Study: Age-Related Changes in the Brain Hurt Seniors’ Sleep, Memory Suffers

Scientists have long known that memory deterioration is a natural part of aging, but new a study has found an explanation as to why forgetfulness is common in seniors – and opens the door to treatments that can improve older adults’ memory.

A team of researchers at the University of California, Berkeley, published a study that sheds light on the cause of memory loss in seniors. The study involved an experiment that tested the memory skills of two groups of participants: one group in their early twenties, and another group of older adults.

Each participant was given a pair of words; one common word and the other a nonsensical word, such as “false-dipotabia.” They did this to ensure the participants were creating new memories, rather than recalling previously-remembered facts. After training on the pairs for half an hour, the participants were quizzed to test their remembrance of the words. The older adults scored 25 percent lower than the younger group.

The participants were then asked to sleep for the night, while the researchers monitored their brain waves. The brain waves of the senior group indicated they experienced only one-fourth of the high-quality, slow-wave sleep that the younger group did.  Previous research has shown that this type of sleep is essential in converting memories from temporary to long-term storage.

When the participants awoke, each was given a test on the word pairings. These results showed that the younger group outscored the older group by an even larger margin – 55 percent. Brain scans conducted before the testing revealed that the medial prefrontal cortex, an area of the brain that helps sustain quality sleep, was roughly one-third smaller on average in the older group than in the younger one, due to natural aging of the brain. “The analysis showed that the differences were due not to changes in capacity for memories, but to differences in sleep quality,” said Bryce A. Mander, lead researcher of the study.

“When we are young, we have deep sleep that helps the brain store and retain new facts and information,” said Matthew Walker, senior author of the study. “But as we get older, the quality of our sleep deteriorates and prevents those memories from being saved by the brain at night.”

The researchers hope their findings will lead to treatments that can improve the memory of seniors. “What we have discovered is a dysfunctional pathway that helps explain the relationship between brain deterioration, sleep disruption and memory loss as we get older – and with that, a potentially new treatment avenue,” Walker said.