Dr. Cárdenas is one of the foremost experts in the nation on traumatic brain injury and concussion. He is the founder of Barrow Concussion and Brain Injury Center at Dignity Health St. Joseph’s Hospital and Medical Center in Phoenix, the nation’s most comprehensive concussion prevention, treatment, and education program. Dr. Cárdenas is the only Arizona neurologist on the NFL’s Head, Neck and Spine Committee, where he advises the NFL on best practices for concussion prevention and management. Dr. Cárdenas is on the sidelines of every Arizona Cardinals and Arizona State University home football game to consult with players who may have a sustained a concussion. In addition, Dr. Cárdenas was instrumental in helping to create a new helmet protocol for the Arizona Interscholastic Association, which has since been adopted by the National Collegiate Athletic Association and the National Federation of State High School Associations. The rule states that every football player must return to the sidelines when their helmet comes off to have it inspected during the next play. The protocol has drastically decreased the number of helmets that have come off during the season.