Disconnection Between Self-Reported and Objective Cognitive Impairment in Obstructive Sleep Apnea

Abstract

Study objectives: Recent studies show that obstructive sleep apnea (OSA) is a possible contributor to abnormal cognitive decline in older adults. These new observations create the need to identify older adults with OSA who are at risk of the developing dementia if not treated. This study's goal was to verify whether self-reported cognitive complaints could become a useful tool to screen for objective cognitive deficits in late middle-aged and older adults with OSA.

Methods: Fifty-seven participants with OSA with an apnea-hypopnea index (AHI) ≥ 15 events/h (3% or arousal) and aged between 55 and 85 years were compared to 54 participants in a mild/non-OSA group on their ability to evaluate their objective cognitive functioning. They underwent overnight polysomnography followed by a comprehensive neuropsychological assessment. We recruited a similar proportion of participants with mild cognitive impairment (MCI) in both groups (OSA: 36.8%; mild/non-OSA: 35.2%). They filled out questionnaires assessing mood, sleep, and cognition. Group (OSA versus mild/non-OSA) × cognitive status (MCI versus non-MCI) analyses of variance were performed on cognitive complaint questionnaires.

Results: We found that among participants without objective cognitive deficits, participants in the OSA group reported more cognitive complaints compared to those in the mild/non-OSA group. Among participants with objective cognitive deficits, those in the OSA group reported less cognitive complaints compared to those in the mild/non-OSA group.

Conclusions: Participants with OSA and MCI were less aware of their deficits compared to those in the mild/non-OSA group, possibly reflecting a distinctive OSA-associated cognitive impairment. Our results underscore the importance of referring patients with OSA for a comprehensive neuropsychological assessment when an abnormal cognitive decline is suspected.

Keywords: aging; cognitive complaint; mild cognitive impairment; neuropsychology, sleep-disordered breathing; subjective cognitive decline; subjective cognitive impairment.

Figure 1. Scores on cognitive complaint questionnaires according to group and cognitive status.

This figure represents group (mild/non-OSA, OSA) × cognitive status (MCI, non-MCI) interactions for (A) Cognitive Failure Questionnaire, (B) Cognitive Difficulties Scale and (C) Self-Evaluation Questionnaire. For all questionnaires, among participants without MCI, the OSA group had more SCC than the mild/non-OSA group. However, the reverse pattern was observed among patients with MCI where the OSA group had less SCC than the mild/non-OSA group. Error bars represent standard error. * = P < .05. MCI = mild cognitive impairment, OSA = obstructive sleep apnea.