- Light therapy — a type of treatment where patients are exposed to artificial light for a period of time — is often used to address conditions such as depression and sleep disorders.
- Researchers reviewed studies on the effects of light therapy on patients with neurodegenerative diseases (NDs).
- Many patients in the studies saw an improvement in both their quality of sleep and symptoms exhibited during the daytime.
Studies indicate that sleep disruption can also contribute to neurodegeneration and memory impairment. For example, it is associated with an increased risk of NDs, such as Alzheimer’s and Parkinson’s diseases.
While scientists have not yet found cures for these conditions, a group of researchers believe there may be another way to alleviate some of the symptoms.
A research team based in China reviewed studies on the use of light therapy in treating these diseases, and they think it could be a game changer.
NDs affect the brain by impacting the central and peripheral nervous systems. This group of conditions includes Alzheimer’s and Parkinson’s diseases.
Alzheimer’s disease is a progressive condition that can cause memory loss, behavioral issues, and confusion, among other problems. According to the Alzheimer’s Association, it affects approximately 6 million people in the United States.
Parkinson’s disease has a slightly different effect on the body. It targets the nervous system and leads to movement-related difficulties, such as tremors, rigid muscles, and balance issues.
According to the Sleep Foundation, light therapy is “designed to treat certain health conditions through exposure to artificial light.”
People receiving light therapy sit in front of a light box daily. Depending on how strong the light is, they may spend anywhere between 20 minutes and 2 hours in front of a light box per day.
The therapy works by mimicking sunlight, which can help regulate a person’s circadian rhythms. These 24-hour cycles are part of the body’s internal clock and carry out essential functions and processes.
The sleep-wake cycle is one of the most widely recognized circadian rhythms. If it is thrown off, it can lead to undesirable physical and mental changes in the body.
While using light therapy to treat depression and other disorders is well documented, research indicates this type of treatment may have more applications.
The latest light therapy research and its clinical application were reviewed by researchers from China, whose findings were comprehensively summarized in a recent article published in the Chinese Medical Journal.
“While light therapy has been investigated in mental and sleep disorders, comprehensive knowledge on its use in [NDs is] lacking. We therefore sought to shed light on the potential therapeutic methods and implications of light therapy.”
– Dr. Chun-Feng Liu, lead author
The authors of the review acknowledge the advancements in reducing symptoms of these diseases. At the same time, they say the current treatments “can only slow down the progression of the disease but not provide a cure.”
Since sleep issues often affect people with NDs, the researchers looked into different studies on light therapy and its effects in patients with an ND. They were curious whether light therapy, which typically improves the quality of sleep, would reduce symptoms.
“Sleep disturbance is associated with increased expression of biomarkers of [Alzheimer’s disease],” the authors write. Additionally, sleep problems are reported with Parkinson’s.
Some issues that disrupted sleep can cause include increased irritability, daytime drowsiness, problems with memory, and hyperactivity.
The studies the authors reviewed were generally favorable toward light therapy helping alleviate some symptoms of Alzheimer’s and Parkinson’s diseases, such as sleep disorders, cognitive dysfunction, and depression.
However, some studies reported limited or no effects. In one study mentioned by the authors, researchers divided 70 people with Alzheimer’s disease into two groups.
The control group received their typical indoor light of 150–200 lux, where lux indicates the intensity of light. The experimental group, which received light therapy, was exposed to light at 2,500 lux Monday through Friday for 10 weeks.
The authors state that “experiments showed the circadian rhythm and cognitive function improved remarkably in the questionable and mildly demented patients group.“
However, the study in question did not show much improvement in patients with moderate or severe dementia.
The authors suggest this could be because the patients were already undergoing other treatments, and their sensitivity to light could have been impacted by the severity of the progression of their disease.
The authors believe that more research and clinical trials are needed to determine whether light therapy should become a standard treatment.
Further research is also necessary to establish what intensity of light therapy is helpful for these diseases.
If future studies continue to show promising results, light therapy could be an inexpensive and easily accessible treatment option for people with certain NDs.
“The light box or light therapy lamp will help improve the sleep quality of patients with sleep disorders,” says Dr. Liu. “Light stimulation will also likely have therapeutic effects on [NDs] and seasonal depression.”