High frequency immittance for neonates: a normative study

CONCLUSION: High frequency immittance measurements demonstrate promise in clarifying middle ear status for neonates but age- and gender-specific norms should be consulted. OBJECTIVE: To describe high frequency immittance measurements using a 1000 Hz probe tone for a sample of 278 neonatal ears (0-4 weeks of age) in order to compile normative tympanometric and acoustic reflex criteria. SUBJECTS AND METHODS: Assessment of neonatal ears included 1000 Hz probe tone immittance measurements (tympanograms and ipsilateral acoustic reflexes), and distortion product oto-acoustic emission (DPOAE) screening. Results were compared and normative values were compiled for immittance measures in ears controlled for normal middle ear functioning (n=250). RESULTS: Comparison of immittance results to OAE screening outcome provides estimates of sensitivity and specificity for middle ear fluid with tympanometry of 57% and 95%, and 57% and 90% for acoustic reflex presence, and 58% and 87% for combined tympanogram and acoustic reflex results, respectively. Normative data indicate that static peak admittance values differ significantly across gender and age with the 5th percentile cut-off value for the entire sample at 1.4 mmho. The 90% range of tympanic peak pressure normative values increases with increasing age from 140 daPa for neonates 1 week of age to 210 daPa for neonates 2-4 weeks of age. Acoustic reflexes were elicited at 93+/-9 dB with a 90% normality range of 80-105 dB.     

听力正常新生儿1000Hz声导抗分析

目的 分析通过耳声发射(OAE)听力筛查正常新生儿1000 Hz声导抗测试的特点,为新生儿听力筛查及新生儿中耳功能的评估提供参考依据.方法 采用GSI-70型自动耳声发射听力筛查仪对新生儿进行听力筛查,将双耳通过OAE听力筛查的正常新生儿按照纳入标准选为研究对象,共650例(1300耳),然后采用GSI TympStar VersionⅡ中耳分析仪对该研究对象进行中耳功能测试,收集探测音为1000 Hz的鼓室导抗图及其相关指标,对图形进行分型并计算各指标的95％医学参考值范围.结果 将纳入的1300耳的鼓室导抗图分类,其中1Y1B1G型732耳(占56.3％)、1Y3B1G型145耳(占11.2％)、0Y0B0G型269耳(占20.7％)、其他154耳(占11.8％).其中声导纳图Y中单峰型有967耳,计算单峰型声导纳图Y各指标的95％医学参考值范围,其中鼓室图峰压(tympanometric peak pressure,Tpp)为- 55.0～180.0 daPa、峰补偿静态声导纳值(peak compensated static acoustic admittance,Peak Ytm)为0.03 ～1.18 mmHo、鼓室图宽度(tympanometric width,TW)为70.0～230.0 daPa.结论 通过OAE听力筛查的正常新生儿1000 Hz探测音的声导纳图Y以单峰型为主.1000 Hz探测音的单峰型声导纳图Y的Tpp、Peak Ytm、TW的95％医学参考值范围可作为新生儿听力筛查及新生儿中耳功能评估时的参考依据.     

豚鼠鼓室导抗图正常值测试及结果分析

目的研究豚鼠鼓室导抗图（tympanogram）各个测试项目的正常值范围及不同性别、耳别之间的差异。方法选取ABR反应阈正常、无耳科疾病的正常豚鼠40只,在麻醉状态下测试其鼓室导抗图,并对不同性别、耳别的各个测试项目的结果进行比较。结果所有鼓室导抗图均符合Jerger分类法中的“A”型曲线,其等效外耳道容积约为0．09±0．02ml,静态声顺值约为0．10±0．03ml,坡度约为0．14±0．06ml,峰压值约为一99．44±75．06daPa。等效外耳道容积在性别间的差异具有统计学意义（P=0．012）,而静态声顺值、坡度和峰压值差异均无统计学意义（P〉0．05）。左右耳间各指标差异均无统计学意义（P〉0．05）。结论雄性与雌性豚鼠鼓室导抗图的等效外耳道容积存在显著性差异,其他各指标的结果在不同性别、耳别之间无明显差异。     

Tympanometric measures of eustachian tube function

The purpose of this study was to develop instructions and procedures and to establish a normal data base for four tympanometric tests of Eustachian tube function: Valsalva, Toynbee, Inflation, and Deflation. Data were obtained for 24 young adults (48 ears) with normal hearing and normal middle-ear function. The tympanograms were analyzed for differences between baseline and experimental (postmaneuver) and baseline and posttest tracings for seven measures: tympanogram peak pressure, peak acoustic admittance, static acoustic admittance, negative gradient, positive gradient, and negative and positive acoustic-admittance values at +/- 400 daPa. The results indicated a statistically significant difference only in peak pressure for baseline and experimental tympanograms. Peak-pressure shifts were most pronounced for the Valsalva and Toynbee procedures. The small pressure shifts characteristic of the Inflation and Deflation procedures coupled with the potential for instrumental error severely limit the use of these procedures as means of obtaining reliable indices of tubal function.     

Static and dynamic acoustic impedance measurements in infant ears.

Tympanometry and acoustic reflex threshold data are reported for a series of presumable normal infants ranging in age from 55 to 132 days. In general, tympanograms displayed single peaks between +/- 50 mm H2O. Susceptance tympanograms with a 660-Hz probe frequency were sometimes characterized by monotonically increasing susceptance as ear canal pressure was changed from -200 to +200 mm H2O. Static values of acoustic conductance, susceptance, admittance, resistance, reactance, impedance, and phase angle were computed from tympanograms using the values of ambient and +200 mm H2O (0/+200 procedure) and maximum and minimum tympanometric values (MAX/MIN procedure). Comparison of the data from the two computational procedures suggested that the MAX/MIN procedure produces means and standard deviations of static values which are more manageable for establishing confidence limits with which to evaluate potentially pathological subjects. The MAX/MIN procedure resulted in lower mean values of conductance and susceptance for infant subjects relative to previously reported adult data using a similar computational procedure. Acoustic reflex thresholds were clearly present in all testable infants at coupler sound pressure levels similar to adult data, suggesting that the relations between reflex thresholds and hearing sensitivity demonstrated in adult subjects are similarly applicable to infant subjects. Mild sedation to induce sleep without altering the reflex would make acoustic reflex threshold measurement a useful procedure for screening large numbers of infants.     

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.     

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.     

Tympanometric norms for Chinese young adults

OBJECTIVE: To obtain tympanometric norms in Southern Chinese young adult population and compare the results with data obtained for a Caucasian population. DESIGN: Ear canal volume (Vea), tympanometric compensated static acoustic admittance (Peak Ytm), tympanometric width (TW) and tympanometric peak pressure (TPP) were obtained on 100 Southern Chinese young adults. Results were compared with findings from Roup et al. (1998). Inter-tester reliability was established. RESULTS: Compared with the results obtained by Roup et al. (1998) on non-Hispanic Caucasian population, Southern Chinese subjects were found to have lower Peak Ytm, wider TW and more positive TPP values. No gender difference was noted for Peak Ytm, TW and TPP values in Chinese subjects. Inter-tester reliability was good. CONCLUSION: The tympanometric norms obtained in this study are recommended when evaluating middle ear function among Southern Chinese young adults.     

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.     

Normative values for tympanometry in 4-5-year-old children

The objective of this study was to determine normative values for tympanometric variables for 4-5-year-old children. Tympanometry was performed at a pre-scheduled visit at the age of 49-68 months on children recruited to a follow-up visit in a vaccine efficacy trial (n=756 children). Tympanograms obtained successfully from healthy ears were analysed. At the time of the visit, mean static acoustical admittance (SAA) was 0.52 cm3, mean tympanometric peak pressure (TPP) was -48 daPa, and mean tympanometric width (TW) was 101. Compared to results obtained for the same study population at 24 months of age, the SAA had increased significantly with age, while the values for TPP and TW had decreased with age. A history of previous tympanostomy tubes increased the admittance of the tympanic membrane by producing atrophic scars. Thus, the tympanograms obtained from ears with previous tubes were considerably higher and narrower (high SAA and low TW). In conclusion, this study further emphasizes the need for age-specific normative values for interpretation of SAA and TW.     

Developmental changes in aural acoustic admittance measurements

Tympanometry is a clinical measurement routinely included in the assessment of middle ear function. Despite its widespread use, however, fundamental questions remain regarding the need for age-dependent normative data. This study examines normal developmental changes associated with four tympanometric measurements: (1) ear canal volume, (2) peak compensated acoustic admittance, (3) tympanometric width, and (4) tympanometric peak pressure. Of 221 infants and children, aged 6 months to 5 years, enrolled in this study, 99 met the criteria for normal middle ear function as determined via pneumatic tympanoscopy by an experienced pediatric otolaryngologist, and data analysis was confined to those 99 volunteers. Analysis of variance revealed statistically significant main effects showing increases in ear canal volume and peak compensated acoustic admittance and decreases in tympanometric width as age increased. Statistically significant differences were not achieved for tympanometric peak pressure. Although statistically significant differences were found, the differences were small and of questionable clinical significance.     

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.     

Impedance audiometry in a young population. The effect of age, sex, and tympanogram abnormalities.

Static compliance, and acoustic reflex thresholds, were studied retrospectively in 883 subjects, aged one to 20 years. Age was a factor in both measurements. In 523 subjects with normal middle ear fuction, static compliance increased as a function of age. Acoustic reflex thresholds for pure tone signals improved with age, while acoustic reflex thresholds for broad band noise (BBN) tended to decrease. Minor tympanogram abnormalities exerted a distinct influence on static compliance and acoustic reflex thresholds. Static compliance was increased, and highly variable, in 93 subjects with A-deep tympanograms. In 212 subjects with either A-deep tympanograms, or slight negative pressure (i.e. -50 to -100 mm H2O), acoustic reflex thresholds were elevated for both pure tone, and BBN signals. In 132 sensorineural impaired subjects, the sensitivity loss differentially affected acoustic reflex thresholds for pure tone vs BBN signals. In view of the potential influence of age, and, especially, minor middle ear abnormalities, on static compliance and acoustic reflex measures, these factors should be seriously considered when interpreting impedance audiometry findings in children.     

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.     

Measuring middle ear admittance in newborns using 1000 Hz tympanometry: a comparison of methodologies

The present study aimed to compare three measures to estimate middle ear admittance in neonates using 1000 Hz tympanometry. Data were obtained from 36 full-term newborns, aged between 24 and 123 hours, who passed a transient evoked otoacoustic emissions test and assessed using a Madsen Otoflex impedance meter. The results showed that the mean middle ear admittances obtained by compensating for the susceptance and conductance components at a pressure of 200 daPa and -400 daPa (Y(CC200) = 1.00 mmho and Y(CC-400) = 1.24 mmho, respectively) were significantly greater than that using the traditional baseline compensation method (Y(BC) = 0.65 mmho). Although Y(CC-400) has attained the highest mean value, it has the lowest test-retest reliability. Hence, the component compensation approach compensated at 200 daPa holds promise as an alternative method for estimating middle ear admittance in neonates. Further research to evaluate its test performance using clinical decision theory is required to determine its clinical significance.     

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.     

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。     

Screening Tympanometry: Criteria for Medical Referral

Tympanograms were obtained from normal preschool and adult subjects with a prototype hand-held tympanometer to obtain normative values for four tympanometric variables: static admittance, equivalent ear canal volume, tympanometric peak pressure, and gradient. Effects of age group, sex, and pump speed (200 or 400 daPa/s) were determined. The results were incorporated into a four-part screening protocol (history, visual inspection, audiometry, and tympanometry) designed to reduce the excessive error rates associated with screening strategies that rely exclusively on tympanometry.     

Screening tympanometry: criteria for medical referral

Tympanograms were obtained from normal preschool and adult subjects with a prototype hand-held tympanometer to obtain normative values for four tympanometric variables: static admittance, equivalent ear canal volume, tympanometric peak pressure, and gradient. Effects of age group, sex, and pump speed (200 or 400 daPa/s) were determined. The results were incorporated into a four-part screening protocol (history, visual inspection, audiometry, and tympanometry) designed to reduce the excessive error rates associated with screening strategies that rely exclusively on tympanometry.     

Changes in rigidity of the internal ear in body tilt

We tried to select information concerning changes in acoustic rigidity of the internal ear in 90% body tilt from tympanogram. In such conditions there is no correlation between a 10-fold rise of perilymph pressure and tympanogram parameters. This contradiction suggests that rigidity of tympanogram is a total of rigidity of the ear canal part, middle and internal ear; that inert rigidity of the middle ear in body tilt masks a weak dynamic component of the internal ear. Determination and isolation of the ear canal rigidity from tympanogram (compensation) is a standard procedure. For compensation of the dominating static component of the middle ear we used an original technique -- deduction of the numbered tympanograms. We estimated that deduction of the initial position tympanogram from subsequent tympanograms yields the dynamic component. The procedure of deduction for the tilt angles +75, 60, 45, 30, 15, O, -15 and -30 produced transformed tympanograms (TT) the rigidity of which was 7-10 times less that peak rigidity of standard tympanograms. Peak rigidity of TT of 5 volunteers (n=8) changed as the function of a tilt angle and significantly differed in different positions. TT rigidity may be formed by peripheral cochlear membranes.