The influence of speech stimuli contrast in cortical auditory evoked potentials

Studies about cortical auditory evoked potentials using the speech stimuli in normal hearing individuals are important for understanding how the complexity of the stimulus influences the characteristics of the cortical potential generated. OBJECTIVE: To characterize the cortical auditory evoked potential and the P(3) auditory cognitive potential with the vocalic and consonantal contrast stimuli in normally hearing individuals. METHOD: 31 individuals with no risk for hearing, neurologic and language alterations, in the age range between 7 and 30 years, participated in this study. The cortical auditory evoked potentials and the P(3) auditory cognitive one were recorded in the Fz and Cz active channels using consonantal (/ba/-/da/) and vocalic (/i/-/a/) speech contrasts. Design: A cross-sectional prospective cohort study. RESULTS: We found a statistically significant difference between the speech contrast used and the latencies of the N(2) (p = 0.00) and P(3) (p = 0.00) components, as well as between the active channel considered (Fz/Cz) and the P(3) latency and amplitude values. These correlations did not occur for the exogenous components N(1) and P(2). CONCLUSION: The speech stimulus contrast, vocalic or consonantal, must be taken into account in the analysis of the cortical auditory evoked potential, N(2) component, and auditory cognitive P(3) potential.