Infant Air and Bone Conduction Tone Burst Auditory Brain Stem Responses for Classification of Hearing Loss and the Relationship to Behavioral Thresholds

Auditory Electrophysiological Thresholds With Different Chirps and Their Correlation With Behavioral Thresholds in Hearing-Impaired Children

OBJECTIVES

Research focusing on changes in the clinical practice of audiological diagnosis has become increasingly necessary, particularly in pediatric audiology. The pursuit of accurate and reliable examinations has intensified given the importance of early detection and intervention in cases of childhood hearing loss. Thus, this study aims to investigate the correlation between electrophysiological auditory thresholds, as obtained through frequency-specific auditory brainstem responses with two distinct chirp stimuli (narrow-band CE-Chirp Level Specific and narrow-band iChirp), in children with hearing impairments. In addition, this research set out to correlate these thresholds with behavioral responses while simultaneously comparing the examination durations relative to the type of stimuli and the degree of hearing loss.

DESIGN

A cohort of 20 children (aged 6 months to 12 years) with varying degrees of hearing impairment (ranging from mild to profound) were recruited. The participants underwent bilateral measurement of their electrophysiological thresholds via auditory brainstem responses across different frequencies (500, 1000, 2000, and 4000 Hz), and the timeframe for determining these thresholds was carefully recorded. Subsequently, behavioral thresholds were ascertained using pure-tone audiometry or visual reinforcement audiometry based on the child's age. The data collected was subsequently analyzed using Pearson and Spearman correlation coefficients. To compare examination times, the Student t test and the Kruskal-Wallis test were used.

RESULTS

There was a pronounced correlation between the thresholds obtained through both narrow-band chirp stimuli. Moreover, a substantial correlation was found between electrophysiological and behavioral thresholds at 1000, 2000, and 4000 Hz, especially when compared with pure-tone audiometry. The mean differences between the electrophysiological and behavioral thresholds were below 6 dB nHL, and the exam duration was relatively consistent across both devices, averaging 47.63 (±19.41) min for the narrow-band CE-Chirp Level Specific and 52.42 (±26) min for the narrow-band iChirp. Notably, variations in exam duration did not relate to varying degrees of hearing loss when using the narrow-band CE-Chirp Level Specific. Nevertheless, the narrow-band iChirp indicated significantly shorter durations in instances of profound degree measurements, demonstrating a statistically significant difference.

CONCLUSIONS

The narrow-band CE-Chirp Level Specific and narrow-band iChirp stimuli provided similar estimates of electrophysiological auditory thresholds in children with hearing impairments, giving accurate estimations of behavioral thresholds. The time it took to complete the assessment is comparable between both stimuli. For the narrow-band iChirp, the degree of hearing loss was shown to impact the testing time, and children with profound hearing loss underwent faster exams. Ultimately, this study exhibits significant clinical implications as it reveals that the narrow-band CE-Chirp Level Specific and narrow-band iChirp stimuli could be remarkably promising for clinically exploring electrophysiological thresholds in children with hearing impairments.

Assessment of Interaural Attenuation in Infants and Young Children Using Bone-Conducted Auditory Brainstem Response

OBJECTIVES

In hearing assessment, the term interaural attenuation (IAA) is used to quantify the reduction in test signal intensity as it crosses from the side of the test ear to the nontest ear. In the auditory brainstem response (ABR) testing of infants and young children, the size of the IAA of bone-conducted (BC) stimuli is essential for the appropriate use of masking, which is needed for the accurate measurement of BC ABR thresholds. This study aimed to assess the IAA for BC ABR testing using 0.5 to 4 kHz narrowband (NB) CE-chirp LS stimuli in infants and toddlers with normal hearing from birth to three years of age and to examine the effects of age and frequency on IAA.

DESIGN

A total of 55 infants and toddlers with normal hearing participated in the study. They were categorized into three age groups: the young group (n = 31, infants from birth to 3 mo), middle-aged group (n = 13, infants aged 3-12 mo), and older group (n = 11, toddlers aged 12-36 mo). The participants underwent BC ABR threshold measurements for NB CE-chirp LS stimuli at 0.5 to 4 kHz. For each participant, one ear was randomly defined as the "test ear" and the other as the "nontest ear." BC ABR thresholds were measured under two conditions. In both conditions, traces were recorded from the channel ipsilateral to the test ear, whereas masking was delivered to the nontest ear. In condition A, the bone oscillator was placed on the mastoid of the test ear, whereas in condition B, the bone oscillator was placed on the mastoid contralateral to the test ear. The difference between the thresholds obtained under conditions A and B was calculated to assess IAA.

RESULTS

The means of IAA (and range) in the young age group for the frequencies 0.5, 1, 2, and 4 kHz were 5.38 (0-15) dB, 11.67 (0-30) dB, 21.15 (10-40) dB, and 23.53 (15-35) dB, respectively. Significant effects were observed for both age and frequency on BC IAA. BC IAA levels decreased with age from birth to 36 mo. In all age groups, smaller values were observed at lower frequencies and increased values were observed at higher frequencies.

CONCLUSIONS

BC IAA levels were both age and frequency dependent. The study found that the BC IAA values for lower stimulus frequencies were smaller than previously assumed, even in infants younger than 3 mo. These results suggest that masking should be applied in BC ABR threshold assessments for NB CE-chirp LS stimuli at 0.5, 1, and 2 kHz, even in young infants. Masking may not be necessary for testing at 4 kHz if a clear response is obtained at 15 dB normal-hearing level (nHL) in infants younger than 3 mo.

Audiogram Estimation by Auditory Brainstem Response with NB CE-Chirp LS stimulus in Normal Hearing Infants

Introduction  NB CE-Chirp LS was developed to improve the audiogram estimation by auditory brainstem response (ABR) thresholds during audiological assessment of infants and difficult to test children. However, before we know how the stimulus behaves in several types of hearing loss, it is important we know how the stimulus behaves in normal hearing infants. Objective  To describe ABR thresholds with NB CE-Chirp LS stimulus for 500, 1,000, 2,000, and 4,000 Hz, as well as the amplitude and absolute latency for ABR thresholds. Methods  Auditory brainstem response thresholds were evaluated with the Eclipse EP25 system. NB CE-Chirp LS was presented using an ER-3A insert earphone. EEG filter was 30 Hz high-pass and 1,500 Hz low-pass. The ABR threshold was defined as the lowest intensity capable of clearly evoke wave V, accompanied by an absent response 5 dB below. Results  Eighteen normal hearing infants were evaluated. The mean and standard deviation (SD) of the ABR threshold (dB nHL) were: 23.8 (±4.2); 14.4 (±5.7); 6.0 (±5.0); and 7.0 (±5.9). The mean and SD of the absolute latency (ms) were: 8.86 (±1.12); 9.21 (±0.95); 9.44 (±0.78); and 9.64 (±0.52). The mean amplitude (nV) and SD were: 0.123 (±0.035); 0.127 (±0.039); 0.141 (±0.052); and 0.105 (±0.028), respectively, for 500, 1,000, 2,000 and 4,000 Hz. Conclusion  Auditory brainstem response threshold with NB CE-Chirp LS reaches low levels, in special for high frequencies. It provides absolute latencies similar between frequencies with robust amplitude. The results obtained brings to the examiner more confidence in the results registered.

Association between hearing status and social participation in Japanese older adults: A cross-sectional study from the Japan gerontological evaluation study

PURPOSE

Hearing is known to decline with age. As sensitivity to speech declines, conversation becomes more difficult and social interactions are affected, resulting in increased risk of cognitive decline. This study aimed to examine the relationship between hearing status and social participation.

MATERIALS AND METHODS

The study included 21,117 adults aged 65 years or older who responded to a survey in 2019. The survey asked participants about their hearing status and how frequently they participated in certain social activities.

RESULTS

The analysis of the relationship between degree of hearing and social activity showed lower hearing status odds ratios for those who participated more frequently in social activities compared to those who participated less frequently. The odds ratios were as follows, hobby clubs (OR 0.81, 95%CI 0.78-0.84), activities such as teaching skills or passing on experiences to others (OR 0.69, 95%CI 0.65-0.75), and meeting with friends (OR 0.77, 95%CI 0.74-0.79). Compared to those who did not participate in social activities, those who participated in three or more types of groups had significantly lower hearing impairment (OR 0.75, 95% CI 0.72-0.79).

CONCLUSION

Hearing impairment was shown to inhibit participation in activities, including those that require communication with multiple people or smooth communication, those that involve a wide range of ages, and those that involve work and movement. Hearing impairment should be identified and addressed in its early stages to prevent its negative impact on social participation.

Audiological characteristics of children with congenital unilateral hearing loss: insights into Age of reliable behavioural audiogram acquisition and change of hearing loss

Objectives

The aims of this study were to report the audiological characteristics of children with congenital unilateral hearing loss (UHL), examine the age at which the first reliable behavioural audiograms can be obtained, and investigate hearing changes from diagnosis at birth to the first reliable behavioural audiogram.

Method

This study included a sample of 91 children who were diagnosed with UHL via newborn hearing screening and had reliable behavioural audiograms before 7 years of age. Information about diagnosis, audiological characteristics and etiology were extracted from clinical reports. Regression analysis was used to explore the potential reasons influencing the age at which first reliable behavioural audiograms were obtained. Correlation and ANOVA analyses were conducted to examine changes in hearing at octave frequencies between 0.5 and 4 kHz. The proportions of hearing loss change, as well as the clinical characteristics of children with and without progressive hearing loss, were described according to two adopted definitions: Definition 1: criterion (1): a decrease in 10 dB or greater at two or more adjacent frequencies between 0.5 and 4 kHz, or criterion (2): a decrease in 15 dB or greater at one octave frequency in the same frequency range. Definition 2: a change of ≥20 dB in the average of pure-tone thresholds at 0.5, 1, and 2 kHz.

Results

The study revealed that 48 children (52.7% of the sample of 91 children) had their first reliable behavioural audiogram by 3 years of age. The mean age at the first reliable behavioural audiogram was 3.0 years (SD 1.4; IQR: 1.8, 4.1). We found a significant association between children's behaviour and the presence or absence of ongoing middle ear issues in relation to the delay in obtaining a reliable behavioural audiogram. When comparing the hearing thresholds at diagnosis with the first reliable behavioural audiogram across different frequencies, it was observed that the majority of children experienced deterioration rather than improvement in the initial impaired ear at each frequency. Notably, there were more instances of hearing changes (either deterioration or improvement), in the 500 Hz and 1,000 Hz frequency ranges compared to the 2,000 Hz and 4,000 Hz ranges. Seventy-eight percent (n = 71) of children had hearing deterioration between the diagnosis and the first behavioural audiogram at one or more frequencies between 0.5 and 4 kHz, with a high proportion of them (52 out of the 71, 73.2%) developing severe to profound hearing loss. When using the averaged three frequency thresholds (i.e., definition 2), only 26.4% of children (n = 24) in the sample were identified as having hearing deterioration. Applying definition 2 therefore underestimates the proportion of children that experienced hearing changes. The study also reported diverse characteristics of children with or without hearing deterioration.

Conclusion

The finding that 78% of children diagnosed with UHL at birth had a decrease in hearing loss between the hearing levels at first diagnosis and their first behavioural audiogram highlights the importance of monitoring hearing threshold levels after diagnosis, so that appropriate intervention can be implemented in a timely manner. For clinical management, deterioration of 15 dB at one or more frequencies that does not recover warrants action.

The Complexity of Hearing Aid Fitting: Children with Congenital Hearing Loss and Middle Ear Dysfunction

BACKGROUND

The early diagnosis of hearing loss (HL) and hearing rehabilitation facilitate language and communication development. Some children exhibit mixed HL due to middle ear effusion (MEE) or acute otitis media (AOM). Mixed HL can affect HL evaluation and hearing aid (HA) fitting. The present study retrospectively evaluated the prevalence of MEE/AOM among children with congenital sensorineural HL (SNHL) who were fitted with HAs and its effect on the HA fitting.

METHODS

Thirty-six HA fittings carried out between 2017 and 2020 at one rehabilitation center were examined. Medical and audiological information was retrieved for children between 6 and 32 months old. The number of appointments and HA fitting times were recorded.

RESULTS

Twenty-eight children were included in the study. Eighteen children, in addition to SNHL, had a conductive component resulting from MEE/AOM. The children with these pathologies required significantly more HA fitting sessions and hearing tests, fewer real ear to coupler difference (RECD) measurements and longer HA fitting periods.

CONCLUSION

The findings indicate that a large number of children fitted with HAs have an additional conductive component that makes the fitting process longer. Since early rehabilitation is necessary for language development, otolaryngologists should be aware of the adverse effects of MEE/AOE on the HA fitting process. It is important to inform parents that when there is a conductive component, the HA fitting process may take longer and that treatment by an otolaryngologist is vital. This study stresses the importance of multidisciplinary cooperation for optimal HA fitting.

Predicting Behavioral Threshold at 6 and 8 kHz for Children and Adults Based on the Auditory Brainstem Response

PURPOSE

Common clinical application of auditory brainstem response (ABR) testing is limited to 0.25-4 kHz. Prior research has demonstrated associations between ABR and behavioral thresholds for tone burst stimuli > 4 kHz in adults, but there are no comparable data for children. The ability to predict behavioral thresholds > 4 kHz clinically based on the ABR would provide valuable audiologic information for individuals who are unable to provide behavioral thresholds. This study included children with hearing loss and children with normal hearing to determine the association between ABR and behavioral thresholds at 6 and 8 kHz.

METHOD

ABR and behavioral thresholds were obtained for children ages 4.7-16.7 years (M = 10.5, SD = 3.4) with sensorineural hearing loss (n = 24) or normal hearing sensitivity (n = 16) and for adults ages 18.4-54.4 years (M = 32.7, SD = 10.4) with sensorineural hearing loss (n = 13) or normal hearing sensitivity (n = 11). Thresholds obtained for 6 and 8 kHz using ABR and conventional audiometry were compared.

RESULTS

Differences between ABR and behavioral thresholds averaged 5-6 dB for both children and adults for both test frequencies, with differences of ≤ 20 dB in all instances. Linear mixed modeling for data from participants with hearing loss suggested that ABR threshold is a good predictor of behavioral threshold at 6 and 8 kHz for both children and adults. Test specificity was 100%; no participants with behavioral thresholds ≤ 20 dB HL had ABR thresholds > 25 dB nHL.

CONCLUSIONS

Initial evidence suggests that ABR testing at 6 and 8 kHz is reliable for estimating behavioral threshold in listeners with hearing loss and accurately identifies normal hearing sensitivity. The results of this study contribute to efforts to improve outcomes for vulnerable populations by reducing barriers to clinical implementation of ABR testing at > 4 kHz.

Normal reference values of low frequency specific air-conducted auditory brainstem responses among normal hearing children of different ages: A retrospective observational study

OBJECTIVES

To explore and compare the normal reference values (NRV) for low frequency specific air-conducted tone-burst auditory brainstem response (tb-ABR) among children of different ages and with normal hearing, because tb-ABR is often used to supplement the lack of click-evoked ABR (click-ABR) frequency but the NRV of this response threshold in different populations remain inconclusive.

METHODS

This retrospective observational study included children younger than 5 years of age with normal hearing in Hubei Province between November 2020 and September 2021. These children came to center of audiology for audiological examination including click-ABR due to different purposes and had accepted suggestion of tb-ABR test (0.5 kHz, 1 kHz). The children were divided into 5 groups according to age (0-12, 13-24, 25-36, 37-48, and 49-60 months of age), and 20 children (40 ears) met the inclusion criteria were selected from each group. The responding thresholds, peak latencies (PL), and inter-peak latencies (IPL) of the major waves were counted and compared in each group.

RESULTS

NRV of responding thresholds (dBnHL) in children aged 0-12, 13-24, 25-36, 37-48, and 49-60 months were 27.25 ± 9.47, 22.63 ± 5.31, 21.5 ± 5.33, 18.25 ± 5.83, and 21.63 ± 6.24 at 0.5 kHz, and 23.63 ± 7.16, 20.88 ± 7.06, 22 ± 4.21, 17.75 ± 6.09, and 21.38 ± 4.53 at 1 kHz, respectively. The response thresholds of children aged 0-12 months were significantly higher compared to children in other age groups at 0.5 kHz (all P < 0.05) and significantly higher than in children aged 37-48 months at 1 kHz (P < 0.05). There were significant differences among children of different ages in Wave III (P < 0.001) and Wave V (P < 0.001) in the peak latencies, and Waves I-III (P = 0.003) and Waves I-V (P < 0.001) in the inter-peak latencies at 0.5 kHz. Also, there were significant differences among children of different ages in Wave III and Wave V in the PL, and Waves I-III, Waves III-V, and Waves I-V in the IPL at 1 kHz (all P < 0.001).

CONCLUSION

The NRV of tb-ABR at 0.5 kHz and 1 kHz might differ among children of different ages. Newborn infants (<12 months old) might have a higher response threshold, while children aged 37-48 months might have a lower response threshold. However, it was a retrospective analysis with a small sample size, prospective contrast studies with larger samples are needed in the future.

Trajectory of hearing loss in children with unilateral hearing loss

Introduction

The aim of this study was to quantify the amount of deterioration in hearing and to document the trajectory of hearing loss in early identified children with unilateral hearing loss (UHL). We also examined whether clinical characteristics were associated with the likelihood of having progressive hearing loss.

Methods

As part of the Mild and Unilateral Hearing Loss Study, we followed a population-based cohort of 177 children diagnosed with UHL from 2003 to 2018. We applied linear mixed models to examine hearing trends over time including the average amount of change in hearing. Logistic regression models were used to examine the relationship between age and severity at diagnosis, etiology, and the likelihood of progressive loss and amount of deterioration in hearing.

Results

The median age of the children at diagnosis was 4.1 months (IQR 2.1, 53.9) and follow-up time was 58.9 months (35.6, 92.0). Average hearing loss in the impaired ear was 58.8 dB HL (SD 28.5). Over the 16-year period, 47.5% (84/177) of children showed deterioration in hearing in one or both ears from their initial diagnostic assessment to most recent assessment including 21 (11.9%) who developed bilateral hearing loss. Average deterioration in the impaired ear ranged from 27 to 31 dB with little variation across frequencies. Deterioration resulted in a change in category of severity for 67.5% (52/77) of the children. Analysis for children who were followed for at least 8 years showed that most lost a significant amount of hearing rapidly in the first 4 years, with the decrease stabilizing and showing a plateau in the last 4 years. Age and severity at diagnosis were not significantly associated with progressive/stable loss after adjusting for time since diagnosis. Etiologic factors (ENT external/middle ear anomalies, inner ear anomalies, syndromic hearing loss, hereditary/genetic) were found to be positively associated with stable hearing loss.

Conclusion

Almost half of children with UHL are at risk for deterioration in hearing in one or both ears. Most deterioration occurs within the first 4 years following diagnosis. Most children did not experience sudden "large" drops in hearing but more gradual decrease over time. These results suggest that careful monitoring of UHL especially in the early years is important to ensure optimal benefit from early hearing loss detection.

Auditory Brainstem Responses at 6 and 8 kHz in Infants With Normal Hearing

PURPOSE

Normative auditory brainstem response (ABR) data for infants and young children are available for 0.25-4 kHz, limiting clinical assessment to this range. As such, the high-frequency hearing sensitivity of infants and young children remains unknown until behavioral testing can be completed, often not until late preschool or early school ages. The purpose of this study was to obtain normative ABR data at 6 and 8 kHz in young infants.

METHOD

Participants were 173 full-term infants seen clinically for ABR testing at 0.4-6.7 months chronological age (M = 1.4 months, SD = 1.0), 97% of whom were ≤ 12 weeks chronological age. Stimuli included 6 and 8 kHz tone bursts presented at a rate of 27.7/s or 30.7/s using Blackman window gating with six cycles (6 kHz) or eight cycles (8 kHz) rise/fall time and no plateau. Presentation levels included 20, 40, and 60 dB nHL. The ABR threshold was estimated in 5- to 10-dB steps.

RESULTS

As previously observed with lower frequency stimuli, ABR waveforms obtained in response to 6 and 8 kHz tone bursts decreased in latency with increasing intensity and increasing age. Latency was shorter for 8-kHz tone bursts than 6-kHz tone bursts. Data tables are presented for clinical reference for infants ≤ 4 weeks, 4.1-8 weeks, and 8.1-12 weeks chronological age including median ABR latency for Waves I, III, and V and the upper and lower boundaries of the 90% prediction interval. Interpeak Latencies I-III, III-V, and I-V are also reported.

CONCLUSION

The results from this study demonstrate that ABR assessment at 6 and 8 kHz is feasible for young infants within a standard clinical appointment and provide reference data for clinical interpretation of ABR waveforms for frequencies above 4 kHz.

Correction of the Estimated Hearing Level of NB Chirp ABR in Normal Hearing Population

INTRODUCTION

The narrowband chirp (NB Chirp), a frequency-specific sound stimulus signal obtained by limiting the frequency bandwidth based on chirp, is applied to the frequency specified auditory brainstem response (fsABR) increasingly. Although some studies demonstrated that NB Chirp-evoked auditory brainstem response (NB Chirp ABR) causes a better neural response than tone burst-evoked auditory brainstem response and is preferred for fsABR, there is little known about how to better estimate an individual's hearing level through the threshold of NB Chirp ABR. The present study intended to compare the accuracy and deviation of NB Chirp ABR corrected by different approaches in estimating the hearing level of people with normal hearing.

METHODS

A total of 66 volunteers with normal hearing were randomly divided into a model group (n = 26), test group 1 (n = 20), and test group 2 (n = 20). The model group was used to calculate the threshold difference between NB Chirp ABR and pure-tone audiometry at 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz, as well as the regression equation, providing a reference for the correction of estimated hearing level of NB Chirp ABR. Test group 1 was used to observe the accuracy and deviation of the "noncorrection (N)," "threshold difference (A1)," and "regression equation (A2)" methods in correcting the estimated hearing level of NB Chirp ABR. Test group 2 was used to replicate the analysis of test group 1 to verify the repeatability of the experimental results. All data were analyzed using SPSS 24.0.

RESULTS

Test group 1 and test group 2 had similar results. First, the accuracy of the estimated hearing level of N was significantly higher than that of A1 or A2. Second, compared with "0," the deviation of the estimated hearing level of N was bigger than that of A1 or A2 at 500 Hz and 1,000 Hz, while similar at 2,000 Hz and 4,000 Hz. Finally, there was no significant difference in the deviation of the estimated hearing level between A1 and A2 at 500 Hz and 1,000 Hz.

CONCLUSION

Among people with normal hearing, it was necessary to correct NB Chirp ABR at 500 Hz and 1,000 Hz for lower deviation of the estimated hearing level. Both correction approaches based on threshold difference and regression equation can be used.

Effect of subject state on auditory brainstem response threshold using Kalman-weighted averaging

OBJECTIVES

This study aims to explore the impact of a subject's testing state on auditory brainstem response (ABR) thresholds using a novel ABR system (Vivosonic Integrity™), which incorporates Kalman-weighted averaging and bluetooth electrical isolation to address the limitation of conventional ABR limitation to obtain a stable result under non-sedated conditions, especially for infants and children.

METHOD

Twenty-four adults (18-34 years old, 48 ears) with normal hearing were enrolled for ABR testing under three different states (lying quietly in the supine position or sleeping-lying; watching silent videos quietly in a seated position-sitting; and writing in a seated position-writing), which simulate the behaviors of young children most often encountered during non-sedated Kalman-weighted ABR testing in clinical practice. The click ABR (cABR) and tone-burst ABR (tbABR) thresholds (0.5, 1, 2, and 4 kHz) of each subject and the time taken to reach the monaural threshold for each kind of stimulus were recorded.

RESULTS

(1) The cABR and tbABR thresholds were observed to increase in the following order: lying < sitting < writing. Significant threshold differences were found between any two states, except for between the sitting and lying states for the cABR and between sitting and writing for the 0.5 kHz tbABR. (2) The time required for cABR testing in the writing state was significantly longer than that in the lying and sitting states. The time required for 1 and 4 kHz tbABR testing in the lying state was significantly shorter than that in the sitting or writing state. For 2 KHz tbABR, only testing time under writing was significantly longer than that under lying. There were no significant differences in the time used for 0.5 kHz tbABR testing among different states.

CONCLUSIONS

Different testing states have significant impacts on the thresholds of ABRs using Kalman-weighted averaging. A subject's state during ABR testing warrants consideration, and normal levels and correction values to estimate the hearing threshold from the ABR threshold should be determined for different testing states.

Contribution of bone conduction click-evoked auditory brainstem responses to diagnosis of hearing loss in infants in France

INTRODUCTION

Neonatal hearing screening in France involves confirmation by a childhood hearing expert centre in case of suspected hearing loss. Although click-evoked air-conduction auditory brainstem responses (AC-ABR) are the gold standard in France, there are no guidelines for bone-conduction ABRs (BC-ABR). The present study assessed the interest of associating click-evoked BC- and AC-ABRs for diagnostic confirmation in neonatal hearing screening.

MATERIALS AND METHODS

A retrospective study included 59 infant ears with conductive hearing loss referred to the centre of Lyon, France. Objective hearing thresholds were compared between click-evoked BC- and AC-ABRs on a method previously validated in a normal-hearing population.

RESULTS

There was a significant difference in mean threshold between AC-ABR (53.27±1.189 dBnHL) and BC-ABR (28.1±0.935 dBnHL) (P<0.001). AC thresholds ranged from 40 to 60 dBnHL while BC thresholds exceeded 40 dBnHL in only 9 ears.

CONCLUSION

Using BC-ABRs could reduce the false-positive rate in neonatal bilateral permanent hearing loss screening, in complement to AC-ABRs using the same stimulus. Click-evoked BC-ABR could be contributive whenever conductive hearing loss is suspected, in complement to AC-ABR, without unreasonably increasing examination time.

Pediatric Ototoxicity: Current Trends and Management

Medical interventions to combat serious infection or malignancies carry significant morbidities, including ototoxicity. While these lifesaving drugs are often necessary to preserve life, the impact on quality of life for survivors is increasingly concerning for families and healthcare providers. Of primary importance for medical prescribers are appropriately sensitive ototoxicity grading scales and audiological monitoring protocols for surveillance for hearing loss. The intent of grading scales is to help communicate complicated audiological information to non-audiologist healthcare providers (such as oncologists) to help them make good decisions with regards to chemotherapy dosing. Appropriate audiological monitoring helps reduce the time delay between the adventitious onset of hearing loss and the diagnosis and intervention. Finally, pediatric ototoxicity grading and monitoring protocols help ensure timely access to adequate hearing habilitation, verification and validation of the management of permanent medication-induced hearing loss and tinnitus in children.

Optimizing Clinical Interpretation of Distortion Product Otoacoustic Emissions in Infants

OBJECTIVES

The purpose of this study was to analyze distortion product otoacoustic emission (DPOAE) level and signal to noise ratio in a group of infants from birth to 4 months of age to optimize prediction of hearing status. DPOAEs from infants with normal hearing (NH) and hearing loss (HL) were used to predict the presence of conductive HL (CHL), sensorineural HL (SNHL), and mixed HL (MHL). Wideband ambient absorbance was also measured and compared among the HL types.

DESIGN

This is a prospective, longitudinal study of 279 infants with verified NH and HL, including conductive, sensorineural, and mixed types that were enrolled from a well-baby nursery and two neonatal intensive care units in Cincinnati, Ohio. At approximately 1 month of age, DPOAEs (1-8 kHz), wideband absorbance (0.25-8 kHz), and air and bone conduction diagnostic tone burst auditory brainstem response (0.5-4 kHz) thresholds were measured. Hearing status was verified at approximately 9 months of age with visual reinforcement audiometry (0.5-4 kHz). Auditory brainstem response air conduction thresholds were used to assign infants to an NH or HL group, and the efficacy of DPOAE data to classify ears as NH or HL was analyzed using receiver operating characteristic (ROC) curves. Two summary statistics of the ROC curve were calculated: the area under the ROC curve and the point of symmetry on the curve at which the sensitivity and specificity were equal. DPOAE level and signal to noise ratio cutoff values were defined at each frequency as the symmetry point on their respective ROC curve, and DPOAE results were combined across frequency in a multifrequency analysis to predict the presence of HL.

RESULTS

Single-frequency test performance of DPOAEs was best at mid to high frequencies (3-8 kHz) with intermediate performance at 1.5 and 2 kHz and chance performance at 1 kHz. Infants with a conductive component to their HL (CHL and MHL combined) displayed significantly lower ambient absorbance values than the NH group. No differences in ambient absorbance were found between the NH and SNHL groups. Multifrequency analysis resulted in the best prediction of HL for the SNHL/MHL group with poorer sensitivity values when infants with CHL were included.

CONCLUSIONS

Clinical interpretation of DPOAEs in infants can be improved by using age-appropriate normative ranges and optimized cutoff values. DPOAE interpretation is most predictive at higher F2 test frequencies in young infants (2-8 kHz) due to poor test performance at 1 to 1.5 kHz. Multifrequency rules can be used to improve sensitivity while balancing specificity. Last, a sensitive middle ear measure such as wideband absorbance should be included in the test battery to assess possibility of a conductive component to the HL.

Measurements of bone conduction auditory brainstem response with the new audiometric bone conduction transducer Radioear B81<sup/>

OBJECTIVE

To compare recordings of bone conduction (BC) stimulated auditory brainstem response (ABR) obtained using the newer BC transducer Radioear B81 and the conventional BC transducer Radioear B71. Balanced electromagnetic separation transducer (BEST) design found in the B81 may influence the ABR magnitudes and latencies, as well as electrical artefacts.

DESIGN

ABRs to tone burst stimuli of 500 Hz, 2000 Hz, 4000 Hz, click stimulation, and broad-band chirp stimulation at 20 and 50 dB nHL were recorded. For each device, stimulus and intensity level, the ABR Jewett wave V amplitude and latency were obtained. The device-related electrical stimulus artefacts on the ABR recordings were also analysed by calculating the Hilbert envelope of the peri-stimulus recording segments.

STUDY SAMPLE

Twenty-three healthy adults with normal hearing were included in the study.

RESULTS

The ABRs obtained by the B81 were similar to that of the B71 in terms of ABR wave V amplitude and latency. However, the B81 produced smaller electrical artefacts than B71 and this difference was statistically significant.

CONCLUSIONS

The BC transducer Radioear B81 provides ABRs comparable to Radioear B71 while causing smaller artefacts.

Clinicians' Guide to Obtaining a Valid Auditory Brainstem Response to Determine Hearing Status: Signal, Noise, and Cross-Checks

PURPOSE

The auditory brainstem response (ABR) is a powerful tool for making clinical decisions about the presence, degree, and type of hearing loss in individuals in whom behavioral hearing thresholds cannot be obtained or are not reliable. Although the test is objective, interpretation of the results is subjective.

METHOD

This review provides information about evidence-based criteria, suggested by the 2013 Newborn Hearing Screening Program guidelines, and the use of cross-check methods for making valid interpretations about hearing status from ABR recordings.

RESULTS

The use of an appropriate display scale setting, templates of expected response properties, and objective criteria to estimate the residual noise, signal level, and signal-to-noise ratio will provide quality data for determining ABR thresholds. Cross-checks (e.g., immittance measures, otoacoustic emissions testing, functional indications of a child's hearing) are also needed to accurately interpret the ABR.

CONCLUSIONS

Using evidence-based ABR signal detection criteria and considering the results within the context of other physiologic tests and assessments of hearing function will improve the clinician's accuracy for detecting hearing loss and, when present, the degree of hearing loss. Diagnostic accuracy will ensure that appropriate remediation is initiated and that children or infants with normal hearing are not subjected to unnecessary intervention.

Update on Bone-Conduction Auditory Brainstem Responses: A Review

Auditory brainstem responses (ABR) have been used as a powerful and the most common objective tool to evaluate hearing sensitivity and to diagnose the types of hearing loss and neurological disorders, through the auditory peripheral pathway to a central level of the brainstem, since 1971. Although bone-conduction (BC) ABR could be an alternative to air-conduction (AC) ABR, as the former overcomes some limitations of the latter, the majority of clinicians rarely utilize it due to a lack of knowledge and no routine test administration. This review presents the weaknesses of AC ABR that apply to all clinical population, and discusses the development of BC ABR. The optimal placements of bone oscillators to obtain favorable clinical outcomes in infants, children, and adults, and the appropriate stimuli for BC ABR are examined. While providing absolute thresholds and latencies of BC ABR based on previous studies compared to AC ABR, this review includes clinical data of infants and young children with both normal hearing in terms of maturation, and with pathology such as congenital external auditory canal atresia. We recommend the future clinical application of BC ABR for candidacy as well as for patients with BC hearing implants.

[Intraoperative monitoring of cochlear nerve function during cerebello-pontine angle surgery]

BACKGROUND

Surgical procedures in the cerebello-pontine angle (CPA), e. g. for vestibular schwannoma, have an increased risk for damage to the cochlear nerve. Consequently, hearing deterioration up to complete deafness may result with severe impact on quality of life. Methods for intraoperative monitoring of function may minimize such risks.

OBJECTIVE

Review of current methods for intraoperative monitoring of the cochelar nerve and summary of new developments.

MATERIALS AND METHODS

Analysis and summary of literature, discussion of new methods.

RESULTS

Early auditory evoked potentials using click stimuli remain the standard method for intraoperative monitoring of cochlear nerve function. Amplitude and latency changes indicate a risk of postoperative hearing deterioration; however demonstrate only limited further differentiation of hearing quality. As novel methods, near-field recordings may allow faster feedback and auditory steady state responses potentially enable frequency specific testing.

CONCLUSIONS

Intraoperative monitoring of the cochlear nerve is an integral component of CPA surgery. It enables detection of potential nerve damage and thus contributes to avoiding postoperative functional deficits. Development and implementation of novel and additional approaches may further improve its clinical value.

Intra-operative hearing monitoring methods in middle ear surgeries

Hearing loss is a condition affecting millions of people worldwide. Conductive hearing loss (CHL) is mainly caused by middle ear diseases. The low frequency area is the pivotal part of speech frequencies and most frequently impaired in patients with CHL. Among various treatments of CHL, middle ear surgery is efficient to improve hearing. However, variable success rates and possible needs for prolonged revision surgery still frustrate both surgeons and patients. Nowadays, increasing numbers of researchers explore various methods to monitor the efficacy of ossicular reconstruction intraoperatively, including electrocochleography (ECochG), auditory brainstem response (ABR), auditory steady state response (ASSR), distortion product otoacoustic emissions (DPOAE), subjective whisper test, and optical coherence tomography (OCT). Here, we illustrate several methods used clinically by reviewing the literature.

Clinical Experience of Using Cortical Auditory Evoked Potentials in the Treatment of Infant Hearing Loss in Australia

This article presents the clinical protocol that is currently being used within Australian Hearing for infant hearing aid evaluation using cortical auditory evoked potentials (CAEPs). CAEP testing is performed in the free field at two stimulus levels (65 dB sound pressure level [SPL], followed by 55 or 75 dB SPL) using three brief frequency-distinct speech sounds /m/, /ɡ/, and /t/, within a standard audiological appointment of up to 90 minutes. CAEP results are used to check or guide modifications of hearing aid fittings or to confirm unaided hearing capability. A retrospective review of 83 client files evaluated whether clinical practice aligned with the clinical protocol. It showed that most children could be assessed as part of their initial fitting program when they were identified as a priority for CAEP testing. Aided CAEPs were most commonly assessed within 8 weeks of the fitting. A survey of 32 pediatric audiologists provided information about their perception of cortical testing at Australian Hearing. The results indicated that clinical CAEP testing influenced audiologists' approach to rehabilitation and was well received by parents and that they were satisfied with the technique. Three case studies were selected to illustrate how CAEP testing can be used in a clinical environment. Overall, CAEP testing has been effectively integrated into the infant fitting program.

Management of unilateral hearing loss

OBJECTIVE

A representative sample of literature regarding unilateral hearing loss (UHL) was reviewed to provide evidence of the effects of UHL and the intervention options available for children with UHL. Considerations during the assessment and management of children with UHL are illustrated using case illustrations.

METHOD

Research articles published from 2013 to 2015 were searched in the PubMed database using the keywords "unilateral hearing loss". Articles from 1950 to 2013 were included from a previous literature review on minimal hearing loss [1]. A retrospective review of charts of 14 children with UHL was also conducted.

RESULTS

The evidence indicates that children with UHL are more likely to have structural anomalies of the inner ear; may face challenges in six different domains, and have six intervention options available. Evidence also indicates that although some children appear to exhibit no delays or difficulties, others have significant challenges, some of which continue into adulthood.

CONCLUSIONS

Children with UHL have to be treated on a case-by-case basis. Parent education regarding UHL, its effects, and all available management options is critical so they can make informed decisions. Close monitoring and good communication between professionals in different domains is crucial in order to minimize the potential negative effects of UHL.

40-Hz Sinusoidal Auditory Steady-State Response and Tone Burst Auditory Brainstem Response Using a Kalman Filter to Determine Thresholds Pre- and Post-Myringotomy With Grommet Tube in Children With Mild, Low-Frequency Conductive Hearing Loss

PURPOSE

Accurate estimation of mild, low-frequency hearing loss is difficult in young children. This study aimed to determine the accuracy of 40-Hz sinusoidal auditory steady-state response (sASSR) compared with tone burst auditory brainstem response (TB-ABR) to detect mild, low-frequency hearing loss in children with otitis media with effusion and to measure postoperative thresholds.

METHODS

Thresholds at 500 and 4000 Hz were measured behaviorally and electrophysiologically using TB-ABR and 40-Hz sASSR with a Kalman filter in 26 children with otitis media with effusion. Recording was conducted preoperatively and postoperatively while children were actively awake. Repeated measures mixed analyses of variance were conducted to determine effects among measures and the two test frequencies.

RESULTS

Both 40-Hz sASSR and TB-ABR accurately detected preoperative and postoperative thresholds and were within 5-10 dB of the behavioral thresholds at 4000 Hz. At 500 Hz, the mean 40-Hz sASSR threshold was only 5 dB above the behavioral thresholds and 18 dB better than the 500-Hz ABR threshold. Positive correlations were found but not between 40-sASSR and TB-ABR at 500 Hz. Also, the interrater judgment of the response was better for sASSR (89%) than TB-ABR (83%).

CONCLUSION

The 40-Hz sASSR is more accurate than TB-ABR in determining a mild, low-frequency threshold.

The impact of degree of hearing loss on auditory brainstem response predictions of behavioral thresholds

OBJECTIVES

Diagnosis of hearing loss and prescription of amplification for infants and young children require accurate estimates of ear- and frequency-specific behavioral thresholds based on auditory brainstem response (ABR) measurements. Although the overall relationship between ABR and behavioral thresholds has been demonstrated, the agreement is imperfect, and the accuracy of predictions of behavioral threshold based on ABR may depend on degree of hearing loss. Behavioral thresholds are lower than ABR thresholds, at least in part due to differences in calibration interacting with the effects of temporal integration, which are manifest in behavioral measurements but not ABR measurements and depend on behavioral threshold. Listeners with sensory hearing loss exhibit reduced or absent temporal integration, which could impact the relationship between ABR and behavioral thresholds as degree of hearing loss increases. The present study evaluated the relationship between ABR and behavioral thresholds in infants and children over a range of hearing thresholds, and tested an approach for adjusting the correction factor based on degree of hearing loss as estimated by ABR measurements.

DESIGN

A retrospective review of clinical records was completed for 309 ears of 177 children with hearing thresholds ranging from normal to profound hearing loss and for whom both ABR and behavioral thresholds were available. Children were required to have the same middle ear status at both evaluations. The relationship between ABR and behavioral thresholds was examined. Factors that potentially could affect the relationship between ABR and behavioral thresholds were analyzed, including degree of hearing loss observed on the ABR, behavioral test method (visual reinforcement, conditioned play, or conventional audiometry), the length of time between ABR and behavioral assessments, and clinician-reported reliability of the behavioral assessment. Predictive accuracy of a correction factor based on the difference between ABR and behavioral thresholds as a function of ABR threshold was compared to the predictive accuracy achieved by two other correction approaches in current clinical use.

RESULTS

As expected, ABR threshold was a significant predictor of behavioral threshold. The agreement between ABR and behavioral thresholds varied as a function of degree of hearing loss. The test method, length of time between assessments, and reported reliability of the behavioral test results were not related to the differences between ABR and behavioral thresholds. A correction factor based on the linear relationship between the differences in ABR and behavioral thresholds as a function of ABR threshold resulted in more accurately predicted behavioral thresholds than other correction factors in clinical use.

CONCLUSIONS

ABR is a valid predictor of behavioral threshold in infants and children. A correction factor that accounts for the effect of degree of hearing loss on the differences between ABR and behavioral thresholds resulted in more accurate predictions of behavioral thresholds than methods that used a constant correction factor regardless of degree of hearing loss. These results are consistent with predictions based on previous research on temporal integration for listeners with hearing loss.

Comparison of 3 ABR Methods for Diagnosis of Retrocochlear Hearing Impairment

BACKGROUND The purpose of this study was to compare the effectiveness of methods for screening for retrocochlear pathologies based on auditory evoked brainstem responses (ABRs). The study compared the sensitivity, specificity, and effectiveness of these 3 techniques. MATERIAL AND METHODS The methods were: (i) standard ABR utilizing click-evoked responses, (ii) stacked ABR based on derived-band responses, and (iii) ABRs evoked by tone-pips (ABR TP). The methods were tested on patients with retrocochlear pathologies confirmed by MRI-Gd, normal-hearing subjects, and patients with cochlear hearing loss. The system and software used in the tests was NavPro AEP v.6.2.0 (BioLogic - Natus). Prior to testing, all subjects were given comprehensive audiologic and otologic examinations, including MR imaging. Sensitivity and specificity functions and predictive values of methods were determined. RESULTS The stacked ABR method as realized in the NavPro system exhibited high sensitivity but specificity was very low, due to the high variability of stacked ABR amplitudes. The standard ABR method had good specificity, but low sensitivity in cases of small tumors (below 1 cm in diameter). Best sensitivity and specificity was obtained with the ABR TP method. CONCLUSIONS The stacked ABR method allows small acoustic tumors to be detected, but produces high percentage of false positive results. The ABR TP method offers good sensitivity and specificity, and relatively high predictive value. The best option would be to use a two-stage screening, consisting of a standard ABR in the first stage and an ABR TP test in the second.

Air and Bone Conduction Click and Tone-Burst Auditory Brainstem Thresholds Using Kalman Adaptive Processing in Nonsedated Normal-Hearing Infants

OBJECTIVES

To study normative thresholds and latencies for click and tone-burst auditory brainstem response (TB-ABR) for air and bone conduction in normal infants and those discharged from neonatal intensive care units, who passed newborn hearing screening and follow-up distortion product otoacoustic emission. An evoked potential system (Vivosonic Integrity) that incorporates Bluetooth electrical isolation and Kalman-weighted adaptive processing to improve signal to noise ratios was employed for this study. Results were compared with other published data.

DESIGN

One hundred forty-five infants who passed two-stage hearing screening with transient-evoked otoacoustic emission or automated auditory brainstem response were assessed with clicks at 70 dB nHL and threshold TB-ABR. Tone bursts at frequencies between 500 and 4000 Hz were used for air and bone conduction auditory brainstem response testing using a specified staircase threshold search to establish threshold levels and wave V peak latencies.

RESULTS

Median air conduction hearing thresholds using TB-ABR ranged from 0 to 20 dB nHL, depending on stimulus frequency. Median bone conduction thresholds were 10 dB nHL across all frequencies, and median air-bone gaps were 0 dB across all frequencies. There was no significant threshold difference between left and right ears and no significant relationship between thresholds and hearing loss risk factors, ethnicity, or gender. Older age was related to decreased latency for air conduction. Compared with previous studies, mean air conduction thresholds were found at slightly lower (better) levels, while bone conduction levels were better at 2000 Hz and higher at 500 Hz. Latency values were longer at 500 Hz than previous studies using other instrumentation. Sleep state did not affect air or bone conduction thresholds.

CONCLUSIONS

This study demonstrated slightly better wave V thresholds for air conduction than previous infant studies. The differences found in the present study, while statistically significant, were within the test step size of 10 dB. This suggests that threshold responses obtained using the Kalman weighting software were within the range of other published studies using traditional signal averaging, given step-size limitations. Thresholds were not adversely affected by variable sleep states.

Potencial evocado auditivo de tronco encefálico por condução óssea: uma revisão integrativa

O objetivo deste estudo foi de realizar uma revisão de forma integrativa sobre os procedimentos utilizados nos critérios de aquisição do exame de Potenciais Evocados Auditivos de Tronco Encefálico por condução óssea com fins ao auxílio no diagnóstico de problemas auditivos. Foi realizada uma busca nas seguintes bases de dados: Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs), Medical Literature Analysis and Retrieval System Online (Medline) e Scientific Eletronic Library Online (SciELO). Utilizaram-se as seguintes palavras-chave: Potencial Evocado Auditivo, Eletrofisiologia e Condução Óssea, encontrados por meio de Descritores em Ciências da Saúde (DeCS). Os resultados apresentados são referentes aos 35 estudos selecionados. A maioria dos estudos optou pelo uso do estímulo clique, com transdutores por condução aérea os fones supra-aurais, como o TDH-39, para o estímulo por condução óssea, o vibrador Radioear B-71, com pressão de 425+/-25g. Observou-se que a mastoide foi à região onde mais se posicionou mais o vibrador ósseo. A maioria dos estudos refere usar polaridade alternada, com taxa de apresentação diversificada, sendo 57,7/s a mais utilizada e filtro de 30-3000 Hz, com uma janela de 15 ms de duração. Para taxa do estímulo a maioria dos estudos utilizou de 2048, e um total de estímulos de 2 registros. O Potencial Evocado Auditivo de Tronco Encefálico é um exame que vem sendo pesquisado há muitos anos e muito se tem descrito na literatura sobre seus aspectos de aquisição e analise, além de destacar a importância da sua utilização na população neonatal.

Longitudinal electrophysiological study of auditory pathway in small for gestational age infants

PURPOSE

To follow the maturation of the auditory pathway of infants born small for gestational age term, by studying absolute and interpeak latencies of Auditory Brainstem Response (ABR) in the first six months of life.

METHODS

Multicentric prospective longitudinal study. The ABR was carried out in the neonatal period in 96 newborn infants, 49 small for gestational age (SGA) and 47 appropriate for gestational age (AGA). Of these, 77 infants (39 SGA and 38 AGA) returned for a second evaluation. In the third evaluation, 70 infants (35 SGA and 35 AGA) returned.

RESULTS

SGA and AGA did not present significant differences in the neonatal period and at three months of life. However, at six months, there was statistical significant difference between SGA and AGA groups for the latencies of wave III and interpeak I-III. Latencies of ABR waves decreased more rapidly in the first three months than the third to the sixth month of life for the SGA. AGA group showed progressive decrease in latency of ABR waves during the six months.

CONCLUSION

The findings suggest that, for SGA infants, the maturational process of the auditory pathway occurs in different rate when compared to AGA infants. The SGA infants have faster maturation especially at the first three months of life, while in infants AGA, this process occurred in a constant and gradual way throughout the six months studied.

Potencial evocado auditivo de tronco encefálico por frequência específica por via aérea e via óssea em neonatos ouvintes normais

Objetivo determinar os níveis mínimos de resposta (NMR) e a latência da onda V do Potencial Evocado Auditivo de Tronco encefálico por Frequência específica (PEATE-FE) em neonatos ouvintes normais nas frequências de 0.5, 1, 2 e 4 kHz por via aérea e via óssea e determinar valores normativos. Métodos foram avaliados neonatos com audição normal, sendo realizado o PEATE-FE nas frequências de 0.5, 1, 2 e 4 kHz, tanto por via aérea (VA) quanto por via óssea (VO). Para cada frequência, foram avaliadas 12 orelhas em um total de 18 neonatos. A análise dos resultados avaliou o tempo de latência e a presença da onda V até a intensidade de 20 dBnNA para quatro intensidades e para os dois tipos de condução (aérea e óssea). Resultados observou-se aumento da latência da onda V com a diminuição da intensidade e maiores latências nas frequências mais baixas, tanto na VA quanto na VO. Porém, em fortes intensidades, em ambas condições, não houve diferença entre as latências de 0.5 e 1 kHz, contrariando os achados da literatura. Para VA, na frequência de 500 Hz, houve presença da onda V até 30 dBnNA em todas as orelhas, e em 1000 Hz, 11 orelhas (91,66 %) apresentaram resposta em 20 dBnNA; nas demais frequências, 100% das orelhas avaliadas apresentaram resposta em 20 dBnNA. Na VO, a presença da onda V em 20 dBnNA foi observada em todas as frequências estudadas. Conclusão os valores descritos podem ser considerados normativos e utilizados na clinica como padrão de normalidade, auxiliando no diagnóstico diferencial da perda auditiva ao nascimento.

Provisional stimulus level corrections for low frequency bone-conduction ABR in babies under three months corrected age

OBJECTIVE

To estimate bone-conduction stimulus level corrections by testing the auditory brainstem response (ABR) of normally-hearing newborns. The stimuli used were low frequency tone pips calibrated to reference levels derived from ISO 389 values.

DESIGN

Tone pips were presented via supra-aural earphones and a B71 Radioear bone vibrator at 0.5 or 1 kHz. ABR thresholds from both transducers were compared at each frequency.

STUDY SAMPLE

twenty-seven newborn hearing screening referrals (33 ears) who passed an ABR discharge criterion at 4 kHz.

RESULTS

Median air- and bone-conduction ABR threshold differences were 30 dB at 0.5 kHz and 20 dB at 1 kHz.

CONCLUSION

The 0.5 kHz data from this study and previous studies were compared. Previous studies suggested lower figures for the bone-conduction stimulus level correction. Likely sources of this discrepancy are discussed. The average 0.5 kHz bone-conduction correction value for infants < 3 months old is about 28 dB. The correction for 1 kHz is 20 dB. We recommend that calibration reference levels used in this study be adopted and that appropriate corrections be applied to bone conduction ABR thresholds in infants < 3 months old before calculation of any air-bone gap and subsequent clinical interpretation.

Correlação dos achados do PEATE-FE e da avaliação comportamental em crianças com deficiência auditiva

OBJETIVO: analisar e correlacionar os achados dos Potenciais Evocados Auditivos de Tronco Encefáico por Frequência Específica e da avaliação comportamental, por Via aérea e Via óssea, em crianças com perda auditiva sensorioneural ou mista. MÉTODO: a casuística foi composta por dez crianças com até três anos de idade, diagnosticadas com perda auditiva sensorioneural. Foram realizados os PEATE-FE nas frequências de 0.5, 1, 2 e 4 kHz e a audiometria comportamental nas mesmas frequências, tanto por via aérea como por via óssea. Os resultados dos dois procedimentos foram correlacionados afim de verificar se o PEATE-FE é capaz de predizer o status auditivo de crianças com deficiência auditiva. RESULTADOS: os resultados mostraram forte correlação entre os dois procedimento nas quatro frequências estudadas por via aérea; já na via óssea, foi encontrada forte correlação nas frequências de 0.5, 1 e 2 kHz e moderada em 4 kHz. CONCLUSÃO: os PEATE-FE estimaram a audição com forte precisão quando comparados à audiometria comportamental. Desta forma, a aplicação dos PEATE-FE possibilita a estimativa da audição até que possam ser determinados, com segurança, os limiares comportamentais na população estudada.

Predictive value of hearing assessment by the auditory brainstem response following universal newborn hearing screening

OBJECTIVE

This study set out to determine the accuracy with which tone pip ABR and click ABR, carried out in babies referred from universal newborn hearing screening, is able to predict the hearing outcome as determined by follow-up hearing tests.

STUDY SAMPLE

The cohort of babies studied were all babies referred for hearing assessment from the universal newborn hearing screen in Sheffield, UK for the period January 2002 to September 2007, who were found to have a significant hearing impairment.

DESIGN

The results of hearing assessment following referral from the newborn hearing screen were collected together with those of follow-up tests carried out up to an age when behavioural testing had established ear- and frequency-specific thresholds at 0.5, 1, 2 and 4 kHz.

RESULTS

The standard deviation of the difference between the follow up and the tone pip ABR thresholds was 10.5 dB for the 4-kHz tone pip, 16.8 dB for the 1-kHz tone pip, and ranged between 21.7 and 24.7 dB for click ABR.

CONCLUSIONS

The results of the study show that tone pip ABR following referral from newborn hearing screening has a similar accuracy to that reported in older subjects, and is a much better predictor compared to click ABR.

Prelingual sensorineural hearing loss and infants at risk: Western Sicily report

OBJECTIVE

To evaluate independent etiologic factor associated with sensorineural hearing loss (SNHL) in newborn at risk; to study the role of their interaction especially in NICU infants who present often multiple risk factors for SNHL.

METHODS

The main risk factors for SNHL reported by JCIH 2007 were evaluated on 508 infant at risk ranging from 4 to 20 weeks of life, transferred to the Audiology Department of Palermo from the main births centers of Western Sicily. After a global audiological assessment, performed with TEOAE, tympanometry and ABR, the prevalence and the effect of risk factors was statistically studied through univariate and multivariate analysis on the total population (normal and deaf subjects).

RESULTS

Fifty-one infants (10.03%) were diagnosed with SNHL (45 bilateral and 6 monolateral) with a mean hearing threshold of 87.39 ± 28.25 dB HL; from logistic regression analysis family history of hearing impairment (HI) and TORCH infections resulted independent significant risk factors (P<0.00001 and P=0.024 respectively). High SNHL percentages were evidenced also in NICU babies, due to the various pathologies and risk factors presented by these infants, and among newborns who suffered from hyperbilirubinemia requiring exchange transfusion (11.97% and 9.52% respectively). Craniofacial abnormalities (CFA) and syndromes associated to HI showed an important relationship (P<0.00001) with conductive hearing loss (CHL). Multiple regression analysis of the variation in SNHL among NICU infants evidenced an increased risk for SNHL of 21.24% and of 19.33% respectively in preterm infants and in case of hyperbilirubinemia if respiratory distress is concomitant with these risk factors. It was also observed an higher risk of SNHL (99.66%) in case of coexistence of prematurity and hyperbilirubinemia. Finally among infants with very low birth weight (VLBW) it was evidenced a statistically difference between the mean weight of SNHL infants respect to NHL newborns (P=0.048).

CONCLUSION

The high SNHL prevalence (10.03%) in our cohort underlines how infants at risk are more susceptible to suffer from SNHL; in particular NICU newborns have a 33% greater chance of developing SNHL, because of the presence of multiple risk factors (or=1.33) and their interaction. As the number of coexisting risk factors increases, the prevalence of SNHL also increases (r(2)=0.93).

Etiology and audiological outcomes at 3 years for 364 children in Australia

Hearing loss is an etiologically heterogeneous trait with differences in the age of onset, severity and site of lesion. It is caused by a combination of genetic and/or environmental factors. A longitudinal study to examine the efficacy of early intervention for improving child outcomes is ongoing in Australia. To determine the cause of hearing loss in these children we undertook molecular testing of perinatal “Guthrie” blood spots of children whose hearing loss was either detected via newborn hearing screening or detected later in infancy. We analyzed the GJB2 and SLC26A4 genes for the presence of mutations, screened for the mitochondrial DNA (mtDNA) A1555G mutation, and screened for congenital CMV infection in DNA isolated from dried newborn blood spots. Results were obtained from 364 children. We established etiology for 60% of children. One or two known GJB2 mutations were present in 82 children. Twenty-four children had one or two known SLC26A4 mutations. GJB2 or SLC26A4 changes with unknown consequences on hearing were found in 32 children. The A1555G mutation was found in one child, and CMV infection was detected in 28 children. Auditory neuropathy spectrum disorder was confirmed in 26 children whose DNA evaluations were negative. A secondary objective was to investigate the relationship between etiology and audiological outcomes over the first 3 years of life. Regression analysis was used to investigate the relationship between hearing levels and etiology. Data analysis does not support the existence of differential effects of etiology on degree of hearing loss or on progressiveness of hearing loss.

Auditory brainstem responses to bone-conducted brief tones in young children with conductive or sensorineural hearing loss

The bone-conduction (BC) tone ABR has been used clinically for over 20 years. The current study formally evaluated the test performance of the BC tone-evoked ABR in infants with hearing loss. Method. By comparing BC-ABR results to follow-up behavioural results, this study addressed two questions: (i) whether the BC tone ABR was successful in differentiating children with conductive versus sensorineural hearing loss (Study A; conductive: 68 ears; SNHL: 129 ears) and (ii) the relationship between BC ABR and behavioural hearing loss severity (Study B: 2000 Hz: 104 ears; 500 Hz: 47 ears). Results. Results demonstrate that the "normal" BC-ABR levels accurately differentiated normal versus elevated cochlear sensitivity (accuracy: 98% for 2000 Hz; 98% for 500 Hz). A subset of infants in Study A with elevated BC-ABR (i.e., no response at normal level) had additional testing at higher intensities, which allowed for categorization of the degree of cochlear impairment. Study B results indicate that the BC ABR accurately categorizes the degree of cochlear hearing loss for 2000 Hz (accuracy = 95.2%). A preliminary dBnHL-to-dBHL correction factor of "0 dB" was determined for 2000 Hz BC ABR. Conclusions. These findings further support the use of BC tone ABR for diagnostic ABR testing.

Audiologic profile of infants at risk: experience of a Western Sicily tertiary care centre

OBJECTIVE

To identify the incidence of sensorineural hearing loss (SNHL) on infant at risk and to classify the degree and type of hearing loss describing the main causes associated in Western Sicily. To compare single TEOAE and combined TEOAE/ABR techniques studying the referral rate, the false-positive and false-negative rates through concordance test (κ coefficient), sensitivity (TPR) and specificity (TNR) for each protocol.

METHODS

From January 2010 to June 2011, 412 infants at risk, ranging from 4 to 20 weeks of life, transferred to Audiology Department of Palermo from the births centers of Western Sicily, underwent to audiological assessment with TEOAE, tympanometry and ABR. The following risk factors were studied: family history of SNHL, consanguinity, low birth weight, prematurity, cranio-facial abnormality and syndromes associated to SNHL, respiratory distress, intensive care in excess of 5 days (NICU), pregnant maternal diseases, perinatal sepsis or meningitis, hyperbilirubinemia, ototoxic drugs administration.

RESULTS

Forty-seven infants (11.41%) were diagnosed with SNHL; median corrected age at final audiological diagnosis was 12 weeks. SNHL resulted moderate in 44.68%, severe in 10.64% and profound in 21 cases with a significant difference in family history and NICU infants (p<0.0001). As the number of coexisting risk factors increases, the percentage value of SNHL in infants (χ(2)=12.31, p=0.01, r(2)=0.98) and the degree of hearing loss (χ(2)=13.40, p=0.0095, r=0.92) also increase. The study of single TEOAE and combined TEOAE/ABR showed a statistical difference (χ(2)=14.89, p<0.001) with a low concordance value (κ=0.87) confirming the importance of combined techniques for NICU group (κ=0.86) where four cases (0.97%) of auditory neuropathy were diagnosed.

CONCLUSION

This study demonstrates the necessity to implement a neonatal hearing screening program in Western Sicily because of the high percentage of SNHL in infants at risk. Family history of HL is an independent significant risk factor for SNHL easily diagnosed through single TEOAE technique. Combined TEOAE/ABR is the gold standard for NICU babies which are at risk for auditory neuropathy. Coexisting risk factors are an additional risk factor for HL.

Response pattern based on the amplitude of ear canal recorded cochlear microphonic waveforms across acoustic frequencies in normal hearing subjects

Low-frequency otoacoustic emissions (OAEs) are often concealed by acoustic background noise such as those from a patient's breathing and from the environment during recording in clinics. When using electrocochleaography (ECochG or ECoG), such as cochlear microphonics (CMs), acoustic background noise do not contaminate the recordings. Our objective is to study the response pattern of CM waveforms (CMWs) to explore an alternative approach in assessing cochlear functions. In response to a 14-msec tone burst across several acoustic frequencies, CMWs were recorded at the ear canal from ten normal hearing subjects. A relatively long tone burst has a relatively narrow frequency band. The CMW amplitudes among different frequencies were compared. The CMW amplitudes among different frequencies were compared. Two features were observed in the response pattern of CMWs: the amplitude of CMWs decreased with an increase of stimulus frequency of the tone bursts; and such a decrease occurred at a faster rate at lower frequencies than at higher frequencies. Five factors as potential mechanisms for these features are proposed. Clinical applications such as hearing screening are discussed. Therefore, the response pattern of CMWs suggests that they may be used as an alternative to OAEs in the assessment of cochlear functions in the clinic, especially at low frequencies.

Multiple auditory steady state response thresholds to bone conduction stimuli in adults with normal and elevated thresholds

OBJECTIVE

Auditory steady state responses (ASSRs) to multiple air conduction (AC) stimuli modulated at ∼80 Hz have been shown to provide reasonable estimates of the behavioral audiogram. To distinguish the type of hearing loss (i.e., conductive, sensorineural, or mixed), bone conduction (BC) results are necessary. There are few BC-ASSR data, especially for individuals with hearing loss. The present studies aimed to (1) determine multiple ASSR thresholds to BC stimuli in adults with normal hearing, masker-simulated hearing loss, and sensorineural hearing loss (SNHL) and (2) determine how well BC-ASSR distinguishes normal versus elevated thresholds to BC stimuli in adults with normal hearing or SNHL.

DESIGN

Multiple ASSR and behavioral thresholds for BC stimuli were determined in two studies. Study A assessed 16 normal-hearing adults with relatively flat threshold elevations produced by 50, 60, and 70 dB SPL AC masking noise, as well as no masking. Study B assessed 10 adults with normal hearing and 40 adults with SNHL. In both studies, the multiple (500 to 4000 Hz) ASSR stimuli were modulated between 77 and 101 Hz and varied in intensity from 0 to 50 dB HL in 10-dB steps. Stimuli were presented using a B71 bone oscillator held on the temporal bone by an elastic band while participants relaxed or slept.

RESULTS

Study A: Correlations (r) between behavioral and ASSR thresholds for all conditions combined were 0.77, 0.87, 0.90, and 0.87 for 500, 1000, 2000, and 4000 Hz, respectively. ASSR minus behavioral threshold difference scores for all frequencies combined for the no-masker, 50, 60, and 70 dB SPL masker conditions were 14.3 ± 9.2, 12.1 ± 10.4, 12.7 ± 7.7, and 11.4 ± 8.1 dB, respectively. Study B: The difference scores for 500, 1000, 2000, and 4000 Hz were, on average, 15.7 ± 12.3, 10.3 ± 10.7, 9.7 ± 10.3, and 5.7 ± 7.9 dB, respectively, with correlations of 0.73, 0.84, 0.87, and 0.94 for the normal-hearing and SNHL groups combined. The ASSR minus behavioral difference scores were significantly larger for 500 Hz and significantly smaller for 4000 Hz compared with 1000 and 2000 Hz. Across all frequencies, the BC-ASSR correctly classified 89% of thresholds as "normal" or "elevated" (92% correct for 1000, 2000, and 4000 Hz).

CONCLUSIONS

The threshold difference scores and correlations in individuals with SNHL are similar to those in normal listeners with simulated SNHL. These difference scores are also similar to those shown by previous studies for the AC-ASSR in individuals with SNHL, at least for 1000 to 4000 Hz. The BC-ASSR provides a reasonably good estimate of BC behavioral threshold in adults, especially between 1000 and 4000 Hz. Further research is required in infants with hearing loss.

An initial overestimation of sensorineural hearing loss in NICU infants after failure on neonatal hearing screening

OBJECTIVE

Infants admitted to neonatal intensive care units have a higher incidence of significant congenital hearing loss. We classified audiologic diagnoses and follow-up in infants who had been admitted to our neonatal intensive care unit.

METHODS

We included all infants admitted to the neonatal intensive care unit at Sophia Children's Hospital between 2004 and 2009 who had been referred for auditory brainstem response measurement after failing neonatal hearing screening with automated auditory brainstem response. We retrospectively analyzed the results of auditory brainstem response measurement.

RESULTS

Between 2004 and 2009 3316 infants admitted to our neonatal intensive care unit had neonatal hearing screening. 103 infants failed neonatal hearing screening: 46 girls and 57 boys. After first auditory brainstem response measurement we found 18% had normal hearing or a minimal hearing loss. The remainder had a type of hearing loss, distributed as follows: 15% conductive, 32% symmetric sensorineural, 14% asymmetric sensorineural, and 21% absent auditory brainstem responses. Repeated auditory brainstem response measurement showed a shift in hearing outcome. The main difference was an improvement from symmetric sensorineural hearing loss to normal hearing. However, in a small percentage of children, the hearing deteriorated.

CONCLUSIONS

As many as 58% of infants in this high-risk population who failed the neonatal hearing screening were diagnosed with sensorineural hearing loss or absent auditory brainstem responses. An initial overestimation of sensorineural hearing loss of about 10% was seen at first auditory brainstem response measurement. This may be partially explained by a conductive component that has resolved. Finally, in a small percentage of children the hearing deteriorated.

Potenciais evocados auditivos por frequência específica em lactentes com audição normal

OBJETIVO: determinar os níveis mínimos de resposta (NMR) e a latência da onda V em lactentes ouvintes nas frequências de 0.5, 1, 2 e 4 kHz. MÉTODOS: foram avaliados 23 lactentes sem indicadores de risco para deficiência auditiva que apresentavam emissões otoacústicas evocadas por estímulo transiente (EOAET) e potenciais evocados auditivos de tronco encefálico automático (PEATE-A) presentes bilateralmente. RESULTADOS: obtiveram-se NMR médios de 34.2 dBnNA, 25.4 dBnNA, 19 dBnNA e 17.5 dBnNA para as frequências de 0.5, 1, 2 e 4 kHz, respectivamente. Os tempos médios de latência da onda V em 70 e 20 dBnNA, respectivamente, na frequência de 0.5 kHz foram de 10.75 ms e 15.2 ms, em 1 kHz de 8.9 ms e 13.4 ms; de 7.7 ms e 10.2 ms em 2 kHz, e para 4 kHz foram de 7.3 ms e 9.4 ms. CONCLUSÃO: os valores encontrados podem ser utilizados na prática clínica para orientar o diagnóstico diferencial da perda auditiva, complementando a avaliação auditiva de lactentes.