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Background: Obstructive sleep apnea (OSA) is associated with an increased risk of amyloid-β (Aβ) burden, the hallmark of Alzheimer's disease, and cognitive decline. Objective: To determine the differential impacts of hypoxemia and slow-wave sleep disruption on brain amyloid burden, and to explore the effects of hypoxemia, slow-wave sleep disruption, and amyloid burden on cognition in individuals with and without OSA. Methods: Thirty-four individuals with confirmed OSA (mean±SD age 57.5±4.1 years; 19 males) and 12 healthy controls (58.5±4.2 years; 6 males) underwent a clinical polysomnogram, a NAV4694 positron emission tomography (PET) scan for Aβ burden, assessment of APOEɛ status and cognitive assessments. Linear hierarchical regressions were conducted to determine the contributions of demographic and sleep variables on amyloid burden and cognition. Results: Aβ burden was associated with nocturnal hypoxemia, and impaired verbal episodic memory, autobiographical memory and set shifting. Hypoxemia was correlated with impaired autobiographical memory, and only set shifting performance remained significantly associated with Aβ burden when controlling for sleep variables. Conclusions: Nocturnal hypoxemia was related to brain Aβ burden in this sample of OSA participants. Aβ burden and hypoxemia had differential impacts on cognition. This study reveals aspects of sleep disturbance in OSA that are most strongly associated with brain Aβ burden and poor cognition, which are markers of early Alzheimer's disease. These findings add weight to the possibility that hypoxemia may be causally related to the development of dementia; however, whether it may be a therapeutic target for dementia prevention in OSA is yet to be determined. [ABSTRACT FROM AUTHOR]

Objectives: Autobiographical memory dysfunction is a marker of vulnerability to depression. Patients with obstructive sleep apnea (OSA) experience high rates of depression and memory impairment, and autobiographical memory impairments have been observed compared to healthy controls; however, these groups were not age-matched. This study aimed to determine whether individuals with untreated OSA have impaired autobiographical memory when compared to age-matched controls, and to assess the quality of autobiographical memories from three broad time points. Methods: A total of 44 participants with OSA (M age=49.4±13.0) and 44 age-matched controls (M age=50.0±13.1) completed the Autobiographical Memory Interview (AMI) to assess semantic and episodic memories from three different life stages, and 44 OSA participants and 37 controls completed the Autobiographical Memory Test (AMT) to assess overgeneral memory recall (an inability to retrieve specific memories). Results: OSA participants had significantly poorer semantic recall of early adult life on the AMI (p <.001), and more overgeneral autobiographical memories recalled on the AMT (=.001), than controls. Poor semantic recall from early adult life was significantly correlated with more depressive symptoms (p =0.006) and lower education (p <0.02), while higher overgeneral memory recall was significantly associated with older age (p =.001). Conclusions: A specific deficit in semantic autobiographical recall was observed in individuals with OSA. OSA patients recalled more overgeneral memories, suggesting that aspects of the sleep disorder affect their ability to recollect specific details of events from their life. These cognitive features of OSA may contribute to the high incidence of depression in this population. (JINS 2019, 25 , 266–274) [ABSTRACT FROM AUTHOR]