(GWI Brain) Autonomic dysfunction, brain blood flow, and cognitive decline in Veterans with Gulf War Illness

Gulf War Illness (GWI) is a multi-symptom disease in which cognitive complaints are common. Changes in cerebral blood flow regulation may explain some of the cognitive complaints associated with GWI. Currently, the long-term effects of GWI on cerebral blood flow regulation, and how this is affected by advancing age, is poorly understood. This makes it difficult to differentiate normal age-associated physiological changes from pathophysiological changes caused by GWI. In addition, previous work often evaluates physiological variables at rest. In this multi-symptom disease, pathophysiological differences are only revealed when the system is placed under tolerable physiological stress. It is possible that Veterans with GWI may demonstrate reductions in cerebral blood flow responses to physiological stressors, which may underlie their cognitive symptoms. Along these lines, GWI appears to be a condition characterized by accelerated brain aging, as evidenced by early neurodegeneration. This accelerated brain aging places Veterans with GWI at greater risk for developing AD and other dementias. Thus, interventions that improve the function of the cerebral blood vessels, increase neurovascular coupling, and prevent or delay neurodegeneration are critical for the long-term brain health of Veterans with GWI.
Cerebral blood flow responses and autonomic function will be measured in Veterans with and without GWI. We will investigate associations between cerebral blood flow regulation and autonomic function variables with neuroimaging biomarkers of cognitive decline. This study will consist of 4 visits: 1) Screen visit to determine eligibility; 2) Exercise test to determine aerobic fitness; 3) Laboratory visit for autonomic function testing; and 4) MRI visit to measure brain structure and cerebral vasoreactivity and neurovascular coupling.