Poor Reliability of Concussion History in Athletes

Recent research has explored the long-term neurodegenerative effects associated with recurrent concussion in athletes. Findings from a number of former professional football players found that the number of concussions sustained during their professional careers was associated with the rate of diagnosed clinical depression and late-life cognitive impairment. A limitation of these studies was the use of a self-reported history of concussion.

Imperfect recall can generate bias in studies when the proportion of events recalled is associated with the health end points of interest (such as neurodementia or depression). Associations observed in these studies may be inaccurate if athletes differ in their knowledge and recognition of concussion symptomatology in a manner that is associated with the health outcome of interest. Taking depression as an example, if depressed athletes tend to overreport their concussions (or if nondepressed athletes tend to underreport their concussions), then the association between concussion and depression observed in these studies might be due to bias. Without data about the reliability of concussion self-report, there will always be a concern that the observed association between concussion and neurodementia/depression could be due to differential recall bias. Here is a copy of the abstract published in Med Sci Sports Exercise in 2012