Lighting tailored to the needs of an individual can improve sleep and reduce depression and agitation in persons with Alzheimer’s disease, according to a recent study led by Dr. Mariana Figueiro, Light & Health Program Director at the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute in Troy, New York.
The study, published in the April 2016 Lighting Research & Technology Journal is the latest in a series of high-impact papers dating back to 2010, when Figueiro started conducting research funded by her first R01 grant from the National Institute on Aging.
Older adults in long-term care facilities often spend their days and nights in dimly-lit rooms with minimal time spent outdoors. The constant, unvarying dim light found in many long-term care facilities means that older adults are not experiencing the robust daily patterns of light and dark that synchronize the body’s circadian clock to local sunrise and sunset. Disruption of this 24-hour rhythm of light and dark affects every one of our biological systems from DNA repair in single cells to melatonin production by the pineal gland in the brain. Circadian disruption is most obviously linked with disruption of the sleep-wake cycle—feeling sleepy during the day and experiencing sleep problems such as insomnia at night—but is also linked with increased risk for diabetes, obesity, cardiovascular disease and cancer.
Sleep problems are all too common among older adults, especially those in long-term care facilities, yet sleep could not be more important to their overall health and wellbeing. In fact recent research has shown that poor sleep may directly impact the onset and progression of Alzheimer’s disease, and conversely, healthy sleep may prevent or slow progression of the disease.
In the new study, LRC researchers focused on a specific challenge: delivering light in a way that was highly effective for individuals with Alzheimer’s disease. To meet this challenge, the LRC developed a self-luminous light table to complement the custom-built overhead and ambient lighting systems used in the previous phase of the study.
“The light table is a key component of the tailored lighting system because it can deliver a strong dose of light at the eyes, which is important for stimulating the circadian system,” said Figueiro.
The first light table, installed at the Albany County Nursing Home in Albany, New York, has garnered praise from caregivers and residents alike. The study was featured in the January issue of the American Psychological Association’s Monitor on Psychology magazine.
For the most recent phase of the study, now underway and enrolling new participants, the research team installed tailored lighting at several long-term care facilities throughout the U.S., including the MorningView Assisted Living Center in South Bend, Indiana. Staff members at MorningView have already seen improvements from the new lighting.
“Residents are now sleeping through the night. We have also seen a vast improvement in their mood,” said Dr. Suhayl Nasr, Psychiatry Medical Director of Beacon Health System, who introduced the lighting project to MorningView Assisted Living Center.
The tailored light treatment provides cool, high light levels for high circadian stimulation during the daytime, delivering a circadian stimulus (CS) of 0.4. A CS of 0.4 translates to approximately 2000 lux at the cornea of 25,000 K (bluish white) light, similar to a blue sky on a clear day.
Results show that the tailored light treatment significantly improved sleep, significantly reduced depression, and significantly reduced agitation in Alzheimer’s patients. Both depression and agitation scores remained significantly lower after removal of the intervention, suggesting a beneficial carryover effect of the light.
Among the many positive outcomes of this project is the fact that the lighting principles and technologies utilized in these long-term care facilities can be transferred to benefit other populations: newborns in the NICU, students in schools, office workers, and eventually, the general public in their own homes.
“Today, many people think of light as just part of a building,” said Figueiro. “In the future, light will be more personalized and customizable, with the goal of improving human health and wellbeing.”
LRC’s 24-hour lighting scheme demonstration room provides cycled electric lighting with cool, high light levels during the day and warm, low levels in the evening. Construction of the room was made possible by the Light and Health Alliance: Acuity Brands, Cree, GE Lighting, Ketra, OSRAM Sylvania, Philips Lighting, and USAI Lighting.
About the Lighting Research Center
The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute is the world's leading center for lighting research and education. Established in 1988 by the New York State Energy Research and Development Authority (NYSERDA), the LRC has been pioneering research in energy and the environment, light and health, transportation lighting and safety, and solid-state lighting for more than 25 years.
In 1990, the LRC became the first university research center to offer graduate degrees in lighting and today the LRC offers both a M.S. in lighting as well as a Ph.D. to educate future leaders in lighting. Internationally recognized as the preeminent source for objective information on all aspects of lighting technology and application, LRC researchers conduct independent, third-party testing of lighting products in the LRC's state of the art photometric laboratories, the only university lighting laboratories accredited by the National Voluntary Laboratory Accreditation Program (NVLAP Lab Code: 200480-0). LRC researchers are continuously working to develop new and better ways to measure the value of light and lighting systems, such as the effect of light on human health, and the effect of light on plant physiology.
The LRC believes that by accurately matching the lighting technology and application to the needs of the end user, it is possible to design lighting that benefits both society and the environment.
About Rensselaer Polytechnic Institute
Rensselaer Polytechnic Institute, founded in 1824, is the nation's oldest technological university. The university offers bachelor's, master's, and doctoral degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research conducted in a wide range of fields, with particular emphasis in biotechnology, nanotechnology, information technology, and the media arts and technology. The Institute is well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.
