Could extra sleep improve memory for people with Alzheimer's?

Numerous studies have associated sleep with improved memory. But can sleep improve memory enough to help patients with Alzheimer's? This is what researchers from Washington University School of Medicine in St. Louis set out to investigate.

Extra sleep restored the ability of fruit flies with Alzheimer's-like symptoms to make new memories - a finding researchers say could offer "therapeutic potential" for humans.

Researchers at the Washington University School of Medicine conducted their study on three groups of fruit flies - whose brains regulate sleep in a similar way to humans.

In each group of flies, the researchers disabled a gene to cause different memory problems, but all of which interfered with their ability to make new memories.

In one group, the disabled gene triggered the development of a memory condition similar to Alzheimer's disease. 

Another group of flies had problems making brain connections that encode memories while another group had too many of these brain connections.

Next, the researchers increased the amount of sleep each group of flies got using one of three methods: stimulating brain cells involved in sleep, increasing the production of a protein associated with sleep or administration of a drug that simulates the activity of a chemical messenger involved in sleep.

The additional amount of sleep the flies received is the equivalent to an extra 3-4 hours sleep each day over a minimum 2-day period in humans, according to the researchers.

Extra sleep restored flies' ability to make new memories

The researchers - who published their findings in the journal Current Biology - found that the additional sleep restored the ability of all groups of flies to make new memories, regardless of the technique used to generate the extra sleep.

In all of these flies, the lost or disabled gene still does not work properly. "Sleep can't bring that missing gene back, but it finds ways to work around the physiological problem."

Though the exact mechanisms behind the team's findings are unknown, they hypothesize that additional sleep boosts brain cell connections that encode important memories while reducing the brain connections that encode worthless information.

While further research is needed to fully understand the association between additional sleep and memory problems, the team believes their findings pave the way for new treatment strategies for neurological conditions that affect memory, like Alzheimer's.

Their data showed that extra sleep can handle any of these [memory] problems. It has to be the right kind of sleep, and they're not sure how to induce this kind of slumber in the human brain yet, but their research suggests that if they can learn how, it could have significant therapeutic potential.

References:

1.  Sleep Restores Behavioral Plasticity to Drosophila Mutants, Stephane Dissel, et al., Current Biology, doi: 10.1016/j.cub.2015.03.027, published online 23 April 2015, abstract.
2.  Washington University St. Louis news release, accessed 23 April 2015 via Newswise.