[Chronic traumatic encephalopathy: an old acquaintance in athletes].

• Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease caused by repetitive head injuries like those seen in sports such as boxing, American football and soccer.- The clinical features of CTE are a range of cognitive, psychiatric and motor symptoms, and histopathology involves deposits of hyperphosphorylated tau protein and the presence of TAR DNA-binding protein (TDP-43) with relatively little beta-amyloid.- CTE is difficult to differentiate clinically from Alzheimer's disease, frontotemporal dementia and psychiatric disorders because of the major symptom overlap between these conditions.- The most important risk factors for developing CTE are the cumulative effect of repetitive head injuries, with or without clinical symptoms, and the duration of exposure to the repetitive injuries (the sporting career).- There is no treatment for CTE at present and the strategy must be primarily geared to prevention.- In view of the large number of people, including those in the Netherlands, who take part in sports in which head injuries may occur, research into CTE is of major societal importance.