Multifrequency Tympanometry Research Articles

The Effect of Rheumatoid Arthritis on Middle and Inner Ear Functions.

To investigate the middle and inner ear functions, and efferent auditory systems in patients with rheumatoid arthritis (RA). Thirty-five RA patients and 40 control subjects participated in the study. Pure-tone audiometry, high-frequency audiometry, multifrequency tympanometry, transient evoked otoacoustic emissions, and contralateral suppression tests were administered to all participants. Pure-tone hearing thresholds of RA patients were significantly higher at all frequencies except for 2000 Hz, 14,000 Hz, and 16,000 Hz in the right ear and 16,000 Hz in the left ear (p<0.05). Resonance frequency values of RA patients were statistically significantly lower than those of the control group (p<0.001). Emission amplitudes obtained with contralateral acoustic stimulation were significantly lower at 1400 Hz frequency in both groups than without contralateral acoustic stimulation (p<0.05). While contralateral suppression was observed at all frequencies in the control group, no suppression occurred at 2800 Hz and 4000 Hz in RA patients. The results obtained in this study demonstrated the presence of hearing dysfunction in patients with RA. When a patient is diagnosed with RA, an audiological evaluation should be made, and the patient should be informed about the possibility of audiological involvement.

Can Multifrequency Tympanometry Be Used in the Diagnosis of Meniere's Disease? A Systematic Review and Meta-Analysis.

(1) Background: Ménière's disease (MD) is a disease of the inner ear, presenting with episodes of vertigo, hearing loss, and tinnitus.The aim of this study is to examine the role of multifrequency tympanometry (MFT) in the diagnosis of MD. (2) Methods: A systematic review of MEDLINE (via PubMed), Scopus, Google Scholar, and the Cochrane Library was performed, aligned with the PRISMA guidelines. Only studies that directly compare ears affected by Ménière's disease with unaffected or control ears were included. Random-effects model meta-analyses were performed. (3) Results: Seven prospective case-control studies reported a total of 899 ears, 282 of which were affected by Ménière's disease (affected ears-AE), 197 unaffected ears in patients with MD (UE), and 420 control ears (CE) in healthy controls. No statistically significant differences between the groups were observed regarding resonant frequency (RF). The pure tone audiometry average of the lower frequencies (PTA basic) was significantly greater in affected ears when compared with unaffected ears. The conductance tympanogram at 2 kHz revealed a statistically significantly greater G width of 2 kHz in the affected ears when compared to both unaffected and control ears, while control ears had a statistically significant lesser G width of 2 kHz compared to both the other two groups. (4) Conclusions: MFT, and specifically G width at 2 kHz, could be an important tool in the diagnosis of MD.

The Diagnostic Value of Multifrequency Tympanometry in Patients with Ménière’s Disease: A Prospective Analysis

Introduction: Diagnosing Ménière’s disease (MD) by its characteristics such as episodes of vertigo, fluctuating hearing loss, and tinnitus with aural fullness remains challenging. Available tests evaluating the presence of endolymphatic hydrops (EH) are often expensive or time assuming. An in-office quick and simple non-invasive diagnostic test is multifrequency tympanometry (MFT). It can measure conductance at 2 kHz probe tones, which was demonstrated to reflect variations in cochlear pressure. Previous studies investigating MFT as a diagnostic test for MD showed conflicting outcomes possibly biased by their retrospective design. Methods: We prospectively collected MFT results (Y width) in patients with dizziness and compared MFT test results in affected (group 1) and unaffected (group 2) ears of 37 MD subjects and in control ears of 33 non-MD subjects (group 3). Results: The mean value of the Y width in affected ears was 315.6 ± 70.2 daPa compared to 292.3 ± 98.6 daPa in unaffected ears in MD subjects and 259.4. ± 60.6 daPa in the non-MD group. A positive test result (i.e., a Y width of 235 daPa or more) was found in 35 ears in the MD group, 21 times involving the affected ear and 14 times involving the unaffected ear, compared to 16 in the non-MD group. No significant differences between the three groups could be demonstrated (p > 0.05). We found a sensitivity of 58.3% and specificity of 66.3% for detecting EH in an affected ear in MD subjects. Conclusion: There is a trend towards increased conductance tympanometry in affected ears. However, we noticed a high false positive rate of MFT and do not support standardized use of MFT as an additional diagnostic tool for detecting EH in MD patients. A negative test result on the contrary is unlikely related to EH.

Assessment of Middle Ear Function Using Wideband Acoustic Immittance: Current Practices and Future Prospects.

Acoustic immittance tests have been used in clinical practice for the assessment of middle ear function since the 1960s. In the following decades, single-frequency admittance tympanometry has become a staple test of middle ear function in routine audiological practice, and to a lesser extent, multifrequency tympanometry. The acoustic properties of middle ear are best understood through physiological assays of its gain spectrum, tested over a wide range of frequencies; i.e., the middle ear transfer function. Yet, clinical assessment with multi-frequency tympanometry has been limited to frequencies below 2000 Hz. Thanks to advances in probe characterization techniques, measurements of impedance at frequencies beyond 2,000 Hz have become possible. These advances ushered in a new frontier for acoustic immittance research and paved the way for a host of new wideband acoustic immittance (WAI) measures that promised improved clinical assessments through better approximation of the transfer function and acoustic mechanics of the middle ear. Translational and clinical research further developed and refined WAI for clinical use through establishment of clinical norms, emergence of data in ears with conductive disorders, and demonstrated improvements in test accuracy of WAI over single-frequency tympanometry for a variety of clinical populations. Together with emergence of commercially available systems, since the mid-2000s, these developments signal the emergence of WAI testing as a standard audiological tool for the assessment of the middle-ear function. Although clinical adoption of this promising diagnostic technology is lagging, widespread adoption is expected with further refinement of WAI measures, and as updated clinical practice guidelines recommend the incorporation of WAI testing into clinical test batteries (e.g., JCIH, 2019).[1]

Fundamental Concepts for Assessment and Interpretation of Wideband Acoustic Immittance Measurements.

Assessment of middle ear impedance using noninvasive electroacoustic measurements has undergone successive developments since its first clinical application in the 1940s, and gained widespread adoption since the 1970s in the form of 226-Hz tympanometry, and applications in multifrequency tympanometry. More recently, wideband acoustic immittance (WAI) is allowing unprecedented assessments of the middle ear acoustic mechanics thanks to the ability to record responses over a wide range of frequencies. The purpose of this article is to present fundamental concepts for the assessment and interpretation of wideband measures, including a review of acoustic impedance and its relation to the mass, stiffness, and resistance components of the middle ear. Additionally, an understanding of the middle ear transfer function reveals the relationship between impedance and middle-ear gain as a function of frequency. Wideband power absorbance, a WAI measure, quantifies the efficiency of sound conduction through the middle ear over a wide range of frequencies, and can serve as an analogous clinical measure to the transfer function. The interpretation of absorbance measures in ears with or without a conductive condition using absorbance measured at ambient pressure and pressurized conditions (wideband tympanometry) is described using clinical case examples. This article serves as an introduction to the fundamental principles of WAI measurements.

Gender and ear differences in multi-frequency tympanometry

Objective: The aim of the study was to find the effects of gender and ear difference of multi-frequency tympanometry in Indian young adult population.Method: A total of 30 individuals include 15 males and females with normal hearing were taken for the study. Resonant frequency and F45 were determined in both ears of all individuals and compared.Result: The test results showed that the mean resonant frequency and mean F45 have no significant difference in left and right ears. Females have slightly better RF and F45 than males.

The Effect of Postmenopausal Osteoporosis on Middle Ear Resonance Frequency.

Background: The effect of postmenopausal osteoporosis on the middle ear mechano-acoustic system is unknown. The aim of this study is to investigate whether or not middle ear resonance frequency is affected in females with postmenopausal osteoporosis.Methods:The study included postmenopausal women aged 45-60 years, separated into 2 groups as females with postmenopausal osteoporosis and healthy postmenopausal females (control group). A detailed anamnesis was taken from all subjects and then the ear, nose, and throat examinations were done followed by pure tone audiometry, tympanometry, and multifrequency tympanometry tests. The groups were compared in respect of pure tone average, bone conduction threshold, RF, static admittance, and tympanometric peak pressure values.Results: The mean age of the patients was 59.2 ± 4.53 years (range, 48-65 years) in the postmenopausal osteoporosis group and 57.11 ± 4.27 years (range, 48-65 years) in the control group (P > .05). The mean resonance frequency values for the postmenopausal osteoporosis and control group were 954.41 ± 127.47 and 935.29 ± 126.39 Hz (P > .05 ). The mean static admittance values for the postmenopausal osteoporosis and control group were 0.82 ± 0.33 and 0.85 ± 0.3 mmho, and mean tympanometric peak pressure values were −7.35 ± 18.52 and −6.94 ± 19.52 daPa (P > .05 for both static admittance and tympanometric peak pressure). The mean pure tone averagevalues for the postmenopausal osteoporosis and control group were 20.96 ± 6.82 and 15.60 ± 7.81 dB, and mean bone conduction threshold values were 17.57 ± 6.03 and 12.10 ± 6.52 dB (P < .05 for both pure tone average and bone conduction threshold).Conclusions: The results showed that the middle ear resonance frequency values were not affected in postmenopausal osteoporosis patients, but there was seen to be greater sensorineural hearing loss in females with postmenopausal osteoporosis compared to healthy postmenopausal females.

Middle-Ear Resonance Frequency and Eustachian Tube Function in Players of Wind Instruments

Introduction: The effect of the continuous forced expiration action of players of wind instruments to produce sound, on the eustachian tube functions and the middle-ear resonance frequency (RF), has not been investigated in the literature to date. The aim of this study is to evaluate eustachian tube functions and the middle-ear RF of players of wind instruments. Methods: In this prospective case-control clinical study, a study group of 28 players of wind instruments in the orchestra (28 participants, 56 ears) and a control group of 34 volunteers (34 participants, 68 ears) were included. The eustachian function of wind instrument players in a symphony orchestra was measured using an automatic eustachian tube function test in acoustic tympanometry and the RF of the middle ear was determined in multifrequency tympanometry. Results: There was a statistically significant difference among the musicians, especially in players of woodwind instruments, in terms of dysfunction of the eustachian tubes (p = 0.048). In the musicians, the pre- and postperformance RF mean values for all ears were 925 and 1,020 Hz, respectively, and these were significantly different (p = 0.004). Conclusion: This is the first study to uses multifrequency tympanometry to examine the middle-ear RF and eustachian tube function of wind instrument musicians in an orchestra. Eustachian tube dysfunction was found to be more prominent and a higher RF of the middle ear was seen after a performance, especially in players of wood wind instruments. However, the effect of these on the professional performance of players of wind instruments should be investigated in future work.

Audiovestibular Dysfunction in Patients with Fibromyalgia Syndrome.

Objectives: Fibromyalgia syndrome is a disorder of widespread pain with unknown etiology. These patients frequently suffer from otologic complaints. This study aims to analyze the audiovestibular functions in patients with fibromyalgia syndrome.Methods: The study included 33 fibromyalgia patients and 33 healthy volunteers. All the study subjects underwent audiological assessment, multifrequency tympanometry, transient otoacoustic emission, and ocular and cervical vestibular-evoked myogenic potentials tests.Results: Pure-tone hearing thresholds of right and left ears were found to be decreased in fibromyalgia patients compared to controls (P < 0.05). Middle ear resonance frequency values were significantly decreased in patients with fibromyalgia syndrome compared to controls (P < .05). The values for signal-to-noise ratios were higher in controls than in the FMS patients. The difference was significant for 1000, 2000, and 4000 Hz (P > .005). Cervical vestibular-evoked myogenic potential waves were obtained in all controls, but could not be obtained in 5 right ears and 4 left ears of the fibromyalgia patients (P < .05). Also, ocular vestibular-evoked myogenic potentials were obtained in all controls, but could not be obtained in 7 right ears and 10 left ears of the patients with fibromyalgia syndrome (P < .05).Conclusion: Our findings support the presence of audiovestibular dysfunction in patients with fibromyalgia. Further research that focuses on the pathogenesis of these dysfunctions is required.

Rising Resonance Frequency Is the Sole Sign of Early Middle Ear Disease in Children With Adenoid Hypertrophy.

The present study seeks to estimate the potential of multifrequency tympanometry in the diagnosis of primal otologic disorder in children with adenoid hypertrophy (AH). Prospective observational study. Tertiary pediatric institution. One hundred thirty-one children presenting consecutively at the otolaryngology clinic were divided on the basis of AH into 98 patients and 33 controls. Middle ear status was assessed using pneumatic otoscopy, standard, and wide band tympanometry. Tympanogram type/intratympanic pressure, and resonance frequency (RF) were correlated with each other as well as with a set of clinical parameters. Receiver operating characteristic analysis was employed to reveal the diagnostic value of RF. Mean RF declined in chronic otitis media with effusion by 43.25% (p < 0.001). In our entire cohort, children with AH under the age of 7 years presented with a relative risk = 2.43 of producing "B" tympanogram (p = 0.016) than their older peers. In patients' ears with normal, type "A," tympanogram, RF was the sole tympanometric marker of AH, being elevated by 28.26% in mean value (p = 0.010). On receiver operating characteristic analysis of RF's discriminating capability, the area under the curve was equal to 0.647 (p = 0.010). The optimal cut-off value of RF was set at 899 Hz. AH may induce middle ear stiffening, as RF's increase indicates. Wide band tympanometry output could be a warning sign of ongoing compliance reduction to the sound transmission apparatus, at a time point when physical examination and 226 Hz tympanometry are still unremarkable.

Multi-frequency tympanometry

Multi-frequency tympanometry

Effects of Glycerol Test on Resonance Frequency in Patients with Ménière’s Disease

Objective: To evaluate resonance frequency (RF) values via dehydration effects in the inner ear caused by the glycerol test, which is used as a diagnostic method for Ménière’s disease (MD). Methods: Twenty adult patients with unilateral MD were included in the study. Before, and then at 1, 2, and 3 h after administration of glycerol (1 g/kg), pure-tone hearing levels (125–8,000 kHz) and multifrequency tympanometry tests were performed. As a control, the RF values of the ears of 25 healthy subjects (i.e., 50 ears) were compared to the affected and unaffected ears in the 20 MD patients. Results: There was a significant difference between the RF values of affected and healthy ears before glycerol administration (p = 0.047). The RF values before and after glycerol administration into affected ears were compared. The average RF values decreased significantly from 748.0 ± 402.1 to 808.0 ± 410.1 Hz at 1 h after glycerol intake, and this value increased during the subsequent hours. There were no statistically significant differences between the pure-tone levels before and 1 h after glycerol administration, but a significant decrease was observed at 3 h. Conclusion: We suggest that MD has different inner-ear dynamics and normal RF values when compared to healthy ears. Furthermore, decreased inner ear pressure causes reduction of the mass effect and a stiffening of the annular ligament. We conclude that pre- and post-RF tests should be added to the test battery for diagnosis of MD.

Stapedotomy with incus vibroplasty – A novel surgical solution of advanced otosclerosis and its place among existing therapeutic modalities – Hungarian single institutional experiences

ObjectiveTo delineate the advantages and steps of stapedotomy with incus vibroplasty, to assess the safety and efficacy of this method via the authors’ experiences, and to overview the literature regarding other surgical options in advanced otosclerosis determining the place of stapedotomy with incus vibroplasty in the therapeutic range. MethodsFour patients were enrolled in the study presenting severe mixed hearing loss of at least one side on pure tone audiometry. Based on complementary audiological examinations including stapedial reflex test and multifrequency tympanometry, all cases were suspected as advanced otosclerosis. Stapedotomy with incus vibroplasty – the combination of laser stapedotomy and simultaneous Vibrant Soundbridge implantation – was performed in each patient. Preoperative pure tone average, speech recognition thresholds and word recognition scores were compared to one-year postoperative free-field values with the implant switched on focusing on functional gain. ResultsAmong 4 participants (3 females, 1 male) the mean age (SD) was 66 years (35). In three cases Nitinol, in one case NitiBond piston was inserted. One-year postoperative free-field functional gains were 30 dB, 34 dB, 42 dB and 51 dB, respectively. One-year postoperative free-field speech recognition thresholds were 45 dB, 45 dB, 49 dB and 50 dB, respectively, while word recognition scores were 70%, 70%, 70% and 75%, respectively. ConclusionPostoperative results in our serie regarding pure tone average and word recognition score proved to be better than those found in the literature. Stapedotomy with incus vibroplasty – through sufficient air-bone gap closure and simultaneous sensorineural component management – seems to be a promising surgical solution in advanced otosclerosis, requiring further investigation.

Changes in middle ear transmission characteristics secondary to altered bone remodelling.

Alteration in the process of bone remodelling or increase in the number of osteoclasts cells as it occurs in osteoporosis and osteopenia are likely to affect the middle ear bones in the same way it affects the skeletal bones. Whether these micro-structural changes occurring at the level of the middle ear secondary to altered bone remodelling cause any significant impairment in its functioning is not explored. Thus, the present study aimed at assessing the different aspects of middle ear functioning in individuals with reduced BMD. The study included 25 normal, 39 osteopenic and 40 osteoporotic participants. The participants underwent pure-tone audiometry, otoscopic examination, conventional immittance evaluation using a 226Hz probe tone, multi-component and multi-frequency tympanometry and acoustic reflex threshold testing. None of the participants had any current or previous history of middle ear effusion. A significantly higher proportion of participants in the clinical group had hearing loss compared to the normal group. The clinical group participants also had reduced middle ear resonance frequency, elevated static compliance values and elevated or absent acoustic reflexes compared to the normal participants. There was no difference among the three groups for the proportion of participants having conductive hearing loss. There is a detrimental impact of reduction in bone mineral density on middle ear transmission characteristics which may go unnoticed initially. Treatment of osteoporosis may potentially mitigate hearing loss from middle ear fractures due to reduced bone mineral density. Absence of significant air-bone gap with the presence of reduced middle ear resonance frequency may be early signs of reduced BMD.

Normalisation values for the resonant frequency of the middle ear in rats

p { margin-bottom: 0.08in; direction: ltr; color: rgb(0, 0, 0); }p.western { font-family: Cambria, serif; font-size: 12pt; }p.cjk { font-family: MS Mincho, ＭＳ 明朝, monospace; font-size: 12pt; }p.ctl { font-family: Cambria, serif; font-size: 12pt; } Objective : In earlier studies, the resonant frequency (RF) of the middle ear has been investigated in a number of different animals. However, no study has so far specifically addressed the measurement of RF in rats. With this in mind, in our study, multifrequency tympanometry (MFT) was performed on rats and RF value measurements were taken. The aim was to ascertain the normal values for rats used in our university experiments and to provide guidance for further research to be undertaken in this area. Materials and Methods: For the study, 16 male and 16 female adult Sprague Downey rats (32 animals, 64 ears) aged 10 months old and in healthy condition were used. MFT at 226Hz frequency and above was performed on all the rats after they had been anaesthetised. In the first instance tympanograms were recorded using the 226Hz probe tone, following which MFT measurements were performed. RF values for the middle ear were determined in the range 200-2000Hz. Results: For male rats, the mean RF value was 426.56 (± 193.01 Hz), whilst for female rats the mean was 496.88 (± 132.55) Hz. When the values obtained for the male and female rats were compared, no statistically significant difference was observed between the two groups (p=0.061). Accordingly, the mean RF value for the rats as a whole (obtained for 64 ears) was calculated to be 461.7 (± 168.02) Hz. Conclusion: In this research, RF values for the middle ear of rats has been demonstrated to be measurable. However, further research is needed into the relationship between RF and the characteristics of the middle ear in rats.

Diagnosis and following up of Ménière’s disease using multifrequency tympanometry—Cutoff values and temporal changes in measurements

ObjectiveThis study aimed to verify cutoff values for G width (the width of bimodal peaks for the waveform obtained when measuring conductance at 2000Hz) in Japanese individuals diagnosed with Ménière’s disease (MD) using multifrequency tympanometry (MFT) and to determine the relationship between the G width and ability to hear low-pitched sounds using measurements over time. MethodsThe study included 51 patients with clinically diagnosed MD, who had not undergone endolymphatic sac surgery, but had no other known ear disease (57 ears in patients aged 22–80 years were affected, and 45 ears in patients aged 18–83 years were unaffected; mean age: 53.3±16.9 years). We also enlisted 80 healthy controls with no prior history of ear disease (160 ears, aged 22–76 years, mean age: 40.8±15.7 years). MFT was used to measure the bimodal peak width of the waveform obtained when measuring conductance at resonance frequency of 2000Hz. For patients who had G width measured several times over multiple outpatient visits, we used initial test data to analyze cutoff values. In nine cases with four or more measurements over time, we evaluated a possible correlation between G width and the sum of the hearing threshold for three low-pitched frequencies (125Hz, 250Hz, and 500Hz). We used Student’s t-test to determine significance. ResultsThe both ears in the MD patients had a G width wider than the distribution in the control group. There was a significant difference between G width in the control group and in affected ears with MD (p=0.00026) and there was also a significant difference between G width in the control group and in unaffected ears of MD patients (p=0.0056). The cutoff value set with a specificity of 95% was 200daPa, with a sensitivity of 35.1% and specificity of 95.6%. The cutoff value set with a sensitivity of 50% was 140daPa, with sensitivity of 50.9% and specificity of 78.8%. There was no significant difference between resonance frequency of ears in the control group and ears with MD (p=0.41). In nine cases with four or more measurements over time, a case showed a statistically significant positive correlation between the G width and hearing ability threshold for low-pitched sounds (125Hz, 250Hz, and 500Hz) (p=0.03), while an another case showed a tendency toward a positive correlation, which was not statistically significant (p=0.08). Further, there were cases that did not show significant differences in the present study, but might have shown a negative correlation if the number of measurements had been increased. ConclusionMeasurement of G width using MFT may have accuracy as the traditional endolymphatic hydrops test. MFT is non-invasive, causes little discomfort for patients, requires little time to perform, and can be performed by paramedics. MFT was shown to be useful in screening for MD and it is effective in diagnosing MD to measure the change over time of G width using MFT.

Advances in auditory function research of Meniere disease

Meniere disease is a unique, progressive disease of the inner ear. The complex manifestation presents diagnostic challenges. It is difficult to diagnose due to the absence of typical presentations especially in the early stages. The cochlear symptoms often present prior to vertigo and tend to be ignored. Therefore, focusing on the cochlear symptoms and functions may provide information for early diagnosis and may protect the patients from acquiring a hearing disability. This review focused on the pure-tone audiometry, glycerin test, distortion product otoacoustic emissions, auditory brainstem response, electrocochleogram, multifrequency tympanometry, and speech audiometry, which hopefully could emphasize the importance of the symptomatic and functional findings of cochlear, and be helpful in diagnosis for Meniere disease.

Middle Ear Function Measures From Single Component Tympanometry to Wideband Acoustic Immittance

This paper highlights collective research findings about middle ear measures using standard single- and multi-frequency tympanometry measures and wideband acoustic immittance (WAI) measurements, including wideband energy reflectance and wideband absorbance tympanometry. The paper also provides a review of normative and pathological findings with WAI measures. Current research suggests that WAI measures provide faster and more accurate assessment of middle ear status than standard tympanometry measures in both infants and adults. WAI measures assess the middle ear across a wide range of frequencies, which help with differential diagnoses of middle ear disorders. With this new advance in middle ear measures and promising research findings, audiologists are encouraged to incorporate WAI measures in the basic audiologic test battery as a screening and a diagnostic tool for middle ear disorders and for newborn hearing screening.

Middle Ear Resonance Frequency in Pilots and Pilot Candidates.

Barotrauma is a frequent problem in aviation medicine. Eustachian tube dysfunction plays a critical role in the pathogenesis of barotrauma. Function of the Eustachian tube can be indirectly assessed by multifrequency tympanometry, which provides valuable information about the resistance and permeability of the middle ear in a wide frequency range. The aim of this study was to research whether multifrequency tympanometry could be used for assessing middle ear impairments in pilots. There were 140 pilots and pilot candidates between the ages of 20-55 with normal otoscopic examination who were evaluated by audiological test batteries. Body mass index values, flight hours, audiometric pure tone thresholds, tympanometry and multifrequency tympanometry test results were noted. There was statistically significant decrease in the multifrequency tympanometry measurements of the left and right ears of the pilots with 200-3000 flight hours compared to pilot candidates, and similarly, the pilots with 3000-10,000 flight hours compared to pilot candidates. Multifrequency tympanometry values changed between pilot candidates and pilots. However, the values of multifrequency tympanometry did not change due to flight hours. This test battery should not be used for follow up of pilots in the clinic. Tuncer MM, Babakurban ST, Aydin E. Middle ear resonance frequency in pilots and pilot candidates. Aerosp Med Hum Perform. 2016; 87(10):876-881.

Decrease in Middle Ear Resonance Frequency During Pregnancy.

Many physiological changes occur during pregnancy. The aim of the study was to reveal whether there is a change in middle ear resonance frequency during pregnancy. A prospective case-control study was designed at a tertiary referral center. The study included 46 pregnant women at the third trimester (27-40 weeks) and 43 nonpregnant voluntary women. All the study subjects underwent pure-tone audiometry and multifrequency tympanometry. Pure-tone hearing levels at frequencies of 250 to 8000 Hz and resonance frequency values were compared between pregnant and nonpregnant women. Impact of age, side of the tested ear, and weight gained in pregnancy on resonance frequency were evaluated. Air conduction threshold values at frequencies of 250 Hz and 500 Hz were significantly higher in pregnant women than in the control group (P<0.001). Middle ear resonance frequency values of both ears in pregnant women were found to be significantly lower than those in control group (P<0.001). There was no statistically significant relation of middle ear resonance frequency values to age or side of the tested ear in both groups (P>0.05). A negative correlation between weight gained in pregnancy and middle ear resonance frequency values was determined for the left ear (correlation coefficient for left ears: –0.348, P=0.018). The results of this study suggest that resonance frequency may be decreased during the pregnancy. More comprehensive studies in which many pregnant women followed regularly before and after pregnancy are needed to have more certain links.