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

High frequency (1000 Hz) tympanometry in six-month-old infants

Objectives: High frequency tympanometry (HFT) using a 1000 Hz probe tone is recommended for infants from birth to six months of age. However, there is limited normative HFT data outside the newborn period. The objective of this study was to describe HFT data in healthy six-month-old infants. Methods: HFT and distortion product otoacoustic emission (DPOAE) tests were performed on 168 six-month-old full-term healthy infants. Ears that passed DPOAEs and had a single-peaked tympanogram were included for analysis. The tympanometric measures included in the normative HFT data were tympanometric peak pressure (TPP), peak compensated static admittance (Ytm) and tympanometric width (TW). Results: A total of 118 ears from 118 infants who passed DPOAE and had single-peaked tympanograms were included in the analysis. Normative data were presented for TPP, Ytm and TW. A comparison of the present study with studies on neonates and younger infants revealed significantly higher mean Ytm and lower mean TPP for six-month-old-infants. Conclusion: Significant differences in HFT findings between neonates and six-month-old infants suggest a developmental trend and confirm the need for separate age-appropriate norms for the tympanometric measures. Normative HFT data described in the present study may provide useful information for optimizing the diagnosis of conductive conditions in six-month-old infants

Tonal Masking Level Differences in Aboriginal Children: Implications for Binaural Interaction, Auditory Processing Disorders and Education

The masking level difference (MLD) is a psychoacoustic measure of binaural interaction and central auditory processing related to extracting signals from noise backgrounds. It represents the improvement in threshold sensitivity under antiphasic listening conditions relative to homophasic conditions. A low frequency pure tone (500 Hz) was presented in-phase (So) binaurally to the subject in the presence of a phasic masker (No). The behavioural threshold obtained at this condition was used as a reference. The behavioural threshold was again determined with the pure tone stimulus presented antiphasically (Sπ), and the difference in thresholds was calculated to determine the MLD. The MLD was measured for a 500 Hz pure tone in 36 Aboriginal children (16 males and 20 females) from an Aboriginal community school (Nguiu, Tiwi Islands) where conductive hearing loss, due to otitis media, is endemic. The control group consisted of 62 normal-hearing children (40 males and 22 females) from a private school in Darwin. Aboriginal children showed a mean MLD of 7.76 dB whereas the control group exhibited a mean MLD of 11.21 dB. Aboriginal children showed a consistently lower MLD than non-Aboriginal normal-hearing children. Auditory processing disorders (APDs) have been shown to be related to early auditory deprivation, a common feature of chronic conductive hearing loss observed frequently in Aboriginal children. Thus, the MLD provides a metric for assessing binaural hearing abilities which may be relevant to the assessment of APD and hearing aid fitting. The MLD is a less linguistically, less culturally biased predictive measure and may be more easily administered than many speech and language test procedures used in diagnosing APD

Perceptual Consequences of Conductive Hearing Loss: Speech Perception in Indigenous Students Learning English as a School Language

The high incidence of ear disease and hearing loss in Australian Indigenous children is well documented. This study aims to consider the effect of hearing loss and native-language phonology on learning English by Australian Indigenous children. Twenty-one standard Australian English consonants were considered in a consonant-vowel (CV) context. Each consonant was paired with each other to yield 'same' and 'different' consonant pairs. The participants were classified into three groups: (1) English speaking, non-Indigenous children without history of hearing loss and otitis media (three males, four females, mean age 13.7 years); (2) Indigenous children speaking Tiwi as their native language, without history of hearing loss and otitis media and learning English as a second language (two males, three females, mean age 12.1 yrs) and (3) Indigenous children speaking Tiwi as their native language, with a history of hearing loss and otitis media since childhood (six females, mean age 13.1 years). The reaction time from the onset of the second word of the pair to the pressing of a 'same' or 'different' button was measured. The results demonstrated that discrimination of consonants was differentially affected by differences in language. Hearing loss further complicated the difficulties that a child was already having with English. Hearing loss tended to affect discrimination of English consonants more than those in the native language. The study suggests that amplification alone does not suffice and recommended that phonological awareness programs, with or without amplification, need to be part of a reading program from preschool with Indigenous children learning English as a 'school' language

Effect of negative middle ear pressure and compensated pressure on wideband absorbance and otoacoustic emissions in children

Objective: This study investigated pressurized transient evoked otoacoustic emission (TEOAE) responses and wideband absorbance (WBA) in healthy ears and ears with negative middle ear pressure (NMEP).Method: In this cross-sectional study, TEOAE amplitude, signal-to-noise ratio, and WBA were measured at ambient and tympanometric peak pressure (TPP) in 36 ears from 25 subjects with healthy ears (age range: 3.1-13.0 years) and 88 ears from 76 patients with NMEP (age range: 2.0-13.1 years), divided into 3 groups based on NMEP (Group 1 with TPP between -101 and -200 daPa, Group 2 with TPP between -201 and -300 daPa, and Group 3 with TPP between -301 and -400 daPa).Results: Mean TEOAE amplitude, signal-to-noise ratio, and WBA were increased at TPP relative to that measured at ambient pressure between 0.8 and 1.5 kHz. Further decrease in TPP beyond -300 daPa did not result in further increases in the mean TEOAE or WBA at TPP. The correlation between TEOAE and WBA was dependent on the frequency, pressure conditions, and subject group. There was no difference in pass rates between the 2 pressure conditions for the control group, while the 3 NMEP groups demonstrated an improvement in pass rates at TPP. With pressurization, the false alarm rate for TEOAE due to NMEP was reduced by 17.8% for NMEP Group 1, 29.2% for NMEP Group 2, and 15.8% for NMEP Group 3.Conclusion: Results demonstrated the feasibility and clinical benefits of measuring TEOAE and WBA under pressurized conditions. Pressurized TEOAE and WBA should be used for assessment of ears with NMEP in hearing screening programs to reduce false alarm rates

Conductive hearing loss and middle ear pathology in young infants referred through newborn universal hearing screening program in Australia

Background: Although newborn hearing screening programs have been introduced in most states in Australia, the prevalence of conductive hearing loss and middle ear pathology in the infants referred through these programs is not known. Purpose: This study was designed to (1) evaluate the prevalence of conductive hearing loss and middle ear pathology in infants referred by a newborn hearing screening program in north Queensland, (2) compare prevalence rates of conductive hearing loss andmiddle ear pathology in indigenous and nonindigenous infants, and (3) review the outcomes of those infants diagnosed with conductive hearing loss and middle ear pathology. Research Design: Retrospective chart review of infants referred to the Audiology Department of The Townsville Hospital was conducted. Study Sample: Chart review of 234 infants referred for one or both ears from a newborn hearing screening program in north Queensland was conducted. A total of 211 infants attended the diagnostic appointment. Review appointments to monitor hearing status were completed for 46 infants with middle ear pathology or conductive hearing loss. Data Collection and Analysis: Diagnosis of hearing impairment was made using an age-appropriate battery of audiological tests. Results were analyzed for both initial and review appointments. Results: Mean age at initial diagnostic assessment was 47.5 days (SD 5 31.3). Of the 69 infants with middle ear pathology during initial diagnostic assessment, 18 had middle ear pathology with normal hearing, 47 had conductive hearing loss, and 4 had mixed hearing loss. Prevalence of conductive hearing loss in the newborns was 2.97 per 1,000 while prevalence of middle ear pathology (with or without conductive hearing loss) was 4.36 per 1,000. Indigenous Australians or Aboriginal and Torres Strait Islander (ATSI) infants had a significantly higher prevalence of conductive hearing loss and middle ear pathology than non-ATSI infants (35.19 and 44.45% vs 17.83 and 28.66%, respectively). ATSI infants also showed poor resolution of conductive hearing loss over time with 66.67% of ATSI infants reviewed showing persistent conductive hearing loss compared to 17.86% of non-ATSI infants. Medicalmanagement of 17 infants with persistent conductive hearing loss includedmonitoring, antibiotic treatment, examination under anesthesia, and grommet insertion. Conclusions: Conductive hearing loss was found to be a common diagnosis among infants referred through screening. ATSI infants had significantly higher rates of middle ear pathology and conductive hearing loss at birth and showed poor resolution of middle ear pathology over time compared to non-ATSI infants. Future research using a direct measure of middle ear function as an adjunct to the automated auditory brainstem response screening tool to distinguish conductive from sensorineural hearing loss may facilitate prioritization of infants for assessment, thus reducing parental anxiety and streamlining the management strategies for the respective types of hearing loss

Wideband absorbance in ears with retraction pockets and cholesteatomas: a preliminary study

Objectives: The objective of this study was to describe wideband absorbance (WBA) findings in patients with cholesteatomas and retraction pockets (RPs). Design: In this prospective study, tympanometry, audiometry, and wideband tympanometry (WBT) were performed on 27 ears with an RP (eight with epitympanic RP and 19 ears with mesotympanic RP), 39 ears with a cholesteatoma (23 ears with epitympanic and 16 ears with mesotympanic cholesteatomas [MCs]), and 49 healthy ears serving as controls. Results: Mean WBA at ambient pressure (WBAamb) of both experimental groups was reduced significantly between 0.8 and 5 kHz relative to the control group. The difference between mean WBAamb and mean WBA at tympanometric peak pressure (WBATPP) was greater for the RP (0.12–0.16 between 0.5 and 1.5 kHz) than for the cholesteatoma group (0.03–0.11 between 0.6 and 3 kHz). Mean WBAamb of both epitympanic RP (ERP) and epitympanic cholesteatoma (EC) subgroups was significantly lower than that of the control group. Mean WBATPP of the ERP subgroup attained normal levels as per the control group, while mean WBATPP of EC subgroup was significantly lower than that of the control group at 0.8 to 1.5 kHz and 4 to 5 kHz. In contrast, both mesotympanic RP and MC subgroups demonstrated similar mean WBAamb and WBATPP values. No significant differences in WBAamb and WBATPP results between the RP and cholesteatomas groups were observed. Receiver operating characteristic (ROC) analyses indicated that the area under the ROC curve for distinguishing between the RP and cholesteatomas groups ranged from 0.44 to 0.60, indicating low accuracy in separating the two groups. Conclusion: While it is not possible to distinguish between the RP and cholesteatomas groups based on the WBAamb and WBATPP results, it is potentially feasible to differentiate between the EC and ERP conditions. Further study using a large clinical sample is recommended to determine the sensitivity and specificity of the WBA test to identify the EC and ERP conditions

Normative wideband acoustic immittance measurements in Caucasian and Aboriginal children

Purpose: The aims of this study were to develop normative data for wideband acoustic immittance (WAI) measures in Caucasian and Australian Aboriginal children and compare absorbance measured at 0 daPa (WBA(0) ) and tympanometric peak pressure (TPP; WBA(TPP)) between the 2 groups of children. Additional WAI measures included resonance frequency, equivalent ear canal volume, TPP, admittance magnitude (YM), and phase angle (YA).Method: A total of 171 ears from 171 Caucasian children and 87 ears from 87 Aboriginal children who passed a test battery consisting of 226-Hz tympanometry, transient evoked otoacoustic emissions, and pure tone audiometry were included in the study. WAI measures were obtained under pressurized conditions using wideband tympanometry. Data for WBA(0,) WBA(TPP), YM, and YA were averaged in one-third octave frequencies from 0.25 to 8 kHz.Results: There was no significant ear effect on all of the 7 measures for both groups of children. Similarly, there was no significant gender effect on all measures except for WBA(TPP) in Aboriginal children. Aboriginal boys had significantly higher WBA(TPP) than girls at 1.5 and 2 kHz. A significant effect of ethnicity was also noted for WBA(TPP) at 3, 4, and 8 kHz, with Caucasian children demonstrating higher WBA(TPP) than Aboriginal children. However, the effect size and observed power of the analyses were small for both effects.Conclusion: This study developed normative data for 7 WAI measures, namely, WBA(0) , WBA(TPP), TPP, Veq, RF, YM, and YA, for Caucasian and Aboriginal children. In view of the high similarity of the normative data between Caucasian and Aboriginal children, it was concluded that separate ethnic-specific norms are not required for diagnostic purposes

Binaural Speech Discrimination in Noise With Bone Conduction: Applications for Hearing Loss in High-Risk Populations

The use of bone conducted signals for children with chronic otitis media may be considered when earphones or hearing aid receivers are contraindicated because of discharging or painful ears. The use of FM hearing aids in the classroom coupled to a bone conduction (BC) transducer has beneficial application even when considering improved binaural function. This study investigated speech discrimination in diotic and dichotic noise. Confusion matrices were obtained for consonant-vowel (CV) exemplars presented to normal hearing subjects through BC in both correlated and uncorrelated noise. Thirty-six university-aged listeners served as subjects. The CV exemplars were presented randomly, 20 times each, for a total presentation of 420 stimuli for each subject. The stimuli were presented to the subject at a signal level of 55 dB HL through a B-70A BC transducer worn at the forehead position. Each subject was requested to write down the consonants as they heard them. Three conditions were utilised. In condition 1, CV exemplars were presented through air conduction (earphones) in order to assess the quality of the testing apparatus, including the CV exemplars, and to provide a reference for comparison to BC. In condition 2, these exemplars were presented through the BC transducer. Condition 3 involved two separate listening tasks in which CV exemplars were presented through the BC transducer and band-limited white noise was presented binaurally, correlated and uncorrelated, through earphones. The results indicated that speech discrimination with BC was excellent and equal to air-conduction consonant identification. The confusion matrices showed higher speech discrimination scores in the uncorrelated noise condition, revealing a binaural advantage for BC hearing. Distinctive feature identification was also greater for the uncorrelated noise condition

Eustachian tube dysfunction and wideband absorbance measurements at tympanometric peak pressure and 0 daPa

Background: Although wideband absorbance (WBA) provides important information about middle ear function, there is limited research on the use of WBA to evaluate eustachian tube dysfunction (ETD). To date, WBA obtained under pressurized condition has not been used to evaluate ETD. Purpose: The objective of the study was to compare WBA at 0 daPa and tympanometric peak pressure (TPP) conditions in healthy ears and ears with ETD. Research Design A cross-sectional study design was used. Study Sample A total of 102 healthy ears from 79 participants (mean age 5 10.0 yr) and 43 ears from 32 patients with ETD (mean age 5 16.0 yr) were included in this cross-sectional study. WBA was measured at 0 daPa (WBA) and TPP WBA at TPP (WBA). Data Collection and Analysis: WBA results were analyzed using descriptive statistics and t-tests with the Bonferroni correction. An analysis of variance with repeated measures was applied to the data. Results: WBA was significantly lower in the ETD group than in the control group. The WBA of the control group demonstrated a broad peak between 1.25 and 4 kHz, whereas the WBA of the ETD group had a peak between 2.5 and 4 kHz. WBA of the ETD group approached values close to that of the control group. In the control group, WBA was only 0.06 to 0.09 higher than WBA, whereas in the ETD group, WBA was 0.29 to 0.42 higher than WBA between 0.6 and 1.5 kHz. A differential pattern of WBA at TPP relative to 0 daPa was observed between ears with ETD and ears with otitis media with effusion (OME) and negative middle ear pressure (NMEP). Conclusions: Hence, a comparison of WBA and WBA can provide potentially useful diagnostic information, and hence can be used as an adjunct tool to evaluate ETD. This is important especially in young children or some adults who are unable to perform maneuvers such as Toynbee or Valsalva during ETD assessment. Further research is needed to verify the results using test performance measures to determine whether WBA and WBA can objectively determine the presence of ETD or OME with NMEP