PROSPECTIVE-STUDY OF CENTRAL-NERVOUS-SYSTEM FUNCTION IN AMATEUR BOXERS IN THE UNITED-STATES

Active amateur boxers from six US cities were studied in 1986-1990 to determine whether changes in central nervous system function over a 2- year interval (as evaluated by tests of perceptual/motor function, att ention/concentration, psychomotor speed, memory, visuoconstructional a bility, and mental control, measures of ataxia and brainstem auditory evoked potentials, and electroencephalography) were associated with de gree of participation in amateur boxing. A total of 484 participants w ere examined at baseline; 393 (81.2%) were examined 2 years later. At baseline, 22% of the participants had not yet competed in a bout; 9% h ad never competed in a bout by the second examination. Exposure was de fined by number of bouts, sparring-years, and sparring with a professi onal boxer. Very few statistically significant odds ratios were found between exposure and change in function. Significant tests of trend we re found between the total number of bouts incurred before the baselin e examination and changes in memory, visuoconstructional ability, and perceptual/motor ability. The significant trends for change in functio n in the latter two domains were primarily due to performance on the B lock Design test, which was common to both test domains. No statistica lly significant associations were found between more recent bouts (aft er the baseline visit) and any functional domains, nor between bouts o r sparring and any other outcome measures. The significant trends with past bouts, but not more recent bouts, may reflect the need for a lon g latency period before effects are manifest. Alternatively, given cha nges in safety practices, the observed association may be related to m ore severe exposure from bouts that occurred before 1986, when new saf ety measures were imposed.