Association of Obstructive Sleep Apnea with Episodic Memory and Cerebral Microvascular Pathology: A Preliminary Study

Abstract

Objectives Evaluate the impact of obstructive sleep apnea (OSA) on neurocognitive function and brain morphology in older adults with depression and cognitive impairment. Methods We prospectively screened OSA with the STOP-Bang questionnaire in the last 25 patients enrolled into the Donepezil Treatment of Cognitive Impairment and Depression (DOTCODE) trial. High and low probability of OSA were defined as a STOP-Bang score of ≥5 (h-OSA) and of <5 (l-OSA). Baseline MRI was used to evaluate brain morphology. The initial 16 weeks of antidepressant treatment were part of the DOTCODE trial. Results After 16 weeks of antidepressant treatment, the h-OSA group performed significantly worse on the Selective Reminding Test (SRT) delayed recall task than the l-OSA group, controlling for baseline performance (F=19.1, df=1,22, p<0.001). In nineteen out of 25 participants who underwent brain MRI, the h-OSA group had significantly greater volumes of MRI hyperintensities in deep white matter, periventricular white matter, and subcortical gray matter compared to the l-OSA group. There was no significant association between OSA and hippocampal or entorhinal cortex volumes in our sample, even after controlling for intracranial volume. Conclusions OSA is associated with impaired verbal episodic memory and microvascular damage in older adults with depression and cognitive impairment. One possibility is that by contributing to cerebral microvascular damage, OSA may exacerbate progressive memory decline.

Sex-specific hippocampus volume changes in obstructive sleep apnea

“…OSA is associated with AD pathophysiology, including amyloid burden and atherosclerosis ( Polsek et al, 2018 ; Lutsey et al, 2018 ; Sharma et al, 2018 ), and there is some evidence sleep-disordered breathing precipitates dementia ( Lutsey et al, 2018 ; Osorio et al, 2015 ; Emamian et al, 2016 ). Additionally, brain changes in OSA impact structures that are associated with AD-related cognitive decline ( Lutsey et al, 2016 ; Kerner et al, 2017 ), and the hippocampal changes shown here are another such finding. An intriguing possibility raised by the sex differences in OSA-related hippocampus volume changes is that the sleep disorder confers different risks for AD in females and males, a possibility raised over 30 years ago ( Smallwood et al, 1983 ).…”

The relationship between inflammation and neurocognitive dysfunction in obstructive sleep apnea syndrome

“…Additionally, many studies have suggested that sustained attention deficits in OSAS patients are positively associated with motor vehicle accident risk [96,97]. The data provided by several studies revealed significant deficits in verbal but not visual memory [98][99][100]. A metaanalysis specifically focusing on memory problems in OSAS patients demonstrated significant impairments in immediate and delayed verbal and visuospatial memory and immediate visual recall [101].…”

Sleep as a Therapeutic Target in the Aging Brain

“…OSA is highly prevalent in the middle-aged population and worsens with age. It is characterized by repetitive transient upper airway obstructions during sleep that result in either complete (apnea) or partial (hypopnea) pauses in breathing [99][100][101][102]. Periods of apnea are accompanied by periods of hypoxemia and by brief electroencephalographic and autonomic arousals that lead to a disruption of normal sleep architecture [101].…”