Acoustic Immittance Measures Research Articles

Wideband acoustic immittance measurements in assessing crimping status following stapedotomy: A temporal bone study

Objective: To ascertain if wideband acoustic immitance (WAI) measurements are useful in assessing crimping status following stapedotomy. Design: WAI measurements were obtained using the Mimosa Acoustics HearID system. Wideband chirp sound stimuli and a set of tone stimuli for nine frequencies between 0.2 and 6 kHz were used at 60 dB SPL. Five sets of measurements were performed on each temporal bone: mobile stapes, stapes fixation and stapedotomy followed by insertion of a tightly crimped, a loosely crimped and an uncrimped prosthesis. Study sample: Eight fresh-frozen temporal bones were harvested from human cadaveric donors. Results: At lower frequencies, up to 1 kHz, stapes fixation decreased absorbance. Compared to the baseline absorbance, absorbance with stapes fixation dropped by 6 to 17% in absolute terms from the baseline value (p = 0.027). Absorbance was not affected in higher frequencies (p = 0.725). Stapedotomy changed the absorbance curve significantly compared to the normal condition with an increase of absolute absorbance values by 6 to 36% around 0.25–1 kHz (p-value <0.01). The crimping conditions did not differ from one another (p = 0.555). Conclusion: WAI is not useful in distinguishing between tightly crimped, loosely crimped and uncrimped stapes prostheses following stapedotomy.

Wideband reflectance in Down syndrome

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

Effects of Negative Middle Ear Pressure on Wideband Acoustic Immittance in Normal-Hearing Adults.

Wideband acoustic immittance (WAI) measurements are capable of quantifying middle ear performance over a wide range of frequencies relevant to human hearing. Static pressure in the middle ear cavity affects sound transmission to the cochlea, but few datasets exist to quantify the relationship between middle ear transmission and the static pressure. In this study, WAI measurements of normal ears are analyzed in both negative middle ear pressure (NMEP) and ambient middle ear pressure (AMEP) conditions, with a focus on the effects of NMEP in individual ears. Eight subjects with normal middle ear function were trained to induce consistent NMEPs, quantified by the tympanic peak pressure (TPP) and WAI. The effects of NMEP on the wideband power absorbance level are analyzed for individual ears. Complex (magnitude and phase) WAI quantities at the tympanic membrane (TM) are studied by removing the delay due to the residual ear canal (REC) volume between the probe tip and the TM. WAI results are then analyzed using a simplified classical model of the middle ear. For the 8 ears presented here, NMEP has the largest and most significant effect across ears from 0.8 to 1.9 kHz, resulting in reduced power absorbance by the middle ear and cochlea. On average, NMEP causes a decrease in the power absorbance level for low- to mid-frequencies, and a small increase above about 4 kHz. The effects of NMEP on WAI quantities, including the absorbance level and TM impedance, vary considerably across ears. The complex WAI at the TM and fitted model parameters show that NMEP causes a decrease in the aggregate compliance at the TM. Estimated REC delays show little to no dependence on NMEP. In agreement with previous results, these data show that the power absorbance level is most sensitive to NMEP around 1 kHz. The REC effect is removed from WAI measurements, allowing for direct estimation of complex WAI at the TM. These estimates show NMEP effects consistent with an increased stiffness in the middle ear, which could originate from the TM, tensor tympani, annular ligament, or other middle ear structures. Model results quantify this nonlinear, stiffness-related change in a systematic way, that is not dependent on averaging WAI results in frequency bands. Given the variability of pressure effects, likely related to intersubject variability at AMEP, TPP is not a strong predictor of change in WAI at the TM. More data and modeling will be needed to better quantify the relationship between NMEP, WAI, and middle ear transmission.

The Audiometric and Mechanical Effects of Partial Ossicular Discontinuity

Ossicular discontinuity may be complete, with no contact between the disconnected ends, or partial, where normal contact at an ossicular joint or along a continuous bony segment of an ossicle is replaced by soft tissue or simply by contact of opposing bones. Complete ossicular discontinuity typically results in an audiometric pattern of a large, flat conductive hearing loss. In contrast, in cases where otomicroscopy reveals a normal external ear canal and tympanic membrane, high-frequency conductive hearing loss has been proposed as an indicator of partial ossicular discontinuity. Nevertheless, the diagnostic utility of high-frequency conductive hearing loss has been limited due to gaps in previous research on the subject, and clinicians often assume that an audiogram showing high-frequency conductive hearing loss is flawed. This study aims to improve the diagnostic utility of high-frequency conductive hearing loss in cases of partial ossicular discontinuity by (1) making use of a control population against which to compare the audiometry of partial ossicular discontinuity patients and (2) examining the correlation between high-frequency conductive hearing loss and partial ossicular discontinuity under controlled experimental conditions on fresh cadaveric temporal bones. Furthermore, ear-canal measurements of umbo velocity and wideband acoustic immittance measurements were investigated to determine the usefulness regarding diagnosis of ossicular discontinuity. The authors analyzed audiograms from 66 patients with either form of surgically confirmed ossicular discontinuity and no confounding pathologies. The authors also analyzed umbo velocity (n = 29) and power reflectance (n = 12) measurements from a subset of these patients. Finally, the authors performed experiments on six fresh temporal bone specimens to study the differing mechanical effects of complete and partial discontinuity. The mechanical effects of these lesions were assessed via laser Doppler measurements of stapes velocity. In a subset of the specimen (n = 4), wideband acoustic immittance measurements were also collected. (1) Calculations comparing the air-bone gap (ABG) at high and low frequencies show that when high-frequency ABGs are larger than low-frequency ABGs, the surgeon usually reported soft-tissue bands at the point of discontinuity. However, in cases with larger low-frequency ABGs and flat ABGs across frequencies, some partial discontinuities as well as complete discontinuities were reported. (2) Analysis of umbo velocity and power reflectance (calculated from wideband acoustic immittance) in patients reveal no significant difference across frequencies between the two types of ossicular discontinuities. (3) Temporal bone experiments reveal that partial discontinuity results in a greater loss in stapes velocity at high frequencies when compared with low frequencies, whereas with complete discontinuity, large losses in stapes velocity occur at all frequencies. The clinical and experimental findings suggest that when encountering larger ABGs at high frequencies when compared with low frequencies, partial ossicular discontinuity should be considered in the differential diagnosis.

Potencial evocado auditivo de longa latência: diferenças na forma de contagem do estímulo raro

RESUMO Objetivo: identificar se existe diferença nos achados do Potencial Evocado Auditivo de Longa Latência em relação à latência e amplitude, em diferentes modos de contagem do estimulo raro, sendo contando mentalmente ou marcando no papel (sem memorizar). Métodos: esse estudo teve caráter prospectivo e transversal. A amostra foi composta por conveniência sendo constituída por 49 indivíduos, sendo 29 do gênero feminino e 20 do gênero masculino. Foram realizados os seguintes procedimentos: Inspeção Visual do Meato Acústico Externo, Audiometria Tonal Liminar, Medidas de Imitância Acústica e Potencial Evocado Auditivo de Longa Latência, o qual foi realizado duas vezes, uma após a outra, com os indivíduos atentando ao estímulo raro, começando sempre contando mentalmente e após marcando em um papel. Resultados: houve diferença estatisticamente significante entre as orelhas para as latências de P1, P2 e amplitude de N1 para o método de marcação no papel, da latência de N1 para o método de contagem mental dos estímulos raros, e da amplitude de P2 em ambos os métodos, porém com todos os valores dentro da faixa de normalidade. Além disso, a diferença estatisticamente significante também foi evidente na comparação entre os gêneros, sendo encontrados valores de latência maiores de P2 e N2 para o gênero masculino em ambos os métodos de contagem dos estímulos raros. A amplitude de P1, P2 e P3 foi menor no gênero masculino nas diferentes formas de contagem, sendo no P2 a diferença apenas no método contando mentalmente. Ao compararmos os métodos, houve diferença estatisticamente significante apenas para a latência de P2, a qual foi maior para o método marcando no papel. Conclusão: não houve diferença para as latências e amplitudes dos potenciais evocados auditivos de longa latência na comparação da contagem do estímulo raro (contando mentalmente e marcando no papel) para quase todos os potenciais, com exceção do potencial P2 em relação à latência e amplitude.

Acoustic Immittance Measures

One book, Acoustic Immittance Measures: Basic and Advanced Practice by Lisa L. Hunter and Navid Shahnaz, is reviewed in this issue. Tara Davis describes the text as an essential book for instructors, clinicians, and Au.D. students as it clearly describes contemporary scientific principles of middle ear immittance tests and techniques.

The audiological profile of adults with and without hypertension

OBJECTIVE:To determine whether there is any influence of systemic arterial hypertension on the peripheral auditory system.METHODS:This was a cross-sectional study that investigated 40 individuals between 30 and 50 years old, who were divided into groups with and without systemic arterial hypertension, using data from high-frequency audiometry, transient-evoked otoacoustic emissions and distortion-product otoacoustic emissions. The results were compared with those from groups of normal-hearing individuals, with and without systemic arterial hypertension, who underwent the pure-tone audiometry test. All individuals also underwent the following procedures: otoscopy, acoustic immittance measures, pure-tone audiometry at frequencies from 250 to 16000 Hz, transient-evoked otoacoustic emissions test and distortion-product otoacoustic emissions test.RESULTS:No statistically significant difference was observed between the groups with and without systemic arterial hypertension in either conventional or high-frequency audiometry. Regarding transient-evoked otoacoustic emissions, there was a trend toward statistical significance whereby the systemic arterial hypertension group showed lower results. Regarding distortion-product otoacoustic emissions, the systemic arterial hypertension group showed significantly lower results at the following frequencies: 1501, 2002, and 3003 Hz. A discriminant analysis indicated that the distortion-product otoacoustic emissions variables best distinguished individuals with and without systemic arterial hypertension.CONCLUSION:Data from this study suggest cochlear dysfunction in individuals with systemic arterial hypertension because their otoacoustic emission results were lower than those in the systemic arterial hypertension group.

Hearing profile and postural sensory integration deficits in Parkinson′s disease

Objective The objectives of this study were to evaluate auditory function and postural instability in Parkinson’s disease (PD) patients, and to correlate audiological findings and postural instability with the severity and duration of PD. Patients and methods The severity of motor symptoms and staging were ascertained with the Unified Parkinson’s Disease Rating Scale and the Hoehn and Yahr Scale, with identification of the side most affected by PD and the disease duration. Audiologic evaluation consisted of history taking, otoscopic examination, pure-tone audiometry, acoustic immittance measures, speech audiometry, and brainstem auditory-evoked potentials. Sensory Organization Test was also conducted. Of 55 PD patients, 31 were enrolled in this study, along with 31 healthy age-matched and sex-matched controls. Results and conclusion Our PD patients showed high-frequency, age-dependent unilateral or bilateral hearing loss, significant increase in wave V peak latency and I–V and III–V interpeak latencies, and significant decrease in composite score, vestibular score, and visual score and significant increase in preferential visual score in comparison with controls. All these findings were significantly correlated to disease severity and duration.

Potencial evocado auditivo de estado estável em crianças e adolescentes com perda auditiva neurossensorial de grau severo e profundo e descendente

Objetivo Verificar a correlação entre os limiares eletrofisiológicos obtidos no Potencial Evocado Auditivo de Estado Estável (PEAEE) e os limiares comportamentais obtidos com audiometria tonal liminar, em crianças e adolescentes com perda auditiva neurossensorial de grau severo e profundo e perda auditiva de configuração descendente. Métodos Foram avaliados 20 indivíduos, de ambos os gêneros, com idades entre 5 e 15 anos, distribuídos nos seguintes grupos: 10 indivíduos com perda auditiva neurossensorial descendente (GD) e 10 indivíduos com perda auditiva neurossensorial horizontal de grau severo e profundo (GS). Os indivíduos foram submetidos à audiometria tonal liminar, logoaudiometria, medidas de imitância acústica e ao potencial evocado auditivo de estado estável, nas frequências de 500 Hz, 1000 Hz, 2000 Hz e 4000 Hz. Resultados No grupo com perda descendente, a correlação foi de 0,68 a 0,94 e no grupo com perda auditiva de grau severo e profundo, a correlação foi de 0,59 a 0,86. As diferenças médias do limiar do PEAEE e do limiar da audiometria situaram-se entre 1,4 e 7,5 dB no grupo com perda descendente e entre -0,40 e -8,5 dB, no grupo com perda auditiva de grau severo e profundo. Conclusão Houve correlação positiva entre os limiares eletrofisiológicos e comportamentais nos grupos de crianças e adolescentes com perda auditiva neurossensorial horizontal de grau severo e profundo e descendente.

Characteristics of wideband acoustic immittance in patients with middle-ear dysfunction.

Wideband acoustic immittance (WAI) measurements are a relatively new class of aural acoustic tests that have shown promise as useful tools for evaluating middle-ear status. A growing body of work has described WAI for infants, children, and adults with normal middle-ear function, but a relatively limited number of studies have investigated the influence of specific middle-ear disorders on WAI. Although emerging WAI research data show promising results, additional measurements from ears of patients with a variety of middle-ear disorders are needed. The aims of the present study were to (1) obtain WAI data from patients with a variety of middle-ear conditions, (2) examine relationships between WAI data relative to standard audiometric tests, and (3) identify patterns or profiles in WAI data within and among patients with different middle-ear conditions. A descriptive study. Participants included 30 children and two adults with a variety of middle-ear disorders who were recruited from clinical audiology settings. Experimental ambient and tympanometric WAI data were gathered along with standard audiometric test data as part of clinical audiology appointments. Single-subject and small-group data sets for ears of patients with suspected otitis media with effusion (sOME), pressure equalization (PE) tubes, negative tympanometric peak pressure (TPP), tympanoplasty, and cerumen impaction were obtained. Qualitative analysis and descriptive statistics (means and percentiles) were used to characterize the data. Group mean absorbance for ears in the sOME group was reduced across the majority of frequencies; absorbance for ears with negative TPP was also reduced, although to a lesser degree. Absorbance patterns for ears with PE tubes show even greater differences because of the effects of the tube and open middle-ear cavity. WAI from ears with a tympanoplasty and cerumen impaction was suggestive of middle-ear dysfunction in the presence of normal single-frequency tympanometry. Percentile (5th, 50th, and 95th) plots for absorbance and other WAI quantities of admittance level, admittance phase, and equivalent ear-canal volume calculated for the sOME, negative TPP, and PE tube groups showed distinctive profiles that might be useful for discrimination of different middle-ear pathologies. Quantities from wideband tympanometry, including 250- and 1000-Hz single-frequency admittance tympanometric data were also derived. WAI measurements for some middle-ear conditions were consistent with patterns and profiles previously reported in the literature. WAI profiles for other middle-ear conditions, which had not been previously reported in the literature, were presented. Relationships between WAI data and results of standard audiometric tests were generally consistent with expectations. However, in some cases, WAI measurements were suggestive of middle-ear dysfunction despite normal 226-Hz admittance tympanometric findings.

Understanding the developmental course of the acoustic properties of the human outer and middle ear over the first 6 months of life by using a longitudinal analysis of power reflectance at ambient pressure.

As shown by tympanometric and wideband acoustic immittance (WAI) measures, developmental changes that occur in the middle ear and the external auditory canal can affect the mechano-acoustic properties of the middle ear system during the first 2 years of life. However, these observed differences and the specific course of maturation have not been fully investigated. The overall goal of the current study was to define the time course and rate at which functional maturation of the middle ear occurs in human infants through wideband acoustic immittance (WAI). It was also within the scope of this study to establish normative data to characterize acoustic properties of the normal middle ear in infants from birth to 6 mo of age. Newborns were tested longitudinally at 1-mo intervals up to 6 mo of age for a total of six visits. All babies passed transient evoked otoacoustic emission screening on each visit. Tympanograms and WAI were recorded, and the distributions of WAI patterns were analyzed as a function of age. WAI was measured across a wide range of frequencies from birth to 6 mos of age in a cohort of 31 infants. Test-retest differences for WAI were also evaluated. Thirty-one newborns were recruited. A repeated-measure analysis of variance was conducted to investigate whether the variations observed in power reflectance at ambient pressure across the six visits were statistically different. All significant findings were subject to Greenhouse-Geisser correction for repeated-measures sphericity and inflated type-I error. RESULTS showed that power reflectance increased (closer to 1) at low frequencies (<400 Hz) and decreased (closer to 0) at high frequencies (>2000 Hz) as a function of age. There was very little change in power reflectance from 600 to 1600 Hz across the first 6 mo of life. Most group changes that were observed were also consistently shown in longitudinal changes observed within individual subjects. The overall maturation of the middle ear can result in a lower reflectance at higher frequencies and a higher reflectance at lower frequencies. This could be explained by known changes in ear-canal and/or middle-ear structures across this time period, which could lead to changes in mass and resistance. An increase in volume in the middle-ear cavity, reduction of middle-ear debris, and overall decrease in resistive elements might be contributing to these changes. Significant differences were observed between each visit, which could warrant the use of age-specific norms when applying WAI data to infants less than 6 mo of age.

Effects of ear-canal static pressure on pure-tone thresholds and wideband acoustic immittance.

Wideband acoustic immittance (WAI) measures provide information about middle-ear function across the traditional audiometric frequency range from 0.25 to 8.0 kHz. Recent studies have found that WAI is effective in predicting the presence of conductive hearing loss (CHL). It is not known whether WAI can accurately estimate the degree of threshold shift caused by CHL. The purpose of the present study was to evaluate the relationship between changes in pure-tone threshold and changes in wideband absorbance and acoustic conductance levels induced by positive and negative ear-canal static pressure. Twenty young adult subjects with normal hearing and a negative history of middle-ear disorders participated in the study. Experimental pure-tone thresholds at 0.5 and 2.0 kHz were estimated by using a three-interval, three-alternative forced-choice adaptive psychometric procedure under three conditions: ambient ear-canal pressure, +200 daPa static pressure, and -200 daPa static pressure. Wideband absorbance and conductance were obtained in the same subjects by using a Welch Allyn prototype diagnostic middle ear analyzer. Changes in pure-tone threshold from the ambient pressure condition to the static pressure condition were evaluated by using a paired-samples t test and Pearson product-moment correlation. Wideband middle-ear absorbance and conductance at ambient pressure in this study were consistent with published data in adults with normal hearing. The mean change in threshold at 0.5 and 2.0 kHz with +200 daPa or -200 daPa ear-canal static pressure was similar to the mean change in absorbance and conductance levels in the same conditions. However, there was one statistically significant difference between the shift in pure-tone threshold and the change in conductance level for the +200 daPa pressure condition for 2.0 kHz, with the change in threshold being 1.5 dB greater than the change in conductance level (t = 2.39, p = 0.03). In contrast to the good performance of WAI measures in predicting mean threshold shifts caused by ear-canal pressure, the shifts in WAI were not correlated with threshold shifts. Thus WAI was not well suited to predict individual threshold changes caused by ear-canal static pressure. For the conditions of this study, results suggest that mean change in absorbance or conductance level caused by ear-canal static pressure of +200 daPa or -200 daPa provides a good estimate of the change in pure-tone threshold in the same conditions. However, individual threshold change was not accurately predicted by the change in absorbance or conductance level.

Sources of variability in wideband energy reflectance measurements in adults.

Wideband acoustic immittance measurements of the middle ear, such as wideband energy reflectance (ER), can provide information about how the middle ear functions across the traditional audiometric frequency range. These measurements are being investigated as a new means of evaluating conductive hearing disorders, and studies have been reported on a number of middle-ear disorders. However, the normative database for wideband ER is still being developed, and more information is needed about sources of test variability. The purpose of the present study was to evaluate sources of variability in wideband ER measurements at baseline and across annual tests for up to 5 yr in subjects with normal hearing. The main group consisted of 112 subjects (187 ears), 24 females and 88 males, with normal hearing and normal 0.226-kHz admittance tympanometry. An additional 24 adults with abnormal 0.226-kHz tympanometry provided baseline comparison data. A longitudinal design was used in obtaining annual measurements of audiometry, tympanometry, and wideband ER at ambient pressure in adults. Clinical audiometry and tympanometry data and 1/3-octave wideband ER measurements were obtained at baseline and annually for up to four additional tests. Descriptive statistics and t-tests were used to explore differences in 1/3-octave baseline ER measures in terms of subject age, test ear, sex, and clinical tympanometry. Longitudinal mixed-effects linear regression models at 1.0, 2.0, and 4.0 kHz were used to examine the different sources of variance affecting ER over time. There were small but statistically significant mean differences in ER for baseline measurements as a function of ear, sex, and age. Compared with these results, data for 29 ears with abnormal 0.226-kHz tympanometry differed from mean normal data across a broad frequency range by as much as 20%. ER varied as a function of peak compensated static acoustic admittance (Ytm) for measures at 1.0 kHz but was unrelated to Ytm at 2.0 and 4.0 kHz. ER also varied as a function of the test ear, with significantly higher ER on the left at 1.0 and 2.0 kHz, but was not significantly related to the test ear at 4.0 kHz. The standard deviation for test-retest variability was about 0.1 at each frequency, which is consistent with previous studies. Mean wideband ER at baseline showed small but significant differences related to sex, ear, and age. ER was significantly related to Ytm at 1.0 kHz in the longitudinal data but not at 2.0 or 4.0 kHz and to the test ear at 1.0 and 2.0 kHz but not at 4.0 kHz. When evaluated at ambient pressure, ER for ears with negative middle-ear pressure was similar to that of ears with abnormally low Ytm. Therefore it might be necessary to evaluate wideband acoustic immittance compensated for middle-ear pressure by using tympanometry to obtain an effective differential diagnosis of middle-ear disorders in adults.

Wideband absorbance in Australian Aboriginal and Caucasian neonates.

Despite the high prevalence of otitis media in Australian Aboriginal infants and children, the conductive mechanism of the outer and middle ear of Aboriginal neonates remains unclear. Differences in characteristics of the conductive pathway (outer and middle ear) between Aboriginal and Caucasian neonates have not been systematically investigated by using wideband acoustic immittance measures. The objective of this study was to compare wideband absorbance (WBA) in Australian Aboriginal and Caucasian neonates who passed or failed a screening test battery containing high-frequency tympanometry and distortion product otoacoustic emissions (DPOAEs). A cross-sectional study design was used. The mean WBA as a function of frequency was compared between Aboriginal and non-Aboriginal neonates who passed or failed the test battery. A total of 59 ears from 32 Aboriginal neonates (mean age, 51.9 h; standard deviation [SD], 18.2 h; range, 22-86 h) and 281 ears from 158 Caucasian neonates (mean age, 42.4 h; SD, 23.0 h; range, 8.1-152 h) who passed or failed 1000-Hz tympanometry and DPOAEs were included in the study. WBA results were analyzed by using descriptive statistics and t tests with Bonferroni adjustment. An analysis of variance with repeated measures was applied to the data. Aboriginal and Caucasian neonates had almost identical pass rates of 61%, as determined by the test battery. Despite the apparently equal pass rates, the mean WBA of Aboriginal neonates who passed the test battery was significantly lower than that of their Caucasian counterparts at frequencies between 0.4 and 2 kHz. The mean WBA of Aboriginal neonates who failed the test battery was significantly lower than that of their Caucasian counterparts who also failed the test battery at frequencies between 1.5 and 3 kHz. Both Aboriginal and Caucasian neonates who failed the test battery had significantly lower WBA values than their counterparts who passed the test battery. This study provided convincing evidence that Aboriginal neonates had significantly lower WBA values than their Caucasian counterparts, although both groups had equal pass rates, as determined by the test battery. Although the two ethnic groups showed significant differences in WBA, the factors contributing to such differences remain undetermined. Further research is warranted to determine the factors that might account for the difference in WBA between the two ethnic groups.

Pediatric Applications of Wideband Acoustic Immittance Measures

Pediatric Applications of Wideband Acoustic Immittance Measures

Audiological Abnormalities in Patients With Turner Syndrome

The purpose of this study was to evaluate the prevalence, type, and severity of hearing impairment in patients with Turner syndrome (TS) and to determine whether these characteristics correlated with the patient karyotype and age. This was a cross-sectional prospective study. The participants underwent an audiological evaluation, including pure-tone audiometry, speech audiometry, and acoustic immittance measures. This study included 52 patients with TS (mean age = 19 years, SD = 6 years, range = 7-37 years). The majority of these patients had a decline in pure-tone thresholds at 8000 Hz, and most also had mild to moderate hearing loss. Most patients had normal tympanometric results. More than 80% of patients had acoustic reflexes present at 500, 1000, and 2000 Hz frequencies bilaterally, but less than 50% of the patients displayed an acoustic reflex at 4000 Hz bilaterally. The hearing loss was more prevalent in patients with a 45,X karyotype and isochromosomes as compared to patients with mosaicism. The results showed that TS patients with a 45,X karyotype and isochromosomes with loss of the p-arm of the X chromosome had a greater risk of developing hearing loss than patients with mosaicism. There was a linear association between hearing loss and age in these patients.

Exposição a níveis de pressão sonora em sala de aula, imitanciometria e teste SSW em escolares de 3º e 4º ano do ensino fundamental

OBJETIVO: investigar os efeitos dos níveis de pressão sonora elevados em sala de aula e das alterações imitanciométricas sobre as habilidades auditivas de crianças em fase inicial de letramento. MÉTODOS: estudo quantitativo e exploratório. Medições acústicas por meio de dosímetro; inspeção visual do conduto auditivo externo; audiometria tonal e vocal; imitanciometria. Os resultados das mensurações acústicas realizadas por meio de dosímetro em quatro escolas de Santa Maria - RS, dividiu a amostra de 87 crianças do 3º e 4º ano do ensino fundamental, na faixa etária de oito a dez anos em dois grupos - Grupo 1 / não expostos e Grupo 2 / expostos a níveis maiores que 80dB(A). A amostra também foi separada em 38 crianças sem alterações imitanciométricas e 49 com alterações, avaliadas em suas habilidades auditivas pelo teste dicótico de Dissílabos Alternados - SSW. RESULTADOS: o G1 apresentou melhores resultados na DC e EC em ambas às condições imitanciométricas, sem evidenciar diferença estatística. Foi constatada maior quantidade de acertos para a OE; a média do total de acertos evidenciou desempenhos semelhantes entre os grupos; o G1 apresentou melhores resultados na decodificação fonêmica, porém piores resultados nos subperfis codificação e organização. CONCLUSÕES: o presente estudo demonstrou que níveis de pressão sonora elevados em sala de aula não interferem nas habilidades auditivas testadas por meio do SSW, de crianças em processo de aprendizagem.

Avaliação audiológica na ataxia espinocerebelar

To describe the audiological and electrophysiological results in patients with spinocerebellar ataxia (SCA). Retrospective and cross-sectional studies were performed. Forty-three patients were assessed using the following procedures: anamnesis and otolaryngologic exam, pure tone audiometry, acoustic immittance measures and brainstem auditory evoked potential (BAEP). Patients showed gait abnormality (83.7%), speech disorder (48.8%), dizziness (41.8%) and dysphagia (39.5%). Hearing loss was referred in 27.9% of the cases; in the audiometric exams, 14 patients (32.5%) presented disorders; in SCA 3, 33.3%; in SCA 2, 12.5%; in SCA 4, 100.0%; in SCA 6, 100.0%; in SCA 7, 100.0%; in SCA 10, 50.0%; and in undetermined SCA, 21.4%. In BAEP, 20 patients (46.5%) were abnormal, being 58.3% in SCA 3, 62.5% in SCA 2, 100.0% in SCA 6, 100.0% in SCA 7, 66.7% in SCA 10 and 14.2% in undetermined SCA. While in acoustic immittance, 19 patients (44.1%) presented disorders, being 50.0% in SCA 3, 50.0% in SCA 2, 100.0% in SCA 4, 100.0% in SCA 6, 100.0% in SCA 7, 33.3% in SCA 10 and 28.5% in undetermined SCA. The most evident abnormalities in the audiological evaluation were the predominance of the down-sloping audiometric configuration beginning at 4 kHz bilaterally and the bilateral absence of acoustic reflex at the frequencies of 3 and 4 kHz. In the electrophysiological evaluation, 50% of the patients showed abnormalities with prevalence of an increase of the latency of waves I, II and V and of the interval in the interpeaks I-III, I-V and III-V.

Pediatric Applications of Wideband Acoustic Immittance Measures

Wideband acoustic immittance (WAI) measures have potential capability to improve newborn hearing screening outcomes and middle ear diagnosis for infants and children. To fully capitalize on these immittance measures for pediatric hearing care, developmental and pathologic effects need to be fully understood. Published literature on wideband immittance (reflectance, absorbance, tympanometry, and acoustic reflexes) is reviewed in this article to determine pathologic effects in newborns, infants, and children relative to standard audiologic tests such as otoacoustic emissions (OAEs), standard tympanometry, air and bone conduction auditory brainstem response, and otoscopy. Infants and children with surgically confirmed otitis media with effusion have lower absorbance in the mid-frequency range (1 to 3 kHz) for the affected ear(s). Newborns that do not pass OAE screening at birth also have lower absorbance for frequencies from 1 to 3 kHz, suggesting that nonpass results are frequently associated with middle ear issues at birth. In Newborn Hearing Screening Programs, WAI may help to interpret hearing screening results. Conclusions are limited by the fact that the true status of the middle ear and cochlea are not known for newborns and infants in studies that use OAE or tympanometry as the reference standard. Likelihood ratios for reflectance against surgery gold standards range from diagnostically suggestive to informative. Although some of the results are promising, limited evidence and methodological considerations restrict the conclusions that can be drawn regarding the diagnostic accuracy of WAI technologies in infants and children. Additional investigations using stronger gold standard comparisons are needed to determine which tools can most accurately predict middle ear status in the pediatric population.

Wideband Acoustic Immittance Measurements of the Middle Ear

This supplement focuses on some of the most recent acoustic measurements within the occluded, human external auditory meatus (EAM). The goal of this introduction is to provide an overview of basic and clinical EAM measurements that evolved in the 20th century and some relations between these measurements and wideband acoustic absorbance. The authors review some of the major efforts that have been used to evaluate the condition of the human, adult middle ear transmission system, the middle ear cavity, and the function of the Eustachian tube. They have grouped most of this work under the rubric of “acoustic immittance.” A historical perspective helps one appreciate that the measurement of wideband acoustic absorbance is not a totally new procedure. Rather, it is the latest enhancement to aural acoustic-immittance measurements. An enhancement that can expand one's ability to characterize middle ear function and effects of ear disease on that function. It also allows clinicians evaluate middle ear function for frequencies whose wavelength is shorter than the length of the EAM.