Intratympanic gentamicin for the treatment of unilateral Meniere's disease.

OBJECTIVE: To determine the efficacy of intratympanic gentamicin instillation as treatment of incapacitating unilateral Meniere's disease, using a predetermined regimen with a fixed dose. STUDY DESIGN: A prospective study from a single institution between 1988 and 1998. METHODS: One hundred fourteen patients were enrolled in this study. Gentamicin (26.7 mg/mL) was administered three times daily for 4 consecutive days. The Committee on Hearing and Equilibrium Guidelines for Reporting Treatment Results in Meniere's Disease of the American Academy of Otolaryngology and Head and Neck Surgery (1985) were used. RESULTS: Comprehensive data were available for 90 individuals. Complete control of vertigo was achieved in 76 (84.4%), substantial control in 8 (9.0%), limited control in 2 (2.2%), and insignificant control in 4 (4.4%) patients. Disability scores at the end of 2 years were as follows: 76 patients (84.4%) had no disability, 5 (5.6%) had mild disability, 2 (22%) had moderate disability, and 7(7.8%) had severe disability. Caloric testing responses, as determined using electronystagmography, were as follows: 71% of the patients had an absent ice-water response, 16% had a positive ice-water response, and in 13% there continued to be present a bithermal response. Hearing was worse in 22 patients (25.6%), unchanged in 41 (48.2%), and improved in 22 (25.6%). CONCLUSIONS: Intratympanic gentamicin administration using this particular protocol is an effective treatment option for patients with disabling unilateral Meniere's disease. Hearing loss is a distinct possibility, and patients should be advised accordingly.

Prognostic indicators of speech recognition performance in adult cochlear implant users: a prospective analysis.

In a previously reported retrospective study of 32 prelingually and postlingually deaf adult Nucleus 22-channel cochlear implant users, multiple parameters were analyzed to determine which were predictive of postimplant speech recognition. Duration of deafness divided by age at implantation, and the psychophysical measures of 1) the threshold slope function (50 to 400 Hz) and 2) detection threshold at 400 Hz obtained preimplantation by means of a round window ball electrode were found to correlate most highly with postimplant performance. A more recent prospective study of 22 consecutive perilingually and postlingually deaf adult Nucleus users has reaffirmed the previous findings. Results revealed a highly significant correlation (r = .873, p < .0001, df = 20) between estimated and realized speech perception. In view of these findings, it would appear that there are variables that can be used preoperatively to predict perilingually and postlingually deaf adults' speech performance. The implications of these findings with respect to patient counseling and realistic expectations both for the patient and the implant team are obvious.

Electro-oculographic findings pre- and post-cochlear implantation.

Vestibular symptoms following cochlear implantation are relatively rare, in spite of well-documented evidence of a significant surviving vestibular neuron population in profoundly deaf individuals. This report details the electro-oculographic (EOG) findings before and after insertion of the Nucleus 22-channel cochlear implant in 25 adults. These findings are correlated to the clinical course of these patients.

Evaluation of a new spectral peak coding strategy for the Nucleus 22 Channel Cochlear Implant System.

Sixty-three postlinguistically deaf adults from four English-speaking countries participated in a 17-week field study of performance with a new speech coding strategy, Spectral Peak (SPEAK), and the most widely used strategy, Multipeak (MPEAK), both of which are implemented on wearable speech processors of the Nucleus 22 Channel Cochlear Implant System; MPEAK is a feature-extraction strategy, whereas SPEAK is a filterbank strategy. Subjects' performance was evaluated with an experimental design in which use of each strategy was reversed and replicated (ABAB). Average scores for speech tests presented sound-only at 70 dB SPL were higher with the SPEAK strategy than with the MPEAK strategy. For tests in quiet, mean scores for medial vowels were 74.8 percent versus 70.1 percent; for medial consonants, 68.6 percent versus 56.6 percent; for monosyllabic words, 33.8 percent versus 24.6 percent; and for sentences, 77.5 percent versus 67.4 percent. For tests in noise, mean scores for Four-Choice Spondees at +10 and +5 dB signal-to-noise ratio (S/N) were 88.5 percent versus 73.6 percent and 80.1 percent versus 62.3 percent, respectively; and for sentences at +15 dB, +10, and +5 dB S/N, 66.5 percent versus 43.4 percent, 61.5 percent versus 37.1 percent, and 60.4 percent versus 31.7 percent, respectively. Subjects showed marked improvement in recognition of sentences in noise with the new SPEAK filterbank strategy. These results agree closely with subjects' responses to a questionnaire on which approximately 80 percent reported they heard best with the SPEAK strategy for everyday listening situations.

Prognostic value of round-window psychophysical testing with cochlear-implant candidates.

The preimplant, psychophysical-test results obtained with a single-ball, round-window electrode for 32 peri- or postlingually deafened, adult, Nucleus 22-channel cochlear-implant users were analyzed and correlated with their postimplant, open-set, speech recognition performance. The results revealed that some preimplant measures do have value as predictors of speech recognition abilities in this group of subjects. All subjects used the MPEAK speech-coding strategy and had been using their device for at least 6 months. The psychophysical measures that were found to correlate most highly with postimplant performance included the detection threshold at 400 Hz and the threshold slope function from 50 to 400 Hz, with lower values associated with higher speech recognition. To a lesser extent, detection thresholds at 100 and 200 Hz, the dynamic range at 200 and 400 Hz, and the gap detection threshold at 100 Hz correlated with speech performance. As well, duration-of-deafness variables were found to correlate significantly with postimplant performance.

Subjective benefits reported by adult Nucleus 22-channel cochlear implant users.

A questionnaire was mailed to a consecutive series of 23 adult, postlingually deafened, Nucleus 22-channel, cochlear implant recipients and their relatives to evaluate subjective benefits of cochlear implantation. All implantees had used their device for a minimum of 6 months. Responses were received from 20 implantees (87%) and 17 relatives (74%). Substantial improvements were reported by the respondents in speech recognition with lipreading, voice quality, independence, and communication confidence. Slightly less benefit was noted in speech recognition without lip reading. Respondents noted an increased recognition of environmental sounds and a reduction in tinnitus. Overall, 85% of implantees and 94% of their relatives were moderately to very satisfied with the device, and most indicated that they would recommend the device for others. Satisfaction correlated well with independence and confidence. Poor correlations were found between satisfaction and objective scores of sentence recognition, both in audition-only and audition-plus-vision conditions.

Round window versus promontory stimulation: assessment for cochlear implant candidacy.

Electrical stimulation of the cochlea is a part of the preliminary evaluation protocol for cochlear implant candidacy at many centers. Typically, a transtympanic needle electrode is placed on the promontory of the ear under consideration and electrical current is presented to measure auditory percepts and psychophysical-electrophysiologic measures. Since 1984, we have used a ball electrode placed directly on the round window (via a tympanotomy) for stimulation, with 27 subjects being so tested to date. Nine additional subjects have had stimulating electrodes placed on both the round window and the promontory. Seven of these subjects yielded complete data. For measurements of threshold, maximum acceptable loudness level, and dynamic range, promontory testing mean values were higher than round window measurements. However, the differences were not significant.

The effects of sophistication on three threshold tests for subjects with simulated hearing loss.

Forty-five normal-hearing subjects were divided into three groups to determine the effects of listener sophistication on threshold estimates obtained with three commonly used tests for pseudohypacusis. A pure-tone Stenger test, speech Stenger test, and pure-tone delayed auditory feedback test were performed on each subject. The results indicate that increased sophistication levels allow subjects to simulate larger hearing losses on the two Stenger procedures. Sophistication level did not play a significant role in threshold determination with the delayed auditory feedback procedure, which was also found to be the closest indicator of true threshold.