Differential effects of mass-loading the eardrum and stiffening the middle ear on wideband absorbance.

The current work investigated the effects of mass-loading the eardrum on wideband absorbance in humans. A non-invasive approach to mass-loading the eardrum was utilized in which water was placed on the eardrum via ear canal access. The mass-loaded absorbance was compared to absorbance measured for two alternative middle ear states: normal and stiffened. To stiffen the ear, subjects pressurized the middle ear through either exsufflation or insufflation concurrent with Eustachian tube opening. Mass-loading the eardrum was hypothesized to reduce high-frequency absorbance, whereas pressurizing the middle ear was hypothesized to reduce low- to mid-frequency absorbance. Discriminant linear analysis classification was performed to evaluate the utility of absorbance in differentiating between conditions. Water on the eardrum reduced absorbance over the 0.7- to 6-kHz frequency range and increased absorbance at frequencies below approximately 0.5 kHz; these changes approximated the pattern of changes reported in both hearing thresholds and stapes motion upon mass-loading the eardrum. Pressurizing the middle ear reduced the absorbance over the 0.125- to 4-kHz frequency range. Several classification models based on the absorbance in two- or three-frequency bands had accuracy exceeding 88%.

Balloon Eustachian tuboplasty in a professional Navy SEAL diver: case report.

Middle ear barotrauma due to dilatory Eustachian tube dysfunction (ETD) is probably the most common medical disorder related to diving. Moreover, ETD makes divers prone to other diving-related accidents, including inner ear barotrauma and alternobaric vertigo. Until the development of Eustachian tube balloon dilation no diving-compatible surgical options existed to effectively and safely prevent recurrence. We present a case of an Israeli Navy SEAL diver who dives in extreme strenuous combat-related closed-circuit rebreather (CCR) dives. Due to repeated middle ear barotrauma, the patient underwent Eustachian tube balloon dilation of the affected side. Following surgery, the patient returned to both CCR and scuba dives but still suffered from middle ear symptoms and repeated barotrauma hence was eventually disqualified from further combat diving.

Proposal of a new scoring system for equalization problems during freediving.

OBJECTIVE: Scuba diving and freediving are popular activities around the world, and their growth has increased the frequency of related pathology. A good ability to equalize is of paramount importance for diving. This is especially true for freediving, during which dive time is limited to just one breath. Even though equalization disorders are quite common in divers, a scoring system does not exist to date. In this paper we propose a new scoring system for equalization problems of freedivers: the EP score, shorthand for "equalization problems." METHODS: We administered the EP score assessment to 40 Italian freediving spearfishermen who were divided in two groups: Group A comprised 20 freedivers complaining of equalization problems and multiple barotraumas but totally asymptomatic in their everyday lives. These individuals had already received medical treatment and nasal surgery without improvement and then had undergone Eustachian tube balloon dilation. Group B comprised 20 healthy freedivers without any history of equalization disorders. We performed a statistical analysis to evaluate the reliability of this scoring system and to evaluate its usefulness in diagnosis and follow-up. RESULTS: Our data show substantial statistical differences between healthy freedivers and freedivers complaining of equalization disorders (Z-Score = -5.396 at p ⟨ 0.05); data do not show any statistical difference between healthy freedivers and patients successfully treated by Eustachian tube balloon dilation (U-value = 152.5 and Z-Score= -1.271 at p ⟨ 0.05). CONCLUSION: The EP score assessment seems to be a reliable tool to quantify equalization disorders during freediving and to evaluate how the difficulty varies over time and after treatment. Since equalization disorders could be present in different populations, the EP score assessment could be applicable to a wider group.

Proof of concept study using a modified Politzer inflation device as a rescue modality for treating Eustachian tube dysfunction during hyperbaric oxygen treatment in a multiplace (Class A) chamber.

Introduction: Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are the most common adverse effects of hyperbaric oxygen (HBO2) treatments. Patients practice equalization maneuvers to prevent ETD and MEB prior to hyperbaric exposure. Some patients are still unable to equalize middle ear pressure. This ETD results in undesirable consequences, including barotrauma, treatment with medications or surgical myringotomy with tube placement and interruption of HBO2. When additional medications and myringotomy are employed, they are associated with additional complications. Methods: A device known as the Ear Popper® has been reported to reduce complications from serous otitis media and reduce the need for surgical interventions (myringotomy). Patients unable to equalize middle ear pressure during initial compression in the hyperbaric chamber were allowed to use the device for rescue. All hyperbaric treatments were compressed using a United States Navy TT9, or a 45-fsw hyperbaric treatment schedule. Patients with persistent ETD and the inability to equalize middle ear pressure were given the Ear Popper upon consideration of terminating their treatment. Results: The Ear Popper allowed all patients to successfully equalize middle ear pressure and complete their treatments. Conclusion: This study substantiates the use of this device to assist in allowing pressurization of the middle ear space in patients otherwise unable to achieve equalization of middle ear pressure during HBO2 treatment in a multiplace chamber.

Underwater nasal decongestant use: a novel approach to middle ear equalization.

Middle ear barotrauma is the most common diving-related injury. It is estimated to occur in more than 50% of experienced divers. Although divers learn how to effectively equalize their ears with various maneuvers, airway congestion may impede the ability to equalize the middle ear space via the Eustachian tube. In this case, one may have to avoid diving or abort a dive due to inability to descend. If difficulty with middle ear equalization occurs during the bottom phase of the dive, which may transpire during a multilevel cave or wreck dive, a diver may need to descend before he can exit the water. In this case, it is imperative that the middle ear can be equalized, or one risks middle ear barotrauma, tympanic membrane rupture, possible accrual of decompression and dwindling breathing gas reserves. A 46-year-old diver encountered difficulty with equalization during a cave dive and was able to administer oxymetazoline intranasally to facilitate middle ear equalization. Although effective for this individual,this maneuver is not without risks, which include disorientation, loss of buoyancy, coughing, sneezing, laryngospasm, and a theoretical increased susceptibility to CNS oxygen toxicity.

Diagnostic accuracy of tubomanometry R value in detecting the Eustachian tube pressure equalizing function.

Tubomanometry is a relatively novel Eustachian tube (ET) function testing method. A number of recent studies have utilized the R value of Tubomanometry as the main objective measure in reporting their outcome in balloon dilation of ET. There is, however, a lack of evidence concerning the reliability or validity of Tubomanometry measurements. The objectives of this study are to determine the accuracy of Tubomanometry for detecting ET opening as compared to tympanometry and determine its usefulness as a measure of ET function. Healthy subjects between ages 8 and 76 years with an intact tympanic membrane and no middle ear (ME) effusion were prospectively tested. Primary outcomes were the ET opening as determined by the Tubomanometry R value and the increase in ME pressure with tympanometry-measured in relation to a swallow at a nasopharyngeal pressure of 300 daPa. The accuracy of the tubomanometry R value for identifying a successful ET opening was made in reference to the change of ME pressure. A total of 280 measurements were available from 258 ears in 137 subjects. The presence of tubomanometry R value showed high sensitivity of detecting ET opening for the criteria of >5 daPa ME pressure increase (187/202) but low specificity for detecting ET non-opening (34/78). The R value criterion described in the original manuscripts on Tubomanometry is sensitive but not specific for ET opening. The need for validation of the tubomanometry test obviates its use as the main objective outcome measure for the balloon dilation of ET procedure.

Reliability of Eustachian tube function measurements in a hypobaric and hyperbaric pressure chamber.

OBJECTIVES: Measurement of the Eustachian tube (ET) function is a challenge. The demand for a precise and meaningful diagnostic tool increases-especially because more and more operative therapies are being offered without objective evidence. The measurement of the ET function by continuous impedance recording in a pressure chamber is an established method, although the reliability of the measurements is still unclear. METHODS: Twenty-five participants (50 ears) were exposed to phases of compression and decompression in a hypo- and hyperbaric pressure chamber. The ET function reflecting parameters-ET opening pressure (ETOP), ET opening duration (ETOD) and ET opening frequency (ETOF)-were determined under exactly the same preconditions three times in a row. The intraclass correlation coefficient (ICC) and Bland and Altman plot were used to assess test-retest reliability. RESULTS: ICCs revealed a high correlation for ETOP and ETOF in phases of decompression (passive equalisation) as well as ETOD and ETOP in phases of compression (active induced equalisation). Very high correlation could be shown for ETOD in decompression and ETOF in compression phases. The Bland and Altman graphs could show that measurements provide results within a 95 % confidence interval in compression and decompression phases. CONCLUSIONS: We conclude that measurements in a pressure chamber are a very valuable tool in terms of estimating the ET opening and closing function. Measurements show some variance comparing participants, but provide reliable results within a 95 % confidence interval in retest. This study is the basis for enabling efficacy measurements of ET treatment modalities.

ICE on the road to auditory sensitivity reduction and sound localization in the frog.

Frogs and toads are capable of producing calls at potentially damaging levels that exceed 110 dB SPL at 50 cm. Most frog species have internally coupled ears (ICE) in which the tympanic membranes (TyMs) communicate directly via the large, permanently open Eustachian tubes, resulting in an inherently directional asymmetrical pressure-difference receiver. One active mechanism for auditory sensitivity reduction involves the pressure increase during vocalization that distends the TyM, reducing its low-frequency airborne sound sensitivity. Moreover, if sounds generated by the vocal folds arrive at both surfaces of the TyM with nearly equal amplitudes and phases, the net motion of the eardrum would be greatly attenuated. Both of these processes appear to reduce the motion of the frog's TyM during vocalizations. The implications of ICE in amphibians with respect to sound localizations are discussed, and the particularly interesting case of frogs that use ultrasound for communication yet exhibit exquisitely small localization jump errors is brought to light.

On the origin of ear clicks during deglutition or pressure equalization.

To explore the origin of clicking sounds in the ear during deglutition or other pharyngeal movements, which are interpreted differently in the literature. Experimental study at a tertiary referral centre. Acoustic phenomena during a forced opening test of the Eustachian tube (ET) were studied in a temporal bone model. Additionally, in vivo experiments were carried out in healthy volunteers for ruling out movements of the ossicular chain or the drumhead as potential causes of clicks. Thus, acoustic recordings were performed parallel to stapedius or tensor reflex measurements or pneumatic video endoscopies of the tympanic membrane. Obviously the acoustic signals (clicks) appear when the tube opens, which could be visualized and acoustically recorded during forced opening tests in temporal bone experiments. Middle ear muscle contractions with movements of the tympanic membrane did not cause any click events. Together with the results of a previous paper (9) we interpret the clicks as disruptions of fluid or mucus films covering the mucosa during the ET opening. The final goal of our studies is to use such clicks as indicators of ET openings in a new tube function test, which has to be elaborated.

The endoscopic study of human middle ear mucociliary transport.

The mucociliary clearance (MCC) is an important defence mechanism of the middle ear. The mucociliary transport (MCT) is a part of MCC. We measured the duration of MCT and visualised its routes in middle ears of 31 patients (mean age 45 years; range 7-61 years; SD 11.6) with intact tympanic membrane, with ventilated middle ears and without a history of prolonged otitis media. The transition time of indigo carmine dye from the promontory mucosa to the middle ear orifice of the Eustachian tube (ET) was observed with a rigid 30°, 1.7-mm-diameter tympanoscope. The dye took an average of 7 min (range 4.5-15 min; SD 3.4; median 4.5) to reach the ET orifice in 25 (81 %) patients. Three main ciliary pathways were detected: (1) below and parallel to the tensor tympani muscle; (2) downwards, anterior to the round window, and then ascending to the ET; and (3) straight across the promontory.

Time for Eustachian Tube Function Recovery in Children with Cleft Palate after the 2-Flap Palatoplasty with Intravelarveloplasty.

Objective: Evaluate the clinical outcomes regarding the time needed for Eustachian tube recovery and evaluate associated factors for the recovery in children with cleft palate undergoing primary 2-flap palatoplasty with intravelarveloplasty at Srinagarind Hospital. Material and Method: This was a retrospective descriptive study of 82 consecutive non-syndromic cleft palate patients with/without cleft lip, who underwent primary palatoplasty at Srinagarind Hospital between January 2007 and December 2010. Demographic data were collected including sex, cleft type, age of palatoplasty, operating surgeon, type of tympanogram, oronasal fistula, ventilation tube insertion, age of ventilation tube insertion, and number of ventilation tube insertion. Results: Forty-five boys and 37 girls were included in the study for a total sample of 82 patients. The majority of cleft types was Veau IIIb (37.8%), followed by Veau IV (21.95%), Veau IIIa (20.73%), Veau I (9.76%), and Veau II (9.76%). Mean age of palatoplasty was 11.4 months (range, 9-23). There were three plastic surgeons and plastic surgery residents. The average time for Eustachian tube recovery was 37.5 months. Oronasal fistula was 15.9%. Ventilation tube insertion was 58.5% (one time: 40.2%, two and three times: 18.3%). Average age of ventilation tube insertion was 16 months (range, 9-64). There was no statistically significant difference in sex, age of palatoplasty, operating surgeon, ventilation tube insertion, or number of ventilation tube insertions in Eustacian tube recovery, but there was a statistically significant difference in cleft type, oronasal fistula, and mean age for ventilation tube insertion in Eustachian tube recovery. Conclusion: The median recovery time for Eustachian tube function after primary 2-flap palatoplasty with intravelarveloplasty at Srinagarind Hospital was 37.5 months. Eustachian tube recovery was associated with severity of cleft types, oronasal fistula formation, and age of ventilation tube insertion.

Optical coherence tomography for the diagnosis and evaluation of human otitis media.

We report the application of optical coherence tomography (OCT) to the diagnosis and evaluation of otitis media (OM). Whereas conventional diagnostic modalities for OM, including standard and pneumatic otoscopy, are limited to visualizing the surface of the tympanic membrane (TM), OCT effectively reveals the depth-resolved microstructure below the TM with very high spatial resolution, with the potential advantage of its use for diagnosing different types of OM. We examined the use of 840-nm spectral domain-OCT (SD-OCT) clinically, using normal ears and ears with the adhesive and effusion types of OM. Specific features were identified in two-dimensional OCT images of abnormal TMs, compared to images of healthy TMs. Analysis of the A-scan (axial depth scan) identified unique patterns of constituents within the effusions. The OCT images could not only be used to construct a database for the diagnosis and classification of OM but OCT might also represent an upgrade over current otoscopy techniques.

Handheld tympanometer measurements in conscious dogs for the evaluation of the middle ear and auditory tube.

BACKGROUND: Otitis externa is frequently accompanied by otitis media, yet it can be difficult to evaluate the tympanum, middle ear and auditory tube without the use of advanced radiographic imaging. HYPOTHESIS/OBJECTIVES: The objective was to develop techniques for tympanometry testing in conscious dogs and to present normative data for clinical use of this equipment to enable assessment of the tympanum, middle ear and auditory tube. ANIMALS: Sixteen hounds (14 female) from a school teaching colony. METHODS: Dogs were gently restrained in a standing position. After cleaning of the ear canal, a tympanometer probe tip extension was placed in the vertical canal and automated testing performed using a handheld device. Both ears were tested in all dogs. RESULTS: Acceptable recordings were obtained from both ears of 13 dogs, from one ear in each of two dogs and from neither ear of one dog, resulting in data from 28 of 32 (88%) ears. Otoscopic examination confirmed the absence of inflammation or any other obvious explanation for the noncompliant dogs. No significant differences were seen between ears for any measure. Normative data are reported for peak compliance, peak compliance pressure, gradient and ear canal volume. CONCLUSIONS AND CLINICAL IMPORTANCE: Tympanograms can be recorded in conscious dogs to assist in the evaluation of the middle ear structures.

Is there a difference between active opening of the Eustachian tube in a hypobaric surrounding compared to a hyperbaric surrounding?

INTRODUCTION: The Eustachian tube (ET) is the key to pressure equalization between the middle ear and ambient pressure. To date, little is known about differences of the opening mechanisms under hyper- or hypobaric conditions. Aim of this study was to compare standard ET opening parameters during standardized hypo- and hyperbaric exposures. METHODS: Thirty healthy participants were exposed to a standardized profile of decompression and compression (SPDC) in a hypo-/hyperbaric pressure chamber. Impedance, expressed as tympanic membrane compliance, was recorded at intervals during the excursions from 1 atmosphere absolute (atm abs) to 0.8 and 1.2 atm abs respectively. Parameters for tubal opening were obtained during SPDC: ET opening pressure (ETOP), ET opening duration (ETOD) and ET opening frequency (ETOF), hypobaric (Phase 1) and hyperbaric (Phase 2) data were compared. RESULTS: Mean value for Valsalva maneuver ETOP was 40.10 ± 19.02 mbar in Phase 2 vs. 42.82 ± 21.75 mbar in Phase 1. For ETOD it was 2.80 ± 2.09 seconds in Phase 2 vs. 2.51 ± 1.90 seconds in Phase 1. For swallowing, mean value for ETOP was 33.47 ± 14.50 mbar in Phase 2 vs. 28.44 ± 14.04 in Phase 1. ETOD was 0.82 ± 0.60 seconds in Phase 2 vs. 0.76 ± 0.55 seconds in Phase 1. There was no statistical significance for ETOP, ETOD and ETOF between the two phases. CONCLUSION: No statistical significant difference was evident for active pressure equalization (Valsalva and swallowing) between a hyperbaric setting (dive) and a hypobaric setting (flight) in healthy subjects.

Effects of Pillar implants for sleep-related breathing disorders on middle ear function.

Pillar implants provide a reasonable outcome with minimal post-operative morbidity and complications in treating patients with sleep-disordered breathing (SDB) who had obvious palatal obstruction. The palatal structure is responsible for a normal functioning Eustachian tube; however, little is known if there is any potential otologic implication of minimally invasive palatal stiffening surgery for SDB. The aim of this study is to evaluate the effects of Pillar implantation on middle ear function. We performed a prospective study in a tertiary referral center. Thirty SDB patients (25 men, 5 women; mean age, 44.3 years) who underwent Pillar implants for treating palatal obstruction were enrolled. The subjects had normal otologic exam and no previous history of chronic ear disease. Pure-tone audiometry and tympanometry were performed pre-operatively, and post-operative days 1 and 7, and months 1 and 3. Baseline and post-operative middle ear pressures (MEPs) in decipascals were compared. Statistical analysis was performed by repeated measures of ANOVA. Eight patients (8/30, 26.7%) reported otologic complaints such as ear pressure and/or otalgia within 1 week post-operatively. No permanent otologic discomfort occurred. A trend toward reduced MEP was noted in this study. The decrease in MEP became apparent on post-operative day 1 after surgery. However, mean pressure changes were no longer significantly different from pre-operative values by 1 week after surgery. Pillar implantation for SDB induces changes in middle ear function. However, the changes were temporary and not significant 1 week after surgery.

[Anatomy of the eustachian tube]. / Anatomie der Tuba Eustachii.

The auditory tube is part of a complex anatomical functional system, which even today is not completely explained. It plays a crucial role in the understanding of the pathogenesis of chronic middle ear infections and possible therapeutic interventions--particularly in infants. This paper summarizes the current knowledge of eustachian tube gross anatomy and histology, its peritubular structures and its topographic relationship to the internal carotid artery in adults. Anatomical aspects specific to infancy are related to their possible influence on tube function.

[Characterizing the passive opening of the eustachian tube in a hypo-/hyperbaric pressure chamber]. / Charakterisierung der passiven Tubenöffnung in einer hypo-/hyperbaren Druckkammer.

BACKGROUND: Beside arbitrary and not arbitrary active pressure equalization systems there is a passive equalization system via the Eustachian tube (ET) at pressure difference between the epipharyngeal space and the middle ear. Aim of this study was to characterize this passive equalization system in a hypobaric/hyperbaric pressure chamber by continuously measuring the tympanic impedance. In contrast to other studies, which are measured only in a hypobaric pressure chamber it is possible to include participants with Eustachian tube dysfunction (ETD). MATERIAL AND METHODS: Following a fixed pressure profile 39 participants were exposed to phases of pressure rising and decompression. By continuously measuring the tympanic impedance in the pressure chamber it was possible to measure data of the Eustachian Tube opening Pressure (ETOP), Eustachian Tube closing pressure (ETCP) and Eustachian Tube opening duration (ETOD). In addition it was possible to characterize the gradient of pressure during decompression, while the ET was open. RESULTS: Beside the measurement of the arithmetic average of the ETOP (30.2 ± 15.1 mbar), ETCP (9.1 ± 7.7 mbar) and ETOD (0.65 ± 0.38 s) it was obvious that there are recurrent samples of pressure progression during the phase of tube opening. Generally it is possible to differentiate between the type of complete opening and partial opening. CONCLUSION: The fundamental characterization of the action of the passive tube opening, including the measurement of the ETOP, ETCP and ETOD, is a first step in understanding the physiological and pathophysiological function of the ET.

New insights into mechanism of Eustachian tube ventilation based on cine computed tomography images.

There is debate concerning the mechanism of Eustachian tube (ET) ventilation. While a mechanism of complete opening has been advocated previously, sequential contraction of the levator veli palatini and medial pterygoid muscles followed by the tensor veli palatini and lateral pterygoid muscles may produce a transient sequential opening mechanism, allowing an air bolus to traverse the ET. This may explain confusion surrounding sonotubometry reports that not every swallow leads to sound passage in normal subjects. We hypothesize that the ET may not need to open completely when ventilating the middle ear; rather, a discrete air bolus can pass through it. Five normal and five disordered subjects underwent low-radiation dose cine computed tomography (CT) scans of the ET. Sixteen contiguous 2.5 mm slice locations were chosen through a 4 cm area in the nasopharynx that were parallel to and encompassed the entire ET. Twelve images were acquired at each slice over 4.8 s during swallowing and other tasks. Serial images were analyzed. An air bolus was observed passing through the ET in the normal subjects, but not the subject with ET dysfunction. Medial and lateral pterygoid contractions were also observed. A new hypothetical mechanism of transient sequential ET ventilation is presented. This is not a definitive conclusion, as the number of scans taken and maneuvers used was limited. Improved understanding of ET ventilation may facilitate management of middle ear disease as treatment evolves from ventilatory tube placement to ET manipulation.

Active control of ultrasonic hearing in frogs.

Vertebrates can modulate the sound levels entering their inner ears in the face of intense external sound or during their own vocalizations. Middle ear muscle contractions restrain the motion of the middle ear ossicles, attenuating the transmission of low-frequency sound and thereby protecting the hair cells in the inner ear. Here we show that the Chinese concave-eared torrent frog, Odorrana tormota, can tune its ears dynamically by closing its normally open Eustachian tubes. Contrary to the belief that the middle ear in frogs permanently communicates with the mouth, O. tormota can close this connection by contraction of the submaxillary and petrohyoid muscles, drastically reducing the air volume behind the eardrums. Mathematical modeling and laser Doppler vibrometry revealed that the reduction of this air volume increases the middle ear impedance, resulting in an up to 20 dB gain in eardrum vibration at high frequencies (10-32 kHz) and 26 dB attenuation at low frequencies (3-10 kHz). Eustachian tube closure was observed in the field during calling and swallowing. Besides a potential role in protecting the inner ear from intense low-frequency sound and high buccal air pressure during calling, this previously unrecognized vertebrate mechanism may unmask the high-frequency calls of this species from the low-frequency stream noise which dominates the environment. This mechanism also protects the thin tympanic membranes from injury during swallowing of live arthropod prey.

Eustachian tube function in adults without middle ear disease.

OBJECTIVES: We sought to develop normative values for 5 eustachian tube function (ETF) test protocols in adults without otitis media (OM). METHODS: Twenty adults (19 to 48 years of age) without a recent history of OM (5 had OM in childhood) underwent unilateral myringotomy and were evaluated for ETF by use of the forced response, inflation, deflation, forcible "sniff", and Valsalva test protocols. When possible, these tests were repeated on a second day. RESULTS: Normative values for the parameters of these protocols in adult subjects without a recent history of OM were developed. Between-day data for the forced response test were highly correlated. A percentage of these tests showed eustachian tube "constriction" during swallowing--an abnormal condition. The percent reduction in applied pressures for the inflation and deflation tests was high, indicative of good ETF. Few subjects had a positive "sniff" test, whereas most had a positive Valsalva test, and the results for both tests were effort-dependent. CONCLUSIONS: Results of ETF tests in adults with and without recent OM have not been published. Normative data are now available for comparison with ETF test results in adults with OM. These protocols will be used to evaluate the efficacy of surgical procedures designed to improve ETF.