Pediatric Applications of Wideband Acoustic Immittance Measures

Wideband Tympanometry and Pressurized Otoacoustic Emissions in Children with Surgical Excision of Palatine and/or Pharyngeal Tonsils

Palatine and pharyngeal tonsil hypertrophy may lead to dysfunction of the auditory tube due to a propensity for infection, potentially giving rise to otitis media. This is a quantitative and longitudinal study, developed from 2019 to 2021, at the State University of Campinas (UNICAMP). The studied sample comprised 15 participants aged 5 to 12 years (mean 7.9 years), 12 male and 3 female, arranged into two groups: children diagnosed with pharyngeal and/or palatine tonsil hypertrophy who were candidates for surgery (G1), and children who were later evaluated after surgery (G2). As part of the test, an otoscopy and measurements of logoaudiometry, pure-tone threshold audiometry, wideband tympanometry (ambient and peak pressure), and otoacoustic emissions (TEOAEs and DPOAEs, both at ambient and peak pressure) were all performed. There were statistically significant differences between phases in pure-tone audiometry, in terms of 226 Hz tympanometry, wideband tympanometry in peak pressure conditions, in the amplitude measurement TEOAEs in both pressure conditions, in DPOAEs in ambient pressure conditions, and in the signal/noise measurement in both pressures in DPOAEs. Overall, it was found that hearing tests were different for subjects with palatine and pharyngeal tonsil hypertrophy compared to the post-surgical group.

Survey of Wideband Acoustic Immittance Use by Clinical Audiologists

PURPOSE

Wideband acoustic immittance (WAI) is a promising measure of middle-ear mechanics. In contrast to standard tympanometry, which is generally measured at a single stiffness-dominated low frequency, WAI detects mechanical effects on both the mass and stiffness properties of the middle ear across a wide range of frequencies, resulting in a more comprehensive assessment of middle-ear mechanics in healthy and pathological ears. Despite a plethora of research demonstrating the clinical utility of this measure, clinical adoption of WAI is still limited. This work explores audiologists' use and perceptions of WAI, with the goal of identifying the barriers to its clinical adoption.

METHOD

A survey on the perception and use of WAI by clinical audiologists in the United States was developed and administered using the Research Electronic Data Capture application. The survey was distributed broadly across the United States. Participation was voluntary and anonymous, and no compensation was provided.

RESULTS

Findings from 132 survey respondents across 32 states were included in the analyses. Overall, findings suggest the largest barriers to clinical adoption of WAI are lack of access to equipment that measures WAI and lack of training and/or confidence in measuring or interpreting WAI.

CONCLUSIONS

Several barriers to clinical adoption of WAI were identified. However, findings also provide optimism in that audiologists utilizing WAI find it more useful than standard tympanometry, and most audiologists who do not currently use WAI are open to implementing the measure in their clinical practice. We proposed steps to address the highest priority issues and increase the clinical viability of WAI.

Predicting wideband real-ear-to-coupler differences in children using wideband acoustic immittance

Individual differences in ear-canal acoustics introduce variability into hearing aid output that can affect speech audibility. Measuring ear-canal acoustics in young children can be challenging, and relying on normative real-ear-to-coupler difference (RECD) transforms can lead to large fitting errors. Acoustic immittance measures characterize the impedance of the ear and are more easily measured than RECD. Using 226 Hz tympanometry to predict the RECD is more accurate than using age-based average RECD values. The current study sought to determine whether wideband acoustic immittance measurements could improve predictions of wideband real-ear-to-coupler difference (wRECD). 150 children ages 2-10 years with intact tympanic membranes underwent wRECD and wideband acoustic immittance measures in each ear. Three models were constructed to predict each child's measured wRECD: the age-based average wRECD, 226 Hz admittance wRECD, and wideband absorbance wRECD. The average age-based wRECD model predicted the child's measured wRECD within 3 dB in 62% of cases, but both the 226 Hz admittance and wideband absorbance wRECD were within 3 dB in 90% of cases. Using individual 226 Hz or wideband absorbance to predict wRECD improved the accuracy and precision of transforms used for pediatric hearing aid fitting.

Characteristics of large vestibular aqueduct syndrome in wideband acoustic immittance

Objective

To describe the characteristics of large vestibular aqueduct syndrome (LVAS) in wideband acoustic immittance (WAI) and to explore whether inner ear deformity has an impact on WAI results.

Methods

Subjects with typical LVAS (LVAS group) and control subjects with a normal anatomical structure of the inner ear (control group) were screened from pediatric patients with cochlear implants using thin-slice computed tomography (CT) images of the temporal bone. With inflammation of the auditory canal and middle ear excluded by routine ear examination and 226 Hz acoustic immittance, WAI data were acquired. Then, the maximum absorbance as the major observation indicator on the mean tympanogram was compared between the LVAS group and control group, and a descriptive comparison of the mean tympanogram and frequency-absorbance curve at peak pressure was performed between the two groups.

Results

The LVAS group included 21 cases (38 ears), and the control group included 27 cases (45 ears). All LVAS subjects met the Valvassori criteria, and the VA at the horizontal semicircular canal displayed flared expansion. On the mean tympanogram, the maximum absorbance in the LVAS group (0.542 ± 0.087) was significantly higher than that in the control group (0.455 ± 0.087) (p < 0.001). The tympanogram in the LVAS group showed an overall elevation, and the absorbance at all pressure sampling points was significantly higher than that in the control group (p < 0.001). The frequency-absorbance curve at peak pressure first increased and then decreased in both groups, and the LVAS group showed higher absorbance than the control group in the frequency range below 2,828 Hz. The absorbance at 343-1,124 Hz was significantly different between the two groups (p < 0.001), and 343-1,124 Hz was the major frequency range at which the maximum absorbance on the mean tympanogram increased in the LVAS group.

Conclusion

Large vestibular aqueduct syndrome (LVAS) shows increased absorbance in low and medium frequency ranges in WAI. The maximum absorbance on the mean tympanogram can serve as a reliable evaluation indicator. Inner ear factors must be considered when middle ear lesions are analyzed by WAI.

Wideband Acoustic Immittance in Children

As wideband absorbance (WBA) gains popularity, it is essential to understand the impact of different middle ear pathologies on the absorbance patterns as a function of frequency in children with various middle ear pathologies. More recently, the use of wideband tympanometry has enabled clinicians to conduct WBA at ambient pressure (WBA _amb ) as well as the pressurized mode (WBA _TPP ). This article reviews evidence for the ability of WBA measurements to accurately characterize the normal middle ear function across a wide range of frequencies and to aid in differential diagnosis of common middle ear disorders in children. Absorbance results in cases of otitis media with effusion, negative middle ear pressure, Eustachian tube malfunction, middle ear tumors, and pressure equalization tubes will be compared to age-appropriate normative data. Where applicable, WBA _amb as well as WBA _TPP will be reviewed in these conditions. The main objectives of this article are to identify, assess, and interpret WBA _amb and WBA _TPP outcomes from various middle ear conditions in children between the ages of 3 and 12 years.

Can Wideband Tympanometry Predict the Prognosis of Otitis Media With Effusion?

Background and Objectives

This study aims to evaluate the capacity of wideband tympanometry (WBT) in predicting the prognosis of otitis media with effusion (OME).

Subjects and Methods

Sixty-one ears with effusion and 30 healthy ears of children were enrolled. The patients were followed up monthly using WBT. After the completion of measurements, the ears were separated into four groups according to the duration of recovery; Group 1: Good prognosis (≤1-month, n=18), Group 2: Worse prognosis (>1-month, n=29), Group 3: Surgical (no recovery, n=14), and Group 4: Control (healthy ears, n=30). Tympanometric peak pressure (TPP), resonance frequency (RF), and absorbance levels were compared within and between the groups.

Results

The TPP and RF values of the study group were lower than those of the controls (p<0.001). The ears with OME had lower absorbance measures than the controls at all frequencies; the differences were significant at 250, 500, and 1,000 Hz (p<0.001). However, at 2,000 Hz, the absorbance levels of the ears with OME were similar with those of the control group only in the good prognosis group (p>0.05). The receiver-operating characteristic analysis revealed that absorbance measures over 0.237 and 0.311 at 1,000 Hz and 2,000 Hz, respectively, have sensitivities and specificities over 70% for prediction of good prognosis, and the calculated odd ratio for these measures were 6 (p<0.05).

Conclusions

WBT measurement is promising in predicting the recovery of OME in children.

Wideband Acoustic Immittance in Cochlear Implant Recipients: Reflectance and Stapedial Reflexes

OBJECTIVES

to characterize differences in wideband power reflectance for ears with and without cochlear implants (CIs), to describe electrically evoked stapedial reflex (eSR)-induced changes in reflectance, and to evaluate the benefit of a broadband probe for reflex threshold determination for CI recipients. It was hypothesized that reflectance patterns in ears with CIs would be consistent with increased middle ear stiffness and that reflex thresholds measured with a broadband probe would be lower compared with thresholds obtained with a single-frequency probe.

DESIGN

Eleven CI recipients participated in both wideband reflectance and eSR testing. Ipsilateral reflexes were measured with three probes: a broadband chirp (swept from 200 to 8000 Hz), a 226 Hz tone, and a 678 Hz tone. Wideband reflectance measures acquired from 28 adults without CIs and with normal middle ear function served as a normative data set for comparison.

RESULTS

Considering the group data, average reflectance was significantly greater for ears with CIs across 250 to 891 Hz and 4238 to 4490 Hz compared with the normative data set, although individual reflectance curves were variable. Some CI recipients also had low 226 Hz admittance, which contributed to the group finding, considering the control group had clinically normal 226 Hz admittance by design. Electrically evoked stapedial reflexes were measurable in nine of 14 ears (64.3%) and in 24 of 46 electrodes (52.5%) tested. Reflex-induced changes in reflectance patterns were unique to the participant/ear, but similar across activators (electrodes) within a given ear. In addition, reflectance values at or above 1000 Hz were affected most by activating the stapedial reflex, even in ears with clinically normal 226 Hz admittance. This is a higher-frequency range than has been reported for acoustically evoked reflex-induced reflectance changes and is consistent with increased middle ear stiffness at rest. Electrically evoked reflexes could be measured more often with the 678 Hz or the broadband probe compared with the 226 Hz probe tone. Although reflex thresholds were lower with the broadband probe compared with the 678 Hz probe in 16 of 24 conditions, this was not a statistically significant finding (Wilcoxon signed-rank test; p = 0.072).

CONCLUSIONS

The applications of wideband acoustic immittance measurements (reflectance and reflexes) should also be considered for ears with CIs. Further work is needed to describe changes across time in ears with CIs to more fully understand the reflectance pattern indicating increased middle ear stiffness and to optimize measuring eSRs with a broadband probe.

"Benefits of the pedicled osteoplastic flap as a surgical approach of mastoidectomy in cochlear implant surgery"

OBJECTIVE

To evaluate the esthetic and functional results of an osteoplastic flap for mastoid cavity closure in cochlear implant surgery.

STUDY DESIGN

Double-blind, prospective, randomized clinical trial.

SETTING

tertiary referral center.

INTERVENTION(S)

On hundred and twenty-six patients were randomized in 2 groups for cochlear implant surgery. Cases (n: 63) underwent simple mastoidectomy using an anteriorly pedicled osteoplastic flap for mastoid closure. In controls (n: 63), a traditional periosteal flap was used. Evaluation with the POSAS questionnaire was performed 1 year after surgery to assess surgical wound esthetics. Sixteen patients from each group had postoperative CT-scans and wideband tympanometry to assess mastoid aeration and middle ear absorbance. Gender and time after surgery were correlated.

MAIN OUTCOME MEASURE(S)

Evaluation of the quality of the surgical wound with the application of a questionnaire validated in the medical literature and translated into Portuguese language called POSAS, considering the perception of the blinded patient and doctor regarding the surgical technique proceeded. A lower POSAS score suggests better esthetics of the surgical wound. Secondary outcomes are volumetric measurement of aeration inside mastoid cavity using 3D computer tomography exam, which aims to analyze the influence of fibrocicatricial retraction in the surgical wound into the mastoid and the interference of its aeration volume in the absorption of sound in the middle ear, using the wideband tympanometry exam.

RESULTS

The POSAS questionnaire in the Case group showed a lower level of local pain and itchiness, a skin color and thickness more similar to the surrounding skin and less irregularity and stiffness, with no influence from time after surgery and gender compared to the Control group. The median tomographic volume was 6.37 cc in the cases and 4.60 cc in controls. Wideband tympanometry showed general smaller sound absorbance in the Case group results, specially, at 1000 Hz frequency. No intraoperative or postoperative complications were observed with the osteoplastic flap.

CONCLUSIONS

This technique is an effective and safe alternative to alleviate common problems of mastoid surgery for cochlear implantation. In addition to esthetic benefits, it has less interference in middle ear physiology of sound absorbance and less fibrous tissue into the mastoid cavity during the follow-up of more than 1 year.

Improving the Differential Diagnosis of Otitis Media With Effusion Using Wideband Acoustic Immittance

OBJECTIVES

The objective of this work is to determine whether there is a systematic effect of middle ear effusion volume on wideband acoustic immittance in children with surgically confirmed otitis media with effusion.

DESIGN

Wideband acoustic immittance was measured in 49 ears from children (9 months to 11 years) who had a diagnosis of otitis media with effusion and compared to 14 ears from children (10 months to 10 years) without a recent history of otitis media. For children with otitis media with effusion, wideband acoustic immittance testing took place in the child's preoperative waiting room before surgical placement of tympanostomy tubes. Testing was completed in a pressurized condition (wideband tympanometry) for all ears as well as in an ambient condition in a subset of ears. Intraoperative findings regarding effusion volume were reported by the surgeons immediately before tube placement and confirmed following myringotomy. This classified the volume of effusion as compared to middle ear volume categorically as either full, partial, or clear of effusion. The type of wideband acoustic immittance explored in this work was absorbance. Absorbance responses were grouped based on effusion volume into one of four groups: full effusions, partial effusions, ears clear of effusion at the time of surgery, and normal control ears. Standard tympanometry was also completed on all ears.

RESULTS

Absorbance is systematically reduced as the volume of the middle ear effusion increases. This reduction is present at most frequencies but is greatest in the frequency range from 1 to 5 kHz. A multivariate logistic regression approach was utilized to classify ears based on effusion volume. The regression approach classified ears as effusion present (full and partial ears) or absent (clear ears and normal control ears) with 100% accuracy, ears with effusion present as either partial or full with 100% accuracy, and ears without effusion as either normal control ears or ears clear of effusion with 75% accuracy. Regression performance was also explored when the dataset was split into a training set (70% of the data) and a validation test set (30% of the data) to simulate how this approach would perform on unseen data in a clinical setting. Accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve are reported. Overall, this approach demonstrates high sensitivity and specificity for classifying ears as effusion being present or absent and as present effusions being full or partial with areas under the curve ranging from 1 to 0.944. Despite the lack of effusion present in both clear ears and normal control ears, this approach was able to distinguish between these ears, but with a more moderate sensitivity and specificity. No systematic effect of effusion volume was found on standard tympanometry.

CONCLUSIONS

Wideband acoustic immittance, and more specifically, absorbance, is a strong and sensitive indicator of the volume of a middle ear effusion in children with otitis media with effusion.

Assessment of Pediatric Middle Ear Effusions With Wideband Tympanometry

OBJECTIVE

To determine if wideband tympanometry (WBT) can differentiate types of middle ear effusion (MEE): serous, mucoid, and purulent.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary care children's hospital.

METHODS

Children who met American Academy of Otolaryngology-Head and Neck Surgery's guidelines for ventilation tube insertion had WBT after anesthesia induction but before tympanotomy. MEE was categorized into 1 of 4 comparison groups: serous effusion, mucoid effusion, purulent effusion, or no effusion. WBT measurements were averaged to 16 one-third octave frequency bands, and comparison of the absorbance patterns for each MEE type was performed through a linear mixed effects model.

RESULTS

A total of 118 children (211 ears) were included: 47 females (39.8%) and 71 males (60.2%). The mean age was 2.73 years (95% CI, 2.25-3.22); mean weight, 14.35 kg (95% CI, 12.85-15.85); and mean Z score, 1.13 (95% CI, -0.64 to 2.33). Effusions included 61 mucoid (28.9%), 30 purulent (14.2%), and 14 serous (6.6%), with 106 (50.2%) having no effusion. No significant differences were found for sex, race, age, weight, or Z score among the 4 types of effusion (P < .05). WBT showed a significant difference in median absorption among the effusion groups (P < .001), with a medium effect size of 0.35.

CONCLUSIONS

WBT has potential use to differentiate types of MEE and should be studied further as a tool for investigating how the natural history and management of serous and mucoid effusions may differ.

Peripheral Auditory Involvement in Childhood Listening Difficulty

OBJECTIVES

This study tested the hypothesis that undetected peripheral hearing impairment occurs in children with idiopathic listening difficulties (LiDs), as reported by caregivers using the Evaluation of Children"s Listening and Processing Skills (ECLiPS) validated questionnaire, compared with children with typically developed (TD) listening abilities.

DESIGN

Children with LiD aged 6-14 years old (n = 60, mean age = 9.9 yr) and 54 typical age matched children were recruited from audiology clinical records and from IRB-approved advertisements at hospital locations and in the local and regional areas. Both groups completed standard and extended high-frequency (EHF) pure-tone audiometry, wideband absorbance tympanometry and middle ear muscle reflexes, distortion product and chirp transient evoked otoacoustic emissions. Univariate and multivariate mixed models and multiple regression analysis were used to examine group differences and continuous performance, as well as the influence of demographic factors and pressure equalization (PE) tube history.

RESULTS

There were no significant group differences between the LiD and TD groups for any of the auditory measures tested. However, analyses across all children showed that EHF hearing thresholds, wideband tympanometry, contralateral middle ear muscle reflexes, distortion product, and transient-evoked otoacoustic emissions were related to a history of PE tube surgery. The physiologic measures were also associated with EHF hearing loss, secondary to PE tube history.

CONCLUSIONS

Overall, the results of this study in a sample of children with validated LiD compared with a TD group matched for age and sex showed no significant differences in peripheral function using highly sensitive auditory measures. Histories of PE tube surgery were significantly related to EHF hearing and to a range of physiologic measures in the combined sample.

Wideband tympanometry findings in inner ear malformations

OBJECTIVE

The deficits in the cochlea which is at the one end of the ear sound transfer system, may effect middle ear functions. Wideband typanometry (WBT) is frequently used to evaluate these transfer functions which play a crucial role in setting the impedance matching between the external ear and the cochlea. To this end, the aim of this study was to investigate the ear transfer functions in inner ear malformations via WBT, and to question whether these functions change depending on the types of inner ear malformation.

METHODS

This prospective case-control study was conducted in a university hospital. One hundered-fifty-seven ears (aged 3-37 years) under the groups of cochlear hypoplasia, incomplete partition I, incomplete partition II, cochlear aplasia and complete labyrinthine aplasia were evaluated. In the control group, 30 ears with normal hearing were enrolled and WBT was carried out. Tympanometric peak pressure, equivalent middle ear volume, static admittance, tympanogram width, resonance frequency, average wideband tympanometry and absorbance measurements were analyzed.

RESULTS

The inner ear malformation groups demonstrated statistically significant differences than the control group and from each other in terms of traditional tympanometric parameters and WBT test parameters (p<0.05). The most remarkable difference was between the group of complete labyrinthine aplasia and the control group, most probably because of complete labyrinthine aplasia's structural effects. However, on some parameters, incomplete partition II and the control group showed similarities. In absorbance measurements, there was significant difference between all patient groups and the control group, especially at high frequencies (p<0.05). The largest difference was between the control group and the group of complete labyrinthine aplasia which has revealed the lowest absorbance values (p<0.05). In averaged-wideband tympanogram analysis, all patient groups obtained a lower amplitude peak than the control group; complete labyrinthine aplasia group had the flattest peaked amplitude, while the incomplete partition II group had a near-normal curve.

CONCLUSION

The results of the study revealed the distinctive effects of inner ear malformations in middle ear transfer functions. It is concluded that the absence of inner ear structures causes negative effects on energy absorbance and the other transfer functions of the middle ear. WBT may provide additional information on diagnosis of patients with inner ear malformations.

Longitudinal Development of Distortion Product Otoacoustic Emissions in Infants With Normal Hearing

OBJECTIVES

The purpose of this study was to describe normal characteristics of distortion product otoacoustic emission (DPOAE) signal and noise level in a group of newborns and infants with normal hearing followed longitudinally from birth to 15 months of age.

DESIGN

This is a prospective, longitudinal study of 231 infants who passed newborn hearing screening and were verified to have normal hearing. Infants were enrolled from a well-baby nursery and two neonatal intensive care units (NICUs) in Cincinnati, OH. Normal hearing was confirmed with threshold auditory brainstem response and visual reinforcement audiometry. DPOAEs were measured in up to four study visits over the first year after birth. Stimulus frequencies f1 and f2 were used with f2/f1 = 1.22, and the DPOAE was recorded at frequency 2f1-f2. A longitudinal repeated-measure linear mixed model design was used to study changes in DPOAE level and noise level as related to age, middle ear transfer, race, and NICU history.

RESULTS

Significant changes in the DPOAE and noise levels occurred from birth to 12 months of age. DPOAE levels were the highest at 1 month of age. The largest decrease in DPOAE level occurred between 1 and 5 months of age in the mid to high frequencies (2 to 8 kHz) with minimal changes occurring between 6, 9, and 12 months of age. The decrease in DPOAE level was significantly related to a decrease in wideband absorbance at the same f2 frequencies. DPOAE noise level increased only slightly with age over the first year with the highest noise levels in the 12-month-old age range. Minor, nonsystematic effects for NICU history, race, and gestational age at birth were found, thus these results were generalizable to commonly seen clinical populations.

CONCLUSIONS

DPOAE levels were related to wideband middle ear absorbance changes in this large sample of infants confirmed to have normal hearing at auditory brainstem response and visual reinforcement audiometry testing. This normative database can be used to evaluate clinical results from birth to 1 year of age. The distributions of DPOAE level and signal to noise ratio data reported herein across frequency and age in normal-hearing infants who were healthy or had NICU histories may be helpful to detect the presence of hearing loss in infants.

Wideband acoustic absorbance in children with Down syndrome

INTRODUCTION

Tympanometry is currently the most frequently used tool for assessing the status of the middle ear, commonly assessed using a single 226Hz tone. However, the use of the Acoustic Immittance Measures with a wideband stimulus is a promising high-resolution evaluation, especially in individuals known to have middle ear alterations, such as Down syndrome patients.

OBJECTIVE

The aim of this study was to analyze the acoustic absorbance measurements in children with Down syndrome.

METHODS

Cross-sectional study, approved by the institution's ethics committee. Data were collected from 30 children, with a mean age of 8.4 years, 15 with Down syndrome (DS-study group) and 15 children with typical development and no hearing complaints (control group). Energy absorbance was measured at frequencies of 226-8000Hz at ambient pressure and at peak pressure as a function of frequency using TITAN equipment. Statistical analysis was performed using the established level of statistical significance of 5%.

RESULTS

With the 226Hz probe tone, 30 ears of the control group and 22 of the study group exhibited Type A tympanograms, whereas Type B was observed in eight children in the study group. The mean acoustic absorbance ratio of the study group was lower than that of the control group at frequencies centered at 2520Hz (p=0.008) for those with normal tympanometry results, and 226-4000Hz (p<0.03) for those with a Type B tympanometry curve.

CONCLUSION

The low energy absorption in the presence of normal tympanograms in children with Down syndrome may suggest middle ear abnormalities.

Emerging Technologies for the Diagnosis of Otitis Media

OBJECTIVE

To review new experimental techniques for the diagnosis of otitis media (OM).

DATA SOURCES

Literature search in English in the following databases: MEDLINE (via PubMed), Ovid Medline, Google Scholar, and Clinical Evidence (BMJ Publishing) between January 1, 2005, and April 30, 2018. Subsequently, articles were reviewed and included only if relevant.

REVIEW METHODS

MeSH terms: ["diagnosis"] AND [all forms of OM] AND ["human"] AND ["ear"] and ["tympanic membrane"]. The retrieved innovative diagnostic techniques rely on and take advantage of the physical properties of the tympanomastoid cavity components: tympanic membrane (TM) thickness, its translucency and compliance; middle ear fluid characteristics; biofilm presence; increased tissue metabolic activity in OM states; and fluid presence in the mastoid cavity. These parameters are taken into account to establish OM diagnosis objectively. We review spectral gradient acoustic reflectometry, digital otoscopy, TM image analysis, multicolor reflectance imaging, anticonfocal middle ear assessment, optical coherence tomography, quantitative pneumatic otoscopy, transmastoid ultrasound, wideband measurements, TM thickness mapping, shortwave infrared imaging, and wideband acoustic transfer functions.

CONCLUSIONS

New experimental techniques are gradually introduced to overcome the limitations of standard otoscopy. The aforementioned techniques are still under investigation and are pending widespread clinical use. The implementation of these techniques in the market is dependent on their success in clinical trials, as well as on their future cost.

IMPLICATION FOR PRACTICE

New techniques for the diagnosis of OM can objectively evaluate the morphology of the TM, determine the presence of middle ear fluid and evaluate its content, and thus potentially replace standard otoscopy.

Diagnosing Middle Ear Pathology in 6- to 9-Month-Old Infants Using Wideband Absorbance: A Risk Prediction Model

PURPOSE

The aim of this study was to develop a risk prediction model for detecting middle ear pathology in 6- to 9-month-old infants using wideband absorbance measures.

METHOD

Two hundred forty-nine infants aged 23-39 weeks (Mdn = 28 weeks) participated in the study. Distortion product otoacoustic emissions and high-frequency tympanometry were tested in both ears of each infant to assess middle ear function. Wideband absorbance was measured at ambient pressure in each participant from 226 to 8000 Hz. Absorbance results from 1 ear of each infant were used to predict middle ear dysfunction, using logistic regression. To develop a model likely to generalize to new infants, the number of variables was reduced using principal component analysis, and a penalty was applied when fitting the model. The model was validated using the opposite ears and with bootstrap resampling. Model performance was evaluated through measures of discrimination and calibration. Discrimination was assessed with the area under the receiver operating characteristic curve (AUC); and calibration, with calibration curves, which plotted actual against predicted probabilities.

RESULTS

AUC of the fitted model was 0.887. The model validated adequately when applied to the opposite ears (AUC = 0.852) and with bootstrap resampling (AUC = 0.874). Calibration was satisfactory, with high agreement between predictions and observed results.

CONCLUSIONS

The risk prediction model had accurate discrimination and satisfactory calibration. Validation results indicate that it may generalize well to new infants. The model could potentially be used in diagnostic and screening settings. In the context of screening, probabilities provide an intuitive and flexible mechanism for setting the referral threshold that is sensitive to the costs associated with true and false-positive outcomes. In a diagnostic setting, predictions could be used to supplement visual inspection of absorbance for individualized diagnoses. Further research assessing the performance and impact of the model in these contexts is warranted.

Wideband acoustic immittance for assessing middle ear functioning for preterm neonates in the neonatal intensive care unit

BACKGROUND

The primary aim of newborn hearing screening is to detect permanent hearing loss. Because otoacoustic emissions (OAEs) and automated auditory brainstem response (AABR) are sensitive to hearing loss, they are often used as screening tools. On the other hand, false-positive results are most often because of transient outer- and middle ear conditions. Wideband acoustic immittance (WAI), which includes physical measures known as reflectance and absorbance, has shown potential for accurate assessment of middle ear function in young infants.

OBJECTIVE

The main objective of this study was to determine the feasibility of WAI as a diagnostic tool for assessing middle ear functioning in preterm neonates in the neonatal intensive care unit (NICU) designed for premature and ill neonates. A further objective was to indicate the difference between the reflectance values of tones and click stimuli.

METHOD

Fifty-six at-risk neonates (30 male and 26 female), with a mean age at testing of 35.6 weeks (range: 32-37 weeks) and a standard deviation of 1.6 from three private hospitals, who passed both the distortion product otoacoustic emission (DPOAE) and AABR tests, were evaluated prior to discharge from the NICU. Neonates who presented with abnormal DPOAE and AABR results were excluded from the study. WAI was measured by using chirp and tone stimuli. In addition to reflectance, the reflectance area index (RAI) values were calculated.

RESULTS

Both tone and chirp stimuli indicated high-power reflectance values below a frequency of 1.5 kHz. Median reflectance reached a minimum of 0.67 at 1 kHz - 2 kHz but increased to 0.7 below 1 kHz and 0.72 above 2 kHz for the tone stimuli. For chirp stimuli, the median reflectance reached a minimum of 0.51 at 1 kHz - 2 kHz but increased to 0.68 below 1 kHz and decreased to 0.5 above 2 kHz. A comparison between the present study and previous studies on WAI indicated a substantial variability across all frequency ranges.

CONCLUSION

These WAI measurements conducted on at-risk preterm NICU neonates (mean age at testing: 35.6 weeks, range: 32-37 weeks) identified WAI patterns not previously reported in the literature. High reflective values were obtained across all frequency ranges. The age of the neonates when tested might have influenced the results. The neonates included in the present study were very young preterm neonates compared to the ages of neonates in previous studies. WAI measured in at-risk preterm neonates in the NICU was variable with environmental and internal noise influences. Transient conditions affecting the sound-conduction pathway might have influenced the results. Additional research is required to investigate WAI testing in ears with and without middle ear dysfunction. The findings of the current study imply that in preterm neonates it was not possible to determine the feasibility of WAI as a diagnostic tool to differentiate between ears with and without middle ear pathology.

Maturation of middle ear transmission in children

The goal of the current study was to characterize the normative features of wideband acoustic immittance in children for describing the functional maturation of the middle ear in 5 to 12-year-old children. Absorbance and group delay were measured in adults and three groups of children, 5-6, 7-9 and 10-12-year-olds, in a cross-sectional design. Absorbance showed significant effects of the age group in four out of ten center frequencies of one-half-octave bins from 211 to 6000 Hz, while there was no significant effect for group delay at any frequency. Older children (10-12 years) showed absorbance similar to adults. Test-retest reliability was high for absorbance for all age groups. However, group delay was modestly reliable only for adults. We conclude that the middle ear transmission follows a protracted period of maturation for high frequencies and reaches adult-like feature by 10-12 years of age.

[Detection of the Presence of Middle-ear Effusion with Wideband Absorbance Tympanometry]

This study evaluated the ability of wideband absorbance (AB) to predict the presence of middle-ear effusion (MEE) in ears with a flat (type B) 226 Hz tympanogram (TG). AB measures were obtained in a no MEE group of 8 ears with a flat TG and a MEE group of 19 ears also with a flat TG. AB was significantly small at frequencies 2 and 4 kHz in the MEE group than in the no MEE group. Based on our results, it appeared that AB could detect MEE with higher specificity than conventional tympanometry. The presence or absence of MEE could be distinguished based on the average AB using 1, 2, and 4 kHz, with 40% as the cutoff point.

Otitis media

Otitis media (OM) or middle ear inflammation is a spectrum of diseases, including acute otitis media (AOM), otitis media with effusion (OME; 'glue ear') and chronic suppurative otitis media (CSOM). OM is among the most common diseases in young children worldwide. Although OM may resolve spontaneously without complications, it can be associated with hearing loss and life-long sequelae. In developing countries, CSOM is a leading cause of hearing loss. OM can be of bacterial or viral origin; during 'colds', viruses can ascend through the Eustachian tube to the middle ear and pave the way for bacterial otopathogens that reside in the nasopharynx. Diagnosis depends on typical signs and symptoms, such as acute ear pain and bulging of the tympanic membrane (eardrum) for AOM and hearing loss for OME; diagnostic modalities include (pneumatic) otoscopy, tympanometry and audiometry. Symptomatic management of ear pain and fever is the mainstay of AOM treatment, reserving antibiotics for children with severe, persistent or recurrent infections. Management of OME largely consists of watchful waiting, with ventilation (tympanostomy) tubes primarily for children with chronic effusions and hearing loss, developmental delays or learning difficulties. The role of hearing aids to alleviate symptoms of hearing loss in the management of OME needs further study. Insertion of ventilation tubes and adenoidectomy are common operations for recurrent AOM to prevent recurrences, but their effectiveness is still debated. Despite reports of a decline in the incidence of OM over the past decade, attributed to the implementation of clinical guidelines that promote accurate diagnosis and judicious use of antibiotics and to pneumococcal conjugate vaccination, OM continues to be a leading cause for medical consultation, antibiotic prescription and surgery in high-income countries.

Clinical Practice Guideline: Otitis Media with Effusion (Update)

OBJECTIVE

This update of a 2004 guideline codeveloped by the American Academy of Otolaryngology-Head and Neck Surgery Foundation, the American Academy of Pediatrics, and the American Academy of Family Physicians, provides evidence-based recommendations to manage otitis media with effusion (OME), defined as the presence of fluid in the middle ear without signs or symptoms of acute ear infection. Changes from the prior guideline include consumer advocates added to the update group, evidence from 4 new clinical practice guidelines, 20 new systematic reviews, and 49 randomized control trials, enhanced emphasis on patient education and shared decision making, a new algorithm to clarify action statement relationships, and new and expanded recommendations for the diagnosis and management of OME.

PURPOSE

The purpose of this multidisciplinary guideline is to identify quality improvement opportunities in managing OME and to create explicit and actionable recommendations to implement these opportunities in clinical practice. Specifically, the goals are to improve diagnostic accuracy, identify children who are most susceptible to developmental sequelae from OME, and educate clinicians and patients regarding the favorable natural history of most OME and the clinical benefits for medical therapy (eg, steroids, antihistamines, decongestants). Additional goals relate to OME surveillance, hearing and language evaluation, and management of OME detected by newborn screening. The target patient for the guideline is a child aged 2 months through 12 years with OME, with or without developmental disabilities or underlying conditions that predispose to OME and its sequelae. The guideline is intended for all clinicians who are likely to diagnose and manage children with OME, and it applies to any setting in which OME would be identified, monitored, or managed. This guideline, however, does not apply to patients <2 months or >12 years old.

ACTION STATEMENTS

The update group made strong recommendations that clinicians (1) should document the presence of middle ear effusion with pneumatic otoscopy when diagnosing OME in a child; (2) should perform pneumatic otoscopy to assess for OME in a child with otalgia, hearing loss, or both; (3) should obtain tympanometry in children with suspected OME for whom the diagnosis is uncertain after performing (or attempting) pneumatic otoscopy; (4) should manage the child with OME who is not at risk with watchful waiting for 3 months from the date of effusion onset (if known) or 3 months from the date of diagnosis (if onset is unknown); (5) should recommend against using intranasal or systemic steroids for treating OME; (6) should recommend against using systemic antibiotics for treating OME; and (7) should recommend against using antihistamines, decongestants, or both for treating OME.The update group made recommendations that clinicians (1) should document in the medical record counseling of parents of infants with OME who fail a newborn screening regarding the importance of follow-up to ensure that hearing is normal when OME resolves and to exclude an underlying sensorineural hearing loss; (2) should determine if a child with OME is at increased risk for speech, language, or learning problems from middle ear effusion because of baseline sensory, physical, cognitive, or behavioral factors; (3) should evaluate at-risk children for OME at the time of diagnosis of an at-risk condition and at 12 to 18 months of age (if diagnosed as being at risk prior to this time); (4) should not routinely screen children for OME who are not at risk and do not have symptoms that may be attributable to OME, such as hearing difficulties, balance (vestibular) problems, poor school performance, behavioral problems, or ear discomfort; (5) should educate children with OME and their families regarding the natural history of OME, need for follow-up, and the possible sequelae; (6) should obtain an age-appropriate hearing test if OME persists for 3 months or longer OR for OME of any duration in an at-risk child; (7) should counsel families of children with bilateral OME and documented hearing loss about the potential impact on speech and language development; (8) should reevaluate, at 3- to 6-month intervals, children with chronic OME until the effusion is no longer present, significant hearing loss is identified, or structural abnormalities of the eardrum or middle ear are suspected; (9) should recommend tympanostomy tubes when surgery is performed for OME in a child <4 years old; adenoidectomy should not be performed unless a distinct indication exists (nasal obstruction, chronic adenoiditis); (10) should recommend tympanostomy tubes, adenoidectomy, or both when surgery is performed for OME in a child ≥4 years old; and (11) should document resolution of OME, improved hearing, or improved quality of life when managing a child with OME.

Predictions of middle-ear and passive cochlear mechanics using a finite element model of the pediatric ear

A finite element (FE) model was developed based on histological sections of a temporal bone of a 4-year-old child to simulate middle-ear and cochlear function in ears with normal hearing and otitis media. This pediatric model of the normal ear, consisting of an ear canal, middle ear, and spiral cochlea, was first validated with published energy absorbance (EA) measurements in young children with normal ears. The model was used to simulate EA in an ear with middle-ear effusion, whose results were compared to clinical EA measurements. The spiral cochlea component of the model was constructed under the assumption that the mechanics were passive. The FE model predicted middle-ear transfer functions between the ear canal and cochlea. Effects of ear structure and mechanical properties of soft tissues were compared in model predictions for the pediatric and adult ears. EA responses are predicted to differ between adult and pediatric ears due to differences in the stiffness and damping of soft tissues within the ear, and any residual geometrical differences between the adult ear and pediatric ear at age 4 years. The results have significance for predicting effects of otitis media in children.

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

OBJECTIVE

The 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.

METHODS

A 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 -200daPa, was evaluated in terms of the sound pressure level (SPL) in the ear canal, resonance frequency (RF) and displacement (ΔSPL).

RESULTS

Application 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 (0daPa). At -200daPa, 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.

CONCLUSIONS

While 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 -200daPa 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.

Longitudinal development of wideband reflectance tympanometry in normal and at-risk infants

PURPOSE

The goals of this study were to measure normal characteristics of ambient and tympanometric wideband acoustic reflectance, which was parameterized by absorbance and group delay, in newborns cared for in well-baby and Neonatal Intensive Care Unit (NICU) nurseries, and to characterize the normal development of reflectance over the first year after birth in a group of infants with clinically normal hearing status followed longitudinally from birth to one year of age.

METHODS

Infants were recruited from a well-baby and NICU nursery, passed newborn otoacoustic emissions (OAE) and automated auditory brainstem response (ABR) tests as well as follow-up diagnostic ABR and audiometry. They were tested longitudinally for up to one year using a wideband middle ear acoustic test battery consisting of tympanometry and ambient-pressure tests. Results were analyzed for ambient reflectance across frequency and tympanometric reflectance across frequency and pressure.

RESULTS

Wideband absorbance and group delay showed large effects of age in the first 6 months. Immature absorbance and group delay patterns were apparent in the low frequencies at birth and one month, but changed substantially to a more adult-like pattern by age 6 months for both ambient and tympanometric variables. Area and length of the ear canal estimated acoustically increased up to age 1 year. Effects of race (African American and others compared to Caucasian) were found in combination with age effects. Mean and confidence intervals are provided for use as a normative longitudinal database for newborns and infants up to one year of age, for both well-baby and NICU infants.

Air-leak effects on ear-canal acoustic absorbance

OBJECTIVE

Accurate ear-canal acoustic measurements, such as wideband acoustic admittance, absorbance, and otoacoustic emissions, require that the measurement probe be tightly sealed in the ear canal. Air leaks can compromise the validity of the measurements, interfere with calibrations, and increase variability. There are no established procedures for determining the presence of air leaks or criteria for what size leak would affect the accuracy of ear-canal acoustic measurements. The purpose of this study was to determine ways to quantify the effects of air leaks and to develop objective criteria to detect their presence.

DESIGN

Air leaks were simulated by modifying the foam tips that are used with the measurement probe through insertion of thin plastic tubing. To analyze the effect of air leaks, acoustic measurements were taken with both modified and unmodified foam tips in brass-tube cavities and human ear canals. Measurements were initially made in cavities to determine the range of critical leaks. Subsequently, data were collected in ears of 21 adults with normal hearing and normal middle-ear function. Four acoustic metrics were used for predicting the presence of air leaks and for quantifying these leaks: (1) low-frequency admittance phase (averaged over 0.1-0.2 kHz), (2) low-frequency absorbance, (3) the ratio of compliance volume to physical volume (CV/PV), and (4) the air-leak resonance frequency. The outcome variable in this analysis was the absorbance change (Δabsorbance), which was calculated in eight frequency bands.

RESULTS

The trends were similar for both the brass cavities and the ear canals. ΔAbsorbance generally increased with air-leak size and was largest for the lower frequency bands (0.1-0.2 and 0.2-0.5 kHz). Air-leak effects were observed in frequencies up to 10 kHz, but their effects above 1 kHz were unpredictable. These high-frequency air leaks were larger in brass cavities than in ear canals. Each of the four predictor variables exhibited consistent dependence on air-leak size. Low-frequency admittance phase and CV/PV decreased, while low-frequency absorbance and the air-leak resonance frequency increased.

CONCLUSION

The effect of air leaks can be significant when their equivalent diameter exceeds 0.01 in. The observed effects were greatest at low frequencies where air leaks caused absorbance to increase. Recommended criteria for detecting air leaks include the following: when the frequency range of interest extends as low as 0.1 kHz, low-frequency absorbance should be ≤0.20 and low-frequency admittance phase ≥61 degrees. For frequency ranges as low as 0.2 kHz, low-frequency absorbance should be ≤0.29 and low-frequency admittance phase ≥44 degrees.

Acoustic Immittance, Absorbance, and Reflectance in the Human Ear Canal

Ear canal measurements of acoustic immittance (a term that groups impedance and its inverse, admittance) and the related quantities of acoustic reflectance and power absorbance have been used to assess auditory function and aid in the differential diagnosis of conductive hearing loss for over 50 years. The change in such quantities after stimulation of the acoustic reflex also has been used in diagnosis. In this article, we define these quantities, describe how they are commonly measured, and discuss appropriate calibration procedures and standards necessary for accurate immittance/reflectance measurements.

An overview of wideband immittance measurements techniques and terminology: you say absorbance, I say reflectance

This article reviews the relationships among different acoustic measurements of the mobility of the tympanic membrane, including impedance, admittance, reflectance, and absorbance, which the authors group under the rubric of immittance measures. Each of these quantities is defined and related to the others. The relationship is most easily grasped in terms of a straight rigid ear canal of uniform area terminated by a uniform middle ear immittance placed perpendicular to the long axis of the ear canal. Complications due to variations from this geometry are discussed. Different methods for measuring these quantities are described, and the assumptions inherent within each method are made explicit. The benefits of wideband measurements of these quantities are described, as are the benefits and limitations of different components of immittance and reflectance/absorbance. While power reflectance (the square of the magnitude of pressure reflectance) is relatively invariant along the length of the ear canal, it has the disadvantage that it ignores phase information that may be useful in assessing the presence of acoustic leaks in ear-canal measurements and identifying other potential error sources. A combination of reflectance and impedance magnitude and angle give a more complete description of the middle ear from measurements in the ear canal.