One Step Closer to Brain Imaging for PTSD Diagnosis

Researchers at Duke University have performed a series of short-term memory tasks in soldiers with and without post-traumatic stress disorder (PTSD), progressing one step further to the possibility of one day using brain scans to diagnose the illness. While performing the tasks, fMRI was used to examine the soldiers’ brains, in order to see how well they stay focused, a task that is more difficult for those with PTSD.

All of the 42 American soldiers—a little more than half of whom were men—examined in the study served in Iraq or Afghanistan and saw similar levels of combat; 22 had developed PTSD.

In the study, the soldiers were shown pictures of three similar faces, and then, after a short delay, another photograph of a face, which they had to identify as new or old according to the three other photographs they had just seen. About two seconds into the delay period, the soldiers were shown two completely different photographs—combat scenes from Iraq or Afghanistan, such neutral photos as a man playing an instrument, or two digitally altered photos that actually depicted nothing.

After a brief break to allow the brains of the participants to return to normal, the test was repeated 40 times. In looking at the dorsal lateral prefrontal cortex, associated with one’s focus, the research team discovered that the traumatic photos were far more distracting to the individuals without PTSD than their neutral counterparts, whereas the group with PTSD was equally distracted by both sets of photographs. In addition, participants with PTSD were less likely to correctly identify whether the second group of photos were new or old, regardless of whether those photos were traumatic.

Study findings also show that when the group with PTSD was shown the traumatic photos, the medial prefrontal cortex, associated with one’s sense of self, became much more active. Further, combat photos produced much more of a response in the amygdala, associated with processing of emotions, in the PTSD group when compared to the soldiers without PTSD, a finding consistent with results of previous research.

“This sensitivity to neutral information is consistent with the PTSD symptom of hypervigilance, where those afflicted are on high alert for threats and are more distracted by not only threatening situations that remind them of the trauma, but also by benign situations," said Dr. Rajendra Morey, the study’s lead author, assistant professor of Psychiatry, Duke University, and director, neuroimaging lab, Durham Veterans Administration Medical Center. "This has not been seen at the brain level before. If further research confirms this preliminary finding, this pattern could be useful in distinguishing the PTSD brain."

The study was also presented at the World Psychiatric Association congress, "Treatments in Psychiatry," by Dr. Florin Dolcos, assistant professor of Psychiatry and Neuroscience, University of Alberta, Edmonton, Canada.