Grant: DRA : Canada Graduate Research Scholarship - Doctoral Program (CGRS D)

Background: Many patients with depression experience sleep problems, which can make their symptoms worse and harder to treat. Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment option for patients with depression that do not respond to antidepressant medications. Recently, studies have found that patients often experience better sleep quality after rTMS treatments. However, very few studies have examined how rTMS impacts physiological measures of sleep, including brain activity during the night. Understanding these changes could help scientists to fine-tune treatments to maximize their effects on both sleep and depression symptoms. We will examine whether rTMS causes changes in sleep such as: (1) increases in slow-wave brain activity in prefrontal regions, which may suggest patients are getting deeper sleep; (2) increases in sleep spindle density, which plays an important role in maintaining sleep; (3) decreases in prefrontal brain activity in the alpha band, which may reflect decreased arousal during the night; (4) changes in rapid eye movement sleep, which often begins earlier and lasts longer in people with depression. We will then examine whether changes in sleeping brain activity are related to improvements in clinical symptoms, including depression and perceived sleep quality. Methods: Participants will be randomly assigned to receive unilateral or bilateral rTMS for 4-6 weeks. They will complete weekly at-home sleep recordings using a wearable headband device, which will record brain activity during the night. Sleep quality and depression will be assessed with the Leeds Sleep Evaluation Questionnaire and Hamilton Rating Scale for Depression. Significance: This study will provide insight into the nature and timing of rTMS-related changes in sleep, and how they relate to changes in depression. This could help identify factors that predict response to rTMS, which may be used to determine who will benefit most from these treatments.