Against a background of earlier neuropathological investigations demonstrating extensive histological and gross anatomical damage in boxers' brains,6,10,41 findings from the more recent neurobehavioral studies lend support to the concept of a continuum of brain injury which reflects the cumulative effects of repeated blows of subconcussive intensity and knockouts.5,35,38 The cumulative injury over a sufficient boxing experience may eventuate in progressive dementia, extrapyramidal, pyramidal, and cerebellar disorders, and personality changes in the most affected cases.6,9,16,41 In a study of 224 former boxers, Roberts35 found evidence of traumatic encephalopathy in 17% of the series.
The aforementioned studies implicate a high risk of neurobehavioral morbidity associated with extensive boxing experience, especially (but not exclusively) in professional bouts. However, these investigations were largely confined to ex-boxers who ranged in age up to 74 years,5,23,38 whereas relatively few boxers have been studied prospectively during the early stages of their amateur and professional careers.4,10,16 Although Casson, et al.,5 focused on boxers who were reportedly free of alcohol and drug abuse and other etiologies of neurological injury, some investigators21,32 have been less careful to exclude extraneous causes of neurobehavioral deficit. Variables such as sparring frequency, appropriateness of sparring partners and opponents, and intervals between bouts potentially contribute to morbidity.
Finally, utilizing published normative data to interpret neuropsychological test findings in boxers may introduce false-positive errors.5 It is questionable whether boxers are representative of the general population with respect to psychosocial variables. In a recent three-center study28 concerning outcome after mild head injury, significant geographic differences in neuropsychological performance were present across the samples of patients and their respective control groups despite apparent comparability in years of education. In the absence of suitably matched local control subjects, the investigators might have misinterpreted the data relative to the head-injured patients.
We have initiated a prospective longitudinal investigation of young amateur and professional boxers and a control group of amateur athletes matched on pertinent demographic variables. In this paper we report baseline and 6-month follow-up neuropsychological data on both groups and magnetic resonance imaging (MRI) findings in the boxers.
We are indebted to Lori Bertolino for assistance in testing the subjects and data analysis, to Beverly Parman and Liz Zindler for manuscript preparation, and to Dr. Arthur L. Benton and Dr. Barry Jordan for their critique of the paper. We are also grateful to the boxers who volunteered to participate in this investigation.
Roberts AH: Brain Damage in Boxers. A Study of the Prevalence of Traumatic Encephalopathy Among Ex-Professional Boxers. London: Pitman Medical and Scientific1969Roberts AH: Brain Damage in Boxers. A Study of the Prevalence of Traumatic Encephalopathy Among Ex-Professional Boxers.
This study was supported by a grant from the J.S. Aber-crombie Foundation and National Institutes of Health Grant NS-21889.
These data were presented in part at the World Medical Congress on Olympic Boxing in Reno, Nevada, on May 10, 1986.