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Results for “Cochlear Implants”

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PubMed2005

An evoked potential study of the developmental time course of the auditory nerve and brainstem in children using cochlear implants.

Central auditory responses to electrical stimulation from a cochlear implant were studied in 75 pre-lingually deafened children and 11 adults. Electrically evoked auditory brainstem response (EABR) latencies significantly decreased with duration of cochlear implant use and were not significantly affected by the age at implant activation. Significant decreases in early latency waves and interwaves occurred within the first 1-2 months of implant use, whereas longer term changes (6-12 months) were found for eV and eIII-eV, which measure activity in the more rostral brainstem. Comparisons to acoustically evoked auditory brainstem response (ABR) in children with normal hearing suggested shorter interwave EABR latencies, reflecting either distinct neural generators or increased neural synchrony, but similar rates of change in the later latency eV and eIII-eV with time in sound. In sum, normal-like development of the rostral auditory brainstem is promoted by cochlear implant use in children of a wide range of ages.

Adolescent↗

PubMed1992

Histopathology of the temporal bone following multichannel cochlear implantation.

The temporal bone histopathologic findings of a patient having received a Nucleus 22-channel cochlear implant (Cochlear Corp, Englewood, Colo) following bilateral transverse otic capsule fractures is presented. The case was complicated by perilymph fistulas, labyrinthitis, meningitis, and death due to drowning. The left cochlea revealed complete labyrinthitis ossificans; the implanted right cochlea demonstrated new bone formation in the basal turn of the scala tympani, degeneration of the organ of Corti, but normal ganglion cell counts. Results of psychophysical and speech perception 4 months after implantation are presented.

Adult↗

PubMed1997

Speech recognition with the MPEAK and SPEAK speech-coding strategies of the Nucleus Cochlear Implant.

The Spectra 22 Speech Processor and spectral peak (SPEAK) speech-coding strategy provide Nucleus 22 Channel Cochlear Implant (Cochlear, Corp., Englewood, Colo.) users with a better understanding of speech than the previous Mini Speech Processor and Multipeak (MPEAK) speech-coding strategy. On the NU-6 Monosyllabic Word Test, subjects scored 13% higher for words and 14% higher for phonemes with the SPEAK strategy than with the MPEAK strategy. On the Connected Speech Test and the CID Everyday Sentence Test, subjects scored 32% and 37% higher, respectively, with SPEAK than with MPEAK.

Adult↗

PubMed1990

Place coding of vowel formants for cochlear implant patients.

Four multiple-channel cochlear implant patients were tested with synthesized versions of the words "hid, head, had, hud, hod, hood" containing 1, 2, or 3 formants, and with a natural 2-formant version of the same words. The formant frequencies were encoded in terms of the positions of electrical stimulation in the cochlea. Loudness, duration, and fundamental frequency were kept fixed within the synthetic stimulus sets. The average recognition scores were 47%, 61%, 62%, and 79% for the synthesized 1-, 2-, and 3-format vowels and the natural vowels, respectively. These scores showed that the place coding of the first and second formant frequencies accounted for a large part of the vowel recognition of cochlear implant patients using these coding schemes. The recognition of the natural stimuli was significantly higher than recognition of the synthetic stimuli, indicating that extra cues such as loudness, duration, and fundamental frequency contributed to recognition of the spoken words.

Attention↗

PubMed1995

Acquisition of speech by children who have prolonged cochlear implant experience.

The four purposes of this investigation were to assess whether children acquire intelligible speech following prolonged cochlear-implant experience and examine their speech error patterns, to examine how age at implantation influences speech acquisition, to assess how speech production and speech perception skills relate, and to determine whether cochlear implant recipients who formerly used simultaneous communication (speech and manually coded English) begin to use speech without sign to communicate. Twenty-eight prelinguistically deafened children who use a Nucleus cochlear implant were assigned to one of three age groups, according to age at implantation: 2-5 yrs (N = 12), 5-8 yrs (N = 9), and 8-15 yrs (N = 7). All subjects had worm a cochlear implant for at least 24 mos, and an average of 36 mos. All subjects used simultaneous communication at the time of implantation. Subjects performed both imitative and structured spontaneous sampling speech tasks. The results permit the following conclusions: (a) children who have used a cochlear implant for at least 2 yrs acquire some intelligible speech; (b) children who receive a cochlear implant before the age of 5 yrs appear to show greater benefit in their speech production skills than children who are older, at least after a minimum of 2 yrs of use; (c) children who recognize more speech while wearing their cochlear implants are likely to speak more intelligibly; and, (d) signing does not disappear from a child's communication mode following implantation.

Adolescent↗

PubMed1999

Cochlear implantation for symptomatic hereditary deafness.

Recently, the effectiveness of cochlear implantation for hereditary deafness has been reported. We performed cochlear implantation for two patients with symptomatic hereditary deafness. Deafness in one patient was thought to be a result of albinism-deafness syndrome and in the other patient, a result of chronic progressive external ophthalmoplegia syndrome. Since their speech perception abilities improved dramatically, we believe that cochlear implantation should be actively performed for these two syndromes.

Adult↗

PubMed1995

Effects of talker familiarity on communication breakdown in conversations with adult cochlear-implant users.

This investigation had three objectives: a) to determine the types of repair strategies that cochlear-implant users implement to rectify communication breakdowns during ongoing conversation when talking to either familiar or unfamiliar communication partners, b) to determine how communication partners respond to particular types of repair strategies, and c) to describe the use of conversational behaviors that might circumvent communication difficulties. In Experiment 1, cochlear-implant subjects were videotaped while talking to familiar and then unfamiliar communication partners. In Experiment 2, a second group of cochlear-implant subjects were videotaped while speaking with an unfamiliar partner for 6.5 minutes. Analysis of the videotapes revealed that the cochlear-implant subjects in the two experiments most commonly asked "what?," "huh," or "pardon?" after not recognizing a spoken message (e.g., following a communication breakdown), regardless of whether the communication partner was familiar or unfamiliar. Communication partners' more common response to this repair strategy was to repeat the original message. When cochlear-implant subjects repeated back the segment of a message that they understood, communication partners most often confirmed or corrected them. When they requested information, communication partners usually provided it. The cochlear-implant subjects were more likely to use controlling conversational behaviors when interacting with unfamiliar than familiar communication partners. We conclude that repair strategy-response adjacency pairs may emerge during spontaneous conversations. Use of both specific and nonspecific repair strategies may indicate cochlear-implant users' adherence to a cooperative principle.

Adult↗

PubMed2004

[Beneficial effect of cochlear implants in the elderly].

OBJECTIVE: To evaluate the benefit of cochlear implantation in older adults aged 60 Years and over. METHODS: Fifty-six profoundly or totally hearing-impaired patients, aged 60 Years and over, were studied retrospectively. At the end of the preoperative evaluation, 28 patients received a cochlear implant. The mean age was 66 Years and the median follow-up was 22.5 Months. Speech perception scores before and after implantation were analyzed in order to evaluate the benefit of cochlear implantation. The speech perception score before implantation was compared to that of the non-implanted patients. RESULTS: There was a significant improvement of the dissyllabic words and sentences scores after implantation. The patients who are over 70 Years performed as well as those who are younger (between 60 and 70 Years). One patient developed a postoperative vertigo due a perilymphatic fistula. There was no flap-related problems. In the non-implanted group (mean age: 68 Years), 18 patients declined the cochlear device because they thought the subjective benefit of their hearing aid was sufficient and 5 patients declined because of surgical risk. The mean age, the cause and the duration of the deafness, and the speech perception scores were similar between implanted and non-implanted patients. CONCLUSION: This study demonstrates the beneficial effect of cochlear implantation in the elderly. These results suggest that a similar benefit could have been obtained in the patients who declined surgery. An early implantation could reduce the duration of the deafness and preserve binaural sound perception allowing increased performance in older people.

Aged↗

PubMed2006

Complications in children with long-term cochlear implants.

OBJECTIVES: To evaluate the complications in children who underwent cochlear implantation between 1991 and 2002 at Chi Mei Medical Center, Taipei Medical University. METHOD: The medical records of 169 cases of pediatric cochlear implants from 1991 to 2002 with a follow-up period of 3-11 years were reviewed for demographics and complications. A follow-up phone call and clinical visits were performed to determine the long-term results. RESULTS: The medical-surgical complications were facial nerve stimulation, transient dizziness, flap breakdown, minor change of taste, cholesteatoma, otitis media with effusion and mastoiditis. The device-related complications included 4 device failures and 1 device breakage in a traffic accident. CONCLUSION: Chronic otitis media and cholesteatoma developed in children as long-term complications and surgical challenges. Nevertheless, cochlear implantation surgery in children is a reliable and safe procedure with a low percentage of severe complications. To prevent cholesteatoma formation, parents are advised to schedule a regular ENT consultation at least yearly for early identification and treatment in the stages of acute otitis media or drum retraction.

Child↗

PubMed2000

Follow up of cochlear implanted handicapped children.

OBJECTIVE: To document progress and benefit of multi-handicapped children using cochlear implants. DESIGN: The evaluation of auditory responses to speech (EARS) test battery was performed on the children in this study at regular intervals following implantation. All children went through individually tailored intensive audiological rehabilitation programs following cochlear implantation. RESULTS: Individual results from ten multi-handicapped children receiving cochlear implants are presented in this paper. The majority of children in this study are successful implant users. Whenever possible, test scores are included as well as subjective case reports. CONCLUSION: Providing multi-handicapped children with cochlear implants can result in substantial benefit for both the child and parents. Multi-handicapped children are not contraindicated for cochlear implantation, although not all are considered to be good candidates.

Child↗

PubMed1997

Cochlear implant reimplantation.

The objective of this study was to determine whether insertion length and number of active channels remained the same after reimplantation of a cochlear implant. A retrospective case review of 170 consecutively implanted multichannedl cochlear implants was conducted. Seventeen of these devices had to be replaced. Data were analyzed for the Nucleus cochlear implant users who were reimplanted in the same ear. For most subjects, insertion length and number of channels remained unchanged, but a few subjects experienced substantial decreases. When the whole group was considered, a small but statistically significant drop was noted for both parameters. In conclusion, although reimplantation is technically possible, the first procedure provides the optimal surgical environment.

Adult↗

PubMed1990

[Cochlear implants].

William House gives in the address the essential of his philosophy about cochlear implant: "My 30 years of experience with cochlear implants has gone by very quickly. It is only during the past 10 years that cochlear implants have been widely used throughout the world. During that 10 years we have seen a change in the attitudes of scepticism and outright feeling of opposition to this technology to general acceptance and widespread interest. Implants are still in their infancy, and my present feeling is that it will take at least 20 years for this technology to reach maturity. I feel that we will only reach the ultimate maturity of cochlear implant technology if we keep a very open mind as to different types of devices and processing schemes, and if we try to keep our technology as simplified as possible in order to minimize our clinical time in working with these patients, and also minimize the cost of the manufacturing and maintenance of complex systems".

Adult↗

PubMed2004

Speech perception by students with cochlear implants using sound-field systems in classrooms.

Cochlear implants support deaf students' language development through the improved use of audition in the classroom. Unfortunately, the acoustics of typical classrooms greatly reduce auditory speech perception by these students. Sound-field systems can increase speech-to-noise ratios in classrooms and thus improve use of audition. These systems are used by 80% of students with cochlear implants who use an FM system in the classroom. The present study compares speech perception by 14 school-age cochlear implant recipients via 2 classroom sound-field systems, 1 wall-mounted and the other a personal, or desktop, system. Testing was conducted in 2 classroom environments, 1 noisy and reverberant (typical of many classrooms) and the other ideally quiet with reverberation of short duration. In the quiet room with low reverberation, both sound-field systems produced improved phoneme recognition, but there was no difference between the 2. In the noisy room with high reverberation, the sound-field benefits were greater, and the desktop systems provided more benefit than the wall-mounted systems.

Acoustics↗

PubMed2006

Monitoring of cochlear function during cochlear implantation.

OBJECTIVE: To report the feasibility of monitoring cochlear function during cochlear implantation. STUDY DESIGN: Case report. SETTING: Tertiary care referral center. METHODS: A child with audiologic features typical of bilateral auditory neuropathy underwent cochlear implantation. The scala tympani was entered inferior and slightly anterior to the round window membrane margin and smooth electrode insertion was achieved. Using single polarity click stimuli, the cochlear microphonic was measured at several steps during surgery. RESULTS: Cochlear microphonics were present at all stages during the implantation process and were clearly distinguished from neural responses by stimulus polarity inversion and constant latencies, despite changes in stimulus level. With the electrode in situ, amplitudes were smaller but persisted until the final measurement at 10 minutes after insertion. At follow-up 2 weeks after surgery, behavioral audiometry results indicated profound hearing loss in the operated ear. CONCLUSIONS: This paper demonstrates the feasibility of monitoring cochlear function during cochlear implantation. The routine surgical approach did not appear to adversely affect the functional measurements. Standard size, full electrode insertion did diminish the amplitude of the cochlear microphonics, possibly as a result of intracochlear mechanical impairment. Ultimately, profound hearing loss was documented, indicating that factors other than immediate changes induced by electrode insertion were likely responsible for the loss of cochlear function.

Cochlear Implantation↗

PubMed1998

[Measuring late electrically evoked potentials of the auditory system in cochlear implant patients].

The current adjustment of cochlear implant (CI) speech processors is based on a knowledge of the lower and upper limits (T- and C-levels) for electrical stimulus currents. These data are usually acquired from subjective classifications of individual patients. In cases with non-reliable patient responses, objective methods are necessary. Especially for the estimation of correct T-levels, auditory evoked potentials (AEP) can be applied, since they allow the determination of response thresholds in a frequency-specific manner. By determining the AEP of different latencies, late cortical responses can be registered almost without artifact contamination. These patients have been examined in 20 patients provided with 22- or 8-channel CI-systems (Nucleus or Med-EI implants). In all cases, clear responses and clearly discernible threshold transitions could be detected. By making use of acoustical stimulation in a free sound field, subjective hearing threshold and the T-levels of electrical stimulation could be verified. Since late responses are generated in the primary auditory cortex, their assessment permits a nearly integral functional control of the aided hearing system. To date, no problems have occurred from maturation or attentional effects in either pediatric or adult patients. The applicability in very young children remains to be explored.

Adult↗

PubMed1999

Cochlear implantation influences contralateral hearing and vestibular responsiveness.

A cochlear implant program has been carried out at the ORL Clinic of Semmelweis University in Budapest since 1985. Different devices and techniques have been used in pre- and postlingual children and adults. Over the last 6 years contralateral hearing improvement has been observed in 18 patients. This phenomenon can usually be demonstrated 6 months after the operation. Since our first observation several other authors have confirmed this phenomenon. However, the underlying mechanism is still obscure; both the efferent innervation and the plasticity of the brain may be important factors. The vestibular function of cochlear implant candidates was checked routinely pre- and postoperatively and changes in vestibular responsiveness were observed. Over the last 3 years air-caloric stimulation has been performed by means of a computer-based ENG system. In most patients the vestibular function was unchanged after the implantation. but in some cases a significant improvement in vestibular responsiveness was noted. Here we briefly describe cases of re-implantation carried out at the clinic. All the patients obtained better speech discrimination scores after having been implanted with intracochlear devices. None of the patients suffered any inner ear abnormality due to the first implant.

Adult↗

PubMedDate not supplied

Objective evaluation of vowel identification with the Digisonic cochlear implant.

Perceptual assessment of speech recognition performance with cochlear implants is confronted with problems raised by patients' availability and specificity. These problems can be avoided by using objective evaluation methods based on automatic classification of speech sounds. In the present report, different tuning strategies for the Digisonic cochlear implant were evaluated by discriminant analysis. The results presented here concern the correct classification of vowels. A set of 600 vocalic items, corresponding to 10 vowel categories and produced by 20 French speakers, were processed by the Digisonic DX10 with two different strategies. In the linear strategy, center frequencies of the 15 Digisonic channels were almost equally spaced in acoustic units (Hz). In the mel strategy, center frequencies were almost equally spaced in psychoacoustic units. For each strategy, energy levels of the frequency channels were quantified for each vocalic item and processed by statistical discriminant analysis for classification into 10 vowel categories. Results mainly show that the percent correct classification (PCC) is larger for the mel strategy and that the improvement is due to a higher concentration of frequency channels below 4 kHz. Implications of these results for the tuning of cochlear implants are discussed.

Adult↗

PubMed2004

Criteria of candidacy for unilateral cochlear implantation in postlingually deafened adults II: cost-effectiveness analysis.

OBJECTIVES: The objectives of this study were to estimate the cost-effectiveness of unilateral cochlear implantation for postlingually deafened adults; to study the impact on cost-effectiveness of relaxing criteria of candidacy to include patients who benefit from acoustic hearing aids; and to study the further impact of age at implantation and duration of profound deafness before implantation. DESIGN: This prospective cohort study was carried out in 13 hospitals with four groups of severely to profoundly hearing-impaired subjects distinguished by their preoperative ability to identify words in prerecorded sentences when aided acoustically. The groups represent a progressive relaxation of criteria of candidacy: Group I (N=134) scored 0% correct without lipreading and did not improve their lipreading score significantly when aided; group II (N=93) scored 0% without lipreading but did improve their lipreading score significantly when aided; group III (N=53) scored 0% without lipreading when the ear to be given an implant was aided but between 1% and approximately 50% when the other ear was aided; and group IV (N=31) scored between 1% and approximately 50% without lipreading when the ear to be given an implant was aided. Lifetime costs to the UK National Health Service of providing and maintaining a cochlear implant were estimated for each subject. The gain in health utility from cochlear implantation was estimated with the Mark III Health Utilities Index and was combined with life expectancy to estimate the number of quality-adjusted life-years (QALYs) that would be gained from cochlear implantation. Cost/QALY ratios were calculated by means of the Net Benefit technique and were compared with an upper limit of acceptability of 50,000 euros/QALY. RESULTS: Averaged over the whole cohort, the cost of gaining a QALY was 27,142 euros (95% confidence interval, 24,532 euros to 30,323 euros); 203 of 311 (67%) of the cohort displayed cost/QALY ratios more favorable than 50,000 euros/QALY. The average cost of gaining a QALY increased from group I (24,032 euros) to groups II (27,062 euros) and IV (27,092 euros) to group III (39,009 euros). Cost/QALY varied with age at implantation from 19,223 euros for subjects who were younger than 30 yr of age to 45,411 euros for subjects who were older than 70 yr of age. Cost/QALY was unacceptable because of minimal gain in health utility for the subset of groups I and II, who were given implants in ears that had been profoundly deaf for more then 40 yr and for the subset of groups III and IV, who were given implants in ears that had been profoundly deaf for more than 30 yr. CONCLUSIONS: Cochlear implantation was a cost-effective intervention for the majority of subjects, including the group given implants when older than 70 yr of age. Relaxation of criteria of candidacy for cochlear implantation reduces cost-effectiveness. Prioritization of the provision of cochlear implantation should take duration of profound deafness in the ear to be given an implant into account, as well as preoperative word recognition performance.

Adolescent↗