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22 channel cochlear implants were implanted in 3 postlinguistical deafened adults and a prelinguistical deafened adolescent. All 4 patients including one with total cochlear ossification and another with congenital cochlear malformation showed significant auditory performance and demonstrated satisfactorily improved speech perception test scores postoperatively.
BACKGROUND: The cochlear implant is the therapy of choice for completely deaf patients. With this concept speech communication can be restored or developed. METHODS: The selection of the implant system may depend on different factors. As long as speech competence is thought to be of highest importance, a fast stimulation strategy involving a state of the art cochlear implant that provides 1500 Hz for every single electrode is close to the optimum. Further parameters include deep insertion into the cochlea (normally 30 mm) and other technical details. RESULTS: With these conditions fulfilled, about 2/3 of the adult deaf patients will later be able to use a telephone. Children who received implants in due time and do not have other cerebral defects will be partly able to meet with the requirements of normal schools.
CONTEXT: Unilateral cochlear implantation is a cost-effective intervention for profound bilateral hearing loss. There is worldwide interest in providing implants bilaterally. OBJECTIVE: To use modeling to estimate the cost of gaining a quality-adjusted life-year by providing implants to both ears of profoundly postlingually deafened adults. DESIGN: Economic scenario analysis relating the costs of providing implants to estimates of the gain in health-related quality of life (utility) from unilateral and bilateral implantation. SETTING: Fourteen hospitals in the United Kingdom National Health Service and 1 Medical Research Council research unit. PARTICIPANTS: Normal-hearing adult volunteers with knowledge of implantation (n = 70). Adults undergoing unilateral implantation who either did not benefit from acoustic hearing aids preoperatively (type 1, n = 87) or benefited marginally (type 2, n = 115). MAIN OUTCOME MEASURES: Changes in utility from unilateral and bilateral implantation estimated with the time trade-off technique (volunteers) and from unilateral implantation measured with the Mark II Health Utilities Index (patients); costs of providing implants and sustaining patients who have undergone implantation (health care perspective). RESULTS: Gains in utility from unilateral implantation estimated by volunteers did not differ significantly from gains recorded by patients, giving credibility to the volunteers' estimate of the gain from bilateral compared with unilateral implantation. Cost-utility ratios, in pounds sterling per quality-adjusted life-year, based on volunteers' estimates, were pound 16,774 (type 1: unilateral implantation vs no intervention), pound 27,401 (type 2: unilateral implantation vs management with hearing aids), pound 61,734 (simultaneous bilateral implantation vs unilateral implantation), and pound 68,916 (provision of an additional implant vs no additional intervention). CONCLUSION: More quality of life is likely to be gained per unit of expenditure on unilateral implantation than bilateral implantation.
BACKGROUND: Cochlear implantation is a widely used means of treating deafness and severe hearing disorders. The surgical procedure includes inserting the cochlear implant electrode array into the cochlea and embedding the corresponding signal receiver in the mastoid bone behind the ear. Postoperative fitting of the externally worn speech processor is very important for successful use of the cochlear implant. For this purpose, electrically elicited stapedius reflex threshold values can be used. However, stapedius reflex threshold values measured intraoperatively are influenced by anaesthetics. The goal of this retrospective study was to find out whether electroencephalogram (EEG) control of anaesthesia produces more reliable reflex threshold values as a basis for the fitting of the speech processor. METHODS: Three groups of children, after surgery for cochlear implantation, were analysed with regard to the magnitude of intraoperative electrically elicited stapedius reflex threshold values and their deviations from postoperatively determined maximum comfortable levels (group 1: methohexital/remifentanil with EEG monitoring, n = 10; group 2: isoflurane/fentanyl with EEG monitoring, n = 9; group 3: isoflurane/fentanyl without EEG monitoring, n = 11). RESULTS: Children with EEG monitoring had significantly lower electrically elicited stapedius reflex threshold values and also significantly lower differences between intraoperative stapedius reflex threshold values and postoperatively determined maximum comfortable levels. CONCLUSIONS: Electroencephalogram monitoring in cochlear implantation is of considerable value in controlling anaesthesia and improving speech processor fitting based on more reliable intraoperative neurophysiological data.
BACKGROUND: Cochlear implantation is nowadays a reliable and well-accepted method of auditory rehabilitation in selected adults and children. METHODS: We present rehabilitation data on 21 adult patients provided with the Nucleus CI22 M cochlear implant using the SPEAK strategy. RESULTS: Results of first tune-up show an open set speech understanding in approximately 50% of patients. Long-term results also reveal further improvement in patients who had no open set speech understanding. Our data seem to indicate similar results in comparison to other groups using the CIS strategy. CONCLUSIONS: In adults, open set speech understanding can be achieved even at the first tune-up. Results of early rehabilitation seem to be influenced by duration and etiology of deafness, experience with hearing aids, and other factors.
Cochlear Implantation is a recognized procedure for acoustical rehabilitation of the profoundly or totally deaf unable to effectively use a traditional hearing aid. Since 1989, 30 patients (27 postlingual and 3 perilingual) have been operated on by the senior Author with the implantation of a multichannel device: Med-El (3 cases), Clarion (3 case) and Nucleus Mini-22 (24 cases). The first 24 Nucleus cases, with a multipeak speechcoding strategy, are the object of this retrospective report. Selection of patients was performed according to an international protocol which includes PTA and Speech Audiometry, CT and/or MRI imaging of the ear, the Promontorial Test, an evaluation of lip reading ability, a psychological evaluation, a trial with two recent and currently available aids. The operation was carried out under general anesthesia. An extended endaural approach was adopted. The internal package of the device was firmly seated onto the temporalis squama and the electrode array was introduced into the tympanic cleft via a posterior tympanotomy. The electrode system was inserted into the scala tympani through a cochleotomy drilled out at the anteroinferior border of the round window. The whole system was fixed to the bony walls of the mastoid and squama using an ionomeric bone bonding agent. Starting at the second postoperative month and up to the 24th month of utilization of the device, each patient was evaluated with regard to his or her ability to recognize environmental sounds, to detect prosody transitions and to understand speech with and without visual cues. Selected tests, either close or open set, were used from the MAC and the Iowa Cochlear Implant Battery, as well as the Helen test. Telephone conversation was also evaluated. Results were very encouraging in all cases, showing that the multichannel cochlear device provides the properly selected patient a substantial auditory rehabilitation allowing him or her to understand speech in most instances without any visual cue.
Cochlear implants have become a standard treatment modality for sensorineural hearing loss. In this review article, assembly and function of a cochlear implant are described. Cochlear implants replace the normal inner ear by transforming acoustic sound signals into electric stimuli and deliver these to the auditory nerve. Speech processors translate the acoustic signal of the microphone into one that fits electrostimulation of the auditory system. In multiple steps, the signal has to be analyzed and processed to fit the demands of electrical stimulation. The speech processor then sends commands and the energy for stimulation to the implanted parts via a transcutaneous high frequency radio link. The implant refers the information as electrical stimuli to each electrode contact.
The Clarion cochlear implant was developed in the USA and received FDA approval in August 1996. It consists of an implantable cochlear stimulator (ICS), speech processor with headpiece, and in addition, a clinician's programming system and portable cochlear implant tester. One of the features of the device is its stimulation-coding process for which two methods of continuous interleaved sampling (CIS) and compressed analogue (CA) are applicable. Regardless of which is used, stimulation can be provided over 8 channels. The device was used in 2 cases. Both patients were operated on in October 1996, and 16 electrodes in 8 pairs were mounted in the cochlea. Mapping, performed 3 weeks after the operation, showed good speech perception in both patients with only a cochlear implant in the "open-set" status. CIS was used as the stimulation-coding method. CA has yet to be applied.
BACKGROUND: Cochlear implant surgery is a well standardized therapy for rehabilitation of congenital or acquired deafness at all ages. Mastoidectomy, posterior tympanotomy, cochleostomy and electrode insertion are performed consistently worldwide. Recently newly developed types of incision are taken into account. In our experience over more than 15 years the extended endaural incision has proven to be reliable with a low complication rate. OBJECTIVE: To evaluate a modified retroauricular incision for clinical use and complication rate in cochlear implant surgery with devices of different manufacturers. MATERIAL AND METHODS: We performed a prospective analysis of cochlear implant surgeries between 03/2003 and 03/2004. In all cases a modified retroauricular incision was used. Necessary adaptations of incision, depending on the device used, and postoperative complications were evaluated. RESULTS: In 76 ears a retroauricular incision was performed. Depending on the shape and size of receiver/stimulator an extension of the incision was necessary. The mean observation time was 6.3 months. Intra- or postoperative complications were not observed. In one case a skin dehiscence following trauma 28 days after surgery was reported without dehiscence of fascia or implant failure with uneventful healing after secondary suture. CONCLUSIONS: With regard to the results with the extended endaural incision the modified retroauricular incision allows a safe access for cochlear implant surgery. Observation of long term results and outcomes in revision surgery is mandatory.
OBJECTIVES: To assess a group of consecutively implanted children over 10 years after implantation with regard to implant device use and function, speech perception, and speech intelligibility outcomes; and to document current academic or occupational status. STUDY DESIGN: A prospective longitudinal study assessing device function, device use, speech perception, speech intelligibility, and academic/occupational status of implanted deaf children. SETTING: Pediatric tertiary referral center for cochlear implantation. METHODS: The auditory performance and speech intelligibility development of 30 profoundly deaf children were rated before cochlear implantation and at 5 and 10 years after implantation using the Categories of Auditory Performance and the Speech Intelligibility Rating. The academic and/or occupational status of the participants after 10 years of implant experience was documented. All children received a Nucleus multichannel cochlear implant between the ages of 2.5 and 11 years (mean age at implantation, 5.2 yr). Implant experience ranged from 10 to 14 years of use. RESULTS: After 10 years of implant experience, 26 subjects (87%) reported that they always wore their device; 2 subjects (7%), frequently; and 1 subject (3%), occasionally. Only one child had discontinued use of his device. After 10 years of implant use, 26 (87%) of the children understood a conversation without lip reading and 18 (60%) used the telephone with a familiar speaker. Ten years after implantation, 23 (77%) of the subjects used speech intelligible to an average listener or a listener with little experience of a deaf person's speech. One-third to one-half of the implanted children continued to demonstrate improvements at 5 to 10 years of implant use. Of the 30 implanted children, 8 (26.7%) experienced nine device failures. The length of time from identification of the first faulty electrode to reimplant surgery ranged from 2 weeks to 5.5 years, as several failures were gradual or intermittent. However, all children were successfully reimplanted. At the end of the study (10-14 yr after implantation), 19 subjects were in secondary school for children aged 11 to 16 years: 6 were in mainstream schools, 7 were in specialist hearing-impaired units attached to a mainstream secondary school, and 6 were in schools for the deaf. Of the remaining 11 subjects, 4 were in college studying vocational subjects, 2 were in a university studying for a bachelor's degree, 3 were working full-time, 1 was working and going to a university part-time, and 1 was a full-time mother of two young children. CONCLUSION: All but 1 of the 30 implanted children continue using their devices 10 to 14 years after implantation, showing significant progress in speech perception and production. Device failure was frequent, but successful reimplantation occurred in all cases. One-third to one-half of the implanted children in this study continued to demonstrate improvements at 5 to 10 years of implant use. All children are studying or working and are actively involved in their local communities. The results suggest that cochlear implantation provides long-term communication benefit to profoundly deaf children that does not plateau for some subjects even after reimplantation. This study further indicates that cochlear implant centers need the structure and funding to provide long-term support, counseling, audiologic follow-up, rehabilitation, and device monitoring to implanted children.
This paper reports initial results for the CLARION Multi-Strategy Cochlear Implant, presently under investigational study in Europe. A magnetless implantable cochlear stimulator (ICS) with an ear-mold-supported headpiece was designed in response to an increasing demand for a magnetic resonance imaging (MRI)-compatible cochlear implant. Surgical technique, accompanying magnetless headpiece, and MRI compatibility were evaluated in 11 deaf patients (ages 6 to 62 years) who were implanted with a magnetless Clarion implant. Because of the headset mechanics, the ICS was implanted closer behind the ear than a magnet-containing ICS. The ICS-MRI compatibility was investigated with 1.5- and 0.3-T MRI. Results showed that the surgery was relatively safe and easy to learn. The headset was stable and reliable. The MRI compatibility tests indicate that the ICS poses no contraindication for patients needing MRI. Overall, the results suggest that the Clarion magnetless cochlear implant is relatively safe and easy to implant, is MRI-compatible, and functions well with the ear-mold-supported headpiece.
BACKGROUND: Historically, vertigo after cochlear implantation has not been frequently documented. This differs from the authors' experience in reviewing all adults who underwent implantation at their center from 1995 through 1999. OBJECTIVE: To determine the incidence of vertigo after cochlear implantation and to describe appropriate intervention. STUDY DESIGN: A retrospective case review. PATIENTS: All adults receiving cochlear implants at the Atlanta Cochlear Implant Group from 1995 through 1999. INTERVENTION AND OUTCOME MEASURE: Vertigo was identified through subjective reports, provoked nystagmus, and static force plate evaluation. Vestibular therapy was initiated for each vertiginous patient after cochlear implant surgery. The outcome of treatment was resolution of vertigo and return to functional status. RESULTS: Approximately three-quarters of the adults with implants experienced vertigo or imbalance. Vestibular therapy was beneficial in alleviating these symptoms. CONCLUSION: A significant number of patients experienced vertigo after cochlear implant surgery. Vestibular therapy is a successful treatment of condition.
Multielectrode cochlear implants rely on differential stimulation of the cochlear nerve for presenting the brain with the spectral and timing information required to understand speech. In implant patients, the degree of overlap among cochlear nerve fibers stimulated by the different electrodes constitutes the electrode interaction. Electrode interaction degrades the spectral resolution of the implant's stimulus. We sought to define electrode interaction in a cohort of pediatric cochlear implant subjects as a function of both stimulus intensity and electrode location along the array. The 27 pediatric subjects that completed the study were implanted with either the Clarion Hi-Focus array with or without positioner, the Nucleus 24 Contour array, or the Nucleus 24 Straight array. All but two of the patients had congenital hearing loss, and none of the patients had meningitis prior to the onset of deafness. The cochlear nerve response was measured with the electrically evoked compound action potential (ECAP). A forward masking protocol was used such that a probe stimulus electrode remained fixed while a preceding masker was moved across the array. Electrode interaction was estimated by measuring the unmasked probe response minus the masked probe response. Three probe locations and three probe intensities were examined for each subject. At all probe locations, electrode interaction increased as probe intensity increased (p < 0.05). Interaction at the basal probe was less than that at either the middle or apical probe locations (p < 0.05), and significant correlation found between probe distance from the basal end of the array and electrode interaction (p < 0.001). These results demonstrate that in this cohort of pediatric subjects, electrode interaction depended on both stimulus intensity and probe location. Implications of these findings on future implant array design and current implant fitting strategies are discussed. The impact of electrode interaction on implant performance is yet to be elucidated.
Cochlear implantation by facial recess is nowadays the approach of choice in normal anatomical conditions in the middle and inner ear. When deafness is coincident with chronic otitis media or partial obliteration of the cochlea, others approaches can be applied. Authors presented lateral petrosectomy as an approach for cochlear implantation in two cases. In both patients all the electrodes were inserted. There were any complications in postoperative period. Lateral petrosectomy is nowadays well codified technique. It is possible to apply this approach for cochlear implantation in cases with chronic otitis media. Good access to the cochlea especially to its basal turn allows for good insertion even in partial obliteration of the scala tympani.
OBJECTIVE: In patients with total or surgically inaccessible cochlear obliteration, only a reduced number of active electrodes can be inserted with standard cochlear implants, resulting in below average auditory performance. Therefore, a special implant with two electrode arrays was developed on the basis of the Nucleus 22 cochlear implant, the socalled Double Array. One electrode array with 11 active electrodes is inserted into the basal turn of the cochlea, while the second array with 10 active electrodes is inserted into the second turn. The Double Array is now available on the basis of the more advanced Nucleus 24 with 11 active electrodes on each array and two reference electrodes, one at the case and the second one an additional ball electrode, which is placed under the temporalis muscle. For device description and surgical technique see Lenarz et al. (2001). This paper presents psychophysical data on pitch discrimination and auditory performance of patients implanted with a Double Array on the basis of the Nucleus 22. STUDY DESIGN: A prospective intra-individual study using a Latin square paradigm was performed in six adult patients with obliterated cochlea who received the Nucleus 22 Double Array. After appropriate fitting and loudness balancing, patients were tested either with the basal, the apical or both electrode arrays. Apart from auditory performance tests including numbers and monosyllable word tests, pitch discrimination was determined with a defined procedure. RESULTS: When activating each array alone, auditory performance was better with the basal array than with the apical array. Both arrays together showed marked improvement compared with the basal array, indicating an additional effect of the second array. Pitch discrimination was significantly better for the electrodes in the basal turn than in the second turn, indicating differences in electrical excitation of the auditory nerve fibers. Pitch discrimination was positively correlated with auditory performance data. CONCLUSION: The additional apical array leads to significant improvement in auditory performance in patients with obliterated cochleae by increasing the number of intracochlear electrodes. Despite reduced pitch discrimination, the apical array provides important information for speech recognition. For this reason the Double Array provides a profound advantage for patients with obliterated or surgically inaccessible cochleae.
The adult cochlear implant programme in Manchester was established in 1988, initially using funding obtained from the HEAR (Help Ear and Allied Research: charity number: 519784) charity before government resources became available in the mid-1990s. Manchester was the first centre in the UK to implant multichannel devices on a regular basis. To date, over 250 adults have been implanted, including nine bilateral and eight deaf-blind patients. All the patients have a postlingual onset of severe-profound hearing loss; 73% (n = 175) of the implants performed used a Nucleus multichannel implant and 24% (n = 58) used a Medel multichannel implant. In addition, the team has implanted three Medel single channel devices, two Ineraid devices and one Clarion High Focus II device. This study is a retrospective analysis of the trends and outcomes in implant fitting during the first 14 years (1988-2002) of the programme. The paper describes the patient demographics and audiological complications for 240 implantations performed on 214 patients. Speech perception outcomes are reported for a subset of the patients. The average score for the Bench, Kowal, Bamford sentence test at the post-18-month stage of implant use is 66% and for Arthur Boothroyd words 53%. Trends in the series are analysed with respect to the change in criteria for adult implantation, the move towards bilateral implantation and the rate of uptake of cochlear implants by different ethnic groups.
Most pediatric cochlear implant programs support a team approach for post-implant services. However, individuals directly involved in the care of these children often have differing opinions on the child's performance. We describe our experience with four children, aged 3 to 10 at the time of implantation, who have used the Nucleus 22-channel cochlear implant device for at least nine months. A questionnaire, focusing on the individual's observations of the child's speech and hearing performance in their particular setting (i.e., clinic, home, school), was completed by the child's parent(s), therapist and classroom teacher. Overall, performance in structured settings (i.e., testing and therapy sessions) was not in agreement with performance in unstructured settings (i.e., classroom and home environments). The results suggest that different individuals interacting with the same child in different environments often have differing perceptions of the child's performance. Based on the information obtained on the four cases, we discuss factors to consider in assessing the real-life performance of pediatric cochlear implant recipients.
The Center of Cochlear Implantation at St-Petersburg ENT Research Institute was set up in 1997. For three years of its activity 19 cochlear implantations were made in patients of different age. All of them received Combi 40/40+ implants (Med-El, Austria). Prospects of cochlear implantation and problems of its introduction in Russia are analysed.