There is a rapidly growing population of more than 5.3 million persons living with traumatic brain injury (TBI) in the United States. The economic and social impact of TBI within the United States is noteworthy. Occupation and social reintegration can be affected by medical complications that require rehospitalization. TBI impacts the central nervous system (CNS) and numerous other organ systems due to the traumatic mechanistic nature of injury, such as motor vehicle accidents, falls, and so on. Hydrocephalus and seizures appear to particularly have an impact on the long-term medical status of people with TBI. One of the most frequently asked questions by those affected by TBI is the impact that TBI has on life expectancy. As the brain ages, there is some softening and loss of cerebral tissue (i.e., encephalomacia). Cognitive changes occur as part of normal aging. The concept of reserve is particularly relevant when attempting to understand the interplay between TBI and neurological disorders associated with aging.