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.

Finite element modeling of sound transmission with perforations of tympanic membrane.

A three-dimensional finite element (FE) model of human ear with structures of the external ear canal, middle ear, and cochlea has been developed recently. In this paper, the FE model was used to predict the effect of tympanic membrane (TM) perforations on sound transmission through the middle ear. Two perforations were made in the posterior-inferior quadrant and inferior site of the TM in the model with areas of 1.

Combined effect of fluid and pressure on middle ear function.

In our previous studies, the effects of effusion and pressure on sound transmission were investigated separately. The aim of this study is to investigate the combined effect of fluid and pressure on middle ear function. An otitis media with effusion model was created by injecting saline solution and air pressure simultaneously into the middle ear of human temporal bones.

Tympanometry and laser Doppler interferometry measurements on otitis media with effusion model in human temporal bones.

Hypothesis: The aim of this study is to investigate the effect of middle ear fluid and pressure on tympanic membrane mobility by using laser Doppler interferometry and to compare these results with tympanometry.

Background: Tympanometry has been commonly used for evaluation of otitis media with effusion, a middle ear disease with fluid in the cavity. However, this test lacks specific interpretations of middle ear disorders based on tympanometric data.

Fixation and detachment of superior and anterior malleolar ligaments in human middle ear: experiment and modeling.

The aim of this study is to investigate the function of the superior malleolar ligament (SML) and the anterior malleolar ligament (AML) in human middle ear for sound transmission through simulations of fixation and detachment of these ligaments in human temporal bones and a finite element (FE) ear model. Two laser vibrometers were used to measure the vibrations of the tympanic membrane (TM) and stapes footplate. A 3-D FE ear model was used to predict the transfer function of the middle ear with ligament fixation and detachment.

Bacterial contamination of stethoscopes with antimicrobial diaphragm covers.

Antimicrobial stethoscope covers impregnated with silver ions have been developed to prevent surface contamination and potential transmission of bacterial pathogens to patients. To test their practical utility, covers were distributed with the manufacturers' recommendations to a mixed group of health care professionals in a medical/surgical intensive care unit and an emergency department. Seventy-four clinicians were selected from a convenience sample for surface cultures and standard questioning regarding cleaning and cover use.

Laser interferometry measurements of middle ear fluid and pressure effects on sound transmission.

An otitis media with effusion model in human temporal bones with two laser vibrometers was created in this study. By measuring the displacement of the stapes from the medial side of the footplate, the transfer function of the middle ear, which is defined as the displacement transmission ratio (DTR) of the tympanic membrane to footplate, was derived under different middle ear pressure and fluid in the cavity with a correction factor for cochlear load. The results suggest that the DTR increases with increasing frequency up to 4k Hz when the middle ear pressure was changing from 0 to 20 or -20 cm H20 (e.

Acoustic-structural coupled finite element analysis for sound transmission in human ear--pressure distributions.

A three-dimensional (3D) finite element (FE) model of human ear with accurate structural geometry of the external ear canal, tympanic membrane (TM), ossicles, middle ear suspensory ligaments, and middle ear cavity has been recently reported by our group. In present study, this 3D FE model was modified to include acoustic-structural interfaces for coupled analysis from the ear canal through the TM to middle ear cavity. Pressure distributions in the canal and middle ear cavity at different frequencies were computed under input sound pressure applied at different locations in the canal.

Human middle ear transfer function measured by double laser interferometry system.

Hypothesis: Simultaneous measurements of vibrations on the stapes footplate, incudostapedial (IS) joint, and tympanic membrane (TM) can be made in both normal and drained cochleae, and the stapes displacement transfer function (S-DTF) and TM displacement transfer function (TM-DTF) are derived.

Background: A single laser Doppler interferometer previously has been used for measuring movement of the stapes or TM in temporal bones. However, there may be a limitation to optimally describing acoustic-mechanical transmission when the interferometer and temporal bone are moved frequently during experimental recordings.

Middle ear electromagnetic semi-implantable hearing device: results of the phase II SOUNDTEC direct system clinical trial.

Objective: To assess the safety and efficacy of the SOUNDTEC Direct System, a partially implantable electromagnetic middle ear hearing device.

Study Design: Food and Drug Administration Phase II clinical trial of 103 patients at 10 sites across the United States.

Setting: Tertiary referral medical centers.

Homograft microlathed femur prosthesis in stapedectomy.

The use of homografts in ossiculoplasty has been well documented in the literature. In the early 1980s, nonossicular homograft otic capsule bone was used as a prosthetic material in stapedectomy. We began using homograft femur as a prosthetic material in the early 1990s.