Memory and Obstructive Sleep Apnea: A Meta-Analysis

STUDY OBJECTIVES: To examine episodic memory performance in individuals with obstructive sleep apnea (OSA). DESIGN: Meta-analysis was used to synthesize results from individual studies examining the impact of OSA on episodic memory performance. The performance of individuals with OSA was compared to healthy controls or normative data. PARTICIPANTS: Forty-two studies were included, comprising 2,294 adults with untreated OSA and 1,364 healthy controls. Studies that recorded information about participants at baseline prior to treatment interventions were included in the analysis. MEASUREMENTS: PARTICIPANTS WERE ASSESSED WITH TASKS THAT INCLUDED A MEASURE OF EPISODIC MEMORY: immediate recall, delayed recall, learning, and/or recognition memory. RESULTS: The results of the meta-analyses provide evidence that individuals with OSA are significantly impaired when compared to healthy controls on verbal episodic memory (immediate recall, delayed recall, learning, and recognition) and visuo-spatial episodic memory (immediate and delayed recall), but not visual immediate recall or visuo-spatial learning. When patients were compared to norms, negative effects of OSA were found only in verbal immediate and delayed recall. CONCLUSIONS: This meta-analysis contributes to understanding of the nature of episodic memory deficits in individuals with OSA. Impairments to episodic memory are likely to affect the daily functioning of individuals with OSA.