In a new study, researchers suggest that Alzheimer’s disease directly attacks brain regions responsible for wakefulness during the day.
This means Alzheimer’s disease could destroy neurons that keep people awake.
It can explain why excessive daytime napping can develop long before the memory problems linked to Alzheimer’s disease.
The research was conducted by UC San Francisco scientists.
Researchers and caregivers have noted that excessive daytime napping occurs much earlier than the cognitive decline in Alzheimer’s disease.
Previous studies have considered this excessive daytime napping to be compensation for poor nighttime sleep caused by Alzheimer’s-related disruptions in sleep-promoting brain regions.
But others have argued that the sleep problems themselves contribute to the progression of the disease.
In the new study, the team precisely measured Alzheimer’s pathology, tau protein levels and neuron numbers in three brain regions involved in promoting wakefulness from 13 deceased Alzheimer’s patients and seven healthy people.
They demonstrated that brain regions controlling wakefulness are among the first casualties of neurodegeneration in Alzheimer’s disease.
Therefore, excessive daytime napping—particularly when it occurs in the absence of significant nighttime sleep problems—could serve as an early warning sign of the disease.
The team associated this damage with a protein known as tau, and the finding adds to evidence that tau contributes more directly to the brain degeneration that drives Alzheimer’s symptoms than the amyloid protein.
The researchers say the wakefulness-promoting network is particularly vulnerable in Alzheimer’s disease.
Understanding why this is the case is something the team plans to follow up in future research.
One author of the study is Lea T. Grinberg, MD, Ph.D., an associate professor of neurology and pathology at the UCSF Memory and Aging Center.
The study is published in Alzheimer’s and Dementia.
Copyright © 2019 Knowridge Science Report. All rights reserved.
