Pattern in PTSD brain activity

US researchers have discovered a distinct pattern of brain activity in people with post traumatic stress disorder that may give doctors an objective way to test for it, they said.

Using a brain imaging device called magnetoencephalography, which measures how the brain processes information, a team at the University of Minnesota and the Minneapolis VA Medical Centre found differences in brain activity between people with PTSD and healthy people.

Having a test for PTSD could speed treatment and simplify insurance coverage, said Dr Apostolos  Georgopoulos of the University of Minnesota, whose study appears in the Journal of Neural Engineering.

PTSD, an anxiety disorder sometimes caused by wartime trauma, can cause flashbacks, nightmares, anger or edginess. It currently is considered a "soft disorder," Georgopoulos said. "The thinking is people can suffer from it, but there is no biological marker."

How the study was done

Georgopoulos and colleagues studied 74 US veterans with PTSD and 250 people with no mental health problems.  They scanned the brains of study participants looking for a signal that might distinguish a PTSD patient from a healthy volunteer.

Georgopoulos said current imaging techniques, including magnetic resonance imaging or MRI and functional MRI, look at brain activity indirectly.

To get a direct measure, they used a highly sensitive magnetoencephalography or MEG devices, which measure the magnetic fields produced by electrical activity in the brain.

"What you get out of it is a signal that directly comes from brain activity," Georgopoulos said.

The scanner has 248 sensors that record the interactions in the brain on a millisecond by millisecond basis, much faster than current methods such as the functional magnetic resonance imaging or fMRI.

18.5% of troops suffer PTSD

These measurements allowed the team to spot biomarkers or signals in the brain scans of those who had PTSD. When they compared brain scans from PTSD and healthy volunteers, they could accurately pick out the PTSD patients 90% of the time.

"What you have in this disorder is a functional disruption of brain activity. This is what we pick up in an extremely highly accurate way," Georgopoulos said.

The team is now looking to confirm the findings in a study of 500 patients with PTSD and 500 healthy volunteers.

A study last year by the Rand Corp research organisation estimates that about 18.5% of the US troops sent to Iraq and Afghanistan show signs of either PTSD or depression, conditions linked closely with substance abuse. - (Reuters Health, January 2010)