0559 Continuous Theta Burst Stimulation and Pre-Sleep Worry

Abstract Introduction Continuous theta burst stimulation (cTBS), a type of repetitive transcranial magnetic stimulation (rTMS), has been shown to reduce the severity of insomnia and anxiety in participants with insomnia. This study examined whether pre-sleep rumination impacts sleep onset latency (SOL) and whether these effects would be ameliorated following cTBS targeted to the default mode network (DMN), a brain system involved in self-focused cognition and ruminative thinking. Methods Twenty participants (12 female, 8 male) with insomnia symptoms completed two overnight in-lab sessions including the administration of either active or sham cTBS in a counterbalanced, cross-over, double-blind clinical trial. Participants completed the Glasgow Content of Thoughts Inventory (GCTI) before and after cTBS administration, followed by eight hours of sleep in-lab monitored by polysomnography. The GCTI items assessed pre-sleep thought types (i.e., problem-solving, worries, and thoughts about sleep) and frequency. A paired samples t-test compared pre-cTBS and post-cTBS GCTI scores in the sham and active conditions. Another t-test examined SOL from sham to active cTBS. Two simple linear regressions examined the effect of the change in GCTI from pre-cTBS to post-cTBS on SOL during the sham and active visits, separately. Results There were no differences in SOL by treatment condition (p>0.05). GCTI scores post-cTBS (M=51.95, SD=10.95) were significantly higher than pre-cTBS (M=48.75, SD=10.99) in the sham condition (p=0.047); however, GCTI scores post-cTBS (M=49.85, SD=10.83) were not significantly different than pre-cTBS (M=48.20, SD=12.73) in the active condition (p=0.271). Two simple linear regressions showed that the change in GCTI from pre to post-cTBS administration had no significant effect on SOL in the sham condition (F(1,18)=3.677, B=2.154 p=0.071, R2=0.123) or active condition (F(1,18)=2.474, B=-1.593, p=0.133, R2=0.072). Conclusion There were no direct treatment-condition effects on pre-sleep rumination or SOL. However, pre-sleep rumination increased following sham cTBS only, suggesting that this increase may have been ameliorated in the active condition. However, the small sample size of this pilot study and single administration presents a limitation to statistical power. Future work should examine the effect of active cTBS for reducing pre-sleep rumination in larger clinical trials with multiple administrations. Support (if any) Army Research Office award W81XWH2010173