Excessive daytime sleepiness can be an early warning sign for Alzheimer's. Daily fatigue occurs long before the first memory problems associated with dementia occur.
Excessive daytime sleepiness can be an early warning sign for Alzheimer's. Daily fatigue occurs long before the first memory problems associated with dementia occur. This is evidenced by a study by the University of California (UCLA).
Earlier studies have examined sleep disorders associated with Alzheimer's disease. These are caused by disorders in the brain that stimulate sleep. Patients try to make up for the resulting nighttime sleep by daytime sleep.
Daytime sleepiness can be an early warning sign for Alzheimer's
Now UCLA scientists have given a new explanation for the phenomenon: they have shown that Alzheimer's disease during the day of the brain area attack is responsible for alertness. These brain regions are among the first victims of neurodegeneration.
Excessive daytime sleepiness – especially if there are no significant nighttime sleep problems – could therefore serve as an early warning sign for the disease. They are responsible for the accumulation of tau protein, which contributes significantly to the disease along with protein amyloid.
Tau level and number of neurons measured in the brain
For the current study, published in the journal Alzheimer and Dementia, Jun Oha researchers measured tau protein levels and the number of neurons in three brain regions responsible for alertness: in 13 deceased Alzheimer's patients and 7 healthy volunteers.
Compared with the healthy brain, they found that the Alzheimer's patient's brain at all three pro-cerebral centers examined – locus coeruleus, lateral hypothalamic area and tuberomammillary nucleus – had significant tau accumulation. And that those areas lost up to 75 percent of their neurons.
The entire brain network degenerates for alertness
"It's great because it degenerates not just one brain nucleus, but an entire network that promotes alertness," Oh said. "The brain has no way of making up for it because all functionally connected cell types are being destroyed at the same time."
The new findings are in line with a previous study that showed that people who died with increased levels of tau protein in the brain already had anxiety, depression and increased sleep disorders.
Tau closer to Alzheimer's than amyloid?
Researcher Conclusion: This research contributes to the growing recognition that tau is closely related to the actual symptoms of Alzheimer's disease by the more and more investigated amyloid protein that did not produce effective Alzheimer's therapy.
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