WASHINGTON — Gulf War illness may have two distinct forms, depending on which brain regions have atrophied. That could help explain why clinicians encounter veterans with different symptoms and complaints, according to new research.
The study of Gulf War veterans was recently published in the online journal PLOS ONE.
Georgetown University researchers used brain imaging that was acquired before and after exercise tests to determine the effects of physical stress on the veterans and controls. In 18 veterans, they found that pain levels increased after completion of the exercise stress tests, with fMRI scans in these participants showing loss of brain matter in adjacent regions associated with pain regulation.
This same group, during cognitive tasks, showed an increased use of the basal ganglia — a potential compensatory strategy the brain uses that is also seen in neurodegenerative disorders such as Alzheimer’s disease. Those veterans lost the ability to employ their basal ganglia after exercise suggesting a physiological stressor had created an adverse response.
Yet, “a separate group of 10 veterans had a very different clinical alteration,” said lead author Rakib Rayhan, a Georgetown University researcher. Substantial increases in heart rate and atrophy in the brain stem occurred in those study subjects.
Alterations in cognition, brain structure and exercise-induced symptoms, found in the veterans, did not appear in the 10-participant matched control group, according to the researchers.
“The use of other brain areas to compensate for a damaged area is seen in other disorders, such as Alzheimer’s disease, which is why we believe our data show that these veterans are suffering from central nervous system dysfunction,” Rayhan explained.
Symptoms of Gulf War illness range from mild to debilitating and can include widespread pain, fatigue and headache, as well as cognitive and gastrointestinal dysfunctions.
“Our findings help explain and validate what these veterans have long said about their illness,” Rayhan said.
- Rayhan RU, Stevens BW,. Raksit MP, Ripple JA, et. al., Exercise Challenge in Gulf War Illness Reveals Two Subgroups with Altered Brain Structure and Function. PLoS ONE, 2013; 8 (6): e63903 DOI: 10.1371/journal.pone.0063903