Ear Canal Volume Research Articles

A Comparison of 226- and 1000-Hz Probe Tone Tympanometry With Myringotomy Findings in Infants.

This study aimed to verify the diagnostic value of tympanometry with 226- and 1000-Hz probe tones in infants by comparing tympanometry results with the gold standard of the middle ear state assessed by myringotomy. Furthermore, clinically useful predictors for false peaked tympanograms despite the presence of middle ear fluid should be identified. Pre-operative 226- and 1000-Hz tympanograms were retrospectively compared with intraoperative findings of the tympanic cavity after myringotomy in 111 infants (217 ears) aged ≤ 12 months. In addition to the shape of tympanograms, demographic and clinical characteristics, the results of other audiometric measurements, and the viscosity of middle ear fluid, if present, were evaluated in several subgroups. The sensitivity and specificity of 1000-Hz tympanometry for middle ear effusion (MEE) detection were 97%-98% and 71%-84%, respectively, whereas standard tympanometry with a 226-Hz probe tone achieved a poor sensitivity of 43%-61% and a specificity of 81%-97%. Younger age, low viscosity of the middle ear fluid, and female sex were associated with an increased risk of false peaked 226-Hz tympanograms despite MEE. Furthermore, larger equivalent outer ear canal volumes were linked to false peaked 226-Hz tympanograms. The comparison of myringotomy findings and 226- and 1000-Hz tympanometry confirms the superiority of high-frequency tympanometry in infants younger than 12 months. Although this study identified some vague predictors of potentially false peaked 226-Hz tympanograms, the assessment of the middle ear state by 226-Hz tympanometry remains unreliable in young infants.

Comparison of probe tone and click stimulus at 226 Hz frequency on acoustic ımmittance measurement in normal hearing adults: a cross-sectional study

ObjectivesAcoustic immittancemetry measurement is made using a probe tone or click stimulus at a frequency of 226 Hz, which is included in the audiological test battery. This study aims to compare tympanometric peak pressure (TPP), static acoustic admittance (Ytm), equivalent external ear canal volume (Vea) and tympanometric width (TW) values measured with probe tone and click stimulus at 226 Hz frequency.DesignMeasurements were made with a probe tone and click stimulus at frequency of 226 Hz in 60 ears of 30 adult individuals with normal hearing between the ages of 18–26. In the measurements TPP, Ytm, Vea and TW values were determined for both ears.ResultsIn two different tympanogram measurement results using 226 Hz click stimulus and 226 Hz probe tone were a statistically significant difference was found between Ytm, Vea and TW values in the left ear (p < 0.05) and a statistically significant difference was found between Ytm and Vea values in the right ear (p < 0.05). There was no significant difference between the right ear TPP and TW values, left ear TPP value (p > 0.05).ConclusıonThe current findings show that the comment of right and left ear tympanogram results should be evaluated according to two different measurement results using 226 Hz click stimulus and 226 Hz probe tone.

Role of Tympanometric Ear Canal Volumes in Determining Outcome of Myringoplasty in Chronic Suppurative Otitis Media Patients.

Middle ear aeration is a predictive indicator of myringoplasty's successful outcome and tympanometric ear canal volume is a novel investigation that can estimate the volume of middle ear cleft and mastoid air cells. Our aim of this study is to determine the role of tympanometric ear canal volume on myringoplasty outcome in Chronic Suppurative Otitis Media Patients. Prospective analysis involving 50 patients of CSOM was performed on patients undergoing myringoplasty from April 2022 to December 2023. Smokers, Patients with squamosal COM, Bilateral COM, Otitis Externa, and Revision surgery were excluded from the study. The successful outcome of surgery was defined as no tympanic membrane perforation on postoperative follow-up. Analysis was carried out using SPSS. V. 25 and P-value less than 0.05 was considered significant. A total of 50 patients were included in the study with a mean age of 24.4 ± 8.965 and male predominance. Overall graft uptake was 64%. Graft uptake had no significant statistical correlation with age, gender, type, location, or size of perforation. However, there is a significant effect of tympanometric ear canal volume of pathological ear and interaural tympanometric ear canal volume difference on graft uptake with p-values of 0.023 and 0.033 respectively. Tympanometric ear canal volume can predict middle ear aeration and the higher the interaural tympanometric canal difference more are the chances of successful graft uptake.

Mastoid Obliteration With Freeze‐Dried Bone Allograft in Canal Wall Down Tympanoplasty: Description of a Novel Technique and Case Report

Mastoid obliteration can be performed after canal wall down (CWD) mastoidectomy with various materials. Homologous bone tissue harvested from cadaver donor represents a feasible option with advantages. The purpose of the study is to describe the case of a patient diagnosed with middle ear cholesteatoma treated with mastoidectomy of the CWD and mastoid obliteration with homologous freeze‐dried corticocancellous bone particulate in the Cittadella Hospital Ear, Nose, Throat (ENT) unit. The preoperative characteristics of the patients, the procurement and processing of bone allografts, the surgical technique, and postsurgical outcomes are described. No perioperative and postoperative complications were observed, and no rejection or foreign body reactions occurred. The patient then underwent a seriated follow‐up. Audiometric tests showed an improvement in hearing levels. The volume of the neoexternal ear canal was 2.01 cm3. The case demonstrated clinical stability, substantial hearing recovery, and no need for specialist cleaning of the reformed external ear canal (EEC). The freeze‐dried bone tissue allograft, in the technical way we used, appears to be a viable option in mastoid obliteration because homologous bone is not affected by material shortage, has fast assimilation, and ensures a useful radiological examination scan, at a low cost.

Applying the reference values of real-ear-to-coupler-difference for deaf and hard-of-hearing children in Taiwan: Cautions and considerations.

Measurement of real-ear-to-coupler differentials (RECDs) is a critical part of the hearing aid (HA) verification process. This study examines the validity of reference RECD values preset by the HA analyzer, Audioscan RM500, for deaf-and-hard-of-hearing (DHH) children in Taiwan. RECD measurements were performed on 658 ears of DHH children. A linear mixed model was used to analyze the reference and measured RECD values. The findings revealed slight disparities between normative RECD values from North America and those observed in Taiwanese DHH children. While generally small (less than 5 dB), these differences imply potential challenges in achieving optimal HA fitting in specific scenarios. Therefore, we recommend individualized RECD/REM measurements for cases of poor auditory performance, certain frequency ranges, or notable variations in ear canal volume. From a clinical perspective, while broadly applicable, the use of North American RECD normative data in Taiwan requires cautious consideration of potential minor variations. This study contributes to current knowledge by affirming the use of a Western RECD database for Taiwanese DHH children. However, we underscore the ongoing importance of individualized HA fitting strategies, particularly for cases with stagnant intervention progress. While built-in RECD reference values can offer preliminary fitting guidance, especially in busy clinical settings, our study sheds light on the circumstances where caution is essential. Audiologists can efficiently allocate their time and effort by focusing on personalized RECD measurements for cases exhibiting suboptimal intervention outcomes, thereby effectively optimizing HA gain settings.

Development and Application of a Reference-Interval Approach to Tympanometric Norms Using U.S. Population Data for Ages 6-80+ Years.

United States national data for tympanometric measures from 16,614 ears included in the National Health and Nutrition Examination Survey for 2015-2016 and 2017-2020 were analyzed and described. Analyses were primarily descriptive and relied on distribution-free medians and cumulative distribution functions (CDFs). Differences between CDFs were examined using Cohen's h effect size. Results are presented for the age range 6-80+ years. A reference interval (RI) approach was pursued in which the interval from the 2.5th to the 95th percentile for healthy ears was specified for peak-compensated static admittance (Ytm+), tympanometric peak pressure, tympanometric width, and equivalent acoustic ear-canal volume (Vea+). Separate RIs were required for 6- to 13-year-olds compared to those 14-80+ years of age for all four tympanometric measures. For both age groups, a separate RI was warranted for each sex for Ytm+ and Vea+. For those 14-80+ years of age, a separate RI was also needed for non-Hispanic Asians for Ytm+. When these RIs were applied to the full data set, about 5%-10% of ears were found to be either below the lower limit or above the upper limit of the RI. Those ears outside the RI limits had about 5 dB higher low-frequency hearing thresholds than those within RI limits. Both Ytm+ and Vea+ were found to depend on body size. RIs for tympanometric measures from individuals with healthy ears were established, and when applied to the general U.S. population 6-80+ years of age, 5%-10% of ears fell outside the RIs depending on the measure.

High Frequency Tympanometry in Early Infancy and Its Effect on Oto Acoustic Emissions.

The present study was conducted to study the benefit of high frequency tympanometry (HFT) in detecting middle ear pathologies in infants. This study also aims to find the effect of middle ear diseases on absent otoacoustic emissions (OAE). Our study was a prospective study which included 123 healthy neonates below 1 month of age. The babies were referred for the new born hearing screening programme. They were subjected to DPOAE followed by tympanometry with a 1000z probe tone (HFT). The study was approved by the institutions ethical committee. "Present" OAE result was obtained for 202 ears, while "absent" OAE result was obtained for 44 ears. High frequency tympanometry was also performed on all the participants, where a normal tympanogram was obtained in 170 ears and 76 ears showed an abnormal tympanogram. The following parameters were studied: peak pressure, ear canal volume and compliance. Descriptive statistics were obtained for the same. Association of OAE with HFT was studied. Out of the 44 ears with refer OAE, 34 ears had an abnormal tympanogram and among 202 ears with a present OAE, 160 ears had a normal tympanometric peak indicating a sensitivity and specificity of 77.3% and 79.2% respectively. High frequency tympanometry not only helps in early detection of middle ear pathologies but also to find the effect of middle ear diseases on absent otoacoustic emissions.

Predicting children’s real-ear-to-coupler differences based on tympanometric data

Objective Paediatric hearing-aid verification relies on measures of output obtained from the ear canal or in a coupler with the child’s real-ear-to-coupler difference (RECD). Measured RECD cannot always be completed in children, leading to fitting inaccuracies. Audiologists often have tympanometry data that characterises the child’s ear-canal acoustics. The goal of this study was to determine if tympanometry can be used to improve predictions of measured RECD. Design A retrospective analysis of RECD and admittance, tympanometric peak pressure, and equivalent ear-canal volume from 226 Hz tympanometry collected as part of a longitudinal study of children with hearing loss were modelled with Bayesian hierarchical regression. Study sample Two-hundred sixty-six children with mild-to-severe hearing loss contributed data. Results Age-based average RECD models were within 3 dB of measured RECD values in 54% of cases with normal middle ear status and 50.6% of cases with abnormal middle ear status. Immittance-predicted RECD were within 3 dB in 69.6% of cases with normal middle ear status and 74.4% of cases with abnormal middle ear status. Conclusion Immittance-predicted RECD was more accurate than age-based average RECD, particularly in children with abnormal middle ear status. The findings suggest that 226 Hz tympanometry could be used clinically to improve predictions of measured RECD when it cannot be measured.

Could tympanometric volume be a useful tool to predict the success of type I tympanoplasty in simple chronic otitis media

Background: Middle ear aeration level is an important precursor of chronic otitis media (COM) and one predictive factor for tympanoplasty success. Tympanometry measures the volume of the external ear canal, middle ear cavity, aditus, and mastoid air cells in patients with tympanic membrane (TM) perforation. The aim of the study was to determine whether the pre-operative tympanometric volume and the interaural tympanometric volume differences in unilateral simple COM can predict the success of type I tympanoplasty. Methods: Retrospective analysis of type I tympanoplasties performed in adults between January 2017 and December 2020 in a tertiary hospital. Bilateral COM, revision surgery and tympanoplasty using cartilage grafts or associated with other procedures were excluded. Success was defined as no evidence of TM perforation on otoscopic examination and tympanogram, at least six months after surgery. Results: Sixty-one patients were evaluated. The mean age was 43 years old, and there was a female predominance (55.7%). The overall success rate was 77%. Location or size of perforation weren’t different among patients with and without surgical success. We found a statistically significant result (p=0.009) regarding interaural tympanometric volume differences, with a median of 2.7 ml (IQR 3.6) in the surgical success group and a median of 1.3 ml (IQR 1.26) in the recurrence group. 90.6% of patients with interaural tympanometric volume difference greater than 2 ml had successful surgery. Conclusions: A good aeration of middle ear, demonstrated by higher interaural tympanometric volume differences, can predict success of type I tympanoplasty.

Effect of Real-Ear Adjusted Stimuli on Vestibular Evoked Myogenic Potential Variability in Children and Young Adults.

There is large variability in cervical and ocular vestibular evoked myogenic potential (c- and oVEMP) amplitudes. One potential source of variability is differences in ear canal shape and size. Real ear-to-coupler difference (RECD) values are used to measure the acoustic environment of an individual's ear canal. RECD may be a useful measure to calibrate air conducted VEMP stimuli, which are elicited at high intensities and may put patients at risk of unsafe sound exposure. A recommendation for avoiding unsafe exposure is to use a 125 dB SPL stimulus for individuals with an equivalent ear canal volume (ECV) ≥ 0.9 mL and a 120 dB SPL stimulus for individuals with a smaller ECV. The purpose of this project was to determine if using a stimulus calibrated in the ear using RECD values significantly reduces intra-subject and inter-subject VEMP amplitude variability. We hypothesized that using a RECD-calibrated stimulus would significantly reduce inter-subject amplitude variability but not significantly reduce intra-subject variability. We further hypothesized that an RECD-adjusted VEMP stimulus would better protect against delivering unsafe sound exposure compared to the method of using ECV alone. Eleven children (4 to 9 years), 10 adolescents (10 to 18 years), and 10 young adults (20 to 40 years) with normal hearing, tympanometry, vestibular and neurological function participated. On all subjects, RECD was measured twice per ear to account for test-retest reliability. cVEMP and oVEMP were then recorded bilaterally with a 500 Hz tone burst at a traditional and an adjusted VEMP intensity level. The traditional intensity level was 125 dB SPL for individuals with ≥ 0.9 mL ECV and 120 dB SPL for individuals with ≤ 0.8 mL ECV. The adjusted intensity level was calculated by subtracting the average 500 Hz RECD measured values from the 500 Hz normative RECD value. This value was applied as a correction factor to a 125 dB SPL stimulus. Peak to peak amplitudes were recorded and used to calculate asymmetry ratios. Young children had significantly smaller ECVs compared to adolescents and young adults. Young children had larger RECDs; however, this was not significant in post hoc analyses. The method of calibration had no significant effect on intra-subject variability for cVEMP [ F (1, 27)= 0.996, p = 0.327] or oVEMP [ F (1, 25)= 1.679, p = 0.206]. The method of calibration also had no significant effect on inter-subject amplitude variability for cVEMP [ F (1, 120)= 0.721, p = 0.397] or oVEMP [ F (1, 120)= 0.447, p = 0.505]. Both methods of calibration adequately protected against unsafe exposure levels. However, there were subjects with ECVs ≥ 0.9 mL who approached unsafe exposure levels from the ECV-calibrated stimulus, suggesting there may be rare cases in which a 125 dB SPL stimulus is unsafe, even for patients with larger ECVs. The calibration method made no significant difference in intra- or inter-subject variability, indicating that the acoustic environment of the outer ear is not significantly contributing to VEMP amplitude variability. The RECD-adjusted stimulus is effective in protecting against unsafe exposure levels for two trials of both c- and oVEMPs. There may be instances where more than two trials of each test are required, which increases the effective stimulation level. Clinicians should be cautious when delivering VEMPs and not unnecessarily expose patients to unsafe levels of sound.

Chronic Noise Affects Middle Ear Resonance and Absorbance in Industrial Workers.

The effect of chronic noise on the middle ear is not fully known. This study aimed to evaluate the middle ear functions of metal workers exposed to chronic noise using wideband tympanometry. In this study, 62 male workers exposed to chronic noise and 30 healthy men were included. Workers exposed to chronic noise were divided into 2 groups according to their pure tone averages. Totally 30 workers (60 ears) with pure tone average less than 20 dB were included in group I, and 32 workers (64 ears) with pure tone average more than 20 dB were included in group II. All individuals were subjected to wideband tympanometry. Tympanometric peak pressure, equivalent ear canal volume, static acoustic admittance, resonance frequency, and absorbance ratios at peak pressure and ambient pressure values were analyzed. There was no difference between the groups in terms of traditional tympanometric parameters such as tympanometric peak pressure, equivalent ear canal volume, and static acoustic admittance (P >.05). Resonance frequency of workers exposed to chronic noise (group I and group II) was lower than the control group (P <.05). The absorbance ratios of workers exposed to chronic noise at approximately 4 kHz were lower in both peak pressures and ambient pressures (P <.05). Chronic noise does not only damage the inner ear but also causes changes in the middle ear structures. Wideband tympanometry can be used to detect minor auditory damage due to noise that cannot be detected by audiogram early. In this way, necessary measures can be taken in the early period before noise-induced hearing loss occurs.

Wideband Tympanometry: Normative Data for Young Iranian Adults

Introduction: The middle ear sound transmission features can impact acoustic sounds reaching the inner ear. Wideband tympanometry (WBT) or wideband acoustic immittance is an effective and desirable measurement of conductive conditions in newborns and adults and has appropriate sensitivity to distinguish different pathologies like otosclerosis from other middle ear conflicts. Recently, there has been an increased utilization of WBT, which highlights the importance of collecting population-based normative data as a necessary step in the standardization of this test, as well as for its clinical application. This study aimed to obtain normative data on WBT in the adult Iranian ethnic. Methods: There were 101 participants (202 ears) consisting of 53 males (57.4%) and 48 females (42.6%) in the age range of 19–29 years. The Titan WBT device (Interacoustics, Assens, Denmark) was used for WBT measurements. The broadband click was utilized as the probe tone between frequencies of 250 Hz and 8,000 Hz. All the participants underwent ear, nose, and throat assessments, pure-tone audiometry, and conventional tympanometry (226 Hz). Features like equivalent ear canal volume (V_eq), tympanometric peak pressure, gradient, resonance frequency (RF), energy absorbance (EA), and admittance (A_d) were tested. Results: In this cross-sectional study, 202 ears were tested for WBT. EA increased by frequency enhancement; at 1 kHz and 2 kHz the EA was the most prominent; at 2,519 Hz, it started decreasing, and at 8 kHz, there was a slight increase. There was also a significant difference in the V_eq and A_d between males and females. Studies have shown that the V_eq may vary between male and female subjects based on body size. Conclusion: In this study, normative data for the WBT were obtained from young Iranian adults with normal hearing ranges and middle ear conditions. We hope that this study and the resulting norm will provide a basis for increasing the use of WBT in Iranian diagnostic and clinical practices.

Effect of Aging on Tympanometric Findings in Indian Population

Abstract Introduction Presbycusis, or age-related hearing loss being a cumulative effect of aging on hearing, is a progressive and irreversible bilateral symmetrical sensorineural loss. In older individuals, one of the most important structures which undergo changes due to aging is the middle ear. There is a dearth of studies in Indian population regarding the tympanometric characteristics in older individuals. Thus, this study was taken up with an objective to report the different tympanometric characteristics in elderly individuals (aged above 50 years) who reported with ear- or hearing-related complaints to the Department of Audiology, All India Institute of Speech and Hearing, Mysore, Karnataka, India. Materials and Methods A register-based analysis was conducted where immittance tests were performed. Results There was no effect of age on static admittance, ear canal volume, and tympanometric peak pressure values. Also, there was no gender effect on tympanometric findings. Conclusion The result of the present study helps in understanding the different middle ear mechanisms in older adults.

Modeling individual noise-induced hearing loss risk with proxy measurements of external-ear amplification.

Significant variability in noise-induced hearing loss (NIHL) susceptibility suggests there are factors beyond sound level and duration of exposure that contribute to individual susceptibility. External-ear amplification (EEA) from external-ear structures varies significantly due to ear size and shape, potentially influencing NIHL susceptibility. This study tested the hypothesis that EEA can be predicted using non-technical proxy measurements including pinna height (cm), body height (m), and earcanal volume (cm3). 158 participants (4-78 years) completed otoscopy, tympanometry, pinna measurements, body height measurements, and two EEA measurements: (1) total real-ear unaided gain (REUG) of the open ear and (2) real-ear to coupler difference (RECD), representing unaided gain from the earcanal. Participants' individual noise doses were compared in hypothetical exposures. REUG ranged from 5 to 19 dBA and was correlated with pinna height. High-REUG participants were estimated to accrue noise doses at least 5 times higher than low-REUG participants. RECD ranged from 7 to 24 dBA and was correlated with earcanal volume and body height. The results support the hypothesis that EEA measurement could significantly improve estimation of an individual's position along the NIHL risk spectrum. Non-technical proxy measurements of EEA (pinna height, body height, earcanal volume) were statistically significant but yielded high variability in individual EEA prediction.

An Examination of Asymmetry in Adult Tympanometric Measures.

During audiologic evaluations, an examination of interaural asymmetry is commonly evaluated. To date, however, interaural differences for tympanometric indices have not been reported for adults. Without documented tympanometric right-left differences, one cannot determine if asymmetries are normal or are indicative of significant clinical asymmetries. The purpose of this study was to investigate interaural asymmetries in peak compensated static acoustic admittance (Ytm), equivalent ear canal volume (Vea), tympanometric peak pressure (TPP), and tympanometric width (TW) in normal adults. Descriptive, correlational, and inferential measures designs were employed. Participants were 188 otologically normal Caucasian young adults (i.e., 77 females and 111 males; M = 23.0 years, standard deviation [SD] = 2.7, range = 18-30 years). Ytm, Vea, TPP, and TW measures were obtained bilaterally from an admittance tympanogram using a 226 Hz probe tone. Separate two-factor mixed measures analysis of variance examined the effect of ear and sex for each tympanometric index. Correlation analyses examined the association between right and left ear indices. Interaural differences in tympanometric indices were examined with independent t-tests. Critical differences, for deciding if two tympanometric indices are different between ears, were computed from the standard deviations of the right-left ear difference for statistical confidence levels of 85, 90, 95, and 99%. The effect of ear was not statistically significant (p > 0.05) on any tympanometric index. Females had significantly lower Ytm and smaller Vea measures than males (p < 0.05). Correlations between all right and left tympanometric indices were positive and statistically significant (p < 0.05). There were no statistically significant differences in interaural differences for any of the tympanometric indices as a function of sex (p > 0.05). Critical differences, for confidence levels for 85% to 99% confidence ranged from ± 0.20-0.36 mmhos for Ytm, ± 0.23-0.41 cm3 for Vea, ± 11.1-19.8 daPa for TPP, and ± 27.2-48.7 daPa for TW. A clinician can use these critical differences to determine if tympanometric index interaural differences in ears of young normal Caucasian adults are statistically significant.

The effect of body mass index on traditional 226 Hz tympanometry and wideband tympanometry test results

Objectives: The aim of this study was to investigate the possible effects of body mass index (BMI) on traditional 226 Hz tympanometry and wideband tympanometry (WBT) to gain a better understanding of resonance frequency. Patients and Methods: A total of 158 ears of 79 volunteers (19 males, 60 females; mean age: 20.5 years; range, 18 to 27 years) who had normal hearing and normal otoscopic examination findings were included in the study between October 2019 and June 2020. By measuring the weight and height of the participants, their BMI values were classified into three groups: ≤18.5 kg/m2 (underweight), 18.5 to 24.9 kg/m2 (normal weight), and ≥25.0 kg/m2 (overweight). Tympanometric evaluations were conducted using the Interacoustics-Titan WBT. Results: The difference of ear canal volume (ECV) was significant between the two sexes (p&lt;0.05), while there was no significant difference in the tympanometric peak pressure, compliance, gradient, and resonance frequency between the sexes (p&gt;0.05). A significant difference was found in the ECV and resonance frequency among the three BMI groups (p&lt;0.05). Accordingly, as the BMI increased, the ECV increased and the resonance frequency decreased (p&lt;0.05). Conclusion: The BMI may affect ECV and resonance frequency values which should be considered during the examination.

Effects of Probe Tip Placement on Static Acoustic Admittance at the Plane of Measurement

Abstract Introduction: Tympanograms are recorded at the plane of the probe tip in the ear canal, consequently, this recording is called a tympanogarm in the plane of measurement and it includes both the acoustic admittance of the trapped volume of air between the probe tip and the tympanic membrane and the admittance of the middle ear system at the tympanic membrane. Materials and Methods: Eighty three participations (166 ears- 85 right ears, 81 left ears) were selected for the study. participants who had negative middle ear pressure greater than -50dapa and + 50 dapa and air and bone conduction thresholds gap of equal or more than 15 dB were excluded from the study. Data Analysis: Pearson correlation coefficient was carried out to see the relationship between residual ear canal volume (RECV) and acoustic admittance (Ya) and as well as for the tympanometric peak pressure (TPP). Results: Results shows there is strong positive correlation (r =0.854, P &lt;0.001) between the residual volume in the ear canal and admittance. Acoustic admittance were well correlated with the residual ear canal volume with coefficient of determination of r^2 = 0.793. In case of the middle ear pressure, it has been shown that there is positive moderate correlation (r = 0.679, P &lt; 0.001) between the middle ear pressure and acoustic admittance with coefficient of determination of r^2 = 0.473. Conclusion: The shift of probe tip placement in the ear canal and middle ear pressure variation changes the acoustic admittance value during immitance audiometry.

Normative ranges of tympanometric measurements in cats

Middle ear diseases are common in cats. The aim of this study was to determine the normative tympanometric data of cats. Tympanometry, which provides objective data in the examination of the middle ear in humans, can be used as a supplementary examination, especially in cats with middle ear diseases where the external ear canal is normal. In this study, 30 healthy ears belonging to 15 cats which were classified as ASA-I were determined and evaluated according to equivalent ear canal volume (Vea), static acoustic admittance [Ytm (compliance)], tympanometric peak pressure (TPP) and gradient values under general anesthesia. Tympanometric measurements obtained from right and left ears were 0.61 ± 0.12 ml and 0.60 ± 0.12 ml Vea, 0.31 ± 0.11 ml and 0.31 ± 0.11 ml Ytm, -11.2 ± 26.9 daPa and -14.9 ± 29.2 daPa TPP, 0.19 ± 0.11 ml and 0.24 ± 0.18 ml gradient respectively. Tympanometry as a supplementary examination is an easy to perform test in healthy cats with consistent results. It has the advantages of being completed in a short time, easy evaluation and providing information about middle ear without advanced imaging techniques. Results of this study represents the normative tympanometric measurements of cats which can be helpful distinguishing normal and abnormal conditions. Further studies needed to present exact values of standart tympanometric measurements and to introduce other variables like acustic refleks, wideband and multifrequency tympanometric results.

A Preliminary Analysis of Tympanometric Parameters in a Local Multiethnic Population.

Background: Tympanometry is a routine clinical test ordered at the Department of Otolaryngology, Ear, Nose and Throat (ENT) at Changi General Hospital (CGH). In combination with the pure tone audiogram, tympanograms aid in the diagnostic value of various middle ear disorders. However, its diagnostic value depends on the physician and audiologist’s accuracy of classifying and interpreting the tympanograms. Presently, Caucasian normative values are used in the classification of tympanograms, which could be inaccurate without population specific norms. Therefore, there is a need to understand ethnic differences in tympanometry parameters in order to usefully interpret the tympanogram. Thus far, there are no local studies on the differences in tympanometric parameters among multiethnic groups. Previous studies also had conflicting results on the effects of ethnicity with direct or indirect comparison only between two ethnic groups. To our knowledge, this is the first preliminary investigation on the effects of demographic and anthropometric measurements on tympanometric parameters. Materials and Methods: 90 patients’ medical charts were randomly selected and reviewed to extract demographic, anthropometric and clinical information. Tympanogram characteristics among ethnic groups were investigated using univariate and multivariate analyses. The mean ages of males and females in the study were 41.9 years ± 17.4 and 46.1 ± 19.2, respectively. Results: Gender significantly influenced ear canal volume (ECV). Chinese had marginally significant lower static admittance (SA) as compared to non-Chinese. There were, however, no effects of age or anthropometric measurements on tympanometric results. Conclusion: Further prospective large cohort analyses are warranted to expand this investigation to better elucidate differences observed in tympanometric parameters and establish population specific norms for appropriate and accurate tympanogram classifications.

Tympanometric interaural asymmetry in African-American school-aged children

ObjectivesThe purpose of this study was to investigate the tympanometric asymmetry in children. The determination of ear differences would be useful clinically in determining what qualifies as a significant asymmetry in tympanometric indices and hence middle ear dysfunction. MethodsFifty-five otologically normal school-aged African American children participated. Middle ear indices of peak compensated static acoustic admittance, equivalent ear canal volume, tympanometric peak pressure, and tympanometric width were examined. ResultsNo significant differences between right and left tympanometric indices were found (p > .05). Correlations between right and left tympanometric indices were positive and statistically significant (p < .05). Critical differences, for deciding if two tympanometry indices are different between ears, were computed from the standard deviations of the right-left ear difference for confidence levels of 85%–99%. ConclusionsCritical differences for tympanometric indices can be used by clinicians to assess if ear asymmetries are statistically significant.