Whatever the cause of GWS, it is certainly not psychological, says Bernard Rosof of Huntington Hospital in New York, although no single cause is known. Suggested causes include exposure to low levels of sarin gas when chemical munitions were destroyed, and a drug called pyridostigmine bromide, which soldiers were given to protect them from sarin.
It's vital to find an objective test that will allow physicians to make a diagnosis, says James Baraniuk, an associate professor at MedStar Georgetown University Medical Center and one of the co-authors of the new imaging study.
To that end, Baraniuk and Georgetown colleague Rakib Rayhan examined 31 veterans with GWS, including Nichols. They scanned their brains using a technique called diffusion tensor imaging, which highlights the bundles of nerves, or white matter, connecting brain regions. They compared these to scans of 20 veterans who were not deployed in the Gulf.
The images indicate that in GWS, these nerve bundles break down and may have trouble forming connections, a phenomenon that has not been associated with any other illness. This suggests that the brain circuitry, rather than any specific brain area, is disrupted in people with the condition. Veterans with the worst symptoms tended to have the most pronounced abnormalities in their white matter.
The damaged areas tended to be in fibers that connect pain-registering nerves to higher brain centers responsible for interpreting pain. Another affected area was the ventral attention network, which allows people to break their concentration to respond to a stimulus. This fits with the affected veterans' tendency to be easily distracted and to have trouble with memory formation.
Because the number of people studied was small, it is not yet possible to draw a clear distinction between an affected brain and a normal brain, Baraniuk says. He next wants to look at similar scans of people with chronic fatigue syndrome or fibromyalgia, both of which share some symptoms with GWS.