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PubMed2002

Cochlear implantation without mastoidectomy: the pericanal electrode insertion technique.

OBJECTIVE: A new minimally invasive cochlear implantation method with direct electrode insertion through the external auditory canal (EAC) is presented. MATERIAL AND METHODS: Surgery begins with a retroauricular skin incision. The bony surface of the mastoid plane behind the ear is dissected free and the skin of the EAC is elevated together with the posterior part of the tympanic membrane. Cochleostomy is performed through the EAC with a microdrill anterior to the round window. A rim is drilled into the postero-superior region of the bony EAC immediately above the incus towards the outer border of the EAC and connected to the retroauricular surface by a short tunnel. The implant device is placed in the usual retroauricular area. The electrode is inserted through the tunnel and rim into the tympanic cavity and pushed into the cochleostomy hole. The electrode is immobilized in the rim using glass ionomer cement and covered with bone dust. After placement of the ground electrode, the retroauricular incision is closed. The tympano-meatal flap is replaced and a dressing is put into the EAC. RESULTS: The new method has been applied thus far in 15 adults and pre-adolescent deaf patients (8 females, 7 males). A MED-EL Combi 40 + device was used in 14 patients and a Nucleus CI24M in 1. Pericanal electrode insertion was easy, with insertion depths into the cochlea of > or = 30 mm with the MED-EL and of 20 mm with the Nucleus device. There were no surgical complications, infections or electrode extrusions during postoperative observation periods ranging from 6 months to > 2 years. The functional results were comparable to those obtained with cochlear implantation via mastoidectomy. The pericanal electrode insertion technique has several advantages, the most important being that the danger of facial nerve damage is minimized and that the operating time is reduced by up to 50%. CONCLUSION: Cochlear implantation with pericanal electrode insertion is a simple, fast and particularly safe option which may replace the classical transmastoidal cochlear implantation method in adults and older children.

Adolescent↗

PubMed2003

The role of mastoidectomy in cochlear implant surgery.

OBJECTIVE: The classical technique for cochlear implantation (CI) involves mastoidectomy and posterior tympanotomy. The question raised in this work is whether mastoidectomy is indispensable in CI surgery. MATERIAL AND METHODS: The advantages and disadvantages of performing mastoidectomy during CI surgery were weighed, in particular the effect of mastoidectomy on chronic secretory otitis media (SOM) and the ability of the electrode to expand in the mastoid during skull growth. RESULTS: No effect of mastoidectomy on chronic SOM was found and the assumption that the electrode in the mastoid cavity has the ability to expand during skull growth was not proven. Eliminating mastoidectomy in CI surgery simplifies the procedure, shortens the duration of surgery, minimizes the amount of drilling and provides broader, better exposure of the middle ear and promontory. Mastoidectomy was found not to be obligatory in CI surgery and in fact may have more disadvantages than advantages. CONCLUSION: The development of alternative CT techniques which eliminate the need for mastoidectomy is justified.

Adolescent↗

PubMed1993

Cochlear implants and otitis media: considerations in two cleft palate patients.

Cochlear implantation is a safe and effective means of rehabilitating profound sensory deafness. The implications of coincident chronic middle ear disease upon the operative procedure and auditory results have received little attention in the literature. We describe two patients, each with congenital cleft lip and palate and secondary chronic otitis media with effusion, who received multichannel cochlear implants following bacterial meningitis. One patient (a three-year-old girl) was implanted in the standard fashion while the other (a 38-year-old-man) underwent middle ear and mastoid obliteration. Our findings suggest that chronic otitis media should not be a deterrent to cochlear implantation.

Adult↗

PubMed2004

The role of spectral and temporal cues in voice gender discrimination by normal-hearing listeners and cochlear implant users.

The present study investigated the relative importance of temporal and spectral cues in voice gender discrimination and vowel recognition by normal-hearing subjects listening to an acoustic simulation of cochlear implant speech processing and by cochlear implant users. In the simulation, the number of speech processing channels ranged from 4 to 32, thereby varying the spectral resolution; the cutoff frequencies of the channels' envelope filters ranged from 20 to 320 Hz, thereby manipulating the available temporal cues. For normal-hearing subjects, results showed that both voice gender discrimination and vowel recognition scores improved as the number of spectral channels was increased. When only 4 spectral channels were available, voice gender discrimination significantly improved as the envelope filter cutoff frequency was increased from 20 to 320 Hz. For all spectral conditions, increasing the amount of temporal information had no significant effect on vowel recognition. Both voice gender discrimination and vowel recognition scores were highly variable among implant users. The performance of cochlear implant listeners was similar to that of normal-hearing subjects listening to comparable speech processing (4-8 spectral channels). The results suggest that both spectral and temporal cues contribute to voice gender discrimination and that temporal cues are especially important for cochlear implant users to identify the voice gender when there is reduced spectral resolution.

Adult↗

PubMed2005

Voice gender identification by cochlear implant users: the role of spectral and temporal resolution.

The present study explored the relative contributions of spectral and temporal information to voice gender identification by cochlear implant users and normal-hearing subjects. Cochlear implant listeners were tested using their everyday speech processors, while normal-hearing subjects were tested under speech processing conditions that simulated various degrees of spectral resolution, temporal resolution, and spectral mismatch. Voice gender identification was tested for two talker sets. In Talker Set 1, the mean fundamental frequency values of the male and female talkers differed by 100 Hz while in Talker Set 2, the mean values differed by 10 Hz. Cochlear implant listeners achieved higher levels of performance with Talker Set 1, while performance was significantly reduced for Talker Set 2. For normal-hearing listeners, performance was significantly affected by the spectral resolution, for both Talker Sets. With matched speech, temporal cues contributed to voice gender identification only for Talker Set 1 while spectral mismatch significantly reduced performance for both Talker Sets. The performance of cochlear implant listeners was similar to that of normal-hearing subjects listening to 4-8 spectral channels. The results suggest that, because of the reduced spectral resolution, cochlear implant patients may attend strongly to periodicity cues to distinguish voice gender.

Adult↗

PubMed2004

Cochlear implantation in an adult patient with auditory neuropathy.

We present a case report of effective cochlear implantation for an adult patient with auditory neuropathy. A 34-year-old man developed bilateral hearing loss at approximately 10 years of age. His speech discrimination score was very severe despite only moderate sensorineural hearing loss. Absence of auditory brainstem responses (ABR) and preservation of distortion product otoacoustic emissions (DPOAE) were confirmed by our audiological examinations. After cochlear implantation, good responses for electrically evoked compound action potential (EAP) and electrically evoked ABR (EABR) were observed. Postoperatively, his audiological performance was significantly improved. We conclude that cochlear implantation can be a valid option for patients with auditory neuropathy.

Adult↗

PubMed2003

Graham Fraser Memorial Lecture 2002. From frogs' legs to pieds-noirs and beyond: some aspects of cochlear implantation.

The 2002 Graham Fraser Memorial Lecture deals first with the French origins of cochlear implantation in Paris in the 1950s and the role of André Djourno and Charles Eyriès. Following this work in Paris Dr William House in Los Angeles continued work on cochlear implants and, subsequently, experimental implant programmes were started in California, Paris, Vienna and Melbourne. The next section of this lecture covers the experimental work of Galvani in establishing the role of electricity in physiology. The results of his first experiments were published in 1791, the year that Mondini produced the first account of a cochlear malformation in a congenitally deaf child. At around the same time sign language for congenitally deaf children was being developed for the first time in Paris by Epée and the first disputes occurred between oralists and those who promoted signing for the education of congenitally deaf children. In a present day cochlear implant programme good results from implanting congenitally deaf children at an early age and implanting adults who have become profoundly deaf are now taken for granted. We do have much to learn, however, from more complex implant candidates and some examples of such candidates are presented. Lastly, looking to the future, the use of PET scanning to try and gain information about how the brain handles the information provided to it by a cochlear implant is described.

Cochlear Implantation↗

PubMed1993

[Cochlear implant in children. General principles. Results of the Lyons team].

Cochlear implant is a transductor system used to transform acoustic vibrations into an electric current which stimulates the vestibulocochlear nerve. It may be either extracochlear, the nerve being stimulated through an electrode placed near the cochlea, or intracochlear, the electrode being inserted within the cochlea. Cochlear implantation in children is nowadays a safe and performing method to complete total deafness of sensorineural origin. However it must be only applied to total deafness which fail to show an improvement with conventional acoustic prostheses. In addition, partly for anatomical reasons, partly because of the time required to be sure of the indication, cochlear implantation can only be performed between 18 and 24 months of age.

Child↗

PubMed2004

Revision cochlear implant surgery in adult patients with suspected device malfunction.

OBJECTIVE: To report the outcomes of patients that have undergone revision cochlear implant surgery for suspected device malfunction. STUDY DESIGN: Retrospective case series. SETTING: Academic medical center. PATIENTS: Adult cochlear implant patients with devices that fail to lock or maintain a lock but are associated with troubling signs and symptoms. INTERVENTION: Revision cochlear implant surgery. MAIN OUTCOME MEASURES: Demographics, presenting signs and symptoms, surgical findings, complications, audiologic performance and device analysis. RESULTS: To date, 33 revision cochlear implant operations have been performed in 30 patients. Eight (24%) presented with a failure of the speech processor to lock with the internal device (i.e., hard failure). Twenty-five (76%) presented with either aversive auditory (n = 23 [92%]) or nonauditory (n = 21 [84%]) symptoms or performance-related issues (n = 16 [64%]) while maintaining a lock (i.e., suspected soft failure). Revision surgery resulted in resolution of the patient's presenting signs and symptoms in nearly 90% of cases and significant improvements in auditory performance. Perioperative complications were uncommon. Preoperative testing and device analysis frequently did not reveal the reason for presumed device malfunction. CONCLUSION: Revision cochlear implantation should be considered in patients significantly affected by intolerable auditory and/or nonauditory symptoms or when performance issues have been documented.

Analysis of Variance↗

PubMed2005

Cochlear implantation in severe traumatic brain-injury and paranoid schizophrenia: two case studies.

In view of the demanding instruction and training requirements associated with cochlear implantation;,patients with cognitive impairments have typically been considered to be poor candidates for this procedure. This presumption persists in part because experience and research in this area are limited. We describe our experience with implanting cochlear devices in 2 patients who had significant psychological impairments; 1 patient had experienced a severe brain injury, and the other had paranoid schizophrenia. Nevertheless, both patients were able to follow the implant training program, and they experienced different degrees of improvement in their hearing. We discuss our preoperative evaluations of these patients and the key factors that led to our decision to proceed with surgery.

Adult↗

PubMed2005

The cognition and behaviour of children with cochlear implants, children with hearing aids and their hearing peers: a comparison.

Hearing impairment has been associated with cognitive deficits. It is not yet clear whether cochlear implants enable children to reduce or overcome these deficits. This study examined whether hearing impaired children with cochlear implants differed from hearing impaired children without cochlear implants or from hearing children. The three age-matched groups were compared on a non-verbal measure of cognition, the Leiter International Performance Scale-Revised (LIPS-R), and a measure of behaviour, the Child Behaviour Checklist (CBCL). Apart from their scores on the Attention Sustained Subtest of the LIPS-R, the performance of the implanted group and the hearing group closely corresponded, while the hearing impaired children without cochlear implants performed below the level achieved by both these groups. There were no differences between any groups on the CBCL. It was concluded that hearing impaired children with cochlear implants were able to perform at the same non-verbal cognitive level as hearing children.

Analysis of Variance↗

PubMed1997

Cost analysis of cochlear implants in deaf children in The Netherlands.

OBJECTIVE: The purpose of the study was to determine the costs of cochlear implants in children regarding the phases of selection, implantation, rehabilitation, and aftercare. STUDY DESIGN: This study was a prospective cost analysis paralleling a noncomparative observational study. SETTING: This study was conducted at a university hospital to evaluate cost data on selection and implantation and at an institute for the deaf to evaluate cost data on rehabilitation and aftercare. PATIENTS: The study group consisted of prelingual deaf children (mean age, 7 years; range, 4-11 years). INTERVENTION: A total of 106 deaf children were screened, of whom 20 received a cochlear implant. MAIN OUTCOME MEASURES: This study concentrated on the cost of cochlear implants. Volumes of utilization of human resources and materials were registered during the 1-year follow-up. For the subsequent period, volumes were modeled on planned aftercare activities. RESULTS: Real total medical costs per implanted child were $63,922; selection phase, $7,747; implantation phase, $30,442; rehabilitation phase, $13,428; and aftercare, $12,305. Nonmedical costs were $1,839. Calculations were based on 1994 prices, and a time horizon of 5 years was used. The economic consequences of cochlear implants on educational needs were not taken into account because of the limited follow-up period. A sensitivity analysis of the rate of implanted children as part of the number of screened children showed a moderate impact on the total cost. CONCLUSIONS: Compared to the results of cost analysis in other countries, the costs of the pediatric cochlear implants program in The Netherlands are relatively high. Most discrepancies can be explained by methodologic differences in the cost analyses.

Child↗

PubMedDate not supplied

A multiple-electrode cochlear implant.

A multiple-electrode cochlear implant comprised of three intracochlear and four extracochlear electrodes is described. A percutaneous plug allowed for direct electrical measurements and presentation of stimuli to selected electrode combinations. Electrical impedance measurements revealed functions that decreased as frequency increase to about 20 kHz. Absolute impedance magnitude varied across electrodes. Equal loudness contours were similar in shape for all three cochlear electrodes, although dynamic range was significantly reduced for the most apical electrode. Periodicity and place pitch were demonstrated; effects were most salient for low frequency stimuli. A 3-channel sound processor was built and multiple-channel stimulation was compared to single-channel stimulation. Significant performance differences were not found between single-channel and multiple-channel systems for environmental or speech sounds. However, the patient subjectively reported superior quality with the multiple-channel system.

Auditory Fatigue↗

PubMed2005

Benefit of wearing a hearing aid on the unimplanted ear in adult users of a cochlear implant.

The purpose of this investigation was to document performance of participants wearing a cochlear implant and hearing aid in opposite ears on speech-perception and localization tests. Twelve individuals who wore a cochlear implant and a hearing aid on contralateral ears were tested on their abilities to understand words in quiet and sentences in noise, and to localize everyday sounds. All speech stimuli were presented from the front, with the noise stimuli presented from the front, the right, or the left at a 90 degrees angle. Binaural summation in quiet and in noise, binaural squelch effects, and localization were studied to determine bilateral advantages. The magnitude of the monaural head shadow effect (the difference in unilateral performance when noise was facing the unilateral device vs. when the noise was opposite the unilateral device) also was studied. The test setup for localization was composed of an 8-speaker array spanning an arc of approximately 108 degrees in front of each participant. Group results yielded a statistically significant combined benefit of wearing a hearing aid in conjunction with a cochlear implant on opposite ears in noise conditions. Those participants who received a binaural advantage in 1 condition did not necessarily show a binaural advantage in another. Only 2 participants out of 12 were able to localize when wearing 2 devices. Further efforts are required to improve the integration of information from combined use of cochlear implant and hearing aid devices for enhancement of speech perception in noise and localization.

Aged↗

PubMed2004

Audiological performance after cochlear implantation in children with inner ear malformations.

OBJECTIVES: To prove that cochlear implantation is a beneficial method of rehabilitation in deaf children with malformations of the inner ear. DESIGN: The evaluation of auditory responses to speech (EARS) test battery was performed on the children in this study after an average implant use of 3 years. RESULTS: Individual results of six children with inner ear anomalies receiving cochlear implants are presented in this study. Three of the patients showed an incomplete partition (Mondini dysplasia), one had a cochlear hypoplasia and two suffered from an intraoperative cerebrospinal fluid leak. The majority of the children in this study are successful implant users. Wherever possible, test scores are included and subjective case reports given. CONCLUSIONS: Results are similar to those in children with normal cochleas, therefore inner ear malformations found in as many as 20% of patients with congenital sensorineural hearing loss are no contraindication for cochlear implantation. Nevertheless, factors influencing the success of implantation are multiple, including a thorough preoperative radiological examination, a well-performed surgery and an individually tailored postoperative rehabilitation programme.

Audiometry, Speech↗

PubMed2003

Intensity discrimination and increment detection in cochlear-implant users.

Intensity difference limens (DLs) were measured in users of the Nucleus 22 and Clarion v1.2 cochlear implants and in normal-hearing listeners to better understand mechanisms of intensity discrimination in electric and acoustic hearing and to evaluate the possible role of neural adaptation. Intensity DLs were measured for three modes of presentation: gated (intensity increments gated synchronously with the pedestal), fringe (intensity increments delayed 250 or 650 ms relative to the onset of the pedestal), and continuous (intensity increments occur in the presence of a pedestal that is played throughout the experimental run). Stimuli for cochlear-implant listeners were trains of biphasic pulses; stimuli for normal-hearing listeners were a 1-kHz tone and a wideband noise. Clarion cochlear-implant listeners showed level-dependent effects of presentation mode. At low pedestal levels, gated thresholds were generally similar to thresholds obtained in the fringe and continuous conditions. At higher pedestal levels, however, the fringe and continuous conditions produced smaller intensity DLs than the gated condition, similar to the gated-continuous difference in intensity DLs observed in acoustic hearing. Nucleus cochlear-implant listeners did not show consistent threshold differences for the gated and fringe conditions, and were not tested in the continuous condition. It is not clear why a difference between gated and fringe thresholds occurred for the Clarion but not the Nucleus subjects. Normal-hearing listeners showed improved thresholds for the continuous condition relative to the gated condition, but the effect was larger for the 1-kHz tonal carrier than for the noise carrier. Findings suggest that adaptation occurring central to the inner hair cell synapse mediates the gated-continuous difference observed in Clarion cochlear-implant listeners and may also contribute to the gated-continuous difference in acoustic hearing.

Acoustic Stimulation↗

PubMed2006

Spectral and temporal cues in cochlear implant speech perception.

OBJECTIVE: Taking advantage of the flexibility in the number of stimulating electrodes and the stimulation rate in a modern cochlear implant, the present study evaluated relative contributions of spectral and temporal cues to cochlear implant speech perception. DESIGN: Four experiments were conducted by using a Research Interface Box in five MED-EL COMBI 40+ cochlear implant users. Experiment 1 varied the number of electrodes from four to twelve or the maximal number of available active electrodes while keeping a constant stimulation rate at 1000 Hz per electrode. Experiment 2 varied the stimulation rate from 1000 to 4000 Hz per electrode on four pairs of fixed electrodes. Experiment 3 covaried the number of stimulating electrodes and the stimulation rate to study the trade-off between spectral and temporal cues. Experiment 4 studied the effects of envelope extraction on speech perception and listening preference, including half-wave rectification, full-wave rectification, and the Hilbert transform. Vowels, consonants, and HINT sentences in quiet, as well as with a competing female voice served as test materials. RESULTS: Experiment 1 found significant improvement in all speech tests with a higher number of stimulating electrodes. Experiment 2 found a significant advantage of the high stimulation rate only on consonant recognition and sentence recognition in noise. Experiment 3 found an almost linear trade-off between the number of stimulation electrodes and the stimulation rate for consonant and sentence recognition in quiet, but not for vowel and sentence recognition in noise. Experiment 4 found significantly better performance with the Hilbert transform and the full-wave rectification than the half-wave rectification. In addition, envelope extraction with the Hilbert transform produced the highest rating on subjective judgment of sound quality. CONCLUSIONS: Consistent with previous studies, the present result from the five MED-EL subjects showed that (1) the temporal envelope cues from a limited number of channels are sufficient to support high levels of phoneme and sentence recognition in quiet but not for speech recognition in a competing voice, (2) consonant recognition relies more on temporal cues while vowel recognition relies more on spectral cues, (3) spectral and temporal cues can be traded to some degree to produce similar performance in cochlear implant speech recognition, and (4) the Hilbert envelope improves both speech intelligibility and quality in cochlear implants.

Adult↗

PubMed2006

[Paediatric cochlear implantation in the first year of life: preliminary results].

BACKGROUND: The success of cochlear implants in children was followed by a stepwise reduction in age at time of surgery. As a result of newborn hearing-screening (NHS) and the reliable audiologic diagnostic procedure, the question is raised as to whether an implantation before the age of 1 year is effective and safe in terms of surgery and rehabilitation. METHOD AND PATIENTS: This retrospective study included 27 children implanted before the age of 1 year (Gr. 1) and 89 children implanted between the age of 1 and 2 years (Gr. 2). Patient related data were analysed for individual history, surgery, rehabilitation and speech understanding. RESULTS: The incidence of complications was not increased in Gr. 1. The fitting of a speech processor was effective and uneventful in all children. The development of hearing and speech understanding showed better results after 2 years in Gr. 1. This development is more obvious for absolute age and not to rehabilitation time. CONCLUSION: In order to achieve an optimal timing for the development of speech understanding, cochlear implantation should be performed before the age of 2 years. This study revealed no additional risks for children in Gr. 1, but the development of speech understanding was better. As a consequence, cochlear implantation should be considered for very young children with an identified bilateral profound hearing loss.

Cochlear Implantation↗