Evaluation of residual hearing in cochlear implants candidates using auditory steady-state response

Conclusion: The correlations between behavioral and auditory steady-state response (ASSR) thresholds were significant at 500, 1000, 2000, and 4000 Hz. ASSR presented high sensitivity and specificity in the detection of residual hearing in cochlear implant candidates when compared with warble-tone audiometry. Objectives: To assess residual hearing in cochlear implant candidates by comparing the electrophysiological thresholds obtained in dichotic single-frequency ASSR with behavioral thresholds at 500, 1000, 2000, and 4000 Hz. Methods: This was a comparative study between ASSR and warble-tone audiometry thresholds in 40 cochlear implant candidates (80 ears) before cochlear implantation with bilateral severe-to-profound sensorineural hearing loss. Results: Thresholds were obtained in 62.5% of all frequencies evaluated in warble-tone audiometry and in 63.1% in the ASSR. ASSR sensitivity was 96% and specificity was 91.6%. Mean differences between behavioral and ASSR thresholds did not reach significance at any frequencies. Strong correlations between behavioral and ASSR thresholds were observed in 500, 1000, and 2000 Hz and moderate in 4000 Hz, with correlation coefficients varying from 0.65 to 0.81. On 90% of occasions, ASSR thresholds were acquired within 10 dB of behavioral thresholds.     

Comparing auditory steady-state responses amplitude evoked by simultaneous air- and bone-conducted stimulation in newborns

Objective: The aim of this study was to evaluate the potential interactions of the simultaneous presentation of air- and bone-conducted stimuli on auditory steady-state responses (ASSR) amplitude in newborns. Design: Bone- and air-conducted stimuli were sinusoidal carrier tones of 500 and 2000?Hz respectively modulated in amplitude (95% depth). Air- and bone- conducted stimuli were either simultaneously recorded in the same ear using insert earphones and bone vibrator respectively, or recorded individually (single stimulation). Study sample: Sixty-nine well babies (135 ears) with ages ranging from 1 to 16 days (mean of 9.2?±?7.9 days) were tested in this study. Results: No significant changes in ASSR amplitude by air-conducted stimuli were observed when evoked by simultaneous or single stimulation. The same trend prevailed for ASSR amplitudes evoked by bone-conducted stimuli. Conclusions: The results of this study suggest that the simultaneous stimulation of air-and bone-conducted stimuli does not alter ASSR amplitude values in well babies. Therefore, the results support the use of this technique as a potential hearing screening tool to discriminate between conductive and sensorineural hearing loss.     

Auditory steady-state response thresholds of adults with sensorineural hearing impairments: Umbrales de las respuestas auditivas de estado estable en adultos con hipoacusia sensorineural

This study evaluated the use of multiple auditory steady-state responses (ASSRs) to estimate the degree and configuration of behavioral audiograms of subjects with sensorineural hearing impairments. Place specificity of the multiple-ASSR method was also assessed. Multiple amplitudemodulated (77–105 Hz) tones (500, 1000, 2000 and 4000 Hz) were simultaneously presented to one ear. The results showed that, on average, multiple-ASSR thresholds were 14±13, 8±9, 10±10 and 3±10 dB above behavioral thresholds for 500, 1000, 2000 and 4000 Hz, respectively. Behavioral and multiple-ASSR thresholds were significantly correlated (r =0.75–0.89). There were no significant differences between behavioral and multiple-ASSR measures of the audiogram configuration. In subjects with steep-sloping ≥30 dB/octave) hearing losses, multiple-ASSR thresholds did not underestimate behavioral thresholds, revealing good place specificity. These results indicate that the multiple-ASSR method provides good estimates of the degree and configuration of hearing in individuals with sensorineural hearing impairments.

Este estudio evaluó el uso de las repuestas auditivas de estado estable (ASSR) para estimar el grado y la configuración de la audiometria conductual en sujetos con hipoacusia sensorineural. También se evaluó la especificidad tonal del método de ASSR múltiple. Se presentaron tonos múltiples de amplitud modulada (77–105 Hz) en 500, 1000, 2000 y 4000 Hz en forma simultánea para cada oído. Los resultados muestran que en promedio, los umbrales de ASSR-múltiple son 14±13, 8±9, 10±10 y 3±10 dB por encima del umbral conductual para las frecuencias 500, 1000, 2000 y 4000Hz respectivamente. No hubo una diferencia significativa (r = 0.75–0.89) entre los umbrales conductuales y los umbrales por ASSR-múltiple en la configuración del audiograma. En sujetos con curvas de perfil descendente abrupto (≥30 dB/octave), los umbrales obtenidos por ASSR-múltiple no subestimaron los umbrales conductuales y demostraron buena relación de especificidad frecuencial. Estos resultados indican que el método ASSR-múltiple proporciona un buen estimado del grado y la configuración de la audición de los individuos con hipoacusia sensorineural.     

Assessment of low-frequency hearing with narrow-band chirp-evoked 40-Hz sinusoidal auditory steady-state response

Objective To determine the clinical utility of narrow-band chirp-evoked 40-Hz sinusoidal auditory steady state responses (s-ASSR) in the assessment of low-frequency hearing in noisy participants. Design Tone bursts and narrow-band chirps were used to respectively evoke auditory brainstem responses (tb-ABR) and 40-Hz s-ASSR thresholds with the Kalman-weighted filtering technique and were compared to behavioral thresholds at 500, 2000, and 4000?Hz. A repeated measure ANOVA and post-hoc t-tests, and simple regression analyses were performed for each of the three stimulus frequencies. Study sample Thirty young adults aged 18–25 with normal hearing participated in this study. Results When 4000 equivalent response averages were used, the range of mean s-ASSR thresholds from 500, 2000, and 4000?Hz were 17–22?dB lower (better) than when 2000 averages were used. The range of mean tb-ABR thresholds were lower by 11–15?dB for 2000 and 4000?Hz when twice as many equivalent response averages were used, while mean tb-ABR thresholds for 500?Hz were indistinguishable regardless of additional response averaging. Conclusion Narrow-band chirp-evoked 40-Hz s-ASSR requires a ～15?dB smaller correction factor than tb-ABR for estimating low-frequency auditory threshold in noisy participants when adequate response averaging is used.     

A comparison of 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) thresholds in awake adult subjects

Evoked potential thresholds using the 40?Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) were recorded at 500?Hz and 4000?Hz test frequencies in 36 subjects with normal acuity, and 30 subjects with sensorineural hearing loss. ASSR threshold sensation levels (SLs) were lower in ears with greater degrees of hearing loss, and for the 500?Hz stimulus. Mean SLs (maximum duration of a single recording: 89 seconds) were as follows at 500?Hz and 4000?Hz respectively: normal hearing group, 16.9±10.3?dB and 42.4±14.4?dB; mild-moderate group, 10.6±8.8?dB and 23.8±8.1?dB; severe-profound group, 10.0±13.2?dB and 21.5±18.9?dB. CAEP SLs showed no change with hearing level and CAEP/behavioural differences were similar at each test frequency. Mean SLs for CAEP threshold (single recording duration: 84 seconds) at 500?Hz and 4000?Hz respectively were: normal hearing group, 10.3±6.4?dB and 11.5±3.8?dB; mild-moderate group, 8.4±7.4?dB and 13.2±12.4?dB; severe-profound group, 11.0±6.6?dB and 15.9±16.4?dB. The results of this study suggest that while both 40?Hz ASSR and CAEP can reflect the behavioural audiogram, CAEPs may provide a more reliable estimate of hearing in awake adults.     

Multiple auditory steady-state response thresholds to bone-conduction stimuli in young infants with normal hearing

OBJECTIVE: Multiple auditory steady-state responses (ASSRs) probably will be incorporated into the diagnostic test battery for estimating hearing thresholds in young infants in the near future. Limiting this, however, is the fact that there are no published bone-conduction ASSR threshold data for infants with normal or impaired hearing. The objective of this study was to investigate bone-conduction ASSR thresholds in infants from a Neonatal Intensive Care Unit (NICU) and in young infants with normal hearing and to compare these with adult ASSR thresholds. DESIGN: ASSR thresholds to multiple bone-conduction stimuli (carrier frequencies: 500 to 4000 Hz; 77 to 101-Hz modulation rates; amplitude/frequency modulated; single-polarity stimulus) were obtained in two infant groups [N = 29 preterm (32 to 43 wk PCA), tested in NICU; N = 14 postterm (0 to 8 mo), tested in sound booth]. All infants had passed a hearing screening test. ASSR thresholds, amplitudes, and phase delays for preterm and postterm infants were compared with previously collected adult data. RESULTS: Mean (+/-1 SD) ASSR thresholds were 16 (11), 16 (10), 37 (10), and 33 (13) dB HL for the preterm infants and 14 (13), 2 (7), 26 (6), and 22 (8) dB HL for the postterm infants at 500, 1000, 2000, and 4000 Hz, respectively. Both infant groups had significantly better thresholds for 500 and 1000 Hz compared with 2000 and 4000 Hz, in contrast to adults who have similar thresholds across frequency (22, 26, 18, and 18 dB HL). When 500- and 1000-Hz thresholds were pooled, pre- and postterm infants had better low-frequency thresholds than adults. When 2000- and 4000-Hz thresholds were pooled, pre- and postterm infants had poorer thresholds than adults. ASSR amplitudes were significantly larger for low frequencies compared with high frequencies for both infant groups, in contrast to adults, who show little difference across frequency. ASSR phase delays were later for lower frequencies compared with higher frequencies for infants and adults, except for 500 Hz in the preterm group. ASSR phase delays were later for infants compared with adults across frequency. CONCLUSIONS: Infant bone-conduction ASSR thresholds are very different from those of adults. Overall, these results indicate that low-frequency bone-conduction thresholds worsen and high-frequency bone-conduction thresholds improve with maturation. Bone-conduction ASSR threshold differences between the postterm infants and adults probably are due to skull maturation. Differences between preterm and older infants may be explained both by skull changes and a masking effect of high ambient noise levels in the NICU (and possibly to other issues due to prematurity).     

A comparison of 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) thresholds in awake adult subjects

Evoked potential thresholds using the 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) were recorded at 500 Hz and 4000 Hz test frequencies in 36 subjects with normal acuity, and 30 subjects with sensorineural hearing loss. ASSR threshold sensation levels (SLs) were lower in ears with greater degrees of hearing loss, and for the 500 Hz stimulus. Mean SLs (maximum duration of a single recording: 89 seconds) were as follows at 500 Hz and 4000 Hz respectively: normal hearing group, 16.9+/-10.3 dB and 42.4+/-14.4 dB; mild-moderate group, 10.6+/-8.8 dB and 23.8+/-8.1 dB; severe-profound group, 10.0+/-13.2 dB and 21.5+/-18.9 dB. CAEP SLs showed no change with hearing level and CAEP/behavioural differences were similar at each test frequency. Mean SLs for CAEP threshold (single recording duration: 84 seconds) at 500 Hz and 4000 Hz respectively were: normal hearing group, 10.3+/-6.4 dB and 11.5+/-3.8 dB; mild-moderate group, 8.4+/-7.4 dB and 13.2+/-12.4 dB; severe-profound group, 11.0+/-6.6 dB and 15.9+/-16.4 dB. The results of this study suggest that while both 40 Hz ASSR and CAEP can reflect the behavioural audiogram, CAEPs may provide a more reliable estimate of hearing in awake adults.     

Comparison of auditory steady-state responses and auditory brainstem responses in audiometric assessment of adults with sensorineural hearing loss

Objective

Many of the medico-legal patients who claimed compensation may exaggerate hearing loss that varies in degree, nature, and laterality. The purpose of this study was to investigate whether Auditory Steady-State Response (ASSR) could be used to predict the hearing level of adults, and whether ASSR could become a better testing method than Auditory brainstem response (ABR) in audiometric assessment of adults with sensorineural hearing loss.

Methods

This was a prospective study, which was conducted in a tertiary referral hospital. From January to June 2007, 142 subjects (284 ears) with varying degrees of sensori-neural hearing impairment were included in this study. Four commonly used frequencies (500, 1000, 2000, 4000 Hz) were evaluated. All subjects received pure-tone audiometry, multi-channel ASSR, and ABR tests for threshold measurement. The correlation of pure tone thresholds with ASSR and ABR thresholds were assessed.

Results

Between multi-channel ASSR and pure tone thresholds, a difference of less than 15 dB was found in 71% while a difference of less than 25 dB was found in 89% of patients. The correlation coefficient (r) of multi-channel ASSR and pure tone thresholds were 0.89, 0.95, 0.96, and 0.97 at 500, 1000, 2000, and 4000 Hz, respectively. The strength of the relationship increased with increasing frequency. On the other hand, between ABR and pure-tone thresholds, a difference of less than 15 dB was found in 31%; a difference of less than 25 dB was found in 62% of patients. The r correlation value for ABR and pure tone thresholds was 0.83.

Conclusion

ASSR is a more reliable test for the accurate prediction of auditory thresholds than ABR. It can be a powerful and convenient electro-physiologic examination tool for clinically assessing of adults with sensorineural hearing loss.     

An investigation into the clinical utility of ipsilateral/ contralateral asymmetries in bone-conduction auditory steady-state responses

Abstract

Objective: To determine whether ipsilateral/contralateral asymmetries in the bone-conduction (BC) ASSR are robust enough in infants to be used clinically to isolate the test ear. Design: Retrospective investigation of three two-channel BC ASSR datasets. Subjects: Forty-eight adults (mean age 26.7 years), 49 infants (mean age 29.6 weeks). Methods: BC ASSR stimuli were presented as amplitude/frequency modulated sinusoidal tones with carrier frequencies of 500, 1000, 2000, and 4000 Hz (?10 to 45 dB HL). Results: Infants showed greater differences in ipsilateral/contralateral mean amplitudes and phase delays for all experimental conditions compared to adults. Ninety percent of infants had ipsilateral/contralateral asymmetries at 500 and 4000 Hz (20–35 dB HL) using an “amplitude or phase delay” criterion, and at 4000 Hz (20–25 dB HL) using an “amplitude and phase delay” criterion. Conclusions: As ipsilateral/contralateral asymmetries are not consistently present for 1000- and 2000-Hz BC ASSRs in infants, clinical masking would be needed at these frequencies to isolate the test ear. For 500- and 4000-Hz BC ASSRs, the accuracy of using these asymmetries requires clinical confirmation in a group of infants with hearing loss.     

Comparison of multiple auditory steady-state responses (80 versus 40 Hz) and slow cortical potentials for threshold estimation in hearing-impaired adults

This study evaluated the use of multiple auditory steady-state responses (ASSRs) and slow cortical potentials (SCPs) to estimate behavioural audiograms in adults for compensation cases. Two groups of 23 subjects were assessed using either 80 Hz or 40 Hz multiple simultaneous tones with carrier frequencies of 0.5, 1.0, 2.0, and 4.0 kHz. SCP thresholds for 0.5, 1.0, and 2.0 kHz were obtained for both groups. Mean evoked potential thresholds (dB HL) minus behavioural pure-tone thresholds (dB HL) difference scores were 5–17 dB for the 80 Hz group, 1–14 dB for the 40 Hz group, and 20–22 dB for the SCPs. Thresholds for 40 Hz ASSR were significantly closer to behavioural thresholds than were 80 Hz or SCP thresholds. SCP and 40 Hz ASSR audiogram estimates were obtained more quickly than the 80 Hz ASSR. Multiple 40 Hz ASSR is the method of choice for evoked potential threshold estimation in adults.

Sumario

Este estudio evaluó el uso de las respuestas auditivas múltiples de estado estable (ASSR) y de los potenciales corticales lentos (SCP) para estimar en casos de compensación, los audiogramas comportamentales de adultos. Se realizaron pruebas en dos grupos de 23 sujetos utilizando tonos múltiples simultáneos a 80 ó 40 Hz con frecuencias portadoras de 500, 1000, 2000 y 4000 Hz. Se obtuvieron umbrales SCP para 500, 1000 y 2000 Hz en ambos grupos. Los umbrales promedio de potenciales evocados (dBHL) menos las respuestas tonales comportamentales se ubicaron entre 5 y 17dB para el grupo de 80 Hz, de 1 a 40 dB para el grupo de 40 Hz y de 20 a 22 dB para los SCP. Los umbrales de las ASSR de 40 Hz estuvieron significativamente mas cercanos a los umbrales comportamentales que los de 80 Hz o los umbrales SCP. Los SCP y las ASSR-40 Hz se obtuvieron más rápido que las ASSR-80 Hz. Las ASSR múltiples de 40 Hz son el método de elección para la estimación de umbrales con potenciales evocados en adultos.     

Multiple auditory steady-state responses to bone-conduction stimuli in adults with normal hearing

ASSR thresholds to bone-conduction stimuli were determined in 10 adults with normal hearing using mastoid placement of the bone oscillator. ASSRs to 0-50 dB HL bone-conduction stimuli and to 30-60 dB HL air-conduction stimuli were compared. The effect of alternating stimulus polarity on air- and bone-conduction ASSRs was also investigated. Stimuli were bone- and air-conduction amplitude-modulated tones (500-4000 Hz carrier frequencies, modulated at 77-101 Hz). ASSRs were recorded using the Rotman MASTER research system. Mean (1SD) bone-conduction ASSR thresholds were 22(11), 26(13), 18(8), and 18(11) dB HL for 500, 1000, 2000, and 4000 Hz, respectively. Except for a steeper slope at 500 Hz, ASSR intensity-amplitude functions for binaural bone- and air-conduction stimuli showed the same slopes; intensity-phase-delay functions were steeper at 1000 Hz for ASSRs to bone-conduction stimuli. ASSR amplitudes and phases did not differ for single- versus alternated-stimulus polarities for both bone- and air-conduction stimuli. The steeper amplitude slope for ASSRs to 500 Hz stimuli may reflect a nonauditory contribution to the ASSR.     

Auditory steady-state response and auditory brainstem response thresholds in children

The inclusion of the auditory steady-state response (ASSR) into test-batteries for objective audiometry has allowed for clinical comparisons with the most widely used procedure, the auditory brainstem response (ABR). The current study describes ASSR and ABR thresholds for a group of infants and young children with various types and degrees of hearing loss. A sample of 48 subjects (23 female) with a mean age of 2.8 ± 1.9 years SD were assessed with a comprehensive test-battery and classified according to type and degree of hearing loss. Thresholds were determined with a broadband click-evoked ABR and single frequency ASSR evoked with continuous tones (0.25–4 kHz) amplitude modulated (67–95 Hz). Mean difference scores (±SD) between the ABR and high frequency ASSR thresholds were 9.8 (±11), 3.6 (±12) and 10.5 (±12) dB at 1, 2 and 4 kHz, respectively. An ASSR mean threshold for 2–4 and 1–4 kHz compared to the ABR threshold revealed an average difference of 7 (±9) and 7.9 (±8) dB, respectively. The overall correlation between the ABR and ASSR thresholds was highest for the mean ASSR thresholds of 2–4 and 1–4 kHz (r = 0.92 for both conditions). Correlations between the ABR and individual ASSR frequencies were slightly less (0.82–0.86). The average of the 2–4 kHz ASSR thresholds correlated best with the click-evoked ABR for all categories of hearing loss except for the sensorineural hearing loss category for which the 1–4 kHz ASSR average was better correlated to ABR thresholds. Findings demonstrate the reliability of verifying high frequency ASSR thresholds with a click-evoked ABR as an important cross-check in infants for whom behavioural audiometry may not be possible.     

Estimating audiometric thresholds using simultaneous acquisition of ASSR and ABR from QASSR in patients with sensorineural hearing loss

Objectives: To evaluate the accuracy with which the innovative QASSR method predicts behavioral thresholds in adult patients with sensorineural hearing loss. Design: Subjects were tested at four carrier frequencies (500, 1000, 2000, and 4000?Hz).The resulting QASSR recordings were analyzed for thresholds and magnitude/phase characteristics. Tone-burst ABR was recovered from QASSR signal using CLAD method and analyzed in the time domain. The electrophysiological estimates were compared to hearing thresholds determined behaviorally. Study sample: Sixteen ears of nine volunteer subjects recruited from a clinical population. Results: All mean threshold estimates differed less than 3?dB for QASSR and less than 5?dB for ABR at 1000, 2000 and 4000Hz (carrier or pure-tone test frequencies). The largest differences were observed for both at 500?Hz (5.63 and 11.56?dB respectively).The audiometric configurations of QASSR and ABR estimates followed those of the respective behaviorally determined configurations across ears tested. Conclusions: QASSR method merges two dissimilar stimulation techniques, transient and steady-state, to create a hybrid stimulation-and-analysis paradigm that seems to improve the overall performance of the electrophysiological threshold estimation. The unique feature of the QASSR technique is the additional information afforded by the transient ABR, recovered from the same recording. The QASSR thus holds promise to be a very useful tool for practical clinical applications.     

The relationship between hearing loss and vestibular dysfunction in patients with sudden sensorineural hearing loss

Objective: To investigate the relationship between hearing loss and vestibular dysfunction in patients with sudden sensorineural hearing loss (SSHL).

Methods: Clinical data including the symptom of vertigo of 149 SSHL patients were investigated retrospectively. Pure tone audiometry, ocular vestibular-evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP) evoked by air-conducted sound (ACS), and caloric test were employed for cochlear and vestibular function assessment. The relationship between hearing level and vestibular dysfunction was analyzed.

Results: The pure tone averages (PTAs) (mean?±?SD) of SSHL patients with and without vertigo were 88.81?±?21.74 dB HL and 72.49?±?21.88 dB HL (Z?=??4.411, p?=?0.000), respectively. The PTAs of SSHL patients with abnormal and normal caloric test were 84.71?±?22.54 dB HL and 70.41?±?24.07 dB HL (t?=??2.665, p?=?0.009), respectively. Conversely, vertigo and abnormal caloric results also happened more frequently in patients with profound hearing loss. However, no consistent tendency could be found among vestibular evoked myogenic potentials (VEMPs) responses or hearing loss.

Conclusions: SSHL patients with vertigo or abnormal caloric test displayed worse hearing loss; and vice versa, vertigo and abnormal caloric results happened more frequently in SSHL patients with profound hearing loss.     

Comparison of auditory steady-state response and click-evoked auditory brain response in infants with different types and degrees of hearing loss

Abstract

Background: Auditory steady-state response (ASSR) and click-evoked auditory brain response (c-ABR) have been used for hearing assessment for decades years, the correlation of the two methods and the effects of type and degree of hearing loss (HL) to the correlation in infants younger than 6?months of age are unclear.

Objectives: To compare the correlation of ASSR and c-ABR and then to analyse the effects of type and degree of HL on the correlation in infants younger than 6?months of age.

Material and methods: Retrospective study comparing ASSR thresholds at various frequencies with c-ABR thresholds. 182 ears from 96 infants were assessed and classified according to types and degrees of HL.

Results: The correlation coefficients were: 0.823, 0.864, 0.891, 0.871, 0.908, 0.915 and 0.913 between ASSR thresholds at 0.5, 1, 2, 4, 2–4, 1–2–4, 0.5–1–2–4?kHz and c-ABR thresholds respectively. The correlation coefficients in the group of sensorineural HL (SHL) (r?=?0.763–0.900) were higher than conductive HL (r?=?0.309–0.619) across all frequencies. The coefficients of severe-profound SHL (r?=?0.595–0.790) were higher than mild-moderate SHL (r?=?0.434–0.687) across all frequencies.

Conclusions and significance: ASSR was one valuable cross-check measure by providing frequency specific information in auditory assessment.     

Comparative study between pure tone audiometry and auditory steady-state responses in normal hearing subjects

IntroductionAuditory steady-state responses (ASSR) are an important tool to detect objectively frequency-specific hearing thresholds. Pure-tone audiometry is the gold-standard for hearing evaluation, although sometimes it may be inconclusive, especially in children and uncooperative adults.AimCompare pure tone thresholds (PT) with ASSR thresholds in normal hearing subjects.Materials and methodsIn this prospective cross-sectional study we included 26 adults (n = 52 ears) of both genders, without any hearing complaints or otologic diseases and normal pure-tone thresholds. All subjects had clinical history, otomicroscopy, audiometry and immitance measurements. This evaluation was followed by the ASSR test. The mean pure-tone and ASSR thresholds for each frequency were calculated.ResultsThe mean difference between PT and ASSR thresholdswas 7,12 for 500 Hz, 7,6 for 1000 Hz, 8,27 for 2000 Hz and 9,71 dB for 4000 Hz. There were no difference between PT and ASSR means at either frequency.ConclusionASSR thresholds were comparable to pure-tone thresholds in normal hearing adults. Nevertheless it should not be used as the only method of hearing evaluation.© 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.     

Reliability of electric response audiometry using 80 Hz auditory steady-state responses

The reliability of the Auditory Steady State Response (ASSR) has not been thoroughly evaluated despite its recent application as a clinical tool for threshold estimation. The purpose of this study was to examine test-retest (TR) reliability of ASSR threshold estimates in an empirical research design. The ASSR, tested using modulation frequencies approximately 80 Hz and above, was evaluated against pure tone audiometry (PTA), and the slow vertex potential (SVP, N₁-P₂). Sixteen normal-hearing young female adults were tested twice, one week apart. Varying degrees of sensorineural hearing loss of a notched configuration were simulated with filtered masking noise. Test-retest reliability was assessed using Pearson-product moment correlation analysis, supplemented by other post-hoc analyses. Results demonstrated moderately strong TR reliability for ASSR at 1000, 2000 and 4000 Hz (r?=?0.83–0.93); however, the reliability of ASSR at 500 Hz was weaker (r?=?0.75). Results suggest that ASSR-ERA is a reliable test at mid–high frequencies, at least with the configuration and degrees of simulated sensorineural hearing loss examined in this study.     

40-Hz multiple auditory steady-state responses to narrow-band chirps in sedated and anaesthetized infants

Objective

The general consensus to date has been that a stimulus repetition rate of 40 Hz is not appropriate for the recording of auditory steady-state responses (ASSR) in sedated or anaesthetized infants. The aim of this study was to investigate whether reliable 40-Hz ASSR thresholds can be obtained in sedated infants using narrow-band chirp stimuli in the clinical routine.

Methods

40-Hz auditory brainstem responses (ABR) and 40-Hz ASSR were recorded in 34 infants below the age of 48 months under sedation or under general anaesthesia. ABR were evoked by broad-band chirp stimuli with a flat amplitude spectrum. ASSR were recorded simultaneously from both ears with an adaptive multiple stimulus paradigm using four narrow-band chirps centred at 500, 1000, 2000 and 4000 Hz. ABR and ASSR thresholds were evaluated to determine differences between the estimates from the two methods.

Results

Despite of sedation and anaesthesia, large wave V amplitudes of the chirp evoked 40-Hz ABR were found at levels as low as 10 dB above the individual ABR threshold. ASSR thresholds for stimulus repetition rates of 40 Hz could be consistently estimated in all 34 infants. Thresholds estimated from the ASSR for the four frequencies of the narrow-band chirps and the threshold derived from the broad-band chirp ABR differ, on average by 3.7 dB for the frequency range of 1000–2000 Hz and 7.1 dB for the frequency range from 2000 to 4000 Hz.

Conclusion

In contrast to the general assumption that 40-Hz ASSR are not appropriate for threshold estimation in infants our results demonstrate that multiple ASSR with a stimulus repetition rate of 40 Hz can be recorded in sedated and anaesthetized infants using narrow-band chirps. Threshold estimates obtained with 40-Hz ASSR are, on average, slightly higher than those obtained with chirp evoked ABR but allow for a frequency specific characterisation of the hearing ability.     

Efficacy of combination therapy in adolescent and adult patients with total-deafness sudden sensorineural hearing loss

Background: Combination therapy is the first-line option for total-deafness sudden sensorineural hearing loss (SSNHL). Age may act as a crucial prognostic factor.

Objective: The aim of this study was to compare efficacy of combination therapy between adolescent and adult patients with total-deafness SSNHL.

Materials and methods: Twenty-five adolescent patients (adolescent group) and 106 adult patients (adult group) with total-deafness SSNHL were recruited. All the recruited patients underwent initial treatment with batroxobin, methylprednisolone, and gastrodin. After 10-day treatment, hearing outcomes were determined by pure-tone average measured by audiometry. Moreover, the total effective rates in the hearing recovery and improvement of tinnitus were calculated.

Results: There existed no significant difference between two groups in the total effective rate of the hearing recovery (p?=?.110). However, a significant difference was found in the total effective rate of improvement of tinnitus between two groups (p?=?.016). Both adolescent and adult patients could receive the optimal hearing gains at 500?Hz (20.2?±?13.3 and 23.1?±?13.9dB, respectively), followed by those at 1000?Hz (18.8?±?12.5 and 22.7?±?14.8dB, respectively). Yet, adult patients could get better hearing gains only at 500?Hz than adolescent patients (p?=?.02).

Conclusion: Compared with adult patients, adolescent patients with total-deafness SSNHL undergoing combination therapy may be less likely to have hearing recovery and the improvement of tinnitus.     

Auditory steady-state responses to MM and exponential envelope AM2/FM stimuli in normal-hearing adults

The present study utilized a commercially available multiple auditory steady-state response (ASSR) system to test normal hearing adults (n=55). The primary objective was to evaluate the impact of the mixed modulation (MM) and the novel proposed exponential AM²/FM stimuli on the signal-to-noise ratio (SNR) and threshold estimation accuracy, through a within-subject comparison. The second aim was to establish a normative database for both stimulus types. The results demonstrated that the AM²/FM and MM stimulus had a similar effect on the SNR, whereas the ASSR threshold results revealed that the AM²/FM produced better thresholds than the MM stimulus for the 500, 1000, and 4000 Hz carrier frequency. The mean difference scores to tones of 500, 1000, 2000, and 4000 Hz were for the MM stimulus: 20±12, 14±9, 10±8, and 12±8 dB; and for the AM²/FM stimulus: 18±13, 12±8, 11±8, and 10±8 dB, respectively. The current research confirms that the AM²/FM stimulus can be used efficiently to test normal hearing adults.