- A new study from Austria supports the idea that light therapy may help people with multiple sclerosis (MS) reduce the overwhelming fatigue that often accompanies the disease.
- While the authors of the study sought to confirm the effect of bright light therapy, they found that even dim red light produced a similarly clinically significant improvement.
- Further research is necessary to explore the use of light therapy, a treatment with minimal side effects, for MS fatigue.
A new study from the Medical University of Vienna in Austria has investigated the value of bright light therapy for treating the debilitating fatigue that frequently occurs with multiple sclerosis (MS).
Since a 2014 study found that higher levels of sun exposure were associated with an improvement in MS fatigue, there has been an interest in light therapy as a non-pharmaceutical treatment for the condition.
The new study reports the results of a double-blind, randomized sham-controlled trial, in which participants, all of whom were people with MS, underwent treatment with bright white light therapy. A control group underwent treatment with dim red light.
The study found that bright white light therapy resulted in a clinically significant improvement in MS fatigue after just 14 days of treatment.
The new study is published in Multiple Sclerosis Journal — Experimental, Translational and Clinical.
The impact of MS fatigue
According to the National Multiple Sclerosis Society, severe fatigue affects 80% of people with MS. It typically occurs on a daily basis, and is often cited as the factor that causes people with MS to forgo working.
MS fatigue is a more profound sense of tiredness than normal fatigue.
Other people may consider its symptoms to be signs of depression or a failure to engage on the part of the person with MS, but it is a recognized symptom of the disease.
The fatigue may become worse over the course of a day, and is also aggravated by humidity and heat.
The mechanistic cause of MS fatigue is not currently known, although it is clear that it is not the direct product of depression or related to the extent of MS-related physical issues.
Promising effects vs. limitations
Researchers began with 26 participants before factoring out individuals with potential confounding causes of fatigue. They arrived at a final study cohort of 10 individuals who would be treated with bright white light and 12 people who would receive the dim red light — sham treatment — as a control group.
The authors cite this small study population as a limitation of their study.
Recruitment for the elaborate study was difficult, researchers started recruiting less than 3 months before Austria enacted COVID-19 lockdowns. It required participants to visit the researchers’ outpatient clinic, undergo rigorous sleep analyses, and respond to questions up to four times each day for 6 weeks.
General fatigue, poor mental health, and poor sleep associated with the pandemic, the authors suggest, may also have limited the effectiveness of bright light therapy.
Both groups received a treatment lamp for use in their homes. The bright light group participants were given a 10,000-lux bright white light lamp for the study.
The control group received a much dimmer lamp that produced a red light with an intensity lower than 300 lux. Both groups were expected to use their lamps for a half hour each day.
In the bright light group, the researchers observed several indicators of improvement, including improved physical and mental performance and less daytime sleepiness.
“The findings from our study represent a promising non-drug therapeutic approach,” says study author Dr. Stefan Seidel, from the Department of Neurology at the Medical University of Vienna and University Hospital Vienna.
Fatigue scores: A different story
The primary outcome researchers sought was an improvement in MS fatigue for each individual as measured using the Fatigue Severity Scale (FSS).
At the end of the trial, there was little difference between the FSS scores of the bright light or sham groups, though they both produced an improvement that qualified as clinically significant.
The authors write that, “[w]hile failing to demonstrate an effect of [bright white light] that goes beyond that of a placebo effect, our results are in agreement with the favorable impact of [bright white light] on MS-fatigue reported.”
“In essence,” Dr. Jonathan Cedernaes, circadian rhythm expert at Uppsala Universitet in Sweden, told Medical News Today, “we may need larger and more long-term studies — the present study only comprised a 2-week intervention period.”
Dr. Cedernaes was not involved in the current study.
According to him, the improvements caused by both types of light may be a case of a placebo effect. “This may be [simply] due to being part of the study,” he conjectured.
Another issue with the study is that researchers did not track participants’ time spent outside in natural light during the study period. The amount of light varies across seasons.
The promise of light therapy
Dr. Cedernaes told us that:
“Many neurodegenerative conditions disrupt circadian rhythms, and this is a great research area that requires more studies to understand cause and effect. There has […] been interest in whether circadian disruption — such as that caused by chronic shift work — can increase the risk of MS. There is some support for such an association.”
He noted, in addition, that there is “evidence to suggest that in patients who have developed MS, more severe circadian disruption at the individual level, is associated with more severe disease symptoms, such as fatigue.”
Light is especially attractive as a therapy because it has minimal side effects, allowing physicians to safely test it as an adjunct to other treatments a patient is receiving.
A recent meta-analysis, noted Dr. Cedernaes, was encouraging, suggesting that light therapy used alongside antidepressant drugs is superior to the same drugs with a placebo.
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