There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude.

Reliable responses were obtained in the assessment of cortical auditory potentials in the neonates assessed with a device for automatic response detection.

Introduction The research in long latency auditory evokes potentials (LLAEP) in newborns is recent because of the cortical structure maturation, but studies note that these potentials may be evidenced at this age and could be considered as indicators of cognitive development. Purpose To research the exogenous potentials in term and premature infants during their first month of life. Materials and Methods The sample consisted of 25 newborns, 15 term and 10 premature infants. The infants with gestational age under 37 weeks were considered premature. To evaluate the cortical potentials, the infants remained in natural sleep. The LLAEPs were researched binaurally, through insertion earphones, with frequent /ba/ and rare /ga/ speech stimuli in the intensity of 80 dB HL (decibel hearing level). The frequent stimuli presented a total of 80% of the presentations, and the rare, 20%. The data were statistically analyzed. Results The average gestational age of the term infants was 38.9 weeks (± 1.3) and for the premature group, 33.9 weeks (± 1.6). It was possible to observe only the potentials P1 and N1 in both groups, but there was no statistically significant difference for the latencies of the components P1 and N1 (p > 0.05) between the groups. Conclusion It was possible to observe the exogenous components P1 and N1 of the cortical potentials in both term and preterm newborns of no more than 1 month of age. However, there was no difference between the groups.

Introduction  Mismatch Negativity (MMN) corresponds to a response of the central auditory nervous system. Objective  The objective of this study is to analyze MMN latencies and amplitudes in normal-hearing adults and compare the results between ears, gender and hand dominance. Methods  This is a cross-sectional study. Forty subjects participated, 20 women and 20 men, aged 18 to 29 years and having normal auditory thresholds. A frequency of 1000Hz (standard stimuli) and 2000Hz (deviant stimuli) was used to evoked the MMN. Results  Mean latencies in the right ear were 169.4ms and 175.3ms in the left ear, with mean amplitudes of 4.6µV in the right ear and 4.2µV in the left ear. There was no statistically significant difference between ears. The comparison of latencies between genders showed a statistically significant difference for the right ear, being higher in the men than in women. There was no significant statistical difference between ears for both right-handed and left-handed group. However, the results indicated that the latency of the right ear was significantly higher for the left handers than the right handers. We also found a significant result for the latency of the left ear, which was higher for the right handers. Conclusion  It was possible to obtain references of values for the MMN. There are no differences in the MMN latencies and amplitudes between the ears. Regarding gender, the male group presented higher latencies in relation to the female group in the right ear. Some results indicate that there is a significant statistical difference of the MMN between right- and left-handed individuals.

Objective To establish reference intervals for cognitive potential P300 latency using tone burst stimuli.Methods This study involved 28 participants aged between 18 and 59 years. P300 recordings were performed using a two-channel device (Masbe, Contronic). Electrode placement was as follows: Fpz (ground electrode), Cz (active electrode), M1 and M2 (reference electrodes). Intensity corresponded to 80 dB HL and frequent and rare stimulus frequencies to 1,000Hz and 2,000Hz, respectively. Stimuli were delivered binaurally.Results Mean age of participants was 35 years. Average P300 latency was 305ms.Conclusion Maximum acceptable P300 latency values of 362.5ms (305 + 2SD 28.75) were determined for adults aged 18 to 59 years using the protocol described.

Introduction  Preterm neonates are at risk of changes in their auditory system development, which explains the need for auditory monitoring of this population. The Auditory Steady-State Response (ASSR) is an objective method that allows obtaining the electrophysiological thresholds with greater applicability in neonatal and pediatric population. Objective  The purpose of this study is to compare the ASSR thresholds in preterm and term infants evaluated during two stages. Method  The study included 63 normal hearing neonates: 33 preterm and 30 term. They underwent assessment of ASSR in both ears simultaneously through insert phones in the frequencies of 500 to 4000Hz with the amplitude modulated from 77 to 103Hz. We presented the intensity at a decreasing level to detect the minimum level of responses. At 18 months, 26 of 33 preterm infants returned for the new assessment for ASSR and were compared with 30 full-term infants. We compared between groups according to gestational age. Results  Electrophysiological thresholds were higher in preterm than in full-term neonates ( p  < 0.05) at the first testing. There were no significant differences between ears and gender. At 18 months, there was no difference between groups ( p  > 0.05) in all the variables described. Conclusion  In the first evaluation preterm had higher thresholds in ASSR. There was no difference at 18 months of age, showing the auditory maturation of preterm infants throughout their development.

Purpose: To examine the maturation of the auditory pathway of children who were born at term and preterm, during 2 years and 6 months. Moreover, we tried to compare this maturation to the development of language skills of these children. Methods: It is a longitudinal and comparative study, which presents a clinical outcome related to the observation and analysis of auditory electrophysiological responses at the first month of life and 2 years and at 6 months old. The sample consisted of eight children, of both genders, being five born at term and three at preterm. Cortical Auditory Evoked Potential and the language evaluation were carried out through the Behavioral Observation Protocol. Results: Both term and premature babies passed through a period of maturation of the auditory pathway. In the correlation of gestation and maturation of the auditory pathway, we observed that the higher gestational age, the higher was the maturation of P1 wave. There was no correlation between language evaluation results and the maturation of the auditory pathway. Conclusion: Based on the results of this study, we concluded that there was maturation of the auditory pathway in the two-year period in both groups. A correlation between gestational age and maturation of P1 was observed, which shows that the higher is the gestational age, the greater is the maturity of this component. Regarding the language skills, no correlation with the maturation of this sample was noticed.Keywords: Hearing; Evoked potentials, Auditory; Infant, Premature; Child language; Gestational age RESUMO Objetivo: Analisar a maturação da via auditiva de crianças nascidas a termo e pré-termo, ao longo de dois anos e seis meses e comparar a maturação auditiva com o desenvolvimento das habilidades linguísticas dessas crianças. Métodos: O estudo teve como desfecho clínico a observação e análise das respostas eletrofisiológicas auditivas de crianças, durante o primeiro mês de vida e aos 2 anos e 6 meses de idade. A amostra constituiu-se de oito crianças, de ambos os gêneros, sendo cinco nascidas a termo e três nascidas pré-termo. Realizou-se o Potencial Evocado Auditivo Cortical e a avaliação de linguagem, por meio do Protocolo de Observação Comportamental. Resultados: Tanto os bebês nascidos a termo como os prematuros passaram por um período de maturação da via auditiva. Na correlação da idade gestacional e maturação da via auditiva, observou-se que, quanto maior a idade gestacional, maior a maturação da onda P1. Não houve correlação entre os resultados da avaliação de linguagem e a maturação da via auditiva. Conclusão: Houve maturação da via auditiva no período de dois anos e seis meses, em ambos os grupos estudados. Observou-se correlação entre Idade Gestacional e a maturação de P1, demonstrando que, quanto maior a Idade Gestacional, maior a maturação deste componente. Quanto às habilidades de linguagem, não houve correlação com a maturação da via auditiva.Descritores: Audição; Potenciais evocados auditivos; Prematuro; Linguagem infantil; Idade gestacio...

Introduction Long Latency Auditory Evoked Potentials (LLAEP) with speech sounds has been the subject of research, as these stimuli would be ideal to check individualś detection and discrimination. Objective The objective of this study is to compare and describe the values of latency and amplitude of cortical potentials for speech stimuli in adults with normal hearing. Methods The sample population included 30 normal hearing individuals aged between 18 and 32 years old with ontological disease and auditory processing. All participants underwent LLAEP search using pairs of speech stimuli (/ba/ x /ga/, /ba/ x /da/, and /ba/ x /di/. The authors studied the LLAEP using binaural stimuli at an intensity of 75dBNPS. In total, they used 300 stimuli were used (∼60 rare and 240 frequent) to obtain the LLAEP. Individuals received guidance to count the rare stimuli. The authors analyzed latencies of potential P1, N1, P2, N2, and P300, as well as the ampleness of P300. Results The mean age of the group was approximately 23 years. The averages of cortical potentials vary according to different speech stimuli. The N2 latency was greater for /ba/ x /di/ and P300 latency was greater for /ba/ x /ga/. Considering the overall average amplitude, it ranged from 5.35 and 7.35uV for different speech stimuli. Conclusion It was possible to obtain the values of latency and amplitude for different speech stimuli. Furthermore, the N2 component showed higher latency with the / ba / x / di / stimulus and P300 for /ba/ x / ga /.