A new study suggests that three regions of the brain involved with keeping people awake during the daytime are among the first casualties of the degenerative conditionAlamy

Excessive daytime napping can be an early warning sign of Alzheimer’s, according to new research into how the disease attacks the brain.

It was already known that Alzheimer’s can disturb the ability to sleep at night and it had been thought that patients napped during the day to catch up.

However, a study published today in the journal Alzheimer’s and Dementia suggests that three regions of the brain involved with keeping people awake during the daytime are among the first casualties of the degenerative condition.

Researchers linked the damage to a protein called tau, suggesting that it may contribute more directly to the brain degeneration that drives symptoms than a more extensively studied protein known as amyloid.

“Our work shows definitive evidence that the brain…