Alzheimer's May Kill Cells Needed To Stay Awake

A study in Alzheimer's & Dementia suggests that Alzheimer's disease may destroy cells needed to stay awake, which may explain why those living with the disease sleep so much during the day, reports WorldHealth.net . The researchers discovered a direct link between excessive daytime napping and Alzheimer's disease, and that tau protein tangles play a larger role in the disease than amyloid plaques. Postmortem analysis of 13 brains of people with Alzheimer's compared to six healthy brains found the lateral hypothalamic area, the tuberomammillary area, and the locus coeruleus in the former cohort had significant tau accumulation that killed off up to 75 percent of the neurons in those regions. "It's remarkable because it's not just a single brain nucleus that's degenerating, but the whole wakefulness-promoting network," said the University of California's Jun Oh. Meanwhile, analysis of brain samples from seven individuals with different forms of tau-related dementia indicated that tau buildup did not affect the neural networks associated with wakefulness. The implications are that wakefulness-promoting neurons may be especially prone to the harmful effects of tau aggregation only in Alzheimer's disease, suggesting that excessive daytime napping may be an early symptom, especially if unaccompanied by or caused by significant nighttime sleep problems.