FYI.

This story is over 5 years old.

Tech

Virtual Reality Reveals Why PTSD Victims Can't Remember Their Trauma

Recreating traumatic experiences might be one way to treat the disease.
Image: 807MDSC/Flickr

Breakthroughs in those suffering from PTSD often occur when a patient is able to talk through what happened in a calm way. Unfortunately, in many cases, they can't remember the specific details. Using virtual reality, scientists are well on their way to understanding why that is. And in the future, they might even use the technology to recreate the traumatic event to stimulate a victim's memory.

When something traumatic happens, in many cases, people feel disassociated with their bodies, and some report experiencing the event with a third-person view. That feeling is also common in patients with any number of mental illnesses, and patients often report not really remembering much of what happened during one of those experiences.

Advertisement

The Army is already experimenting with using virtual reality as exposure therapy, and studies at USC and Johns Hopkins University have also explored it as a treatment option. But, until now, there was no good way of figuring out why, exactly, people with PTSD experience memory loss. A new study published in Proceedings of the National Academies of Sciences suggests it might be impossible to form memories while having an out-of-body experience.

Henrik Ehrsson of Sweden’s Karolinska Institute designed an experiment where 84 students would take an oral quiz as given by an eccentric, old professor. Half of the students took the test while sitting in their “real” bodies, while the other half took the test while looking at the situation from a third-person perspective. Essentially, the VR goggles showed themselves sitting in the room with the professor as if it were a television show. A week later, the students were hooked up to an fMRI machine and asked to repeat back what they had experienced during the test—not necessarily questions and answers, but their feelings during the test, the professor’s actions, and the order in which events happened.

None of the 84 participants had a diagnosed mental illness, but even so, the group that had an “out of body” experience was barely able to remember anything.

“With a lot of mental illnesses, they don’t feel that they’re really located in their body, and these people have memory problems,” Ehrsson said. “It looks like at least part of the problem could be these dissociative states are associated with a weakened sense of experiencing the world at all.”

Ehrsson says that the fMRI scans showed that in both cases, students showed an increase in activity in the frontal lobe cortex, which is the part of the brain that’s activated when you’re trying to recall something, but that those who had an out-of-body experience showed very little activity in the hippocampus, which is where episodic memories are stored. Apparently, the “out of body” memories may be stored elsewhere, which is why recreating the experience might be so important to treatment.

That's why virtual reality treatment is so promising. If we can recreate the traumatic state in a safe way, patients might better be able to deal with it. At the moment, it’s too early to say whether this is going to lead to new treatment options for people suffering from mental illness, but the findings are an important step to better understanding what happens to the brain during an out-of-body experience.

"We don’t know if the out of body permanently damages memories at the moment of creation," Ehrsson said. "If that’s true, the memories are lost. But we think that memories that are created in an out-of-body state might just be created and stored in an unconventional way. We’re interested in seeing if, by reinstating the out-of-body illusion, would we be able to help people with PTSD remember the event in a more normal way.”