Assessing Sleep Spindle and Slow Wave Alterations and Their Relationships with Clinical Symptoms in Individuals with Early-Course Schizophrenia Using Ambulatory EEG and Digital Monitoring

About This Grant

Project Summary Schizophrenia (SCZ) is a severe psychiatric disorder that greatly impacts affected individuals, especially in its early stages. Sleep disturbances, assessed with sleep questionnaires, are commonly reported by individuals with SCZ, and in-laboratory sleep studies have established deficits in two sleep-specific EEG oscillatory rhythms - sleep spindles (brief bursts of 12-16 Hz activity) and slow waves (large amplitude ~1 Hz oscillations) - in SCZ. However, the persistence of sleep oscillatory deficits and their presence in the natural environment of individuals with SCZ have yet to be assessed. To address these gaps, the proposed study aims to provide longitudinal, ambulatory assessments of spindle and slow wave deficits in individuals with early- course SCZ (EC-SCZ) vs. healthy control (HC) subjects using portable EEG. Recent technological advancements enable frequent data collection of sleep disturbances and clinical symptoms (e.g., with daily diary assessment) in clinical populations, including individuals with SCZ in their home environments. Recent evidence shows that poorer sleep quality predicts worsening psychotic symptoms and relapse in SCZ. In SCZ patients, sleep spindle deficits have been associated with negative symptoms, while slow wave abnormalities are more closely linked to their positive symptoms. The proposed study will collect daily digital measurements of sleep quality and clinical measures to investigate the relationships between 1) EEG measures of sleep oscillations and clinical symptoms, and 2) daily self-reported sleep quality and clinical symptoms in individuals with EC-SCZ. To achieve these goals, we will perform longitudinal ambulatory sleep EEG assessments at 2- week, 14-week, and 26-week time points in twenty-five individuals with EC-SCZ and twenty-five HC subjects, with two consecutive nights of recording per time point and Fitbit monitoring for one week before each assessment. Participants will complete sleep apnea screening, and EEG assessment will be repeated if sleep parameters deviate significantly from typical patterns established through Fitbit data. Additionally, the participants with EC-SCZ will complete daily digital self-report measures (i.e., validated, adapted versions of Pittsburgh Sleep Quality Index [PSQI], Positive and Negative Syndrome Scale [PANSS], Generalized Anxiety Disorder scale-2 [GAD-2], and Patient Health Questionnaire-2 [PHQ-2]) for three 29-day blocks, each centered around a sleep EEG assessment; each block will be separated by four weeks of no data collection. Findings may establish the feasibility and validity of ambulatory sleep and clinical assessments in EC-SCZ and pave the way for novel, early interventions based on sleep neurophysiology.