Auditory Cortical Potential Obtained through Harmonic and Disharmonious Stimulus in Healthy Women

Introduction: Auditory cortical potentials indicate electrical changes in the peripheral and central auditory pathways as a function of acoustic stimulation. Clinical measures are used for evaluation of sound perception in the users of hearing aids or cochlear implants.

Objective: The study aims to evaluate the effect of harmonic and disharmonic stimulus in auditory cortical potentials components.

Methods: This is a cross-sectional study. We analyzed 60 records with harmonic and disharmonic stimuli in 15 healthy women without neurological and hearing sensitivity disorders. The tests were performed with the subject seated in an armchair, watching a video (without sound) without direct attention to the sound. It was performed harmonic stimulus (ACPhar) (severe harmonic set—250, 500, 1, 000 Hz—frequent stimulus and acute harmonic set—1,000, 2,000, 4,000 Hz infrequent stimulus) and disharmonic stimuli scans (ACPdishar) (severe harmonic set—250, 500, 1,000 Hz frequent stimulus and acute not harmonic set—1,000, 1,493, 3,135 Hz infrequent stimulus).They both spent 96 ms. Student t-test was applied to verify differences and the software Statistica 7.0 was used.

Results and Conclusion: We observed difference in the amplitude of P2 and N2, higher to ACPharm. Regarding P3a, the latency was shorter and of greater amplitude with disharmonious stimuli. These data suggest that ACPharm is related to physical stimulus discrimination and ACPdisharm reflects the automatic allocation of attention and alert due to unawareness of the infrequent stimulus disharmonic contrasts. However, further studies are encouraged to confirm this mechanism.

Keywords: electrophysiology, evoked potentials—auditory, acoustic stimulation.