Sleep history predicts late-life Alzheimer's pathology

Findings suggest novel, sleep-based diagnosis and treatment methods

June 18, 2019

Science Daily/Society for Neuroscience

Sleep patterns can predict the accumulation of Alzheimer's pathology proteins later in life, according to a new study of older men and women published in JNeurosci. These findings could lead to new sleep-based early diagnosis and prevention measures in the treatment of Alzheimer's disease.

Alzheimer's disease is associated with disrupted sleep and the accumulation of tau and proteins in the brain, which can emerge long before characteristic memory impairments appear. Two types of hippocampal sleep waves, slow oscillations and sleep spindles, are synced in young individuals, but have been shown to become uncoordinated in old age.

Matthew Walker, Joseph Winer, and colleagues at the University of California, Berkeley found a decrease in slow oscillations/sleep spindle synchronization was associated with higher tau, while reduced slow-wave-activity amplitude was associated with higher ?-amyloid levels.

The researchers also found that a decrease in sleep quantity throughout aging, from the 50s through 70s, was associated with higher levels of ?-amyloid and tau later in life. This means that changes in brain activity during sleep and sleep quantity during these time frames could serve as a warning sign for Alzheimer's disease, allowing for early preventive care.

https://www.sciencedaily.com/releases/2019/06/190618102725.htm

Lighting intervention improves sleep and mood for Alzheimer's patients

Daytime light exposure decreases sleep disturbances, depression and agitation

June 5, 2018

Science Daily/American Academy of Sleep Medicine

A tailored lighting intervention in nursing homes can positively impact sleep, mood and behavior for patients with Alzheimer's disease, according to preliminary findings from a new study.

People with Alzheimer's disease and related dementias may experience sleep problems, wandering, and associated daytime irritability. This study tested whether a tailored daytime lighting intervention could improve sleep and behavior in Alzheimer's patients living in long-term care facilities.

Compared to baseline and to the inactive lighting condition, the lighting intervention significantly decreased sleep disturbances, depression and agitation. While all measures improved, the most significant improvement was seen in sleep quality.

"Here we show that if the stimulus (light dose) is carefully delivered and measured, it can have a strong impact on sleep, depression and agitation," said principal investigator and lead author Mariana Figueiro, PhD, a professor and director at the Lighting Research Center at Rensselaer Polytechnic Institute in Troy, New York. "Depression was a secondary measure, and I was pleasantly surprised by the positive impact of the light treatment on depression scores."

The study involved 43 subjects diagnosed with Alzheimer's disease and related dementias who were exposed to an active and inactive tailored lighting intervention for successive 4-week periods, spaced by a 4-week washout period. The lighting intervention was added to spaces in which patients spent most of their waking hours and was energized from wake time until 6 p.m. Calibrated personal light meters monitored exposures. Measures of sleep disturbances (Pittsburgh Sleep Quality Index), mood (Cornell Scale for Depression in Dementia) and agitation (Cohen-Mansfield Agitation Index) were collected at baseline and during the last week of the intervention.

https://www.sciencedaily.com/releases/2018/06/180605083043.htm