BioEd Online

Regions of the brain important for thinking and memory may have shrunk in some veterans of the first Gulf War, according to a new study. The decline is at its worst in veterans who report more symptoms of what is commonly called 'Gulf War syndrome', the mysterious condition that has afflicted as many as one in seven veterans from the 1990-1991 war.

The finding, reported today in a poster at the American Academy of Neurology meeting in Boston, Massachusetts, results from a study of 36 veterans. The veterans were asked whether they had symptoms ranging from joint pain to memory loss. Neuropsychologist Roberta White of the School of Public Health at Boston University and her colleagues divided the respondents into two categories: those with more than five symptoms and those with five or less.

Magnetic resonance imaging of the two groups revealed that two regions of the brain — the overall cortex and the rostral anterior cingulated gyrus, areas known to be involved in thinking and learning — were 5% and 6% smaller, respectively, in the group experiencing more symptoms. Those same veterans scored 12% to 15% lower in memory tests.

White says the differences are not due to different levels of stress experienced by the veterans. But she can't tell whether the brain differences are from a pre-existing condition, or are the result of the veterans' time in the Persian Gulf. Nor can she tell from this study what, other than stress, might have caused this part of the brain to shrink. She next plans to look at brain shrinkage against levels of chemical exposure, to see whether the two are linked.

Stress, drugs and chemicals

Whether Gulf War syndrome has a physical basis has been a raging debate since the veterans first began returning home, complaining of illnesses ranging from digestive to memory problems.

The hunt was on to find the cause, with many attributing the ailment to psychological stress, and others fingering exposure to a chemical cocktail of potential neurotoxins including pesticides, low levels of chemical weapons, and even the drugs meant to protect against chemical weapons. "It has been an extremely controversial and emotional debate," says Robert Haley, an epidemiologist at the University of Texas Southwestern Medical Center in Dallas, who was not affiliated with the study.

White's analysis is the latest in a series of studies that have demonstrated some physiological differences in these veterans. There have been correlations between the severity of the symptoms and the extent of exposure to certain chemicals, for example, and veterans of the first Gulf War also have higher rates of the neurodegenerative condition Lou Gehrig's disease (amyotrophic lateral sclerosis).

But White says she thinks the public still perceives these illnesses as largely psychological. "I think the general feeling is that these guys just got more stressed out," says White. "But in every study I've done, I've controlled for stress and I've never been able to explain away my findings."

The debate has been frustrating and bewildering at times, says Haley, but it is also part of the normal scientific process. White's work is important, he says, because there are still relatively few studies that document physiological differences in the brain of Gulf War victims. It will take many reports such as these before the case for a physiological illness is firmly made, he says.

"Extraordinary conclusions require extraordinary proof," says Haley. "And the burden of proof is on those of us who hypothesize that this is a real brain illness."