Developmental changes in refractoriness of the cortical auditory evoked potential.

OBJECTIVE This study examined morphological changes in the cortical auditory evoked potential (CAEP) waveform as a function of varying stimulation rate. Stimuli were presented in a paradigm which indirectly assesses the refractory properties of the underlying neuronal generators. METHODS CAEPs were recorded in 50 normal-hearing children (3-12 years) and 10 young adults (24-26 years). A speech sound was presented in a stimulus train with sequentially decreasing inter-stimulus intervals (ISIs) of 2000, 1000, 560, and 360ms. Latencies and amplitudes of the P1, N1, and P2 components at the Cz electrode were examined as a function of stimulus rate and age. RESULTS Results revealed significant changes in the CAEP as a function of age and stimulation rate. At younger ages the N1-P2 component was elicited only at the slowest stimulation rates, and was more clearly apparent at successively faster stimulation rates as age increased. CONCLUSIONS We have described a stimulus paradigm that allows examination of the development of refractoriness by highlighting the interaction between age and rate on CAEP morphology. SIGNIFICANCE Complex maturational patterns of CAEP components are best understood when the effects of both age and stimulus rate on the CAEP waveform are considered.