Distractibility after frontal lobe lesions: behavioral and event-related brain potential evidence

The authors used a semantic priming paradigm to investigate the distractibility phenomenon of patients with frontal lobe lesions (FLPs). They tested two distractibility categories: an inhibition category requiring inhibition of an automatic response and a distraction category caused by irrelevant, unexpected stimuli. Fifteen FLPs were compared with 2 matched control groups: 14 posterior-lesion patients and 15 normal controls. Both behavioral and event-related brain potential (ERP) measures were used. The results suggest that, although there were differences in performance between the FLP group and the control groups, there was no evidence that the FLPs had difficulty specifically with the inhibition category. The most consistent ERP result was that the FLP group had longer N100 latencies than either control group. On the basis of these results, the authors hypothesize that FLPs have difficulty focusing on and starting to process a new stimulus. The authors also discuss the unique contribution ERP evidence has made to cognitive studies.