Prefrontal brain asymmetry and aggression in imprisoned violent offenders.

Anterior brain asymmetry, assessed through the alpha and beta band in resting-state electroencephalogram (EEG) is associated with approach-related behavioral dispositions, particularly with aggression in the general population. To date, the association between frontal asymmetry and aggression has not been examined in highly aggressive groups. We examined the topographic characteristics of alpha and beta activity, the relation of both asymmetry metrics to trait aggression, and whether alpha asymmetry was extreme in anterior regions according to clinical standards in a group of imprisoned violent offenders. As expected, these individuals were characterized by stronger right than left-hemispheric alpha activity, which was putatively extreme in anterior regions in one third of the cases. We also report that in line with observations made in the general population, aggression was associated with stronger right-frontal alpha activity in these violent individuals. This suggests that frontal alpha asymmetry, as a correlate of trait aggression, might be utilizable as an outcome measure in studies which assess the effects of anti-aggressiveness training in violent offenders.