Alessandra Spada Durante

Características das emissões otoacústicas por transientes em programa de triagem auditiva neonatal

BACKGROUND Otoacoustic emissions (OAE) are considered the main instrument of the Newborn Hearing Screening Program (NHSP). AIM To analyze the OAE of newborns evaluated in the NHSP. METHOD Transient evoked OAE recordings were captured in 1000 infants. The data were analyzed using the analysis of multivaried variance (Manova). RESULTS Reference tables were calculated for the over all OAE levels and for frequency bands, according to gender and ear. The duration of the exam in the nursery was shorter than in the clinic. CONCLUSION The level of the OAE was influenced by gender and ear, except for 0,7kHz. However, there were no observed differences between neonates without and with auditory risk.

Maternal smoking during pregnancy: Impact on otoacoustic emissions in neonates

OBJECTIVES To determine the effect of maternal smoking during pregnancy on transient evoked otoacoustic emissions levels in neonates. METHODS This was a cross-sectional study investigating neonates in the maternity ward of a university hospital in the city of São Paulo, Brazil. A total of 418 term neonates without prenatal or perinatal complications were evaluated. The neonates were divided into two groups: a study group, which comprised 98 neonates born to mothers who had smoked during pregnancy; and a control group, which comprised 320 neonates born to mothers who had not. In order to compare the two ears and the two groups in terms of the mean overall response and the mean transient evoked otoacoustic emissions in response to acoustic stimuli delivered at different frequencies, we used analysis of variance with repeated measures. RESULTS The mean overall response and the mean frequency-specific response levels were lower in the neonates in the study group (p<0.001). The mean difference between the groups was 2.47 dB sound pressure level (95% confidence interval: 1.47-3.48). CONCLUSIONS Maternal smoking during pregnancy had a negative effect on cochlear function, as determined by otoacoustic emissions testing. Therefore, pregnant women should be warned of this additional hazard of smoking. It is important that smoking control be viewed as a public health priority and that strategies for treating tobacco dependence be devised.

Cortical Auditory Evoked Potential: evaluation of speech detection in adult hearing aid users

PURPOSE To analyze the presence of auditory cortical potential and its correlation with psychoacoustic detection of speech sounds as well as the latency of the P1, N1 e P2 components presented in free field in hearing impaired adults with and without amplification. METHODS We evaluated 22 adults with moderate to severe symmetrical bilateral sensorineural hearing loss, regular users of bilateral hearing aids. Speech sounds of low (/m/), medium (/g/) and high (/t/) frequencies were presented in sound field in decreasing intensities of 75, 65 and of 55 dBSPL in free field with and without hearing aids. The used equipment performs automatic statistical detection of the presence of response; forthermore, the latencies of waves P1, N1 e P2 were labeled and the psychoacoustic perception was registered. RESULTS The results demonstrated the increased presence of cortical response with hearing aids. We observed the correlation between psychoacoustic perception and automatic detection of 91% for the sounds /g/ and /t/ and ranged from 73 to 86% for the sound /m/. The averages of latencies P1-P2-N1 decreased with both increasing intensity and the use of hearing aids for the three sounds. The differences were significant for the sounds /g/ and /t/ in comparison with and without hearing aids. CONCLUSION There was increase in the presence of cortical auditory evoked potential with hearing aids. Automatic detection of cortical response provided with hearing aids showed 91% agreement with the psychoacoustic perception of the speech signal. In the analysis of latency measures of the P1, N1 and P2 components, it was observed a decrease with the increase of the signal intensity and the use of amplification for the three speech stimuli /m/, /g/ and /t/.

Assessment of hearing threshold in adults with hearing loss using an automated system of cortical auditory evoked potential detection.

INTRODUCTION The use of hearing aids by individuals with hearing loss brings a better quality of life. Access to and benefit from these devices may be compromised in patients who present difficulties or limitations in traditional behavioral audiological evaluation, such as newborns and small children, individuals with auditory neuropathy spectrum, autism, and intellectual deficits, and in adults and the elderly with dementia. These populations (or individuals) are unable to undergo a behavioral assessment, and generate a growing demand for objective methods to assess hearing. Cortical auditory evoked potentials have been used for decades to estimate hearing thresholds. Current technological advances have lead to the development of equipment that allows their clinical use, with features that enable greater accuracy, sensitivity, and specificity, and the possibility of automated detection, analysis, and recording of cortical responses. OBJECTIVE To determine and correlate behavioral auditory thresholds with cortical auditory thresholds obtained from an automated response analysis technique. METHODS The study included 52 adults, divided into two groups: 21 adults with moderate to severe hearing loss (study group); and 31 adults with normal hearing (control group). An automated system of detection, analysis, and recording of cortical responses (HEARLab®) was used to record the behavioral and cortical thresholds. The subjects remained awake in an acoustically treated environment. Altogether, 150 tone bursts at 500, 1000, 2000, and 4000Hz were presented through insert earphones in descending-ascending intensity. The lowest level at which the subject detected the sound stimulus was defined as the behavioral (hearing) threshold (BT). The lowest level at which a cortical response was observed was defined as the cortical electrophysiological threshold. These two responses were correlated using linear regression. RESULTS The cortical electrophysiological threshold was, on average, 7.8dB higher than the behavioral for the group with hearing loss and, on average, 14.5dB higher for the group without hearing loss for all studied frequencies. CONCLUSION The cortical electrophysiological thresholds obtained with the use of an automated response detection system were highly correlated with behavioral thresholds in the group of individuals with hearing loss.

Acoustic absorbance measurements in neonates exposed to smoking during pregnancy

OBJECTIVE To analyze acoustic absorbance using wideband tympanometry in neonates exposed to passive smoking during pregnancy. METHOD A study comprising 54 neonates in the control group (CG - unexposed) and 19 in the study group (SG - exposed) was carried out. Subjects were submitted to the wideband tympanometry test and subsequent analysis of absorbance of 17 frequencies. RESULT Low frequencies had a lower level of absorbance compared to high frequencies for both ambient and peak pressures, with no difference between the groups. CONCLUSION No effect of passive smoking on acoustic absorbance measurements in neonates was observed.

Efferent inhibition of otoacoustic emissions in preterm neonates

INTRODUCTION Abnormalities in auditory function of newborns may occur not only because of preterm birth, but also from the use of medications and from diseases related to prematurity. OBJECTIVE To analyze the inhibitory effect from stimulation of the olivocochlear efferent system on transient evoked otoacoustic emissions in preterm neonates, comparing these data with those from full-term neonates. METHODS This was a prospective, cross-sectional, contemporary cohort study with 125 neonates, pooled into two groups: full-term (72 full-term neonates, 36 females and 36 males, born at 37-41 weeks of gestational age); and preterm (53 neonates, 28 males and 25 females, born at ≤36 weeks of gestational age, evaluated at the corrected gestational age of 37-41 weeks). Otoacoustic emissions were recorded using linear and nonlinear click-evoked stimuli, with and without contralateral stimulation. RESULTS The inhibitory effect of the efferent pathway in otoacoustic emissions was different (p=0.012) between groups, and a mean reduction of 1.48dB SPL in full-term births and of 1.02dB SPL in preterm births was observed for the non-linear click-evoked stimulus. CONCLUSION The results suggest a reduced inhibitory effect of the olivocochlear efferent system on otoacoustic emissions in preterm neonates.

Wideband acoustic absorbance in children with Down syndrome

INTRODUCTION Tympanometry is currently the most frequently used tool for assessing the status of the middle ear, commonly assessed using a single 226Hz tone. However, the use of the Acoustic Immittance Measures with a wideband stimulus is a promising high-resolution evaluation, especially in individuals known to have middle ear alterations, such as Down syndrome patients. OBJECTIVE The aim of this study was to analyze the acoustic absorbance measurements in children with Down syndrome. METHODS Cross-sectional study, approved by the institutions ethics committee. Data were collected from 30 children, with a mean age of 8.4 years, 15 with Down syndrome (DS-study group) and 15 children with typical development and no hearing complaints (control group). Energy absorbance was measured at frequencies of 226-8000Hz at ambient pressure and at peak pressure as a function of frequency using TITAN equipment. Statistical analysis was performed using the established level of statistical significance of 5%. RESULTS With the 226Hz probe tone, 30 ears of the control group and 22 of the study group exhibited Type A tympanograms, whereas Type B was observed in eight children in the study group. The mean acoustic absorbance ratio of the study group was lower than that of the control group at frequencies centered at 2520Hz (p=0.008) for those with normal tympanometry results, and 226-4000Hz (p<0.03) for those with a Type B tympanometry curve. CONCLUSION The low energy absorption in the presence of normal tympanograms in children with Down syndrome may suggest middle ear abnormalities.

Automated cortical auditory evoked potentials threshold estimation in neonates

INTRODUCTION The evaluation of cortical auditory evoked potential has been the focus of scientific studies in infants. Some authors have reported that automated response detection is effective in exploring these potentials in infants, but few have reported their efficacy in the search for thresholds. OBJECTIVE To analyze the latency, amplitude and thresholds of cortical auditory evoked potential using an automatic response detection device in a neonatal population. METHODS This is a cross-sectional, observational study. Cortical auditory evoked potentials were recorded in response to pure-tone stimuli of the frequencies 500, 1000, 2000 and 4000Hz presented in an intensity range between 0 and 80dB HL using a single channel recording. P1 was performed in an exclusively automated fashion, using Hotellings T2 statistical test. The latency and amplitude were obtained manually by three examiners. The study comprised 39 neonates up to 28 days old of both sexes with presence of otoacoustic emissions and no risk factors for hearing loss. RESULTS With the protocol used, cortical auditory evoked potential responses were detected in all subjects at high intensity and thresholds. The mean thresholds were 24.8±10.4dB NA, 25±9.0dB NA, 28±7.8dB NA and 29.4±6.6dB HL for 500, 1000, 2000 and 4000Hz, respectively. CONCLUSION Reliable responses were obtained in the assessment of cortical auditory potentials in the neonates assessed with a device for automatic response detection.