Effect of ISAD use on speech stimulus decoding through speech-evoked ABR

Publication date: Available online 8 December 2016
Source:Brazilian Journal of Otorhinolaryngology
Author(s): Renata Aparecida Leite, Fernanda Cristina Leite Magliaro, Jeziela Cristina Raimundo, Mara Gândara, Sergio Garbi, Ricardo Ferreira Bento, Carla Gentile Matas
IntroductionThe electrophysiological responses obtained with the complex auditory brainstem response (cABR) provide objective measures of subcortical processing of speech and other complex stimuli. The cABR has also been used to verify the plasticity in the auditory pathway in the subcortical regions.ObjectiveTo compare the results of cABR obtained in children using Individual Sound Amplification Device (ISAD), before and after 9 months of adaptation, as well as to compare the results of these children with those obtained in children with normal hearing.MethodsFourteen children with normal hearing (Control Group – CG) and 18 children with mild to moderate bilateral sensorineural hearing loss (Study Group – SG), aged 7–12 years, were evaluated. The children were submitted to pure tone and vocal audiometry, acoustic immittance measurements and ABR with speech stimulus, being submitted to the evaluations at three different moments: initial evaluation (M0), 3 months after the initial evaluation (M3) and 9 months after the evaluation (M9); at M0, the children assessed in the study group did not use ISAD yet.ResultsWhen comparing the CG and the SG, it was observed that the SG had a lower median for the V–A amplitude at M0 and M3, lower median for the latency of the component V at M9 and a higher median for the latency of component O at M3 and M9. A reduction in the latency of component A at M9 was observed in the SG.ConclusionChildren with mild to moderate hearing loss showed speech stimulus processing impairment, and the main impairment is related to the decoding of the transient portion of this stimulus spectrum. It was demonstrated that the use of ISAD promoted neuronal plasticity of the Central Auditory Nervous System after an extended time of sensory stimulation.



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