Veterans suffering from symptoms such as irritability, restlessness, hypersensitivity to stimulation, memory loss, fatigue and dizziness are often diagnosed with post-traumatic stress  disorder, traumatic brain injury (TBI) or both. According to the Department of Veterans Affairs, a new study shows PTSD and TBI register different brain activity in patients, and a common test may help doctors differentiate between the two.

The researchers used electroencephalograms (EEG), which are assessments that measure electrical activity in the brain. The size and direction of the brain waves can signal abnormalities. EEGs are commonly used to help diagnose conditions such as seizures, epilepsy, head injuries, dizziness, headaches, brain tumors and sleeping problems.

In this study, researchers analyzed a set of 147 EEGs given to Iraq and Afghanistan veterans. While comparing results, the researchers saw patterns of activity at different locations in the brain for TBI and PTSD. They saw brain waves moving slowly in opposite directions, likely coming from separate places in the brain.

The study’s lead researcher, Dr. Laura Manning Franke, a research psychologist at the Hunter Holmes McGuire VA Medical Center in Richmond, Va., said spotting distinct patterns of TBI and PTSD in separate parts of the brain can reduce the risk of confusing the two conditions and is key to helping improve diagnoses and treatments for veterans.

“That’s the holy grail,” said Franke. “We want to use the EEG to differentiate the problems, but also to predict recovery and be able to measure how people are doing in a more biological way than just measuring symptoms, although those are still relevant. But symptoms are also problematic because they’re influenced by so many things that aren’t the disease that we’re interested in.”

Franke added that while the research is promising, a larger number of veterans need to be tested to get more definitive results.