Biomedical subjects

B J Gantz

Publications and source records attributed to B J Gantz.

96 records · Page 6Linked to original sources

PubMedDate not supplied

Audiological results with two single channel cochlear implants.

We tested six patients with single channel cochlear implants on several tests from the Minimal Auditory Capabilities battery and the Iowa Cochlear Implant Tests. All patients were able to discriminate some everyday sounds and to identify the number of syllables in the words presented. Five patients were able to identify speaker sex reliably. Surprisingly, some patients had difficulty discriminating between a modulated noise and a voice or between a question and a statement or identifying the accented word in a sentence. On several audiovisual tests, an improvement was observed for the sound plus vision condition compared to the vision only condition. This was particularly true for sentence tests, but was not uniform across patients or across tests.

Adult↗

PubMedDate not supplied

Middle cranial fossa acoustic neuroma excision: results and complications.

The middle cranial fossa surgical approach has been used for the removal of acoustic neuromas in 43 patients at the University of Iowa since 1974. Hearing was maintained in 50% of patients with tumors 1.5 cm or less outside the porus acusticus. Postoperative hearing, facial nerve function, and complications were similar to reports using the suboccipital or retrosigmoid approach to preserve hearing for this size tumor. The character of the tumor appears to dictate the postoperative outcome rather than the surgical approach.

Adult↗

PubMedDate not supplied

Localization of collagenase in chronically inflamed guinea pig temporal bone.

Bone destruction, commonly associated with chronic otitis media, requires collagen degradation. Collagenase, a neutral protease, appears to be an essential component in the process of collagen breakdown. Collagenase was identified within chronically inflamed and normal guinea pig temporal bones using an immunohistochemical technique with fluorescein isothyocyanate and peroxidase-antiperoxidase labels. Localization of the enzyme identifies sites of matrix resorption. Collagenase was found in osteoclasts, osteocytes, mononuclear inflammatory cells, and at resorbing margins. Inflammation increased the intracellular collagenase content of inflammatory bone osteocytes when compared to normal osteocytes using a microspectrofluorometer. It appears that the inflammatory process directly influences bone destruction through the action of mononuclear inflammatory cells and indirectly by stimulating bone cells to increase their proteolytic enzyme production.

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PubMedDate not supplied

Survival of implanted irradiated cartilage.

As a result of our study the following conclusions may be drawn: 1. Irradiated homograft costal cartilage appears to survive as a nonviable implant in part replaced by host tissue in the cat. 2. Such replacement may be minimized by leaving as much perichondrium intact as is feasible. 3. Boiling or freezing fresh autogenous cartilage in an attempt to alter its warping characteristics is asking for increased resorption.

Animals↗

PubMedDate not supplied

Performance of adult Ineraid and Nucleus cochlear implant patients after 3.5 years of use.

Forty-two postlingually deafened adult patients, 21 with a formant extraction version of the Nucleus cochlear implant and 21 with the Ineraid cochlear implant (analog processing), were evaluated on a series of speech perception tests after using their implants for about 3.5 years. A wide range of performance was observed across patients for both devices. All but 4 patients showed an enhancement in their lipreading ability with the implant. Word recognition averaged about 14-19% correct, and word recognition in sentences averaged about 43-49% correct for the two implant groups. Average performance was superior with the Ineraid implant on consonant recognition in noise. An information transmission analysis suggested that vowel perception was influenced by first- and third-formant frequency for the Nucleus, and first-formant and fundamental frequency for the Ineraid patients. It appeared that the Ineraid device was more effective, on average, at conveying information about consonant nasality and frication. For consonant perception, nasality and frication contributed most to the total information transmitted for both implant types. Both devices had difficulty conveying information about vowel second-formant frequency and consonant place information. These scores at 3.5 years are substantially elevated from preoperative performance and, overall, the patients clearly benefit from their implant.

Adult↗

PubMedDate not supplied

Gadolinium-enhanced MR of the postoperative internal auditory canal following acoustic neuroma resection via the middle fossa approach.

PURPOSE: To evaluate the ability of gadolinium-enhanced MR in detecting recurrent tumor in patients whose acoustic neuromas were surgically removed via the middle cranial fossa approach. PATIENTS AND METHODS: Postoperative gadolinium-enhanced exams of 13 of 44 patients who underwent excision of acoustic neuromas via the middle cranial fossa approach were reviewed. RESULTS: Postoperative enhancement was seen in 12 of the 13 patients; two patients underwent serial exams without significant change. On the basis of a single exam, we were unable to conclusively differentiate postoperative enhancement from residual or recurrent tumor. CONCLUSIONS: A single exam is of limited value. Serial studies are recommended to identify changes that would indicate tumor growth. A proposed MR follow-up schedule is an initial baseline exam within 2 months of surgery and a repeat exam during the second postoperative year.

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