LONDON (AP) — The degenerative damage potentially caused by repeated blows to the head in soccer has been highlighted by a rare study of brains of a small number of retired players who developed dementia.

Fourteen former players were part of the research that began around 40 years ago and six brains, which underwent post-mortem examinations, had signs of Alzheimer's disease.

Four brains were found to have chronic traumatic encephalopathy (CTE) pathology, a possible consequence of repeated impacts to the brain, including heading the ball. A previous study of 268 brains from the general populati...