Blue light may aid recovery after concussion

Mild traumatic brain injury (mTBI), or concussion, can result from a range of causes, from a car accident to fights, falls, or sports. 

Following such an injury, people might see stars, become disoriented, or even lose consciousness briefly, but many come round without realizing that they have been concussed at all. 

However, for some, mTBI can result in weeks or months of symptoms, including headaches, mental fogginess, dizziness, memory loss, fatigue, and disturbed sleep. According to the researchers behind the current study, some 50% of people with mTBI complain of chronic sleep problems after the injury, which affects their ability to think and recover. 

And 15% of those with mTBI have symptoms that last for at least 1 year. 

Scientists believe that these symptoms occur due to the stretches and tears that the impact inflicts on microscopic brain cells. 

“Your brain is about the consistency of thick Jell-O,” explains lead author William D. “Scott” Killgore, a psychiatry professor at the University of Arizona in Tucson. “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.”

Such injury can also occur during explosive blasts, when shock waves hitting the soft tissue of the gut push a surge of pressure into the brain, damaging blood vessels and brain tissue. 

“Mild traumatic brain injury (mTBI), which is commonly known as concussion, is one of the most common injuries experienced by military personnel and is a major health concern worldwide,” Killgore told Medical News Today.

Sleep as a healer

“At present, there are virtually no effective treatments for concussion,” said Killgore. “We sought a nonpharmacologic (or nondrug) method to help people.” 

Killgore and his research team received funding from the U.S. Army Medical Research and Development Command to conduct the study, which features in the journal Neurobiology of Disease. 

The solution that they set out to prove effective was sleep. 

“Because sleep is so important for brain health and recovery, we reasoned that improving sleep timing and duration could lead to a more rapid recovery from mTBI,” said Killgore. “Considerable evidence suggests that sleep is important for brain repair processes,” he added. 

Killgore explained that scientists have shown that following an injury, sleep facilitates the production of new insulating brain cells called oligodendrocytes. 

“Without sufficient restorative sleep, the repair of brain tissue will likely be slowed or incomplete,” Killgore said.

Blue light in the morning

The recent clinical trial, which involved 32 adults with mTBI, focused on solidifying the participants’ circadian rhythm — the natural process that dictates our 24 hour sleep-wake cycle. 

The researchers achieved this by exposing the participants to blue light from a cube-like device for 30 minutes early each morning for 6 weeks. The participants in the control group used amber lights instead of blue.

Scientists have shown that blue light suppresses the brain’s production of melatonin, a chemical that makes us sleepy. 

“Blue light is one of the brain’s primary timekeepers,” explained Killgore. “Exposure to blue light, such as sunlight at sunrise, tells the body that it is morning and time to stop sleeping. That makes you more alert during the day and starts the clock ticking to tell you when to go to sleep later.” 

By using blue light, the participants reset the brain’s inner clock, helping participants fall asleep earlier and stay asleep. The most restorative, and therefore beneficial, sleep occurs when it is in tune with the body’s innate circadian rhythm. 

On average, participants using the blue light therapy fell asleep and woke up 1 hour earlier than before the trial and were less drowsy during the day. Their brain-processing speed and efficiency were improved, and they showed an increase in visual attention.