Associations Between the Apnea-Hypopnea Index During REM and NREM Sleep and Cognitive Functioning in a Cohort of Middle-Aged Adults

Current Knowledge/Study Rationale: Although there is evidence that a higher apnea-hypopnea index (AHI) may be associated with cognitive impairment, it is not known whether the association varies by the AHI measured during rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. We also investigated whether this association varies according to the presence of the apolipoprotein E4 allele (APOE4). Study Impact: We found that among APOE4 carriers, higher REM AHI is associated with worse psychomotor speed and higher NREM AHI is associated with worse memory retention. Our study provides the first investigation of the associations between AHI during different sleep states and cognition. Furthermore, our results suggest the possibility that exposure to AHI levels during various sleep states may affect different cognitive domains.