Blood Pressure, Cerebral Blood Flow and Cognition in Spinal Cord Injury

Following spinal cord injury autonomic regulation of the cardiovascular system is impaired, which results in a variety of measurable abnormalities in blood pressure. Evidence of causality has been documented in the general medical literature with findings of improved cognitive function following acute increases in blood pressure using the anti-hypotensive agent Midodrine Hydrochloride (midodrine). Additionally, a recent report documented an inverse association between blood pressure and depression suggesting that low blood pressure may confer greater risk than high blood pressure. Midodrine is a drug approved by the Food and Drug Administration to treat low blood pressure in the general population. Midodrine is not approved in the United States to treat low blood pressure in persons with spinal cord injury. Therefore, its use in this study is investigational. The first objective is to characterize the relationship between blood pressure, cerebral blood flow velocity and cognitive function after a single dose of midodrine compared to placebo. Second objective is to determine the long-term safety and efficacy of midodrine administration.