Brain strain: Effect of autonomic dysreflexia on cerebral blood flow and cognition

Spinal cord injury (SCI) is a devastating chronic condition resulting not only in paralysis but severe autonomic cardiovascular dysfunction. In fact, cardiovascular disease is the leading cause of death in those living with SCI. Autonomic dysreflexia (AD) is a life-threatening condition characterized by episodes of extreme hypertension accompanied by pounding headaches, confusion, seizures, strokes and even death. Despite the high incidence of AD in individuals with cervical or high thoracic SCI and the negative impact this condition has on on the brain, there has been no prior studies examining the relationship between AD and cognition or cerebral blood flow.

Dr. Phillips’ research comprehensively examines cerebral blood flow during progressive AD and relates chronic AD severity to cognitive function. The vast majority of men with SCI experience sexual dysfunction and difficulty with ejaculation. Vibrostimulation is a standard medical procedure that helps with obtaining sperm for the purpose of family-planning. However, this procedure elicits AD in 96 percent of individuals with SCI above T6 and requires careful monitoring. Nonetheless, vibrostimulation offers a unique and ideal model through which it is possible to study the influence of AD on a number of cerebrovascular parameters.

As pilot data for this proposal, Dr. Phillips recorded spontaneously occurring AD bouts in individuals with SCI. In Project 1, Dr. Phillips will examine and measure cerebral blood flow during AD (induced by vibrostimulation) using Transcranial Doppler tests in the middle and posterior cerebral arteries, as well as a newly-developed volumetric technique using duplex ultrasound of the internal carotid and vertebral arteries. In Project 2, Dr. Phillips will examine the relationship between severity of AD (from 24 hour blood pressure monitoring) and cognitive function in SCI.

Ultimately, Dr. Phillips’ study will greatly contribute to the understanding of the cerebrovascular and cognitive effects of AD.