Obstructive sleep apnea (OSA) is recurrent episodes of partial or complete obstruction of the upper airway during sleep that causes intermittent hypoxia and sleep fragmentation and leads to cardiometabolic and neurocognitive sequelae. Chronic intermittent hypoxia, sleep fragmentation of OSA, and insufficient sleep have been significantly associated with higher risks of neurocognitive impairment, including mild cognitive impairment (MCI) and Alzheimer's disease. Thus, sleep and circadian function might be modifiable neurocognitive impairment factors. The significance of the study is to understand the relationships of MCI with sleep apnea and sleep-related symptoms, which helps pave the groundwork for further research.