0416 Preliminary Study of the Effects of Continuous Theta Burst Stimulation of the Default Mode Network on Subjective Sleepiness

Abstract Introduction Repetitive transcranial Magnetic Stimulation (rTMS) is a noninvasive intervention commonly used to treat clinical depression by modulating brain activity in specific regions. We investigated rTMS of the default mode network (DMN) as a potential treatment for insomnia. The DMN is associated with internally focused cognition and rumination. Therefore, we expected that modulation of this network would improve sleep. As reported elsewhere, this trial showed that active cTBS to the DMN improved polysomnographically (PSG) measured sleep. Here, we hypothesized that participants who were treated with active continuous theta burst stimulation (cTBS) rTMS over the DMN versus sham cTBS would report reduced subjective sleepiness following post-treatment sleep. Methods Twenty adults with clinical insomnia completed this study (Mage=26.90, SD=6.56). Participants completed two overnight visits; one where they received active cTBS treatment and one where they received sham TMS treatment. We analyzed the Karolinska Sleepiness Scale (KSS), which was administered six times throughout each visit. KSS 1-3 were administered prior to treatment and KSS 4-6 were post TMS treatment. We used a repeated measures ANOVA to analyze effects of TMS on reported daytime sleepiness. Results There was no main effect of condition on sleepiness score F(1,18 )=1.165, p=0.295, ηp 2=0.061. There was a significant interaction effect of condition and pre/post intervention on reported subjective sleepiness F(1,18)=3.079, p=0.013, ηp 2 = 0.146, although follow-up analyses did not reveal significant differences. Nonetheless, there was a continuous negative trend toward reduced sleepiness for post TMS administration after overnight sleep in active cTBS (M = 4.8, SD = 1.96) compared to the sham cTBS session (M = 5.2, SD = 1.91) (p = 0.366). Conclusion As reported elsewhere, this trial of a single administration of cTBS showed improved PSG sleep. Here we saw that there was no significant change in subjective sleepiness following a night of sleep with or without the trial of cTBS, but there was a nonsignificant trend toward declining sleepiness for the active cTBS group relative to the sham condition. This preliminary study is encouraging and suggests that further research into this approach is warranted. Support (if any) W81XWH2010173