Frequently napping during the day may be a sign of fatigue or growing older, but a new study suggests it may also be a warning sign of Alzheimer’s disease.
The study, out of UC San Francisco, found that sleeping too much during the day—especially if there are no sleeping problems at night—could be a sign that the beginning of Alzheimer’s may be impacting the part of the brain associated with staying awake.
The study found that tau protein tangles may be responsible for impacting these brain regions associated with wakefulness and contributing to degeneration, rather than amyloid protein, which was previously assumed.
“Our work showed definitive evidence that the brain areas promoting wakefulness degenerate due to accumulation of tau—not amyloid protein—from the very earliest stages of the disease.”
– Dr. Lea Grinberg, Senior Author of the study
Tau Accumulation
The study examined the brains of 13 deceased Alzheimer’s patients, as well as the brains of seven healthy controls. The researchers analyzed the brain regions that were responsible for wakefulness, including the locus coeruleus, lateral hypothalamic area, and tuberomammillary nucleus. The same brain regions are also associated with narcolepsy, a disorder involving excessive sleepiness during the day.
The researchers found a good deal of tau protein buildup in all these wakefulness brain regions, with some losing up to 75 percent of their neurons.
“It’s remarkable because it’s not just a single brain nucleus that’s degenerating, but the whole wakefulness-promoting network. Crucially, this means that the brain has no way to compensate because all of these functionally related cell types are being destroyed at the same time.”
– Jun Oh, Grinberg Lab Research Associate
The press release of the study concluded that there needs to be a greater focus on how tau protein accumulates in brain regions in the earlier stages, rather than amyloid protein, as this may contribute to early stages of Alzheimer’s disease.
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