Blog Archives

Middle ear metastasis of thymoma

Conclusion
We have not found out thymoma metastases to the middle ear in the past.

from Auris Nasus Larynx

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Insertion of middle-ear Silastic sheeting during tympanoplasty: hearing outcomes

Results: Patients who had undergone Silastic sheet insertion showed significantly better air conduction, bone conduction and air–bone gap averages one year post-operatively, compared with those who had not.

from the Journal of Laryngology and Otology

Superior semicircular canal dehiscence and lack of the tympano-ossicular system: Favourable functional aspects of a coincidental finding

Objectives: Our objectives were to report the functional conditions of superior semicircular canal dehiscence (SSCD) associated with the post-inflammatory lack of tympano-ossicular system. Methods: A 40-year-old male, initially referred for bilateral ear discharge due to a left cholesteatoma and a right unstable ‘intact bridge’ tympanoplasty, underwent a left open mastoidectomy without a tympano-ossicular reconstruction. Two years later, he had a conversion of the ‘intact bridge’ tympanoplasty into an open mastoidectomy without reconstruction on the right side. Moreover, he had a bilateral SSCD diagnosed by means of vestibular evoked myogenic potentials (VEMPs) and high-resolution computed tomography (HRCT). Results: Combination of the absence of the tympano-ossicular system and SSCD resulted in surprisingly good hearing function. Conclusions: The reported bilateral near-to-normal hearing function outlines the possibility of a favourable outcome deriving from the association of two different adverse conditions. This presents an opportunity for reflection on the pathophysiology of sound transmission, and indicates the usefulness of including the radiological investigation of the bone overlying the superior semicircular canal even when investigating inflammatory middle ear diseases.<p><p>from <a href=”Audiological” _mce_href=”http://informahealthcare.com/doi/abs/10.3109/1651386X.2011.559381″><em>Audiological”>http://informahealthcare.com/doi/abs/10.3109/1651386X.2011.559381″><em>Audiological Medicine</em></a></p>

Intratympanic injection with dexamethasone for sudden sensorineural hearing loss

Conclusion: Intratympanic steroid injection may be a simple and effective treatment for patients with sudden sensorineural hearing loss.

from the Journal of Laryngology and Otology

The Effect of Static Ear Canal Pressure on Human Spontaneous Otoacoustic Emissions: Spectral Width as a Measure of the Intra-cochlear Oscillation Amplitude

Spontaneous otoacoustic emissions can be detected as peaks in the Fourier spectrum of a microphone signal recorded from the ear canal. The height, center frequency, and spectral width of SOAE peaks changed when a static pressure was applied to the ear canal. Most commonly, with either increasing or decreasing static pressure, the frequency increased, the amplitude decreased, and the width increased. These changes are believed to result from changes in the middle ear properties. Specifically, reduced middle ear transmission is assumed to attenuate the amplitude of emissions. We reconsidered this explanation by investigating the relation between peak height and width. We showed that the spectral width of SOAE peaks is approximately proportional to . This is consistent with a (Rayleigh) oscillator model in which broadening of the SOAE peak is caused by broadband intra-cochlear noise, which is assumed to be independent of static ear canal pressure. The relation between emission peak height and width implicates that the intra-cochlear oscillation amplitude attentuates relative to the intra-cochlear noise level when a static ear canal pressure is applied. Apparently, ear canal static pressure directly affects the active mechanics in the inner ear.

from JARO — Journal of the Association for Research in Otolaryngology

Subjective and objective outcomes of tympanoplasty surgery at National Hospital Abuja, Nigeria 2005–2009

The objective of this study is to determine the subjective and objective outcomes of tympanoplasty surgery carried out in patients with otitis media and to identify factors responsible for these outcomes. The study setting is tertiary care urban referral hospital in a developing economy and the study methodology is a prospective analysis of patients with diagnosis of chronic suppurative otitis media that had tympanoplasty with or without mastoidectomy between May 2005 and September 2009 at National Hospital Abuja. Subjects were evaluated for age, sex, size and site of perforation, status of operated ear(s) (dry/discharging), status of the contralateral ear, surgical technique, subjective and objective pre-operative and post-operative hearing scores, average post-operative follow-up time, and post-operative complications, and results were statistically analyzed. A total of 45 patients (51 ears) were operated. Age distribution was 8–52 years. Type 1 tympanoplasty was done in 41 patients and Type 3 in 4 patients. Seven of the patient had concomitant mastoid surgery (cortical mastoidectomy). 3/51 of the cases had discharging ears at surgery. 16/45 of the patients (19/51 ears) had cartilage graft tympanoplasty, while 29/45 (32 ears) had temporalis fascia tympanoplasty. 15/16 of the cartilage group as well as 26/29 of the fascia group reported subjective hearing improvement, whilst the actual graft take was 12/16 of the cartilage group and 23/29 of the fascia group. Objective hearing improvement was observed in all of the cartilage as well as 26/29 of the fascia group. This study confirms success of tympanoplasty among Nigerians, and recommends that subjective hearing assessment should form part of indicators for success following tympanoplasty.

from the European Archives of Oto-Rhino-Laryngology

CO2 gas exchange across the human tympanic membrane is not appreciably affected by pathology

Past in vivo studies in humans showed that the tympanic membrane (TM) is permeable to physiological gases. Animal studies show that transTM CO2 conductance is increased by TM pathology. The objective of the study was to determine if transTM CO2 exchange in humans is affected by atrophic and sclerotic pathologies. The study used an ear canal (EC) probe (ECP) constructed from a custom-fitted acrylic body, a glass capillary tube enclosing an oil meniscus to maintain ambient ECP + EC pressure and a silica glass microtube linked to a mass spectrometer (MS) for measuring gas composition that was hermetically sealed within the ear canal of the test ear. ECP + EC volume was measured and gas samples taken at 10 min intervals for 1 h. The fractional CO2 pressure measured in the ECP + EC for each sample was regressed on time and the slope of the function multiplied by the ECP + EC volume and divided by the estimated transTM CO2 gradient at the start of the experiment to yield transTM CO2 conductance (µL/min/Pa). Data were complete for 15 normal, 13 sclerotic and 9 atrophic TMs. The average (+std) transTM CO2 conductances were 1.76 × 10−4 + 7.27 × 10−5, 2.26 × 10−4 + 1.5 × 10−4 and 2.36 × 10−4 + 1.14 × 10−4 µL/min/Pa/TM for the normal, sclerotic and atrophic TMs, respectively. A pairwise comparison of data for the normal and atrophic TMs under the directional hypothesis of a greater CO2 exchange rate for thinner TMs approached statistical significance (P = 0.07). A similar pairwise comparison for the sclerotic and normal TMs did not approach statistical significance (P = 0.28). The effect of TM pathologies on CO2 conductance was limited.

from the European Archives of Oto-Rhino-Laryngologyl

Cortical representation of tympanic membrane movements due to pressure variation: An fMRI study

Middle ear sensory information has never been localized in the homunculus of the somatosensory cortex (S1). We investigated the somatosensory representation of the middle ear in 15 normal hearing subjects. We applied small air pressure variations to the tympanic membrane while performing a 3T-fMRI study. Unilateral stimulations of the right ear triggered bilateral activations in the caudal part of the postcentral gyrus in Brodmann area 43 (BA 43) and in the auditory associative areas 42 (BA 42) and 22 (BA 22). BA 43 has been found to be involved in activities accompanying oral intake and could be more largely involved in pressure activities in the oropharynx area. The tympanic membrane is indirectly related to the pharynx area through the action of tensor tympani, which is a Eustachian tube muscle. The Eustachian tube muscles have a role in pressure equalization in the middle ear and also have a role in the pharyngeal phase of swallowing. Activation of BA 42 and BA 22 could reflect activations associated with the bilateral acoustic reflex triggered prior to self-vocalization to adjust air pressure in the oropharynx during speech. We propose that BA 43, 42, and 22 are the cortical areas associated with middle ear function. We did not find representation of tympanic membrane movements due to pressure in S1, but its representation in the postcentral gyrus in BA 43 seems to suggest that at least part of this area conveys pure somatosensory information.

from Human Brain Mapping

Congenital stapedial suprastructure fixation with normal footplate mobility: case report

Conclusion: This is a rare case of congenital stapedial suprastructure fixation with normal footplate mobility. In this patient, development of the second branchial arch was arrested. When performing exploratory tympanotomy for stapedial fixation, one must keep in mind that normal footplate mobility is possible.

from the Journal of Laryngology and Otology

Evaluation of implantable actuators by means of a middle ear simulation model

The extension of indication of implantable hearing aids to cases of conductive hearing loss pushed the development of these devices. There is now a great variety of devices available with different actuator concepts and different attachment points to the middle ear or inner ear fluid. But there is little comparative data available about the devices to provide an insight into advantages and disadvantages of different types of actuators and attachment points at the ossicular chain.

This paper investigates two principle (idealized) types of actuators in respect of attachments points at the ossicular chain and direction of excitation. Other parts of implantable hearing aids like microphone, amplifier and signal processing electronics were not incorporated into this study.

Investigations were performed by means of a mathematical simulation model of the middle ear (finite element model). Actuator performance and theoretical gain were calculated by harmonic analysis in the frequency range of 100–6000 Hz and were compared for the different situations.

The stapes head proofed to be an ideal attachment point for actuators of both types as this position is very insensitive to changes in the direction of excitation. The implantable actuators showed higher ratio of equivalent sound pressure to radiated sound pressure compared to an open hearing aid transducer and should therefore allow for more functional gain.

from Hearing Research

Reconstruction and exploration of virtual middle-ear models derived from micro-CT datasets

Conclusions
We have developed an intuitive, rapid, and effective means of exploring otological micro-CT datasets. This system may provide a foundation for additional work based on middle-ear anatomical data.

from Hearing Res

Copyright © 2009 Published by Elsevier B.V. Performance Considerations of Prosthetic Actuators for Round-Window Stimulation

Round window (RW) stimulation has improved speech perception in patients with mixed hearing loss. In cadaveric temporal bones, we recently showed that RW stimulation with an active prosthesis produced differential pressure across the cochlear partition (a measure related to cochlear transduction) similar to normal forward sound stimulation above 1 kHz, when contact area between the prosthesis and RW is secured. However, there is large variability in the hearing improvement in patients implanted with existing modified prosthesis. This is likely because the middle-ear prosthesis used for RW stimulation was designed for a very different application.

In this paper we utilize recently developed experimental techniques that allow for the calculation of performance specifications for a RW actuator. In cadaveric human temporal bones (N=3), we simultaneously measure scala vestibuli and scala tympani intracochlear pressures, as well as stapes velocity and ear-canal pressure, during normal forward sound stimulation as well as reverse RW stimulation. We then calculate specifications such as the impedance the actuator will need to oppose at the RW, the force with which it must push against the RW, and the velocity and distance by which it must move the RW to obtain cochlear stimulation equivalent to that of specific levels of ear canal pressure under normal sound stimulation. This information is essential for adapting existing prostheses and for designing new actuators specifically for RW stimulation.

from Hearing Research

A Totally Implantable Hearing System – Design and Function Characterization in 3D Computational Model and Temporal Bones

Implantable middle ear hearing devices are emerging as an effective technology for patients with mild to moderately severe sensorineural hearing loss. Several devices with electromagnetic or piezoelectric transducers have been investigated or developed in the US and Europe since 1990. This paper reports a totally implantable hearing system (TIHS) currently under investigation in Oklahoma. The TIHS consists of implant transducer (magnet), implantable coil and microphone, DSP-audio signal processor, rechargeable battery, and remote control unit. The design of TIHS is based on a 3D finite element model of the human ear and the analysis of electromagnetic coupling of the transducer. Function of the TIHS is characterized over the auditory frequency range in three aspects: (1) mass loading effect on residual hearing with a passive implant, (2) efficiency of electromagnetic coupling between the implanted coil and magnet, and (3) functional gain of whole unit in response to acoustic input across the human skin. This paper focuses on mass loading effect and the efficiency of electromagnetic coupling of TIHS determined from the FE model of the human ear and the cadaver ears or temporal bones. Some preliminary data of whole unit function are also presented in the paper.

from Hearing Research

Neural control of eustachian tube function

Conclusions:
Neuronal control mechanism could play an important role in regulating Eustachian tube function in humans. Laryngoscope, 2009

from Laryngoscope

Hearing results following intratympanic gentamicin perfusion for Ménière’s disease

Conclusion: Intratympanic gentamicin perfusion provides effective control of vertigo in patients with Ménière’s disease. However, significant hearing loss may occur immediately after perfusion; therefore, this treatment should be considered only for patients whose hearing has already been affected by the disease.

from the Journal of Laryngology and Otology