Blue light could help heal mild traumatic brain injury

William Killgore/University of Arizona

Early morning blue light exposure therapy can aid healing for people impacted by mild traumatic brain injury (mTBI), according to new research from the University of Arizona and published in the journal Neurobiology of Disease.

Daily exposure to blue wavelength light each morning helps to re-entrain the circadian rhythm so that people get better, more regular sleep, according to William Killgore, PhD, lead author and psychiatry professor in the College of Medicine. In the randomized clinical trial, adults with mTBI used a cube-like device that shines bright blue light with a peak wavelength of 469 nanometers at participants from their desk or tables for 30 minutes early each morning for six weeks. Control groups were exposed to bright amber light.

As a result of the blue light treatment, participants fell asleep and woke an average of one hour earlier than before the trial and were less sleepy during the daytime. Participants improved their speed and efficiency in brain processing and showed an increase in volume in the pulvinar nucleus, an area of the brain responsible for visual attention. Neural connections and communication flow between the pulvinar nucleus and other parts of the brain that drive alertness and cognition were also strengthened.

Mild traumatic brain injuries, or concussions, are often the result of falls, fights, car accidents, and sports participation. Among other threats, military personnel can also experience mTBI from exposure to explosive blasts—shockwaves strike the soft tissue of the gut and push a burst of pressure into the brain, causing microscopic damage to blood vessels and brain tissue, Killgore said.

Those with a concussion or mTBI can momentarily see stars, become disoriented, or even briefly lose consciousness following the injury. However, loss of consciousness doesn't always happen and many people who sustain a concussion are able to walk it off without realizing they have a mild brain injury, said Killgore. Headaches, attention problems, and mental fogginess are commonly reported after head injuries and can persist for weeks or months for some people.

Few, if any, effective treatments for mTBI exist. The U.S. Army Medical Research and Development Command funded the research to find alternatives to medicinal methods of mTBI recovery.

Blue light from computers, smartphones, and TV screens often gives blue light a bad rap. But according to Killgore, when it comes to light, timing is critical.

“Light is not necessarily good or bad in-and-of-itself,” je said in a statement. “Like caffeine, it all comes down to when you use it. It can be terrible for your sleep if you're consuming coffee at 10 p.m., but it may be great for your alertness if you have it in the morning."

Killgore and his team plan to continue their research to see if blue light improves sleep quality and how light therapy might affect emotional and psychiatric disorders. Killgore believes that most people, whether injured or healthy, could benefit from correctly timed morning blue light exposure, a theory he hopes to prove for certain in future studies.