Study ties poor sleep to reduced memory performance in older adults

A new study has found that variability in night-to-night sleep time and reduced sleep quality adversely affect the ability of older adults to recall information about past events.


The study, which included 50 Atlanta-area adults, underscores the importance of sleep in maintaining good cognitive functioning.


“The night-to-night variability in the older study participants had a major impact on their performance in tests aimed at evaluating episodic memory,” said Audrey Duarte, an associate professor in Georgia Tech’s School of Psychology and principal investigator in the Memory and Aging Lab. “The association between sleep and memory has been known, but this study’s novelty is showing that the connection is particularly evident for older adults and black participants, regardless of age.”


Duarte and Emily Hokett, a Ph.D. student in the School of Psychology, recruited 81 volunteers from the Atlanta area. The volunteers were evaluated carefully to screen out those who had mild cognitive impairment or other potentially confounding factors. Younger adults were recruited in the age range of 18 to 37 years, while older adults were recruited in the range from 56 to 76 years. Ultimately, 50 adults were selected for the study.


The participants were given accelerometers worn on their wrists to measure sleep duration and quality over a period of seven nights. Though they did not measure brain waves, the devices allowed sleep measurements to be done in the participants’ own homes. The researchers sought to provide a more realistic measurement than testing done in sleep labs, which typically lasts just one night.


Participants were asked to visit a Georgia Tech laboratory for a memory test that measured electroencephalography (EEG) brain wave activity as they attempted to recall word pairs that had been shown to them earlier. Not surprisingly, better performance correlated with better sleep in most of the older adults.


“Some of our 70-year-old subjects looked like our 20-year-old students,” Duarte said. “There are many factors that contribute to individual differences.”


In future research, Duarte and Hokett hope to expand their study to a larger group of participants, to study the relationship between sleep and memory in other underrepresented minorities, and to explore whether variations in sleep patterns could predict a person’s likelihood of experiencing diseases such as Alzheimer’s.


The study’s takeaway message may be that regular sleep is important at any age for the best cognitive performance.


Improvements in sleep may be one area where people concerned about cognitive impairment may have an opportunity to make improvements.


“In understanding normative ageing, lifestyle factors are a good area to target because they are potentially factors we can control,” said Duarte. “It’s been known for decades that important things are happening while you sleep with regard to memory consolidation and strengthening of memories. Because we knew that sleep quality typically declines in normal ageing, this was a prime target for study.”


Citation: “Age and Race-Related Differences in Sleep Discontinuity Linked to Associative Memory Performance and Its Neural Underpinnings,” Frontiers in Human Neuroscience (June 2019)


5 August 2019.