Using magnetoencephalography (MEG), researchers in the US have identified a biological marker in the brains of people with symptoms of post-traumatic stress disorder (PTSD), introducing for the first time a way of diagnosing the condition objectively, something that conventional brain scans like X-ray, CT, or MRI have failed to do.

A paper about the work is due to appear in the February issue of the Journal of Neural Engineering and was made available online on 20 January. The researchers are from the University of Minnesota and Minneapolis VA Medical Center.

We usually hear of PTSD occuring during combat situations, but it can result from any kind of traumatic event. A person with PTSD experiences flashbacks, recurring nightmares, intense feelings of anger, or hypervigilance, a sort of permanent state of “red alert” as if another traumatic event is going to happen any moment.

The study, which was funded by the US Department of Veterans Affairs, was led by Drs Apostolos Georgopoulos and Brian Engdahl, both members of the Brain Sciences Center at the Minneapolis VA Medical Center and University of Minnesota.

For the study, the researchers enrolled 74 US veterans with PTSD and 250 people with clean mental health and scanned them using magnetoencephalography (MEG), a non-invasive way of measuring magnetic fields in the brain.

The MEG showed a 90 per cent accuracy in differentiating the people with PTSD from the healthy subjects.

The MEG has 248 sensors that pick up millisecond by millisecond changes in interactions in the brain, a much more sensitive scanning resolution than current methods like functional magnetic resonance imaging (fMRI), which work on a second by second basis.

The researchers wrote that they used a “synchronous neural interactions (SNI) test which assesses the functional interactions among neural populations derived from magnetoencephalographic (MEG) recordings”, and referred in their paper to work published in September 2007 where they described how they used the same test to successfully detect brain diseases such as Alzheimer’s and multiple sclerosis.

As well as diagnosing those with PTSD, the researchers were also able to estimate the severity of their condition, suggesting that MEG may be also be useful in assessing patients affected by other brain disorders.

Georgopoulos told the media that:

“These findings document robust differences in brain function between the PTSD and control groups that can be used for differential diagnosis and which possess the potential for assessing and monitoring disease progression and effects of therapy.”

The next step will be to replicate the findings with a larger group of participants.

“The synchronous neural interactions test as a functional neuromarker for post-traumatic stress disorder (PTSD): a robust classification method based on the bootstrap.”
A P Georgopoulos, H-R M Tan, S M Lewis, A C Leuthold, A M Winskowski, J K Lynch and B Engdahl.
J. Neural Eng., 7 No 1 (February 2010) 016011 (7pp).
Published online 20 January 2010.
DOI:10.1088/1741-2560/7/1/016011

Source: University of Minnesota.

Written by: Catharine Paddock, PhD