Effects of Low-Level Exposure to Sarin and Cyclosarin During the 1991 Gulf War on Brain Function and Brain Structure in US Veterans

Potentially more than 100,000 US troops may have been exposed to the organophosphate chemical warfare agents sarin GB and cyclosarin GF when a munitions dump at Khamisiyah, Iraq was destroyed during the Gulf War GW in 1991. Although little is known about the long-term neurobehavioral or neurophysiological effects of low-dose exposure to GBGF in humans, recent studies of GW veterans from the Devens Cohort suggest decrements in certain cognitive domains and atrophy in brain white matter occur individuals with higher estimated levels of presumed GBGF exposure. The goal of the current study is to determine the generalizability of these findings in another cohort of GW veterans with suspected GBGF exposure. Neurobehavioral and imaging data collected in a study on Gulf War Illness between 2002-2007 were used in this study. We focused on the data of 40 GW-deployed veterans categorized as having been exposed to GBGF at Khamisiyah, Iraq and 40 matched controls. Magnetic resonance images MRI of the brain were analyzed using automated and semi-automated image processing techniques that produced volumetric measurements of gray matter GM, white matter WM, cerebrospinal fluid CSF and hippocampus. GW veterans with suspected GBGF exposure had reduced total GM and hippocampal volumes compared to their unexposed peers p0.01. Although there were no group differences in measures of cognitive function or total WM volume, there were significant, positive correlations between total WM volume and measures of executive function and visuospatial abilities in veterans with suspected GBGF exposure.