Low-level light therapy seems to impact the recovery of individuals with severe brain injuries. A study published in Radiology, a journal of the Radiological Society of North America (RSNA), found that low-level light therapy affects the healing process in the brains of those who have experienced significant brain injuries. The study suggests that lights of varying wavelengths, which have been investigated for their wound-healing abilities for many years, may have a positive impact on brain healing.MGH conducted a study using low-level light therapy on 38 patients with moderate traumatic brain injury. The patients received light therapy within 72 hours of their injuries through a helmet that emits near-infrared light. Dr. Rajiv Gupta, the co-lead author of the study, explained that the skull is transparent to near-infrared light, so once the helmet is on, the entire brain is exposed to the light. The researchers used functional MRI to measure the effects of the therapy.The study looked at the impact of light therapy on the brain’s resting-state functional connectivity, which is the communication between different brain regions when a person is at rest and not doing a specific task. The researchers used MRI results to compare three different recovery phases: the acute phase (within one week after injury), the subacute phase (two to three weeks post-injury), and the late-subacute phase (three months after injury).
Out of the 38 patients in the trial, 21 did not receive light therapy while wearing the helmet. This was done to provide a control group and minimize bias due to patient characteristics, as well as to avoid any potential issues.The placebo effects were examined in a study involving patients who underwent low-level light therapy. The research found that those who received the light therapy showed a greater change in resting-state connectivity in certain brain regions during the acute-to-subacute recovery phase. Nathaniel Mercaldo, a statistician from MGH and coauthor of the study, noted that there was an increase in connectivity within the first two weeks of receiving light treatment. However, the long-term effects of the treatment on brain connectivity are still uncertain, as no differences were detected between the two treatment groups in the long term.
The mechanism of action of light therapy on the brain is not yet fully understood. Previous studies suggest that it may involve changes to an enzyme in the mitochondria of cells, which are responsible for producing energy. This can lead to increased production of adenosine triphosphate, a molecule involved in storing and transferring energy within cells. Light therapy has also been associated with widening of blood vessels and anti-inflammatory effects.
“There is still much research to be done in order to fully understand the physiological mechanisms behind these effects,” said the co-author of the study.
The author of the article is Suk-tak Chan, Ph.D., a biomedical engineer at MGH.
Although there was an increase in connectivity for the patients who received light therapy during the acute to subacute phases, there was no noticeable difference in clinical outcomes between those who received treatment and the control group. The researchers believe that conducting additional studies with larger groups of patients and using imaging techniques beyond three months could help determine the therapeutic potential of light in treating traumatic brain injury.
The researchers anticipate that the role of light therapy will expand as more research results become available. The 810-nanometer-wavelength light used in the study is already being used in various therapeutic applications.The helmet is a safe and non-invasive treatment option that does not involve surgery or medications. It is also portable, allowing it to be used outside of a hospital setting. Dr. Gupta suggests that the helmet may be useful in treating various neurological conditions. He also mentions that it could potentially be beneficial in addressing disorders related to connectivity in psychiatry, such as PTSD, depression, and autism. The potential applications of light therapy in these areas are promising.
