Patients recovering from acute COVID-19 infection often suffer from a multitude of debilitating chronic physical symptoms that can last up to 6 months or more. The incidence of fatigue, cognitive impairment and respiratory symptoms are reported to be very high in the post-COVID period. The underlying pathophysiology of cognitive impairment is unclear in these patients. Notably, sleep disturbances are common during this post-COVID period, and sleep apnea has been associated with an increased risk for severe COVID infection. Thus, it is conceivable that sleep fragmentation, per se, may confer an increased risk for chronic cognitive deficits in Veterans post-COVID. Our proposed pilot project will determine if there is a link between post-COVID sleep disturbances, sleep apnea and cognitive function. Knowledge gained from our examinations may guide development of novel management pathways, i.e., mitigation of sleep disturbances may present a therapeutic strategy for alleviating chronic post-COVID cognitive impairment. Aim1 will investigate the effect of sleep duration and sleep quality on neurocognitive function in post-COVID Veterans. Aim 2 will study whether the severity of OSA determines neurocognitive function Veterans who are post-COVID. This is an observational study where we will gather retrospective as well as prospective data on the long-term effects of COVID on neurocognitive function and sleep. Our long-term goal is to enhance rehabilitation and recovery of function of Veterans suffering from post-COVID consequences that may arise due to sleep disturbances, with the ultimate objective of improving the overall health and quality of life of Veterans recovering from COVID-19 infection.