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At least 433 records · Page 24Linked to original sources

PubMed2002

Tone discrimination in Cantonese-speaking children using a cochlear implant.

Most tone perception tests for Cantonese-speaking cochlear implant users have been based on tone identification tasks which require significant cognitive development to be successfully completed. Results from such tests suggest that cochlear implant child users are performing at about chance level and may not be receiving much information about pitch using the implant. This paper reports on the ability of cochlear implant child users to discriminate pitch variations in Cantonese by using an experimental procedure based on play audiometry. As part of the study, the usefulness of higher rates of electrode stimulation for aiding tone discrimination is also examined. Cochlear implant users are shown to derive sufficient information about pitch to discriminate most tone contrasts relatively successfully, with performance being most variable for contrasts involving tones clustered in the lower register of the speaker's fundamental frequency range. Contrary to hypothesis, higher electrode stimulation rates are not found to offer significant benefits for aiding pitch discrimination.

Child↗

PubMed2006

Cochlear implants in Waardenburg syndrome.

OBJECTIVE: Waardenburg syndrome is an autosomal-dominant syndrome characterized by dystopia canthorum, hyperplasia of the eyebrows, heterochromia irides, a white forelock, and sensorineural hearing loss in 20% to 55% of patients. This patient population accounts for approximately 2% of congenitally deaf children. The purpose of this retrospective case review was to describe the outcomes for those children with Waardenburg syndrome who have undergone cochlear implantation. METHODS: Pediatric cochlear implant recipients with documented evidence of Waardenburg syndrome underwent retrospective case review. All patients received their cochlear implants at the study institution followed by outpatient auditory habilitation. Charts were reviewed for etiology and duration of deafness, age at time of cochlear implantation, perioperative complications, duration of use, and performance outcomes. Results of standard tests batteries for speech perception and production administered as a part of the patients' auditory habilitation were reviewed. RESULTS: Seven patients with Waardenburg syndrome and cochlear implants were identified. The average age at implantation was 37 months (range, 18-64 months) and the average duration of use was 69 months (range, 12-143 months). All of these patients are active users of their devices and perform very well after implantation. There were no major complications in this small group of patients. CONCLUSIONS: Children with congenital sensorineural hearing loss without other comorbidities (e.g., developmental delay, inner ear malformations) perform well when they receive cochlear implantation and auditory habilitation. Patients with Waardenburg syndrome can be expected to have above-average performance after cochlear implantation.

Child, Preschool↗

PubMed2005

Cochlear implantation in otosclerosis.

OBJECTIVE: The purpose of this study was to evaluate and compare the results obtained in a group of implanted otosclerotic patients with a group of cochlear implant (CI) patients not affected by otosclerosis. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Nine patients affected by profound sensorineural hearing loss caused by otosclerosis and nine patients affected by profound sensorineural hearing loss not caused by otosclerosis were evaluated. INTERVENTION: Cochlear implantation. MAIN OUTCOME MEASURES: Preoperative imaging, intraoperative findings, postoperative facial nerve stimulation, and speech perception performance measures were performed and the data analyzed. RESULTS: Otosclerosis patients showed signs of cochlear ossification both on high-resolution computed tomography scans and intraoperatively. The incidence of facial nerve stimulation was higher in the otosclerosis group, three out of nine, and was generally related to the use of electrical stimulation from the Nucleus 22 cochlear implant. Psychophysical and speech perception measures did not show significant differences between the two groups, despite some otosclerosis patients showing increased electrical thresholds and comfort levels and slightly poorer speech perception performance scores. CONCLUSIONS: Patients with otosclerosis who have progressed to profound hearing loss derive significant benefit from cochlear implants; however, an increased risk of cochlear ossification and facial nerve stimulation has to be taken in account during preoperative counseling. The advance in imaging techniques, CI technology and the possibility to stimulate precise regions of the cochlea with lower intensities make it possible for the surgeons and audiologists to readily and successfully manage these complications as they arise.

Adolescent↗

PubMed1984

Preliminary assessment of the Los Angeles, Vienna and Melbourne cochlear implants.

We tested four patients using the single-channel cochlear implant from Los Angeles, three patients using the single-channel cochlear implant from Vienna, and two patients using the multichannel cochlear implant from Melbourne. Tests from the MAC battery and the Iowa Cochlear Implant Battery were used. Most patients were able to identify some environmental sounds. Three of the patients had difficulty distinguishing between male and female voices, and three could not distinguish between a noise and a voice. All patients had difficulty discriminating between unknown speakers of the same sex. A four-choice spondee test in noise showed that all patients suffered drastically from background noise. In all cases there was an improvement in lipreading ability with the implant. On a sentence test with a contextual cue seven patients got some words with sound alone. Results obtained with the multichannel implant are superior on several tasks, but we have tested too few patients to allow us any firm conclusions.

Auditory Perception↗

PubMed1999

The effect of frequency allocation on phoneme recognition with the nucleus 22 cochlear implant.

HYPOTHESIS: Phoneme recognition performance in patients implanted with the Nucleus 22 cochlear implant is affected by the frequency-to-electrode assignment. BACKGROUND: Multiple electrodes in modern cochlear implants are intended to deliver frequency-specific information to different tonotopic locations along the cochlea. However, the relation between the electrode locations, distribution of frequency information, and performance has not been explored thoroughly. METHODS: Ten listeners were tested on vowel and consonant identification tasks immediately after receiving each of the 15 speech processors. Experimental processors were created with 4, 7, and 20 activated electrodes. Five different frequency allocations were tested with all electrode conditions. RESULTS: For 7- and 20-electrode maps, best vowel recognition performance was obtained with frequency tables 7 and 9, with subjects showing best performance with the table with which they were most familiar. With 4-electrode maps, no change in vowel recognition performance was observed as a function of the frequency allocation. Consonant scores showed only a small effect of frequency allocation across all processors. Results were similar across listeners with different electrode insertion depths. CONCLUSION: The allocation of frequency ranges to electrodes in the Nucleus-22 cochlear implant can affect vowel recognition, when more than four electrodes are used, but is less important for consonant recognition. The allocation of frequency ranges to electrodes is an important factor in multichannel implants with more than four electrodes. The similarity of results across implant listeners with different electrode insertion depths implies that the optimal frequency allocation is one that best matches the allocation to which they've become accustomed, rather than one that matches the original tonotopic location of the electrodes.

Adult↗

PubMed2004

Chronological changes of stimulation levels in prelingually deafened children with cochlear implant.

This study investigated changes in long-term cochlear implant MAPs (values of the program to stimulate electrodes) in children, and examined whether there were significant differences between children and adults. Ten prelingually deafened children (aged from 2.7 to 7.8 years) who received the Nucleus 22 cochlear implant at Kyoto University between 1996 and 1998 participated in this study. Behavioral thresholds (T levels) and maximal comfortable levels (C levels) were evaluated at 3 months post-implant, and then every 6 months up to 4 years. Ten adult cochlear implant users were also evaluated as a control group. All subjects had used their implant for at least 4 years after device connection. All prelingually deafened children demonstrated slower but continuous improvements in speech perception and production abilities during the test period. T levels became stable at 30 months post-implant in children and at 24 months post-implant in adults. C levels became stable at 6 months post-implant in children and within 3 months post-implant in adults. In conclusion, T levels of prelingually deafened children became stabilized 30 months post-implant, while C levels stabilized 6 months post-implant. MAPs of prelingually deafened children were stabilized 30 months post-implant, which was longer than that in adult cochlear implant users.

Adult↗

PubMed1996

A new concept for Cochlear implant speech processing.

OBJECTIVE: A new speech processing concept and its implementation cochlear implant neural net, simulation and stimulation (CINSTIM), for cochlear implant systems is currently under investigation. The main objectives of this new strategy are to improve speech perception within the early rehabilitation period for prelingually deaf cochlear implant users and to improve speech perception in noise for all implant users. The advantage of this approach is the capability to assess and compare entirely different speech processing methods within the existing implant hardware. DESIGN: The processing concept is based on discrete sequences of distinguishable stimulus patterns, robust speech processing, and a classifier. The embedded Kohonen classifier employs unsupervised neural net algorithms. RESULTS: Initial experimental results have validated the general processing scheme as well as the development of this complex software. In addition, a limited alphabet of distinguishable stimulus patterns was achieved and assessed with experienced users of a conventional cochlear implant system. Test subjects were able to learn and recognize up to 60% of these artificial patterns after a few training sessions. Currently this speech processing strategy is being evaluated through the Cochlear MSP system; however, it is compatible with the other computer driven digital cochlear implant systems.

Cochlear Implants↗

PubMed2003

Clinical relevance of the distance between the cochlea and the facial nerve in cochlear implantation.

HYPOTHESIS: To elucidate possible mechanisms of facial nerve costimulation after cochlear implantation that are supposed to result from the close cochlea to facial nerve contact. BACKGROUND: One of the postoperative complications of cochlear implantation is facial muscle twitching, which has preferentially been found in otosclerotic patients. It impairs hearing benefits because of deactivation of electrodes and can still not be adequately prevented. METHODS: A total of 13 temporal bones were dissected to quantify where the labyrinthine portion of the facial nerve is closest to the scala tympani, the placement site of the cochlear implantation electrode array. After the typical operative procedures to find out the number of electrodes lying closest to the facial nerve were performed, a cochlear implantation array was inserted into four specimens. The clinical records of 14 otosclerotic patients were investigated to correlate these results with the position of in vivo deactivated electrodes. RESULTS: The closest distance between the scala tympani and the nerve was only 0.33 mm (+/-0.14). On average, after insertion of 23 electrode resp. marking rings, the facial nerve was reached. This is clinically the position of most frequently deactivated electrodes to prevent postoperative facial nerve costimulation. CONCLUSIONS: These investigations support the hypothesis that a direct current spread at the site of the facial nerve crossing the cochlear basal turn is most likely the reason for postoperative facial muscle twitching facilitated in otospongiotic bone. Prevention could therefore be achieved by cochlear implantation designs and surgical techniques that take into consideration the site of closest contact.

Adult↗

PubMed2003

Connected speech intelligibility of children with cochlear implants and children with normal hearing.

The objective of this study was to compare the connected speech intelligibility of children who use cochlear implants with that of children who have normal hearing. Previous research has shown that speech intelligibility improves from before cochlear implantation to after implantation and that the speech intelligibility of children who use cochlear implants compares favorably with that of children who use conventional hearing aids. However, no research has yet addressed the question of how the speech intelligibility of children who use cochlear implants compares to that of children with normal hearing. In the current study, archival data on connected speech intelligibility from 51 children with cochlear implants were compared with newly collected data from 47 children with normal hearing. Results showed that for children with cochlear implants, greater intelligibility was associated with both increased chronological age and increased duration of cochlear implant use. Consistent with previous studies, children with normal hearing achieved adult-like or near-adult-like intelligibility around the age of 4 years, but a similar peak in intelligibility was not observed for the children who used cochlear implants. On the whole, children with cochlear implants were significantly less intelligible than children with normal hearing, when controlling both for chronological age and for length of auditory experience. These results have implications for the socialization and education of children with cochlear implants, particularly with respect to on-time placement in mainstream educational environments with age peers.

Child↗

PubMed1987

Cochlear implants in deaf children.

The results to date with the 3M/House cochlear implant in children have been extremely encouraging. Statistically and clinically significant changes show that the implant can provide improvements in auditory detection and discrimination as well as in speech production. As with any intervention, results range from outstanding for some children (open-set speech discrimination and/or intelligible speech) to minimal for others (no stimulation or little improvement in speech). Until long-term studies can be completed, the implant will undoubtedly remain controversial. However, professionals involved in the care of a child who is hearing-impaired should be informed that the field of cochlear implantation is rapidly expanding. A number of different cochlear implants are currently undergoing clinical trials in adults. Besides the 3M/House device, the FDA has recently approved a second device, the Nucleus Multichannel Cochlear Implant, for investigation in children. The treatment of profound deafness is changing in children with the cochlear implant as an option for those not benefiting significantly from hearing aids. However, some important aspects of a deaf child's management have not changed and will not change: the need for early diagnosis and multidisciplinary management. The first five years of life are the language acquisition years. Proper management during these years is critical if the hearing-impaired child's handicap is not to dominate his or her future and limit potential for a successful, happy life.

Adolescent↗

PubMed1989

[Single channel cochlear implant: application to three patients].

Single channel cochlear implant of 3M/House design was implanted to the three patients with profound hearing loss. Before the implantation, use of hearing aid had not afforded serviceable hearing enough for speech recognition in these patients. Postoperative courses were uneventful. Speech rehabilitation was started at 3 weeks after the surgery. The speech tracking scores with the cochlear implant plus lipreading achieved 20-25 bunsetues (the minimum meaningful unit of the Japanese sentence) per minute at three or four months after the operation. All the patients could recognize speech of daily life with help of lipreading. However, speech recognition by the cochlear implant alone was not satisfactory.

Adult↗

PubMed2006

Cochlear implant and vestibular function.

OBJECTIVES: To document incidences of vestibular dysfunction after cochlear implantation and investigate why it occurs. This work was also motivated by a desire to provide the basis for better preoperative counseling and postoperative vestibular therapy to cochlear implant patients. SETTING: Melbourne Cochlear Implant Clinic at a tertiary referral hospital. STUDY DESIGN: Prospective observational study. PATIENTS: One hundred forty-six adult implant recipients, mean age, 60 years (range, 20-90 yr). MAIN OUTCOME MEASURES: Postoperative vestibular disturbance was defined as symptoms lasting for 1 week or longer after surgery. The differences in preoperative and postoperative vestibular function were measured from subjective assessments (Dizziness Handicap Inventory and Activity Balance Confidence questionnaires) and objective assessments (bithermal caloric tests). The position of the postoperative electrode was classified as "loose", "regular", or "tight" fitting. RESULTS: Thirty-two percent of patients reported vestibular disturbance and had poorer Dizziness Handicap Inventory, Activity Balance Confidence, and caloric results in the implanted ear after surgery. Patient age, cause, and preoperative caloric result did not predict postoperative vestibular symptoms. Recipients aged 70 years or older had significantly poorer caloric results on the implanted side after surgery that was not related to the intracochlear electrode position or surgical team. CONCLUSION: One-third of recipients can expect to experience a significant vestibular disturbance after surgery, regardless of age, cause, or preoperative caloric result. "Older" ears seem more prone to permanent injury after cochlear implantation.

Adult↗

PubMed1990

Endoscopy of the cochlea during cochlear implantation.

We have previously demonstrated that multichannel cochlear implants may be effective in partially obstructed cochleas. In practice, however, it may be difficult to determine whether electrode insertion is feasible prior to attempting it. Initial trials with a flexible fiberoptic otologic endoscope on 10 cadaver temporal bones were previously reported. On the basis of these trials, endoscopy of the inferior segment of the cochlea during cochlear implantation seemed feasible. In the present study, the same endoscope was used on eight subjects undergoing cochlear implantation, six of whom had partially obstructed cochleas. Endoscopy was found to be helpful in visualizing obstructed segments, determining patency after the obstruction was removed, and identifying normal structures of the cochlea. Documentation with videotape and 35-mm photography constitutes the majority of this paper.

Adolescent↗

PubMed1994

[Testing of synthetic vowels in patients with 22 channel cochlear implant].

In the 22 multi-channel cochlear implant system, F0 information determines the frequency of electrical stimulation, and F1 and F2 information determine the number of stimulating electrodes. We performed tests using synthetic vowels on 16 patients who had undergone 22 channel cochlear implant surgery and 6 months' speech rehabilitation. Information transmission rates were calculated to analyze the response pattern. As a result, 1) the vowel recognition ability of patients with cochlear implant surgery correlated with the number of electrodes being used. 2) The value of vowel confusion decreased so as to be separated by a pair of stimulating electrodes, and the confusion in F1 information was regarded to be less than that for F2 information.

Adolescent↗

PubMed2002

Cochlear implantation in chronic suppurative otitis media.

OBJECTIVE: To evaluate management options for cochlear implantation in patients with chronic suppurative otitis media. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center with a large cochlear implant program. PATIENTS: Ten patients with chronic suppurative otitis media who received cochlear implants were identified. Case history, etiology of hearing loss, and management of the ear with the implant were evaluated. INTERVENTIONS: Cochlear implantation and subsequent rehabilitation. MAIN OUTCOME MEASURES: Early and late complications were evaluated. RESULTS: No early or late complications were identified in this group of patients after an average follow-up period of about 4 years. CONCLUSION: Cochlear implantation can be safely achieved in patients with chronic suppurative otitis media. There are several options for the management of these patients, and the approach chosen should be individualized on the basis of clinical findings.

Adolescent↗

PubMed2005

Blink reflex and auditory speech perception in prelingually cochlear-implanted children.

CONCLUSION: The results of this study show that R- prelingually cochlear-implanted children are not optimal candidates for cochlear implantation. However, if this group are implanted, other rehabilitation methods should be incorporated into their rehabilitation program in order to achieve better results and maximize the efficacy of their prosthesis. OBJECTIVE: To demonstrate that the blink reflex or auropalpebral reflex evaluation can be used as a prognostic factor for the assessment of auditory and speech perception levels in prelingually cochlear-implanted children. MATERIAL AND METHODS: In an observational, analytical, prospective study conducted at a single cochlear implant rehabilitation center in 85 prelingually cochlear-implanted children, the presence or absence of the blink reflex (BR) was evaluated and the results of auditory and speech perception tests were compared between reflex-positive (R+) and reflex-negative (R-) patients. To obtain the BR, four electrodes were applied in both the Nucleus and MED-EL systems and then stimulated by means of current levels higher than the previously detected most comfortable level of the patient until the reflex appeared. Auditory and speech perception levels were measured using the vowels-confusion test and the categorization of auditory perception scale. RESULTS: The mean results of auditory and speech perception tests were significantly higher in R+ compared to R- patients.

Auditory Threshold↗

PubMed2006

Solutions to electromagnetic interference problems between cochlear implants and GSM phones.

For persons using cochlear implants, electromagnetic compatibility (EMC) problems may sometimes be an obstacle to using digital cellular telephones. This study aimed at exploring the benefit of three new assistive listening device prototypes that eliminate or diminish EMC problems. Ten experienced cochlear implant users listened in quiet to running speech samples and a sentence test on a landline phone, a digital cellular phone with and without three prototypes. The subjects' performance was assessed using a sentence test, a subjective visual analog scale, and by ranking the best and the poorest listening condition. Compared to the other test conditions, listening to a digital cellular phone alone revealed, on average, the poorest sentence recognition scores (29%) and the poorest results in four different subjective judgments (the amount of disturbances, the clarity of the message, the quality of the sound, overall judgment) with all three implant systems tested. The prototypes generally helped the implantees to recognize speech better on the cellular telephone (by 10-21 percent units, on average). Use of assistive listening devices and further development of EMC of both cochlear implant systems and digital cellular phones needs to take place to enable smooth use of digital cellular phones for all implantees.

Adult↗

PubMed2006

The consequences of neural degeneration regarding optimal cochlear implant position in scala tympani: a model approach.

Cochlear implant research endeavors to optimize the spatial selectivity, threshold and dynamic range with the objective of improving the speech perception performance of the implant user. One of the ways to achieve some of these goals is by electrode design. New cochlear implant electrode designs strive to bring the electrode contacts into close proximity to the nerve fibers in the modiolus: this is done by placing the contacts on the medial side of the array and positioning the implant against the medial wall of scala tympani. The question remains whether this is the optimal position for a cochlea with intact neural fibers and, if so, whether it is also true for a cochlea with degenerated neural fibers. In this study a computational model of the implanted human cochlea is used to investigate the optimal position of the array with respect to threshold, dynamic range and spatial selectivity for a cochlea with intact nerve fibers and for degenerated nerve fibers. In addition, the model is used to evaluate the predictive value of eCAP measurements for obtaining peri-operative information on the neural status. The model predicts improved threshold, dynamic range and spatial selectivity for the peri-modiolar position at the basal end of the cochlea, with minimal influence of neural degeneration. At the apical end of the array (1.5 cochlear turns), the dynamic range and the spatial selectivity are limited due to the occurrence of cross-turn stimulation, with the exception of the condition without neural degeneration and with the electrode array along the lateral wall of scala tympani. The eCAP simulations indicate that a large P(0) peak occurs before the N(1)P(1) complex when the fibers are not degenerated. The absence of this peak might be used as an indicator for neural degeneration.

Action Potentials↗