Imaging shows structural changes in mild traumatic brain injury

Oct 25, 2007

Researchers report that diffusion tensor imaging can identify structural changes in the white matter of the brain that correlates to cognitive deficits even in patients with mild traumatic brain injury. The study is published in the October issue of the journal Brain.

"We studied patients with all severities of traumatic brain injury -- mild to severe -- and found that abnormalities in white matter existed on the spectrum," said Dr. Marilyn Kraus, associate professor of psychiatry and neurology at the University of Illinois at Chicago College of Medicine and lead author of the study. "Even in patients with mild TBI -- those identified as having minimal or no loss of consciousness -- there were structural deficits."

Diffusion tensor imaging uses magnetic resonance imaging technology to examine the integrity of white matter that is especially vulnerable to traumatic brain injury. This imaging modality allows researchers to quantify and qualify structural changes in white matter, particularly in chronic TBI patients.

Thirty-seven TBI patients (20 mild and 17 moderate to severe) and 18 healthy volunteers underwent diffusion tensor imaging and neuropsychological testing to evaluate memory, attention, and executive function. All subjects were at least six months post-injury, and the majority were high-functioning people who were employed or in school at the time of evaluation.

The researchers found that structural changes in the white matter correlate to observable cognitive deficits related to thinking, memory and attention. Patients with more severe injuries had greater white matter abnormalities, representing a permanent change in the brain.

"We know that discreet brain areas are important for specific types of functioning, such as thinking, memory, cognition and motor skills," said Kraus. "But what's also very important is that the white matter serves as the connection between these significant areas of the brain."

In some ways, the brain is similar to a computer, said Deborah Little, director of MRI research in the department of neurology and rehabilitation medicine at UIC and co-author of the study. "You have the CPU and the memory, but they are worthless unless they are connected to each other. The white matter of the brain has the same function as the cables of the computer."

When white matter is damaged, areas of the brain may appear healthy but they are actually "unplugged" and cannot function.

"This study validates that getting smacked in the head is not a good thing, despite the fact that some clinicians still believe a patient can recover fully after a concussion," said Little.

A significant percentage of patients in the study had no self-reported cognitive deficits, yet they did have permanent damage that was apparent to researchers.

TBI has been a long-standing public health problem and a significant source of disability, but the recent increase in veterans returning from war and athletes who have experienced multiple concussions has generated greater public attention to TBI.

"Very often in TBI there are forces being applied to the brain that stress the tracts of white matter -- pulling them, yanking them -- and the white matter becomes damaged," Kraus said.

Patients who have a contusion, or bruising of the brain, can also suffer from subtle and diffuse damage to the white matter. The researchers believe that not only the focal lesion but the damage to the white matter is very important.

In the study, the researchers were also able to determine axonal damage (tearing of the axons that allow one neuron to communicate with another) in white matter versus abnormalities in the myelin (the protective sheath that, if damaged, can disrupt signals between the brain and other parts of the body.) If an axon is severed, the damage generally cannot be repaired.

"We found that the milder injuries had less myelin damage, and the more severe injuries had both axonal and myelin damage," said Kraus.

"This research helps us to understand how early on, particularly in milder injuries, there may be some ability for myelin to repair," Little said. "When athletes, for example, are sustaining head injuries over and over -- without being told to sit out -- it may have a huge impact on their recovery. This could affect decisions clinicians make about when someone with a mild injury should return to the battlefield or playing field."

Source: University of Illinois at Chicago

Explore further: A new way to prevent the spread of devastating diseases

add to favorites email to friend print save as pdf

Related Stories

Bioengineers create functional 3-D brain-like tissue

Aug 11, 2014

Bioengineers have created three-dimensional brain-like tissue that functions like and has structural features similar to tissue in the rat brain and that can be kept alive in the lab for more than two months.

Body by smartphone

Jul 30, 2014

We love our smartphones. Since they marched out of the corporate world and into the hands of consumers about 10 years ago, we've relied more and more on our iPhone and Android devices to organize our schedules, ...

Saving the brain's white matter with mutated mice

Aug 17, 2010

Vanishing White Matter (VWM) disease is a devastating condition that involves the destruction of brain myelin due to a mutation in a central factor. To understand the disease and test potential treatments that could apply ...

Recommended for you

A new way to prevent the spread of devastating diseases

1 hour ago

For decades, researchers have tried to develop broadly effective vaccines to prevent the spread of illnesses such as HIV, malaria, and tuberculosis. While limited progress has been made along these lines, ...

New molecule allows for increase in stem cell transplants

2 hours ago

Investigators from the Institute for Research in Immunology and Cancer (IRIC) at the Université de Montréal have just published, in the prestigious magazine Science, the announcement of the discovery of a new molecule, the fi ...

Team explores STXBP5 gene and its role in blood clotting

4 hours ago

Two independent groups of researchers led by Sidney (Wally) Whiteheart, PhD, of the University of Kentucky, and Charles Lowenstein, MD, of the University of Rochester, have published important studies exploring the role that ...

User comments : 0