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LED Therapy Studies


Figure 1. Red/near-infrared LED cluster heads in place on the scalp, to improve cognition in persons who have had traumatic brain injury. Photo published in Naeser, Zafonte et al., 2014, Journal of Neurotrauma. (LED cluster heads from MedX Health, Toronto.)

Traumatic Brain Injury (TBI)

Margaret Naeser, PhD, VA Boston Healthcare System, Boston University School of Medicine

Scalp application of red/near-infrared LED was observed to significantly improve executive function and verbal memory in persons with chronic TBI (Naeser, Zafonte et al., 2014). This included significant improvement in inhibition (p=.004) and inhibition/switching (p=.003) on the Stroop color/word interference test, and significant improvement in ability to remember a list of words 20 minutes later (p=.006). Participants reported improved sleep, and fewer PTSD symptoms, if present. These LED treatments can also be performed in the home (Naeser, Saltmarche et al., 2011).  See Figure 1.

Naeser MA, Zafonte R, Krengel MH, Martin PI, Frazier JA, Hamblin MR, Knight JA, Meehan WP, Baker EH.  Significant Improvements in Cognitive Performance Post-Transcranial, Red/Near-infrared Light-Emitting Diode Treatments in Chronic, Mild Traumatic Brain Injury:  Open-Protocol Study. J of Neurotrauma 2014, 31:1008-1017.

Naeser MA, Saltmarche A, Krengel MH, Hamblin, MR, Knight, JA. Improved Cognitive Function After Transcranial, Light-Emitting Diode Treatments in Chronic, Traumatic Brain Injury: Two Case Reports. (2011). Photomedicine and Laser Surgery, 29(5): 351-358, PMC3104287.

a) Sample LED cluster head, showing the side that was applied to the skin. The "X" shows the location of the 9 red diodes embedded within the LED cluster head. The 52 near-infrared (NIR) diodes surrounding the "X" are not visible to the eye. Each red/NIR LED cluster head had a 2.1-inch diameter, and the total power output was 500mW.

b) View of subject being treated, and example of three LED placement areas on the head from Set A (1st, 2nd, and 3rd LED placements described in Table 2). During each treatment, 6 LED cluster heads were used simultaneously (13 Joules/cm2, 10 minutes per LED placement). Immediately after treatment using the Set A LED placements, the LED cluster heads were moved to other placements on the scalp (Set B) for 10 minutes. The LED cluster heads were held in place with a soft nylon cap. Total treatment time per visit was 20 minutes; it was painless, noninvasive and nonthermal.


Figure 2. Near-infrared (810 nm) LED cluster heads placed on specific parts of the head to deliver photons to parts of the surface brain cortex areas that are damaged in dementia (parts of the Default Mode Network). In addition, a separate near-infrared (810 nm) diode is placed inside the nostril to deliver NIR photons into deeper areas of the brain (hippocampus areas), which are also damaged in dementia. (Photo courtesy of Vielight Co., Toronto.)


Margaret Naeser, PhD, VA Boston Healthcare System, Boston University School of Medicine

Scalp application of near-infrared (NIR) LED was recently reported to significantly improve cognition in a controlled pilot study conducted in Toronto with a small group of dementia patients (Saltmarche, Naeser et al., 2016). The LEDs were applied to the head, and this was hypothesized to deliver NIR (810 nm) photons to specific surface parts of the brain that are damaged in dementia. In addition, a single NIR diode was applied through the nostril to deliver photons to a different part of the brain damaged in dementia (hippocampus). Significant improvements (p<.03) were observed on the Mini Mental Status Exam and on the Alzheimer’s Disease Assessment Scale-cognitive subscale after 12 weeks of LED treatments. The patients required continued treatments after that time period (at home) to maintain earlier gains. Reduced outbursts of anger, better sleep, and less wandering behaviors were also reported. See Figure 2.

Saltmarche AE, Naeser MA, Ho KF, Hamblin MR, Lim L. Significant Improvement in Memory and Quality of Life after Transcranial and Intranasal Photobiomodulation: A Randomized, Controlled, Single-Blind Pilot Study with Dementia. Poster, Alzheimer’s Association International Conference, July 24-28, 2016, Toronto.

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Figure 3.  Dr. Kimberly Sullivan, Dr. Margaret Naeser, and Anthony Hardie (Veteran of Gulf War, Kuwait Theater) at the VA Boston Healthcare System show a Helmet that is lined with near-infrared LEDs. This Helmet is being used in a controlled study to learn if application of the near-infrared LEDs (830 nm) can be used to improve cognition in Veterans who have developed cognitive problems that are part of Gulf War Illnesses. (LED Helmet, Photomedex, PA)

Gulf War Illnesses

Margaret Naeser, PhD, VA Boston Healthcare System, Boston University School of Medicine

The Department of Veterans Affairs has funded a research study to investigate if scalp application of LEDs can improve cognition in Veterans who have developed Gulf War Illnesses.  These Veterans served in the Gulf War Theater in 1990-91. Approximately 25-30% of them have developed Gulf War Illnesses, which include, in part, problems with cognition, as well as musculoskeletal pain. These problems may be associated with poor mitochondrial function due to pesticide exposure and anti-nerve gas pills used while deployed there. The research is ongoing at this time. It is a controlled study using NIR LEDs that line a Helmet. See Figure 3.


Figure 4.  Example of the type of non-healing wounds on the foot, where red/near-infrared LED (or low-level laser, LLLT) is applied to promote healing. This approach is often needed in patients where skin ulcers on the foot are associated with diabetes.

Non-Healing or Hard-to-Heal Wounds

James Carroll,

The cost and suffering with hard-to-heal wounds is substantial. The prevalence of diabetic wounds, venous ulcers and pressure sores is increasing due to aging populations and the rise of diabetes. Many $ billions are spent every year on sophisticated wound dressings, and yet the scale of the problem increases.

The effect of photobiomodulation (PBM) therapy on wound healing (by red or NIR laser or LED) has been reported in 20 randomized controlled clinical trials (RCTs), but some of these are distributed across a wide range of etiologies and were smaller studies. The literature now extends to over 300 wound healing papers. Laboratory studies are unequivocal and consistent in reporting that PBM therapy improves the speed and quality of wound healing in a variety of animal models of compromised wound healing.

Clinical trial examples:

  • Gupta et al., (1998) performed an RCT with LED PBM Therapy applied to 12 venous leg ulcers. Treatment was applied three times a week for 10 weeks. At the conclusion of the study, the percentage of the initial ulcer area remaining unhealed in the placebo groups was 84.7% but only 24.4% in the PBM therapy group (P = 0.0008) [1].
  • Schubert et al., (2001) performed an RCT with LED PBM Therapy on pressure ulcers. 59 elderly patients  (> or =65 years) with Stage 2 or 3 skin ulcers. Treatment was applied 12 times in the first 4 weeks then weekly for a further 6 weeks. Results showed that wound closure was 55% faster in the treatment group than in placebo controls P<0.05 [2].
  • Kajagar et al., (2012) performed an RCT with LED PBM Therapy on diabetic foot ulcers in 68 patients over a period of just 15 days. Percentage ulcer area reduction was 40% in study group but only 12% in control group (p < 0.001) [3].

See Figure 4, for example of application of low-level laser (LLLT) or LED to treat non-healing wounds on the feet (as often is seen in diabetic patients).

1. Gupta, A.K., et al., The use of low energy photon therapy (LEPT) in venous leg ulcers: a double-blind, placebo-controlled study. Dermatol Surg, 1998. 24(12): p. 1383-6.
2. Schubert, V., Effects of phototherapy on pressure ulcer healing in elderly patients after a falling trauma. A prospective, randomized, controlled study. Photodermatol Photoimmunol Photomed, 2001. 17(1): p. 32-8.
3. Kajagar, B.M., et al., Efficacy of low level laser therapy on wound healing in patients with chronic diabetic foot ulcers-a randomised control trial. Indian J Surg, 2012. 74(5): p. 359-63.



Figure 5. Application of red and near-infrared light therapy to prevent or treat mouth sores (oral mucositis) in cancer patients receiving chemotherapy. Goggles are only worn if low-level laser is part of the therapy. When LEDs alone are used, no goggles are required.


Figure 6. Application of red and near-infrared light therapy to prevent or treat mouth sores (oral mucositis) in a child receiving chemotherapy for cancer. Goggles are only worn if low-level laser is part of the therapy.  When LEDs alone are used, no goggles are required.

Prevent Mouth Sores (Oral Mucositis) in Cancer Patients Undergoing Chemotherapy

James Carroll,

Oral mucositis is one of several painful cancer therapy side effects caused by chemotherapy, radiotherapy, or haematopoietic stem cell transplantation (HSCT). The pathophysiology includes inflammation and ulceration of mucosal tissues of the mouth, pharynx, and esophagus leading to the inability to eat and drink, and sometimes results in hospitalization for hydration or parenteral nutrition, which adds significantly to the cost of patient care. Standard care options for oral mucositis have limited benefits, and patients are frequently unable to tolerate the full dose and schedule of anticancer therapies.

The effect of photobiomodulation (PBM) therapy on oral mucositis (by low-level laser, LLLT, or LED) has been studied in over 30 randomized controlled clinical trials. Most of the studies are therapeutic (treating symptoms), but some clinical trials have shown treatment concurrent with cancer therapies can prevent or significantly reduce oral mucositis from occurring.

The Clinical Practice Guidelines of the Multinational Association of Supportive Care in Cancer and International Society for Oral Oncology (MASCC/ISOO) now recommends PBM therapy for the prevention of oral mucositits in HSCT recipients conditioned with high-dose chemotherapy, and also suggests treatment for patients treated with radiotherapy for head and neck cancer patients [1, 2].

Two recent PBM therapy review papers for cancer therapy side effects (including oral mucositis, dysphagia, xerostomia, hyposalivation, radiation dermatitis, osteonecrosis, lymphedema, etc.) summarize PBM mechanisms of action, discuss cancer safety considerations, and include PBM Therapy treatment protocols.[3, 4]

Figures 5 and 6 show patients being treated with red/near-infrared low-level laser (LLLT) or LED to prevent, or promote faster healing of, mouth sores in cancer patients undergoing chemotherapy.  The red/near-infrared treatments do not interfere with the cancer treatments in any way.

1. Migliorati, C., et al., Systematic review of laser and other light therapy for the management of oral mucositis in cancer patients. Support Care Cancer, 2013. 21(1): p. 333-41.
2. Lalla, R.V., et al., MASCC/ISOO clinical practice guidelines for the management of mucositis secondary to cancer therapy. Cancer, 2014. 120(10): p. 1453-61.
3. Zecha, J.A., et al., Low-level laser therapy/photobiomodulation in the management of side effects of chemoradiation therapy in head and neck cancer: part 2: proposed applications and treatment protocols. Support Care Cancer, 2016. 24(6): p. 2793-805.
4. Zecha, J.A., et al., Low level laser therapy/photobiomodulation in the management of side effects of chemoradiation therapy in head and neck cancer: part 1: mechanisms of action, dosimetric, and safety considerations. Support Care Cancer, 2016. 24(6): p. 2781-92.
5. Whelan HT, Connelly JF, Hodgson BD, et al. NASA Light-Emitting Diodes for the Prevention of Oral Mucositis in Pediatric Bone Marrow Transplant Patients.  Journal of Clinical Laser Medicine and Surgery. 2002. 20(6): p. 319-324.


Figure 7. Application of red/near-infrared LLLT and LED to treat neck pain.


Figure 8. Application of red/near-infrared LLLT and LED to treat the Achilles tendon.


Figure 9. Application of red/near-infrared LLLT and LED to treat the elbow (lateral epicondylitis).


Figure 10. Application of red/near-infrared LLLT and LED to treat low back pain.

Musculoskeletal Dysfunction and Pain

James Carroll,

Musculoskeletal pain and dysfunction is the leading cause of disability and far exceeds the cost of all other healthcare categories, including diabetes, heart disease, cancer, and all forms of dementia.

The positive effects of photobiomodulation (PBM) therapy on musculoskeletal pain and dysfunction (by low-level laser or LED) has been reported in over 120 randomized controlled clinical trials (RCTs). These include back pain, neck pain, tendinopathies (tennis elbow, shoulder tendinopathies, achilles tendinopathies), osteoarthritis, rheumatoid arthritis, ankle sprains, myofascial pain, TMJ pain, carpal tunnel syndrome, repetitive strain injuries and other soft tissue injuries, etc.

A Pubmed search for “pain” and PBM (and a range of alternative terms such as LLLT and laser biostimulation) returns 985 results. The effect of PBM therapy on pain has been explored more than any other clinical category and is by far the most common clinical application in medical practice today.

Many systematic reviews have been performed with the following conclusions.

Chow et al., 2009, The Lancet: “LLLT reduces pain immediately after treatment in acute neck pain and up to 22 weeks after completion of treatment in patients with chronic neck pain”[1]. 19913903

Glazed et al., 2016, Acupunct Med BMJ: “We demonstrated moderate quality of evidence to support a clinically important benefit in LLLT for chronic non-specific low back pain in the short term” [2]

Bjordal et al., 2003, Australian Journal Physiotherapy: “Low level laser therapy with the suggested dose range significantly reduces pain and improves health status in chronic joint disorders” [3]

Tumilty et al., 2009, Photomedicine and laser surgery: “LLLT can potentially be effective in treating tendinopathy when recommended dosages are used. The 12 positive studies provide strong evidence that positive outcomes are associated with the use of current dosage recommendations for the treatment of tendinopathy”[4]

Figures 7, 8, 9 and 10 show application of red/near-infrared low-level laser therapy (LLLT) or LED to treat pain in musculoskeletal injures (acute or chronic).

1.  Chow, R.T., et al., Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials. Lancet, 2009. 374(9705): p. 1897-908.
2.  Glazov, G., M. Yelland, and J. Emery, Low-level laser therapy for chronic non-specific low back pain: a meta-analysis of randomised controlled trials. Acupunct Med, 2016.
3.  Bjordal, J.M., et al., A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders. Aust J Physiother, 2003. 49(2): p. 107-16.
4.  Tumilty, S., et al., Low level laser treatment of tendinopathy: a systematic review with meta-analysis. Photomed Laser Surg, 2010. 28(1): p. 3-16.
5. Naeser MA.  Photobiomodulation of Pain in Carpal Tunnel Syndrome:  Review of Seven Laser Therapy Studies.  Photomedicine and Laser Surgery, 2006. 24(2): p. 101-110.


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