Potencial evocado auditivo Mismatch negativity em crianças com desenvolvimento típico

Abstract

Objective: To analyze the influence of the ear, gender and age variables in the mismatch negativity in children with typical development; and, to compare the different measures of this potential using verbal and nonverbal stimuli in the sample studied, thus providing reference values. Methods: Observational, descriptive, cross-sectional, quantitative study, comprising 23 children - 13 female and 10 male - whose age ranged from 5 years to 11 years and 11 months. They were divided into 2 groups: the first, with children aged 5 years to 7 years and 11 months; the second, with those aged 8 years to 11 years and 11 months. In order to compose the sample, the children were submitted to the following procedures: anamnesis, visual inspection of the external acoustic meatus, non-instrumental language assessment, pure-tone threshold audiometry, speech audiometry, central auditory processing tests, scale of auditory behavior, and brainstem auditory evoked potentials – neurological protocol. Lastly, they were assessed with the mismatch negativity, using the Smart Ep device from Intelligent Hearing Systems® (IHS). This potential was elicited through the oddball paradigm in the intensity of 60 dBnHL, using nonverbal stimuli (750 Hz frequent stimulus and 1000 Hz rare stimulus), and verbal stimuli ([da] frequent stimulus and [ta] rare stimulus), in binaural presentation mode via insert earphones. For the data analysis, the statistical Student’s t-test was used. Results: All of the children from the sample responded to this potential. There was no statistically significant difference for the ear, gender and age variables. In the comparison between the stimuli, statistically significant difference was noted for the latency, duration and area variables, showing higher values for the verbal stimulus. The reference values established for nonverbal stimuli were: latency of 249.8 ms, amplitude of -2.28 μv, duration of 82.97 ms, and area of 137.3 msXμv. As for the verbal stimuli, they were: latency of 265.3 ms, amplitude of -2.82 μv, duration of 110.5 ms, and area of 225.5 msXμv. Conclusion: There was no significant difference between the ear, gender and age variables in both stimuli researched. In the comparison between stimuli, higher values of latency, duration and area of the mismatch negativity were noted when the verbal stimuli were used. It was possible to propose reference values for children with typical development aged between 5 years and 11 years and 11 months.