Presence Of Transient Evoked Otoacoustic Emissions Research Articles

Oxidative Stress as a Risk Factor for Hearing Changes in HIV-positive Normal Listeners

OBJECTIVES:Human immunodeficiency virus-positive (HIV+) individuals can experience a decrease in antioxidants. Such deficiency can make inner ear cells and synapses more vulnerable to oxidative stress, resulting in auditory alterations, even in the presence of normal thresholds. This study aims to compare the audiological findings of HIV+ patients (with and without exposure to anti-retroviral treatment) to those of healthy individuals.METHODS:This was a cross-sectional observational study, comprising 42 normal-hearing adults divided into the Control Group (CG), without HIV; Group I (GI), HIV+, without exposure to the highly active anti-retroviral therapy (HAART); Group II (GII), HIV+, with exposure to HAART. All participants underwent conventional audiometry (0.25-8 kHz), high-frequency audiometry (9-20 kHz), transient evoked otoacoustic emissions (TEOAEs), efferent auditory pathway’s inhibitory effect assessment, brainstem auditory evoked potentials (BAEPs), and cognitive potential (P300).RESULTS:In the comparison of the hearing thresholds between the groups, there was a statistically significant difference for most of the frequencies assessed (GII presented hearing thresholds significantly poor when compared with other groups). The presence of TEOAE and the inhibitory effect was also verified in a significantly higher number of individuals in the CG than in the other groups. As for the BAEP, there was a statistically significant difference for the interpeak intervals I-V (GII showed higher values when compared with CG). For P300, there were no statistically significant differences.CONCLUSION:Normal-hearing HIV+ individuals (with and without exposure to HAART) presented with poor performance in the audiological procedures, suggesting the presence of auditory alterations even in the presence of normal-hearing thresholds.

Establishing auditory steady-state response thresholds to narrow band CE-chirps® in full-term neonates

Narrow band CE-chirps® were developed to provide a better synchronization of neural response due to the compensation of the traveling wave delay in the basilar membrane. These stimuli combined with a detection method that includes higher response harmonics on the auditory steady-state response (ASSR) recording was studied in this research. Objective(1) To establish air conduction thresholds for ASSR to narrow band CE-chirp® in normal hearing full-term neonates; (2) describe the test time needed for the above in one ear and (3) to compare the results in infants and normally hearing adults. MethodASSR to air-conducted stimuli were obtained in 30 full-term neonates (14 girls and 16 boys) with an average age of 34.3h of life. All neonates were presented presence of transient-evoked otoacoustic emissions (TEOAE) and result “pass” in automatic ABR at 35dB nHL before ASSR test. ASSR thresholds of both ears of 10 normal hearing adults (5 girls and 5 boys) varied in age between 23 and 30 years and with hearing thresholds better than or equal to 15dB HL at all frequencies between 250 and 8000Hz were recorded to compare with the neonate data. ResultsThe neonate ASSR thresholds estimated from 50% using cumulative distributions were 24.5, 13.5, 7.5 and 10dB nHL at 500, 1000, 2000, and 4000Hz, respectively. For the same frequency order, ASSR thresholds estimated from 90% of the neonates were 34.5, 28, 12.5 and 15dB nHL. It required 21.2 (±5)min on average to obtain threshold in each ear in neonates, with a range of 12–29min. When ASSR thresholds recorded in full-term neonates and adults were directly compared, the differences between these groups were not significant for 1000Hz (p=0.500), 2000Hz (p=0.610) and 4000Hz (p=0.362). However, at 500Hz, ASSR thresholds in neonates tend to be greater than in adults (p=0.001). ConclusionIn this study ASSR thresholds estimated from 90% of the neonates were 34.5, 28, 12.5 and 15dB nHL. It required 21.2 (±5)min on average to obtain threshold in each ear and ASSR thresholds to narrow band CE-chirp® in neonates are not significant for adults ASSR thresholds, except at 500Hz, when the ASSR thresholds in neonates tend to be greater than in adults.

Exploration fonctionnelle du nerf cochléaire et de l’audition

Since otoneurosurgical pathologies are being diagnosed increasingly early, the functional prognosis of surgery is gaining in importance. Hearing and cochlear nerve exploration can be carried out using three principal methods: pure-tone and speech audiometry, evoked otoacoustic emissions (EOAEs), and brainstem auditory evoked potentials (BAEPs). The aim of this paper is to present the current knowledge on auditory functional assessment. The medical and scientific literature from the Pubmed-Medline database was reviewed. Recently published related books were also included. RESULTS/DATA SYNTHESIS: Preoperative audiological evaluation makes it possible to assess pathology consequences on hearing. Depending on auditory status, conservative surgery, including intraoperative auditory monitoring, can be planned. From this perspective, prognostic factors for hearing preservation - such as the speech intelligibility score, the presence of transient EOAEs, and the presence of the BAEPs wave III - were identified. However, several surgical teams argue for a systematic conservative procedure, particularly when EOAEs are present, whatever the patient's preoperative hearing status. Postoperative audiological evaluation provides the opportunity for monitoring: in the short term, to detect complications early, through BAEPs recorded in the nonoperated ear; in the long term, to detect recurrence of the pathology. Moreover, the consequences of surgery on hearing can be assessed and long-term follow-up of auditory function can be carried out. Finally, the comparison of pre- and postoperative audiological status provides inductive feedback on surgery and electrophysiological monitoring, giving the otoneurosurgeon and neurophysiologist the opportunity to improve the entire procedure. Auditory functional assessment is essential for optimal care of tumor or functional pathologies involving the cochlear nerve and/or the cerebellopontine angle.

Transient evoked otoacoustic emissions in the elderly: Emisiones otoacústicas evocadas transitorias en el anciano

The purpose of this study was to analyse the changes in transient evoked otoacoustic emissions (TEOAEs) with age. We studied 232 subjects above 60 years of age with a battery of audio-logical tests, including TEOAEs. Our criterion for the presence of TEOAEs was based on a cutoff at overall wave reproducibility 55% or overall response level 4 dB SPL. The prevalence of TEOAEs in left ears was 55.6%. No TEOAEs were found in subjects with a pure-lone average (PTA) above 40 dB HL. In the subgroup with TEOAEs, a significant decrease in overall wave reproducibility with age was found. We compared 45 normal-hearing elderly subjects with TEOAEs with a control group of 20 normal-hearing young adults. The elderly had significantly lower mean overall response levels and mean overall wave reproducibility. Average hearing level was significantly higher in the elderly than in controls. We conclude that the prevalence of TEOAEs decreases with age, and that the overall response level and overall reproducibility decrease with age. This decrease may not be seen in isolation from the increase in hearing threshold level.El propósito de cste estudio fue analizar los cambios en las emisiones otoacústicas evocadas por transitorios (TEOAEs) con la edad. Estudiamos 232 sujetos con edades por encima de los 60 años, con una batería de prueba audiológicas que incluían las TEOAEs. Nuestro critcrio para la presencia de las TEOAEs se basó en un corte al 55% de reproducibilidad global de la onda, o a un nivel de respuesta global de 4 dB SPL. La prevalencia de las emisiones (TEOAEs) en oídos izquierdos fue de 55.6%. No se encontraron emisiones en sujetos con promedios tonales (PTA) por encima de 40dB HL. En el sub-grupo con TEOAEs, se encontró una disminución significativa en la reproductibilidad global de la onda relacionada con la edad. Comparamos 45 ancianos con audición normal y con TEOAEs, con un grupo control de 20 adullos jóvenes normooyentes. Los ancianos mostraron niveles globales de respuesta promedio y promedios de reproducibilidad global de la onda significativamente menores. El nivel auditivo promedio fue significativamente mayor en los ancianos que en los controles. Concluimos que la prevalencia de las TEOAEs disminuye con la edad y que el nivel global de respuesta y la reproducibilidad global disminuyen también con la edad. Esta disminución de debe observarse aisladamente en relación con el deterioro en los umbrales de audición.