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PubMed2005

Evaluation of bilaterally implanted adult subjects with the nucleus 24 cochlear implant system.

OBJECTIVE: To evaluate the speech perception benefits of bilateral implantation for subjects who already have one implant. STUDY DESIGN: Repeated measures. PATIENTS: Thirty adult cochlear implant users who received their second implant from 1 to 7 years with a mean of 3 years after their first device. Ages ranged from 29 to 82 years with a mean of 57 years. SETTING: Tertiary referral centers across the United Kingdom. MAIN OUTCOME MEASURES: Monosyllabic consonant-nucleus-consonant words and City University of New York sentences in quiet with coincident speech and noise and with the noise spatially separated from the speech by +/-90 degrees . RESULTS: At 9 months, results showed the second ear in noise was 13.9 +/- 5.9% worse than the first ear (p < 0.001); a significant binaural advantage of 12.6 +/- 5.4% (p < 0.001) over the first ear alone for speech and noise from the front; a 21 +/- 6% (p < 0.001) binaural advantage over the first ear alone when noise was ipsilateral to the first ear; no binaural advantage when noise was contralateral to the first ear. CONCLUSIONS: There is a significant bilateral advantage of adding a second ear for this group. We were unable to predict when the second ear would be the better performing ear, and by implanting both ears, we guarantee implanting the better ear. Sequential implantation with long delays between ears has resulted in poor second ear performance for some subjects and has limited the degree of bilateral benefit that can be obtained by these users. The dual microphone does not provide equivalent benefit to bilateral implants.

Adult↗

PubMed1994

Electro-oculographic findings pre- and post-cochlear implantation.

Vestibular symptoms following cochlear implantation are relatively rare, in spite of well-documented evidence of a significant surviving vestibular neuron population in profoundly deaf individuals. This report details the electro-oculographic (EOG) findings before and after insertion of the Nucleus 22-channel cochlear implant in 25 adults. These findings are correlated to the clinical course of these patients.

Adolescent↗

PubMed2002

Changing expectations for children with cochlear implants.

Seventeen students with cochlear implants who were between 5 and 11 years of age and attended the Moog Center for Deaf Education school program were tested just before exiting the program. The Moog program is an intensive oral program that provides very focused instruction in spoken language and reading. Children leave the program when they are ready for a mainstream setting or when they are 11 years of age, whichever comes first. All of the children demonstrated open-set speech perception ranging from 36% to 100%. On a test of speech intelligibility, all students scored 90% or better. On language and reading tests, compared with the performance of normal-hearing children their age, more than 65% scored within the average range for language and more than 70% scored within the average range for reading. These data demonstrate what is possible for deaf children who benefit from a combination of a cochlear implant and a highly focused oral education program.

Age Factors↗

PubMed1998

[Cochlear implant for non-deaf patients?].

BACKGROUND: Cochlear implants have proven to be the method of choice for postlingually deafened adults. The great success of this application requires discussion of the degree in which the indication for cochlear implantation should be expanded to include patients with residual hearing. METHOD AND PATIENTS: Following an initial discussion of the term deafness, we present the preoperative and postoperative results in five patients with residual hearing. These patients achieve a certain degree of speech recognition with their well fitted hearing aids. However, their aided speech intelligibility did not exceed 30% with the standardized Freiburg monosyllabic word test at 70 dB. In each case the worse hearing ear was treated with a cochlear implant. Speech discrimination in silence and noise are compared with the results of a group of postlingually deafened cochlear implant patients. RESULTS: The five patients are very satisfied with the cochlear implant and use the telephone to communicate with unknown partners. They score 100% in the standardized four-syllable number test above 55 dB and they document a loss of speech discrimination between 0 and 25% within the open-set monosyllabic word test. The mean increase of best monosyllable intelligibility by the cochlear implant over the hearing aids is 65%. Using the innsbruck sentence test the patients score 100% at 70 dB; with the Göttingen sentence test, the mean result is 75%. Their mean results in noise are also very good, 76% at 10 dBS/N and 57% at 5 dBS/N respectively. None of these patients use the hearing aid on the untreated, better hearing ear. CONCLUSION: A multichannel cochlear implant lead to a significant improvement of speech comprehension in these patients with residual hearing. We can successfully implant patients with minimal benefit of their well fitted hearing aids. Our group is too small to be able to define general selection criteria. For the time being we use as an audiological indication a open-set monosyllabic word intelligibility of not more than 30% at 70 dB with well fitted hearing aids.

Adolescent↗

PubMed1981

Multichannel cochlear implant. Preliminary results in man.

Cochlear implantations of multichannel electrode arrays have been recently undertaken at the University of California, San Francisco in several totally deaf investigational subjects. One patient was extensively tested with a psychoacoustical battery and is the subject of this communication. Speech testing with CID sentences and open sets of spondee words revealed that this totally deaf subject could achieve approximately 40 to 50% discrimination level with his implant device alone in the absence of visual cues. This represents the first time that speech discrimination has been definitely shown in a cochlear implant subject, and this result has important implications for the future of cochlear implantations.

Cochlear Implants↗

PubMed2001

Suprameatal approach: new surgical approach for cochlear implantation.

The conventional technique for cochlear implantation is via a mastoidectomy and posterior tympanotomy. An alternative approach for cochlear implantation is hereto described. The middle ear is entered through a suprameatal approach (SMA) bypassing the mastoid cavity. This surgical approach shortens the duration of the procedure to approximately one hour. The introduction of the cochlear implant electrode array involves drilling in the suprameatal region and the osseous portion of the external auditory canal at a safe distance from the anatomical position of the facial nerve. This prevents possible injury by direct trauma or drill overheating of the chorda tympani or facial nerves. We report 15 consecutive patients who were operated on using the SMA technique. No complications were encountered as a result of this surgical technique but further experience may be necessary.

Adult↗

PubMedDate not supplied

A pathway for information transmission to the inner ear. Application to cochlear implants.

The use of cochlear implants as an aid to neurosensory deafness is becoming an established procedure. The transmission of a processed speech signal is accomplished either transcutaneously via radiofrequency or percutaneously by connector coupling. Whereas the former is sensitive to electromagnetic interference, the latter increases the risk of infection. To overcome these disadvantages, an infrared (IR) system for transmission through the tympanic membrane was devised and tested. The transmitter/receiver consisted of an IR light emitting diode (LED; 920 nm) and a photovoltaic cell. The LED was placed inside the auditory canal of four dogs and the photovoltaic cell in the tympanic cavity over the cochlear promontory. A sinusoidal signal modulation was applied to the LED. The emitted signal was detected undistorted after crossing the tympanic membrane, with an average absorbance of 20%. High frequency cut-off was adequate for cochlear implant purposes and audio prosthetic devices in general. The authors conclude that the tympanic membrane may be used as a translucent sealed interface to transmit data in the audio range to the middle and inner ears, with small power loss, good frequency response, and immunity to interference.

Acoustic Stimulation↗

PubMed2003

Evaluating the function of phonetic perceptual phenomena within speech recognition: an examination of the perception of /d/-/t/ by adult cochlear implant users.

This study examined whether cochlear implant users must perceive differences along phonetic continua in the same way as do normal hearing listeners (i.e., sharp identification functions, poor within-category sensitivity, high between-category sensitivity) in order to recognize speech accurately. Adult postlingually deafened cochlear implant users, who were heterogeneous in terms of their implants and processing strategies, were tested on two phonetic perception tasks using a synthetic /da/-/ta/ continuum (phoneme identification and discrimination) and two speech recognition tasks using natural recordings from ten talkers (open-set word recognition and forced-choice /d/-/t/ recognition). Cochlear implant users tended to have identification boundaries and sensitivity peaks at voice onset times (VOT) that were longer than found for normal-hearing individuals. Sensitivity peak locations were significantly correlated with individual differences in cochlear implant performance; individuals who had a /d/-/t/ sensitivity peak near normal-hearing peak locations were most accurate at recognizing natural recordings of words and syllables. However, speech recognition was not strongly related to identification boundary locations or to overall levels of discrimination performance. The results suggest that perceptual sensitivity affects speech recognition accuracy, but that many cochlear implant users are able to accurately recognize speech without having typical normal-hearing patterns of phonetic perception.

Adult↗

PubMed1998

Cochlear implantation in children with inner ear malformations.

We performed a case study and intervention study, with follow-up of 1 to 5 years, in 4 children with inner ear malformations who underwent implantation of a multichannel cochlear implant (Nucleus, Cochlear Corporation) at ages 3 to 12 years. Malformations included a common cavity deformity, 2 incomplete partitions, and 1 case of isolated bilateral vestibular aqueduct enlargement. One child had a single-channel implant placed at 3 years of age, and this was exchanged for a 22-channel implant at age 9. One child had her implant placed at age 4.5 years, but due to complications from a cerebrospinal fluid (CSF) leak had the initial implant removed and replaced at age 5 years during repair of the CSF leak. Intraoperative findings included a CSF leak at the time of surgery in 3 patients. One patient contracted bacterial meningitis 7 months postimplantation that was thought to be secondary to acute otitis media in the unoperated ear. Bilateral CSF leaks were noted in the middle ear by a lumbar puncture radionuclide and fluorescein dye study. Successful repair of the CSF leaks and reimplantation of the cochlear implant was carried out in this patient. Mapping and programming of the implant was found to be challenging in each of these patients. All patients demonstrated improved performance after implantation. Two patients demonstrated some open-set speech perception. One patient demonstrates improved use of temporal cues in a structured closed set. One patient has achieved no significant speech recognition at this time, but does have improved sound detection and awareness. Cochlear implantation in children with congenital inner ear abnormalities can be a successful method of rehabilitation. It should be recognized that the postoperative speech perception results may be highly variable among patients, and that intraoperative complications may occur.

Cerebrospinal Fluid Otorrhea↗

PubMed1999

[Cochlear implantation in children with inner ear malformation and postoperative performance].

Cochlear implantation in children with cochlear malformation is on the rise. However, only one case has been reported in Japan. The objective of this paper is to report the authors' experiences with cochlear implants in children with cochlear malformations and, to investigate the morphological classification of cochlear malformation, surgical procedure, complications, and speech perceptions after implantation. Five children (6 ears, including 1 Usher's syndrome and 1 CHARGE association) with congenital inner ear malformations were implanted with multichannel cochlear implants (Nucleus Mini 22 device) between 1994 and 1998. Malformations included common cavity deformity 2, and incomplete partition 4. On the other hand, 4 cases with incomplete partition deformity underwent cochlear implantation by the transmastoid facial recess approach, 2 patients with common cavity deformity received implantation by the transmastoid labyrinthotomy approach. Complications such as facial twitching, cerebrospinal fluid (CSF) gusger, and flap-related problems were encountered. Facial twitching occurred in 1 of 2 patients with common cavity where the electrode array extended into the internal auditory canal. CSF gusher was encountered in 1 of 4 patients with incomplete partition, and revision surgery was performed one week later. One patient had delayed cochlear implant infection and a split pericranial flap was used to cover the defect in the skin flap. Within 6 months, however, the revised pedestal site broke down because of recurrent flap infection. Finally, the cochlear implant was explanted, and the patient underwent a new cochlear implantation in the contralateral ear. All the patients had satisfactory speech reception and word acquisition, but still poor phonetic expression.

Cerebrospinal Fluid Otorrhea↗

PubMed2004

Cochlear implantation in patients with substantial residual hearing.

OBJECTIVES: Cochlear implantation is an effective means for providing auditory rehabilitation in adult patients with severe to profound sensorineural hearing loss. It has been hypothesized that patients with substantial, preoperative residual hearing would be excellent cochlear implant candidates because of surviving neural populations and a lack of auditory deprivation. The purpose of this study is to describe the outcomes of patients with substantial residual hearing who have undergone cochlear implantation. STUDY DESIGN: Retrospective chart review of patients with substantial preoperative residual hearing who underwent cochlear implantation. METHODS: Chart reviews were completed for patients with substantial residual hearing who underwent cochlear implantation (City University of New York Sentence Test [CUNY] > 60%, Hearing in Noise Test sentences presented in quiet [HINTQ] > 50%, or Consonant-Nucleus-Consonant [CNC] > 20% in the ear to be implanted). Preoperative and postoperative measures of audiologic performance as well as complications were assessed. RESULTS: All 12 patients who met inclusion criteria ultimately surpassed their preoperative aided performance level after implantation and gained significant benefit from their cochlear implant. At 6 months postimplantation, mean CUNY, HINTQ, and CNC scores were 93%, 78%, and 48% in the implant ear alone, respectively. However, progress was slower than expected for many patients, and at least one patient took 1 year to surpass his preoperative performance level. There were no complications from surgery in this selected group of patients. CONCLUSIONS: Patients with some degree of residual hearing do benefit from cochlear implantation. However, there may be an initial decline in performance as compared with preoperative levels. This decline is overcome in time in this patient population. These patients need to be counseled accordingly.

Age Factors↗

PubMed1996

MRI and clinical decisions in cochlear implantation.

High-resolution computed tomography (HRCT) is the standard imaging technique used in cochlear implantation. However, cochlear and retrocochlear soft-tissue abnormalities may not be detected with HRCT alone. To determine whether magnetic resonance imaging (MRI) provides clinically significant information in addition to HRCT in the evaluation of candidates for cochlear implants, we performed a prospective study of 13 consecutive patients with cochlear implant patients receiving preoperative, high-resolution fast spin-echo T2-weighted MRI scans of the temporal bone. MRI identified unanticipated cochlear fibrosis in one patient, vestibular schwannoma in one patient, patency in the second turn of the cochlea in a patient with labyrinthitis ossificans, and disproved cochlear fibrosis suspected on HRCT imaging in one patient. These findings were significant for clinical decisions regarding candidacy for surgery, side selection for surgery, and surgical technique in cochlear implantation. Our experience suggests a high-resolution T2-weighted MRI of the temporal bone should be used preoperatively in addition to HRCT before cochlear implantation.

Adolescent↗

PubMed2003

Modeling open-set spoken word recognition in postlingually deafened adults after cochlear implantation: some preliminary results with the neighborhood activation model.

HYPOTHESES: Do cochlear implants provide enough information to allow adult cochlear implant users to understand words in ways that are similar to listeners with acoustic hearing? Can we use a computational model to gain insight into the underlying mechanisms used by cochlear implant users to recognize spoken words? BACKGROUND: The Neighborhood Activation Model has been shown to be a reasonable model of word recognition for listeners with normal hearing. The Neighborhood Activation Model assumes that words are recognized in relation to other similar-sounding words in a listener's lexicon. The probability of correctly identifying a word is based on the phoneme perception probabilities from a listener's closed-set consonant and vowel confusion matrices modified by the relative frequency of occurrence of the target word compared with similar-sounding words (neighbors). Common words with few similar-sounding neighbors are more likely to be selected as responses than less common words with many similar-sounding neighbors. Recent studies have shown that several of the assumptions of the Neighborhood Activation Model also hold true for cochlear implant users. METHODS: Closed-set consonant and vowel confusion matrices were obtained from 26 postlingually deafened adults who use cochlear implants. Confusion matrices were used to represent input errors to the Neighborhood Activation Model. Responses to the different stimuli were then generated by the Neighborhood Activation Model after incorporating the frequency of occurrence counts of the stimuli and their neighbors. Model outputs were compared with obtained performance measures on the Consonant-Vowel Nucleus-Consonant word test. Information transmission analysis was used to assess whether the Neighborhood Activation Model was able to successfully generate and predict word and individual phoneme recognition by cochlear implant users. RESULTS: The Neighborhood Activation Model predicted Consonant-Vowel Nucleus-Consonant test words at levels similar to those correctly identified by the cochlear implant users. The Neighborhood Activation Model also predicted phoneme feature information well. CONCLUSION: The results obtained suggest that the Neighborhood Activation Model provides a reasonable explanation of word recognition by postlingually deafened adults after cochlear implantation. It appears that multichannel cochlear implants give cochlear implant users access to their mental lexicons in a manner that is similar to listeners with acoustic hearing. The lexical properties of the test stimuli used to assess performance are important to spoken-word recognition and should be included in further models of the word recognition process.

Adult↗

PubMed2001

Tinnitus suppression in patients with cochlear implants.

OBJECTIVE: To determine the degree of tinnitus suppression provided by currently available multichannel cochlear implants and to determine factors that can influence this process. STUDY DESIGN: Prospective cohort. SETTING: Tertiary-care referral center. PATIENTS: Thirty-eight adult patients (18 years of age or older) with severe-to-profound hearing loss and tinnitus who met criteria for cochlear implantation. INTERVENTION: Cochlear implantation with a multichannel cochlear implant device. MAIN OUTCOME MEASURES: Patients rated the intensity of their tinnitus using a semiquantitative scale before and after cochlear implantation. These data were analyzed to determine the significance of the reduction of tinnitus after implantation. Tinnitus levels after implantation were also analyzed to determine whether the level of speech recognition, patient gender, or the implant type influenced the degree of tinnitus reduction. RESULTS: Statistical analysis revealed a significant reduction in tinnitus intensity in patients using cochlear implants, with 35 of 38 patients (92%) experiencing a reduction in tinnitus intensity. All multichannel implants studied afforded similar degrees of tinnitus suppression. The degree of tinnitus reduction was not correlated with speech recognition, as measured by CID Everyday Sentence scores. Female patients had significantly greater degrees of tinnitus before implantation, but both male and female patients demonstrated similar levels of tinnitus after implantation. No patient experienced greater levels of tinnitus after implantation. CONCLUSION: All currently available multichannel cochlear implant devices provide effective and similar levels of tinnitus suppression when activated. Exacerbation of tinnitus as a result of cochlear implantation does not represent a significant risk. The mechanisms by which cochlear implants exert tinnitus suppression are, as yet, unclear.

Adult↗

PubMed1991

Tinnitus suppression by cochlear implants.

The beneficial effects of cochlear implants on tinnitus have been noted in several studies, but few detailed appraisals of the phenomenon have been made. Six patients fitted with the UCSF/Storz cochlear implant device were studied. The effects of use of the implant device on tinnitus were monitored, and suppression of tinnitus was tracked throughout periods of stimulation and poststimulation. Tinnitus was effectively suppressed in five of six patients with the device on and with noise input, and reduction of perceived tinnitus loudness occurred in four of six with the device on but without acoustic input to the speech processor. Unilateral stimulation frequently resulted in bilateral tinnitus suppression. These studies reveal that profound tinnitus suppression is obtained by patients using their cochlear implants. Further work is required to quantify the optimal mode of stimulation, but these findings suggest that tinnitus sufferers may ultimately benefit from development of electrical stimulation tinnitus suppression devices.

Adult↗

PubMed1995

Results with the currently used cochlear implant.

Over the past 7 years we have implanted the Nucleus multichannel cochlear implant in 60 patients with severe hearing impairment. The postoperative speech recognition of adult postlingually deaf patients was satisfactory. Adult prelingually deaf patients exhibited poorer speech perception than postlingually deaf patients. However, some patients showed better results than expected. The prelingually deaf patients needed a longer rehabilitation period than the postlingually deaf patients. There was considerable variation in performance among the prelingually deaf patients. As for juvenile deaf patients, some showed good speech perception ability, but postoperative rehabilitation took longer. The cooperation of doctors, audiologists, speech therapists, schoolteachers, and family members was essential, and the creation of a cochlear implant center for children is desirable to obtain better rehabilitation. On the questionnaire given to the cochlear implant patients, some complained about their hearing in a noisy environment or while listening to television or music. The present cochlear implant system obviously needs further improvement.

Adolescent↗

PubMed1993

Pediatric cochlear implantation. Radiologic observations of skull growth.

We investigated the effects of long-term implantation of auditory prostheses on skull growth in young animals. Four monkeys were implanted with dummy cochlear implants at 6 months of age. To simulate implantation in children, the bed for the receiver-stimulator or interconnecting plug was drilled across a calvarial suture down to the underlying dura. Plain skull roentgenograms were periodically taken to monitor head growth for up to 3 years after implantation. These longitudinal measurements revealed no significant asymmetric skull growth. Postmortem measurements using computed tomographic scans confirmed these results and showed no significant difference in the intracranial volumes between the implanted and control sides of each animal or between experimental and nonimplanted control monkeys. These results suggest that long-term cochlear implantation in very young children will not cause any significant deformity of the skull.

Animals↗

PubMed1994

[Cochlear implants in children].

A multichannel cochlear implant was performed in 8 children, and the following results were obtained. The surgical procedures were not as difficult as in adults, and there were few postoperative complications. The results of testing postoperative speech comprehension ability were examined in three children whose course was followed for more than one year postoperatively. Some patients had good speech comprehension ability postoperatively, and we expect to continue performing cochlear implant in children. Postoperative rehabilitation takes longer. The cooperation of physicians, audiologists, speech therapists, school teachers and family members is essential, and establishing a cochlear implant center for children would be desirable.

Adolescent↗