS leads to CE inhibition. However, a prolonged cTBS produces facilitatory effect similar to that of iTBS. Prolonged TBS (pTBS), a novel rTMS paradigm, is of great clinical interest for its short duration, but also because it may induce stronger effect.

Aim

To prove the effect of pTBS of motor cortex on changes of motor threshold (MT), CE and pain threshold (PT) in healthy volunteers (HV). To compare the effects of two different forms of active pTBS (pcTBS, piTBS) with placebo.

Methods

A double-blind, placebo-controlled, cross-over study compared the effects of different pTBS of contralateral M1 area on MT, CE and PT. We enrolled 24 HV to the study, who underwent all types of pTBS in randomized order and were assessed before and after each pTBS application. We used MagPro R30 (with coil focused to contralateral M1 area, 1200 pulses/session, 90% MT).

Results

A significant changes in CE and MT were found after application of continuous pTBS. Intermittent and placebo pTBS did not confirm the effect. There were no significant changes on PT after pTBS. Continuous pTBS was better tolerated than intermittent pTBS.

Conclusion

pTBS should be considered as an effective and safe treatment option for neuropsychiatric disorders.

Disclosure of interest

Supported by AZV 16-31380A.