短声作为刺激声同侧声发射阈测定之临床价值

OBJECTIVE: To define that click can substitute for pure tone as a stimulus to measure ipsilateral acoustic reflex thresholds, and to find out the effect of probe frequency on acoustic reflex thresholds. METHOD: Using middle ear analyzer (GSI 33, version 2), we measured 23 normal voluntary participants (46 ears) for getting the pure-tone generated ipsilateral acoustic reflex thresholds at different probe frequency and the click evoked ipsilateral acoustic reflex thresholds at click rate 100/s and 180/s for every ear. RESULT: For pure tone, the ipsilateral acoustic reflex thresholds at 500 Hz, 1000 Hz, 2000 Hz, were (84.35 +/- 6.96) dB, (84.65 +/- 5.93) dB, (87.96 +/- 6.36) dB by using 226 Hz probe; (93.13 +/- 6.54) dB, (92.70 +/- 6.33) dB, (93.35 +/- 5.99) dB by using 678 Hz probe; (86.52 +/- 4.72) dB, (87.48 +/- 5.00) dB, (88.30 +/- 6.16) dB by using 1000 Hz probe. For click, the ipsilateral acoustic reflex thresholds at click rate 100/s and 180/s were (89.78 +/- 6.83) dB, (92.07 +/- 7.42) dB by using 226 Hz probe; (90.44 +/- 6.76) dB, (90.65 +/- 6.38) dB by using 678 Hz probe; (88.04 +/- 6.87) dB, (88.69 +/- 7.42) dB by using 1000 Hz probe. The acoustic reflex thresholds for 678 Hz probe were higher than those obtained with 226 Hz and 1000 Hz probes. CONCLUSION: There were no artifact appearance while stimulus had been click at low rate, so click can be used for the measurement of ipsilateral acoustic reflex thresholds.     

High- and Low-Frequency Probe Tone Tympanometry in Chinese Infants

Objective To assess the utility of low- and high-frequency tympanometry in the diagnosis of middle ear dysfunction in Chinese infants. Methods Tympanograms were obtained with 226 Hz, 678 Hz and 1000 Hz probe tones from infants aged 5-25 weeks with normal auditory brainstem responses (ABRs)(15 infants,30 ears) and withprolonged wave Ⅰ latencies(17 infants, 20 ears), suggesting middle ear dysfunction, using a GSI Tympstar middle ear analyzer Version Ⅱ. Results The single-peaked tympanogram was the most characteristic type in both groups and seen in 25 ears (83.3%) in the normal ABR group and in 18 ears (90%) in the delayed wave Ⅰ group, respectively. The peak pressure, peak compensated static acoustic admittance and gradient of 226 Hz tympanometry were of no significant differences between the two groups. The 678 Hz tympanograms of admittance, susceptance and conductance demonstrated non-peak, single-, double- and tri-peaked patterns in both groups. The agreement between ABRs and 678 Hz tympanograms of admittance,susceptance and conductance were 70.0%, 58.0% and 64.0%(kappa=0.324, 0.234 and 0.118) respectively. For 1000 Hz probe tone, admittance,susceptance and conductance tympanograms showed single peaked patterns in 28 (93.3%), 25 (83.3%) and 26 (86.7%) of the 30 normal ears. Admittance, susceptance and conductance tympanograms using the 1000 Hz probe tone were flat in 15 (75%), 17(85%) and 13 (65%) of the ears in infants with prolonged wave Ⅰ latencies. For 1000 Hz admittance, susceptance and conductance Tympanograms, the agreement between tympanometry and ABR results were 90.0%, 92.0% and 86.0% with kappa at 0.783, 0.831 and 0.690, respectively. Conclusion 1000 Hz probe tone tympanometry is a promising middle ear function test for infants of 1-6 months age, while 226 Hz and 678 Hz probe tones are less efficient in detecting middle ear dysfunction in infants.     

低频和高频探测音鼓室声导抗测试在婴儿中耳功能诊断中的作用

目的评价低频和高频探测音鼓室声导抗测试在诊断婴儿中耳功能异常中的作用。方法使用GSI Tympstar中耳分析仪，对年龄5—25周的听性脑干反应（auditory brainstem response，ABR）检查正常婴儿15例（30耳）和Ⅰ波潜伏期延长提示可能存在中耳功能异常婴儿17例（20耳），进行226、678、1000Hz探测音鼓室声导抗测试的比较。结果226Hz探测音鼓室声导纳图的静态声导纳值、图形、峰压和梯度在2组间的差异无统计学意义。678Hz探测音鼓室声导纳图、声纳图及声导图在2组中均可见无峰型、单峰型、双峰型、三峰型图形，其与ABR检查的一致率分别为70．0％、58．0％、64．0％，kappa值分别为0．324、0．234、0．118。1000Hz探测音鼓室声导纳图、声纳图及声导图在正常组中单峰型分别为28耳（93．3％）、25耳（83．3％）、26耳（86．7％），在异常组中无峰型分别为15耳（75％）、17耳（85％）、13耳（65％），其与ABR的一致率分别为90．0％、92．0％、86．0％，kappa值分别为0．783、0．831、0．690。结论1000Hz探测音鼓室声导抗测试是诊断小于25周婴儿中耳功能的较准确的检查方法，226、678Hz探测音鼓室声导抗测试则不能提供这些婴儿中耳功能的准确的信息。     

Tympanometric and acoustic-reflex studies in neonates

Tympanograms and acoustic reflexes for a broadband noise and for a 1000-Hz tone were measured in normal neonates. Notched tympanograms were typical of neonatal ears for a 220-Hz probe tone. A single-peaked tympanogram was most characteristic for a probe frequency of 660 Hz. Ipsilateral and contralateral acoustic reflexes were present more frequently for a 660-Hz probe tone compared to a 220-Hz probe tone, but acoustic-reflex thresholds were not significantly different between probe tones. As with adults, acoustic-reflex thresholds for the noise were significantly lower than for the tone, and ipsilateral reflex thresholds were lower than contralateral reflex thresholds. Reliability of acoustic-reflex and tympanometric measures was high. Age change from 2 to 4 days had no significant effect on tympanometric or acoustic-reflex characteristics. There was no apparent relation between tympanometric pattern and acoustic-reflex characteristics.     

The effects of probe-tone frequency on the acoustic-reflex growth function

Acoustic-reflex growth functions (ARGFs) were obtained from 20 normal-hearing listeners. Contralateral acoustic reflexes (ARs) were elicited with pure tones of 2000 Hz. The magnitude of changes in static compliant susceptance (BA) and conductance (GA) were monitored with probe-tone frequencies of 226 Hz, 678 Hz and 1000 Hz. ARGFs were obtained with six combinations of probe-tone frequency/admittance component: 226 Hz BA, 226 Hz GA, 678 Hz BA, 678 Hz GA, 1000 Hz BA, and 1000 Hz GA. Peak conductance (GA) and susceptance (BA) ARs were largest within the 678 Hz GA and 1000 Hz BAARGFs, respectively. Among high-frequency probe tones, the patterns of AR growth were larger and less variable for the 678 Hz GA ARGF and the 1000 Hz BA ARGF as determined by the magnitude of their linear (b1) and quadratic (b2) polynomial coefficients and the value of their squared correlation coefficients (R2).     

足月正常新生儿多频探测音鼓室声导抗正常值测定

目的：探讨正常新生儿多频探测音鼓室声导抗图的图型、声导纳值、声纳值和声导值的正常范围。方法：使用GSI-33中耳分析仪,对足月顺产并通过瞬态诱发性耳声发射和畸变产物耳声发射筛查的新生儿55例（110耳）进行226、6781、000 Hz探测音鼓室声导抗测试,对比分析各种探测音鼓室声导抗的图形,声导纳值、声纳值和声导值,并进行统计学分析。结果：226 Hz探测音鼓室声导纳图、声纳图和声导图以双峰型为主,分别占90.0%、99.1%和85.5%,少数为单峰型,无多峰型出现;678 Hz探测音鼓室声导纳图、声纳图和声导图以单峰型为主,分别占62.7%、77.3%和62.7%,双峰型分别占34.6%、20.9%和31.8%,少数出现三峰型;1 000 Hz探测音鼓室声导纳图、声纳图和声导图以单峰型为主,分别占96.4%、99.1%和97.3%,极少数为双峰型,无三峰型出现。226 Hz与678 Hz探测音测试,鼓室声导纳值与声纳值、声纳值与声导值的均差异有统计学意义（均P〈0.05）;声导纳值与声导值差异无统计学意义（P〉0.05）。1 000 Hz探测音测试,鼓室声导纳值、声纳值与声导值的两两比较均差异有统计学意义（均P〈0.05）。结论：获得正常新生儿多频探测音鼓室声导抗图的图形、声导纳值、声纳值和声导值的正常范围,结果提示,1 000 Hz探测音鼓室声导抗测试可以较好反映正常新生儿的中耳功能。     

Tympanometric changes at 226 Hz and 678 Hz across 10 trials and for two directions of ear canal pressure change

The influence that repeated tympanometric trials have on the aural-acoustic admittance characteristics of the middle-ear transmission system was studied in 24 young adults. The 226-Hz and 678-Hz data were generated by concurrently digitizing the conductance and admittance tympanograms at 25 daPa/s for both ascending and descending pressure directions. Ten successive trials for each frequency and direction of pressure change were made. Changes in admittance corrected for ear canal volume across the 10 tympanometric trials were computed. The results demonstrated that generally admittance increases as the number of trials increases. For many subjects, the complexity of the tympanometric configuration also increases across trials. The results from eight subjects with single-peaked 678-Hz tympanograms were compared with the results from eight subjects with notched 678-Hz tympanograms to explain the mean decrease in susceptance across tympanometric trials. Finally, the pressure peak locations of the conductance, susceptance, and admittance tympanograms were evaluated and are discussed. The effects that differences in peak pressure location have on the computed static admittance values are presented.     

Factors influencing the acoustic-immittance characteristics of the acoustic reflex

Measurements of the aural acoustic-immittance (admittance and impedance) characteristics of the middle-ear transmission system in humans during the quiescent (static) and reflexive states were made (N = 36) utilizing a signal-averaging technique. Three pure tones (750, 1000, and 2000 Hz) and broadband noise stimuli elicited the acoustic reflex in 2-dB steps at sound-pressure levels from 84-116 dB (tones) and 66-116 dB (noise) during ascending- and descending-intensity level runs. The contralateral middle-ear activity was monitored with a 220-Hz probe by digitizing the conductance and susceptance outputs of an admittance meter. A computer corrected for the ear-canal volume utilizing measurements made at ear-canal pressures of 0 and --350 daPa and then converted the conductance and susceptance values into admittance and impedance units. The results were reported in absolute and relative immittance units, including components, as a function of both stimulus sound-pressure level and intensity level above the acoustic-reflex threshold. The static immittance of the middle ear changed nonlinearly over time to lower admittance or higher impedance values. The influence of this static-immittance shift on the reflex magnitude was discussed. The largest mean reflex magnitude and the slowest rate of growth were observed with broadband noise, although eight of the 36 subjects demonstrated the largest reflex magnitude in response to one or more of the tonal stimuli. Although static-immittance values and acoustic-reflex thresholds were poorly correlated, the reflex magnitudes were proportional to static immittance. The variability of the reflex measures was similar to the variability of the static-immittance values. Finally, bi-directional changes in resistance during the reflexive state were observed and discussed.     

Test-retest reliability in tympanometry.

Test-retest reliability for tympanometric measures was evaluated across five sessions in 20 subjects with normal hearing and normal middle-ear function. Tympanograms were obtained on each ear for probe frequencies of 226, 678, and 1000 Hz using both ascending and descending directions of pressure change. Across all conditions, the tympanometric measure that consistently demonstrated the highest test-retest reliability was compensated static acoustic admittance. Test-retest correlations for peak compensated static acoustic admittance measures were higher than those for ambient measures across all probe frequencies and both directions of pressure change; the differences in correlations for peak and ambient measures, however, reached significance only for 226-Hz conditions. Across-session correlations for tympanogram width did not differ significantly for measures referenced to the lowest tympanogram tail and those referenced to +200 daPa.     

Contralateral acoustic reflex thresholds for tonal activators using wideband energy reflectance and admittance.

The purpose of this study was to evaluate a new method for estimating the acoustic reflex threshold incorporating wideband (250-8000 Hz) measures of energy reflectance and admittance (M. P. Feeney & D. H. Keefe, 2001). The wideband technique incorporates both a correlation method to assess the pattern of the reflex-induced shifts in reflectance and admittance across frequency and a magnitude method to determine if the amplitude of the shifts exceeds baseline variability. Contralateral reflex thresholds for 1000- and 2000-Hz activators were obtained for 34 young adults with both the wideband method and a clinical method using a 226 Hz probe tone. Average reflex thresholds obtained with the new method were 12 to 13.7 dB lower than than obtained with the clinical method. When the bandwidth of analysis of admittance and reflectance responses was limited to 250 to 2000 Hz, the reduction in reflex thresholds was accompanied by the rejection of 96% of nonactivator-baseline responses as reflexes. The method holds promise for extending reflex threshold testing to patients with reflexes elevated beyond current equipment limits, for reducing the sound levels used in reflex testing, and for obtaining sensitive measures of reflex threshold in infants.     

Basic principles and clinical applications of tympanometry

This article presents an overview of tympanometric measures using a 226-Hz probe tone, with an additional focus on complex admittance measures at 678 Hz and an introduction to multiple frequency tympanometry. Basic principles underlying all admittance measures are presented. The clinical implementation and interpretation of tympanometry is discussed.     

Choice of probe tone and classification of trace patterns in tympanometry undertaken in early infancy

Tympanometry using 226 Hz, 678 Hz, and 1000 Hz probe tones was undertaken on two groups of babies, age 2 to 21 weeks. A group of 104 babies with normal ABR thresholds or TEOAEs were compared with a second group of 107 babies who had evidence of temporary conductive hearing loss based on the findings of a test battery, which included air and bone conduction ABR. The tympanograms were classified by Method 1, a simple visual classification system, and Method 2, adapted from a system described by Marchant et al (1986). The majority of tympanograms recorded in both groups using the 226 Hz probe tone were 'normal' Type A, with no significant difference in middle ear pressure or static admittance. However, both classification methods demonstrated significant differences between the two groups using the higher frequency probe tones, with Method 2 being the preferred system of classification. Tympanometry using 226 Hz is invalid below 21 weeks and 1000 Hz is the frequency of choice.     

The effect of the 226-Hz probe level on contralateral acoustic stapedius reflex thresholds

PURPOSE: The purpose of this study was to examine the effect of the 226-Hz probe level on the acoustic stapedius reflex threshold. METHOD: Contralateral reflex thresholds for a 1000-Hz pure-tone stimulus were obtained from 40 young adults with normal hearing using an experimental system at four 226-Hz probe levels (70, 75, 80, and 85 dB SPL) with a repeated measures experimental design. RESULTS: A repeated measures analysis of variance revealed that as the probe level increased over this 15-dB range, there was a mean decrease in reflex threshold of 2.5 dB SPL (p < .001), with the largest decrease for an individual participant of 12 dB. CONCLUSION: The results suggest that the level of the 226-Hz probe tone as used in clinical reflex measurements and as specified in the American National Standards Institute (1987) standard is sufficiently high to affect the acoustic reflex by facilitating its activation. The effect is small, on average, but may be of clinical significance for some individuals.     

Wideband reflectance measures of the ipsilateral acoustic stapedius reflex threshold

OBJECTIVE: The purpose of this study was to develop a method for acoustically measuring the ipsilateral acoustic stapedius reflex threshold by using wideband shifts in energy reflectance and admittance. DESIGN: A group of 27 young adult subjects with normal hearing participated in the study. Contralateral reflex thresholds were first measured for a 4000 Hz activator tone (maximum level, 92 dB SPL), using a clinical method with a 226 Hz probe tone. Ipsilateral and contralateral reflex thresholds were then measured by using an experimental wideband reflectance and admittance system that used a band-filtered click (200 to 2000 Hz) as the probe stimulus, presented simultaneously with the 4000 Hz activator tone. Reflex thresholds for the wideband system were determined by using statistical tests of the magnitude of the reflex responses as well as their correlation with other reflex responses. RESULTS: Clinical and experimental reflex thresholds were obtained for 9 of the 27 subjects for all conditions. Clinical reflex thresholds were absent for 8 subjects for whom experimental reflex thresholds were present and were present for 5 subjects who had absent experimental reflex thresholds for one or more conditions. An additional 5 subjects had absent reflex thresholds in all conditions, consistent with the low maximum level of the activator. Wideband measures of contralateral reflex thresholds were approximately 3 dB lower than those obtained with the clinical system. The magnitudes of the group means of the reflex responses were similar for ipsilateral and contralateral stimulations. CONCLUSIONS: Wideband measures of reflectance and admittance may be used to estimate the ipsilateral acoustic stapedius reflex threshold by separating in frequency the spectral energies of the wideband probe stimulus from the activator stimulus. This technique holds promise for measuring reflex thresholds for individuals with absent reflex thresholds through the use of standard clinical methods.     

正常新生儿226Hz及1000Hz探测音鼓室导抗测试

探讨通过瞬态诱发耳声发射(TEOAE)筛查的正常新生儿低频（226Hz）及高频（1000Hz）探测音鼓室导抗图的特点、获得峰声导纳值等指标的正常值范围,为临床新生儿及婴幼儿中耳功能评估和诊断提供依据。方法采用中耳分析仪（GSI-33型）对足月顺产,并通过TEOAE筛查的正常新生儿分别进行低、高频探测音下的鼓室导抗测试,分析鼓室导抗图形态特征并对峰声导纳值等重要数据进行统计。结果在100例首次双耳通过TEOAE筛查的新生儿鼓室导抗测试中,低频鼓室导抗图以双峰型为主（占96%）,高频鼓室导抗图以单峰型为主（占90%）;低频探测音鼓室导抗图为双峰型而其高频探测音鼓室导抗图为单峰型的有174耳（占总耳数87%）;低频及高频探测音鼓室导抗图均为单峰型的仅有6耳（占总耳数3%）。结论正常新生儿低频探测音鼓室导抗图以双峰型为主,高频探测音鼓室导抗图以单峰型为主,应将两者结合来对新生儿及婴幼儿中耳功能进行评估;所获得相应的峰声导纳值、峰声导纳值处外耳道压力、外耳道容积等指标的正常值可以用于初步评估新生儿中耳功能状态。     

Can maximum comfortable loudness levels in hearing impaired listeners be predicted from ipsilateral acoustic reflex thresholds recorded with high frequency probes?

This study was designed to test the effectiveness of the ipsilateral acoustic reflex thresholds measured with low and high frequency probes in predicting the maximum comfortable loudness levels (MaxCLs) in hearing-impaired subjects using recently available sophisticated procedures for acoustic reflex and loudness measures. Loudness growth functions were measured in hearing-impaired subjects at .5, 1 and 2 kHz using a computerized procedure. The maximum level among those sound pressure levels judged as 'comfortable' was designated as the MaxCL. Acoustic reflex thresholds were measured for .5, 1 and 2 kHz activator signals using 226, 678 and 1000 Hz probes. Regression analyses suggested that acoustic reflex thresholds recorded with the 678 and 1000 Hz probes could provide an objective estimate of the MaxCLs for 1 and 2 kHz. Thus, acoustic reflex thresholds may be useful in fitting hearing aids for those subjects in whom reliable measures of MaxCLs cannot be obtained.     

Acoustic-immittance measures in normal ears

A data base of acoustic-immittance measures in normal adults is presented. The subject pool consisted of 127 adults with normal hearing and a negative otologic history. Norms are presented for hearing thresholds, ipsilateral and contralateral acoustic-reflex thresholds, tympanometry, static acoustic-admittance measures, and middle-ear (tympanogram peak) pressure.     

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).     

正常婴儿1000Hz探测音及多频率扫描声导纳测试分析

目的分析正常婴儿1000 Hz探测音及多频率扫描声导纳检测的临床特征。方法对164例正常听力婴儿（250耳）的1000 Hz探测音声导纳图,用基线法分型并测量正峰声导纳值;通过声纳差（ΔB）-频率函数曲线和相位角差（Δθ）-频率函数曲线检测中耳共振频率。运用SPSS11.0软件,分年龄段分别统计正峰声导纳、共振频率和相位角差（Δθ）的平均值、标准差、中位数、5%分位数、95%分位数及95%置信区间。结果全部样本均可测得基线上正峰声导纳值,各年龄组的5%分位数均≥0.2 mmho;各年龄组共振频率从311.01～599.06 Hz递增,相位角差（Δθ）的绝对值平均值从44.52～22.84递减。结论高频率探测音声导纳检测和多频率扫描声导纳检测,充分反映婴儿中耳声学特性的转变过程,更适用婴儿的中耳功能评估。     

Effects of direction and rate of ear-canal pressure changes on tympanometric measures

The effects of the direction (ascending and descending) and rate (12.5, 25.0, and 50.0 daPa/s) of ear-canal pressure changes on three tympanometric measures (peak static admittance, shape, and tympanometric peak pressure) were studied in 24 adults with normal middle-ear transmission systems. Susceptance, conductance, admittance, and phase angle data for the six conditions both at 226 and 678 Hz were obtained using a general purpose computer. Peak static admittance was significantly affected by both the rate and direction of pressure change as evidenced by a decrease in phase angle for ascending and for fast rates of ear-canal pressure change. Tympanometric shape was broader for descending pressure changes with less frequent notching both for descending and for slow rates of pressure change. Finally, the difference in peak pressure for the two directions of pressure change increased with the rate of ear-canal pressure change.