Auditory distraction: event-related potential and behavioral indices

Objective: The aim of this study was to illuminate behavioral and event-rel ated potential (ERP) effects of attentional orienting and reorienting obtai ned in a newly developed auditory distraction paradigm, to provide more pre cise indicators about the neural generators of the ERP effects using scalp current density (SCD) analysis, and to evaluate the stability of the distra ction effects. Methods: In two sessions separated by 25 days, 10 subjects were presented w ith tones being of short (200 ms) and long (400 ms) duration equiprobably; tones were of high-probability standard or of low-probability deviant frequ ency. In Distraction condition, subjects had to behaviorally discriminate s hort from long tones. In Ignore condition, subjects were reading a book. Be havioral performance and multichannel EEG were recorded. Results: Task-irrelevant frequency deviations prolonged reaction times in t he duration discrimination task by more than 35 ms and elicited the MMN and P3a components of the event-related potential. The P3a was followed by a n egative deflection called RON (reorienting negativity). P3a and RON were ab sent in Ignore condition. All effects were found to be highly stable betwee n sessions (product-moment correlations between 0.76 and 0.90). SCD analysi s suggested frontal generators for P3a and for RON. Conclusions: It is demonstrated that small frequency deviations may yield d istinct distraction effects in a tone duration discrimination task on a beh avioral and on an electrophysiological level. Results support the hypothesi s that frontal areas are involved in the exogenous orienting of attention ( P3a) and in the reorienting of attention (RON). Due to the high stability o f the deviance-related behavioral and ERP effects, this distraction paradig m may be utilized for clinical research. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.