扩散场中正常青年人扩展低频听阈测试的初步报告

应用我们建立的扩展低频测听系统，在扩散声场内测量了３０名斜正常青年人４０Ｈｚ－１２５Ｈｚ纯音听阈。结果表明，在此频段正常人听阈随测试频率增加而降低。且所有受试者阈值沿其算术均数正态分布。本文结果同ＩＳＯ２２６－１９８７及其他学者有关报告进行比较。     

扩散场中正常青年人扩展低频听阈测试的初步报告

应用我们建立的扩展低频测听系统，在扩散声场内测量了３０名耳科正常青年人４０Ｈｚ～１２５Ｈｚ纯音听阈。结果表明，在此频段正常人听阈随测试频率增加而降低，且所有受试者阈值沿其算术均数成正态分布。本文结果同ＩＳＯ２２６－１９８７及其他学者有关报告进行了比较。     

扩展低频测听系统的建立及正常青年人低频阈声压级

通过对临床声场听室的声学改造、校正、，应用低频信号发生系统和测量装置，共同组成扩展低频测听系统。经测试表明，该系统本底噪声小、低频区频率稳定性好、４０－１２５Ｈｚ最大输出达９５－１１０ｄＢＳＰＬ。利用上述系统测量了３０名耳科正常青年人扩展低频声场听阈，结果与ＩＳＯ２２６（１９８７）及国外近年来报告基本一致。     

短音诱发听性脑干反应的特性观察

目的 了解短音（tone pip）诱发的听性脑干反应（TP－ABR）的特征及其各频率反应阈与纯音听阈的关系。方法 对正常听力青年人30耳分别采用短声（click）、短音（0.5、1、2、4、6、8kHz）测试，记录各自不同强度下ABR的波形，观察V波潜伏期的改变。结果 tone pip与常规click声诱发的ABR极为相似，均有很高的可重复性和可靠性；ABR反应阈均较其主观听阈高，尤其是频率越低，反应阈越高，低频个体差异较大；随频率（0.5-8kHz）和强度（40－120dB peSPL）增加Ⅰ波Ⅴ潜伏期递减；各频率的反应阈与音听阈均有较好的相关性。结论 短音刺激记录的TP－ABR具有频率特性，其反应阈在相应频率的客观听力评估中有应用价值。     

不同人群高频听力测试结果分析

目的 通过测试不同年龄段常频听力正常受试者的高频听阈，从而获得高频听力的正常值。方法 2002年2月～2003年12月，对常频听力正常的受试者进行了高频测听。按国际标准将符合条件的受试者分为青年组和成年组，青年组160名，年龄在18-25岁之间，平均21．7岁，其中男96名，女64名；成年组192名，并按照10岁为一个年龄段分为25～岁，35～岁，45～岁．55～岁和65～岁5个小组，每组均行双耳常频和高频听阈测试，计算高频各频率的检出率，并对检查结果运用SPSS10．0统计软件分别进行方差分析和x^2检验。结果 青年组常频听力测试在各频率均〈25dB HL，在4000，6000和8000Hz处的听阈略高（P〈0．05）；成年组常频区的听力测试在各频率均≤25dB HL，但随着年龄的增长，听阈值有逐渐提高的趋势（P〈0．05）。将青年组和成年组受试者按照性别分类，发现女性受试者的听力比男性的好（P〈0．05）。高频听力测试显示正常青年组的听阈随频率的增高而增高（P〈0．05），同时对于各个频率，随年龄的增长听阈也逐渐提高（P〈0．05）。结论 本研究获得了青年人以及不同年龄段成年人的常频和高频听阈均值及其性别差异。     

耳科正常人听阈与年龄的相关性分析

目的 探究耳科正常人低频（0.125kHz、0.25kHz）、言语频率（0.5kHz、1kHz、2kHz、4kHz）、高频（3kHz、4kHz、6kHz、8kHz）和扩展高频（9kHz、10kHz、11.2kHz、12.5kHz、14kHz、16kHz）纯音听阈与年龄相关的发展趋势。方法 分别对各年龄符合纳入标准的受试者（n=106）进行双耳纯音听阈测试。将纯音测听结果按照低频（0.125kHz、0.25kHz）、言语频率（0.5kHz、1kHz、2kHz、4kHz）、高频（3kHz、4kHz、6kHz、8kHz）、扩展高频（9kHz、10kHz、11.2kHz、12.5kHz、14kHz、16kHz）分为四个组。在以上每个频率组中分别以年龄为横坐标,纯音阈值为纵坐标绘制散点图,观察纯音阈值的发展与“拐点”出现情况。再按照年龄18-25岁、26-35岁、36-45岁、46-55岁、56-65岁、66-75岁、≥76岁分为以上7个组,以年龄组为自变量进行多元线性回归分析。结果 观察散点图发现,随年龄上升各频率组纯音阈值均有增长趋势,且随着频率的增加,纯音阈值增长的“拐点”逐渐提前并趋于年...     

1kHz短纯音诱发40Hz听觉相关电位的频率特性(摘要)

１ｋＨｚ短纯音诱发４０Ｈｚ听觉相关电位的频率特性（摘要）于黎明顾瑞姜泗长听性脑干反应（ＡＢＲ）临床应用十分广泛，但由于用短声刺激记录的ＡＢＲ主要反映高频（３ｋＨｚ左右）的听阈，对平坦型听力下降者阈值与纯音听阈一致；当有高频听力下降时，其阈值往往过高；...     

扩展高频测听在噪声性听力损失早期诊断中的应用

目的 探讨扩展高频测听（１０－２０ｋＨｚ）在噪声性听力损失早期诊断中的作用及不同年龄,工龄,暴露噪声的强度与１０－２０ｋＨｚ听阈损失的关系。方法 应用频率范围为０．５－２０ｋＨｚ的纯音听力计对１０００名噪声下作业工人的听力进行检测,以１２０名不同年龄的健康人作为对照组,结果在９５－１１５ｄＢ（Ａ）的噪声强度下,当０．５～６ｋＨｚ的阈值未出异常时,１０－１８ｋＨｚ的阈值明显高于对照９５－１１５ｄＢ（     

扩展高频测听的临床分析

目的：使用临床听力计ＡＣ－４０以ｄＢＨＬ表示，与纯音测听的零级标准单位一致。观察实验条件下扩展高频测听以ｄＢＨＬ表示的阈值特征与以往报道的阈值（以ｄＢＳＰＬ为单位）的规律是否一致。方法：纯音测听和耳镜检查正常受试者２２７例，男１１２例，女１１５例，共４４５耳，左２２３耳，右２２２耳。年龄１７～８７岁，每隔１０岁为一年龄组，共分为７组，使用丹麦奥迪康ＡＣ－４０型听力计进行扩展高频听力测试。结果：扩展高频测听的阈值随频率的增高而增高，１１ｋＨｚ以上的阈值增加幅度明显增大；阈值随年龄的增高而增高，３０～４０岁年龄组以上者阈值幅度增高明显；在听力计最大输出强度，从较低频率到较高频率，随年龄的增大，则给声信号的检出率逐渐下降；３０～４０岁以下年龄组各频率的检出率为１００．０％，而７０岁以上年龄组在１６ｋＨｚ的检出率只有１６．０％；受试者之间阈值变化的差异也因频率和年龄而表现不同的特征；１１～１４ｋＨｚ之间阈值的变化的差异最大，１４ｋＨｚ以下各频率阈值变化的差异随年龄的增高而增高，其中３１～４０岁年龄组变化最大；双耳间阈值差范围在０ｄＢＨＬ～８．７ｄＢＨＬ之间，绝大多数在５ｄＢＨＬ以下，Ｐ＞０．０５，差别无显著性，说     

正常人扩展高频测听阈值的研究

目的探讨不同年龄正常人扩展高频测听阈值以标准零级为听力计0dB时的变化特点。方法对131名正常人(21～印岁)按10岁为一组分组，分别测定扩展高频听阈值。听力评价应用ORBITER922—2听力计(Madsen，丹麦)，频率范围0．125～20kHz。结果①各年龄组扩展高频听阈的平均阈值随测听频率和年龄的增加而增加；②各年龄组阈值的检出率随测听频率以及年龄的增加呈下降趋势。结论①正常人的高频测听阈值与年龄及测听频率呈正相关。②高频听阈左右耳及性别间无显著性差异。     

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).     

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.     

多频听觉稳态反应与40Hz听相关电位对儿童客观听阈评估的比较

目的通过对感音神经性聋患儿的多频听觉稳态反应（multiple frequency auditory steady--state response，MFASSR）测试结果进行分析，并比较其在0．5 kHz处与40 Hz听相关电位（40Hz auditory event related potential，40 Hz AERP）对客观听阈评估的准确性，为MFASSR临床应用提供指导。方法对感音神经性聋儿进行纯音测听、ABR、40 Hz AERP和MFASSR测试。MFASSR与ABR、40 Hz AERP测试均在睡眠状态下进行。按照测试结果分为ABR未引出组与ABR引出组。结果①MFASSR在0．5 kHz处引出率比40 Hz AERP低。②0．5 kHz MFASSR反应阈对纯音听阈的评估较1、2、4 kHz MFASSR反应阈对纯音听阈的评估差。③以纯音听阈为标准，在0．5 kHz处MFASSR与40 Hz AERP对纯音听阈的评估差别具有统计学意义（P=0．001），说明，在0．5 kHz处MFASSR对纯音听阈评估的准确性不如40 Hz AERP。结论MFASSR反应阈对0．5 kHz处纯音听阈的预测需要结合40 Hz AERP来判断。     

Cochleo-vestibular correlations in Meniere's disease.

The cochlear and vestibular functions were investigated in a sample of 36 patients with unilateral Meniere's disease. Caloric reactions and hearing thresholds were compared separately at several frequencies. A topodiagnostic relationship between the cochlear and vestibular function was discovered. Using four qualitative categories, a significantly high correlation was obtained between the basal hearing loss (4000 Hz) and unilateral weakness, whereas no correlation was obtained when evaluating the more apical hearing loss (lower frequencies 250-1 000 Hz). A normal caloric reaction can be reasonably expected in cases of unilateral Meniere's disease if the hearing loss is less than approx. 40 dB HL at 4 000 Hz.     

Effect of low-frequency gain and venting effects on the benefit derived from directionality and noise reduction in hearing aids

When the frequency range over which vent-transmitted sound dominates amplification increases, the potential benefit from directional microphones and noise reduction decreases. Fitted with clinically appropriate vent sizes, 23 aided listeners with varying low-frequency hearing thresholds evaluated six schemes comprising three levels of gain at 250 Hz (0, 6, and 12 dB) combined with two features (directional microphone and noise reduction) enabled or disabled in the field. The low-frequency gain was 0 dB for vent-dominated sound, while the higher gains were achieved by amplifier-dominated sounds. A majority of listeners preferred 0-dB gain at 250 Hz and the features enabled. While the amount of low-frequency gain had no significant effect on speech recognition in noise or horizontal localization, speech recognition and front/back discrimination were significantly improved when the features were enabled, even when vent-transmitted sound dominated the low frequencies. The clinical implication is that there is no need to increase low-frequency gain to compensate for vent effects to achieve benefit from directionality and noise reduction over a wider frequency range.     

Effect of low-frequency gain and venting effects on the benefit derived from directionality and noise reduction in hearing aids

When the frequency range over which vent-transmitted sound dominates amplification increases, the potential benefit from directional microphones and noise reduction decreases. Fitted with clinically appropriate vent sizes, 23 aided listeners with varying low-frequency hearing thresholds evaluated six schemes comprising three levels of gain at 250 Hz (0, 6, and 12 dB) combined with two features (directional microphone and noise reduction) enabled or disabled in the field. The low-frequency gain was 0 dB for vent-dominated sound, while the higher gains were achieved by amplifier-dominated sounds. A majority of listeners preferred 0-dB gain at 250 Hz and the features enabled. While the amount of low-frequency gain had no significant effect on speech recognition in noise or horizontal localization, speech recognition and front/back discrimination were significantly improved when the features were enabled, even when vent-transmitted sound dominated the low frequencies. The clinical implication is that there is no need to increase low-frequency gain to compensate for vent effects to achieve benefit from directionality and noise reduction over a wider frequency range.     

Comparison of hearing-aid gain using functional, coupler, and probe-tube measurements

Measurements of functional gain were compared first to coupler gain for 57 subjects using one of three hearing aid-earmold combinations and second to probe-tube gain for 12 subjects using in-the-ear hearing aids. The average difference between functional and coupler gain plotted as a function of frequency yielded results that were similar to previous reports, with the greatest effects occurring at 3000 and 4000 Hz. Significant differences were seen among hearing aid-earmold combinations at 3000, 4000, and 6000 Hz. Standard deviations for measurements between 750 and 2000 Hz were less than 5 dB and could be explained by variability of functional gain measures associated with test-retest variability of thresholds measured in a sound field. Below 750 Hz and above 2000 Hz, standard deviations exceeded 5 dB. The greater variability may be explained by differences in earmold venting, acoustic characteristics of the ear canal, and stimuli used to measure functional and coupler gain. Neither room nor hearing-aid noise appeared to affect the results significantly. When functional gain was compared to insertion gain measured with a probe-tube system, the average difference across frequencies was less than 1 dB. The variability of the differences at all frequencies, with the exception of 6000 Hz, was within the range reported for functional gain measurements. It was concluded that functional gain can be accurately estimated using probe-tube measurements.     

Relationship between transducer type and low-frequency hearing loss for patients with ventilation tubes

OBJECTIVE: To determine the relationship between the type of transducer used to perform pure-tone audiometry and the appearance of low-frequency hearing loss at 250Hz and 500Hz for patients with ventilation tubes. METHODS: Air conduction thresholds at 250Hz and 500Hz were measured using Telephonics TDH-49 supra-aural headphones and EARTONE 3-A insert earphones for patients with normal ears (N=16) and patients with ventilation tubes (N=114). Tympanometry was performed on each patient prior to audiometric testing. Audiometric test results obtained in normal ears were compared to results for patients with ventilation tubes. For analysis, the ventilation tube patients were separated into two groups, representative of ventilation tube type. RESULTS: Audiometric results obtained using the two transducer types at 250Hz and 500Hz revealed significant differences in threshold for patients with ventilation tubes. Thresholds obtained using insert earphones were generally worse than thresholds obtained using supra-aural headphones for this group. On average, difference in threshold was 14.15dB worse with insert earphones at 250Hz and 9.75dB worse with insert earphones at 500Hz for patients with Sheehy tubes. Average difference in threshold for patients with Donaldson tubes was 13.93dB worse with insert earphones at 250Hz and 8.93dB worse with insert earphones at 500Hz. In addition, thresholds were more variable for patients with ventilation tubes than normal ears at 500Hz. There were no significant differences in threshold for normal ears using both transducers. CONCLUSIONS: When performing pure-tone audiometry, choice of transducer can influence the accurate identification of a low-frequency hearing loss in patients with ventilation tubes. Low-frequency thresholds were generally worse using insert-style earphones to test subjects with tubes, resulting in the apparent identification of a hearing loss. However, with supra-aural headphones, no low-frequency hearing loss existed. There were no significant differences in threshold values using either transducer in normal ears.     

Brain stem response audiometry at speech frequencies

Auditory-evoked brain stem response (BSR; wave V) was studied, using tone pips at three speech frequencies (500, 1 000 and 2 000 Hz) as stimuli. The tone pips consisted of 5-ms rise-decay times without a plateau. BSR recordings were made in 10 normal subjects and in 16 subjects with impaired hearing. In the normal subjects, BSR thresholds ranged from 10 to 20 dB SL at these three frequencies. In the subjects with impaired hearing, BSR thresholds corresponded well to conventional pure-tone thresholds at each frequency in cases of low- as well as high-frequency hearing loss. In all subjects with impaired hearing, the BSR thresholds were higher by as much as 25 dB than the pure-tone thresholds. The mean differences between these two thresholds at 500, 1 000 and 2 000 Hz were 11.3 ± 8.0, 10.9 ± 6.2 and 10.9 ± 7.3 dB, respectively.

Thus, we conclude that the BSR is useful for objective assessment of hearing thresholds at each of these speech frequencies.     

Using a combination of click- and tone burst-evoked auditory brain stem response measurements to estimate pure-tone thresholds

DESIGN: A retrospective medical record review of evoked potential and audiometric data were used to determine the accuracy with which click-evoked and tone burst-evoked auditory brain stem response (ABR) thresholds predict pure-tone audiometric thresholds. METHODS: The medical records were reviewed of a consecutive group of patients who were referred for ABR testing for audiometric purposes over the past 4 yrs. ABR thresholds were measured for clicks and for several tone bursts, including a single-cycle, Blackman-windowed, 250-Hz tone burst, which has a broad spectrum with little energy above 600 Hz. Typically, the ABR data were collected because the patients were unable to provide reliable estimates of hearing sensitivity, based on behavioral test techniques, due to developmental level. Data were included only if subsequently obtained behavioral audiometric data were available to which the ABR data could be compared. Almost invariably, the behavioral data were collected after the ABR results were obtained. Because of this, data were included on only those ears for which middle ear tests (tympanometry, otoscopic examination, pure-tone air- and bone-conduction thresholds) indicated that middle ear status was similar at the times of both tests. With these inclusion criteria, data were available on 140 ears of 77 subjects. RESULTS: Correlation was 0.94 between click-evoked ABR thresholds and the average pure-tone threshold at 2 and 4 kHz. Correlations exceeded 0.92 between ABR thresholds for the 250-Hz tone burst and low-frequency behavioral thresholds (250 Hz, 500 Hz, and the average pure-tone thresholds at 250 and 500 Hz). Similar or higher correlations were observed when ABR thresholds at other frequencies were compared with the pure-tone thresholds at corresponding frequencies. Differences between ABR and behavioral threshold depended on behavioral threshold, with ABR thresholds overestimating behavioral threshold in cases of normal hearing and underestimating behavioral threshold in cases of hearing loss. CONCLUSIONS: These results suggest that ABR thresholds can be used to predict pure-tone behavioral thresholds for a wide range of frequencies. Although controversial, the data reviewed in this paper suggest that click-evoked ABR thresholds result in reasonable predictions of the average behavioral thresholds at 2 and 4 kHz. However, there were cases for which click-evoked ABR thresholds underestimated hearing loss at these frequencies. There are several other reasons why click-evoked ABR measurements were made, including that they (1) generally result in well-formed responses, (2) assist in determining whether auditory neuropathy exists, and (3) can be obtained in a relatively brief amount of time. Low-frequency thresholds were predicted well by ABR thresholds to a single-cycle, 250-Hz tone burst. In combination, click-evoked and low-frequency tone burst-evoked ABR threshold measurements might be used to quickly provide important clinical information for both ends of the audiogram. These measurements could be supplemented by ABR threshold measurements at other frequencies, if time permits. However, it may be possible to plan initial intervention strategies based on data for these two stimuli.