The brain disorder, known as chronic traumatic encephalopathy (CTE), is marked by a buildup of abnormal proteins in the brain. It can cause memory loss, trouble concentrating, impulsive and erratic behavior, depression, and eventually dementia.
CTE is often compared to being "punch drunk," says Alexander P. Lin, PhD, an investigator at the Center for Clinical Spectroscopy at Brigham and Women's Hospital in Boston.
CTE can only be definitively diagnosed by autopsy. But in a study of five retired pro athletes, Lin and colleagues found that a specialized imaging technique called magnetic resonance spectroscopy may help diagnose CTE at an earlier stage.
Often called a virtual biopsy, "magnetic resonance spectroscopy samples brain tissue and measures brain chemistry," Lin tells WebMD. It's performed using a regular MRI scanner with software modifications.
The hope is that doctors can eventually diagnose CTE at any early stage so patients can change their behavior before lasting damage occurs, he says.
Brain Chemical Changes in Former Athletes
Lin and colleagues studied retired athletes -- three football players, a wrestler, and a boxer --- aged 32 to 55 who had suffered a number of concussions over a period of three to 15 years and five men of similar ages who hadn't suffered head trauma and had no cognitive problems. All underwent magnetic resonance spectroscopy.
"There were definite brain chemical changes in the [athletes]," Lin says.
Among the findings:
- Levels of choline, a marker of tissue damage, were 12.5% higher in the brains of former athletes than in the healthy volunteers.
- Levels of glutamate were 12% higher in the athletes. When glutamate levels are too high, brain cells die off, Li says.
- Levels of gamma-aminobutyric acid (GABA), a brain chemical involved in memory, were 8% lower in the former athletes than in the healthy volunteers.
The findings were presented at the annual meeting of the Radiological Society of North America.
Recreational Athletes, Military Personnel Can Be Affected Too
"While the findings are obviously very preliminary, we are starting to see chemical changes in the brains" of people who suffer repeated head blows, Lin says.