Wideband acoustic immitance – Absorbance measurements in ears after stapes surgery

ObjectivesThe study aimed to thoroughly assess absorbance in ears after stapes surgery (stapedotomy/stapedectomy) and how stapes surgery affects wideband acoustic immittance (WAI) metrics.MethodsEighty-three otosclerotic ears were analyzed pre- and postoperatively. The analysis comprised: air-bone gap (ABG) and WAI which included absorbance measurements, resonance frequency assessment, low frequency tympanometry and metrics derived from these measures.ResultsAbsorbance after stapes surgery changed considerably compared to otosclerotic ears before surgery and also differed from normal ears. Absorbance after stapes surgery revealed two significantly different plot types: single-low-frequency-peak absorbance and two-peaks absorbance. Stapes surgery reduced resonance frequency in majority of operated ears and increased static compliance in low frequency tympanometry. Static compliance difference was directly proportional to ABG improvement at low frequencies. Postoperative ABG at 250 Hz and 500 Hz was most commonly correlated with postoperative WAI parameters. ABG improvement at 3000 Hz and 4000 Hz was directly proportional to absorbance difference at ~3000 Hz and 4000 Hz. It influenced the width of the postoperative absorbance by shifting both sides of the plot (negative values shift the points of the plot toward lower frequencies) with the correlation being more pronounced in postoperative two-peaks absorbance type ears.ConclusionsAbsorbance by itself is not sufficient for assessment of changes to middle function following stapes surgery, and should be complemented with other measures. WAI measurements including absorbance, resonance frequency assessment, low frequency tympanometry, and metrics derived from these measures combined with air-bone gap provide insight into mechano-acoustic changes in the middle-ear system as a result of stapes surgery.     

Wideband acoustic immittance in superior semicircular canal dehiscence

ObjectiveThe apparent effect of superior semicircular canal dehiscence (SSCD) on middle ear- and cochlear impedance has led researchers to investigate the use of wideband acoustic immittance as a screening tool when SSCD is suspected. The purpose of the study was to describe the absorbance characteristics and tympanometric values of ears with confirmed SSCD measured at tympanometric peak pressure (TPP) and at ambient pressure.MethodsWideband Acoustic Immittance was performed at ambient pressure and at TPP on ten participants (12 ears) with confirmed SSCD, as well as on an age- and gender matched control group (12 ears). Inferential statistics were used to determine whether statistical differences existed for the absorbance values at each of the averaged frequencies, the resonance frequency (RF) and tympanometric data between the SSCD and control groups.ResultsThe mean absorbance of the SSCD group reached a maximum at 890.9 Hz and a minimum at 6349.6 Hz. When testing absorbance at TPP, a statistically significant increase/peak in the absorbance values of the SSCD group (compared to those of the control group) was found from 630 to 890.9 Hz and a decrease from 4489.8 to 6349.6 Hz. Similar patterns were observed for absorbance at ambient pressure. A lower mean RF for ears with SSCD as well as an increased mean admittance magnitude (AM) value at RF was found compared to those of the control group.ConclusionThe use of SSCD as a screening tool when SSCD is suspected was strengthened by results similar to those of previous studies. As a result of the significant difference in RF of SSCD ears compared to the RF of the control group, the potential value of measuring the RF of the middle ear to differentiate between mass-and stiffness dominated pathologies, was also illustrated.     

Postoperative change in wideband absorbance after tympanoplasty in chronic suppurative otitis media

ObjectiveTo identify the wideband absorbance (WBA) of reconstructed TM comparing with perforated and normal TM, and to investigate the efficacy of WBA to predict postoperative hearing outcome.MethodsNinety-eight adults (128 ears) with normal TM and 40 patients (40 ears) who were diagnosed with chronic suppurative otitis media (CSOM) and underwent tympanoplasty type 1 were enrolled. Pure tone audiometry and WBA were measured before and 6 and 12 months after surgery. Finally, only 29 patients in CSOM group completed all the tests.ResultsSignificant differences in WBA were observed between normal ears, CSOM, and reconstructed ears at middle to high frequencies. During follow-up, absorbance decreased at low frequencies and increased at middle to high. Significant positive correlation at low to middle frequency was observed between change in air-bone gaps (ABG) and absorbance at corresponding frequencies.ConclusionWBA in patients with CSOM was significantly different from normal TM, and a significant change in WBA was observed after tympanoplasty with improvement of ABG. WBA may be a useful tool for monitoring the postoperative change in absorbance of sound energy in the middle ear.     

耳硬化症和中耳畸形患者的宽频声导抗研究

目的探讨宽频声导抗测试对耳硬化症和中耳畸形辅助诊断中的应用价值。方法收集耳硬化症组45耳,先天性中耳畸形组13耳,另有正常组76耳作为对照,所有受试者均行宽频声导抗测试,对各组峰压下的声能吸收率进行分析比较。结果峰压下,耳硬化症组的声能吸收率在917/972~1029/1091~1297/1456/1731/2059~3462/4000~5339Hz比正常组的显著减小(P<0.05)。耳硬化症患者在1kHz以下较正常组无异常切迹。峰压下,先天性中耳畸形组的声能吸收率在408~749/7336~7772Hz比正常组的显著增大(P<0.05),在1059~1224/1297/1414~1456/4000~4490Hz比正常组的显著减小(P<0.05)。69%(9/13)的先天性中耳畸形患者在1kHz以下有一切迹。结论声能吸收率鼓室图在1kHz以下出现切迹提示患者存在镫骨畸形合并锤骨和/或砧骨畸形。仅镫骨固定患者1kHz以下无切迹。宽频声导抗对于术前评估耳硬化症和中耳畸形患者中耳听骨链情况具有现实意义,可作为辅助耳硬化症和中耳畸形诊断的听力学检查之一。     

Differentiating among conductive hearing loss conditions with wideband tympanometry

Objective

This study was aimed to investigate whether wideband tympanometry (WBT) can distinguish among various kinds of conductive hearing loss and provide additional information.

Analysis of wideband tympanometry in Ménière’s disease

IntroductionEndolymphatic hydrops is the pathophysiological substrate of Ménière’s disease. The changes in the inner ear, transmitted to the middle ear through changes in the ossicular chain mobility, can be quantified by wideband tympanometry, through the measurement of the acoustic absorbance at multiple frequencies, represented by the sound energy absorbed by the middle ear, even at its early stages. Studying the behavior of the middle ear through the absorbance in patients with endolymphatic hydrops under ambient pressure and under peak pressure can be useful for detecting Ménière's disease.ObjectiveTo characterize acoustic absorbance behavior in subjects with symptomatic and asymptomatic Ménière's disease compared to controls, in order to verify the ability of wideband tympanometry to detect Ménière's disease.MethodsWe carried out a cross-sectional study with a diagnostic approach comparing the findings of wideband tympanometry at ambient pressure and peak pressure between the ears of the control group (n = 30), the asymptomatic group (n = 21) and the symptomatic group (n = 9).ResultsDifferent peak pressure values were found between the ears of the control group (0 daPa), the asymptomatic group (?11 daPa) and the symptomatic group (?192 daPa), with p < 0.05 by the Kruskal-Wallis test, Mann Whitney test and Bonferroni correction. Different absorbance values were found between the ears of the symptomatic group and the asymptomatic group compared to the control group for low frequencies at ambient pressure and peak pressure, with p < 0.05 by the Kruskal-Wallis test, Mann Whitney test and Bonferroni correction.ConclusionsThe Wideband Tympanometry test was capable of identifying the presence of Ménière´s disease, and to differentiate between asymptomatic and symptomatic patients, when comparing them with healthy individuals.     

Preoperative evaluation of ossicular chain abnormality in patients with conductive deafness without perforation of the tympanic membrane

OBJECTIVE: To evaluate the usefulness of pure-tone audiometry, tympanometry, and liquid and acoustic reflex (AR) tests in the differential diagnosis of ossicular fixation and discontinuity. DESIGN: A prospective clinical trial. SETTING: Tertiary referral center. PATIENTS: Thirty-nine patients (46 ears) undergoing operations at University of Tsukuba Hospital, Tsukuba, Japan, from 1990 through 2003 for conductive deafness without perforation of the tympanic membrane. Clinical examinations for the preoperative diagnosis included pure-tone audiometry, tympanometry, and liquid and AR tests. We compared the preoperative diagnosis with the surgical findings. RESULTS: Although neither pure-tone audiometry nor tympanometry contributed to the differential diagnosis of ossicular chain abnormality, liquid and AR test results showed a significant difference between fixation and discontinuity of the ossicular chain. With the liquid test, bone conduction at lower frequencies was improved by filling the external auditory canal with water at lower frequencies in cases of ossicular fixation. In contrast to the findings observed in ossicular fixation, no improvement of the threshold of bone conduction was recognized at any frequency in the ears with ossicular discontinuity. In ipsilaterally stimulated AR, the reversed pattern was the most marked at 2000 and 500 Hz in ossicular fixation and discontinuity, respectively. CONCLUSION: Liquid and AR tests are reliable examinations for the differential diagnosis of ossicular fixation and discontinuity.     

Wideband energy reflectance measurements in adults with middle-ear disorders.

The purpose of this study was to examine wideband energy reflectance (ER) at ambient pressure in adults with a variety of middle-ear disorders. The ER results from 9 participants with middle-ear disorders and 1 participant with bilateral sensorineural hearing loss were compared with data provided by a group of 40 young adults with normal hearing sensitivity. Wideband ER results for the participant with sensorineural hearing loss followed the typical pattern of the data for young adults with normal hearing. For the 9 participants with middle-ear disorders (13 ears), the wideband ER responses fell outside the 5th to 95th percentile of the normative data for some portion of the frequency range in patterns that were distinct for otitis media with effusion, otosclerosis, ossicular discontinuity, and perforation of the tympanic membrane. Two ears with hypermobile 226-Hz tympanograms and normal hearing sensitivity had low-frequency ER patterns similar to that of a patient with ossicular discontinuity. One participant with negative middle-ear pressure had high ER in the low frequencies. This distinct ER pattern was similar to the patterns produced by participants with otosclerosis, demonstrating that a correction for middle ear pressure will be important for the clinical application of ER. Overall, the results suggest that wideband ER may be useful as a diagnostic tool in the assessment of middle-ear disorders.     

中耳功能正常与异常婴儿的宽频声导抗能量吸收率特性研究

目的：对比中耳功能正常与异常婴儿宽频声导抗（wideband acoustic immittance ，WAI）能量吸收率（wideband absorbance ，WBA）的差异，探讨宽频声导抗对婴儿中耳功能诊断的作用。方法根据高频（1 kHz）声导抗（high frequency tympanometry ，HFT ）、畸变产物耳声发射（DPOAE）及听性脑干反应（ABR）结果将3～12月龄婴儿46例分为中耳功能正常组31例（50耳）和中耳异常组15例（20耳），用96 dB peSPL 的宽频短声（频率范围226～8000 Hz）对两组进行宽频声导抗测试，比较两组能量吸收率特性，分析中耳功能对不同频率能量吸收率的影响。结果无论外耳道压力为峰压还是0 daPa时，除8000 Hz外，中耳功能正常组婴儿的宽频声导抗能量吸收率均高于中耳功能异常组，且2000 Hz处两者差异最大。当外耳道压力为峰压时，中耳功能正常组与异常组226～6727 Hz WBA差异均有统计学意义（P＜0．05）；当外耳道压力为0 daPa时，中耳功能正常组与异常组500～6727 Hz WBA差异有统计学意义（P＜0．05）。结论中耳功能正常与异常婴儿宽频声导抗能量吸收率差异有统计学意义，宽频声导抗可作为有效检测婴儿中耳功能的方法之一。     

Comparison of real-ear insertion gains in Japanese-speaking individuals wearing hearing aids with DSLv5 and NAL-NL2

ObjectiveWe used real-ear insertion gain (REIG), with the international speech test signal (ISTS), to evaluate the amplifying characteristics of hearing aids, set for patients who have been wearing such aids for a long time in a stable manner. We further compared this to the target values of the DSLv5 and NAL-NL2 methods.MethodsThe subjects were adults with moderate sensorineural hearing loss. We examined 40 ears in 25 individuals (15 people wearing hearing aids in both ears and ten people wearing aid in only one ear). Fit assessments were performed based on the speech performance-intensity functions and tolerance of environmental noise, and the ears studied were categorized as either ears with sufficient benefit or ears with insufficient benefit. Additionally, we evaluated the REIG for international speech test signals at 65-dB and 80-dB sound pressure level (SPL). We compared the REIG and target values for voice input at 65-dB and 80-dB SPL, calculated from the DSLv5 and NAL-NL2 methods.ResultsAmong the 40 ears, 34 received sufficient benefit and six received an insufficient benefit from hearing aids. The REIG for ISTS at 65-dB in the sufficient benefit ears, at frequencies of 1,000 Hz and 2,000 Hz, were similar to the target values of NAL-NL2 and DSLv5 but were significantly lower at 250 Hz, 500 Hz, and 4,000 Hz frequencies. The compression ratio of REIG for sufficient benefit ears was similar to that of DSLv5. The REIG for ISTS at 65-dB in the insufficient benefit ears was smaller than that in the sufficient benefit ears at frequencies of 2,000 Hz and 4,000 Hz.ConclusionThis study suggested that the target values of NAL-NL2 and DSLv5 are appropriate, even for Japanese-speaking individuals, at mid-pitch sounds. Although it is necessary to investigate the necessity for low-pitch and high-pitch gains further in the future, this study provides meaningful data regarding the amplifying characteristics in Japanese-speaking individuals who have been wearing hearing aids in a stable manner.     

Audiological results of endoscopic surgical repair of the long process of incus

ObjectiveThe purpose of this study is to evaluate our experience with endoscopic repair of ossicular discontinuity at the incudostapedial joint, with or without an intact stapes suprastructure, and present our hearing results. We classify results based on the causative pathology, the type of ossiculoplasty, and type of lesion. We demonstrate the ability to endoscopically place a total ossicular replacement prosthesis (TORP), measuring 4.25 mm, between the stapes footplate and the incus remnant to reestablish ossicular continuity.MethodsThis was a retrospective case series conducted in tertiary referral center (Hopital de la Timone) Marseille, France. 25 patients underwent incudostapedial rebridging ossiculoplasty between 2009 and 2013. Fifteen cases of chronic otitis media and 10 otosclerosis revisions were included in the study. Three different materials were used in ossiculoplasty, hydroxyapatite cement, incus remnant, and partial/total ossicular replacement prostheses. Audiometric results were evaluated before and after ossiculoplasty. Twelve month follow-up data is provided.ResultsThe mean postoperative air-bone gap was 15 dB (5–25 dB). Hearing results were better inotosclerosis revisions. Hydroxyapatite cement produced an air-bone gap of 5 dB, TORP placed under the incus produced a 12 dB gap, and TORP placed under the malleus resulted in a 12 dB gap and one deaf ear. In cases of chronic otitis media, the residual air-bone gap was 17 dB with PORP, 12 dB with TORP, and 20 dB with incus transposition.ConclusionThe hydroxyapatite cement is effective in the reconstruction of ossicular discontinuity but the high price limits its utilization. TORP placed under the incus is a reliable and stable method of ossicular reconstruction that is cost effective and offers satisfactory hearing results in selected patients.     

Distinguishing healthy from otosclerotic ears: effect of probe-tone frequency on static immittance

The diagnostic utility of static immittance (SI) with respect to distinguishing healthy from otosclerotic ears was investigated at different probe-tone frequencies in 68 healthy ears and 36 ears with surgically confirmed otosclerosis. Because one effect of otosclerosis is to shift the resonant frequency of the middle ear to higher values as a result of increased stiffness of the middle ear system, it was hypothesized that SI measured at higher probe-tone frequencies may provide a better distinction between healthy and otosclerotic ears. As expected, the results of this study indicate that SI measured at higher probe-tone frequencies is superior to a standard low probe tone in the detection of otosclerotic ears. Through systematic and objective comparisons of relevant probetone frequencies using both group statistics and test performance analysis, the present study suggests 630 Hz as an optimum probe-tone frequency for measuring SI with respect to distinguishing healthy ears from otosclerotic ears.     

Does bilateral otosclerosis make pre-operative bone conduction more inaccurate?

Objectives:To assess whether bilateral otosclerosis renders pre-operative bone conduction more inaccurate by increasing the Carhart effect.Methods:Retrospective review of a database of pre and post-operative audiograms of 745 ears with otosclerosis treated with stapedectomy from 2013 to 2020 in a tertiary centre.Main outcome measures:Change in bone conduction after stapedectomy for otosclerosis in:unilateral otosclerosis(U1);bilateral otosclerosis undergoing first side surgery(B1);bilateral otosclerosis undergoing second side surgery(B2).The magnitude of change in bone conduction post-operatively within and between each group.Results:The average difference in pre and post-operative bone conduction was significant within in all groups(T-stat>2 and P-value<0.05)with the greatest change observed in the U1 group.Analysis of average change in bone conduction between groups did not reach statistical significance(Pvalue=0.37).Analysis of change per frequency demonstrated the greatest change in bone conduction post-operatively at 2000 Hz in all groups.The magnitude of change at 2000 Hz was the greatest in the bilateral groups;however,it did not reach statistical significance when compared to the unilateral group(P-value=0.36).Conclusions:This is the first study in the literature to assess the accuracy of pre-operative bone conduction in bilateral versus unilateral otosclerosis.There is no evidence that pre-operative bone conduction in bilateral otosclerosis is more inaccurate than in unilateral disease.In order to assess accuracy of pre-operative bone conduction in otosclerosis a reliable method of assessing post-operative bone conduction is required,without assumption of its equivalence to cochlear reserve.     

Die komplexe Trommelfellimpedanz bei verschiedenen Mittelohrhörschäden

Summary Clinical experience with two-component registration (susceptance and conductance) of the tympanic membrane impedance at two frequencies (220 and 660 Hz) is reported. More than 1000 results of the last 6 years have been evaluated. The normal tympanometric shape is confirmed by computer simulation.More information about mass and elasticitiy relations of the middle ear is obtained by the complex registration at 660 Hz. Clinical examples are presented to demonstrate the influence of scars on the ear drum and of a disruption of the ossicular chain. In 80 cases of otosclerosis with stapes fixation, as confirmed by operation, the shape of the pressure-dependent admittance is significantly narrower than in normal hearing ears. For a glomus tumor a pulsation of the otoadmittance following the electro-cardiogram can be shown.In a classification of the tympanometric types the different shapes correspond well to the set of functional finding (normal ears, otosclerosis, Eustachian tube malfunction, processes of the middle ear cavity, post operation state). The extreme sensitivity of the method, however, produces a small group of unpredictable results for each type. So differential diagnosis is to be done by usual audiometric methods or microscopy of the ear drum.     

Clustering upper airway physicals,otitis media with effusion and auditory functions in children

ObjectiveAdenoid hypertrophy (AH) has been identified as a cause of otitis media with effusion (OME), which is the most common cause of childhood hearing loss. Indeed, there may be other upper airway-related predisposing factors such as, location of the adenoid, accompanying tonsillar hypertrophy (TH) and nasal septal deviation (NSD) for the development of OME. In this study, we aimed to evaluate the associations between the upper airway physicals and OME with auditory functions.MethodsEighty-six ears of 43 children, aged 3–11 years were included in this prospective clinical study. Findings of otolaryngologic examinations were noted. Data of pure tone audiometry (PTA), traditional tympanometry (TT) and wideband tympanometry (WBT) parameters were collected. Cluster analysis was performed to the following variables: age, sex; the adenoid choana percentage (ACP), the presences of adenoid around torus tubarius (AATT), TH, NSD and OME; peak pressure (PP) values on TT, resonance frequencies (RF) on WBT, ambient pressure absorbance ratios (APAR) and PTA hearing thresholds.ResultsTwo groups of ears revealed by clustering; cluster-1 (n = 46) and cluster-2 (n = 40), at the similarity level of 0.662. The presences of AH, AATT, OME and the medians of ACP, PP, RF, WBT APARs at all frequencies except 5656 Hz and 8000 Hz, all PTA thresholds were significantly different between two clusters (p < 0.05). The lower WBT APARs and higher PTA thresholds were associated with higher levels of ACP and higher frequencies of the presence of AATT and OME in cluster-1.ConclusionThere are associations between AH, AATT and OME together with decline in hearing and SEA. Whereas, TH and NSD are not related to the formation of clusters and they are insignificant factors.     

Finite element analysis of auditory characteristics in patients with middle ear diseases

Conclusion: This study validates that a finite element model of the human ossicular chain and tympanic membrane can be used as an effective surgical assessment tool in clinics.

Objective: The present study was performed to investigate the application of a finite element model of ossicular chain and tympanic membrane for fabrication of individualized artificial ossicles.

Methods: Twenty patients (20 ears) who underwent surgery for middle ear disease (n?=?20) and 10 healthy controls (10 ears) were enrolled in the hospital. Computed tomography (CT) and pure tone audiometry were performed before and after surgery. A finite element model was developed using CT scans, and correlation analysis was conducted between stapes displacement and surgical methods. An audiometric test was also performed for 14 patients before and after surgery.

Results: Stapes displacement in the healthy group (average?=?3.31?×?10^?5?mm) was significantly greater than that in the impaired group (average?=?1.41?×?10^?6 mm) prior to surgery. After surgery, the average displacement in the impaired group was 2.55?×?10^?6 mm, which represented a significant improvement. For the patients who underwent the audiometric test, 10 improved hearing after surgery, and stapes displacement increased in nine of these 10 patients.     

Effects of ear canal static pressure on the dynamic behaviour of outer and middle ear in newborns

ObjectiveThe present study investigated the effect of ear canal pressure on the dynamic behaviour of the outer and middle ear in newborns with and without a conductive condition using the sweep frequency impedance (SFI) technology.MethodsA test battery consisting of automated auditory brainstem response (AABR), transient evoked otoacoustic emission (TEOAE) and 1000-Hz tympanometry (HFT) was performed on 122 ears of 86 healthy newborns and 10 ears of 10 newborns with a conductive condition (failed TEOAE and HFT). The dynamic behaviour of the outer and middle ear, when the pressure applied to the ear canal was varied from 200 to −200 daPa, was evaluated in terms of the sound pressure level (SPL) in the ear canal, resonance frequency (RF) and displacement (ΔSPL).ResultsApplication of either a positive or negative static pressure to the ear canal of healthy newborns increased the resonance frequency of the outer (RF1) and middle ear (RF2), but decreased the displacements of the outer (ΔSPL1) and middle ear (ΔSPL2). Positive static pressures resulted in lower SPL while negative static pressures resulted in higher SPL than that at ambient pressure (0 daPa). At −200 daPa, more than 90% of ears showed signs of collapsed ear canal. The dynamic behaviour under various positive and negative static pressures for newborn ears with a conductive condition indicated similar pattern of SPL, RF1 and ΔSPL1 responses for the outer ear as per healthy ears, but abnormal responses for the middle ear.ConclusionsWhile both positive and negative pressures applied to the ear canal have the same effect of stiffening the outer and middle ear, negative pressure of up to −200 daPa resulted in more than 90% of ears with a collapsed ear canal. The results of the present study do not only offer useful clinical information for differentiating healthy ears from ears with a conductive condition, but also provide information on the maturation aspects of the outer and middle ear in newborns.     

Effects of endolymphatic hydrops on acoustic energy absorbance

Abstract

Background: The presence of endolymphatic hydrops (EH) may cause hearing loss and affect the transmission of acoustic energy to the inner ear.

Objectives: Acoustic energy absorbance on wideband acoustic immittance (WAI) was evaluated, focusing especially on EH in the vestibule.

Material and methods: A total of 32 ears from 16 patients who underwent 3-T magnetic resonance imaging (MRI) to evaluate the presence of EH were examined, retrospectively. The degree of EH in the vestibule was classified into three grades (no, mild, and significant), and pure tone audiometry (PTA) and WAI were measured before and after a glycerol drip.

Results: Ears with significant EH showed significantly higher hearing levels and air-bone gaps (ABG), and higher absorbance values on WAI at low frequencies (560–600?Hz) than ears with mild or no EH. Changes in absorbance values were observed in some ears without threshold change on PTA.

Conclusions and Significance: This study showed significantly higher absorbance values of acoustic energy with significant vestibular EH at low frequencies. Considering ABGs observed in ears with significant EH, the presence of EH in the vestibule might cause an obstacle to the transmission of acoustic energy to the inner ear.     

宽频声导抗应用于评估0-24月龄婴幼儿中耳功能检查的临床研究

目的 建立正常0-2周岁中国婴幼儿宽频声导抗(wideband tympanometry,WBT)吸收率的参考值范围.对比正常耳和分泌性中耳炎患儿宽频声导抗的鼓室图结果以及宽频能量吸收率(wideband absorbance,WBA)的差异,探讨宽频声导抗对婴幼儿中耳功能诊断的意义.方法 入选者中耳功能正常155例(...     

Effect of ear canal pressure and age on wideband absorbance in young infants

Objective: The study investigated the effect of ear canal pressure and age on wideband absorbance (WBA) in healthy young infants.

Design: Using a cross-sectional design, WBA at 0.25 to 8?kHz was obtained from infants as the ear canal pressure was swept from?+200 to ?300 daPa. Study sample: The participants included 29 newborns, 9 infants each at 1 and 4 months and 11 infants at 6 months of age who passed distortion product otoacoustic emissions test. Results: In general, negative-ear canal pressures reduced WBA across the frequency range, while positive-ear canal pressures resulted in reduced WBA from 0.25 to 2?kHz and above 4?kHz with an increase in absorbance between 2 and 3?kHz compared to WBA at ambient pressure. The variation in WBA below 0.5?kHz, as the pressure was varied, was the greatest in newborns. But, the variation was progressively reduced in older infants up to the age of 6 months, suggesting stiffening of the ear canal with age. Conclusions: Significant changes in WBA were observed as a function of pressure and age. In particular, developmental effects on WBA were evident during the first six months of life.