Auditory brain response modified by temporal deviation of language rhythm: An auditory event-related potential study

The effects of the temporal disruption of language rhythm in Japanese on auditory evoked potentials were investigated in normal subjects. Auditory event-related evoked potentials (AERP) were recorded following syllables using a natural and deviated language rhythm by inserting various (0–400 ms) silent intervals between syllables. The language speed was changed to assess the effect of a deviant rhythm relative to the language speed on AERP in another experiment. The prolonging of intervals did not affect the N100-P150 components until the inserted interval became 400 ms, while the negative component (early negativity, EN), peaking at 250–300 ms, was enhanced when the interval was 100 ms or more. The N100-P150 components following deviated language rhythms did not change during the fast speed but did in the standard and slow speed. We considered that the N100-P150 components were changed by the mixed effects of adaptation and prediction related to the reading speed, and that EN was evoked by deviated language rhythm in a different way from that caused N100-P150 changes, possibly via mismatch detection process between deviant rhythm and intrinsic rehearsed rhythm.