In its most general sense light therapy refers to the use of light, typically red or near-infrared light, to stimulate and heal injured tissue. One of the major mechanisms by which light therapy is thought to work is by improving the mitochondrial function of compromised cells. The improved mitochondrial function leads to an increase in ATP production, providing the energy needed for the cells to heal . Research supporting the use of light therapy for a number of disorders, including those of the brain, has been overwhelmingly good.
Related: 5 Ways Light Therapy Heals the Brain
Sources of Light Therapy
Sunlight was used long before the invention of antibiotics to speed healing of wounds, treat skin diseases, and even fight infections. Physicians in ancient Greece would often prescribe sunbathing to promote good health and vitality. Today, we have shifted our focus from the benefits of sun exposure to the hazards. How could this outlook be affecting our brains?
Sunlight is the main source of vitamin D for most people. Due to a lack of adequate exposure to the sun, vitamin D deficiency is now recognized as a worldwide pandemic . Over 1,000 different genes in the body are regulated by vitamin D . A study investigating vitamin D and brain development found that it stimulates the production of neurotransmitters and improves synaptic density .
Other studies have linked lower levels of sunlight to cognitive impairment .
Finally, sunlight influences our circadian rhythm by impacting melatonin and serotonin levels in the blood. Exposure to sunlight in the morning boosts melatonin production at night translating to faster sleep onset. High serotonin levels from adequate sun exposure result in a more positive mood and a calm, focused metal state .
Light Emitting Diode (LED)
LED therapy is noninvasive, painless, and non-thermal. It has been cleared by the United States FDA as an insignificant risk device . Compared to lasers, LEDs are inexpensive, easy to obtain for at home use, and vary widely in size making it easier to treat larger areas of the body. Though there isn’t a lot of research available for LEDs as a treatment for the brain, the existing research has been encouraging.
In one case study two subjects with traumatic brain injury applied an LED array to their foreheads. After eight weeks of LED treatments, subject 1’s ability to concentrate on a task increased from 20 minutes to 3 hours. She also reported better memory when reading, improved math skills, and decreased sensitivity of her scalp. When the study began, subject 1 was seven years post injury. Subject 2 had been on medical disability for 5 months prior to treatment, but after 4 months of LED treatments she was able to return to work. Additionally, neuropsychological testing showed a significant improvement in her memory and executive functioning .
A similar study was performed on eleven subjects to determine if LED therapy could improve cognition in patients with mild traumatic brain injury. The subjects ranged from 10 months to 8 years post-TBI. The subjects’ cognitive performance levels were tested periodically and a significant positive trend was observed for cognitive performance and LED treatment over time. Additionally subjects reported improved sleep, fewer PTSD symptoms, and enhanced ability to perform social functions .
Cold laser therapy is also known as low-level laser therapy (LLLT) or photobiomodulation. Lasers differ from LEDs in that lasers are a coherent source of light. Coherent light means that all the light waves travel perfectly together in a single beam. LED light, like sunlight, is incoherent meaning each light wave can travel in a different direction than the other light waves. As a result, lasers are much more concentrated and powerful than LEDs. Here’s what the research says:
A case study involving a subject who suffered a brainstem stroke two years before beginning LLLT showed dramatic improvements after eight weeks of light therapy. Her mood and memory improved. Her double vision was eliminated. Her muscle spasticity decreased, she gained increased function in her left and right hands, and her arm and leg strength increased .
A patient with a moderate TBI showed favorable results after receiving laser treatments for two months. After receiving the treatments he showed decreased depression, insomnia, anxiety, and headaches, while cognition and quality of life improved .
Additionally LLLT has shown promising results as a treatment for chronic pain .
What are the Risks?
Light therapy is generally safe, but there have been some minor side effects reported. The most common side effects include eyestrain, headaches, and nausea. Side effects are usually relieved by decreasing the amount of time exposed to the light.
Because coherent light is so powerful, there is potential that it could damage your retina if you look directly into the laser beam. To protect your eyes, you should always wear protective goggles when working with a cold laser. Eye damage is not a concern when working with LEDs, since they are a non-coherent light source.
I would recommend consulting your chiropractor or physician before starting a light therapy routine. They will be able to help you determine the best locations and length of exposure for optimum results.
Purchasing a Light Therapy Device
LED arrays are easy to obtain and fairly cheap. I would recommend buying an array that has both red (600-700nm) and near infrared light (760-940nm) to get a wider range of benefits. The one my family uses is the DPL FlexPad*. There are many to choose from so you may want to do some research and choose the one that works best for you.
Getting a cold laser is a little more complicated and the restrictions on who can own one vary from state to state. Because they are so expensive (expect to pay $5,000+) I would suggest not buying one and getting treatments from your chiropractor instead. In my experience cold laser treatments are more reasonably priced, ranging from $30 -$60 per session.
Where can I find more Information?
I would highly recommend reading Norman Doidge’s book The Brain’s Way of Healing*, even if you aren’t interested in light therapy. For light therapy, I would suggest you start with chapter seven (the chapters can be read independently so you can go back and read the earlier ones later).
Michael Hamblin is another great resource. You can search him on YouTube and find several interviews where he discusses light therapy. In addition, here is a fairly comprehensive literature review he wrote addressing light therapy and the brain.
See my other post on this topic: 5 Ways Light Therapy Heals the Brain.