The researchers found that during sleep important brain waves are produced which play a vital role in storing memories. The brain waves transfer memories from a part of the brain called the hippocampus to the prefrontal cortex, a part of the brain where long term memories are stored.
Poor quality sleep in adults causes memories to stay stuck in the hippocampus and not reach the prefrontal cortex. This results in forgetfulness and difficulty remembering names.
According to UC Berkeley sleep researcher Matthew Walker, an associate professor of psychology and neuroscience:
"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."He added:
"When we are young, we have deep sleep that helps the brain store and retain new facts and information," Walker said. "But as we get older, the quality of our sleep deteriorates and prevents those memories from being saved by the brain at night."
In non rapid-eye movement sleep, the brain produces waves from the middle frontal lobe, as this part of the brain deteriorates - which commonly happens among elderly - it undermines the ability to enter deep sleep, which is crucial for storing memories.
The finding is very promising for the future and development of treatments for memory loss among the elderly. A previous German study was able to effectively enhance deep sleep in adults using electrical stimulation, the improved sleep greatly helped with overnight memory.
The researchers are planning on conducting a further study to see if there is a way of enhancing sleep among the elderly which would allow proper storage of memories and reduce overall forgetfulness.
Lead author of this study Bryce Mander, a postdoctoral fellow in psychology at UC Berkeley, said: "Can you jumpstart slow wave sleep and help people remember their lives and memories better? It's an exciting possibility."
Poor sleep among elderly causes impaired memoryThe study involved assessing the memory after sleeping of 18 young adults in their 20s and 15 older adults in their 70s.
The subjects were tested on 120 word sets before they went to bed and a electroencephalographic (EEG) machine monitored their brain activity while they were asleep. When they woke up they were tested once again on the word pairs, however this time they took the tests while undergoing functional and structural Magnetic Resonance Imaging (fMRI) scans.
The quality of deep sleep among the older adults was 75 percent lower than the younger ones, and as a result their memory was significantly worse the next day - 55 percent worse. They found evidence to suggest that deterioration of the frontal lobe is linked with impaired wave activity.
The American Academy of Sleep Medicine published a recent report highlighting the difficulties associated with sleep in the elderly and how as people age they are at a greater risk of developing sleeping problems.