Faculty Bibliography

The course of the facial nerve may place it within the current field generated by an activated cochlear implant to produce incidental facial movement. We investigated the presence of facial nerve stimulation associated with cochlear implants in the VA Cooperative Study of Advanced Cochlear implants. Twelve of 82 patients enrolled in this study demonstrated facial nerve stimulation within 2 years of implant activation. Facial nerve stimulation in six patients with multiple channel implants (Nucleus or ineraid devices) either resolved spontaneously (n = 2), or was eliminated by deactivating basal (n = 2) or apical (n = 2) electrodes. Two of six patients with single-channel electrodes (3-M/Vienna devices) demonstrated facial nerve stimulation that resolved spontaneously (n = 2), resolved with lowering current output (n = 2), or was refractory to processor adjustment (n = 2). Intraoperative assessment in one of the refractory cases indicated that facial nerve stimulation resulted from current spread through the modiolus to activate the facial nerve. A variety of factors, including implant design, stimulus parameters, and local tissue impedances, may interact to produce incidental facial stimulation. Low-impedance pathways between the scala tympani and the modiolus may deserve increased recognition as an interactive factor in cochlear implant performance

The speech perception abilities of 15 patients were measured preoperatively using hearing aids and postoperatively using the Nucleus 22-channel cochlear implant over a period of 1, 2, or 3 years. Analysis of mean data revealed that, although the greatest amount of improvement in speech perception scores occurred between the preoperative and 3-month poststimulation evaluation, there was also significant improvement in perception of segmental features and open-set speech recognition over the 3-year time period. When individual patient data were examined, however, it was clear that these improvements were due, in large part, to the performance of a subset of patients who had measurable open-set speech recognition abilities at the time of their 3-month, poststimulation evaluation. Subjects who used the processing scheme that included coding of F1 showed significantly more improvement over time than subjects who used the original F0F2 processing scheme exclusively. It was concluded that open-set speech recognition ability at 3 months is an important prognostic indicator of continued improvement in speech perception abilities over time

The use of preoperative round window stimulation has been advocated for its possible predictive value in cochlear implant patients. We have attempted to correlate cause of deafness, preoperative radiologic study, and postoperative stimulability and performance with preoperative stimulation. Round window stimulation procedures consisted of measurements of electrical thresholds and comfort levels, gap detection, and temporal difference limen. Radiologic studies were performed using high-resolution computerized semi-axial and coronal tomography with 1.5-millimeter overlapping cuts. Patient performance was measured using a standard audiologic test battery. Sixteen postlingually, profoundly deaf adults who received the Nucleus multichannel cochlear implant were studied. All 16 patients who responded to preoperative stimulation had acceptable CT scans for the ear operated on and stimulated postoperatively with the prosthesis. The lowest level at which a patient could reliably detect a gap between two signals ranged from 10 to 150 milliseconds, which was not predictive. For the temporal difference limen task, the patients who could reliably identify the longer of two pulses when the difference was less than 100 milliseconds did achieve varying amounts of open-set speech discrimination postoperatively. In summary, results indicate that the preoperative psychoacoustic electrical stimulation test battery provides useful information in predicting postoperative performance

This article describes the use of principal components analysis to derive a composite score from a battery of 24 audiologic tests. The composite score is being used as the primary outcome variable in a clinical trial comparing the efficacy of three cochlear implant devices for people with bilateral, profound hearing loss. The first principal component from the within-class pooled variance-covariance matrix over four time periods was chosen to establish the coefficients for the composite score. This component accounted for 61% of the total variance of the 24 audiologic tests. The first principal component had its largest coefficients associated with the most difficult audiologic tests. The mean composite score of all patients improved over time; some patients showed dramatic improvement. The changes in the composite score over time were also closely related to subjective impressions of implant performance by the patient, audiologist, and otolaryngologist

Nine children received the Nucleus multichannel cochlear prosthesis. The preoperative evaluation consisted of assessments of auditory function, speech recognition, linguistic skills, and speech production. There were no surgical complications, and recovery in all patients was uneventful. The device was programmed 4 to 5 weeks following surgery, and all children were conditioned to the task. Postoperative training began immediately following device stimulation and is ongoing. Auditory skills and speech production scales were devised to monitor each child's progress. All children have shown varying degrees of improvement in auditory skills and speech production using the implant alone

The ability to perceive for suprasegmental and eight segmental speech pattern contrasts was measured on 16 adult cochlear implantees using the Nucleus multichannel prosthesis with either F0-F2 (n = 9) or F0-F1-F2 (n = 7) coding. The results of this study indicated the following: (1) The Nucleus device provided significant access to the majority of suprasegmental and segmental speech contrasts. (2) Both one- and two-format coding strategies provided good access to speech pattern contrasts. (3) Considerable intersubject differences in performance were observed, but there was no evidence to suggest that these were related to either processing scheme. (4) Although the accessibility of speech contrasts varied, the pattern of perceptual performance was interpreted in terms of an acoustic/phonetic hierarchy. (5) The Speech Pattern Contrast (SPAC) test appears to be a practical procedure for analyzing the perception of phonologically salient information about the suprasegmental and segmental components of speech

The reported telephone usage by cochlear implant recipients has become a major issue of controversy. Although patients and clinicians report good communication skills via the telephone, no standardized tests have been used and no quantifiable results have been reported. In an effort to determine the extent to which our better-performing patients can use the telephone, we established a clinical protocol to assess their ability to recognize speech, taking into consideration the problems inherent in telephone testing. Eight cochlear implant recipients were administered the NU-6 Monosyllabic Word Test and the City University of New York Topic Related Sentences under the following listening conditions: soundfield in a soundproof suite and via telephone within the hospital, locally, and long-distance. Twenty-three percent of the patients implanted at New York University Medical Center demonstrated a significant degree of telephone communication ability