On a brisk winter morning last year, Ron Till, 67, sat down at his small kitchen table in Adelaide, Australia, to read the latest edition of his quarterly newsletter from an organization called Parkinson's South Australia.
Till had been diagnosed with Parkinson's disease in his late 50s, and his symptoms were getting worse. He had difficulty concentrating, had lost his peripheral vision and could only manage a limited amount of activity each day before exhaustion overwhelmed him.
Since he had retired two years earlier, Till had spent much of his time sitting inside his brick apartment, staring out the window, feeling lonely and bored.
"Parkinson's makes you lose your confidence," Till says. "You think, 'Everybody's looking at my hands shaking.' You become more introverted."
On top of his medical woes, Till and his wife had recently separated. "It became intolerable for her," Till explained. "When I retired, my wife thought I'd be doing lots of things like volunteering and visiting friends, but I never did any of that. Parkinson's made me so tired. I could do one thing, and then the rest of the day I was useless."
Fortunately for Till, as he sipped his coffee and read the Parkinson's South Australia newsletter that morning, he came across an advertisement that would change his life.
Shedding light on the "shaking palsy"
Parkinson's disease—first described by English surgeon James Parkinson in his 1817 paper "An Essay on the Shaking Palsy"1—is a movement disorder involving tremor, muscle rigidity, impaired balance and slowness of movement. It can also cause neurological problems such as depression, poor sleep, memory loss and confusion.
Parkinson's is estimated to affect over 6 million people worldwide and is responsible for over 200,000 deaths annually.2 While its cause is unknown, it is associated with dopamine depletion and loss of neurons in the basal ganglia region of the brain.
The current mainstay of treatment is physical therapy and medications that act to increase dopamine levels in the brain. These medications can provide improvements in symptoms, but their effectiveness tends to wear off over time, and they also have side-effects.
In addition, the drugs treat the symptoms only, without actually reversing or even slowing the natural course of the disease. A neurosurgical technique called deep brain stimulation is sometimes used in cases that don't respond to drug therapy, but it, too, treats only the symptoms and carries the additional risk of surgery.
One avenue of research that has shown unexpected promise in the quest for more effective treatment is infrared light therapy. Over the past decade, a number of studies have suggested that it may protect against neurological damage and improve motor function in Parkinson's disease.3
Based on these findings, Dr Ann Liebert, coordinator of photomolecular research at the Australasian Research Institute in Sydney, and fellow researchers were planning a clinical trial of infrared light therapy for Parkinson's disease patients. They placed an advertisement seeking volunteers in the Parkinson's South Australia newsletter—the same one that caught Till's eye.
"Since my diagnosis, I'd been looking for a trial," Till said. "But it's very rare to get a trial in Parkinson's. So, when this one came up, it was like winning the lottery."
The planned trial was going to examine more than just neurological changes in Parkinson's disease. "We know that infrared light can reduce Parkinson's symptoms and offer protection to brain cells," Liebert said. "We wanted to test if it could modulate the gut's microbiome as well."
One of the principal researchers in Liebert's planned study, Dr Daniel Johnstone, a lecturer at the University of Sydney's Bosch Institute, had previously found that exposure to infrared light altered the gut microbiome in mice.4
In 2015, he had also been involved in a study of macaque monkeys with drug-induced symptoms similar to Parkinson's, which found that shining infrared light on the abdomen, as opposed to the limbs, had the strongest protective effect.
"One possibility might be that we're somehow influencing the microbes in the gut, and that's having an effect on the brain," Johnstone said.
Based on their findings in mice, Liebert and colleagues conducted a case study to see if infrared light therapy could modulate the human microbiome, in which a single subject received infrared light therapy to their abdomen three times a week for 12 weeks. Fecal samples showed a post-therapy increase of bacterial species that are considered beneficial to the gastrointestinal tract, including Akkermansia muciniphila, Bifidobacterium and Faecalibacterium.
The gut-brain connection
Liebert's new trial includes two dozen volunteers from Sydney and Adelaide. Participants are receiving 20 minutes of 810 nm infrared light therapy to their head and 20 minutes of 904 nm infrared light therapy to their neck and abdomen three times a week for four weeks, then once a week for a further eight weeks, and have their gut microbiome analyzed before and after treatment.
The trial is still ongoing, but preliminary results have been very promising.
"The six patients that have been put through a similar protocol as the mice showed an increase by up to 20 percent in the favorable microbiome, which is associated with obesity reduction and short chain fatty acid production, and the bacteria associated with rheumatoid arthritis, Crohn's disease and insulin resistance were all decreased," said Professor Hosen Kiat, medical director of the Cardiac Health Institute and Professor of Cardiology at Macquarie University.
Till, who was one of those early participants of the trial, experienced a remarkable improvement in his Parkinson's symptoms.
"The trial gave me the ability to sleep again," he said. "Ever since the Parkinson's began, I've been waking up every hour. But within the first week of using the lasers, I was able to sleep for two four-hour blocks every night, which was amazing."
Till's neurologist cautioned him not to get his hopes up before the trial but changed his mind when he saw the results. "He told me it was voodoo medicine and probably wouldn't work," Till said. "But after the trial I went back for my quarterly check-up, and he did all the standard tests and said to me, 'You're actually testing better than when you first started with me 10 years ago.'"
Other trial participants have similar success stories. Margaret Jarrett and Barry Weldon* both regained their sense of smell (something commonly impaired in Parkinson's). "One day I walked into the house, and for the first time in a long time I could actually smell the soup my wife was cooking," Weldon, 70, said.
Retired geologist Sean Kennedy, 76, experienced improvement in his coordination and balance. "My juggling skills have improved," he said. "I'm still playing tennis, too. If I hadn't had the treatment, I probably wouldn't be able to play anymore."
Of course, correlation does not equal causation, and the improvement in Parkinson's symptoms following infrared light therapy may be unrelated to the changes in the trial participants' gut microbiome.
For skeptics, it's possible that the improvements were at least partially due to the placebo effect, the well-known phenomenon whereby patients experience an improvement that cannot be attributed to the physical or biochemical properties of the treatment itself. This is especially relevant in Parkinson's, where some placebo treatments have even been shown to increase the release of dopamine in the brain.5
Despite this, the researchers believe that infrared light therapy holds great potential. In a recent review of the existing literature on light therapy or "photobiomodulation" (PBM), they conclude: "The ability of PBM to influence the microbiome (if proven to be applicable to humans) will allow an additional therapeutic route to target multiple diseases, including cardiovascular disease and Parkinson's disease, many of which have thus far eluded effective treatment approaches." 6
Kiat explains further, "If we can create, noninvasively, a metabolically healthier microbiome through this extremely cheap and easy way, then inflammatory diseases and neurodegenerative diseases should be positively influenced," he said.
These gut microbiome findings are just the latest in a long line of positive biological changes that have been observed following light therapy.
How light affects the gut
The gut's microbiome —composed of the trillions of bacteria, fungi and protozoa from hundreds of different species that inhabit our gastrointestinal tract (and containing at least as many cells as there are in our entire body)—has received increasing scientific attention over the past decade.
Changes in the microbiome have been linked to a number of medical conditions including obesity, type 2 diabetes, cardiovascular disease and depression.
Several studies have also documented that the gut microbiome is markedly altered in patients with Parkinson's disease,1 and that fecal microbiota transplantation can have a protective effect in animal models of Parkinson's.2
The reason for this is unknown; however, a common pathology seen in Parkinson's disease is the accumulation of misfolded alpha-synuclein proteins, called Lewy bodies, in the brain.
Some sensory cells of the gut also contain alpha-synuclein,3 and researchers have discovered that abnormal forms of alpha-synuclein protein can travel from the gut to the brain through the vagus nerve in animal models of Parkinson's.4
Further supporting this theory, people who have had a specific type of surgical vagotomy—where branches of the vagus nerve are cut—have a lower risk of developing Parkinson's.5
In a 2019 review article, Liebert and her coauthors write that the mechanism by which light therapy alters the microbiome could involve a direct effect of light on the microbes, on the host cells surrounding the microbes, or on the host's inflammatory, immune or stem cell systems.6
An old new therapy
In the late nineteenth century, Faroese physician Niels Finsen pioneered the use of light therapy for a range of conditions, including skin scarring following smallpox and tuberculosis infections.
In 1903, he was awarded the Nobel Prize in Medicine and Physiology for "his contribution to the treatment of diseases, especially lupus vulgaris, with concentrated light radiation, whereby he has opened a new avenue for medical science."
In 1910, Dr John Harvey Kellogg, of cornflakes fame, published Light Therapeutics, in which he advocated light therapy for conditions including diabetes, obesity, insomnia and baldness.
However, it wasn't until the 1960s, when red light-emitting lasers were found to improve hair growth in mice, that modern research into red and infrared light therapy began.
Why does infrared light heal?
Red light (625-740 nm wavelength) and infrared light (>750 nm wavelength), can penetrate human skin to a significantly deeper depth than other light wavelengths.1
One popular theory for the mechanism of action of red and infrared light therapy is that cell absorption of the light stimulates mitochondria to become more active and increase production of ATP (energy) via the enzyme cytochrome c oxidase.2
"The exact mechanisms [of light therapy] are still not totally known, but we do know that there's a key enzyme in the cells that absorbs light at certain wavelengths and triggers this intracellular cascade signaling that seems to collectively lead to a protective effect," Dr Daniel Johnstone of the University of Sydney explains.
"Light is actually a low-level stress to the cells, and when you deliver this stress, it either stimulates repair processes or it conditions the cells to upregulate stress-response systems, which in turn conditions that tissue against a more severe insult down the line—almost like a vaccination where you're giving a low-level pathogen as a way to stimulate your body's own defenses against a more severe exposure."
Professor Jonathan Stone, Executive Director at the Bosch Institute, first became interested in infrared light therapy after being presented with data from NASA showing that infrared light therapy could help grow plants in space as well as speed the healing of wounds. For more than a decade now, Stone has been researching light therapy in his own laboratory and has observed growing interest in research centers across the world.
"There's growing evidence it works against depression and stroke and in the cognitive aspects of Alzheimer's disease," he says. "And it's so blessedly free of side-effects that you can use it without having to know down to the last molecular detail how it works."
Stone explains that red and infrared light therapy likely have both direct and indirect mechanisms of action. "We have published evidence that red-light interventions have off-target effects. When investigators working with animals made a small wound on one flank of an animal and another wound on the other flank, and irradiated one with red light, the red light accelerated wound healing on both sides."
"Likewise, when other investigators made two identical abrasions on the forearms of healthy human subjects and irradiated one arm, the red light accelerated the healing of both abrasions." Furthermore, Stone adds, "The range of conditions for which red-infrared light has proved beneficial is enormous."
Finnish dental student Vladimir Heiskanen agrees, having collated an extensive list of trials on the therapeutic effects of red and near-infrared light on his website, www.valtsus.blogspot.com. His database lists over 3,800 scientific articles including, by his estimation, over 1,100 animal studies and 140 randomized controlled trials in humans.
The site documents over 50 conditions for which studies of red and near-infrared light therapy have been conducted on humans.
It has shown benefit for the treatment of hair loss, chronic low back pain, knee joint osteoarthritis, oral mucositis, post-exercise recovery and neck pain, as well as more limited evidence supporting its use for the treatment of diabetic foot ulcers, dental pain, exercise performance, breast cancer lymphedema and acute pain.
Liebert believes this list will only expand as further research into red and infrared light therapy continues, particularly, she says, "with the increasing evidence of its effectiveness in managing everything from chronic pain to post-surgical complications, postoperative cognitive dysfunction, chronic arthritis and cancer treatment complications.
Liebert, who is also vice president of the Australian Medical Laser Association, noticed that some of her patients who had red light therapy before major surgery seemed to recover more rapidly and experience less delirium and postoperative cognitive dysfunction compared to those who did not.
This has led her, in collaboration with geriatrician Dr Gregory Bennett, to apply for ethics approval for a clinical trial investigating red light therapy for Alzheimer's disease.
Bennett, who consults at the Sydney Adventist Hospital, has also noticed positive results in some of his Alzheimer's patients following red light therapy."There seems to be general improvement in their engagement in life. They seem happier and more energetic and show more initiative in doing little chores around the house."
He cautions, however, that randomized controlled trials are needed. "The difficulty is we can't really be sure that their improvements are not the effects of just the social stimulation of getting out and coming into the clinic."
Retiree Allan Wilson*, 78, believes that infrared light therapy has been beneficial for his partner Miriam Taylor's* Alzheimer's disease. Following her diagnosis three years ago, he purchased a mobile infrared light device from Vielight that delivers 810 nm wavelength light to the head via a helmet-like device. Taylor has been using the Neuro Gamma device for 20 minutes a day, six days a week, for over two years now, and Wilson is impressed with the results.
"The light is stalling her decline and giving her confidence," he said. "Both her short-term memory and confusion have improved." Taylor agrees. "I have more moments where it feels like everything has come good again and I remember things," she said.
Taylor's doctor, Gold Coast-based Dr Mark Jeffery, has been using red and infrared light therapy in his practice for over four years. He believes that the available research supports the use of light therapy for a wide range of diseases. "The next area of research I imagine will be using photobiomodulation with nano particles, and how to photoactivate those in key areas of the body so that they can release their therapy at the right place," he said.
Despite the promising findings, Stone cautions that red light therapy should be used as an add-on therapy, not an alternative to mainstream medicine. Johnstone agrees. "I wouldn't recommend that anyone with existing cancer use photobiomodulation until we understand more about how exactly it works."
Liebert says a large, double-blind, randomized control trial on photobiomodulation is planned for 2020 to look for further evidence of red light's effect on Parkinson's and more, particularly considering the promising evidence of its effect on the gut. "It has the potential to apply to huge fields of medicine," she said.
As for Till, he has no doubt that infrared light therapy has helped him. He has moved to the historic town of Mannum and is busy renovating his son's home there.
"I wouldn't have had the energy to do anything like this before, it would have been impossible," Till said.
Perhaps even more satisfying for Till has been his ability to return to his love of music. A singer and guitarist in local bands for most of his life, Till has recently finished recording an album of original songs with his brother Colin.
"We've written songs all our lives, but this is the first CD we've put together," Till said. "After the trial I thought, I can do this. I can finish this. Because you've got to leave something. Some sort of legacy."
*Names have been changed at interviewees' request
Finding a light therapy clinic
Many chiropractors, physiotherapists, podiatrists and dentists as well as trained laser therapists across the US and UK offer low-level (cold laser) light therapy as a healing modality for conditions such as pain relief, tissue repair, postoperative healing, gastrointestinal disorders and depression.
Examples include, in the United States:
Westwood Clinic in Los Angeles, CA: www.westwoodclinic.com
Liebell Clinic in Virginia Beach, VA: www.liebellclinic.com
Laser Pain Centers of Illinois in Sherman, IL: www.shermanlasercenters.com
In the United Kingdom:
Perfect Balance Clinic, London: www.perfectbalanceclinic.com
Laser Medicine, London: www.lasermedicine.co.uk
Clare Barker Therapy, Leeds: www.cold-laser-therapy.co.uk
To find a reputable clinic, contact the American Society for Laser Medicine and Surgery (www.aslms.org) or the British Medical Laser Association (www.bmla.co.uk) for more information.
Using infrared light therapy for Parkinson's and Alzheimer's
For neurological conditions such as Parkinson's and Alzheimer's disease, red or infrared light therapy applied to the head for 20 minutes per day appears to be optimal, say researchers.
Two companies involved in supplying infrared light therapy devices for the Australian Parkinson's trials are Canadian company Vielight (www.vielight.com) and Swedish company Irradia (www.irradia.com) The cost for these devices ranges from $299 to $2,639. Readers can contact these companies directly about purchasing an appropriate device for their condition.
The Dorset Men's Shed in Australia has made over 650 red and infrared light therapy helmets for members of the public, and shipped their helmets all over the world. Helmets cost $300 AUD (about $205 US and £157) plus postage. For enquiries and orders, contact Merv Chilcott at firstname.lastname@example.org.