Enhancing Slow Wave Sleep in Depression

The purpose of this pilot study is to determine if non-invasive transcranial electrical stimulation (TES) delivered during slow-wave sleep (SWS) can enhance this stage of sleep in people with depression. Individuals with depression frequently report sleep and cognitive disturbances as symptoms associated with their depression. However, common anti-depressants often fail to improve these symptoms. A pilot study with this device showed that TES can enhance slow wave sleep in healthy individuals. This study aims to evaluate if TES will enhance deep sleep in individuals with depression as well, leading to improved sleep outcomes and potentially improving cognitive performance and mood symptoms. This study proposes to conduct using the Sleep WISP device (Brain Electrophysiology Laboratory (BEL), Eugene, OR). Using this non-invasive device, the study will record brain activity using a technique called electroencephalography (EEG) that will be automatically scored in real-time to determine the stage of sleep. After the participant enters stable slow wave sleep, the headband will deliver the TES current (0.5-1 milliampere (mA) total) directly to the scalp through pre-set electrodes. The stimulation will be applied for 5 cycles of 5 minutes of stimulation, 1 minute of no stimulation (30 minutes total). This level and location of stimulation was previously shown as sufficient to increase SWS. After screening and enrolling in the study, participants will have up to three nights of baseline recordings using the WISP headband to ensure successful baseline measurements are recorded. Participants will then receive TES nightly for two weeks. Participants will also wear an actigraphy watch and keep a sleep diary throughout the duration of the study. Finally, participants will complete several cognitive assessments and sleep and mood questionnaires throughout the duration of the study.