Sport is not always healthy: Executive brain dysfunction in professional boxers FRANCESCO DI RUSSO AND DONATELLA SPINELLI Department of Education Sciences for Motor Activity and Sport, University of Rome ‘‘Foro Italico,’’ Rome, Italy, and Laboratory of Neuropsychology, Santa Lucia Foundation (IRCCS), Rome, Italy Abstract We measured ERPs of professional boxers in a Go/No-Go task, comparing them to fencers and non-athletes. Results showed that fencing improved attention and motor response control, but boxing did not. More strikingly, in boxers, as in brain trauma patients, the P3 component was delayed and reduced. The P3 delay of boxers was correlated with the amount of performed sport exercise. Furthermore, in terms of behavior, boxers showed increased intra-individual variability and switch cost. Results were consistent with the hypothesis of specific impairment at the level of response inhibition processing. We suggest that this impairment is derived from the cumulative effect of blows to the head. The changes found in boxers suggest that ERPs and reaction times may be a tool for early detection of specific brain dysfunction. Descriptors: Brain trauma, ERPs, Executive control, Sport, Boxing Practicing sport is one of the best activities for promoting mental and physical health; however, it can carry risks. The present study investigated athletes practicing the traditional discipline of boxing. It is well known that in severe cases, brain injury from repet- itive head blows in boxers may result in dementia pugilistica and parkinsonism. However, it is also relevant to evaluate cases that are much less severe and more frequent, such as cumulative ef- fects of non-severe head injuries in young and healthy boxers. The evidence of traumatic brain injury (TBI) in the boxer pop- ulation is still controversial (Loosemore, Knowles, & Whyte, 2007). Mild effects of concussion are difficult to detect with computed tomography (CT) or conventional magnetic reso- nance imaging (MRI); for instance, Haenel and colleagues (2008) reported a statistically non-significant prevalence of cerebral mi- cro-hemorrhages in boxers. Only the use of a technique more sensitive to micro-structural changes (diffusion tensor imaging [Chapell et al., 2006]) revealed diffuse brain damage in professional boxers. This brain damage involved both white and grey matter, and was more evident in professional boxers than in amateur boxers due to greater exposure to injury by professionals. Electrophysiology may prove to be a more sensitive technique than conventional MRI for showing effects of sports concus- sions. In symptomatic and asymptomatic hockey and football players, concussions seem to produce deficits both at the early and late stages of neural processing as indicated by N1, P2, and P3 amplitude reduction in an auditory oddball task (Gosselin, Theriault, Leclerc, Montplasir, & Lasonde, 2006). Modifications limited to the P3 component were described by other authors. In a visual oddball task, the P3 amplitude varied inversely with the severity of post-concussion symptoms in asymptomatic concussed athletes (Lavoie, Dupuis, Johnston, Leclerc, & Lassonde, 2004). P3 suppression was long-lasting: three years after the event, multi-concussed athletes showed P3 amplitude suppression while the N2pc component was intact (de Beau- mont, Brisson, Lassonde, & Jolicoeur, 2007). Even 30 years after concussion, effects on amplitude (and latency) of P3a and on latency of P3b were detected in an auditory oddball task (De Beaumont et al., 2009). To date, electrophysiological studies on boxers have been few and inconclusive. Thomasse, Jul- Jensen, de Fine Olivarius, Braemer & Christensen (1979) exam- ined the electroencephalograms (EEGs) of a large number of former champion amateur boxers with those of a control group consisting of former football players, and no difference was found. McLatchie et al. (1987) found that 8 of 20 amateur boxers had abnormal EEGs as determined by slow activity or a dominant 7 Hz rhythm. In an event-related potential (ERP) study of attention and orienting reaction in boxers before and after a fight, Breton, Pincemaille, Tarriere, & Renault (1991) found no abnormalities of attention or detection pro- cesses. However, a slight deficit was observed in the orienting reaction toward stimuli delivered to the right ear, an effect that was related to a greater number of blows delivered on the left side of the head. In the present study, we investigated the brain activity and reaction time (RT) of boxers using a Go/No-Go task. We selected this task for two reasons. First, it seems appropriate Support was provided by PRIN 2007 MIUR grant. Thanks to M. Di Serafino for his contributions to subject recruitment. Address reprint requests to: Prof. Francesco Di Russo, University of Rome ‘‘Foro Italico,’’ Largo Lauro De Bosis, 15, 00194 Rome, Italy. E-mail: francesco.dirusso@iusm.it Psychophysiology, ]]] (2009), 1–10. Wiley Periodicals, Inc. Printed in the USA. Copyright r 2009 Society for Psychophysiological Research DOI: 10.1111/j.1469-8986.2009.00950.x 1