Consequences of Traumatic Brain Injury in Professional American Football Players: A Systematic Review of the Literature.

OBJECTIVE: The purpose of this study was to systematically review the literature for the consequences Traumatic brain injury (TBI) has on cognitive, psychological, physical, and sports-related functioning in professional American Football players.

DATA SOURCES: We performed a systematic search in 2 databases, PubMed and SPORTDiscus, to obtain literature from January 1990 to January 2015. To be eligible for inclusion, a study had to examine the relationship between TBI and the consequences for several aspects of functioning in professional American football players older than 18 years. Methodological quality was assessed using a 5-item checklist which assessed selection bias, information bias, and correct reporting of the population and exposure characteristics.

MAIN RESULTS: The search yielded 21 studies that met our inclusion criteria. An evidence synthesis was performed on the extracted data and resulted in 5 levels of evidence. The evidence synthesis revealed that there is strong evidence that concussions are associated with late-life depression and short-term physical dysfunctions. Evidence for the relationship between concussion and impaired sports-related function, prolonged reaction time, memory impairment, and visual-motor speed was inconclusive. Moderate evidence was found for the association between TBI and mild cognitive impairment (MCI), and limited evidence was found for the association between TBI and executive dysfunction.

CONCLUSIONS: There is strong evidence that a history of concussion in American football players is associated with depression later in life and short-term physical dysfunctions. Also cognitive dysfunctions such as MCI are seen in older players with a history of TBI. These results provide input for actions to prevent TBI and their consequences in (retired) American football players.