OBJECTIVE: The present study addresses the question of whether behavioral and electrophysiological effects obtained with the auditory distraction paradigm proposed by Schröger et al. [Clin Neurophysiol 2000;111:1450] depend on the timing of stimulus occurrence. METHODS: Subjects had to discriminate the duration of tones. Occasionally, task-irrelevant frequency changes were used as distractors. In 3 experiments the stimulus onset asynchrony (SOA) was manipulated: In Experiment 1, SOAs of 1500, 2000 and 3000 ms were used in separate blocks; in Experiment 2, 5 different SOA of lengths between 1300 and 2500 ms were used within the blocks; in Experiment 3, a constant SOA of 1400 ms was compared with a SOA of random lengths between 1300 and 1500 ms. Performance data was analyzed for distraction effects. Event-related potentials (ERPs) were examined for deviance-related components, i.e. the mismatch negativity (MMN), the P3a and the re-orienting negativity (RON). RESULTS: Behavioral distraction effects were obtained in all experimental conditions. The electrophysiological data show MMN, P3a and RON for the deviating tones in all experimental conditions as well. CONCLUSIONS: The behavioral and electrophysiological deviance-related effects were not sensitive to the SOA manipulations. Therefore, the timing of the presentation can be adjusted to the proficiency level of the population to be tested without loosing the distraction effects.
OBJECTIVE: The present study addresses the question of whether behavioral and electrophysiological effects obtained with the auditory distraction paradigm proposed by Schröger et al. [Clin Neurophysiol 2000;111:1450] depend on the timing of stimulus occurrence. METHODS: Subjects had to discriminate the duration of tones. Occasionally, task-irrelevant frequency changes were used as distractors. In 3 experiments the stimulus onset asynchrony (SOA) was manipulated: In Experiment 1, SOAs of 1500, 2000 and 3000 ms were used in separate blocks; in Experiment 2, 5 different SOA of lengths between 1300 and 2500 ms were used within the blocks; in Experiment 3, a constant SOA of 1400 ms was compared with a SOA of random lengths between 1300 and 1500 ms. Performance data was analyzed for distraction effects. Event-related potentials (ERPs) were examined for deviance-related components, i.e. the mismatch negativity (MMN), the P3a and the re-orienting negativity (RON). RESULTS: Behavioral distraction effects were obtained in all experimental conditions. The electrophysiological data show MMN, P3a and RON for the deviating tones in all experimental conditions as well. CONCLUSIONS: The behavioral and electrophysiological deviance-related effects were not sensitive to the SOA manipulations. Therefore, the timing of the presentation can be adjusted to the proficiency level of the population to be tested without loosing the distraction effects.