Scientists have discovered an unexpected reason why Alzheimer's disease disrupts sleep, and their findings suggest that the problem may be reversible. In experiments involving mice with Alzheimer's-like brain changes, researchers restored more than two hours of sleep per day without removing the amyloid plaques associated with the disease.

The surprising discovery points to an overlooked culprit: the brain's own immune cells. Rather than simply protecting the brain from damage, these cells can trigger inflammation that interferes with healthy sleep.

Researchers at the University of Kentucky found that temporarily eliminating most of these immune cells allowed the mice to sleep longer and spend more time in the deep, restorative stages of sleep. The results suggest a potential new approach to treating one of the most disruptive symptoms of Alzheimer's disease.