0435 Continuous Theta-burst Stimulation Lowers the Impact of Anxiety on Sleep Duration in Individuals with Insomnia

Abstract Introduction Repetitive Transcranial Magnetic Stimulation (rTMS) is a procedure by which a magnetic coil is used to stimulate specific regions of the brain to bring about alterations in function. Continuous theta-burst stimulation (cTBS) is a form of rTMS that was used to suppress cortical excitability and lower within network connectivity in the Default Mode Network (DMN). Connectivity within the DMN is associated with rumination and mind-wandering. Prior research indicates that pre-sleep anxiety is associated with increased sleep latency and decreased sleep continuity. As part of a larger project, we hypothesized that pre-sleep anxiety would negatively impact total sleep time, as measured by polysomnography (PSG), but that this effect would be reduced or eliminated in the active cTBS condition compared to sham. Methods We administered cTBS to 20 participants with insomnia symptoms (Nmales = 8, Mage=31.6, SD=6.7) (Nfemales =12, Mage=23.8, SD=4.3). Participants then underwent one administration of sham stimulation and one administration of active cTBS to the left angular gyrus node of the DMN in a randomized order separated by one week. The State Trait Anxiety Inventory (STAI-S) was administered immediately before each session, and PSG data was collected during overnight laboratory stays following the TMS sessions. We ran two linear regressions between STAI-S scores and total sleep time - one analysis for the sham condition and another for the active condition. Results Elevated STAI-S scores (M=41.6, SD=6.984) predicted decreased total sleep time (Mean minutes=393.75, SD=48.45) for the sham cTBS condition (F(1,18)=8.689, p=.009; β=-.571, p=.009). In contrast, the relationship between STAI-S scores (M=40.9, SD=50.35) and total sleep time (Mean minutes=403.8, SD=5.34) was not significant for the active cTBS condition (F(1,18)=2.409, p=.138; β=-.344, p=.138). Conclusion Prior data presented from this trial revealed that active cTBS improved TST overall. However, here we further demonstrated that higher pre-sleep anxiety predicted a lower sleep duration for the sham cTBS condition but not for the active cTBS condition, suggesting that the active cTBS may mitigate the effects of anxiety on sleep. These findings support the applicability of continuous theta-burst stimulation in treating psychiatric conditions related to sleep difficulties, such as anxiety. Support (if any) US Army Medical Research Acquisition Activity Grant: W81XWH2010173