Programming features of the CLARION Multi-Strategy Cochlear Implant.

Because patient performance with multichannel cochlear implants varies widely, cochlear implant systems must address the diverse needs of patients during the postoperative fitting of the external equipment. This paper describes the processing strategies available with the CLARION Multi-Strategy Cochlear Implant and the different programming features available for optimization of these speech processing strategies. In addition, preliminary data are presented about the frequency of use of various fitting parameters with adult Simultaneous Analog Stimulation (SAS) and Continuous Interleaved Sampler (CIS) patients and pediatric CIS users. The data reveal that many of the programming features available to the clinician are useful with both the adult and pediatric populations and across strategies. The flexibility of both processing strategies and the programming options clearly contribute to the optimization of patient device fittings. Optimized device fittings, in turn, maximize patient performance.

Clinical trial of the CLARION cochlear implant in children.

Preoperative and postoperative efficacy results are reported for the first 58 children with 18 months of implant experience in the United States. A within-subjects repeated-measures design was used to compare preoperative performance with hearing aids to postoperative performance with the CLARION Multi-Strategy Cochlear Implant. The results revealed significant improvement over time on all speech perception measures. Higher scores and faster rates of progress were demonstrated by the children who used oral communication compared to children who used total communication, especially older children. The overall results suggest higher levels of performance and more rapid progress in the development of listening skills than has been reported in previous clinical trials with children. The latter finding appears to be due to advances in implant technology and changes in the demographic characteristics of the study groups.

Speech recognition performance of older children with cochlear implants.

HYPOTHESIS: The primary purpose of this study was to determine if children, > or =5 years old, with onset of deafness before the acquisition of spoken language (i.e., prelingually deafened) derived more benefit from multichannel cochlear implants than from conventional hearing aids. It was hypothesized that children who used oral communication (speech plus listening) would demonstrate higher levels of performance after implantation than children who used total communication (English sign system plus speech and listening). BACKGROUND: Previous research suggests that prelingually deafened children given implants at an older age derive limited benefit from these devices. Changes in candidacy criteria and advances in technology, however, may make cochlear implants a more viable treatment option for this group of patients. METHODS: A repeated-measures design was to used to compare patients' preoperative performance with hearing aids to postoperative performance with the CLARION cochlear implant after 3 and 6 months of device use. Pre- and postoperative performance were analyzed separately for children who used oral and total communication. RESULTS: Both groups of children (oral and total communication) demonstrated significant postoperative improvement on all outcome measures over time. Postoperative scores of the children who used oral communication were significantly higher than those of the children who used total communication on four of the five outcome measures. CONCLUSIONS: Prelingually deafened children who do not receive cochlear implants until > or =5 years of age derive significant benefit from current implant devices compared with that obtained with conventional hearing aids. The greatest benefit is derived by children who use oral communication, with much more limited benefit demonstrated by children who use total communication.

Use of a parent-report scale to assess benefit in children given the Clarion cochlear implant.

OBJECTIVE: To assess the auditory skills in everyday situations of prelingually deafened children with Clarion cochlear implants compared with hearing aids used preoperatively. STUDY DESIGN: The Meaningful Auditory Integration Scale (MAIS) was used to determine the preoperative and postoperative auditory skills of the children. RESULTS AND DISCUSSION: After implantation, the children showed improvement in three skill areas: bonding to the device, spontaneous alerting to sound in everyday situations, and ability to derive meaning from sound in the environment.

Speech recognition performance of pediatric Clarion patients.

OBJECTIVE: To evaluate the speech performance of children with the Clarion Multi-Strategy Cochlear Implant. PATIENTS: Prelingually deafened children who had received the Clarion implant. METHODS: The Spondee and Monosyllable Word Identification subtest of the Early Speech Perception test, the Glendonald Auditory Screening Procedure (GASP), and the Phonetically Balanced Kindergarten test (PB-K) were administered to subjects 3 and 6 months after implantation. RESULTS: At 3 months, subjects' performance was higher than preoperatively with hearing aids. At 6 months, performance improved further. Scores were higher on the ESP and GASP than on the PB-K. The scores indicate better levels of speech recognition than were obtained with older implant processing strategies. Subjects varied considerably in their performance. The results are preliminary because of the small sample.

Cochlear implantation of children with minimal open-set speech recognition skills.

OBJECTIVE: The purpose of this study was to evaluate the postoperative performance of 12 children who demonstrated some open-set speech recognition skills before receiving a Nucleus multichannel cochlear implant with a view toward expanding the selection criteria for cochlear implant candidacy to include children who derive minimal benefit from amplification. DESIGN: Pre- and postoperative performance of two groups of children were compared. Group 1 consisted of 12 children who demonstrated some open-set speech recognition skills before receiving a Nucleus multichannel cochlear implant (Borderline group). Group 2 consisted of 12 children who demonstrated no open-set speech recognition skills before implantation with a Nucleus device (Traditional group). In all children, candidacy was determined based on preimplant binaural aided performance. For most subjects, the poorer ear was selected for implantation. Mean pre- and postoperative speech recognition scores of the Borderline subjects were compared to determine the benefit provided by their cochlear implants. Secondly, matched-pair analyses were used to compare the mean speech recognition scores obtained by the Borderline and Traditional subjects. RESULTS: The scores of the Borderline group improved significantly on five of six speech recognition measures when 6 mo postoperative scores obtained with the implant were compared with preoperative test scores obtained with hearing aids. By the 12 mo postoperative interval, the scores of the Borderline group had improved significantly (p < 0.05) on all six measures. In contrast, scores obtained by the Traditional group had improved significantly on three of six measures at both the 6 and 12 mo postoperative intervals. Comparison of postoperative test scores revealed that the Borderline group scored significantly higher than the Traditional group on three of six measures at the 6 mo test interval and on six of six measures at the 12 mo test interval (p < 0.05). CONCLUSIONS: The findings of this study indicate that both groups derive significant benefit from their cochlear implants. Although the mean preoperative audiograms for the implanted ears did not differ significantly for the two groups of subjects, members of the Borderline group exhibited significantly better speech recognition skills than the Traditional group during the first year after implantation. These findings suggest that the increased auditory experience of the Borderline subjects positively influenced their performance with a cochlear implant. The authors advocate that the selection criteria used to determine pediatric cochlear implant candidacy be broadened to include consideration of children who demonstrate minimal open-set speech recognition skills.

Successful revision of failed cochlear implants in severe labyrinthitis ossificans.

Labyrinthitis ossificans may complicate the insertion of a multichannel cochlear implant in patients deafened after meningitis. Two children who initially underwent partial insertion of a 22-channel cochlear implant because of severe cochlear ossification required revision surgery after several months of unsuccessful device use. At the time of revision, resection of the car canal, tympanic membrane, malleus, and incus provided access to the lateral wall of the cochlea, permitting extensive drilling of the basal turn and a circumodiolar placement of the electrode. Functional integrity of the electronic components of the original device was documented intraoperatively, avoiding the expense of a new receiver-stimulator. Complete insertion of the active electrodes was accomplished in both cases, and electrophysiologic responsiveness to the implant was documented using intraoperative electrically evoked auditory brainstem response recordings. Postoperative performance has been similar to that of cochlear implant patients with nonossified ears. Experience with these two cases suggests that efforts to optimize electrode insertion at the original surgical procedure are appropriate and may help to avoid the disappointment of an unsuccessful cochlear implant.

Cochlear implantation in patients with cochlear malformations.

OBJECTIVE: To report operative findings, postoperative course, and postimplantation performance in patients with cochlear malformations who underwent cochlear implantation. DESIGN: Case study and intervention study (before-after trial). Minimum follow-up of 12 months; average follow-up of 24 months. SETTING: Academic tertiary referral center. PATIENTS: Six patients, including five children who underwent implantation at ages 3.5 to 13 years and one adult who underwent implantation at age 27 years. malformations included common cavity deformity (n = 1), cochlear hypoplasia (n = 2), and incomplete partition (n = 3). All patients with cochlear malformations who underwent implantation at the University of Michigan, Ann Arbor, are included, selected from a group of 196 patients so treated since 1986. INTERVENTION: Implantation with a standard multichannel cochlear implant. MAIN OUTCOME MEASURES: Operative findings described include round window and facial nerve anatomy and cerebrospinal fluid leak. Postoperative roentgenographic findings, electrode activation, and reason for non-use of electrodes were investigated. Standard tests of speech perception were used to compare preoperative and postoperative performance for each subject. RESULTS: Operative findings included round window abnormalities (three patients), anomalous facial nerve (one patient), and cerebrospinal fluid leak (three patients). No surgical complications occurred. A minimum of 10 electrodes were activated for all patients. Electrode thresholds and discomfort levels were variable for several months after implantation. All patients demonstrated improved performance after implantation. Four subjects demonstrated open-set speech perception. Two other subjects, whose poor language skills precluded administration of standard tests, showed increased awareness of environmental sounds and increased vocalization after implantation. CONCLUSIONS: Cochlear implantation can be a successful method of rehabilitation in patients with congenital deafness who have cochlear malformations.

Electrically evoked auditory brain-stem response in pediatric patients with cochlear implants.

OBJECTIVE: To study the feasibility and clinical applicability of preoperative, transtympanic electrically evoked auditory brain-stem response (EABR) in a pediatric patient population with cochlear implants. DESIGN: A descriptive study using repeated measures analyses of variance to determine if EABR measures were affected by response configuration or cochlear status. SETTING: The operating room before cochlear implant surgery. PATIENTS: A population-based sample of 43 patients aged 2.5 to 14.5 years who were candidates for cochlear implantation. INTERVENTION: Stimuli consisting of brief balanced biphasic current pulses were provided by a transtympanically placed promontory needle electrode; EABR was recorded with subdermal needle electrodes on the forehead and contralateral mastoid. MAIN OUTCOME MEASURE: Presence or absence of postoperative electrical excitability with a cochlear implant. RESULTS: Electrically evoked auditory brain-stem responses were available from 41 of the 43 patients tested. Mean EABR threshold was 406.5 microA (SD = 118.1) for 31 patients with patent cochleas and 472 microA (SD = 91) for 10 patients with cochlear ossification. Mean wave V latency at threshold was 4.69 milliseconds (SD = 0.57). CONCLUSION: Preoperative EABR is an integral component of the preoperative selection process for pediatric patients with cochlear implants.

Variables affecting implant performance in children.

This study examined the variables that contribute to the large individual differences in the speech perception skills of children with the Nucleus multichannel cochlear implant. Sixty-one children were tested on four measures of speech perception: two tests of closed-set word recognition, one test of open-set recognition of phrases, and one open-set monosyllabic word test, scored on the basis of the percentage of phonemes as well as words identified correctly. The results of a series of multiple regression analyses revealed that the variables of processor type, duration of deafness, communication mode, age at onset of deafness, length of implant use, and age implanted accounted for roughly 35% of the variance on two tests of closed-set word recognition, and 40% of the variance on measures that assessed recognition of words or phonemes in an open set. Length of implant use accounted for the most variance on all of the speech perception measures.

A comparison of round-window and transtympanic promontory electric stimulation in cochlear implant candidates.

We compared within-subjects electrical thresholds and dynamic ranges obtained with direct round-window and transtympanic promontory stimulation carried out preoperatively in 12 patients who were candidates for a cochlear implant. Square waves with frequencies of 50, 100, 200, and 400 Hz were delivered in a 50% duty cycle to both sites in each patient. With the exception of threshold at 50 Hz (promontory thresholds were lower than round-window thresholds), there were no statistically significant differences for either thresholds or dynamic ranges between the two sites of stimulation. There was a general trend for round-window thresholds to be lower and dynamic ranges larger, especially for the higher frequencies of stimulation. Mean threshold slopes for the two sites of stimulation were nearly identical.

Auditory performance of children with cochlear ossification and partial implant insertion.

The management of the profoundly deaf child with a cochlear implant poses a special challenge, particularly when total ossification of the cochlea is present. In this setting, insertion of an electrode array into a child's cochlea is often difficult. Our experience supports the feasibility of partial insertion of a multichannel implant into the basal turn of an ossified cochlea. Five children with ossified cochleae who had undergone partial implantation of a multichannel electrode were compared with the performance of matched controls who had full insertion of multichannel implants. No dramatic differences were detected during a 6- to 18-month follow-up period on selected test measures. These preliminary results suggest that active electrode number may exert a limited effect on performance with a cochlear implant. Drilling out the basal turn of an ossified cochlea in conjunction with partial insertion of a multichannel implant appears to be an acceptable surgical and rehabilitational alternative for placement of a cochlear implant prosthesis in children with complete cochlear ossification.

Effects of channel number and place of stimulation on performance with the Cochlear Corporation multichannel implant.

The effects of active channel number and place of stimulation on auditory-only performance with the Cochlear Corporation multichannel cochlear implant were investigated in seven subjects. A balanced crossover design was employed; subjects were initially programmed with either 10 basal or the full complement of 20 to 21 active electrodes. Following a 6-month period with the initial coding strategy, subjects were programmed with the alternate configuration, which they used for an additional 6 months. Auditory-only performance on suprasegmental, phoneme (vowel and consonant) open- and closed-set speech recognition was compared between the two electrode configurations. Additionally, performance with the first configuration and performance with the second configuration 3 days following programming were also compared. While a trend for increased scores was noted with 20 electrodes, especially with open-set speech recognition tasks, none of the differences between the two configurations reached statistical significance, as indicated by a Wilcoxon test. A comparison of performance at the end of the first 6-month period and 3 days following programming with the second configuration revealed a trend for reduced scores, especially on vowel tests. Overall, our results indicate that the feature extraction coding strategy associated with the Cochlear Corporation device allows patients to function well with only 10 basal electrodes and that speech recognition is only mildly affected initially when patients are programmed with a different encoding strategy.

Independent evaluation of the speech perception abilities of children with the Nucleus 22-channel cochlear implant system.

The performance of 28 children with the Nucleus multi-channel cochlear implant, who had used the device an average of 1.7 yr, was examined on a battery of speech perception measures. All children demonstrated better speech perception skills with the implant than they had in the preimplant condition with hearing aids. With the Nucleus implant, 61% of the children demonstrated some open-set speech recognition and another 14% demonstrated closed-set speech recognition. Scores on the tests were corrected for guessing and a hierarchy of test difficulty was developed. The results revealed systematic differences in performance as a function of perception task and test format. The results of regression analyses, which were performed to identify predictors of success, showed that communication mode made a significant unique contribution to the variance in performance among subjects on an open-set word recognition test. When the scores of the children who used oral or total communication were compared on the full battery of tests, however, there were few significant group differences.

Effects of preoperative electrical stimulability and historical factors on performance with multichannel cochlear implant.

We investigated the relationship between results of preoperative transtympanic electrical promontory stimulation, duration of deafness, postoperative implanted psychophysical results, and postoperative speech and speech sound recognition as indicated by a battery of five tests. Our subjects were 10 patients implanted with the Cochlear Corporation multielectrode implant, 1 year postimplantation, with a minimum of 17 active electrodes programmed in the bipolar + 1 mode. The results indicated that preoperative promontory thresholds, the slope of the threshold function, and the duration of auditory deprivation are excellent predictors of postoperative speech and speech sound recognition in the auditory (processor alone) mode. These results have significant implications for patient selection and counseling.

Cochlear implants in children.

The resources and areas of expertise necessary to establish and maintain a successful children's cochlear implant program is discussed. Insights based on experience with a pediatric patient population are presented.

Pediatric cochlear implant candidacy issues.

Children with progressive sensorineural hearing impairment represent a special challenge to the audiologist and the otologist. These are patients with some residual auditory abilities that deteriorate with time as the hearing loss progresses. No doubt, the unnecessary implantation of an ear that significantly benefits from amplification needs to be avoided at all costs. By the same token however, there appears to be no advantage to waiting an inordinate amount of time after the loss of functional auditory abilities before recommending implantation. At times when a complete loss is predictable, implantation may be advantageous before the onset of complete auditory deprivation. Steps the clinicians should take to manage these patients effectively are briefly summarized below: Implementation of rigorous and frequent audiologic monitoring. If, for instance, a significant progressive loss of hearing has occurred over a 6-month period, resulting in a complete absence of open-set speech recognition abilities in the auditory-alone mode with appropriate hearing aids, it is probably counterproductive to wait to the point of a complete absence of aided speech detection. Implantation at a critical point in time will prevent complete auditory deprivation. Parental counseling concerning various management strategies, such as use of vibrotactile devices, changing communication skills, and issues involving cochlear implants need to be undertaken early. Parents need to be involved in every phase of the evaluation process because they are the ones who make the final decision concerning the implantation of their child. Relatively early implantation should be considered in light of what is known concerning the effects of disruption in a child's linguistic, cognitive, and emotional development resulting from complete auditory deprivation.(ABSTRACT TRUNCATED AT 250 WORDS)