Rensselaer Research Team Sheds Light on a Good Night’s Sleep for Those With Alzheimer’s
Troy, N.Y. — The results of a recent pilot study has found
that Alzheimer’s patients sleep better through the night if
they are exposed to blue LED lighting a few hours before
bedtime. The study was conducted by a research team led by
Mariana Figueiro at the Lighting Research Center (LRC) at
Rensselaer Polytechnic Institute.
Light regulates the 24-hour sleep-wake cycle in healthy
humans. Typically, the body’s temperature is high during the
day, allowing people to remain alert and active. The
temperature is low at night, which facilitates sleep.
But those with Alzheimer’s disease often wake up numerous
times at night causing them to fall asleep more often during
the day. The major result is nighttime wandering, a top factor
in why patients are institutionalized.
Figueiro’s team conducted the light study for 30 days at the
Schuyler Ridge Residential and Adult Day Health Care Center in
Clifton Park. The team chose blue LEDs (light-emitting diodes)
because recent research has shown that short wavelength (blue)
light is maximally effective at affecting the circadian system
whereas middle wavelengths (yellow-green) are better for visual
performance. The circadian system is composed rhythms that
repeat at approximately every 24 hours.
Four Alzheimer’s patients were exposed to about 20 watts of
blue LED lighting two hours before bedtime, 6- 8 p.m., for two
10-day periods. Red LEDs were used to control for placebo
Figueiro’s team found that blue light exposure delayed the
decline of the patients’ body temperatures by two hours. In
other words, they slept better between two and four hours after
the light exposure. Furthermore, the two patients who wore the
wrist activity monitors showed more activity during daylight
than at night. To confirm these findings, the LRC plans to
replicate this study in a larger population.
An article about the study was accepted for publication in
Sleep Review magazine.
Contact: Jodi Ackerman
Phone: (518) 276-6531