Estimation of pure-tone thresholds in adults using extrapolated distortion product otoacoustic emission input/output-functions and auditory steady state responses

Pure-tone thresholds were used as the reference and compared with extrapolated distortion product otoacoustic emission input/output-functions and auditory steady state responses (ASSR) in hearing-impaired adults, using the Cochlea-Scan and Audera devices. Fifty-three subjects presenting sensorineural deficits were included in the study. The DPOAE data were recorded using the detailed Cochlea-Scan threshold modality, and ASSR responses were assessed at 1.0, 2.0, and 4.0 kHz. The comparison between DPOAE and ASSR threshold values indicated significant mean differences across all tested frequencies. Significant relationships were observed between the behavioral and the DPOAE measurements in the lower frequencies (1.5 and 2.0 kHz). The Cochlea-Scan algorithm seems to overestimate hearing threshold. Logistic regression models (probability of DPOAE response p = 0.9), suggested that the identifiable hearing levels are less than 34 dB HL (at 2.0 and 4.0 kHz) and less or equal to 38 and 40 dB HL at 1.5 and 6.0 kHz respectively. The Cochlea-Scan DPOAE protocols can be used in cases presenting mild hearing deficits (i.e.<40 dB HL).     

感音神经性聋儿多频稳态诱发电位及短纯音听性脑干反应与行为测听的相关性

目的 比较多频稳态诱发电位（MASSR）、短纯音听性脑干反应（Tb—ABR）与感音神经性聋儿行为测试听阈的差值．研究MASSR和Tb—ABR反应阈与行为听阈之间是否存在相关性以及在不同听力损失聋儿、不同的频率之间的差异。方法 对60名感音神经性聋儿分别测试MASSR和Tb—ABR反应阈和行为听阈，评价MASSR反应阈、Tb—ABR反应阈与行为听阈的相关性。结果 MASSR反应阈、Tb—ABR反应阈和行为听阈之间均有较高的相关性。二者在频率为2、4kHz时，对行为听阈的预测具有相似的、较高的准确性；但在频率为0．5、1kHz时，MASSR的准确性较Tb—ABR高。结论 MASSR和Tb—ABR均可用作感音神经性聋儿言语频率客观听阈的预测，为低龄儿童及难以检测行为听力的患儿提供诊断依据。     

骨导听觉稳态反应

听觉稳态反应（auditory steady statere sponses，ASSR）是由调制声信号的反应相位与刺激信号相位引起的具有稳定关系的听觉诱发电位。近年来关于ASSR的研究报道较多，其中大部分是关于气导ASSR的研究。然而如同其它听力检测方法．气导测试仅能评估听力损失的程度，不能判断听力损失的类型（如鉴别传导性，感音神经性及混合性聋），如气骨导联合应用可弥补这一缺陷。因此随着ASSR广泛应用于临床，骨导ASSR（BC—ASSR）的研究显得有一定的必要性。本文就骨导ASSR近年来的研究进展及临床应用前景综述如下：     

Human auditory steady state responses: effects of intensity and frequency

Human auditory steady state responses were recorded in 41 normal subjects and 22 patients with hearing loss. The effect of intensity on the responses at different tonal frequencies was assessed using the sweep technique. The amplitude of the responses increases and the phase delay decreases with increasing intensity. Both the amplitude and the phase delay are smaller for high frequency tone bursts. Notched noise decreases the amplitude of the response by a factor of two but does not affect the phase of the responses. Thresholds were estimated in waking subjects using two techniques: intensity sweeps analyzed by linear regressions, and fixed intensities analyzed by Hotelling's T2 test. Frequency-specific thresholds obtained with notched noise were less variable and more accurate with the fixed intensity technique. In patients with sensorineural hearing loss the amplitude increased more with increasing intensity above threshold than in patients with conductive hearing loss.     

Gender and modulation frequency effects on auditory steady state response (ASSR) thresholds

For estimating behavioral hearing thresholds, auditory steady state response (ASSR) can be reliably evoked by stimuli at low and high modulation frequencies (MFs). In this regard, little is known regarding ASSR thresholds evoked by stimuli at different MFs in female and male participants. In fact, recent data suggest that 40-Hz ASSR is influenced by estrogen level in females. Hence, the aim of the present study was to determine the effect of gender and MF on ASSR thresholds in young adults. Twenty-eight normally hearing participants (14 males and 14 females) were enrolled in this study. For each subject, ASSR thresholds were recorded with narrow-band chirps at 500, 1,000, 2,000, and 4,000 Hz carrier frequencies (CFs) and at 40 and 90 Hz MFs. Two-way mixed ANOVA (with gender and MF as the factors) revealed no significant interaction effect between factors at all CFs (p > 0.05). The gender effect was only significant at 500 Hz CF (p < 0.05). At 500 and 1,000 Hz CFs, mean ASSR thresholds were significantly lower at 40 Hz MF than at 90 Hz MF (p < 0.05). Interestingly, at 2,000 and 4,000 Hz CFs, mean ASSR thresholds were significantly lower at 90 Hz MF than at 40 Hz MF (p < 0.05). The lower ASSR thresholds in females might be due to hormonal influence. When recording ASSR thresholds at low MF, we suggest the use of gender-specific normative data so that more valid comparisons can be made, particularly at 500 Hz CF.     

The low and high frequency auditory steady state responses mature at different rates.

The age-related changes in the fast rate (70-110 Hz) auditory steady state response elicited by multiple-frequency tones (MSSR) that were amplitude-modulated (AM) are reported here. The MSSR was recorded in a sample of 64 well babies distributed into three age groups: 0-29 days (n = 25); 1-6 months (n = 26); 7-12 months (n = 13). Four simultaneously presented AM tones (0.5, 1, 2 and 4 kHz) were delivered monaurally through TDH 49 earphones, at different intensities (between 90 and 30 dB SPL). Clear developmental changes were found between birth and 12 months of age in response threshold, amplitude and detectability. Statistical analysis revealed that these changes occurred at different rates for low- and high- frequency responses. Nonetheless adult-like hearing thresholds were estimated reasonably well in most newborns and well babies, for all frequencies tested. Therefore the MSSR technique could be useful for objective frequency-specific audiometry beginning at birth.     

Test accuracy and prognostic validity of multiple auditory steady state responses for targeted hearing screening

The test accuracy and prognostic validity of Multiple Auditory Steady State Responses (MSSR) and click Auditory Brainstem Responses (cABR) was compared within the context of a targeted screening protocol. A sample of 508 high-risk babies was first screened using cABR and MSSR (500 and 2000 Hz). All children (failed/ pass) were called back at three to four years of age to determine their hearing status (pure-tone audiometry). Although both methods showed an equally good test performance in the first screen (sensitivity: 100% and specificity: 92-95%), the MSSR may have some potential advantage to identify low-frequency hearing loss. Furthermore, the confirmatory audiometry with MSSR predicted the child hearing status more accurately than the cABR. In conclusion, the MSSR can provide valuable information for the diagnosis and management of infants earlier detected by a screening protocol and further developed might be also useful as a screening test.     

Test accuracy and prognostic validity of multiple auditory steady state responses for targeted hearing screening

The test accuracy and prognostic validity of Multiple Auditory Steady State Responses (MSSR) and click Auditory Brainstem Responses (cABR) was compared within the context of a targeted screening protocol. A sample of 508 high-risk babies was first screened using cABR and MSSR (500 and 2000?Hz). All children (failed/pass) were called back at three to four years of age to determine their hearing status (pure-tone audiometry). Although both methods showed an equally good test performance in the first screen (sensitivity: 100% and specificity: 92–95%), the MSSR may have some potential advantage to identify low-frequency hearing loss. Furthermore, the confirmatory audiometry with MSSR predicted the child hearing status more accurately than the cABR. In conclusion, the MSSR can provide valuable information for the diagnosis and management of infants earlier detected by a screening protocol and further developed might be also useful as a screening test.

Sumario

Se comparó la eficiencia diagnóstica y el valor pronóstico de los potenciales evocados auditivos de estado estable a múltiples frecuencias (MSSR, siglas en inglés) con los potenciales evocados auditivos de tallo cerebral con clicks (cABR, siglas en inglés) en el contexto de un programa de tamizaje auditivo de niños con factores de riesgo. Inicialmente se realizó un tamizaje con cABR y MSSR (0.5 y 2 kHz) a una muestra de 508 bebés de alto riesgo. Todos los niños (los que pasaron y los que fallaron) se reevaluaron a los 3 o 4 años de edad para determinar su estado auditivo (audiometría tonal). Aunque los dos métodos mostraron igualmente buen desempeño en el primer tamizaje (sensibilidad: 100% y especificidad: 92–95%) los MSSR pueden tener una ventaja potencial para identificar hipoacusias en tonos graves. Además la prueba audiométrica confirmatoria con MSSR predijo el status auditivo del niño con mas precisión que los cABR. En conclusión, los MSSR pueden proporcionar información valiosa para el diagnóstico y tratamiento de niños previamente detectados por un programa de tamizaje y en un futuro pueden ser también útiles como prueba de tamizaje.     

Masked and unmasked pure-tone thresholds of infants and adults: development of auditory frequency selectivity and sensitivity

Detection thresholds for pure tones (1000 Hz and 4000 Hz) in noise and in quiet were estimated for infants at 6 months and 12 months of age and for adults. A visually reinforced head-turn procedure under control of a PDP-11/03 minicomputer was used. An adaptive protocol with a 5-dB step size was employed for the threshold estimates. Infant thresholds were poorer than adult thresholds in each condition. In noise, infant-adult differences were 8 dB (6-month-old infants) and 6 dB (12-month-old infants) at each frequency. In quiet, infant-adult differences were 14 dB (6-month-old infants) and 12 dB (12-month-old infants) at 1000 Hz but were only 7 dB (6-month-old infants) and 5 dB (12-month-old infants) at 4000 Hz. The masking data suggest that infants are at only a slight disadvantage in detecting a target in a background of noise and are consistent with a frequency selectivity mechanism that is proportional to that of adults. The detection-in-quiet data, with greater correspondence among the groups at 4000 Hz than at 1000 Hz, support the notion that hearing sensitivity varies with frequency in a different way in infants than in adults. Data on task performance reveal significant age effects, and the possibility that such effects have biased the observed differences in the estimates of sensory function among the groups is considered.     

Using multi-stimulus auditory steady state response to predict hearing thresholds in high-risk infants

The purpose of this study was to investigate whether multi-stimulus auditory steady-state responses were capable of estimating hearing thresholds in high-risk infants. A retrospective chart review study. Three tertiary referral centers. Infants born between January 2004 and December 2006 who met the criteria for risk factors of congenital hearing loss were enrolled in the study. While under sedation, the multi-stimulus auditory steady-state response was used to determine multi-channel auditory steady-state response thresholds for high-risk infants younger than 13 months. Conditioned play audiometry was then applied to these children at 23–48 months of age to obtain pure tone audiograms. Auditory steady-state response thresholds and pure tone thresholds were then compared. A total of 249 high-risk infants were enrolled in the study. 39 infants were lost during follow-up. The remaining 216 infants completed both examinations. The Pearson correlation coefficients (r) between the ASSR levels and pure tone thresholds were 0.88, 0.94, 0.94 and 0.97 at 500, 1,000, 2,000 and 4,000 Hz, respectively. The strength of the relationship between the auditory steady-state responses and pure tone thresholds increased with more severe degrees of hearing loss and higher frequencies. We conclude that initial multichannel ASSR thresholds measured under sedation are highly correlated with pure tone thresholds obtained 2 or 3 years later. ASSR can be used to predict the frequency-specific hearing thresholds of high-risk infants and can provide information for early hearing intervention.     

客观评价听觉稳态反应技术在临床中的应用

听觉稳态反应（auditory steady state responses，ASSR），或多频稳态电位（multiple frequency steady state responses，Mf SSR），现又被称为多频听觉稳态反应（multiple frequency auditory steady state response，Mf ASSR）是一种新的电生理测试技术。考虑到与国际研究术语一致的必要，本文将使用“听觉稳态反应”这个词，英文的缩写是ASSR。听觉稳态反应由于具有许多短声听性脑干反应（click ABR）在估测听力阈时没有具备的优点．如自动测试和判断测试反应、更高的频率相关性、高刺激声强度并且和行为测听的阈值有较好的可比性等，已经在国内外得到广泛的临床应用。在国内，我们陆续看到许多介绍和研究听觉稳态反应在临床应用的报告。积极引进国外先进技术并迅速应用到临床上去，     

Human auditory steady state potentials

The auditory steady state potentials may be an important technique in objective audiometry. The effects of stimulus rate, intensity, and tonal frequency on these potentials were investigated using both signal averaging and on-line Fourier analysis. Stimulus presentation rates of 40 to 45/sec result in a 40 Hz sinusoidal response which is about twice the amplitude of the 10 and 60/sec responses. No significant effects of subject age or sex were seen. The 40/sec response shows a linear decrease in amplitude and a linear increase in latency when stimulus intensity is decreased from 90 to 20 dB normal hearing level. This response is recordable to within a few decibels of behavioral threshold. Stimuli of different tonal frequency give similar amplitude/rate functions, with absolute amplitude decreasing with increasing tonal frequency. Signal averaging and Fourier analysis provide nearly identical amplitude/rate, amplitude/intensity, and latency/intensity functions. Both methods of analysis may be used, therefore, to record the 40 Hz steady state potential. Fourier analysis, however, may be the faster and less expensive method. Furthermore, techniques ("zoom") are available with Fourier analysis to study the effects of varying stimulus parameters on-line with the Fourier analysis procedure.     

多频稳态诱发电位和听性脑干反应对感音神经性聋儿童客观听阈的评估

目的比较多频稳态诱发电位(MASSR)与短纯音听性脑干反应(Tb-ABR)对感音神经性聋儿童客观听阈的评估。方法对37名感音神经性聋儿童分别测试MASSR反应阈、Tb-ABR反应阈和行为听阈,参照行为听阈,比较MASSR反应阈和Tb ABR反应阈对行为听阈评估的准确性。结果MASSR反应阈、Tb-ABR反应阈和行为听阈之间均有较高的相关性。二者在频率为2、4kHz时,对行为听阈的评估具有相似的准确性;但在频率为0.5、1kHz时,MASSR的准确性较Tb ABR的准确性高。结论MASSR和Tb-ABR均可用作感音神经性聋儿童言语频率客观听阈的评估,但MASSR在低频(0.5、1kHz)时较Tb-ABR的准确性高。     

Refining the audiological assessment in children using narrow-band CE-Chirp-evoked auditory steady state responses

Objective: To demonstrate the feasibility and reliability of simultaneous binaural recording of auditory steady-state responses (ASSR) in young children using narrow-band CE-Chirps as stimuli. Design: Prospective cohort study comparing ASSR thresholds to four frequency stimuli (0.5, 1, 2, and 4 kHz), with click-evoked auditory brainstem responses (ABR) and behavioral response audiometry. Study sample: Thirty-two young children (mean age 7.4 ± 5.2 months) referred for auditory assessment were evaluated. Results: The mean duration for ABR recordings was 13.3 ± 7.2 min versus 22.9 ± 15.8 min for ASSR (p < 0.01). ASSR (means of 2 and 4 kHz thresholds) were highly correlated with ABR thresholds (R² = 0.935, p < 0.001), though significantly different (3 ± 10.7 dB, p = 0.02). ASSR (means of 0.5, 1, 2, and 4 kHz thresholds) were highly correlated with mean behavioral response audiometry thresholds (R² = 0.968, p < 0.001). ASSRs were highly and significantly correlated with behavioral response audiometry at 0.5, 1, 2, and 4 kHz (R² = 0.845, 0.907, 0.929, and 0.859 respectively, p < 0.001). 87.5% and 90.7% ASSR thresholds were within a ± 10 dB range around their corresponding ABR and mean behavioral response audiometry thresholds. Conclusions: Narrow-band CE-Chirps allow a fast and reliable assessment of auditory thresholds in children, especially in the low-frequency range, by comparison with other stimuli.     

Estimating audiometric thresholds using auditory steady-state responses

Human auditory steady-state responses (ASSRs) were recorded using stimulus rates of 78-95 Hz in normal young subjects, in elderly subjects with relatively normal hearing, and in elderly subjects with sensorineural hearing impairment. Amplitude-intensity functions calculated relative to actual sensory thresholds (sensation level or SL) showed that amplitudes increased as stimulus intensity increased. In the hearing-impaired subjects this increase was more rapid at intensities just above threshold ("electrophysiological recruitment") than at higher intensities where the increase was similar to that seen in normal subjects. The thresholds in dB SL for recognizing an ASSR and the intersubject variability of these thresholds decreased with increasing recording time and were lower in the hearing impaired compared to the normal subjects. After 9.8 minutes of recording, the average ASSR thresholds (and standard deviations) were 12.6 +/- 8.7 in the normal subjects, 12.4 +/- 11.9 dB in the normal elderly, and 3.6 +/- 13.5 dB SL in the hearing-impaired subjects.