Auditory Brainstem response electrophysiological thresholds with narrow band chirps stimuli in hearing infants.

OBJECTIVES: to describe reference values for the electrophysiological thresholds obtained in the frequency-specific Auditory Brainstem Response (fsABR) with the NB CE-Chirp® LS and NB iChirp stimuli in hearing infants and to compare the variables: Minimum Levels of Response (MLR), latency, amplitude and examination time. METHODS: the sample consisted of 74 full-term infants, with a mean age of 23.11 days, 29 females and 45 males. The participants underwent fsABR at the frequencies of 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz, to measure the MLR with the NB CE-Chirp® LS stimulus in the Eclipse equipment, and with the NB iChirp stimulus in the SmartEP, all in natural sleep and performed in the same session. The waveforms were evaluated by judges and later, for the comparison of thresholds and examination time, analyzed with the Wilcoxon test. To compare latency and amplitude, the Student's T Test and ANOVA were used for the same variables, but with the same stimulus. The Kruskal-Wallis test was used to compare the examination time at the different frequencies. RESULTS: The MLR and latency at 500 Hz and 1000 Hz showed a statistically significant difference between the stimuli, with lower thresholds and higher latencies for the NB iChirp. Higher amplitudes were obtained with the NB iChirp stimulus. The average examination time for the threshold investigation in the four frequencies was 40 min for each ear. CONCLUSION: it was possible to present reference values for the MLR and latencies for the NB CE-Chirp® LS and NB iChirp stimuli for hearing infants. In addition, with the NB iChirp, the latency of the responses was influenced by the frequency, but it was the stimulus that provided greater amplitudes. With the NB CE-Chirp® LS, the frequency did not influence latency, except at 500 Hz, and the stimulus provided recordings that facilitated the visualization of wave V. There was no difference in the examination time between the stimuli, nor between the test frequencies.

Auditory Brainstem Response with the iChirp stimuli in the infant's audiological diagnosis.

OBJECTIVE: to investigate the use of the iChirp stimulus in the infant's audiological diagnosis compared to stimuli typically used in the ABR in infants, in addition to suggesting reference values for the assessment of this population. METHODS: 62 infants participated in the study, 29 females and 33 males. The subjects underwent the recording of the Auditory Brainstem Response in the Smart Ep equipment, with the stimuli click, iChirp-broadband, tone burst and iChirp-narrowband, which were presented at three levels of intensity (20 dB, 40 dB and 60 dB) and, for tone burst and iChirp-narrowband stimuli, at different frequencies (0.5, 1 k, 2 k and 4 KHz). The data were later analyzed using Student's t-test. RESULTS: In general, the iChirp-broadband and iChirp-narrowband stimuli showed higher latency values and greater amplitudes when compared to click and tone burst stimuli. Furthermore, better signal-to-noise ratios were observed when contrasting iChirp-narrowband with tone burst. Additionally, reference values were established for the assessment of ABR in infants with the iChirp-broadband and iChirp-narrowband in the Smart-Ep equipment. CONCLUSION: The iChirp stimulus appears to be promising in the infant's audiological diagnosis, as its use promoted greater amplitudes and better wave morphology, which facilitates to mark the waveforms and provides greater efficiency in the investigation of the auditory thresholds. The indication of normative data also enables the clinical use of these stimuli in the infant's audiological diagnosis.

LS CE-Chirp® vs. Click in the neuroaudiological diagnosis by ABR / LS CE-Chirp® vs. Clique no diagnóstico neuroaudiológico pelo PEATE

Abstract Introduction: The chirp stimulus was developed seeking to counterbalance the delay of the sound wave on its journey through the cochlea, allowing the hair cells to depolarize at the same time. The result is a simultaneous stimulation providing better neural synchrony and, consequently, the recording of responses with greater amplitudes. Objective: To compare the absolute latency of waves I, III and V, the interpeak intervals I-III, III-V and I-V, amplitude values of wave V and its association with the amplitude of wave I, and the interaural difference V-V in the auditory brainstem response (ABR) using Click and LS CE-Chirp® stimuli to determine whether the responses evoked by LS CE-Chirp® could be applied to neuroaudiological diagnosis. Methods: Cross-sectional study with 30 normal-hearing individuals. The parameters used were: intensity of 85 dBnHL, alternating polarity; 17.1 stimuli/s and 100-3000 Hz filters. Results: The absolute latencies of waves I, III and V observed with LS CE-Chirp® and click did not show significant differences. Significantly higher amplitudes of wave V were observed with the LS CE-Chirp®. The interaural difference between the wave V latencies between stimuli showed no significant difference. Conclusion: The LS CE-Chirp® stimulus was shown to be as efficient as the click to capture ABR at high levels of stimulation, with the advantage of producing greater-amplitude V waves.

Resumo Introdução: O chirp foi desenvolvido para compensar o atraso da onda sonora em seu trajeto pela cóclea e possibilitar que as células ciliadas despolarizassem ao mesmo tempo. O resultado é uma estimulação simultânea que proporciona uma melhor sincronia neural e consequentemente o registro de respostas ocorre com maiores amplitudes. Objetivo: Comparar a latência absoluta das ondas I, III e V, os intervalos interpicos I-III, III-V e I-V, os valores de amplitude da onda V e sua relação com a amplitude da onda I e a diferença interaural V-V no Potencial Evocado Auditivo de Tronco Encefálico com o uso dos estímulos clique e LS CE-Chirp®, a fim de determinar se as respostas evocadas por LS CE-Chirp® poderiam ter aplicabilidade no diagnóstico neuroaudiológico. Método: Estudo transversal com 30 indivíduos normo-ouvintes. Os parâmetros usados foram: intensidade de 85 dBnNA, polaridade alternada; 17,1 estímulo/s e filtros de 100-3000 Hz. Resultado: As latências absolutas das ondas I, III e V observadas com LS CE-Chirp® e clique não tiveram diferenças significativas. Amplitudes significativamente maiores da onda V foram observadas com o LS CE-Chirp®. A diferença interaural entre as latências da onda V entre os estímulos não mostrou variação significativa. Conclusão: O estímulo LS CE-Chirp® mostrou ser tão eficiente quanto o clique na captação do potencial evocado auditivo de tronco encefálico, em níveis elevados de estimulação, com a vantagem de produzir ondas V de maior amplitude.

LS CE-Chirp® vs. Click in the neuroaudiological diagnosis by ABR.

INTRODUCTION: The chirp stimulus was developed seeking to counterbalance the delay of the sound wave on its journey through the cochlea, allowing the hair cells to depolarize at the same time. The result is a simultaneous stimulation providing better neural synchrony and, consequently, the recording of responses with greater amplitudes. OBJECTIVE: To compare the absolute latency of waves I, III and V, the interpeak intervals I-III, III-V and I-V, amplitude values of wave V and its association with the amplitude of wave I, and the interaural difference V-V in the auditory brainstem response (ABR) using Click and LS CE-Chirp® stimuli to determine whether the responses evoked by LS CE-Chirp® could be applied to neuroaudiological diagnosis. METHODS: Cross-sectional study with 30 normal-hearing individuals. The parameters used were: intensity of 85dBnHL, alternating polarity; 17.1 stimuli/s and 100-3000Hz filters. RESULTS: The absolute latencies of waves I, III and V observed with LS CE-Chirp® and click did not show significant differences. Significantly higher amplitudes of wave V were observed with the LS CE-Chirp®. The interaural difference between the wave V latencies between stimuli showed no significant difference. CONCLUSION: The LS CE-Chirp® stimulus was shown to be as efficient as the click to capture ABR at high levels of stimulation, with the advantage of producing greater-amplitude V waves.