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Biomedical subjects

J V Hough

Publications and source records attributed to J V Hough.

At least 19 recordsLinked to original sources

Semi-implantable electromagnetic middle ear hearing device for moderate to severe sensorineural hearing loss.

Despite the many improvements in hearing aid technology, conventional hearing aids continue to have significant limitations, which has led to increased interest in implantable hearing devices. The SOUNDTEC Direct Drive Hearing System for moderate to moderately severe sensorineural hearing loss is one such device. In this article the authors present results on five individuals enrolled in a Food And Drug Administration Phase I feasibility study.

Auditory Threshold↗

Early clinical results: SOUNDTEC implantable hearing device phase II study.

OBJECTIVE: To assess the safety and efficacy of a new semi-implantable electromagnetic hearing device, the SOUNDTEC Direct Drive Hearing System (DDHS), and to compare its performance with that of subjects' previously worn, optimally fit hearing aids. Preliminary results for the first 10 subjects are presented. STUDY DESIGN: The protocol specified in the Investigational Device Exemption is used in this ongoing FDA phase II 100-subject multicenter clinical trial. METHODS: For baseline, each subject is tested wearing his or her own optimally fit hearing aid in the ear to be implanted. Six-month postoperative outcome measures using the SOUNDTEC DDHS are compared with the baseline. Multiple objective and subjective outcomes (as listed under Results) were measured. RESULTS: When compared with the subjects' optimally fit hearing aids, the SOUNDTEC DDHS provided an average improvement of 52% in functional gain (250-6000 Hz), 22% in aided thresholds, 3.8% for speech discrimination in quiet, 17% for speech in noise, 13.1% in articulation index scores, 28% in aided benefit, 27.3% in sound quality of speech, and a 16.7% increase in overall subject satisfaction. In addition, with the SOUNDTEC DDHS, subjects reported absence of acoustic feedback, little or no occlusive effects, and more natural sound perception. CONCLUSION: Analysis of data on the first 10 subjects using the SOUNDTEC DDHS indicates positive outcomes regarding safety and efficacy, although the small sample size is not sufficient to permit valid statistical inferences to be drawn from our preliminary data. Results also demonstrate improvement in performance compared with the subjects' optimally fit hearing aids and an improvement in quality of life as demonstrated by objective and subjective tests and measures.

Aged↗

Ossiculoplasty.

Homograft human bone is not only the most logical choice for grafting material, but also the closest transplantation material to the host histologically. This article discusses surgical repair of the ossicular chain with homograft bone transplants, including rationale for present surgical techniques, a thorough description of simple methods of microlathing homograft bone grafts, and instructions for maintaining an ossicular replacement bone bank. Furthermore, results in all types of ossiculoplasty and a method of classification of tympanoplasty are presented in this article.

Ear Ossicles↗

Acute human trial of the floating mass transducer.

Five patients underwent acute implantation of the Floating Mass Transducer (FMT) to evaluate the ability of the FMT to produce measurable auditory thresholds when temporarily placed in the middle ears of patients undergoing routine stapedotomy procedures. The FMT was placed on the long process of the incus in an inferior position, as is planned for clinical application, and in two additional positions. The ability of the FMT to produce measurable auditory thresholds was demonstrated in all patients. Results were affected by the lack of a healing period, the presence of a fixed stapes and an open middle ear space, and patient sedation.

Audiometry↗

Bone conduction implants for amplification: comparison of results.

We compared the results from the North American patient database on the Xomed Audiant Bone Conductor to those reported on the NobleBiocare (previously Noblepharma) HC200 bone-anchored hearing aid (BAHA) implant, using the literature and specific results provided by one of the authors. It has been proposed that the percutaneous coupling of the NobleBiocare implant transduces energy more powerfully than the Audiant transcutaneous coupling. If true, percutaneous coupling could provide greater amplification, helping patients experiencing both conductive and sensorineural hearing loss. Aided sound-field thresholds corresponding to bone-conduction thresholds were compared retrospectively through the speech frequencies. Both the BAHA and the Audiant devices amplified in the sound field to approximate preoperative bone-conduction thresholds. No statistically significant differences existed between the amplification of warble tones through the speech frequencies for either device. We conclude that amplification with the Audiant device offers as much gain as the HC200 device through the speech frequencies. While both devices can supply effective amplification for select patients suffering from conductive hearing loss, neither provides gain superior to preoperative bone-conduction thresholds to address the needs of select patients with a substantial sensorineural component.

Adult↗

Selection of biomaterials for middle and inner ear implants.

In the selection of biomaterials for middle ear applications of implantable devices, certainly the site of implantation and the mass of the implant will dictate the choice of biomaterials. Hermetic sealing of an implant is best achieved by the use of metals, not polymers. Osteocompatibility of an ossicular implant can be enhanced by the incorporation of calcium phosphates such as hydroxyapatite coatings. Finally, osseointegration or osseofixation is neither necessary nor desirable for ossicular implants, because (1) they may need to be removed or replaced in the future and (2) their solid fixation to an ossicle is not necessary for the vibratory function of hearing amplification.

Biocompatible Materials↗

Long-term results for the Xomed Audiant Bone Conductor.

The Audiant Bone Conductor is now used worldwide. Results consistently demonstrate that when used on patients within the recommended criteria, hearing thresholds are improved to within 10 dB of the preoperative bone conduction threshold. In this article, comparisons are made with the reported results of the Audiant versus other comparable bone conduction devices, or with surgical procedures for conditions such as congenital aural atresia.

Auditory Threshold↗

The Audiant Bone Conductor: update of patient results in North America.

The Xomed Audiant Bone Conductor is an implantable hearing device for conductive hearing impairments not adequately relieved by surgical methods or hearing aid amplification. It has now been used long enough for analysis of its present position in our management armamentarium. Data obtained from respondents from the United States and Canada are presented and indicate that this device, properly prescribed and used, almost eliminates the conductive elements of the hearing impairment. During the early years of its use, the device was frequently implanted in patients outside the manufacturer's guidelines for use. Some of the reasons for this discrepancy, as well as evidence that this misapplication is lessening, are presented. When proper guidelines were used, however, the results presented here indicate that socially adequate hearing can be restored to patients with conductive loss by the Audiant. Complications have been few and appear to be diminishing. The results indicate that this device has, in its present state of development, a narrow and restrictive application, but a well-defined and efficient role to play in the management of conductive hearing impairment.

Adolescent↗

Kabuki make-up syndrome and hearing impairment.

In 1981, Niikawa et al. and Kuroki et al. independently described patients with a new syndrome consisting of mental retardation, postnatal growth deficiency and unusual facial features such as long palpebral fissures with eversion of the lateral one-third of the lower eyelids, arched and laterally sparse eyebrows and large prominent ears among other malformations. The condition has been called Kabuki make-up syndrome because the facial features in affected individuals resemble the make-up of the actors in a Japanese play: Kabuki. After the initial reports on Japanese individuals, the condition has been observed in several other patients of different ethnic origins including a few patients from this country (Kaiser-Kupfer et al., 1986; Pagon et al., 1986). We describe an additional 13-year-old male patient with Kabuki make-up syndrome with possible implication of autosomal dominant inheritance from his mother. Interestingly, our patient also displayed hitherto unreported severe ossicular malformations resulting in significant hearing impairment.

Abnormalities, Multiple↗

Stapedectomy. Causes of failure and revision surgery in otosclerosis.

The greatest chance of success in stapedectomy is at the time of the initial procedure. Complications are compounded and successes markedly decreased when revision surgery is attempted. The most common pitfalls encountered in stapedectomy are reviewed in this article. Principles of surgery that have minimized complications and decreased the need for revision procedures in the authors' practices are outlined. Guidelines helpful when considering revision surgery also are presented and specific indications are addressed.

Humans↗

The safety and effectiveness of an implanted electromagnetic hearing device.

The records of 184 patients implanted with the XOMED Audiant Bone Conductor (XOMED Inc, Jacksonville, Fla) prior to March 1988 were reviewed retrospectively to determine the safety of this device. Complications were few and minor in nature. Effectiveness was judged from the audiometric data obtained from the 96 patients in the hearing part of this study, all of whom had improved hearing with the device. The mean preoperative pure-tone air-conduction three-frequency average threshold +/- SD in the implanted ear was 55.8 +/- 10.7-dB hearing level; postoperative average aided warble-tone threshold was 19.9 +/- 8.5-dB hearing level. The average improvement in threshold was 36.0 +/- 13.3 dB. Ninety-three percent of patients achieved socially adequate hearing, ie, mean aided sound-field thresholds of at least 30-dB hearing level, and 81% had thresholds of at least 25-dB hearing level. We conclude that the XOMED Audiant Bone Conductor is a safe and effective device for the surgical correction of conductive hearing loss.

Adolescent↗

Histologic findings in two very small intracanalicular solitary schwannomas of the eighth nerve: II. "Onion bulbs".

An "onion bulb" is a descriptive histologic term referring to concentric layers of Schwann cell processes about a myelinated nerve fiber. Between the layers of Schwann cells are increased amounts of longitudinally oriented collagen fibers. It is thought that onion bulbs form as a result of sequential segmental demyelination and remyelination attempts. This process can become so severe that the myelinated fiber loses its myelin and ultimately degenerates; however, many fibers remain viable and thinly myelinated. The physiologic effect of "onion bulbs" is to markedly decrease conduction velocity in the fiber affected. In the auditory system, incompletely myelinated cochlear nerve fibers in the infant and in patients with multiple sclerosis show delays of the auditory evoked potential latencies and psychoacoustic retrocochlear patterns. No anatomic substrate has been identified for these auditory tests patterns in the acoustic tumor (solitary schwannoma of the eighth nerve). Two very small intracanalicular acoustic tumors were resected en bloc with the nerve of origin, serially sectioned, stained for neural tissue, and studied by light microscopy. In both tumors, histologic findings consistent with onion bulb formation were discovered about some of the myelinated nerve fibers found deeply incorporated in the tumor mass. These findings suggest that demyelination, perhaps with the formation of onion bulbs, may be a histopathologic correlate for retrocochlear dysfunction seen in acoustic tumors.

Cranial Nerve Neoplasms↗

An implantable hearing device: osseointegration of a titanium-magnet temporal bone stimulator.

The use of bone conduction hearing devices has recently entered the realm of implantable prostheses and solid-state electronics, resulting in improved fidelity and applicability for a wider range of patients. One particular device, a temporal bone stimulator (TBS), consists of an external sound processor and implanted portion to cause vibration under the skin. An implantable temporal bone stimulator screw constructed of titanium alloy with a permanent magnet can be vibrated by inductive transcutaneous coupling. The safety and osseointegration of the TBS bone screw were tested in adult goats that were free-field stimulated at 75 dB with the TBS processor for 4 to 21 weeks. Histologic comparisons of the soft tissue and bone adjacent to active and passive screws revealed no remarkable differences between them with bone growing in the interstices of the threaded portion. Evidence for mild reorganization of bone was shown with Goldner's stain, which differentiated bone that was young and unmineralized from bone that was older and mineralized. Reorganization was evident in both the active and passive sites and there was no remarkable difference between the two in a blind study. Additional evidence for the integrity of the implant was obtained by subjecting a calvarium containing both screws to a 5000 gauss magnetic field for 10 minutes of a nuclear magnetic resonance head scan. The calvarium was first dissected free from overlying skin and connective tissue. The magnet-containing screws were not loosened. We conclude that the implanted screw portion of the TBS implantable hearing device is well-integrated into the temporal bone. Mild stimulation of new bone growth indicates a healthy long-term viable implant for bone conduction amplification of sound.

Animals↗

The use of rare-earth magnet couplers in cochlear implants.

The cochlear implant is an electronic auditory prosthesis gaining widespread acceptance as a means of restoring partial hearing to the totally deaf. A number of engineering and biological hurdles remain toward the improvement of existing implantable systems and development of multichannel systems. One hurdle concerns reliable transcutaneous coupling of the external electric signal to the implanted device. To date this has been accomplished by inductive means through coils which were mechanically held in place. The incorporation of small, permanent, rare-earth (SmCo5) magnets with the coil assemblies has eliminated the unreliable mechanical supporting devices. Magnetic attachment was simulated in dogs to examine for biological compatibility. Electron micrographs indicated normal subcellular structures in tissue exposed for 10 weeks. Five patients were implanted with magnet-modified coil assemblies and tested for the proper alignment and support of the external coil assembly, as well as efficiency of inductive coupling. Electromagnetic coupling was not interfered with and mechanical support was adequate. We conclude that rare-earth magnets provide an effective means for supporting and positioning in place medical devices, such as the cochlear implant.

Animals↗

Results following cochlear implantation and rehabilitation.

Nine post-lingually deafened adults received single-electrode cochlear implants and afterwards participated in a rehabilitation program. For these nine patients the average threshold sensitivity in soundfield was significantly better with use of the cochlear prosthesis than with hearing aid amplification in the same ear prior to implantation. Significant changes also occurred in discrimination of environmental sounds, recognition of words and stress patterns, and in speechreading skill. Certain aspects of phonation (harshness, control of intensity, and habitual pitch). and some articulation problems improved, while inflection abnormalities were not altered. Data concerning daily hours of implant activation, an indicator of patient acceptance, reveal that seven of the nine use their cochlear prosthesis for at least eight hours per day. These results suggest that the single electrode cochlear implant is a clinically useful tool in the rehabilitation of selected profoundly deaf individuals.

Adult↗