Eighteen former and active boxers underwent neurological examination, EEG, computed tomographic scan of the brain, and neuropsychological testing. Eighty-seven percent of the professional boxers had definite evidence of brain damage. All the boxers had abnormal results on at least one of the neuropsychological tests. Brain damage is a frequent result of a career in professional boxing.
Casson IR, Siegel O, Sham R, Campbell EA, Tarlau M, DiDomenico A. Brain Damage in Modern Boxers. JAMA. 1984;251(20):2663-2667. doi:10.1001/jama.1984.03340440021020