Dementia: Phototherapy treatments show promise in improving cognitive function

Phototherapy, also known as light therapy, is a non-invasive treatment using a bright light. Depending on the condition, different types, wavelengths, and colors of light are used.

Currently, phototherapy using ultraviolet light is most commonly used as a treatment for skin diseases, including eczema, psoriasis, and vitiligo. Ultraviolet light, or UV light, is the same type of light that comes from the sun.

In addition to skin diseases, phototherapy has been used to treat seasonal affective disorder (SAD) and sleep disorders.

Scientists are also studying phototherapy as a potential treatment for rheumatoid arthritis, certain cancers, and bacterial infections.

There have been previous studies looking at the impact of phototherapy on people with dementia. A study in 2022 found phototherapy interventions were associated with cognitive improvement in patients with dementia.

And researchers at the Icahn School of Medicine at Mount Sinai are in the midst of five-year research to see if certain combinations of light therapies help slow down Alzheimer’s symptoms.

In this study, researchers analyzed the published results of 12 randomized clinical trials involving people with dementia receiving phototherapy treatments. The entire study included data from 766 people with dementia, with some receiving phototherapy and others not.

According to the scientists, the primary outcome of this study was to see how phototherapy impacted cognitive function as measured by the Mini-Mental State Examination (MMSE) score.

Upon analysis, researchers found the phototherapy treatments significantly improved MMSE scores in participants with dementia.

The second focus of the study was to see how phototherapy interventions affected the behavioral and psychological symptoms of dementia (BPSDs) — such as depression and agitation — and sleep. The researchers stated there were no significant differences in BPSDs and sleep between the phototherapy and control groups.

“In general, phototherapy appears to be a promising non-pharmacological intervention without significant adverse effects,” the researchers stated in their study. “Therefore, further well-designed studies are needed to explore the most effective clinical implementation conditions, including device type, duration, frequency, and time.”

After reviewing this study, Dr. David A. Merrill, an adult and geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center at Providence Saint John’s Health Center in Santa Monica, CA, told Medical News Today it was surprising to hear the study’s finding was primarily related to improved cognition.

“It’s definitely been demonstrated that providing light and non-invasive phototherapy stimulation can help the brain. And so it’s promising findings that need to be both replicated and expanded into clinical populations using devices that are then assessed for approval to be prescriptive interventions, assuming (there are) positive results.”

– Dr. Merrill

Dr. Merrill said he would think of phototherapy as a low risk complementary treatment added to prescription drugs and/or other more allopathic medical interventions.

“This could be something that could be done in parallel with other rehabilitation approaches for memory loss,” he explained. “The question would be how much efficacy or how much therapeutic benefit will we find with these various devices? And how do you cover the costs, because certainly, you don’t want to put a large amount of time and effort into something that (is) either unproven or doesn’t work.”

“So it’s a promising finding to show that there may be a signal there for benefits, but it needs to really be detailed out before it can become part of a routine recommendation in clinical practice,” Dr. Merrill added.

MNT also spoke with Dr. Karen D. Sullivan, a board certified neuropsychologist and creator of I CARE FOR YOUR BRAIN in Pinehurst, NC, about this research and its findings.

Dr. Sullivan noted that some of the studies reviewed for this research may not have used ideal methodologies to obtain their data and findings:

“In one of the studies in which they saw a slight improvement in MMSEs, they used a sample of convenience, meaning they just took whatever individuals with dementia were available at a dementia day program.

Dementia is a very heterogeneous group of clinical disorders and when you have a small sample size like in most of these research cases, you are likely comparing apples and oranges. Meaning, yes, they all have dementia, but the reasons they all have dementia are likely very different.”

Dr. Sullivan also said the studies may have had significant variability in the type of neurodegeneration or the time of day at which the MMSE data was collected.

“For example, people with Alzheimer’s disease have significantly worse cognition around dusk and people with Lewy body dementia have significant variability all throughout the day,” she continued. “Further, most of these studies to date have significantly different research methodologies and did not control for types, intensities, and durations of light exposure.”

All in all, Dr. Sullivan said there is the potential promise for regulating exposure to bright natural light in individuals with dementia.

“I would like to see stronger research design including clearly defined experimental groups, larger sample sizes, and standardized types, intensities, and durations of phototherapy interventions,” she added.