Tests Show Gulf War Vets Have Brain Damage, Not Stress

The new study, the first to compare the brain-related and psychological functions of ill and well veterans, found no evidence of psychological problems, including post-traumatic stress disorder or other stress-related illnesses.

"We comprehensively tested a broad range of brain-related function," said Hom, a clinical assistant professor of neurology. "The ill veterans performed worse on 59 of the 71 brain-related measures. Their psychological profile was similar to profiles of individuals with general medical problems and did not include psychopathology. Clearly, the ill veterans demonstrated a neuropsychological pattern of impairment that is indicative of generalized brain damage, not psychological reactions."

The study is part of the ongoing investigation at UT Southwestern into the illnesses reported by as many as 70,000 Gulf War veterans. It bolsters the researchers' conclusion, published in the Jan. 15 Journal of the American Medical Association, that some veterans are suffering from brain and nerve damage linked to their wartime use of flea collars, insect repellent and anti-nerve gas pills, as well as exposure to chemical nerve agents.

With a series of blinded epidemiological and clinical studies on veterans of the 24th Naval Mobile Construction Battalion, researchers identified a syndrome characterized by thought, memory and sleep difficulties; a second syndrome that involves more severe thought problems as well as confusion and imbalance; and a third syndrome of sore joints and muscles and tingling or numbness of the hands and feet.

The syndromes are variants of a rare disorder called organophosphate-induced delayed polyneuropathy, which is caused by exposure to certain chemicals that inhibit cholinesterase, an enzyme important to nervous system function.

The researchers said the cases' pattern of deficits in intelligence, problem-solving, attention and concentration, memory and learning, language, sensorimotor abilities and other brain functions is strikingly similar to those reported in a 1988 study of workers poisoned by organophosphate poisons in the work place.

"This study supports our overall theory that the syndromes we identified represent neurological damage from combinations of chemicals," said Dr. Robert Haley, who heads UT Southwestern's Gulf War syndrome research and is chief of epidemiology. "We developed the first case definition of Gulf War syndrome and this shows that our case definition is a marker for brain injury."

Haley, Hom and toxicologist Dr. Tom Kurt of the clinical faculty were the researchers involved in this phase of the University's ongoing search for a way of testing for the syndromes and eventually treating them.

Last year the team, working in collaboration with researchers at Duke University Medical Center, reported that combinations of DEET in insect repellent, chlorpyrifos (Dursban) in flea collars and the anti-nerve gas pills containing pyridostigmine bromide caused neurotoxicity in hens when given in two- or three-way combinations but not when given individually.

Results are published in the August Archives of Clinical Neuropsychology. The Perot Foundation provided funding for the studies.