Mismatch Negativity Occurrence with Verbal and Nonverbal Stimuli in Normal-Hearing Adults

THIEME 188 Original Research Mismatch Negativity Occurrence with Verbal and Nonverbal Stimuli in Normal-Hearing Adults Mirtes Brückmann1 Michele Vargas Garcia2 1 Graduate Program in Human Communication Disorders, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil 2 Department of Speech-Language Pathology and Audiology, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil Address for correspondence Mirtes Brückmann, Master, Av Roraima, 1000, prédio 26, Bairro Camobi, Santa Maria, CEP 97105-900, Brazil (e-mail: ). Int Arch Otorhinolaryngol 2020;24:e188–e196. Abstract Keywords ► auditory evoked potentials ► auditory cortex ► hearing ► adult ► electrophysiology Introduction The mismatch negativity (MMN) is a long-latency auditory evoked potential related to a passive elicited auditory event. Objective To verify the occurrence of MMN with different stimuli, to describe reference values in normal-hearing adults with verbal and nonverbal stimuli and to compare them with each other, besides analyzing the latency, area, and amplitude regarding gender and between the ears. Method Normal-hearing individuals, aged between 18 and 59 years old, participated in the study. As inclusion criterion in the study, all of them underwent tone threshold audiometry, logoaudiometry, tympanometry, and the Dichotic Sentence Identification (DSI) test, and later the MMN with 4 different stimuli, being 2 verbal (da/ta and ba/di) and 2 nonverbal stimuli (750/1,000Hz and 750/4,000Hz), which are considered stimuli with low and high contrast. Results A total of 90 individuals composed the sample, being 39 males and 51 females, with an average age of 26.9 years old. In the analysis of the latency, amplitude, and area of the four stimuli between the ears, they were not considered statistically different. There was a significant difference between all of the stimuli in terms of latency, amplitude and area, with the highest latency found in da/ta, and the greatest amplitude and area in ba/di. Regarding gender, there was only difference in the latency of the da/ta stimulus. Conclusion The da/ta and 750/1,000Hz stimuli elicited the most MMN in the population of normal-hearing adults. Among the genders, there was difference only regarding the latency of the verbal stimulus da/ta, and there was no difference between the ears. Introduction The mismatch negativity (MMN) is a long-latency auditory evoked potential related to a passive elicited auditory event, that is, without the need to perform any task or attention of the individual to the sound stimulus, as it arises in an automatic way, represented by a negative wave or a valley.1–3 received August 23, 2018 accepted July 27, 2019 published online January 28, 2020 DOI https://doi.org/ 10.1055/s-0039-1697990. ISSN 1809-9777. Mismatch negativity is generated when the individual automatically discriminates a sound change, in which the auditory system is based on memory traces of the regularity of a sound stimulus, and detects a change, regardless of his/her attention.1,4,5 This potential can be realized with several types of stimuli, among them the nonverbal sound stimulus (tone burst), in which the stimuli differ in frequency, intensity or Copyright © 2020 by Thieme Revinter Publicações Ltda, Rio de Janeiro, Brazil Mismatch Negativity Occurrence duration, or with verbal stimuli, using a syllabic set (consonant/vowel).5 Mismatch negativity is a useful exam to investigate neural mechanisms or to complement the audiological evaluation, thus it may also be valuable in the study of the auditory stimulus processing in the cortex3 and to be used for monitoring and prognosis in auditory rehabilitation processes. However, in Brazil, for example, this potential has always remained within the scope of research and, until today, it has not been mentioned as being used in the clinical routine, demonstrating the need for further studies on registry parameters and normative or reference data in the different age groups for their variables, which are latency, amplitude, and area. Therefore, it is justified to carry out the present study to obtain a comparative of MMN responses regarding latency, amplitude, and area, with different stimuli (verbal and nonverbal) in the adult population, in order to aggregate information that may contribute to the advancement in the use of this potential. In addition, it is justified to carry out the research on the SmartEP equipment (Intelligent Hearing Systems, Miami, FL, USA), which is used in many clinics and universities in Brazil, since few studies of this potential have been found in this equipment, being one with children and two with adults.6–8 Therefore, the objective of the present study is to verify the occurrence of MMN with different stimuli and to describe reference values in normal-hearing adults with verbal and nonverbal stimuli, and to compare them with each other, besides analyzing the latency, area, and amplitude regarding gender and between the ears. Method This was a cross-sectional, descriptive, quantitative study. It was sent to the Ethics and Research Committee on Human Subjects of the University in which the research was performed, being approved under the number CAAE 54827416.5.0000.5346. All of the individuals invited to participate in the study were advised of their free and spontaneous participation, and were informed about the procedures, risks, benefits, and confidentiality of the research. After the acceptance, all of them signed a free and informed consent form, which included all the procedures to be performed. The present study followed the principles of beneficence established by Resolution 466/12.9 The research procedures were performed individually at the audiology and electrophysiology outpatient clinic of a university hospital. Adult subjects of both genders, aged between 18 and 59 years old, were invited to participate in the present study. Those who met the following eligibility criteria participated in the sample: auditory thresholds up to 25 dBnHL in frequencies from 250 to 8000 Hz bilaterally; at least 8 years of schooling; values of normality in the Dichotic Sentence Identification (DSI) test in the integration stage;10 to not have external and middle ear alterations, identified by tympanometry; to not have a history of head trauma and/or stroke; to not present obvious neurological or psychiatric changes. Each individual was evaluated individually in a single day. First, the procedures for the analysis of the eligibility criteria Brückmann et al. were performed, including audiological anamnesis, meatoscopy, tone threshold audiometry, logoaudiometry, and tympanometry, to identify the normality of auditory thresholds. The DSI test was then performed, which was used as a screening for possible alterations in auditory processing, since it evaluates the figure-background ability for verbal sounds.10 For the DSI test, only the binaural integration stage was considered, and the (...truncated)