The media have widely reported that retired NFL players are at risk for a neurodegenerative disorder called chronic traumatic encephalopathy (CTE), which causes symptoms such as aggression, depression, suicidality and progressive dementia.
But a study of retired NFL players, led by Christopher Randolph, PhD, of Loyola University Medical Center, has found no evidence to support this theory.
Randolph and colleagues report their findings in the Journal of the International Neuropsychological Society.
While there are no clearly defined diagnostic criteria for CTE, the condition has been suggested to be characterized by irritability, impulsivity, aggression, depression, short-term memory loss and heightened suicidal thinking or behavior.
Randolph and colleagues conducted a two-part study. The first part involved a telephone survey examining the prevalence of possible cognitive impairment in 531 retired NFL players over age 50. In the second part, researchers recruited a sample of players who appeared to have significant cognitive impairments, and examined them directly with neuropsychological testing.
The players who participated in the telephone survey had an average age of 64 and had played in the NFL for an average of 7.5 years. Thirty-five percent of this sample had possible cognitive impairment based on a screening interview known as the AD8.
A subsample of 41 retired NFL players were recruited for evidence of probable mild cognitive impairment. They underwent in-person neuropsychological assessments at the Center for the Study of Retired Athletes at the University of North Carolina, Chapel Hill. They then were compared with healthy controls and with non-athlete patients with a clinical diagnosis of mild cognitive impairment (MCI), commonly presumed to reflect the earliest stage of Alzheimer's disease.
While the retired NFL players were clearly impaired relative to healthy controls, the patterns of their impairments were virtually identical to those exhibited by the non-athletes with MCI.
"The retired NFL players basically look like regular patients who have mild cognitive impairment and have never played football," Randolph said.