Post-traumatic stress is estimated to engulf more than 300,000 veterans of Iraq and Afghanistan, but until now, it's known as a "soft disorder" -- one without an objective biological path to diagnosis.

The researchers at the University of Minnesota and the Minneapolis VA Medical Centre have claimed that they have discovered a distinct pattern of brain activity among PTSD sufferers that will assist in confirming the disorder by measuring electromagnetic fields in the brain.

The researchers scanned the brains of 74 U. S. veterans with PTSD, and 250 civilians without the disorder, and claim that by observing specific brain biomarkers, they were able to accurately diagnose PTSD sufferers with 90 percent accuracy.

"This shows that PTSD is a brain disease", says Dr. Apostolos Georgopoulos, who led the research along with Brian Engdahl, and a team from the Brain Sciences Centre at the Minneapolis VA Medical Centre and University of Minnesota.

The MEG machines are a fast, sensitive, accurate and reliable method to measure electrical activity in the brain in contrast to conventional CT scans and MRIs.

The research is expected to revolutionize the military, which has been scrambling to address a surge in post-traumatic symptoms among newly returning vets.

In addition, the PTSD research develops on earlier work that cited that MEG could be used to diagnose Alzheimer's and multiple sclerosis in infected brains.