Deep sleep may slow Alzheimer’s progression

A study of 60 people aged 60 and older with mild or moderate Alzheimer’s disease found that deep sleep may slow the illness even when orexin levels are high.

An international research team monitored participants’ brain waves and sleep cycles overnight, then analyzed cerebrospinal-fluid samples collected the following morning. Researchers measured orexin, a chemical messenger involved in regulating the sleep-wake cycle, and tracked participants’ cognitive condition for three years.

Patients with higher cerebrospinal-fluid orexin levels showed faster worsening of Alzheimer’s symptoms during that period. But among those who experienced stronger slow-wave brain activity during deep NREM sleep, the disease progressed much more slowly despite elevated orexin levels.

The researchers also found that female participants had notably higher orexin levels than male participants. Experts said approaches that improve deep-sleep quality and regulate orexin could help the brain clear amyloid and tau, toxic proteins linked to memory loss. They said such treatments could open a new path toward slowing Alzheimer’s progression.