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Biomedical subjects

B J Gantz

Publications and source records attributed to B J Gantz.

At least 55 records · Page 3Linked to original sources
PubMed1995

Medullary carcinoma of the thyroid metastatic to the temporal bone.

We report a case of proven thyroid medullary carcinoma, metastatic to the temporal bone. Review of the otolaryngology literature demonstrates that this is the first such report. The patient presented with symptoms, physical examination, and imaging studies suggestive of a glomus jugulare tumour. The pre-operative diagnosis of metastatic thyroid medullary carcinoma, however, was made, based on a history of medullary carcinoma of the thyroid with previous metastases as well as an elevation in calcitonin levels. Histological examination of the surgical specimen confirmed the diagnosis.

Carcinoma, Medullary↗
PubMed1995

Longitudinal assessment of physiological and psychophysical measures in cochlear implant users.

OBJECTIVE: The purpose of this study was to evaluate the effects of long-term electrical stimulation on human cochlear implant users. DESIGN: Repeated measures of electrically evoked auditory brain steam response (EABR) threshold, slope of the EABR growth function, and behavioral measures of threshold and dynamic range were made for a group of 22 Ineraid cochlear implant users and 19 Nucleus cochlear implant users over a 3- to 5-yr period. RESULTS: Data from both Ineraid and Nucleus cochlear implant users suggest that EABR threshold, slope of the EABR growth function, and behavioral measures of threshold and dynamic range remain reasonably stable for periods up to 5 yr postimplant. CONCLUSIONS: The results of this study show little evidence that prolonged electrical stimulation through daily use of a cochlear implant has deleterious effects on the auditory system.

Cochlear Implants↗
PubMed1995

Preliminary results with the Clarion cochlear implant in postlingually deaf adults.

A clinical trial of three different multichannel cochlear implants is in progress at The University of Iowa. Fifty postlingually deaf adults participated in a prospective randomized study of the Nucleus implant and the Ineraid device. Subsequently, 23 consecutive postlingually deaf adults have been implanted with the Clarion system. The speech perception performance obtained after 9 months of implant use with all devices was compared. In addition, Clarion patient results at 9 months were compared with long-term (36 months) results from subjects using the other two multichannel implants. Preliminary speech perception scores on the Iowa sentence test (sound-only) and NU-6 words (sound-only) demonstrate that the Clarion subjects, as a group, perform at higher levels than subjects using the other two systems. A wide range of performance is observed with all devices. The continuous interleaved pulsatile strategy of the Clarion device appears to be advantageous for this group of subjects.

Adult↗
PubMed1995

Tinnitus and acoustic neuromas: analysis of the effect of surgical excision on postoperative tinnitus.

In this retrospective review of the 160 acoustic neuroma cases treated at The University of Iowa between 1980 and 1991, follow-up information was obtained for 82% by telephone interview. Postoperative tinnitus was a symptom reported by 75% of the acoustic neuroma patients. Overall, among patients with tinnitus preoperatively, the condition postoperatively was absent in 45%, lessened in 17%, unchanged in 30%, and greater in 8%. Detailed results are compared to other series and significant differences in the depth of comparison described.

Age Factors↗
PubMed1995

Diatrizoate and dextran treatment of sudden sensorineural hearing loss.

Many treatments have been proposed to manage sudden sensorineural hearing loss. The University of Iowa has used a protocol of intravenous radiopaque contrast and volume expander for the last 10 years in the treatment of sudden sensorineural hearing loss. A retrospective analysis of these cases was performed to review the efficacy of this treatment with respect to the natural history of the disease, as reported in previous studies. Sixty-four percent of 39 cases showed audiometric improvement in their pure-tone averages, speech reception thresholds, and speech discriminations while receiving treatment. Forty-eight percent of these showed improvement after their first treatment doses. Eighty percent of patients who presented more than 7 days after the onset of their hearing loss showed audiometric improvement with treatment, whereas 71 percent of patients presenting before 7 days showed audiometric improvement. However, the patients who presented earlier showed more marked improvement. Speech discrimination with the W-22 word list was a predictor of early recovery. Patients with measurable speech discrimination scores on presentation uniformly improved with treatment, even if their pure-tone average was profound. Our findings were suggestive of a pathophysiologic mechanism for some cases of sensorineural hearing loss for which intravenous contrast is efficacious. Although our findings were far from conclusive in this uncontrolled study, these initial results support the use of these agents in a rigorous clinical trial.

Adolescent↗
PubMed1994

Glomus jugulare tumors masquerading as benign intracranial hypertension.

Intracranial hypertension has been reported as a complication of massive glomus jugulare tumors with intracranial extension. We describe a patient with papilledema, failing vision, and a diagnosis of benign intracranial hypertension with bilateral glomus jugulare tumors that went undetected for 2 years. There was no evidence of intracranial invasion by the tumors to explain the elevation of intracranial pressure. Embolization followed by surgical removal of the left tumor resulted in stabilization of the neurologic condition and preservation of the lower cranial nerves, including intact hearing. The likely mechanism of intracranial hypertension in this case is an impairment of cerebrospinal fluid absorption. This unusual presentation should be recognized to avoid delayed diagnosis and treatment. Furthermore, intracranial hypertension is not always associated with massive intracranial tumor involvement, as had been previously proposed.

Adult↗
PubMed1994

Mondini dysplasia and congenital cytomegalovirus infection.

We report a case of bilateral temporal bone anomalies in a child with symptomatic congenital cytomegalovirus infection and severe, bilateral sensorineural hearing loss identified at 3 months of age. High-resolution temporal bone computed tomography (HRCT) revealed bilateral findings of a short, malformed cochlea lacking an interscalar septum, a short and wide internal auditory canal, and an enlarged vestibular aqueduct, features diagnostic of bilateral Mondini dysplasia. To determine the importance of this observation, we completed HRCT in five additional children between 7 months and 9 years of age who had evidence of symptomatic congenital cytomegalovirus infection. One child with profound sensorineural hearing loss had severe bilateral temporal bone dysplasia with a small cochlea lacking an interscalar septum, an abnormal vestibule, and a large cochlear aqueduct. Of the remaining four children, hearing thresholds ranged from normal to profoundly decreased, but their HRCT scans were normal to visual inspection. When inner ear dimensions of these temporal bones were compared with norms established by Pappas and coworkers, however, seven of the eight ears had short cochleas and narrow lateral semicircular canals, and three ears had short or narrow vestibules. These results indicate that congenital cytomegalovirus infection may cause anomalies or growth disturbances of the temporal bone.

Child↗
PubMed1994

Intraoperative and postoperative electrically evoked auditory brain stem responses in nucleus cochlear implant users: implications for the fitting process.

Electrically evoked auditory brain stem responses (EABR) were measured in 12 adults and 14 children with the Nucleus cochlear implant. Measures were made both intraoperatively and several months following surgery. EABR thresholds were consistently greater than clinically determined measures of behavioral threshold (T-level) but less than maximum comfort levels (C-level). When the data were pooled across subjects and different stimulating electrodes, EABR thresholds were strongly correlated with both T- and C-levels. In subjects where both intraoperative and postimplant EABR measures were obtained, intraoperative EABR thresholds were consistently higher than postimplant thresholds. The electrophysiologic data have been incorporated into a practical procedure for programming the implant in young children.

Acoustic Stimulation↗
PubMed1994

Intraoperative measures of electrically evoked auditory nerve compound action potential.

A method for recording the electrically evoked whole-nerve action potential (EAP) at the time of cochlear implant surgery is described. Measures of EAP growth with stimulus level and functions describing the rate of recovery of the auditory nerve from the refractory state are reported for patients tested intraoperatively and for a group of patients using the ineraid implant, from whom recordings were made following implantation. Subjects tested intraoperatively were separated into three categories: congenitally deaf children (n = 14), prelingual meningitic children (n = 5), and postingual adults (n = 13). A fourth group consisted of postlingual adults (n = 14) tested postoperatively. Results from all groups showed a similar range of EAP growth and recovery rates across patients. Data from congenitally deaf children formed the exception showing steeper EAP growth functions than other subject groups. Electrically evoked whole-nerve action potential growth and recovery functions of the postoperative group of subjects showed modest correlations to speech perception scores measured after at least 18 months of implant use. The possible use of these measures in fitting an implant to an individual is discussed.

Adolescent↗
PubMed1994

Results of multichannel cochlear implants in congenital and acquired prelingual deafness in children: five-year follow-up.

Postlingually deafened children, using multichannel cochlear implants, have achieved substantial improvement in their speech perception abilities and, in many instances, the results are better than in postlingually deafened adults. It has been suggested that children with prelingually acquired and congenital deafness would not receive similar benefits, since they have not developed an auditory memory. The purpose of this study is to analyze the speech perception and production performance over time of prelingually deafened children who have been using a multichannel cochlear implant for 1-5 years. Preliminary results comparing the effects of age at implantation and etiology of deafness on performance are also examined.

Adolescent↗
PubMed1993

Multivariate predictors of audiological success with multichannel cochlear implants.

To predict the audiological outcomes of 2 multichannel cochlear implants, a preoperative battery of historical, audiological, electrophysiologic, and psychologic variables from 48 postlingually deafened adults was tested in a prospective randomized clinical trial. Multivariate analyses were used to select and combine these preoperative variables in a predictive index that was significantly related to audiological outcome at 9 months. The preoperative variables included in the predictive index were duration of profound deafness, speech reading ability, residual hearing, cognitive ability, measures of compliance and engagement with treatment, and use of nonverbal communication strategies. The preoperative predictive index had correlations of .81 with the Iowa Sentences Test, and .78 with the NU-6 word understanding scores, both obtained in a sound-only test. Probability and percentile curves generated from these data offer considerable optimism in forecasting the range of likely audiological outcomes that would be realized by postlingually deafened adult candidates for multichannel cochlear implants.

Adult↗
PubMed1993

Polymerase chain reaction amplification of DNA from archival celloidin-embedded human temporal bone sections.

A method was developed for fast and efficient isolation of DNA from formalin-fixed, decalcified, celloidin-embedded human temporal bone sections for subsequent use in polymerase chain reaction (PCR) DNA amplification. The method relies on the use of an enzymatic digestion with proteinase K to release and solubilize the patient's DNA from an individual 20- to 25-microns temporal bone section. The method described should be of great value to those investigators extracting DNA from archival individual human temporal bone sections for polymerase chain reaction assays of specific genetic alterations associated with temporal bone pathologies. The molecular characterization of viral infections, oncogenes, or other etiological agents of disease using PCR could provide important information regarding the etiopathogenesis of many auditory, vestibular, and facial nerve disorders, such as autoimmune hearing loss, congenital hearing losses, Meniere's disease, otosclerosis, or Bell's palsy.

Collodion↗
PubMed1993

Insertional trauma of multichannel cochlear implants.

Insertional trauma to the cochlea from three different multichannel cochlear implant electrodes was evaluated in a single-blind controlled study in fresh human temporal bones. Sixteen fresh human temporal bones were implanted with one of three types of multichannel electrodes (Symbion/InnerAid, Cochlear/Nucleus, or Storz/UCSF). Seven temporal bones were used as controls where a cochleostomy only was created. The temporal bones were evaluated histologically and cochlear histograms of the trauma were created. Although the three electrode designs caused damage which was unlikely to hinder implant performance, a distinct pattern of trauma was seen with each of the three electrode types. The least traumatic of the three electrode designs in this study was the Nucleus type. The degree of insertional trauma may be relevant to changing indications for insertion of cochlear implants as well as for patients with device failure who require reimplantation.

Basilar Membrane↗
PubMed1992

Undifferentiated small-cell neoplasm of the petrous apex. A case report.

We present a rare case of undifferentiated small-cell neoplasm involving the temporal bone petrous apex. The symptoms, physical examination, importance of roentgenographic findings, and pathologic findings are reviewed. While not absolutely conclusive, the collective evidence in this case supports a diagnosis of small-cell carcinoma of the lung with metastasis to the petrous apex. A discussion of temporal bone malignancies, their frequencies, and characteristics is included. To our knowledge, a review of the literature over the past 25 years reveals no other published cases of an undifferentiated small-cell carcinoma in the temporal bone.

Adult↗
PubMed1992

Performance over time of congenitally deaf and postlingually deafened children using a multichannel cochlear implant.

The speech perception performance of 10 congenitally deaf and 3 postlingually deafened children who received the Cochlear Corporation multichannel cochlear implant was examined and compared. The children were tested preimplant and at 6-month intervals up to 2 years using the Monosyllable-Trochee-Spondee test (MTS), the Word Intelligibility by Picture Identification test (WIPI), and Phonetically Balanced Kindergarten (PB-K) or Northwestern University List 6 (NU-6) word lists. The postlingually deafened children exhibited significantly improved performance on open- and closed-set tests of word recognition after 6 months of implant use, a pattern similar to that of postlingually deafened adult implant users. In contrast, the congenitally deaf children did not exhibit measurably improved performance on speech perception tests until after 12 months or more of implant use. With as much as 18-24 months of use, however, some congenitally deaf children demonstrated limited open-set word recognition.

Acoustic Stimulation↗