Classification of trace patterns of 226- and 1000-Hz tympanometry in healthy neonates

Objective

Accurate evaluation of middle ear function is a challenge especially in babies referred from newborn hearing screening programs. The aim was to assess the feasibility of tympanometry using 226- and 1000-Hz probe tones in neonates.

Methods

Hearing was evaluated by transient evoked otoacoustic emission (TEOAE) in 96 ears of healthy neonates in well-baby nursery. Babies with risk factors for hearing loss as identified in Joint Committee on Infant Hearing (JCIH, 1994) were excluded. Tympanograms recorded with 226 and 1000 Hz probe tones were analyzed and classified.

Results

Tympanograms were classified according to Method A (Jerger/Liden) and visual classification systems, Method B (adapted from Marchant et al.) and Method C (adapted from Kei et al.), without difficulty. In 72 ears with normal TEOAE, 226 Hz tympanograms were classified as normal in 72 ears in Methods A and B, and 16 ears in Method C. 1000 Hz tympanograms were normal in 68 ears in Method A, 72 ears in Method B and 68 ears in Method C. In 24 ears with abnormal TEOAE, 226 Hz tympanograms were interpreted as normal in most ears (23 ears in Method A, 24 ears in Method B), whereas 1000 Hz tympanograms were abnormal in 13 ears in Method A and 6 ears in Method B, possibly reflecting middle ear dysfunction.

Conclusion

In healthy neonates without risk factors for hearing loss, 1000 Hz tympanograms can be recorded and interpreted. A single-peaked tympanograms was most common in ears with normal TEOAE. In ears with abnormal TEOAE, tympanograms were classified as abnormal more frequently using 1000 Hz than 226 Hz. Implementation of tympanometry using 1000 Hz probe tone in newborn hearing screening programs may provide valuable information regarding middle ear dysfunction that may cause transient conductive hearing loss.     

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。     

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。     

Impedance audiometry with 3-probe frequency]

The 3-probe frequency (226, 678, 1000Hz) admittance (Y), susceptance (B) and conductance (G) tympanograms were recorded from 28 normal-hearing adults with a GSI 33 Version 2 Middle-Ear analyzer, and the 3-frequency ipsilateral acoustic-reflex thresholds were measured too. In all subjects, there were normal values of tympanometric indices, such as peak compliances, peak pressures, gradients and ear canal volumes, and of ipsilateral acoustic-reflex thresholds at a 226-Hz probe tone. From 226 to 1000Hz, Y, B and G increased in magnitude while the corresponding admittance-,susceptance- and conductance-tympanogram peak pressures (PY, PB, PG) shifted towards positive evidently. In comparison with 226 Hz, the 678-Hz static admittance (Y') and static susceptance (B') values were large but had no significant differences as compared with those of 1000 Hz. The relation among Y, B and G, among PY, PB and PG, and between Y' and B' changed as a function of probe frequency from 226 to 1000 Hz. The average reflex thresholds of 25 adults (30 ears) were 83 dB HL at 226-Hz probe frequency, 91 dB at 678 Hz, and 88 dB at 1000 Hz, using a 1000-Hz tonal activator. There were significant differences among the 3 values (all P less than 0.01). The ipsilateral acoustic reflexes from 3 adults (4 ears) were present at 226-and 678-Hz probe tones, but not at 1000 Hz.     

A comparison of tympanometry with 226 Hz and 1000 Hz probe tones in children with Down syndrome

Background

For children with Down syndrome, the incidence of hearing loss may be as high as 78% [1], therefore the American Academy of Pediatrics recommends regular screening for the presence of hearing abnormalities. Tympanometry is used as an indication of middle ear pathology. In our experience, Down's patients’ tympanograms do not always correlate with otoscopic findings. Down's patients have joint laxity, small ear canals, anterior tympanic membrane orientation and softer tissue composition, all factors thought to affect tympanogram results in infants. Because the use of the 1000 Hz tympanometry is widely recognized as standard procedure in the evaluation of infants aged 0–6 months, we propose it may have greater reliability in testing patients with Down syndrome.

Objective

Compare the results of visual inspection of the tympanic membrane by a Pediatric Otolaryngologist to the results of tympanometry at traditional probe tone (226 Hz) and at the infant probe tone (1000 Hz).

Methods

Institutional Review Board – approved prospective study of 26 subject-ears in patients with Down syndrome aged 6 months–18 years but recent stable middle ear/Eustachian tube function using physical examination and tympanometric probe tones at 226 Hz and 1000 Hz.Subject-ears were examined with record of “clear of effusion,” showed the presence of “fluid,” or were to be “excluded.” Blinded to ear exam results, tympanometry was then completed with record of which Jerger classification tympanogram was found at each frequency.

Results

Although the sensitivity of each test was 1, the specificity of the 1000 Hz tympanometry (100%) in this study was markedly improved compared to the specificity of the 226 Hz tympanometry (71%) (p = 0.016).

Conclusions

This pilot study demonstrated evidence that tympanometry in children with Down syndrome may be more reliable at 1000 Hz than at 226 Hz in detecting the presence of middle ear effusion beyond infancy. Use of the 1000 Hz probe tone yielded fewer false positives for disease (type B tympanograms in the setting of absent middle ear disease). Further studies of a larger patient population are needed to corroborate these results.     

1000 Hz声导抗测试豚鼠中耳积液

目的分析用1000Hz探测音测试不同体积中耳内积液情况下的鼓室导抗,评价用高频探测音进行鼓室导抗检测在鼓室积液诊断中的作用。方法使用GSI33中耳分析仪对实验性中耳积液的白色豚鼠进行226Hz和1000Hz探测音的鼓室导抗测试,并对结果进行统计学分析。结果使用Graph Pad Prism 4.0统计软件进行统计学分析,结果显示所有实验组的鼓室峰压值均与对照组有显著性差异,且随着中耳积液量增加,鼓室导抗峰压值有降低的趋势。结论1000Hz探测音的声导抗检查可以反映中耳腔内的积液,鼓室导抗图曲线参数因中耳积液量不同而有差异。     

Tympanometry with 226 and 1000 Hertz tone probes in infants

This study aimed at describing and analyzing tympanometric results obtained with 226Hz and 1000Hz probe tones; checking for correlations between tympanometry, otoacoustic emissions and otoscopic examination; describing abnormal results found in the evaluation procedures.MethodsDouble-blind and prospective study. Our sample included 70 babies, between 7 days and one month and 13 days of age, without risk indicators for hearing loss, evaluated in the State Neonatal Hearing Screening Program. Transient evoked otoacoustic emissions, otoscopic examination and tympanometry with 226Hz and 1000Hz probe tones were used as assessment tools. The study was approved by the Ethics Committee from the institution.ResultsStatistically significant differences were observed (p<0.05) in the tympanometric measures correlation and also between transient evoked otoacoustic emissions and compliance obtained with both probe tones. Most test results were within the normal range (94.28%). Three children (4.28%) were referred to diagnostic follow-up and one (1.42%) had middle ear dysfunction confirmed by otoscopy and 1000Hz tympanometry.Conclusions1000Hz tympanometry is the most reliable probe tone used to evaluate children under three months of age. More studies focusing on middle ear acoustics and mechanics are necessary to provide reliable and precise interpretation in the evaluation of middle ear functions in babies.     

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。     

检测婴儿中耳炎的听力学方法敏感性比较

目的 探讨常规听力学检查中婴儿中耳炎诊断相关的的敏感因素.方法 研究对象为听力筛杳未通过的婴儿48例(96耳),男31例,女17例;年龄1.5～12个月(平均4.3个月).所有受试者均接受了颞骨CT薄层扫描和常规听力学测试.听力学检查包括气导和骨导听性脑干反应(ABR)、40 Hz-听觉相关电位(40 Hz-auditory event related potential,40 Hz-AERP)、畸变产物耳声发射(DPOAE)、声反射及226 Hz、1000 Hz探测音鼓室声导抗.统计软件采用SPSS14.0标准统计软件包.以颞骨CT结果作为诊断的依据,与以下9项因素进行Kappa一致性栓验、单因素X2检验和多因素Logistic回归分析.分析因素包括:226 Hz及1000 Hz探测音鼓室声导抗、ABR气导反应阈值、ABR骨气导反应阈值差值、ABR Ⅰ波潜伏期、ABR Ⅰ～Ⅴ波间期、40 Hz-AERP反应阈值、DPOAE反应幅值及声反射阈值.结果 96耳中,CT确诊中耳炎77耳,中耳正常19耳.以颞骨CT扫描结果作为金标准,Kappa-致性检验表明,1000 Hz鼓室声导抗测试、ABR气导反应阈值、ABR Ⅰ波潜伏期、40 Hz-AERP反应阈值和DPOAE与颞骨CT具有较好一致性(Kappa值均＞0.04,P值均＜0.001).单因素分析提示,有7个因素与婴儿中耳功能有关(P值均＜0.001):1000 Hz探测音鼓室声导抗、声反射阈值、ABR气导反应阈值、ABR气骨导反应阈值差值、ABR Ⅰ波潜伏期、40 Hz-AERP反应阈值和DPOAE.Logistic回归分析显示,1000 Hz探测音鼓室声导抗(P＜0.001)和40 Hz-AERP反应阈值(P=0.004)可以列入Logistic回归方程.结论 1000 Hz鼓室声导抗可作为婴儿中耳炎检出的敏感因素,ABR气导反应阈值、ABR Ⅰ波潜伏期、40 Hz-AERP反应阈值和DPOAE可较好地反映婴儿的中耳功能.     

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).     

不同月龄婴儿声反射与畸变产物耳声发射测试结果分析

目的探讨不同月龄婴儿226 Hz和1000 Hz探测音的中耳声反射测试与畸变产物耳声发射（DPOAE）联合筛查的意义。方法测试对象为来泸州医学院附属医院进行听力筛查或复查的188例（350耳）3天～12月龄的婴儿,分为3天～1月龄组（125耳）,2～3月龄组（89耳）,4～6月龄组（76耳）,7～12月龄组（60耳）,分别进行226、1000Hz探测音声导抗,畸变产物耳声发射测试,对226、1000Hz探测音中耳声反射引出率和DPOAE的通过率进行比较分析。结果3天～1月龄组226、1000Hz探测音声反射引出率和DPOAE的通过率分别为81％、69％、73％;2～3月龄组分别为91％、72％、74％;4～6月龄组分别为90％、83％、79％;7～12月龄组分别为43％、66％、60％。226Hz声反射引出率与DPOAE通过率差异有统计学意义（P〈0．01）,1000Hz声反射引出率与DPOAE通过率差异无统计学意义（P〉0．05）,并且DPOAE筛查结果与1000Hz探测音的声反射结果较一致。结论1000Hz探测音声导抗测试对婴儿中耳功能的诊断价值比226Hz探测音的敏感性更高,与DPOAE协同用于婴儿听力筛查具有良好的临床价值。     

中耳共振频率对鼓室积液的诊断价值

目的:探讨226 Hz静态鼓室图与中耳共振频率诊断鼓室积液的价值,观察两者结合可否提高诊断效能.方法:前瞻性研究对比观察分泌性中耳炎组和对照组,以耳镜检查、纯音测听及GSI-33型中耳分析仪测试结果为标准,将对照组共振频率90%的可信区间(5%～95%)设为正常范围,对分泌性中耳炎组的共振频率进行正常或不正常归类,并对其鼓室图形为B、C型或异型者进行鼓膜穿刺抽液,以抽出液体者为阳性.结果:中耳共振频率在900～1100 Hz之间为正常,分泌性中耳炎组的共振频率明显低于对照组(P＜0.01).B型曲线的抽液阳性率为83%,明显高于C型和异型曲线抽液阳性率(P＜0.05).共振频率正常者,其抽液阳性率为0.≤500 Hz者的鼓室积液阳性率明显高于＞500 Hz者(P＜0.01).结论:通过测试中耳共振频率对判断鼓室是否积液,尤其是对鼓室图形为C型或异型者有重要临床意义.     

Automatic Tympanometry in Clinical Practice

The probe tone of an impedance bridge has a direct effect on the results of tympanometry. The frequency of the probe tone should be close to the resonant frequency of the middle ear. Of three electro-acoustic bridges using three different probe tones, i.e. 800, 625 and 220 Hz, the one using 800 Hz provided the most indentifiable tympanographic pattern incases with ossicular discontinuity. Five different types of tympanograms could be indentified when an 800 Hz tone is used

The stapedius reflex thresholds, on the other hand, show only minor differences with different probe tone frequencies

Important clinical information can be obtained by combining the type of tympanogram with the results of stapedius reflex measurements     

早产极低出生体重儿听性脑干诱发电位特征分析

目的：探讨早产极低出生体重儿（VLBW）听性脑干诱发电位（ABR）的特征,及其与患儿生理特征的关系。方法：选取本院新生儿病区、新生儿重症监护室及听力专科就诊接受检查的早产VLBW儿纳入研究,共59例（118耳）,登记围产期高危因素;选取30例（60耳）同期足月正常出生体重儿作为对照组。对所有患儿进行中耳分析,畸变产物耳声发射和ABR。结果：早产VLBW儿中听力异常的构成比明显大于正常人群,伴有其他高危因素的患儿（42例）阈值高于不伴有其他高危因素者（17例）;相关分析显示,ABR阈值与出生体重、孕周、评估时年龄和调整年龄之间没有相关性（P〉0．05）;ABRI、Ⅲ、Ⅴ波潜伏期和Ⅰ-Ⅲ、Ⅲ-Ⅴ、Ⅰ—Ⅴ波间期等特征参数与患儿评估时年龄和调整年龄呈负相关（P〈0．05）;早产VLBW儿与足月儿在ABR Ⅰ、Ⅴ波潜伏期及Ⅰ-Ⅲ、Ⅲ-Ⅴ波间期等参数间存在差异。结论：早产VLBW儿导致听力损失的根本原因可能并不是胎龄和体重本身,而是与并发症有关;早产VLBW儿中,外周听觉功能异常率高;对于VLBW儿需建立耳声发射与自动ABR两者结合的听力筛查方式并定期随访。     

Wideband reflectance in Down syndrome

ObjectiveChildren with Down syndrome (DS) have a high incidence of middle ear disorders and congenital abnormalities of the external, middle and inner ear. Energy reflectance (ER), a wideband acoustic immittance (WAI) measurement parameter, can measure the sound energy reflected or absorbed in the ear canal over a wider range of frequencies more efficiently and faster than conventional single-tone 226 Hz tympanometry. The aim of the present study was to compare the WAI measurements of children with DS with those of typically developing, normal-hearing children according to their tympanometric findings.MethodsFour groups of children with Down syndrome (age range: 2 years and 4 months to 16 years and 3 months; mean age: 8.5 yr) with normal tympanograms (19 ears), flat tympanograms (13 ears), mild negative pressure tympanograms (6 ears between −100 and −199 daPa at the admittance peak) and severe negative pressure tympanograms (4 ears at −200 daPa or lower at the admittance peak) were assessed. All findings were compared with data obtained from 21 ears of a healthy control group (age range: 3 years and 1 month to 13 years and 11 months; mean age: 7.9 yr). The subjects underwent tympanometry with a 226-Hz probe tone frequency and ER measurements along the 200–6,000 Hz range with a chirp stimulus using the Middle-Ear Power Analyzer (MEPA3 – HearID) by Mimosa Acoustics (Champaign, IL), software, version 3.3 [38].ResultsStatistically significant differences were observed in the ER curves for some comparisons between the studied groups. There was also a negative correlation between the static acoustic admittance at the tympanic membrane level and ER measured with a chirp stimulus at 500 and 1,000 Hz. The discriminant analysis technique, which used a chirp stimulus at 1,000 and 1,600 Hz to classify the participants' data based on ER values, achieved a correct classification rate of 59.52% for participants with DS.ConclusionWhile groups with abnormal middle ear status, as indicated by tympanometry, showed higher ER values compared to the DS tymp A group and the control group, similar reflectance curves were observed between control group and the DS tymp A group. WAI shows promise as a clinical diagnostic tool in investigating the impact of middle ear disorders in DS group. However, further research is required to investigate this issue in narrower age range group and a larger sample size.     

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.     

Auditory brain stem response spectral content in comatose head-injured patients

Auditory brain stem response (ABR) spectral content was analyzed for 25 normal subjects and 70 comatose, severely head-injured subjects. The normal ABR spectrum was characterized by energy peaks in three main regions: 0 to 200 Hz, 500 to 600 Hz and 900 to 1000 Hz. Head-injured subjects, in contrast, showed less overall ABR spectral energy. Even head-injured subjects with normal ABR interwave latency values had reduced spectral energy in comparison to the normal group. Among these subjects, there were differences in spectral content for subjects with good neurologic outcome versus those who died within 2 weeks post injury. Finally, head-injured subjects with abnormal interwave latency intervals typically showed distinctive spectral patterns. This subject group demonstrated energy peaks in frequency regions which, for the other groups, were void of energy peaks. Rationale for further study of ABR spectral content is offered.     

High-frequency (1000 Hz) tympanometry in normal neonates

The characteristics of high frequency (1000 Hz) acoustic admittance results obtained from normal neonates were described in this study. Participants were 170 healthy neonates (96 boys and 74 girls) aged between 1 and 6 days (mean = 3.26 days, SD = 0.92). Transient evoked otoacoustic emissions (TEOAEs), and 226 Hz and 1000 Hz probe tone tympanograms were obtained from the participants using a Madsen Capella OAE/middle ear analyser. The results showed that of the 170 neonates, 34 were not successfully tested in both ears, 14 failed the TEOAE screen in one or both ears, and 122 (70 boys, 52 girls) passed the TEOAE screen in both ears and also maintained an acceptable probe seal during tympanometry. The 1000 Hz tympanometric data for the 122 neonates (244 ears) showed a single-peaked tympanogram in 225 ears (92.2%), a flat-sloping tympanogram in 14 ears (5.7%), a double-peaked tympanogram in 3 ears (1.2%) and other unusual shapes in 2 ears (0.8%). There was a significant ear effect, with right ears showing significantly higher mean peak compensated static admittance and tympanometric width, but lower mean acoustic admittance at +200 daPa and gradient than left ears. No significant gender effects or its interaction with ear were found. The normative tympanometric data derived from this cohort may serve as a guide for detecting middle ear dysfunction in neonates.     

Evaluation of middle ear function in young children: clinical guidelines for the use of 226- and 1,000-Hz tympanometry.

HYPOTHESIS: The aims of the study were to evaluate tympanometry with regard to age and classification system using two probe-tone frequencies and to provide clinical guidelines. METHODS: Six subject groups were included in the evaluation: (1) neonatal intensive care unit babies, (2) children younger than 3 months, (3) children 3 to 6 months old, (4) children 6 to 9 months old, (5) children 9 to 32 months old, and (6) adults. Hearing of all subjects was screened by means of auditory brainstem responses, transient-evoked otoacoustic emissions, or behavioral audiometry. Tympanograms, recorded with probe-tone frequencies of 226 and 1,000 Hz, were classified according to shape and middle ear pressure. Additionally, 1,000-Hz tympanograms were classified based on the Vanhuyse model of tympanometric shapes. Furthermore, tympanometric parameters equivalent ear canal volume, admittance value at +200 daPa, middle ear admittance, tympanometric peak pressure, and tympanometric width were calculated for each tympanogram. RESULTS: For clinical purposes, the visual admittance classification system was more suitable than the Vanhuyse model. Furthermore, in children younger than the age of 3 months, 1,000-Hz tympanometry was easier to interpret and more reliable than 226-Hz tympanometry. From the age of 9 months, 226-Hz tympanometry was more appropriate. In children between 3 and 9 months, the reliability of tympanometry was independent of probe-tone frequency. A two-stage evaluation with a 1,000- to 226-Hz tympanometry sequence was preferred because this reduced the total number of tests. CONCLUSION: The current study provides normative data and age-related guidelines for the use of tympanometry in clinical practice. These results have led to a successful implementation of 1,000-Hz tympanometry in neonatal hearing assessment.