LAUSR

Chronic insomnia is a disorder associated with increased cognitive arousal. Insomnia is also associated with activation/connectivity within the default mode network (DMN) of the brain, consistent with the hyperarousal theory. We hypothesized that suppression of the DMN with a type of repetitive transcranial magnetic stimulation (rTMS) known as continuous theta burst stimulation (cTBS) would lead to improved overnight sleep. Twenty participants (12 female; age=26.9, SD=6.6 years) meeting criteria for insomnia/sleep disorder completed a counterbalanced sham-controlled crossover study in which they served as their own controls on two separate nights of in-laboratory polysomnography (PSG) monitored sleep. In-lab visits occurred on separate weeks at least 5 days apart. Sessions included two resting state functional magnetic resonance imaging (fMRI) sessions separated by a brief 40 second cTBS rTMS session applied over an easily accessible cortical surface node of the DMN located at the left inferior parietal lobe. After scanning/stimulation, participants were allowed an 8-hour sleep opportunity from 2300 to 0700 monitored with PSG. One session of active cTBS significantly altered functional connectivity (p<.05, FDR corrected) within the DMN, while the sham condition produced no changes in functional connectivity from pre- to post-treatment. After controlling for age and IQ, active treatment was associated with significant (p<.05) improvements in PSG measured Total Sleep Time (TST; ηp2=.28), latency to Slow Wave Sleep (SWS; ηp2=.23), Sleep Efficiency (SE; ηp2=.28), and a lower Arousal Index (ηp2=.22). Overall, individuals obtained 16 minutes more sleep after active cTBS compared to sham. Moreover, changes in brain connectivity following cTBS significantly (p<.05) predicted sleep outcomes, including TST, sleep latency, SE, minutes of wake, SWS, number of awakenings, arousals, and arousal index, and a trend toward increased REM (p=.06). A brief targeted 40-second stimulation with cTBS altered DMN brain functioning, and improved PSG measured sleep outcomes during the night following stimulation. The effect sizes often exceeded those reported for other established treatments such as cognitive behavioral therapy for insomnia or hypnotic sleep medications. Further work involving multiple stimulations over several days or weeks will be necessary to demonstrate the potential utility of this approach as a treatment for insomnia. W81XWH2010173