A team of researchers from Arizona State University has found that certain lighting conditions can help improve sleep and mood in older adults with dementia. The study, published this summer, showed that “biodynamic lighting,” which mimics the natural patterns of daylight, led to an average increase of 82 minutes in sleep time and reduced symptoms of depression among participants.
The research was led by Nina Sharp, assistant professor in The Design School at ASU and head of the DESmart Lab, which studies smart building technology and how people interact with their environments. Mohammed Alrahyani, a PhD student in The Design School, conducted the study as part of his dissertation. Other contributors included Shawn Youngstedt, professor in the Edson College of Nursing and Health Innovation; Mahya Fani, graduate student in The Design School; Ndeye Yague, ASU alum; Fang Yu, professor in the Edson College; Aaron Guest, assistant professor in the Edson College; and Jason Yeom, formerly an assistant professor in The Design School.
“Optimized lighting can be a very simple and cost-effective solution to make people happy and healthy and smarter,” Sharp said.
The project took place at Sunshine Village, a memory-care facility in Tempe. Ten residents with dementia participated over seven weeks. They experienced three weeks under biodynamic lighting and three weeks under constant moderate lighting while researchers measured their sleep quality, depression levels, and agitation.
“For older adults with dementia, it’s important to measure everything in their living environment rather than bringing them to the lab. It’s essential to our research but it makes it very difficult, very time consuming and very expensive, but this is the value that we really want to keep,” Sharp said.
Caregivers reported that after the trial ended residents tried to turn on the lights themselves because they liked how they felt under them.
Better sleep is considered crucial for people with dementia since poor sleep is linked to increased depression, anxiety, agitation and reduced cognitive function.
“One of the reasons that family members move their loved ones to a memory care facility is poor sleep quality,” Sharp said.
“So this is the real effect of our studies — how it can make people, especially older adults with dementia, happier and the quality of life a little bit better in those facilities.”
The timing as well as type of light proved important for results. Following this work Sharp and Yeom have launched Beyond Link—a startup focused on developing AI-based indoor environmental-control systems for adults with dementia.
“It’s an AI-based lighting condition based on preference, physiological signals and schedule,” Sharp said.
“And we assume that it can reduce the progress of cognitive decline. We need a long-term study to understand that, but this is the assumption based on the initial data that we collected.”
Light affects biological clocks or circadian rhythms controlling sleep patterns as well as cognition and mood. According to Sharp: “We need to receive this bright light at the right time so our body clock is in line with Earth’s light-dark cycle… If we are not in alignment we get a sleep disturbance which can cause mood disorders and reduction in cognition… If we receive bright light in the morning especially early…we also sleep better at night because our body is in line with Earth’s dark-light cycle.”
During their study at Sunshine Village they simulated natural cycles using blue-enriched high-intensity light mornings followed by neutral white afternoons then red-enriched low-intensity evenings. Older adults require more light due to changes associated with aging eyes—Sharp noted: “A 60-year-old person needs three times more light than a 20-year-old person… For an 80-year-old person it is six times more.” Yet some participants were sensitive even though they needed higher intensity; adjustments were made during testing when brightness was uncomfortable.
Sharp’s work aims not only at advancing scientific understanding but also bridging gaps between research findings and practical application within building design—a challenge she says persists due largely to outdated technology like fluorescent lights still common across workplaces: “Jason and I are trying to bridge this gap. When we write a paper and when we go to conferences we propose practical solutions so designers can apply that.”
Yeom added: “A long time ago researchers sent out a survey…and decided if 80% say ‘this is comfortable’ we’re just going use that temperature as rule…but now because machine learning…and AI…we can micromanage these environments…”
ASU has been recognized for its innovative approach by being named number one for innovation for eight consecutive years by U.S. News & World Report (https://news.asu.edu/20220911-university-news-asu-no-1-innovation-us-news-world-report-eighth-year?utm_source=twitter&utm_medium=asu&utm_campaign=ASURankings&utm_term=USNWR). This recognition highlights efforts such as those seen through projects like DESmart Lab’s research into smart building technologies aimed at improving lives.
“What I’m doing is really multidisciplinary,” Sharp said.
“It’s at the intersection of architecture engineering and medicine.”
