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PubMed2003

External auditory canal closure in cochlear implant surgery.

OBJECTIVE: To evaluate surgical techniques and complications associated with external auditory canal (EAC) closure in cochlear implant surgery. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center with a large cochlear implant program. PATIENTS: Twenty-eight patients (8 adults and 20 children) underwent multichannel cochlear implantation with EAC closure. The follow-up periods ranged between 1 and 10 years. Closure of the EAC was performed in conjunction with implantation of ears with chronic suppurative otitis media or cochlear drill-out procedures for ossification, or for access to the cochlea in patients with abnormal temporal bone anatomy. A modified Rambo technique was used for EAC closure in all but one case. INTERVENTIONS: Cochlear implantation with EAC closure and subsequent clinical and radiologic follow-up. MAIN OUTCOME MEASURES: Postoperative complications or the development of cholesteatoma in the implanted ear. RESULTS: Cholesteatoma developed in the implanted ear in two patients. Breakdown of EAC closure occurred in one of these patients. The details of these patients are reviewed. CONCLUSION: Closure of EAC can be done with relatively low risk. Close and careful follow-up is required for early detection of a developing cholesteatoma.

Adolescent↗

PubMed2004

Innovation and funding specialist services. Cochlear implantation.

This paper traces the innovative development of the Nottingham Cochlear Implant Programmes. The paediatric programme was the first to be established in the UK in 1989 and remains the largest programme in the UK today, whilst the adult programme developed later, in 1994. The first section of the paper describes trends in service development whilst the second section makes detailed reference to the history of funding arrangements which enabled the programme to become established. The third part of the paper examines the (de)merits of locality purchasing versus centralised purchasing for specialist services, using cochlear implantation as way of illustration. The paper aims to provide an informative history of the development of the service in Nottingham and from this background create debate as to the most appropriate future funding mechanism for cochlear implantation in particular and specialist services in general.

Adult↗

PubMed2004

[The cochlear implant. Molecular arguments favouring early implantation].

BACKGROUND: An important factor in the clinical outcome of cochlear implantation is the age of the patient. Compared to older patients, children with congenital deafness have a better outcome when the implantation is made before the age of 2 years. The cause may lie in the molecular biology of the brain, which changes during postnatal maturation. METHODS: Protein probes were obtained from tissue of the rat inferior colliculus at different ages. The probes were analyzed using 2-dimensional SDS electrophoresis. RESULTS: The expression of GAP-43, a protein expressed by neurons during axonal outgrowth and synaptogenesis, and the total number of the protein species showed a significant reduction during ontogenesis. This shows that while neurons gradually assume their specific function, they downregulate GAP-43 and the molecular complexity decreases. CONCLUSIONS: Due to a lack of neuronal pluripotency at later developmental stages, the flexibility to adapt to the afferent activation provided by a cochlear implant is increasingly limited.

Aging↗

PubMed2000

[The discrimination rate in the consonant by cochlear implanted].

OBJECTIVE: To evaluate the effect of the discrimination rate in the consonant by cochlear implanted. METHOD: The four cases by cochlear implanted have rehabilitated with hearing speech for 1.0-1.5 years. RESULT: The discrimination rate in the four cases by cochlear implanted was 76.0% in the consonant, 94.1% in the vowel. CONCLUSION: The discrimination rate in common language of Chinese was lower than that of vowel. When the patients discriminated the consonants with the same formants feature, the chance of the auditory is relatively high.

Adult↗

PubMed1995

[Resorbable intracutaneous suture as wound closure in cochlear implant].

The extended incision in cochlear implantation has to be performed for several reasons; therefore the wound closure needs single or continuous suture for the skin. The suture removal seems to be traumatic for children. That is why we have using an intracutaneous absorbable suture to avoid material removal for more than 6 months now without any complications in the 35 patients in question.

Child↗

PubMed1992

[Results of cochlear implants in totally deaf subjects].

Cochlear implants have been applied on a limited scale in the Netherlands since 1985. In a government sponsored health service trial the method was further explored from 1988 to 1991. During this period 20 persons were implanted, ten with a Vienna extracochlear system and ten with a 22-electrode Nucleus intracochlear system. The ages varied from 5 to 62, the duration of deafness from 2 to 47 years. Some patients were congenitally deaf. The major cause of deafness was meningitis. The effect of the implantation was tested with the 'minimal auditory capability' test battery adapted for the Dutch language. 18 persons were wearing their system for more than 8 h a day; one person, a prelingually deaf did no longer use his implant while another one only used it occasionally. Except for two persons, all scored above chance level on several tests. The postlingually deaf persons with the Nucleus system all achieved a certain degree of open set speech understanding without lipreading. With the aim of achieving better selection criteria a new trial has started with the same financial sources in cooperation with the Utrecht University Hospital.

Adolescent↗

PubMed2003

Evaluation of the high-resolution speech coding strategy for the Clarion CII cochlear implant system.

Four postlinguistically deafened adults were implanted with the Clarion CII cochlear implant with the HiFocus II electrode in an evaluation of performance with a new speech coding strategy (high resolution) compared with current speech coding strategies (multiple pulsatile sampler, continuous interleaved sampling, and simultaneous analog stimulation). These strategies were implemented in the Platinum speech processor from Advanced Bionics Corporation (Sylmar, CA). Postoperatively, subjects were fitted with the traditional coding strategies and over the first month were allowed to determine their strategy of choice. This strategy was used to evaluate open-set speech recognition performance at 1 month and 3 months postfitting. At 3 months postfitting, subjects were reprogrammed with the high-resolution strategy. They returned for speech recognition testing at 1 month and 3 months postfitting with this strategy. Performance was significantly better with the high-resolution strategy for all four subjects, particularly when listening to speech in background noise. This finding was in agreement with their strong preference for the high-resolution strategy, and all four patients continue to use the high-resolution strategy.

Adult↗

PubMed1991

Experience with the Nucleus multichannel cochlear implant.

We have seen using the Nucleus multichannel cochlear implant since 1984, with more than 200 patients operated. Out of 152 adults, ten have ailed, either because of explants, or because of other causes especially psychological causes. Out of 53 children, only one child seldom wears his device. For the post-lingual adults, the vocal training is very short, during the three weeks hospitalisation necessary to place and to check the implant. The children need a much longer training period, which takes place in a special and pluridisciplinary cochlear implant center.

Adolescent↗

PubMed2001

Analysis of narrative ability in children with cochlear implants.

PURPOSE: The purposes of this study were to: 1) develop a scoring system to assess narrative ability in children; 2) evaluate the impact of auditory speech perception with a cochlear implant on narrative ability; and 3) evaluate the importance of narrative ability to reading comprehension in deaf children. DESIGN: Narrative productions prompted from an eight-picture sequence story were elicited from 8 and 9 yr olds; 87 who had at least 4 yr of cochlear implant experience and 28 who had normal hearing. The stories were transcribed and a scoring system for narrative ability was developed based on the use of complete narrative structure, conjunctions linking semantic relations, and referents that served to identify and distinguish characters in the narrative. Narrative ability scores of cochlear implant users were examined in relation to their age, IQ, speech perception, language, and reading test scores. In addition, narrative ability scores for children with normal hearing were compared with two groups of cochlear implant users, those with above average speech perception scores and those with below average speech perception scores. RESULTS: Within the sample of hearing-impaired children, narrative ability scores correlated significantly with speech perception, language syntax, and reading test scores. A multiple regression analysis was conducted to predict reading comprehension scores from four predictor variables (age, IQ, language syntax, and narrative ability). Results reflected the independent contribution of discourse-level language skills, as measured by the narrative ability score, as well as sentence-level language skills in predicting reading test scores. Analysis of stories obtained from 8- and 9-yr-old children with normal hearing revealed the classic pattern that included a high point, a resolution, and one or more evaluative statements. Their stories achieved cohesion from correct use of both conjunctions and referents. Deaf children who received above-average speech perception scores with a cochlear implant (i.e., scored above 48% on the Word Intelligibility by Picture Identification speech perception test) told narratives that were similar in structure and use of referents to those of age mates with normal hearing. Although their use of subordinate conjunctions was not as well developed as normal-hearing children, it was significantly above that of deaf children who received less speech perception benefit after a similar period of implant use. These below-average speech perceivers exhibited significantly poorer use of narrative structure and cohesive devices than either normal-hearing age mates or children who achieved above average speech perception with a cochlear implant. CONCLUSIONS: Narrative ability is an important predictor of reading comprehension ability in deaf children above and beyond IQ and syntactic competence. Children who receive a cochlear implant under 5 yr of age and obtain above average speech perception benefit from the device construct narratives that are similar in structure and cohesion to those of their hearing age mates by age 8 to 9.

Adolescent↗

PubMed2002

Surgical technique for the Nucleus Contour cochlear implant.

This paper deals with the Nucleus C124R (CS) (Contour) cochlear Implant: its characteristics, differences compared with the previous generation of devices, the perimodiolar electrode, and the surgical technique used for safe insertion. We also discuss the rationale behind perimodiolar electrodes in general, as well as the results of laboratory studies validating the design and safety of this particular electrode array. The differences in surgical technique between this device and prior Nucleus cochlear implants are as follows: the incision and the size of the well, or recess, for the electronics are smaller; the cochleostomy is larger; the posterior portion is placed in a subpericranial pocket, not tied down, before electrode insertion; and the insertion process itself is quite different, due to the nature of the electrode, its size, shape, and stylet. The technique described is that used by one experienced cochlear implant center, and reflect the authors' practice. Clearly, there are other possible variations on this theme, which may be equally satisfactory in other hands. Most surgeons find this device to be easier to place than previous generations: complications to date have been uncommon.

Acoustic Stimulation↗

PubMedDate not supplied

Cochlear implantation: strategies to protect the implanted cochlea from middle ear infection.

A cochlear implant for use in children must take into account the high incidence of middle ear infection in this age group. A scala tympani electrode that traverses the middle ear and round window will likely act as a conduit by which infection can spread to the inner ear and potentially to the CNS. In this study an attempt was made to reestablish a separation of the cochlea from the middle ear by developing a seal around the implant at the level of the round window. A series of cats were implanted with simulated cochlear prostheses consisting of either a plain Silastic cylinder, a Silastic cylinder wrapped with autogenous fascia, or a Silastic cylinder with a cuff of bioactive ceramic. Middle ear infection was induced, followed by histologic examination. Bioactive ceramic appears to have some merit as a round window sealing material, while fascia was shown to be of no value. Intracochlear infection, when it did occur, was limited to the basal regions of the cochlea.

Animals↗

PubMed2000

Outpatient cochlear implantation in the pediatric population.

Studies have shown that the incidence of complications in pediatric cochlear implant surgery is related to the age of the child, with a higher complication rate in younger patients. Consequently, many surgeons advocate admitting these children overnight. We began our pediatric cochlear implant program starting in June 1991 using the Nucleus 22-channel cochlear implant. To date, 65 children have undergone implantation, all on an outpatient basis. To evaluate safety, complication rate, and patient satisfaction, we gave the parents of the patients a questionnaire survey to complete. All patient charts were also retrospectively reviewed. More than 90% of parents surveyed responded that they were satisfied with the outpatient treatment of their children. There were no perioperative complications or readmissions. Cochlear implantation can be safely and effectively performed on an outpatient basis without an increase in morbidity. Day surgery reduces hospital costs at least $2500.

Adolescent↗

PubMed2000

[Intracochlear position of cochlear implant electrodes].

The insertion of cochlear implant electrodes in human temporal bones may be associated with the destruction of structures within the cochlea. The aim of this study was to measure such insertional trauma by means of histologic processing of implanted human temporal bones following implantation of a Combi 40/40+ electrode array (Med-El, Innsbruck). We implanted 6 human temporal bones with original electrodes (3 with Combi 40 and 3 with Combi 40+). In 4 bones Healon was used for electrode insertion. The histological investigation was performed after radiographic evaluation of the position of the electrode. For the histological procedure we used a technique which keeps the electrodes in position within the cochlea. In these slides we could clearly identify the electrodes in the tympanic scale. When inserted properly (point of first resistance) no trauma occurred in the basal portion of the cochlea and minimal trauma in the middle portion of the cochlea.

Cochlea↗

PubMed1994

Audiologic results with the MSP/MPEAK and WSP/F0F1F2 processors and coding strategies for the nucleus cochlear implant.

Seven Nucleus, multichannel, cochlear-implant recipients underwent a 4-week trial with a Research Speech Processor (RSP). For five users of the Wearable Speech Processor (WSPIII), the RSP consisted of a Mini Speech Processor (MSP) with a MultiPeak (MPEAK) coding strategy, and for two MSP users, a WSPIII, utilizing an F0F1F2 coding strategy was used. Scores on an auditory-only, speech perception test battery were used to compare performance with each device. Patients were evaluated with their own processor before and after their RSP experience, to assess potential practice effects. In general, the patients with higher baseline scores appeared to be better able to take advantage of the additional information provided by the MSP/MPEAK combination.

Acoustic Stimulation↗

PubMed2003

High resolution computed tomography and magnetic resonance imaging in the pre-operative assessment of cochlear implant patients.

Optimal imaging protocols for cochlear implantation have yet to be determined. Pre-operative computed tomography (CT) and magnetic resonance image (MRI) scans are used to assess cochlear anatomy and patency, to delineate surgical access, and to aid in choice of side for implantation. However, opinion still differs as to which modality provides more information in pre-operative assessment, or if, indeed, a combination of the two is superior. The first 88 patients on the Irish National Cochlear Implant Programme (NCIP) were retrospectively studied to determine the accuracy of pre-operative CT and MRI in predicting abnormalities at the time of surgery. Correlation with surgical findings was determined in three separate groups of patients (those who had CT only, those who had MRI only, and those who had both CT and MRI performed). Of the 24 patients that had both CT and MRI performed, both modalities had a 79 per cent correlation with surgical findings. CT and MRI reports concurred in 75 per cent of cases. Specificity and negative predictive value were high (86 per cent and 90 per cent, respectively). CT alone (47 cases) correlated with surgery in 39 cases (83 per cent); MRI alone (17 cases) correlated in 15 cases (88 per cent). The findings of this study suggest that CT and MRI are effective at predicting normal inner ear anatomy, and thus at predicting the patient and the cochlea most suitable for implantation. Both modalities are useful in determining the side of implantation, thus avoiding potential surgical difficulties in cases of unilateral abnormalities. There was no significant difference between the ability of MRI and CT to detect abnormalities at the time of surgery. In this series the combination of CT and MRI has not been shown to be superior to either modality used alone, although anecdotal evidence to the contrary was noted.

Adult↗

PubMed1995

Intonation of musical intervals by musical intervals by deaf subjects stimulated with single bipolar cochlear implant electrodes.

Some subjects with cochlear implants have been shown to associate electrical stimulus pulse rates with the pitches of musical tones. In order to clarify the role of these pitch sensations in a musical context, the present investigation examined the intonation accuracy achieved by implant subjects when adjusting pulse rates in the reconstruction of musical intervals. Using a method of adjustment, the subjects altered a variable pulse rate, relative to a fixed reference rate, on one electrode, in the tuning of musical intervals abstracted from familiar melodies. At low pulse rates, subjects generally tuned the intervals to the same frequency ratios which define tonal musical intervals in normal-hearing listeners, with error margins comparable to musically untrained subjects. Two subjects were, in addition, able to transpose these melodic intervals from a standard reference pulse rate to higher and lower reference rates (reference and target pulse rates with geometric means of the intervals ranging from 81 to 466 pulses/s). Generally, the intervals were adjusted on a ratio scale, according to the same frequency ratios which define analogous acoustical musical intervals. These results support the hypothesis that, at low pulse rates, a temporal code in the auditory nerve alone is capable of defining musical pitch.

Acoustic Stimulation↗

PubMed2006

Audiologic performance and benefit of cochlear implantation in Usher syndrome type I.

OBJECTIVE: The objective of this retrospective study was to evaluate the benefit and performance of cochlear implantation in patients with Usher syndrome type 1 (USH1). METHODS: Fourteen patients with a clinical diagnosis of USH1 were included. Mutation analysis of USH1 genes was performed in all of them. All patients filled in the G(C)BI questionnaire, which measures the benefit of implantation. In addition, equivalent hearing level scores (EHL) were calculated to measure performance. Correlations between the mentioned parameters were studied. RESULTS: One or two pathogenic mutations were identified in seven of the 14 examined patients. Similar to previous studies, it was demonstrated that implantation at an earlier age results in better performance than implantation at higher age. Cochlear implantation performed within the first 2 decades of life was beneficial to 13 of 14 (93%) of the patients with USH1. Finally, the EHL score and the G(C)BI score showed a significant correlation; the benefit of implantation increases with a decreasing EHL score. CONCLUSIONS: Cochlear implantation in patients with USH1 improves the audiologic performance when patients are implanted at an earlier age and is beneficial according to the G(C)BI when performed within the first 2 decades of life.

Adolescent↗

PubMed2005

Encoding frequency modulation to improve cochlear implant performance in noise.

Different from traditional Fourier analysis, a signal can be decomposed into amplitude and frequency modulation components. The speech processing strategy in most modern cochlear implants only extracts and encodes amplitude modulation in a limited number of frequency bands. While amplitude modulation encoding has allowed cochlear implant users to achieve good speech recognition in quiet, their performance in noise is severely compromised. Here, we propose a novel speech processing strategy that encodes both amplitude and frequency modulations in order to improve cochlear implant performance in noise. By removing the center frequency from the subband signals and additionally limiting the frequency modulation's range and rate, the present strategy transforms the fast-varying temporal fine structure into a slowly varying frequency modulation signal. As a first step, we evaluated the potential contribution of additional frequency modulation to speech recognition in noise via acoustic simulations of the cochlear implant. We found that while amplitude modulation from a limited number of spectral bands is sufficient to support speech recognition in quiet, frequency modulation is needed to support speech recognition in noise. In particular, improvement by as much as 71 percentage points was observed for sentence recognition in the presence of a competing voice. The present result strongly suggests that frequency modulation be extracted and encoded to improve cochlear implant performance in realistic listening situations. We have proposed several implementation methods to stimulate further investigation. Index Terms-Amplitude modulation, cochlear implant, fine structure, frequency modulation, signal processing, speech recognition, temporal envelope.

Algorithms↗