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Biomedical subjects

B J Gantz

Publications and source records attributed to B J Gantz.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Performance over time with a nucleus or Ineraid cochlear implant.

This investigation determined whether the audiological performance of cochlear implant users varied with experience. Thirteen Nucleus and 14 Ineraid subjects were evaluated at 1, 9, and 18 mo after cochlear implant connection. Ten Nucleus and five Ineraid subjects were tested at 30 mo. On average, the ability of the subjects to recognize words and phonemes in an audition-only condition improved during the first 9 mo, as did their ability to recognize spondees in noise. The phoneme scores continued to improve during the next 9 mo. Environmental sound recognition improved gradually; significant improvement from the 1 mo scores was not noted until 18 mo. About half of the subjects who demonstrated poor word recognition at 1 mo showed significantly improved percent word correct scores by 18 mo. The Nucleus and Ineraid subjects did not differ in their patterns of change over time. An information transmission analysis performed on the subjects' consonant confusion matrices showed relatively little change for the nasality and place features during the first 18 mo, and relatively large change for the voice, duration, and frication features. Most improvement in the feature scores occurred during the first 9 mo.

Cochlear Implants↗
PubMed1992

Avulsion of the anomalous facial nerve at stapedectomy.

Injury to the facial nerve in an anomalous location overlying the oval window at the time of stapedectomy has rarely been reported. The authors recently have encountered three patients with such injuries. The facial nerve was found at the time of reexploration to run directly over the oval window. A fourth patient was explored primarily for a conductive hearing loss and the same anomalous course was discovered. The purpose of this report is to alert the otologic surgeon to this rare but potentially catastrophic anomaly and to review the pertinent embryology and management of these malformations.

Adult↗
PubMed1992

Natural vowel perception by patients with the ineraid cochlear implant.

Vowel recognition was tested in 10 patients using the Ineraid cochlear implant. The vowels were produced by a male speaker in the context 'heed, hid, head, had, hawed, hood, who'd, hud' and 'heard'. Performance varied from 34 to 93% correct. A descriptive feature system for the vowels was determined from an acoustic analysis. An information transfer analysis of these features suggested that information about the first formant frequency, vowel duration and fundamental frequency was transmitted. Information about the second and third formant frequency was transmitted less well. A sequential information transmission analysis suggested that the features of the first formant and duration accounted for nearly 80% of the information transmitted. The fundamental frequency and second formant frequency information accounted for an additional 8%. Information provided by the third formant frequency was largely redundant.

Adult↗
PubMed1991

The nature of the epithelium in acquired cholesteatoma. Part 2. Cell culture.

The exact nature and role of the epithelial layer in cholesteatoma remains undetermined. The aim of this study was to investigate cholesteatoma epithelium and normal aural epithelia in common cell culture conditions. Samples of cholesteatoma, external meatal epidermis and middle ear mucosa were obtained, successfully grown in cell culture, and subcultured. No significant morphological differences were found between cholesteatoma and aural epidermis. The only differences noted were delayed onset of colony formation, and the need to subculture prior to the cultures becoming confluent in the cholesteatoma cultures. Further research is required to account for these differences in growth patterns.

Cell Count↗
PubMed1991

The nature of the epithelium in acquired cholesteatoma.

Monoclonal antibodies with defined specifications for individual cytokeratins were used to stain the epithelia of the external auditory meatus, the middle ear and cholesteatoma. The observed staining indicated that the epithelium of the external auditory meatus has a pattern of keratin expression typical of epidermis in general and the epithelium of the middle ear resembles simple columnar epithelia. The pattern of staining of cholesteatoma closely resembled that of the skin of the external auditory meatus.

Antibodies, Monoclonal↗
PubMed1991

Psychological predictors of audiological outcomes of multichannel cochlear implants: preliminary findings.

The purpose of this research was to determine whether psychological variables were associated with the variability that characterizes the audiological performance of recipients of multichannel cochlear implants. Twenty-nine consecutive recipients of multichannel implants participated in a preoperative psychological assessment and audiological follow-up assessments after 18 months of implant use. Experimental cognitive measures that assess an ability to rapidly detect and respond to features imbedded in sequentially arrayed information accounted for up to 30% of the variance in implant outcome, suggesting the importance of cognitive abilities in implant outcome. Standardized measures of intellectual ability, however, were not predictive of outcome. The Health Opinion Survey, a measure of participatory engagement, was also a significant predictor of audiological outcome. Overall, the results implicated the importance of several specific psychological factors in the audiological outcome of cochlear implants in postlingually deafened adult recipients.

Adult↗
PubMed1991

Psychological change following 18 months of cochlear implant use.

Consecutive recipients of multichannel cochlear implants participated in preimplant as well as 9-month and 18-month psychological evaluations. Before receiving a cochlear implant, psychological tests indicated that the implant recipients were more depressed, suspicious, socially isolated, lonely, and socially anxious than was the general population. After 18 months of implant use, there was a significant reduction in depression, loneliness, social anxiety, social isolation, and suspiciousness. These changes in psychological state did not correlate with improved performance on audiological measures. The data suggest that although cochlear implants can have a positive effect on the emotional and behavioral status of persons with acquired postlingual profound deafness, the psychological outcome of implants is not simply a function of the audiological benefit assessed with standardized speech-based audiological tests.

Cochlear Implants↗
PubMed1991

Aural rehabilitation.

Aural rehabilitation involves a complete evaluation of the communication deficits and needs of the hearing-impaired patient as well as the provision of counselling and therapy. This article describes listening-assistive devices, speech production, and audiovisual training. Issues related to educational placement and tinnitus also are reviewed.

Cochlear Implants↗
PubMed1990

Vestibular schwannoma presenting with sudden facial paralysis.

Facial paralysis is an unusual manifestation of vestibular schwannoma, and generally signifies an advanced stage of tumor growth. We describe a case of eighth-nerve schwannoma that presented initially with rapid-onset complete unilateral facial paralysis. At the time of operation the nerve was found to be electrically intact despite marked compression by tumor. The facial nerve was preserved and facial motion has partially recovered postoperatively. All unexplained persistent facial paralysis should be evaluated by magnetic resonance imaging with paramagnetic contrast enhancement.

Adult↗
PubMed1990

Relationships among loudness indexes in cochlear-implant patients.

The purpose of the experiment was to determine if the most-confortable-listening (MCL) levels and loudness-discomfort levels (LDLs) can be predicted from threshold measurements obtained from patients with cochlear implants using direct electrical stimulation. Psychophysical measurements of thresholds, MCLs, and LDLs with 125-Hz and 2000-Hz sinusoids were obtained from 16 patients with cochlear-implants 1 month after the connection of their ineraid processor (an auditory prosthesis). In general, the correlation coefficients among the loudness indexes obtained with a 125-Hz stimulus were similar to those for a 2000-Hz stimulus. Correlations between thresholds and MCLs were moderate, whereas correlations for thresholds and LDLs were fair. Correlations between MCLs and LDLs were high. This suggests that LDLs cannot be predicted from thresholds. On the other hand, these preliminary data suggest that MCLs may be reliably predicted from thresholds or LDLs to set the gain on a cochlear-implant processor.

Adult↗
PubMed1990

Intensity operating range measures as predictors of word-recognition ability in cochlear implant subjects.

The purposes of the experiment were to examine the appropriateness of pre- and post-implant intensity measures (thresholds, most comfortable listening level, and loudness discomfort level) as predictors of post-implant phoneme-recognition ability and to study the relationship between pre- and post-implant intensity measures. Pre-implant intensity measures were obtained on 16 subjects who were eventually implanted with either a Nucleus device (n = 8) or a Symbion device (n = 8). Phoneme scores on a NU-6 word list were obtained on these 16 subjects at 1 month post-implant. Post-implant intensity measures were also made on the 8 Symbion subjects at 1 month post-implant. The results showed that none of the pre-implant intensity measures correlated significantly with post-implant phoneme scores. In addition, pre-implant intensity measures did not correlate with the same post-implant intensity measures. However, post-implant MCLs and LDLs correlated significantly with phoneme scores as reflected by correlation coefficients that were larger than 0.8. These preliminary results suggest that although intensity measures may relate to phoneme-recognition ability, their use as predictive measures (as in pre-implant measures) for post-implant ability is questionable.

Acoustics↗
PubMed1989

Temporal bone computed tomography in the preoperative evaluation for cochlear implantation.

High resolution computed tomography of the temporal bone is performed routinely in the preoperative evaluation for cochlear implantation. A retrospective review was performed to determine the effect of these studies. The clinical significance was determined through consultation with the referring otolaryngologist and review of the operative reports. Twelve examinations were reviewed. Abnormalities were identified in 12 of the 24 ears examined (eight of 12 patients studied). In two patients the CT examination strongly influenced the selection of the ear to be implanted. In four additional cases information felt to be useful in preoperative planning was provided. Useful information related to potential complications with the mechanical insertion of the electrode apparatus. We conclude that temporal bone abnormalities are common in the population undergoing cochlear implantation and that high resolution temporal bone CT is essential in preoperative evaluation. The CT scan should be interpreted with adequate knowledge of the operative procedure to evaluate any possible barriers to the mechanical insertion of the internal components of the system.

Cochlear Implants↗
PubMed1989

Audiologic results following reimplantation of cochlear implants.

Five patients using cochlear implants experienced internal device failure 6 weeks to 4 years following implantation. All devices were removed and new electrodes inserted. Single-channel implants were replaced with multichannel systems in three patients, while the others received identical multichannel implants. The performance on a uniform battery of audiologic tests was the same or better with the second implant in all patients. Replacement of intracochlear electrodes did not induce clinically apparent degeneration of auditory performance in this series.

Adolescent↗
PubMed1989

Issues of candidate selection for a cochlear implant.

The cochlear implant has been successful in providing sound to deaf patients. A wide spectrum of results, from sound awareness to word understanding without lipreading, has been achieved. However, because of the unpredictable nature of the results, appropriate candidate selection is imperative. Medical and surgical criteria for treatment of adults and children are presented.

Age Factors↗