William Walker, MD, is the Ernst & Helga Prosser Endowed Professor in PM&R/CERSE, and Associate Chair of Clinical Care, and Medical Director of Outpatient TBI Programs in the Department of PM&R, VCU School of Medicine. He is National Chair and Site PI for the LIMBIC-CENC National Multicenter Prospective Longitudinal study. Dr. Walker is site PI for the Virginia TBI Model System Form I and II study, and TBI Model System Collaborative study, Characterization and Treatment of Chronic Pain after Moderate to Severe TBI. Dr.