People with obstructive sleep apnea (OSA) have difficulty recalling details from their past and are at greater risk for depression, according to a study published in the Journal of the International Neuropsychological Society.1

Researchers at RMIT University in Melbourne conducted a study to determine whether individuals with untreated OSA have impaired memory compared with age-matched controls. Participants in the study included 44 adults with untreated OSA and 44 healthy adults without OSA. The investigators assessed the participants’ recollection of autobiographical memories from childhood, early adulthood, and recent times.

The untreated OSA group had more overgeneral memories – memories that cannot be recalled in great detail – than the control group (52.3% compared with 18.9%).

The investigators also looked at semantic memory and episodic memory. The former describes the recall of facts and concepts whereas the latter describes the recall of broader events or episodes. The untreated OSA group struggled with semantic memory but not episodic memory. Poor semantic memory was strongly correlated with greater depressive symptoms.

“Our study suggests sleep apnea may impair the brain’s capacity to either encode or consolidate certain types of life memories, which makes it hard for people to recall details from the past,” said Melinda Jackson, MD, a senior research fellow at RMIT and lead investigator in the study.2

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“Sleep apnea is also a significant risk factor for depression so if we can better understand the neurobiological mechanisms at work, we have a chance to improve the mental health of millions of people.”

Dr Jackson concluded that the results reveal a need for further studies about the role of untreated OSA on memory processing.

References

  1. Delhikar N, Sommers L, Rayner G, et al. Autobiographical memory from different life stages in individuals with obstructive sleep apnea. J Int Neuropsychol Soc. 2019;1-9.
  2. Sleep apnea creates gaps in life memories. Science Daily. January 31, 2019. Accessed February 11, 2019.