Barrow Neuroradiologist Links Concussion Symptoms to White Matter Injuries

A neuroradiologist at Barrow is using a magnetic resonance imaging technique known as diffusion tensor imaging to study the effects of concussion deep in the brain.

“Diffusion tensor MRI is a way to look at the white matter of the brain,” said Dr. Lea Alhilali. “The white matter is kind of like the cables that connect all of the different parts of the brain.”

The white matter is made up of nerve fibers called axons, which form the connections between nerve cells. The axons are protected by a fatty sheath called myelin, which facilitates the transmission of electrical signals between nerve cells.

Dr. Alhilali began looking at the white matter of the brain because she wanted to understand why symptoms vary widely in concussion patients.

“Is it just simply the way that each individual responds to the same injury, or does each person actually have different underlying injuries to the white matter?” she said.

Dr. Alhilali found that people who mainly experienced dizziness after a concussion had abnormalities in the white matter in the balance center of the brain, as well as the region that is responsible for 3-D vision. People who experienced sleep-wake disturbances and memory problems had abnormalities in the portion of the brain responsible for sleep onset and sleep-associated memory consolidation.

“We found that there are unique injuries underlying each unique post-concussive syndrome, and that we shouldn’t just think of concussion as a single diagnosis but rather an umbrella diagnosis that encompasses many different types of injuries,” she said.

Dr. Alhilali was quoted in a Scientific American article about a study published in the Canadian Medical Association Journal. The study found that a single concussion may triple the long-term risk of suicide.

We found that there are unique injuries underlying each unique post-concussive syndrome, and that we shouldn’t just think of concussion as a single diagnosis but rather an umbrella diagnosis that encompasses many different types of injuries.

-Dr. Lea Alhilali, Barrow Neuroradiologist

While she did not participate in the Canadian study, Dr. Alhilali found in her own research that people who experienced depression following a concussion had injury to the reward center of the brain.

“The patients in our cohort were very similar to those in the Canadian study,” she said. “They were patients who usually only had a single mild concussive injury. So, the idea that a single mild injury has significant impact on the neuropsychological circuits of the brain and in turn could lead to a higher risk of suicide is not surprising to me at all.”

Dr. Alhilali is using a mathematical equation known as Shannon entropy to measure the complexity of the white matter gathered from diffusion tensor imaging. Using this formula, she found that people who had a concussion had significantly less complex white matter than people who had not had a concussion. She also found that the less complex a person’s white matter was, the more symptomatic that person was.

“It’s kind of changing the way we look at imaging,” she said. “It’s changing from a subjective interpretation by a human that we traditionally think of with a radiologist to a more objective, computerized analysis of the data.”

photograph of a phillips research magnetic resonance imaging device used at barrow neurological institute
One of the research MRI machines used at Barrow.

She said this mathematical analysis will make it easier to determine whether a person actually has an organic brain injury due to concussion or if he or she is suffering from psychological effects related to the trauma – such as post-traumatic stress disorder, job loss, or the inability to play a sport.

Dr. Alhilali said these findings could help physicians target treatments for concussion patients.

“If we understand that different patients with different symptoms have different injuries, we can treat them appropriately,” she said. “If we group all patients with concussions together, we’re never going to find what treatment works best because we’re trying to use one treatment for different injuries.”

Dr. Alhilali said the fact that concussion was not recognized as a disease until recently is part of the reason there is still a lot to learn about it. She also said tools that are being used to study concussions, like diffusion tensor imaging, have not been available for long.

“It’s such a common disease, and it’s a disease that wasn’t even considered a disease 10 years ago,” she said. “I think it’s an incredible opportunity to make a significant contribution to medicine if you can help to understand the pathology.”

She said an important conclusion from her research for both physicians and patients is that concussions are serious and should never be ignored.

“Patients shouldn’t be afraid to bring their symptoms to the attention of a doctor, and a doctor shouldn’t be afraid to treat it like a real disease,” she said.