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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.

Many clinicians feel that single-channel cochlear implants are limited in the information they can provide. This has led to some common misconceptions regarding single-channel and multichannel systems. At the House Ear Institute, a growing number of children with the 3M/House single-channel implant are demonstrating open-set understanding of speech on measures designed to test such abilities in children. As a result, we have revised our thinking regarding the potential of this device.

Long-term experience with the single-electrode cochlear implant has shown this device to provide significant benefit with minimal risk to the deaf adult. Based on these findings, the decision was made to begin implanting children. As of September 1, 1982, 27 profoundly deaf children (ranging in age from 2.7 to 17.5 years) have received the cochlear implant. Tests results are consistent with those found in adults, and the children have adapted well to using the device. Of particular interest are the results observed in the preschool-aged children, eight of whom have been implanted. Two of these children have now had the implant for a year. Findings to date indicate that progress with the implant is initially slower for the preschool-aged child than for older children and adults. In time, however, similar results are attained. Ultimately the younger children adapt even better to the device. These preliminary results are encouraging, but only long-term experience with a large number of subjects will better determine the benefits of the cochlear implant for the preschool-aged child.

The decision to implant cochlear prostheses in children came after positive findings with deaf adults and the belief that the benefits of receiving sound far outweigh the potential risks involved. As of December 1981, 12 profoundly deaf children have received the single-electrode cochlear implant. Their ages range from 3.5 to 17 years. Test results are consistent with those of adults. Mean thresholds across the frequency range fall between 59-64 dB SPL. With the implant, these children can perform specific timing and intensity differentiations which could not be done with hearing aids. Their voices are quieter and more modulated, and the children are not quite as noisy with objects in the environment (eg, do not slam doors any more). This preliminary data demonstrates that implanting subjects under the age of 18 years is feasible.

Audiological data collected through June 1984 were analyzed for 126 children with the cochlear implant. Preimplant hearing aid results were compared to cochlear implant results at 6-month follow-up test intervals. Auditory thresholds to warble tones and speech stimuli, and auditory discrimination test scores were significantly better with the cochlear implant at all test intervals than preoperatively with a hearing aid. Electrical measurements were also monitored. Mean thresholds remained consistent over time. Electrical comfort levels increased slightly over time, indicating a widening of the electrical dynamic range. Results have been extremely encouraging. Some trends are beginning to develop, but more long-term data are needed to define the potential benefit of the implant in children.

Twenty-two profoundly deafened adults, implanted with the single-electrode cochlear implant, were involved in a study to observe the effects of cochlear electrical stimulation on the vestibular system. Previous investigators had found evidence that the implant might disrupt postural stability. As there had been no general complaints of dizziness or dysequilibrium by the implant subjects, a study was undertaken to replicate the earlier study and to compare the results to more standardized procedures. A Sono-postural Test was devised from the Ataxia Test Battery for the testing of balance with and without an auditory prosthesis. Electronystagmography was also performed on the subjects before and after surgery as a means of monitoring vestibular status over time. Results from the these tests indicate that the single-electrode implant does not disrupt the balance system to any significant degree. In fact, evidence indicates that postural stability may actually improve with the cochlear implant activated.

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.

Twenty-five children deafened by meningitis were compared with 10 congenitally deaf children on cochlear implant performance. All subjects had met the audiologic criterion of profound deafness as required for implant surgery. Twenty subjects in the meningitis group had some degree of ossification at the round window, and drilling was required for electrode insertion into the scala tympani. In six of these subjects, bone completely filled the scala. There was a significant relationship between extensive ossification and the etiologic pathogen Diplococcus pneumoniae, as determined by radiologic and surgical reports. Postoperative results revealed that all subjects could be electrically stimulated, except for one with extensive bone formation. On implant performance, the meningitis group demonstrated sound-field thresholds comparable to those of the group with congenital deafness but required significantly higher voltage settings. These findings suggest that even with extensive labyrinthine ossification caused by meningitic deafness, neural elements are present and can be stimulated if enough power can be safely provided.

While the cochlear implant provides only limited auditory information, profoundly deaf children continue to show significant gains in hearing performance and speech production abilities. The evidence has indicated that children receiving consistent auditory training demonstrate more progress with the implant than those children in less auditory-type environments. As a result, the House Ear Institute is developing extended training protocols to help optimize implant performance. A three-component framework is detailed to include: (1) the production/perception model, (2) a comprehension/bottom-up approach, and (3) strategical methods of delivery (multisensory versus unisensory). The purpose of such development is to integrate "hearing" into home, classroom, and individualized therapy settings to better facilitate growth in listening skills and speech development within a psycholinguistic context.

In recent years, the House single-electrode cochlear implant has proven to be a clinically feasible prosthesis for profoundly deaf adults. Based on these findings, the decision was made to begin implanting those children who could not benefit from hearing aids. As of August 1982, 23 profoundly deaf children (ranging in age from 3.4 to 17.5 yrs) have received the cochlear implant. The majority were deafened by meningitis. Results to date indicate that children demonstrate sound field thresholds and receive timing/intensity information comparable to that of adult implant patients. Results have been extremely encouraging, but only long-term experience will determine the ultimate benefit of the implant in children.

Introducing sound to the prelingually deaf adult presents a special challenge to those concerned with the rehabilitation of the deaf utilizing the cochlear implant. Twelve subjects with an early loss have undergone implant surgery and have been fitted with external stimulator devices. Eight of the 12 subjects are considered successful users. Electrical thresholds are comparable to those for the postlingually deaf. However, the prelingual subjects initially have a reduced tolerance for sound and often react differently than the postlinguals. The prelinguals do not always respond to the sensation as sound, but rather as a feeling or vibration in the head. However, like the postlinguals, the prelingually deaf report being able to respond to attention-getting sounds, such as horn-honks and their names being called; and voice quality changes have been noted. These subjects find music particularly enjoyable through the implant. In addition, they have reported feeling more independent, more social, and even less lonely.

This article presents a statistical analysis of factors which may be predictive of improved speech and audiologic performance for implanted children. Such findings provide some prognostic indicators for identifying children who may have greater potential for success with the implant.

Of 20 children who underwent cochlear implantation for profound sensorineural hearing loss secondary to bacterial meningitis, 14 had round-window and cochlear ossification at surgery. Preoperative polytomography demonstrated ossification in 11 of these. The incidence of ossification was highest after meningitis secondary to pneumococcal pneumonia. In only one of four children with severe ossification of the labyrinth was implant surgery unsuccessful. Preliminary results indicate that mild labyrinthine ossification is not a contraindication to cochlear implantation.

The single-electrode cochlear implant is undergoing clinical trials in children under Federal Food and Drug Administration regulations governing medical devices. Seven teams from around the United States are participating in this investigation as coinvestigators with the House Ear Institute. The clinical research program involves evaluation and selection for an implant surgery, basic guidance for fitting the device, and follow-up monitoring on a regular basis. As of December 31, 1984, 164 profoundly deaf children have received the cochlear implant. They ranged in age at time of surgery from 2 yr, 5 mo to 17 yr, 11 mo. The majority of children were deafened from bacterial meningitis (N = 98). The pertinent issues involved in the implantation of children include methods of investigation, impact of deafness, potential risks and benefits, and alternatives. While the use of the implant in children continues to be controversial, the evidence to date indicates that this prosthesis can provide significant benefit for a select population of profoundly deaf children.

Years of experience with the cochlear implant in profoundly deaf adults led to a decision to attempt to extend the benefits of this device to children. As of March 15, 1983, 43 deaf children ranging in age from 2.7 to 17.5 years have been implanted. Seventeen of these are children under 6 years of age. All had worn hearing aids but demonstrated little or no benefit from them. Auditory thresholds with the implant are significantly better than those obtained unaided and with hearing aids. Although a longer period of experience is required, the preschool-aged children can eventually make the same auditory discriminations as older children and adults. Long-term impact on speech and language development remains to be determined, but there is already evidence for significant improvement in these areas.

Objective: This study sought to determine which variables contribute to attainment of age-appropriate phoneme production skills in pediatric cochlear implant (CI) users between 4 and 8 years post-CI. Methods: Participants include 161 children with CIs enrolled in a longitudinal, multi-center project, the Childhood Development after Cochlear Implantation study. All received a CI by 5 years of age (M=2.4 years). Children completed the Goldman-Fristoe Test of Articulation (GFTA) between 4 and 8 years post-CI. Participants were grouped by attainment of age-appropriate production skills (GFTA<85: Below normal range; GFTA≥85: Within normal range) at 4 and 8 years post-CI. Error scores were computed for each child. Data were analyzed using a mixed-effects linear model utilizing all available GFTA data 4-8 years post-CI. Results: One-half of participants had normal phoneme production at 4 years post-CI. Number of errors across participant groups decreased from 21.3 at 4 years post- CI to 10.2 at 8 years post-CI. Presence of residual hearing at baseline (p<.01) and better language scores at baseline (p<.05) and 36 months post-CI (p<.0001) significantly related to better GFTA scores over the 4-8 year followup period. Children who scored <85 on GFTA at both 4 and 8 years post-CI had significantly less residual hearing, lower speech perception scores, and poorer language outcomes at baseline and 3 years post-CI relative to other participant groups. Conclusions: Pediatric CI users who attain age-appropriate speech production scores at 4 and 8 years post-CI likely derived benefit from hearing aids pre-CI because of useable residual hearing, with a subsequent language advantage from the outset. Children with CI without usable residual hearing or adequate language skills by 3 years post-CI have greater risk of persistently delayed speech production skills after implantation, and may require more therapeutic intervention and support to maximize communication outcomes. [ABSTRACT FROM AUTHOR]

Objectives: Most hearing parents of children born with severe to profound SNHL wish their children to acquire spoken language. A key question parents face after the HL diagnosis is to identify a habilitation program that will facilitate subsequent language development while contemplating treatment options such as CI. We studied this question using longitudinal data from a multi-center study. Methods: CI candidates (mean age 26m) were classified into 5 subgroups based on parent-reported communication modes in habilitation settings before CI: 1:American Sign Language (ASL) only (N=42); 2:auditory-verbal, auditory- oral, or cued speech only (ORAL, N=63); 3:concurrent ORAL and ASL (N=47); 4:ORAL and non-ASL signs or total communication (N=19); and 5:no reported habilitation or use of gestures only (N=16). Spoken language developments were tracked via the Reynell Developmental Language Scales from baseline to the 3rd post- CI annual follow-up, and the Comprehensive Assessment of Spoken Language annually thereafter. Core composite SS based on age appropriate core tests through the 8th year follow-up were analyzed using mixed-effects regression accounting for age at CI, family income, and cognitive screening, speech perception, and maternal sensitivity scores. Pragmatic language SS between 4- and 8 years post CI were analyzed similarly. Results : There was significantly different longitudinal trajectories in overall spoken language development between groups (p=0.02). Group 2 gained 1.2 points/year faster (p=0.0037) and group 4 gained 1.5 points/year faster (p=0.0105) in core composite SS over 8 years, while groups 3 and 5 were not statistically different, when compared to the group 1 (ASL only). Although similar between-group patterns were seen in pragmatic language SS 4-8 years post CI, the differences were not statistically significant. Conclusion: Parental report of enrollment into an ASL only habilitation setting before CI was associated with a slower rate of overall spoken language development post CI in comparison to other communication settings. [ABSTRACT FROM AUTHOR]