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PubMed2003

[Registering event-related auditory potentials (P300) in patients with cochlear implants].

Event-related auditory evoked potentials can contribute to the evaluation of discrimination abilities of cochlear implant users. Auditory P300 potentials to a frequency contrast were obtained in six post-lingually deaf adults using a cochlear implant and in a control group of normal hearing subjects. The aim of this study was to investigate how these potentials were determined by the stimulation pattern of the cochlear implant. To visualise these stimulation patterns colour-coded plots (stimulograms) were calculated based on the stimulus and the fitting file of the individual subject as inputs. These stimulograms were used to evaluate the influence of various stimulation parameters on the stimulation contrast used in an oddball paradigm. The influence of discrimination difficulty on the P300 response is demonstrated.

Adult↗

PubMed2001

Perceptual "vowel spaces" of cochlear implant users: implications for the study of auditory adaptation to spectral shift.

Cochlear implant (CI) users differ in their ability to perceive and recognize speech sounds. Two possible reasons for such individual differences may lie in their ability to discriminate formant frequencies or to adapt to the spectrally shifted information presented by cochlear implants, a basalward shift related to the implant's depth of insertion in the cochlea. In the present study, we examined these two alternatives using a method-of-adjustment (MOA) procedure with 330 synthetic vowel stimuli varying in F1 and F2 that were arranged in a two-dimensional grid. Subjects were asked to label the synthetic stimuli that matched ten monophthongal vowels in visually presented words. Subjects then provided goodness ratings for the stimuli they had chosen. The subjects' responses to all ten vowels were used to construct individual perceptual "vowel spaces." If CI users fail to adapt completely to the basalward spectral shift, then the formant frequencies of their vowel categories should be shifted lower in both F1 and F2. However, with one exception, no systematic shifts were observed in the vowel spaces of CI users. Instead, the vowel spaces differed from one another in the relative size of their vowel categories. The results suggest that differences in formant frequency discrimination may account for the individual differences in vowel perception observed in cochlear implant users.

Adaptation, Physiological↗

PubMed1999

Cochlear implantations in Northern Ireland: an overview of the first five years.

During the last few years cochlear implantation (CI) has made remarkable progress, developing from a mere research tool to a viable clinical application. The Centre for CI in the Northern Ireland was established in 1992 and has since been a provider of this new technology for rehabilitation of profoundly deaf patients in the region. Although individual performance with a cochlear implant cannot be predicted accurately, the overall success of CI can no longer be denied. Seventy one patients, 37 adults and 34 children, have received implants over the first five years of the Northern Ireland cochlear implant programme, which is located at the Belfast City Hospital. The complication rates and the post-implantation outcome of this centre compare favourably with other major centres which undertake the procedure. This paper aims to highlight the patient selection criteria, surgery, post-CI outcome, clinical and research developments within our centre, and future prospects of this recent modality of treatment.

Adolescent↗

PubMed1999

Imaging for cochlear implants.

All patients in the Birmingham Cochlear Implant Programme underwent computerized tomography (CT) scanning and were assessed and images interpreted by the main author. Of the first 100 cases, 20 were considered to have abnormalities of the inner ears by CT imaging. It is concluded that the commonest abnormality was cochlear otospongiosis followed by labyrinthitis ossificans. Otospongiosis is well shown by CT which gives a good predicator of luminal patency. However, labyrinthus obliterans, although usually apparent on CT, is not reliably shown in all cases and T2 weighted magnetic resonance imaging (MRI) is better.

Cochlea↗

PubMed2002

Development of speech perception and production in children with cochlear implants.

The purpose of the present study was twofold: 1) to compare the hierarchy of perceived and produced significant speech pattern contrasts in children with cochlear implants, and 2) to compare this hierarchy to developmental data of children with normal hearing. The subjects included 35 prelingual hearing-impaired children with multichannel cochlear implants. The test materials were the Hebrew Speech Pattern Contrast (HeSPAC) test and the Hebrew Picture Speech Pattern Contrast (HePiSPAC) test for older and younger children, respectively. The results show that 1) auditory speech perception performance of children with cochlear implants reaches an asymptote at 76% (after correction for guessing) between 4 and 6 years of implant use; 2) all implant users perceived vowel place extremely well immediately after implantation; 3) most implanted children perceived initial voicing at chance level until 2 to 3 years after implantation, after which scores improved by 60% to 70% with implant use; 4) the hierarchy of phonetic-feature production paralleled that of perception: vowels first, voicing last, and manner and place of articulation in between; and 5) the hierarchy in speech pattern contrast perception and production was similar between the implanted and the normal-hearing children, with the exception of the vowels (possibly because of the interaction between the specific information provided by the implant device and the acoustics of the Hebrew language). The data reported here contribute to our current knowledge about the development of phonological contrasts in children who were deprived of sound in the first few years of their lives and then developed phonetic representations via cochlear implants. The data also provide additional insight into the interrelated skills of speech perception and production.

Age Factors↗

PubMed1997

Cochlear implants in children with congenital inner ear malformations.

OBJECTIVE: To describe clinical experiences with multichannel cochlear implantation in children with inner ear malformations, including surgical indications and techniques, imaging findings, and outcomes. DESIGN: A retrospective review of a series of 10 consecutive cases with a mean follow-up of 29 months, as well as a review of the literature. SETTING: Academic referral center. SUBJECTS: Ten children who underwent multichannel cochlear implantation for inner ear malformations. High-resolution computed tomographic scans demonstrated a common cavity deformity in 3, an incomplete cochlear partition in 4, and an enlarged vestibule in 1. Two had membranous anomalies as indicated by cerebrospinal fluid gushers at surgery, but the results of imaging were normal. INTERVENTION: All subjects received multichannel cochlear implants. Two subjects underwent mastoid obliteration at the time of implantation owing to preoperative recurrent meningitis or chronic otitis media with episodes of clinical mastoiditis. MAIN OUTCOME MEASURES: The 10 subjects were evaluated for electrode insertion and stability and auditory function for up to 7 years. RESULTS: All 22 electrodes are functional in each child with an incomplete partition, an enlarged vestibule, or a membranous anomaly. Of 3 subjects with common cavities, 2 had full insertion of electrodes and 1 had 16 electrodes inserted. All subjects had speech awareness thresholds detected at 25 dB or better. Three (75%) of the 4 subjects with at least 30 months of experience, including 1 subject with a common cavity, have developed open-set word recognition. CONCLUSIONS: Electrode insertion and hearing results in children with an incomplete partition, an enlarged vestibule, or a membranous anomaly are similar to those in children with normal cochleas. Specific surgical techniques are effective for children with a common cavity, and the results are less certain. Cerebrospinal fluid gushers were encountered frequently but were not difficult to control.

Adolescent↗

PubMed1988

Evaluation of decisions regarding candidates for cochlear implants.

Stepwise regression analysis was used to evaluate measures predictive of the selection of candidates for cochlear implants. Results of a comprehensive selection protocol were compiled for a group of 31 profoundly hearing-impaired adults undergoing intensive pre-selection evaluation. Data included: unaided audiologic; aided audiologic; vestibular; otologic; medical; radiologic; voice/speech; speechreading; psychoacoustic; and electrophysiologic parameters. The results of the Cochlear Implant Team's decisions concerning selections of patients for implants were compared with the predictive outcome of regression analysis. Ramifications for the construction of cochlear implant evaluation protocols are discussed.

Adult↗

PubMed2003

[Cochlear implants in children with enlargement of vestibular aqueduct].

OBJECTIVE: To describe the clinical experiences with multi-channel cochlear implantation in the children with enlargement of vestibular aqueduct. METHOD: Fifteen patients were diagnosed with enlargement of vestibular aqueduct and received multi-channel cochlear implantation at Beijing Tongren Hospital. A cochleostomy was performed for all patients by a standard facial recess approach to anterior inferior to the round window niche. RESULTS: (1) Most of the electrodes were totally inserted in the cochlear, and gusher appeared in 6 implantations. (2) No serious complications occurred after implantation. (3) All patients have auditory sensations after implantations. (4) The hearing threshold in this series were similar to that of the normal cochlear implantation (the average threshold was 30 dB). (5) The rehabilitation concept was developed by Rehabilitation Research Center for Deaf Children in Beijing and Beijing Tongren Hospital. The training sessions included sound detection, word discrimination, auditory comprehension and spoken language skill development. The abilities of speech discrimination and spoken language were improved comparing with that of pre-operation. Two of the patients could go to the normal school after implantations. CONCLUSION: The outcome of hearing rehabilitation for children with enlargement of vestibular aqueduct were similar to those children with "normal" cochlear structure followed the multi-channel cochlear implantation.

Adolescent↗

PubMed1986

The psychological assessment of cochlear implant patients.

The use of a cochlear implant (CI) to restore some acoustical input to patients with complete acquired hearing loss may be expected to result in changes in their psychological functioning. CI programmes should therefore include a careful psychological screening of all candidates and subsequent psychological assessments of patients who receive implants. Procedures used in the psychological assessment of CI candidates and patients outlined in the literature, as well as those used in the Royal Ear Hospital (REH) programme, are discussed. It is concluded that standard psychological tests of personality and intellectual functioning are of limited value in the screening of CI candidates and the postoperative evaluation of patients. It is proposed that more useful information be obtained by an analysis of the possible functional value of the implant to each individual candidate and by assessment of actual postoperative changes in the patient's behaviour. Unless an implant leads to improvements in the patient's psychosocial functioning, the device is unlikely to be used. Examples of this approach in assessing the REH candidates and patients are given.

Cochlear Implants↗

PubMed1988

[The monochannel Monomac and multichannel Minimac cochlear implants].

Monomac monochannel and Minimac multichannel cochlear implants bring to the remaining hearing fibers sound information that is previously converted into adequate electric signals. Both function at constant currents. The Monomac monocanal system possesses only one electrode implanted either inside or outside the cochlea and sends off sound of basic laryngeal rythm to all the nervous fibers. The Minimac is entirely numerical and sends off the whole of the sound information by splitting it into 15 frequency tracks, to 15 electrodes inserted within the scala tympani by means of an electrode-holder. Programming allows for selecting specific values from each frequency track and thus regulating the needed compression individually. Both these implants (Monomac and Minimac) work no conflictlessly but complementarily to each other because they answer different, well-defined clinical needs.

Cochlear Implants↗

PubMed2003

Cochlear implantation for tinnitus suppression.

A high prevalence of tinnitus in cochlear implant users has been demonstrated, but fortunately a large percentage of patients do report some degree of tinnitus suppression postoperatively. Improvements in the duration and intensity and the annoyance level and loudness of the perceived tinnitus postimplant have been demonstrated. The risk of worsening of the tinnitus percept after cochlear implantation is small.

Cochlear Implantation↗

PubMed2005

Acoustic analysis of the voice in pediatric cochlear implant recipients: a longitudinal study.

OBJECTIVE: To characterize inherent acoustic abnormalities of the deaf pediatric voice and the effect of artificially restoring auditory feedback with cochlear implantation. DESIGN: Inception cohort. SETTING: Academic referral center. PATIENTS: Twenty-one children with severe to profound hearing loss (15 prelingually deaf, 6 postlingually deaf) accepted into the cochlear implant program were followed for up to 6 months. Patients unable to perform the vocal exercises were excluded. INTERVENTIONS: Objective voice analysis was performed using the Computerized Speech Laboratory (Kay Elemetrics) prior to cochlear implantation, at the time of implant activation and at 2 and 6 months postactivation. Assessments were based on sustained phonations and dynamic ranges. MAIN OUTCOME MEASURE: Fundamental frequency, long-term control of fundamental frequency (vF0) and long-term control of amplitude (vAM) were derived from sustained phonations. The dynamic frequency range was derived from scale exercises. Formant frequencies (F1, F2, F3) were determined using linear predictive coding. RESULTS: Fundamental frequency was not altered by implant activation or experience (P = 0.342). With profoundly deaf subject, the most prevalent acoustic abnormality was a poor long-term control of frequency (vF0, 2.81%) and long-term control of amplitude (vAm, 23.58%). Implant activation and experience had no effect on the long-term control of frequency (P = 0.106) but normalized the long-term control of amplitude (P = 0.007). The mean frequency range increased from 311.9 Hz preimplantation to 483.5 Hz postimplantation (P = 0.08). The F1/F2 ratio remained stable (P = 0.476). CONCLUSION: In children, severe to profound deafness results in poor long-term control of frequency and amplitude. Cochlear implantation restores control of amplitude only and implies the need for additional rehabilitative strategies for restoration of control of frequency.

Acoustics↗

PubMed1998

[Cochlear implantation in a child with a "common cavity" cochlear malformation].

A nucleus multichannel 22-electrode cochlear prosthesis was successfully implanted into a 4-year-old girl with a cochlear "common cavity" deformity. Preoperative radiologic studies showed bilateral common cavity cochlear malformations but no narrow internal auditory canal. Because left common cavity was larger than the right common cavity, the patient underwent a left cochlear implant. The facial nerve was found on the promontrium and interfered with accessing the hypoplastic round window. The cochlear cavity was entered through the hypoplastic semicircular canal to prevent facial nerve injury. In the postoperative rehabilitation phase, the child was able to distinguish phonemes, and word identification had started.

Child, Preschool↗

PubMed2004

An animal model for cochlear implants.

OBJECTIVE: To test the feasibility of using the deaf white cat model of early-onset deafness. We studied the neuronal effects of prosthetic intervention with a clinical, "off-the-shelf" multichannel cochlear implant. METHODS: We placed cochlear implants in 5 deaf white kittens at age 12 and 24 weeks. The devices were activated and stimulated in the laboratory using a clinical speech processor programmed with a high-resolution continuous interleaved sampling (CIS) strategy for 8 to 24 weeks. Stimulus parameters were guided by electrically evoked brainstem responses and intracochlear-evoked potentials. Kittens were assessed with respect to their tolerance and general behavior in response to speech, music, and environmental sounds. RESULTS: Surgical complications were minimal, and kittens tolerated the experimental procedures well. Subjects were able to detect and respond to a specific sound played from a computer speaker. Electrophysiologic responses were reliably attainable and showed consistency with observed behavioral responses to sound. This experimental paradigm, using clinical devices, can be used in a practical research setting in cats. CONCLUSIONS: Deafness and other variations in neural activity result in many distinct changes to the central auditory pathways. Animal models will facilitate assessment of the reversibility of deafness-associated changes at the level of the neuron and its connections. Our observations of the feasibility of using clinical devices in animal models will enable us to simulate clinical conditions in addressing questions about the effects of "replacement" activity on the structure and function within the central auditory pathways in deafness.

Animals↗

PubMed1996

Auditory plasticity in cochlear implant patients.

Dynamic range (DR) of cochlear implant electrodes and speech recognition scores (SRS) were chronologically studied in 23 post-lingually deaf subjects over a period of one year. DR significantly increased over one year (ANOVA, p = 0.03). When DR was compared among three groups of electrodes which were located in the inferior, ascending and superior segments of the cochlear basal turn, that in the superior segment showed the largest increase (p = 0.001), followed by those in the ascending and inferior segments. Vowel and consonant recognition scores with auditory cue were best 6 months after operation and were maintained at the level for one year. Although the time course of improvement differed between DR and SRS, a significant positive correlation was observed at 12 months after operation. Improvement of SRS could be a result of a DR increase in the superior segment of the cochlea, which should convey pitch information over the mid-frequency region.

Adolescent↗

PubMed2006

Hearing-impaired children in the United Kingdom, IV: cost-effectiveness of pediatric cochlear implantation.

OBJECTIVE: To estimate the cost-effectiveness of pediatric cochlear implantation by conducting a cost-utility analysis from a societal perspective. DESIGN: In a cross-sectional survey, the parents of a representative sample of hearing-impaired children assessed the health utility of their child using a revised version of the Health Utilities Index Mark III questionnaire. Linear regression was used to estimate the gain in health utility associated with implantation while controlling for eight potentially confounding variables: average (4-frequency, unaided, preoperative) hearing level (AHL), age at onset of hearing-impairment, age, gender, number of additional disabilities, parental occupational skill level, ethnicity, and parental hearing status. The gain in health utility was accumulated to estimate the number of quality-adjusted life years (QALYs) that would be gained from implantation over 15 yr and over a child's lifetime. The incremental societal cost of implantation, calculated in euros at 2001/2 levels, was estimated by summing the incremental costs of implantation that are incurred in the health sector, in the education sector, and by the child's family. The cost-effectiveness of cochlear implantation was estimated by calculating the incremental societal cost per QALY gained and was compared with an upper limit of acceptability of 50,000 euros per QALY. RESULTS: The parents of 403 implanted children, and 1863 nonimplanted children, completed the health utility questionnaire. Higher health utility was associated with a more favorable AHL, an older age at onset of hearing impairment, female gender, having fewer additional disabilities, having parents with a greater occupational skill level, white ethnicity, and implantation. The gain in health utility associated with implantation was estimated to be higher for children with a worse preoperative AHL and who were implanted when younger. Over 15 yr, for a child implanted at age 6 with a preoperative loss of 115 dB, 2.23 QALYs were estimated to be gained, compared with a mean incremental societal cost of 57,359 euros, yielding a mean cost per QALY of 25,629 euros. Cost-effectiveness was more favorable: (1) when estimated over a child's lifetime rather than 15 yr, (2) for children with a worse preoperative AHL, and (3) for children who were implanted when younger. CONCLUSIONS: The mean cost of gaining a QALY for the children in the present sample falls within acceptable limits. The strategy of giving highest priority for implantation to children with the greatest loss of hearing, and who are younger, maximizes benefit for a given cost.

Age Factors↗

PubMed1984

Indications for and results of cochlear implants for total binaural deafness.

Extensive clinical investigation of the cochlear implant, both in adults and children, has provided evidence of significant benefit with relatively minimal risk. Work is in progress worldwide to develop improved cochlear implant devices. Meanwhile, an auditory prosthesis is now available for the profoundly deaf patient who could not be successfully treated in the past.

Cochlear Implants↗

PubMed2000

[Cochlear implantation in the adult and the child. Results of the Marseille experience between 1991 and 1999.

The rehabilitation of patients with profound bilateral deafness has been notable in the 1990s for the use of cochlear implantation. In 1991 a cochlear implantation programme was inaugurated by the ENT team at the Timone University Hospital, in partnership with the Public Assistance for Marseille Hospitals, allowing funding for six implants each year. This article presents the main results of this programme. Between March 1991 and November 1999, 94 patients with profound bilateral deafness were assessed. Forty patients (29 adults and 11 children) were thought to be unsuitable. To date 27 adults (4 with prelingual deafness) and 22 children have been rehabilitated using a cochlear implant. Patient selection was carried out by a multidisciplinary team. It has been possible to quantify the degree of deafness and the excitability of the auditory nerve in the adult, the cochlear permeability, and the motivation and personality of the patients. Postimplant evaluation has allowed us to study the various factors resulting from wearing an implant. In adults, testing was carried out using open lists. In children, education methods were added to perceptive, expressive and behavioural performance to arrive at a profile. The results are presented and discussed in comparison with those found in the literature.

Adult↗