Therapy that involves being exposed to blue light in the early morning can help in the healing process of people who have suffered mild traumatic brain injuries, such as concussion, researchers at the UA have found.
William D. “Scott” Killgore, psychiatry professor in the UA College of Medicine-Tucson, said the exposure to blue wavelength light each morning can help a person’s circadian rhythm so that people with mild brain injuries can get better, more regular sleep.
Killgore is the lead author on a new study published in the journal Neurobiology of Disease.
“This is likely true for everybody, but we recently demonstrated it in people recovering from mild traumatic brain injury, or mTBI. That improvement in sleep was translated into improvements in cognitive function, reduced daytime sleepiness and actual brain repair,” Killgore said in a news release from the University of Arizona.
“Mild traumatic brain injuries, or concussions, are often the result of falls, fights, car accidents and sports participation. ... Military personnel can also experience mTBI from exposure to explosive blasts,” Killgore said in the release.
“Your brain is about the consistency of thick Jell-O,” he said. “Imagine a bowl of Jell-O getting hit from a punch or slamming against the steering wheel in a car accident. What’s it doing? It’s absorbing that shock and bouncing around. During that impact, microscopic brain cells thinner than a strand of hair can easily stretch and tear and rip from the force.”
Those with a concussion 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, according to Killgore.
Headaches, attention problems, and mental fogginess are commonly reported after head injuries and can persist for some time.
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.
“About 50% of people with mTBI also complain that they have sleep problems after an injury,” Killgore said.
Recent research has shown that the brain repairs itself during sleep, so Killgore and his co-authors — John Vanuk, Bradley Shane, Mareen Weber and Sahil Bajaj, all from the Department of Psychiatry — sought to determine if improved sleep led to a faster recovery.
In a clinical trial, adults with mTBI used a cube-like device that shines bright blue light at participants from their desk or tables for 30 minutes early each morning for six weeks.
Control groups were exposed to bright amber light.
“Blue light suppresses brain production of a chemical called melatonin,” Killgore said. “You don’t want melatonin in the morning because it makes you drowsy and prepares the brain to sleep. When you are exposed to blue light in the morning, it shifts your brain’s biological clock so that in the evening, your melatonin will kick in earlier and help you to fall asleep and stay asleep.”
People get the most restorative sleep when it aligns with their natural circadian rhythm of melatonin — the body’s sleep-wake cycle associated with night and day.
“The circadian rhythm is one of the most powerful influences on human behavior,” Killgore said. “If we can get you sleeping regularly, at the same time each day, that’s much better because the body and the brain can more effectively coordinate all these repair processes.”
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 area of the brain responsible for visual attention.
“We think we’re facilitating brain healing by promoting better sleep and circadian alignment,” Killgore said in the release.
He 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.
