Due to Covid 19 pandemic emergency measures, recruitment for clinical trials is currently on hold~Background: Sleep apnea is one of the most common chronic condition among US military Veterans , it causes sleepiness, reduced psychomotor vigilance and depression, which undermine daytime functioning and quality of life . Persistent daytime symptoms of sleepiness and depression in individuals with OSA who are using Continuous Positive Airway Pressure (CPAP) are associated with adverse long term medical and functional outcomes . Current treatment options are limited to stimulants and modafinil, whose long-term safety profile, effectiveness and impact on functional recovery is largely unknown. The mechanisms for residual daytime symptoms in CPAP-treated sleep apnea are poorly understood and very little attention has been placed on interplay between sleep apnea and the circadian system. Notably, sleepiness, fatigue and depression, cardinal symptoms of OSA syndrome, are common manifestations of circadian misalignment. Circadian rhythms are synchronized to the environmental light or dark and to social activity cycles by zeitgebers (time givers) .Preliminary studies in humans and animal models have shown persisting alterations of circadian rhythms in OSA patients, that fail to normalize with CPAP treatment. CPAP treatment, while effective at correcting respiratory events and night time blood oxygen saturation levels, does not necessarily re-align the circadian system. Supplementary exposure to bright light has beneficial effects on sleep quality and daytime vigilance in healthy individuals and it has been increasingly applied in a variety of sleep and neuropsychiatric conditions. However, no study to date has tested the application of BLT to treat daytime symptoms associated with sleep apnea. The investigators' study will be the first to explore the role of Bright Light Therapy (BLT), a well-established non-pharmacological intervention for circadian disturbances, for the treatment of residual daytime symptoms of OSA which do not respond to CPAP.
Sleep apnea is one of the most common chronic condition among US military Veterans, causing sleepiness, reduced psychomotor vigilance and depression, which undermine daytime functioning and quality of life. Persistent daytime symptoms of sleepiness in individuals with Obstructive Sleep Apnea (OSA) who are using Continuous Positive Airway Pressure (CPAP) are associated with adverse long term medical and functional outcomes. Residual daytime sleepiness (RDS) is associated with reduced occupational and family functioning and overall lower quality of life. Napping is a common behavior among individuals with OSA and RDS and has been linked to both benefits to and decline in health and functioning. Longer nap times may maintain, as opposed to decrease, sleepiness by promoting sleep inertia and can contribute to maintaining subclinical circadian alterations that result in higher night-tonight variability in sleep patterns. Preliminary studies in humans and animal models have shown persisting alterations of circadian rhythms in OSA patients, that fail to normalize with CPAP treatment. CPAP treatment, while effective at correcting respiratory events and night time blood oxygen saturation levels, does not necessarily re-align the circadian system. Current treatment options are limited to stimulants and modafinil, whose long-term safety profile, effectiveness and impact on functional recovery is largely unknown. Supplementary exposure to bright light has beneficial effects on sleep quality and daytime vigilance in healthy individuals and it has been increasingly applied in a variety of sleep and neuropsychiatric conditions. However, no study to date has tested the application of BLT to treat daytime symptoms associated with sleep apnea. The investigators' study will be the first to explore the role of Bright Light Therapy (BLT), a well-established non-pharmacological intervention for circadian disturbances, for the treatment of residual daytime symptoms of OSA which do not respond to CPAP.