Shortly after Waters' death, former Harvard defensive tackle and WWE wrestler Christopher Nowinski, whose wrestling career was ended by post-concussion syndrome and has since written a book about the dangers of concussions in contact sports, approached Waters' family and asked permission to have his brain tissue examined. After receiving permission, Nowinski had samples of Waters' brain tissue sent to neuropathologist Dr. Bennet Omalu at the University of Pittsburgh. Omalu believed, having examined the tissue, that Waters sustained brain damage from playing football: he went on to state that this led to Waters' depression. Omalu determined that Waters' brain tissue had developed chronic traumatic encephalopathy (CTE) and degenerated into that of an 80-year-old man with Alzheimer's disease, caused or hastened by the numerous concussions Waters sustained playing football.