Cognitive Effects of Treating Obstructive Sleep Apnea in Alzheimer's Disease: A Randomized Controlled Study

Abstract

OBJECTIVE: To examine whether treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) in patients with Alzheimer's disease (AD) would result in improved cognitive function. DESIGN: Randomized double-blind placebo-controlled trial. Participants were randomized to either therapeutic CPAP for six weeks or placebo CPAP for three weeks followed by therapeutic CPAP for three weeks. SETTING: General clinical research center PARTICIPANTS: 52 men and women with mild-moderate AD and OSA INTERVENTION: Continuous positive airway pressure MEASUREMENTS: A complete neuropsychological test battery was administered before treatment, at three and at six-weeks. RESULTS: A comparison of subjects randomized to 3 weeks of therapeutic versus placebo CPAP suggested no significant improvements in cognition. A comparison of pre- versus post-treatment neuropsychological test scores after 3 weeks of therapeutic CPAP in both groups showed a significant improvement in cognition. The study was underpowered to make definitive statements about improvements within specific cognitive constructs. However, exploratory post-hoc examination of change scores for individual tests suggested improvements in episodic verbal learning and memory and some aspects of executive functioning such as cognitive flexibility, and mental processing speed. CONCLUSIONS: OSA may aggravate cognitive dysfunction in dementia and thus may be a reversible cause of cognitive loss in AD patients. OSA treatment seems to improve some of the cognitive functioning. Clinicians who care for AD patients should consider implementing CPAP treatment when OSA is present.

A systemic view of Alzheimer disease — insights from amyloid-β metabolism beyond the brain

“…For example, administration of statins (which reduce peripheral blood cholesterol levels) to healthy middle-aged individuals was associated with a reduced dementia risk in one large-scale prospective cohort study 149 ; statins have also decreased the brain burden of Aβ in experimental models of AD 150 , although the results of most studies of statin treatment in patients with AD have been disappointing 151 . Furthermore, treatment with continuous positive airway pressure for sleep-disordered breathing or OSA might delay the onset of mild cognitive impairment and slow or even improve cognitive decline in patients with AD 120,152,153 . These observations support the view that systemic management of an individual's known comorbidities or risk factors, with the aim of maintaining bodily homeostasis, might help to prevent or slow the progression of AD.…”

Aging and Alzheimer’s disease: Comparison and associations from molecular to system level

“…Furthermore, individuals with sleep apnea had a younger age of MCI or AD onset (Osorio et al, 2015). By contrast, successfully treating sleep disturbance can delay the age of MCI onset (Osorio et al, 2015) and improve cognitive function in AD (Ancoli‐Israel et al, 2008; dos Santos Moraes et al, 2006). Together, these findings indicate that high‐quality sleep can mitigate Alzheimer's disease pathology.…”

Sleep Pathology in Creutzfeldt-Jakob Disease

“…13 Furthermore, randomized controlled trials have demonstrated that treatment of OSA in AD patients can improve sleep quality as well as cognitive performance. [27][28][29] Although the majority of our patients died soon after their studies were performed, a few subjects (and their caretakers) benefitted from treatment of their SRBD and RBD (example case).…”