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PubMed1998

Facial nerve stimulation from cochlear implants.

OBJECTIVE: To evaluate the incidence of facial nerve stimulation from cochlear implants and to better define the segment of nerve being stimulated and the causes of stimulation. STUDY DESIGN: Retrospective patient case review and a temporal bone dissection study. SETTING: A tertiary care setting. PATIENTS: All patients given a cochlear implant at the Hospital of the University of Pennsylvania. This encompassed only adult patients. INTERVENTION: All patients had surgical insertion of either a 3M single channel, Nucleus 22-channel, or CLARION multichannel cochlear implant. MAIN OUTCOME MEASURES: Demonstration of facial nerve stimulation with a cochlear implant and determination of affected electrodes; measurement of electrode location and distances between the labyrinthine segment of the facial nerve and the cochlea in temporal bone dissections: and determination of the relationship between the labyrinthine facial nerve and the cochlea using computed tomography evaluation. RESULTS: The overall incidence of facial nerve stimulation using all three devices was 14% (8 of 58). Otosclerosis and otosyphilis appear to be predisposing conditions to stimulation. The mid-cochlear electrodes, located near the labyrinthine facial nerve, appear to cause stimulation of the VIIth nerve most commonly. Computed tomographic evaluation of the bone between the labyrinthine fallopian canal and the cochlea may provide some indication of potential facial nerve problems. CONCLUSION: Facial nerve stimulation from the use of cochlear implants is more prevalent in patients with otosclerosis and otosyphilis. The labyrinthine segment of the facial nerve is the most likely area being stimulated in most patients. Preoperative computed tomographic evaluation may be beneficial in determining the possibility of this problem.

Adult↗

PubMed2005

Magnet displacement following cochlear implantation.

OBJECTIVE: To describe a rare complication of cochlear implantation, such as magnet displacement. STUDY DESIGN: Retrospective case review. SETTING: The study was conducted at the Sheba Medical Center, Tel-Aviv, Israel. PATIENTS: One child presented with an external coil attached to the skin anteriorly to the receiver/stimulator site (20 months after implantation) and another child was seen with a displaced magnet under the skin a few days after a head trauma (28 months after implantation). Both children were implanted with the Nucleus 24 device at the age of 2 years. INTERVENTION: Plain skull radiographs showed the dislocated magnet in both cases. Surgery for each child was limited to revision of the receiver/stimulator site and reinsertion of the magnet to its pocket. RESULTS: Intraoperative Neural Response Telemetry well displayed the responses of evoked potentials of the auditory nerve within the cochlea in both children. Postoperative auditory responses were as good as those measured before the complication. CONCLUSION: The displaced magnet can be successfully managed by a simple revision procedure. The possibility of magnet migration should be considered in cases of device malfunction. Two cases of magnet migration from its pocket after cochlear implantation are presented. The diagnostic and surgical method used for resolving this condition are described.

Child, Preschool↗

PubMedDate not supplied

Cochlear implant place psychophysics 1. Pitch estimation with deeply inserted electrodes.

Numerical estimation of pitch was performed by 8 adult subjects implanted with cochlear prostheses manufactured by Cochlear Limited. The electrode arrays had been inserted into the scale tympani to between one and one and a half turns of the cochlea. Using bipolar stimulation, the pitch estimates for each subjects showed an overall reduction with insertion depth of the stimulated electrode. However, for several subjects, after decreasing regularly for the more basal electrodes, pitch estimates showed an abrupt decrease, followed in some cases by a region of low pitch. Two of the subjects, implanted with a modified electrode array, the '20 + 2' which allowed monopolar in addition to bipolar stimulation, exhibited an abrupt decrease in pitch estimate with bipolar but not with monopolar stimulation. In these two subjects, for stimulating electrodes inserted more deeply than about three quarters of a turn, bipolar stimuli produced lower pitch sensations, and presumably more apical neural excitation patterns, than monopolar stimuli.

Adolescent↗

PubMed1993

Partial insertion of the nucleus multichannel cochlear implant: technique and results.

The goal of cochlear implant surgery is to insert the entire electrode array into the scala tympani. Incomplete insertion is usually attributable to the presence of new bone formation as a result of meningitis. Surgical techniques for dealing with obstruction include various degrees of drilling of the cochlea or alternative placement of the electrode array. We evaluated the postoperative performance of eight such patients implanted with the Nucleus multichannel cochlear implant at NYU Medical Center as well as data from adults and children nationwide. Scores ranging from marginal closed-set speech discrimination to 40 percent on open-set speech recognition tests were obtained. Surgical procedure, placement, and number of electrodes as well as number of channels in use affect the ultimate performance of these patients.

Adolescent↗

PubMed2005

Complications of paediatric cochlear implantation: experience in Izmir.

Surgery for cochlear implantation (CI) bears the risks of complication associated with all major surgery, in addition to the particular risks associated with implanting a foreign body into the peripheral auditory system. Here we present a retrospective study involving 227 cochlear implant operations in 205 children to evaluate the rate of intra- and post-operative complications. Complications were defined as major complications, requiring explantation of the device or further operation, causing a significant medical problem, or leading to any degree of facial paralysis or requiring additional hospitalization for treatment; or defined as minor complications, namely those that settled spontaneously, with conservative treatment, with local care and/or with medication alone. In our study there were 15 (6.6 per cent) minor and 28 (12.33 per cent) major complications. The most frequent minor complication was dizziness and vomiting (3.08 per cent), followed by transient hemifacial oedema (1.76 per cent), head pain (1.32 per cent) and mild ataxia (0.4 per cent). The most frequent major complication was trauma to the device (9.69 per cent), followed by cerebrospinal fluid (CSF) gusher (2.2 per cent) and facial paresis (0.4 per cent). All of the device trauma cases were re-implanted. There were neither any life-threatening complications nor any facial nerve paralysis in our implanted children. This study confirms that CI is relatively safe and that major complications are few and within acceptable limits.

Adolescent↗

PubMed2006

Central auditory development in children with bilateral cochlear implants.

OBJECTIVE: To examine the time course of maturation of P1 latencies in infant sequential and simultaneous bilateral cochlear implant recipients. DESIGN: Retrospective case series. SETTING: Pediatric collaborative cochlear implant program. PATIENTS: Four children who received bilateral cochlear implants prior to age 2 years. INTERVENTION: Cortical auditory evoked potential was completed to determine the latency of the P1 response in 4 children with bilateral cochlear implants. MAIN OUTCOME MEASURES: Longitudinal development of the latency of the P1 cortical auditory evoked potential in children who received bilateral cochlear implants prior to age 2 years. RESULTS: In 2 patients who received sequential bilateral implants, P1 latencies recorded from the first implanted ear were within normal limits after 3 to 6 months of implant use. By comparison, P1 latencies from the second implanted ear reached normal limits as early as 1 month after implant use. In 2 patients who received simultaneous bilateral implants, P1 latencies from both ears were also within normal limits in a very short time frame (ie, by 1 month poststimulation). CONCLUSIONS: Our data suggest a high degree of plasticity of the central auditory pathways after early bilateral implantation. We find that P1 latencies provide a clinically useful biomarker of central auditory system development in children after cochlear implantation.

Auditory Cortex↗

PubMed2006

Cochlear implantation with ipsilateral petroclival chondrosarcoma.

OBJECTIVE: To highlight a case of cochlear implantation in the setting of ipsilateral petrous apex chondrosarcoma. BACKGROUND: A patient with bilateral progressive hearing loss was incidentally found to have a destructive right petrous apex lesion on computed tomography before cochlear implantation. The patient had no associated symptoms and a magnetic resonance imaging scan was obtained, narrowing the differential diagnosis. A middle cranial fossa approach was performed for synchronous biopsy of the lesion and cochlear implantation. RESULTS: Frozen sections revealed a low-grade chondroid lesion, and a Med-El Combi 40+ cochlear implant with a split electrode array was inserted via the middle fossa. Final pathologic examination revealed a Grade I chondrosarcoma. The patient suffered no complications postoperatively and was followed-up over 5 years with serial computed tomographic scans and clinical examinations. No additional treatment was administered. Eighteen months postoperatively, the patient experienced episodic vertigo. There were no new findings on computed tomography, and the vertigo improved with a low-salt diet. Otherwise, the patient had excellent hearing results, and the lesion has not progressed under observation. CONCLUSION: The implications of observing low-grade chondrosarcomas in well-selected patients and the unique aspect of cochlear implantation on the affected side are discussed.

Acoustic Stimulation↗

PubMed2005

Sound localization and sensitivity to interaural cues in bilateral users of the Med-El Combi 40/40+cochlear implant system.

OBJECTIVE: The purpose of this study was to investigate sound localization in subjects bilaterally implanted with MED-EL COMBI 40/40+ cochlear implants. In addition, the sensitivity to interaural cues was assessed. METHODS: In the localization test (11 subjects), CCITT noise (500 ms, original and HRTF-filtered, 70/75/80 dB sound pressure level) was presented from one of seven loudspeakers between -90 degrees and 90 degrees azimuth. The subject had to indicate which loudspeaker the noise was presented from. Sensitivity to interaural level differences (ILD) was assessed by performing localization tests (4 subjects) with the loudness of the two speech processors unbalanced to various degrees. To investigate the subjects' sensitivity to interaural time differences (ITD), lateralization was measured (7 subjects) as a function of the time difference between two Gaussian-like pulses, each directed to one of the subject's speech processor microphones by way of headphones. RESULTS: The judgments of all subjects significantly correlated with the positions of the loudspeakers. The scatter in the judged azimuth measured by the standard deviation of the responses was on average 27.5 degrees . Unbalanced loudness of the speech processors produced a bias in azimuth toward the speech processor with the louder volume setting. The mean rate of shift was 1.4 degrees per unit on the Wuerzburg loudness scale. Six of seven subjects showed a significant sensitivity to ITDs with the approximate time difference required for complete lateralization being 1,200 micros on an average. The one subject not showing a sensitivity to ITDs performed worst in the localization test. CONCLUSIONS: Bilateral cochlear implantation can restore spatial hearing in cochlear implant users. Both ILDs and ITDs are used by bilateral cochlear implant users in sound localization with ILDs appearing to be the dominant cue.

Adolescent↗

PubMed1986

Speech performance by patients with multichannel cochlear implants.

Thirteen patients were implanted with multichannel cochlear implants between April 1, 1984 and February 25, 1985. The patients are fitted with the sound processor unit 4 to 6 weeks postsurgery. One patient had a single-channel unit replaced with a multichannel implant. She reported improved sound quality. All patients use their implants daily and all patients would undergo implantation again (based on their current performance). Evidence exists that continued use leads to improved performance. Patient S.S. progressed from auditory-only scores of 12% and 24% to 100% in 4 months. The average open set auditory-only performance of six patients in the first 4 months on a spondee word list was 22%. The average of eight patients--more than 4 months post sound processor--is 44%, indicating improvement with use. Patients perform better when combining auditory input with visual input than they do with lip reading alone. The multichannel implant is well tolerated and accepted, and results in speech performance improvement.

Adult↗

PubMed2005

Noise susceptibility of cochlear implant users: the role of spectral resolution and smearing.

The latest-generation cochlear implant devices provide many deaf patients with good speech recognition in quiet listening conditions. However, speech recognition deteriorates rapidly as the level of background noise increases. Previous studies have shown that, for cochlear implant users, the absence of fine spectro-temporal cues may contribute to poorer performance in noise, especially when the noise is dynamic (e.g., competing speaker or modulated noise). Here we report on sentence recognition by cochlear implant users and by normal-hearing subjects listening to an acoustic simulation of a cochlear implant, in the presence of steady or square-wave modulated speech-shaped noise. Implant users were tested using their everyday, clinically assigned speech processors. In the acoustic simulation, normal-hearing listeners were tested for different degrees of spectral resolution (16, eight, or four channels) and spectral smearing (carrier filter slopes of -24 or -6 dB/octave). For modulated noise, normal-hearing listeners experienced significant release from masking when the original, unprocessed speech was presented (which preserved the spectro-temporal fine structure), while cochlear implant users experienced no release from masking. As the spectral resolution was reduced, normal-hearing listeners' release from masking gradually diminished. Release from masking was further reduced as the degree of spectral smearing increased. Interestingly, the mean speech recognition thresholds of implant users were very close to those of normal-hearing subjects listening to four-channel spectrally smeared noise-band speech. Also, the best cochlear implant listeners performed like normal-hearing subjects listening to eight- to 16-channel spectrally smeared noise-band speech. These findings suggest that implant users' susceptibility to noise may be caused by the reduced spectral resolution and the high degree of spectral smearing associated with channel interaction. Efforts to improve the effective number of spectral channels as well as reduce channel interactions may improve implant performance in noise, especially for temporally modulated noise.

Acoustic Stimulation↗

PubMed1998

Cochlear implantation in the deaf-blind.

OBJECTIVE: This study aimed to examine the outcome and rehabilitation of cochlear implantation in a select group of individuals: the deaf-blind. STUDY DESIGN: The study design was a retrospective and prospective case evaluation of the deaf-blind implantees. SETTING: The study was conducted at a national adult and pediatric cochlear implant center. PATIENTS: A total of eight adult and two pediatric blind or visually impaired individuals undergoing cochlear implantation for severe or profound deafness participated. Evaluation of the history, etiology of blindness and deafness, and outcome of the cochlear implantation was examined. INTERVENTIONS: Cochlear implantation and subsequent rehabilitation were performed. MAIN OUTCOME MEASURE: Bamford-Kowal-Bench (BKB) sentence scores were measured. RESULTS: Individually and as a group, these patients respond exceptionally well to cochlear implantation. The BKB scores are above the average for the sighted cochlear implantees. This raises the question of heterosensory substitution. CONCLUSIONS: Cochlear implantation has a major role to play in the rehabilitation of certain deaf-blind individuals, and these patients may be among the most worthwhile to consider for implantation. The implant team must acquire additional rehabilitative skills, and the strength of the deaf-blind culture must be taken into consideration.

Adolescent↗

PubMed1996

Correlates of cochlear implantation, 1986-1992.

There is a paucity of information regarding the use of cochlear implants within large populations. This article describes correlates of cochlear implantation procedures using a statewide hospital discharge database. Among the 146 implant procedures, 55% involved female patients, whereas the largest groups of patients were represented by younger and older persons (27% between ages 2 and 9 years and 24% 60 years and older). A bimodal distribution was apparent for average annual age-specific rates of cochlear implantation, with the highest rates among persons aged 2 to 9 years (5.4 implants per 1 million) and persons aged 60 to 69 years (3.7 implants per 1 million). Total hospital charges, excluding professional fees, exceeded $12,000 per implant and were found to vary significantly when examined by length of stay and by calendar year of procedure. The data presented are unique with regard to the total number of cochlear implant procedures included and the large, diverse population used. This study expands knowledge concerning the epidemiology and utilization of cochlear implantation.

Adolescent↗

PubMed2005

Cochlear implantation at under 12 months: report on 10 patients.

OBJECTIVES: There is growing evidence that early application of a cochlear implant in children affected by profound congenital hearing loss is of paramount importance for the development of an adequate auditory performance and language skills. For these reasons and as a result of advances in audiologic diagnosis and an enhanced awareness of the safety of cochlear implants, the age of implantation has substantially decreased over recent years. Children aged as little as 12 months are now being implanted in some centers. On the basis of our experience with very young children, we believe that the date of implantation may be further reduced to only 4 to 6 months of age. STUDY DESIGN: Over the period from November 1998 to April 2004, 103 children have been fitted with cochlear implants and 11 with auditory brainstem implants in our department, including 65 children aged below 3 years. The present study focuses on 10 children aged less than 12 months fitted with cochlear implants from November 1998 to December 2003. METHODS: The children's ages ranged from 4 to 11 (mean 9.5) months. Five were males and five females. All received a Nucleus CI 24 M. Postoperative auditory performance, as evaluated at the latest follow-up, was based on the category of auditory performance (CAP). The results obtained in these 10 children were compared with those obtained with cochlear implants in children belonging to older age brackets. The criteria used to assess speech performance were onset of babbling onset and babbling spurt, and the results observed were compared with those of a control group of 10 normally hearing children. RESULTS: Surgery was uneventful, and no immediate or delayed complications were encountered. Auditory performance was seen to increase as function of early age of implantation and length of implant use. All 10 children had a CAP score of 3 within 6 months of cochlear implant activation. The onset of babbling occurred very early (i.e., within 1 to 3 months of activation of the implant in all 10 patients), regardless of age at implantation, whereas the babbling spurt was recorded at times ranging from 3 to 5 months after implant activation. The positive impact of early implantation on babbling was clearly shown by the fact that the earlier the activation of the cochlear implant, the closer the results were to the outcomes of normally hearing children. CONCLUSIONS: We encourage very early implantation to facilitate a series of developmental processes occurring in the critical period of initial language acquisition. The indices we used in the present study (i.e., CAP and babbling) suggest that early cochlear implantation tends to yield normalization of audio-phonologic parameters, which enables us to consider the performance of children implanted very early as being similar to that of their normally hearing peers.

Age Factors↗

PubMed2006

Auditory neuropathy in systemic sclerosis: a speech perception and evoked potential study before and after cochlear implantation.

We report the results of speech perception and electrophysiological evaluation of the auditory periphery performed before and after cochlear implantation in a 18-year-old girl with systemic sclerosis (SS) who presented the clinical picture of auditory neuropathy. Transtympanic electrocochleography (ECochG) in response to 0.1 ms clicks was recorded 1 month before cochlear implantation on both sides while the electrically evoked neural response was obtained intraoperatively in the right ear through cochlear implant stimulation. The ECochG recordings revealed the presence of the cochlear microphonic with normal amplitude and threshold on both sides. A compound action potential was only detected in the left ear at high stimulation intensity, while the electrically evoked neural response was clearly identifiable at all the recording sites during neural response telemetry. Standardized speech perception tests were performed 1 month before cochlear implantation and several times after cochlear implant connection. Speech perception scores were close to chance before cochlear implantation while they showed a remarkable improvement thereafter. The results of this study show that subjects affected by SS could present the clinical picture of auditory neuropathy which is possibly underlain by lesions involving the distal portion of auditory nerve fibers and/or synapses with inner hair cells. The restoration of synchronous neural discharge could be achieved by electrical stimulation through cochlear implant.

Adolescent↗

PubMed2006

Prevention of cochlear implant electrode damage.

PURPOSE OF REVIEW: As the current trend in cochlear implantation is to prescribe cochlear implants for patients with residual hearing and to use electroacoustic stimulation, cochlear implant damage must be prevented. This article summarizes current research endeavors to prevent electrode insertion trauma and resulting hearing loss. RECENT FINDINGS: Alteration in surgical technique is necessary with each new electrode design. Nontraumatic surgical technique also requires minimizing acoustic trauma due to drilling the cochleostomy, mechanical damage from electrode insertion, potential infection, and fibrosis of the cochlea. The pattern of hearing loss following electrode insertion trauma is an immediate loss that results from direct trauma to the macroscopic elements of the cochlea and a delayed loss that may reflect the activation of inflammatory and cell death pathways. Therapies under investigation include glucocorticoids, inhibitors of cell death pathways, and hypothermia. SUMMARY: Electrode insertion trauma-induced hearing loss involves multiple mechanisms ranging from mechanical insertion trauma to activation of inflammatory and cell death pathways. The macroscopic mechanical damage to the cochlea may be prevented by improvement of electrode design and surgical technique. The molecular damage needs further studies to assess the efficacy of novel therapeutic strategies in preserving functional residual hearing.

Animals↗

PubMed1997

A European perspective on pediatric cochlear implantation, rehabilitation services, and their educational implications.

OBJECTIVE: To assess the educational implications of pediatric cochlear implantation from the perspective of the implant team. METHODS: Coordinators of pediatric cochlear implant teams throughout Europe took part in a survey using forced-choice questions. Fifty-four centers were originally sent the questionnaire; 41 centers replied. RESULTS: Of 504 children planned to receive cochlear implants in Europe during 1996, 54% (273/504) were aged 2-5 years and 12% (60/504) aged 0-2 years, indicating a trend toward pediatric implantation in younger children. There is a strong commitment to rehabilitation in the teams; 66% (27/41) employ a teacher of the deaf, the ratio of medical/audiological to rehabilitation personnel is 1:2, and 76% (31/41) of the implant teams visit local educators. Of all the children receiving implants to the date of this report, 23% were considered to be in unfavorable educational environments; these were environments where children were taught with an emphasis on sign language and little expectation from audition, and mainstream provision without support from experienced teachers of the deaf. CONCLUSION: There is a high staff input to children with cochlear implants from implant rehabilitation personnel over and above the input received in the educational environment. Hence, it is important for the school and the implant team to mutually agree on their shared responsibilities. Moreover, as the provision of service is variable and inconsistent, the development of guidelines for practice in each country should ensure consistency of rehabilitative and educational support to children with cochlear implants.

Adolescent↗

PubMed1997

Selection criteria for cochlear implants in children.

OBJECTIVE: To determine the selection criteria for cochlear implantation in children. SETTING: Hospital pediatric implant center. PATIENTS AND INTERVENTIONS: Selection of patients depends on medical evaluation, audiometric data, speech discrimination, communication skills, cognitive skills, and psychosocial factors. Patient selection is based on tonal audiometry, computed tomography, magnetic resonance imaging, and electrophysiologic tests. Side of implantation is chosen according to cochlear structure, duration of deafness, and dominant handedness. RESULTS: Ninety-eight cochlear implantations with the Nucleus multichannel implant have been performed at this center since 1990. CONCLUSION: The selection of children for cochlear implantation require close collaboration between the pediatric surgical team, the educational team, and the family.

Auditory Threshold↗

PubMed2000

[The value of basic research as applied to cochlear implants].

This article discusses the value of basic research as applied to cochlear implants. The article is aimed at clinicians and audiologists who are working in the field of cochlear implants or who are interested in this field. The article also gives a more general introduction to modelling for researchers in the clinical environment. It provides an entry point to cochlear implant research and reviews the application of basic research to new developments in cochlear implants. It is shown what has been achieved so far and which problems still exist. The role of multidisciplinary research teams to solve these problems is discussed. Experimental research and modelling co-operate to solve problems and make new discoveries. The importance of modelling as a tool for basic research is emphasized.

Cochlear Implantation↗