Severe trauma affects kids' brain function, say Stanford/Packard researchers

The first study to examine brain activity patterns in severely traumatized children showed their brains function differently than those of healthy children, say researchers at the Stanford University School of Medicine and Lucile Packard Children's Hospital.

The study hints at the biological underpinnings of the disorder called PTSD, or post-traumatic stress disorder. It also provides a valuable benchmark with which to assess the effectiveness of potential therapies.

"Now we can see some real neurological reasons for the impulsivity, agitation, hyper-vigilance and avoidance behaviors that children with untreated PTSD often exhibit," said Victor Carrion, MD, child psychiatrist at Packard Children's. "The fact that their brains appear to be working differently may indicate a deficit for which other areas of the brain are trying to compensate."

Some children with PTSD, for example, cut or burn themselves as a way of coping with their feelings. The researchers found that affected children who had also cut or otherwise injured themselves exhibited unique patterns of activation in a portion of the brain involved in the perception of pain and emotions.

It's not yet clear whether the brain differences are caused by the interpersonal trauma, such as sexual or physical abuse, experienced by the children or if pre-existing differences make some children more susceptible to developing PTSD after traumatic events than their more resilient peers.

Carrion, who is also associate professor of psychiatry and behavioral sciences at the Stanford School of Medicine, is the lead author of the research, which was recently published online in the journal Depression and Anxiety.

The researchers used an experimental technique called functional magnetic resonance imaging, or fMRI, to compare brain activation patterns in 16 children with symptoms of PTSD with the patterns seen in 14 age- and gender-matched non-traumatized children as they performed a simple decision-making task. The fMRI analysis detects changes in blood flow and oxygenation that correlate with increased neuronal activity in different regions of the brain.

To conduct the test, study subjects were placed inside the fMRI machine - a body-sized, narrow, hollow tube - and then asked to push a button each time a letter other than X flashed on a screen in front of them. Because Xs were introduced only after a string of non-Xs, the test is a good way to measure what's known as response inhibition, or a subject's ability to suppress the natural tendency to push the button as soon as any letter appears. Response inhibition is often difficult for children and adults with PTSD.

MRI tests can leave some people feeling claustrophobic and frightened and the experience can be particularly difficult for children already struggling with past trauma. Carrion and his colleagues used a special "mock MRI" machine at Packard Children's to familiarize the study participants to the sights and sounds of the imaging procedure before conducting the real experiment.