Concussions in military personnel and athletes reveal damage to sound processing : Shots

Researchers are studying athletes and military personnel to learn more about how movement can affect the brain’s ability to perceive sound.

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Researchers are studying athletes and military personnel to learn more about how movement can affect the brain’s ability to perceive sound.

Colsta Images / Getty Images / Image Source

Headaches, nausea, dizziness, and confusion are among the most common symptoms. But researchers say hitting the head can also make it difficult to understand speech in a noisy room.

“Making sense of sound is one of the hardest things we can do with our brains,” he says. Nina Kraus, Professor of Neurobiology at Northwestern University. “So you can imagine that a hesitation, a headache, really interferes with sound processing.”

Krauss says about 15% to 20% of hiccups cause persistent problems with sound processing, which shows that millions of people are affected each year in the United States, an even more common problem in the military, where Many soldiers who saw. Fighting in Iraq and Afghanistan has been damaged by roadside bombs.

From ear to brain

“Our perception of sound begins with the nerve cells in the inner ear that convert pressure waves into electrical signals,” Krauss said. But it takes a lot of brain power to translate these signals into the auditory world that we understand.

The brain needs to compare signals from two ears to determine the source of sound. Then it needs to keep an eye on changes in volume, pitch, time and other features.

Cross’s lab was called. Brain Volts, Is conducting a five-year study of 500 athletes at Elite College to find out how noise can affect the brain’s ability to process large amounts of auditory information. And he has dedicated an entire chapter to the connection in his 2021 book, Sound Brain: How our brain creates a world of meaningful sound..

Krauss says college athletes who maintain a vibe are usually heard – at least when it comes to detecting unconscious sounds. Yet they often fail at what is called the “Speech in Noise Test.”

“You have to listen to a player who is embedding a fast sound,” she says. Ordinary brain workers will be able to understand sentences even when there is a lot of noise in the background. But many of those who hesitate to recover will fail the test.

Hesitation can also leave athletes extremely sensitive to sounds.

To learn more, Cross’s lab is analyzing electrical signals in the parts of the brain that process auditory information.

“All you need to do is insert two electrodes into the scalp and stick some airbuds in a person’s ear and make some noises,” she says. Also requires some fancy tools, and requires a lot of skill. Explain the result.

From this point of view, it is possible to determine which sound-processing parts of the brain are affected by a head injury, even if the person being tested is asleep. “It gives you an objective way of assessing mental health,” says Krauss.

She says researchers are just beginning to understand how agitation affects brain circuits. But preliminary evidence suggests that brain injury causes “barriers” – preventing information from flowing rapidly from one part of the brain to another.

Krauss says most players recover from reluctance in a week or two. For people with long-lasting symptoms, she is experimenting with something called rhythm therapy, which has its roots in dance.

“Athletes need to hear sounds and move their whole body so that they can adapt to what they are hearing,” she says. The idea is to strengthen the pathways needed to process the sound.

The commotion from the bombings

The military has been studying the link between head injuries and sound processing since about 2005. Melissa PapishA research researcher at the National Center for Veterans Affairs for Rehabilitation Auditory Research in Portland, Ore.

During the Iraq and Afghanistan wars, she says, the VA began to see something strange in military personnel.

“We have a sudden influx of relatively young and middle-aged people,” she says. “They come to our audiology clinic and say, ‘Hey, I’m having trouble hearing.’

Except when Papish gets his hearing tested, it seems “basically normal.” Surprisingly, his ears are fine. But their minds cannot act on what they are hearing.

Like hesitant athletes, these patients have difficulty distinguishing speech from background noise. She says many people also find it difficult to act on a fast-spoken speech.

VA scientists knew that a wave of roadside bombs could cause a wave without causing any injuries. So they took a closer look at patients who had difficulty processing their voices, and found that many people had experienced one or more explosions.

Papish says some veterans still have auditory symptoms more than a decade after the bombing.

Now that most military personnel have left the battlefield, the VA is looking at another possible source of brain injury. This includes exposure to many small blast waves that pass through the brains of people who wield high-powered weapons or use explosives in training exercises.

“This will be a major area of ​​research in the future,” says Papish. The military “wants to stop this kind of thing before it becomes a permanent problem for veterans.”

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