Consonant production in children receiving a multichannel cochlear implant.

Consonant production was investigated in 29 children participating in the federal Food and Drug Administration's clinical trials of the Nucleus WSP-III cochlear implant. Speech samples were collected preimplant and 1 year postimplant. A significantly greater number of children produced stop, nasal, fricative, and glide consonants postimplant. Voiced stop consonants were used by more children than the voiceless cognates; however, voiceless fricatives were used more than voiced fricatives. Visible places of articulation were used more frequently than less visible places of articulation. Comparisons to Smith's data (J Speech Hear Res 1975;18:795-811) revealed qualitative similarities but postimplant, quantitative differences were observed. Post hoc analyses of the data revealed some sounds were influenced more by an implant than other sounds and suggest the role of an implant upon spontaneous speech is complex.

Performance of postlinguistically deaf adults with the Wearable Speech Processor (WSP III) and Mini Speech Processor (MSP) of the Nucleus Multi-Electrode Cochlear Implant.

Seven postlinguistically deaf adults implanted with the Nucleus Multi-Electrode Cochlear Implant participated in an evaluation of speech perception performance with three speech processors: the Wearable Speech Process (WSP III), a prototype of the Mini Speech Processor, and the Mini Speech Processor. The first experiment was performed with the prototype and Wearable Speech Processor both programmed using the F0F1F2 speech coding strategy. The second experiment compared performance with the Mini Speech Processor programmed with the Multi-Peak speech coding strategy and the Wearable Speech Processor programmed with the F0F1F2 speech coding strategy. Performance was evaluated in the sound-only condition using recorded speech tests presented in quiet and in noise. Questionnaires and informal reports provided information about use in everyday life. In experiment I, there was no significant difference in performance using the Wearable Speech Processor and prototype on any of the tests. Nevertheless, six out of seven subjects preferred the prototype for use in everyday life. In experiment II, performance on open-set tests in quiet and noise was significantly higher with the Mini Speech Processor (Multi-Peak speech coding strategy) than with the Wearable Speech Processor. Subjects reported an increase in their ability to communicate with other people using the Mini Speech Processor (Multi-Peak speech coding strategy) compared with the Wearable Speech Processor in everyday life.

Pediatric performance with the Nucleus 22-channel cochlear implant system.

Results from 80 pediatric subjects with 12 months of experience wearing the Nucleus multichannel cochlear implant are presented. The data suggest that children demonstrate statistically and clinically significant benefit across a broad spectrum of abilities with the implant. Significant postoperative improvement was demonstrated by 66 percent (51 of 77), 63 percent (45 of 72), and 46 percent (27 of 59) of subjects tested on suprasegmental (prosodic), closed-set and open-set tests, respectively. Forty-nine percent of subjects tested improved when lipreading was combined with sound from the implant, compared with lipreading alone. Children who were deaf at an early age or who had longer duration deafness tended to demonstrate poorer performance on the more difficult perceptual tasks after 12 months of implant experience. However, preliminary evidence suggests that continued improvements by congenital and prelinguistic subjects over longer periods of time may reduce performance differences between subjects with early and later onset deafness.

Speech production performance in children with multichannel cochlear implants.

The purpose of this study is to report on five speech production protocols collected as part of the Food and Drug Administration's Clinical Trials for the Nucleus multichannel cochlear implant. Sixty-one children, ranging in age from 2.4 years to 17.8 years, participated. Speech measures included nonsegmental and segmental portions of the Phonetic Level Speech Evaluation, the Phonologic Level Speech Evaluation, speech intelligibility, and an experimental condition examining speech produced with the device turned on versus off. Seventy-seven percent of the children improved on at least one-third of the speech production measures. Significant improvements in the ability to imitate prosodic characteristics were observed for 31.1 percent of the children. Improvements in the ability to imitate speech sounds were found for 66.7 percent of the children. Examination of phonologic skills acquired during spontaneous speaking improved for 55.6 percent of the children. Speech intelligibility improved in 62.9 percent of the children after implantation. More centralized second formant frequencies were observed in vowels produced with the speech processor turned off, as opposed to on, in all 13 of the children tested on this protocol. Data from this study suggest a multichannel cochlear implant may assist many children in developing better speech.

Prosodic and segmental aspects of speech perception with the House/3M single-channel implant.

Four adult users of the House/3M single-channel cochlear implant were tested for their ability to label question and statement intonation contours (by auditory means alone) and to identify a set of 12 intervocalic consonants (with and without lipreading). Nineteen of 20 scores obtained on the question/statement task were significantly better than chance. Simplifying the stimulating waveform so as to signal fundamental frequency alone sometimes led to an improvement in performance. In consonant identification, lipreading alone scores were always far inferior to those obtained by lipreading with the implant. Phonetic feature analyses showed that the major effect of using the implant was to increase the transmission of voicing information, although improvements in the appropriate labelling of manner distinctions were also found. Place of articulation was poorly identified from the auditory signal alone. These results are best explained by supposing that subjects can use the relatively gross temporal information found in the stimulating waveforms (periodicity, randomness and silence) in a linguistic fashion. Amplitude envelope cues are of significant, but secondary, importance. By providing information that is relatively invisible, the House/3M device can thus serve as an important aid to lipreading, even though it relies primarily on the temporal structure of the stimulating waveform. All implant systems, including multi-channel ones, might benefit from the appropriate exploitation of such temporal features.

Nucleus 22-channel cochlear implant: preliminary observations.

A carefully designed study was undertaken in 1982 to evaluate the performance of individuals who received the Nucleus 22-channel cochlear implant. All patients were profound-totally deaf, adults with a postlingual onset of impairment. The preoperative evaluation, prosthesis fitting, training, and postoperative testing were consistent across clinics. Single-subject studies, where each patient acted as his/her own control, revealed that of the 37 subjects, 16-24 obtained significant improvement (P less than or equal to 0.001) on unpracticed, unfamiliar recorded speech tests from the Minimal Auditory Capabilities (MAC) Battery, when using hearing alone (no lipreading). In addition, virtually all patients showed improvement in recognition of speech material with lipreading. The data support the efficacy of a feature extraction coding system where specific formant and amplitude information are transmitted via direct electrical stimulation to the cochlea.

Auditory capabilities of single-channel cochlear implant patients. Etiologic considerations.

The clinical audiometric test results from 53 postlingually deafened adults using the House single-channel cochlear implant were analyzed according to cause of deafness (otosclerosis, ototoxic drugs, meningitis, and trauma). With the exception of one measure, the routine clinical tests did not show a relationship between cause of deafness and performance with the cochlear implant. These findings suggest that, clinically, the single-channel cochlear implant is a viable prosthesis for patients with a wide variety of causes of deafness.

Tone decay in subjects with the single-channel cochlear implant.

Tone decay was studied in a group of 17 profoundly deaf adults who have a single-channel cochlear implant. With direct electrical input through the subject's induction coil system, tone decay was evaluated at 125, 250, 500, 2 000, 4 000, and 16 000 Hz. Results indicated that as the intensity of electrical stimulation increased, the ability to perceive a continuous signal also increased for the majority of the subjects. All but 3 of the subjects were able to perceive the electrical signal at suprathresholds for 2 min. The 3 subjects who exhibited tone decay differed from the rest of the sample in several ways: (1) they became deaf at an earlier age; (2) they had more years of profound deafness, and (3) they had fewer years of cochlear implant and hearing aid use.

Audiological results with the cochlear implant.

Audiological test results from 135 adult, profoundly deaf, single-electrode cochlear implant subjects are presented. Unaided, aided, and cochlear implant warble-tone and speech detection thresholds have been analyzed, as well as word, word stress, and environmental sound discrimination scores. Results indicate that implant thresholds are significantly better than aided thresholds at all frequencies tested and for speech detection. Also, word, word stress, and environmental sound discrimination scores are all significantly better with the implant than with a hearing aid. Although the implant does not provide speech discrimination, subjects report that it does provide valuable speech and sound awareness, which aids in speechreading and voice monitoring. A small group of subjects has shown that an an implant in the poorer ear can also be successfully combined with a hearing aid in the better ear. The audiological test results clearly show that the implant is a viable alternative for the profoundly deaf.