Is Obstructive Sleep Apnoea Related to Neuropsychological Function in Healthy Older Adults? A Systematic Review and Meta-Analysis

Abstract

Previous systematic reviews and meta-analyses have identified cognitive deficits in adults with obstructive sleep apnoea (OSA). However, quantitative analysis of the association between OSA and neuropsychological performance has not been conducted specifically in older adults, for whom there is a greater risk of cognitive decline. We searched Medline, Embase and PsycINFO through August 2016 for studies describing associations between OSA and neuropsychological outcomes in people aged>50 years. Meta-analyses were performed on these studies for overall cognition and within cognitive domains. Subgroup analyses were performed taking into account risk of bias and moderating differences in study design. 13 studies met eligibility criteria for analysis. A small negative association was found between OSA and all neuropsychological outcomes combined, g=0.18(95% CI 0.04-0.32), and in memory and processing speed domains. Small case-control studies from sleep clinic populations observed the greatest associations, while larger cohort studies from community samples illustrated no association. Analysis accounting for publication bias resulted in a null overall association, g=0.02 (95%CI -0.12 to 0.16). Associations between OSA and cognition in later life are highly variable and the findings differ based on the type and setting of study. It appears some older adults may be at risk of cognitive impairments attributable to OSA; however, the risk of bias renders the evidence inconclusive. High quality research is warranted in clinically diagnosed OSA patients as well as those already experiencing neuropsychological impairment and who may be regarded at higher risk of further cognitive decline.

Obstructive Sleep Apnea and the Risk of Cognitive Decline in Older Adults

“…However, a study using the PROOF-SYNAPSE cohort showed only small longitudinal changes in selected cognitive functions (11). This weak link between OSA and cognitive impairment was also the conclusion drawn in one recent systematic review and meta-analysis (12). In another meta-analysis of six prospective studies that included 212,943 participants more than 40 years of age, the authors concluded that adults with OSA were 26% more likely to develop significant cognitive decline or dementia at the 3-to 15-year follow-up (8).…”

Structural brain correlates of obstructive sleep apnoea in older adults at risk for dementia

“…This brain region is also known to be particularly susceptible to hypoxic insults, such as those experienced with OSA [30]. Therefore, OSA-related hypoxaemia may contribute to degeneration in this region, a notion that would be aligned with the robust association between OSA and memory decline across older clinical OSA samples [23]. While the mechanisms by which hypoxaemia may exert deleterious effects on the brain are unknown, using MRI spectroscopy we have previously shown oxygen desaturation to be associated with oxidative stress in the brain [31] and compromised brain bioenergetics during sleep [32].…”

“…As detailed previously [19], a neuropsychologist administered a comprehensive standardised test battery. While the broader battery encompassed a variety of tests, in this study we were specifically interested in verbal memory, as it is particularly associated with OSA in later life [23]. From this test battery, the Rey Auditory Verbal Learning Test (RAVLT) [24] was used to assess verbal declarative memory performance.…”

Sleep, Health and Wellness at Work: A Scoping Review

“…A quantitative analysis of the association between OSA and neuropsychological performance showed a small negative relationship, and it is likely that some older adults may be at risk of cognitive impairments attributable to OSA; however, the connections between OSA and cognitive ability in working life vary considerably and the risk of bias renders evidence inconclusive [ 106 ]. According to the official consensus statement of the American Thoracic Society Research, there is no conclusive evidence that mild OSA leads to significant neurocognitive and cardiovascular complications [ 107 ].…”