PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Cochlear Implants”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources
PubMed1990

[Cochlear implant--possibilities and limitations].

Provided that the auditory nerve is fully preserved and that the hearing impairment has not persisted for more than a few years, the cochlear implant offers a satisfactory, though not perfect, replacement for the defunct inner ear. Unfortunately, prior to operation, the residual function of the auditory nerve in patients with labyrinthine deafness cannot be determined quantitatively, but can merely be noted to be present or not. As the duration of the impairment lengthens, we must expect progressive degeneration of auditory nerve fibers, and increasing deprivation of the central auditory pathways. The limitations of cochlear implants are thus determined by an impairment that has persisted for decades, as also early-prelingual-development of the impairment. This also means that adults who were born deaf should not be recommended for the procedure. This should stimulate us all the more to create the conditions to ensure that the young deaf child can benefit from cochlear implantation at as early an age as possible. At the present time, we are attempting to work out surgical techniques and rehabilitative measures for cochlear implants in young deaf children.

Cochlear Implants↗
PubMed2001

Cochlear implantation in healthy and otitis-prone children: a prospective study.

OBJECTIVE: To evaluate and compare the timing of surgery, intraoperative findings, and otitis media-related outcome of cochlear implantation in children who are otitis-prone with their counterparts who are not otitis-prone. STUDY DESIGN: Prospective. METHODS: Children referred for cochlear implantation were assigned to a non-otitis-prone group (group A: normal otoscopy on their first visit after referral) or an otitis-prone group (group B: current or a recent history of otitis media at referral). Group B patients were managed using a structured protocol aimed at preimplantation otitis media control. The study reviewed pre-, intra-, and postoperative data. RESULTS: Of the 18 children studied, 8 were assigned to group A (mean age at referral, 40.6 mo) and 10 to group B (mean age at referral, 31.6 mo). For otitis media control, all otitis-prone children underwent ventilating tube insertion (various numbers of procedures before implantation). Only one otitis-prone child required cortical mastoidectomy also. Time from referral to implantation was similar in the two groups (mean, 6.6 mo). High-resolution computed tomography data showed mastoid pneumatization to be significantly smaller in the otitis-prone group, but the facial recess was not smaller in this group. During implantation, 10 children had inflamed middle ear mucosa. Seven of these belonged to group B. All of these seven children had a round window niche obliterated by the inflamed mucosa, which had to be removed for round window membrane identification. After implantation, only one child had drainage through the ventilating tube for more than 1 week. Two children in group B developed otitis media (1 year postimplantation) that was overcome within 1 week. There were no otitis media-related complications. CONCLUSIONS: If a structured protocol is used for the control of otitis media before cochlear implantation, otitis media should not require a delay in implantation. In otitis media-prone children, the round window niche is often obscured by inflamed mucosa. Its removal is mandatory for identification of the round window membrane. After cochlear implantation, otitis media is not a frequent occurrence.

Acute Disease↗
PubMed1999

[Rate discrimination and tone recognition in mandarin-speaking cochlear-implant listeners].

OBJECTIVE: To explore the relationship between the rate discrimination and the tone recognition with psychophysical method, and provide a basis for evaluating the results from mandarin-speaking cochlear implantees who used multi-channel cochlear implant and designing new speech coding strategies of the speech processor. METHODS: Four postlingually-deafened adults with cochlear implant participated in this study. We used the method of constant stimuli to measure the rate discrimination as a function of the standard rate at 50, 100, 200, 400 Hz on electrode pairs (E1, E3), (E7, E9), (E14, E16), and (E20, E22), respectively. We also measured tone recognition in 25 consonant-vowel syllables, each of which has four tonal variations, resulting in a total of 100 words. These words were recorded by a male talker and were presented five times each to the implant users via their speech processors. The tone recognition results were scored in overall percent correct and analyzed by error patterns in the confusion matrix and fundamental frequency. RESULTS: The rate discrimination thresholds, defined at the 75% correct level, varied greatly among individuals and ranged from several Hz to hundreds of Hz. A three-way ANOVA indicated significant effect (P < 0.05) on rate discrimination for the standard rate, electrode position, and patient variable. The tone recognition ranged from 40% to 80% and tones 1 and 3 were more easily identified than tones 2 and 4. Preliminary analysis using linear regression revealed highly significant correlation between rate discrimination and tone recognition. CONCLUSION: These results suggest that identification of tones relies on good rate discrimination in cochlear implant listeners. Clinical rehabilitation strategies in improving rate discrimination were discussed.

Adult↗
PubMedDate not supplied

Relation between vestibular function and speech recognition in postlingually deafened adults with cochlear implantation.

Thirty-one postlingually deafened adults with 22-channel cochlear implants were evaluated preoperatively using vestibular function tests, the caloric test and stabilometry. The results of caloric response were classified into two diagnostic groups: normo- or hyporeflexia and areflexia. Stabilometric recordings were made using a computerized static posturographic platform. Between the two categories of caloric response, there was a significant difference in consonant recognition, but the recognition of vowels showed no significant difference. The results of the distance of body sway in stabilometry, but not of the area, correlated to the results of consonant recognition in speech perception tests. The degree of residual vestibular function seems to be one of the indicators influencing postoperative speech recognition by cochlear implant patients.

Adult↗
PubMed2001

Cross-modal plasticity underpins language recovery after cochlear implantation.

Postlingually deaf subjects learn the meaning of sounds after cochlear implantation by forming new associations between sounds and their sources. Implants generate coarse frequency responses, preventing place-coding fine enough to discriminate sounds with similar temporal characteristics, e.g., buck/duck. This limitation imposes a dependency on visual cues, e.g., lipreading. We hypothesized that cross-modal facilitation results from engagement of the visual cortex by purely auditory tasks. In four functional neuroimaging experiments, we show recruitment of early visual cortex (V1/V2) when cochlear implant users listen to sounds with eyes closed. Activity in visual cortex evolved in a stimulus-specific manner as a function of time from implantation reflecting experience-dependent adaptations in the postimplant phase.

Acoustic Stimulation↗
PubMed1999

Enhancing the speech envelope of continuous interleaved sampling processors for cochlear implants.

A new method to code the speech envelope in continuous interleaved sampling (CIS) processors for cochlear implants is proposed. In this enhanced envelope, the rapid adaptation seen in the response of auditory nerves to sound stimuli is incorporated. Two strategies, one using the standard envelope (CIS) and one using the enhanced envelope (EECIS), were tested perceptually with six postlingually deafened users of the LAURA cochlear implant. The tests included identification of stop consonants in three different vowel contexts and monosyllabic consonant-vowel-consonant (CVC) words. Significant improvements in correct identification scores were observed for stop consonants in intervocalic /a/ context (p = 0.026): average results varied from 46% correct for CIS to 55% for EECIS. This improvement was mainly due to the better transmission of place of articulation. The differences in identification scores for stop consonants in /i/ and /u/ context were not significant. The identification scores for the medial vowels of the CVC words were significantly higher when the EECIS strategy was used: average results increased from 39% correct to 46% correct (p = 0.018). No significant differences were observed between the results for initial and final consonants of the CVC words. The present results demonstrate that the inclusion of the rapid adaptation in the speech processing for cochlear implants can improve speech intelligibility.

Adolescent↗
PubMed2005

Is mastoidectomy indispensable in cochlear implant surgery?

OBJECTIVE: To challenge the need for mastoidectomy in cochlear implant (CI) surgery by comparing the advantages and disadvantages of the classic technique for CI, the mastoidectomy posterior tympanotomy approach (MPTA), with the suprameatal approach (SMA), a nonmastoidectomy approach. STUDY DESIGN AND SETTING: A retrospective study of 290 patients who underwent cochlear implantation in our department between 1989 and 2002. One hundred fifty-seven of them underwent the MPTA and 133 underwent the SMA. The ability of the electrode to expand in the MPTA patients who were reoperated on was examined, as was the influence of mastoidectomy on the course of chronic secretory otitis media (SOM) in a group of 56 children who suffered from chronic SOM prior to implantation. RESULTS: In all 4 reoperated children, in whom the MPTA was used, the mastoid was completely closed by bony regrowth on the cortical portion of the mastoid and the mastoid cavity was obliterated. The electrode had been embedded in dense fibrous tissue and bony spicule, preventing electrode expansion. Mastoidectomy was found to have no influence on the course of chronic SOM. The rate of postoperative SOM was found to be equal in 40 children who were operated on using the MPTA compared with 16 operated on using the SMA. CONCLUSION: Using a nonmastoidectomy approach, such as the SMA, provides a wide exposure of the middle ear and promontory and thus enables a well-controlled cochleostomy site and safe insertion of the electrode into the cochlea. Mastoidectomy in CI surgery is not indispensable; it may cause more disadvantages than advantages.

Adolescent↗
PubMed1995

Cochlear implants.

Explore the source record for details and available documents.

Cochlear Implants↗
PubMed2004

[Caloric stimulation of the vestibular organ after cochlear implant surgery].

BACKGROUND: Alterations of the vestibular organ after intracochlear insertion of the electrode array in cochlear implant (CI) surgery are estimated in the literature to be more than 30 % . By performing a most atraumatic electrode insertion following the "soft surgery technique" as described by Lehnhardt , the risk of postoperative vestibular dysfunction should be minimised. METHODS: In the present study we compared pre- and postoperative results of the caloric stimulation test in cochlear implant patients and analysed the influence of untimely opening of the perilymphatic space under cochleostomy. In addition we used a non-validated questionnaire, asking for continuous postoperative vertigo after cochlear implant surgery. RESULTS: From patients with preoperative normal or hyperfunction on the implanted ear (n = 32) approximately 16 % showed a hypofunction or nonfunction on the implanted side postoperatively, independent of the technique of the cochleostomy. Only 12 % (n = 98) of the patients who were without vestibular problems preoperatively described postoperative vertigo longer than two days in the questionnaires. CONCLUSIONS: Although we found no significant difference regarding the influence of the technique of the cochleostomy on the preservation of vestibular function, we conclude that the concept of an atraumatic electrode insertion reduces the risk of vestibular dysfunction after CI-surgery.

Adolescent↗
PubMed2005

Effects of cochlear implant use on the electrically evoked middle latency response in children.

The electrically evoked middle latency response (eMLR) reflects central auditory activity in cochlear implant users. This response was recorded repeatedly in 50 children over the first year of cochlear implant use and in 31 children with 5.3+/-2.9 years of implant experience. The eMLR was rarely detected at the time of implantation in anaesthetized or sedated children and was detected in only 35% of awake children at initial device stimulation. The detectability of the eMLR increased over the first year of implant use becoming 100% detectable in children after at least one year. Acutely evoked responses were more likely to be present in older children despite longer periods of auditory deprivation. Within six months of implant use, most children had detectable eMLRs. At early stages of device use, eMLR amplitudes were lower in children implanted below the age of 5 years compared to children implanted at older ages; amplitudes increased over time in both groups. Latencies after six months of implant use were prolonged in the younger group and decreased with implant use. EMLR changes with chronic cochlear implant use suggest an activity-dependent plasticity of the central auditory system. Results suggest that the pattern of electrically evoked activity and development in the auditory thalamocortical pathways will be dependent upon the duration of auditory deprivation occurring in early childhood.

Adolescent↗
PubMed1996

Evaluation of MRI compatibility of the modified nucleus multichannel auditory brainstem and cochlear implants.

Magnetic resonance imaging (MRI) has been contraindicated for users of cochlear implants because of the internal magnet and other possible interactions. Users of the Nucleus Mini-22 Cochlear Implant (CI) or the experimental Multichannel Auditory Brainstem Implant (ABI) may have other disorders that are best diagnosed by MRI. The CI and ABI were modified by replacing the internal magnet and integrated circuit lid with nonmagnetic material. Tests were conducted in a 1.5-T MRI machine. Safety tests for force, heating, induced current, unintentional implant output, and implant damage were conducted by using various phantom models. Image distortion was evaluated in two subjects with implants. The maximum force measured was 2,818 dynes. There was < 0.1 degree C temperature increase in the vicinity of the implant. The maximum induced charge was > or = 667 times less than the minimum charge for auditory stimulation. There was no unintentional output during MRI scans and no change in implant function after 10 repeated scans. Image distortion consisted primarily of darkening and was worst in the axial plane, where it extended 1-2 cm medially and inferiorly from the receiver/stimulator. Compatibility-test results were acceptable, with a large margin of safety. Image distortion is limited to darkening in the immediate vicinity of the implant.

Adult↗
PubMed2005

Device nonuse among adult cochlear implant recipients.

OBJECTIVE: To examine the causes and prevalence of previous and current device nonuse among adults who have received cochlear implants. STUDY DESIGN: Retrospective case review. SETTING: Adult tertiary referral center for cochlear implantation. METHODS: Two hundred fourteen consecutively implanted adult patients. The length of implant use ranged from 1 month to 14 years. MAIN OUTCOME MEASURE: A period of 4 consecutive weeks of nonuse of cochlear implant, including both obligatory and elective nonuse. RESULTS: Twenty-nine adults (13.6% of implantees) were identified as having at some stage not used their device for a period of more than 4 consecutive weeks. The main reason was device failure (n = 11). Ten adults are current nonusers (4.7% of implantees). Reasons include surgical complication necessitating explantation (n = 3), comorbid illness (n = 3), elective nonuse (n = 2), audiologic complication (n = 1), and device failure (n = 1). CONCLUSION: The overall prevalence of device nonuse was noted to increase slowly with time. The role of psychologic factors in contributing to the decision of an individual to elect to opt out of device use remains unproven.

Adolescent↗
PubMed2005

The efficacy of a structured group therapy intervention in improving communication and coping skills for adult cochlear implant recipients.

This paper reports on an evaluation of a structured group therapy intervention for adult cochlear implant (CI) recipients designed to improve overall communication and coping skills. 33 adult CI recipients (14 males, 19 females; mean age 61; 1-14 years since Cl) participated in a 2-day structured group therapy intervention with a follow-up session 4 weeks later. Measures were: communication behaviors (CPHI), assertiveness (Rathus), depression (DASS), and behavior during conversation (Dyalog). TCI personality traits were utilized as predictors of change. Repeated measures analyses showed that participants demonstrated significant improvements on measures of assertiveness, emotional well-being, and coping behaviors at 3 months post-intervention that persisted at a 12-month follow-up. Several personality traits predicted change. Although subjects had presumably adapted to their cochlear implants and had learned communication strategies in hearing rehabilitation programs, the improvements on several measures suggest that a structured group therapy intervention can enhance outcome following cochlear implantation.

Adaptation, Psychological↗
PubMed2003

Language skills of children with early cochlear implantation.

OBJECTIVE: This study investigated factors contributing to the comprehension and production of English language by children with prelingual deafness after 4 to 7 yr of multichannel cochlear implant use. The analysis controlled for the effects of child and family characteristics so that educational factors most conducive to maximum implant benefit could be identified. DESIGN: A battery of language tests were administered to 181 8- and 9 yr-old children from across the United States and Canada who received a cochlear implant by age 5. Tests of comprehension, verbal reasoning, narrative ability and spontaneous language production were administered either in speech and sign or in the child's preferred communication mode. These constituted the Total Language measures. Spoken Language measures were derived from a speech-only language sample. Type and amount of educational intervention since implantation constituted the independent variables. Characteristics of the child and the family were considered intervening variables. A series of multiple regression analyses determined the amount of variance in Total Language and Spoken Language ability accounted for by the intervening variables and the amount of additional variance attributable to the independent variables. RESULTS: More than half of the children (with performance intelligence quotients in the average range) exhibited language skills that were similar to those of hearing 8 to 9 yr olds on measures of verbal reasoning, narrative ability, utterance length, and lexical diversity. Significant predictors of language ability were similar for Total and for Spoken Language outcomes and included greater nonverbal intelligence, smaller family size, higher socio-economic status and female gender. Age at receiving an implant did not affect language outcome. After the variance due to these variables was controlled, the primary rehabilitative factors associated with linguistic outcome were amount of mainstream class placement and an educational emphasis on speech and auditory skills. CONCLUSIONS: Use of a cochlear implant has had a dramatic impact on the linguistic competence of profoundly hearing-impaired children. More than half of the children in this sample with average learning ability produced and understood English language at a level comparable with that of their hearing age mates. Such mature language outcomes were not typical of children with profound hearing loss who used hearing aids. Use of a visual (i.e., sign) language system did not provide the linguistic advantage that had been anticipated. Children educated without use of sign exhibited a significant advantage in their use of narratives, the breadth of their vocabulary, in their use of bound morphemes, in the length of their utterances and in the complexity of the syntax used in their spontaneous language. An oral educational focus provided a significant advantage for both spoken and total language skills.

Canada↗
PubMed2004

Incisions for cochlear implant flaps and superficial skin temperature. Skin temperature/blood circulation in CI flaps.

Healing and integration of a cochlear implant is largely influenced by good blood circulation in the covering skin, which, on the other hand, is closely correlated to skin temperature. Measuring superficial flap temperatures by thermography is an easy way to get some clues about the corresponding blood supply. These data should allow some implications for the design of skin flaps in cochlear implant surgery. In 15 patients thermography was carried out prior to and after cochlear implantation, using the Agema 550 Thermovision system. It was evident, that the anatomic courses of the major superficial arteries were represented by areas of increased temperature. The pattern of temperature distribution may allow some conclusions concerning site and shape of surgical incisions. From our data we concluded, that most types of incisions do not interfere too much with the arterial blood supply. However, some types like the extended retroauricular C-incision may eventually cause problems. Our data suggest, that the straight or slightly curved vertical retroauricular incision causes the least impairment of blood circulation. After surgery, directly along the incisions (and later along the scars) temperature was diminished, indicating reduced blood circulation. In our series, the thickness of the implant did not impede blood circulation significantly. So far, we could not examine patients with local circulation disorders. Probably local scars, skin atrophies, angiopathies etc. may present typical patterns of temperature distribution, which require individual design of skin flaps. Thermography is an easy method which can give impressions of local blood circulation in skin flaps. If the courses of the major arteries and their branches are respected, blood circulation within the flap should not be problematic. Thermography is likely to help designing optimal flaps in cases with impeded blood circulation e.g. by pre-existing scar formations.

Atrophy↗
PubMed1998

Psychological change over 54 months of cochlear implant use.

OBJECTIVE: To determine the long-term psychological outcome of postlingually deafened adults who received multichannel cochlear implants and to relate the psychological outcome to audiological outcome. DESIGN: Thirty-seven recipients of multichannel cochlear implants who participated in a prospective clinical trial completed psychological assessments before implantation and at regularly scheduled follow-ups through 54 mo of implant use. Standardized measures of affect, social function, and personality were used, and scores on these measures were correlated with asymptotic scores on several audiological measures. RESULTS: Evidence of significant improvement on measures of loneliness, social anxiety, and distress were obtained within a year after implantation and throughout the duration of the follow-up period. For measures of assertiveness and marital satisfaction, improvement was apparent only after long-term implant use. Although favorable changes on the Minnesota Multiphasic Personality Inventory (MMPI) Depression Scale were evidenced only in the initial follow-up period, improvements on the MMPI Paranoia and Social Introversion Scales persisted throughout the 54 mo follow-up. CONCLUSION: Multichannel cochlear implant use is associated with long-term psychological benefit. Correlations between audiological outcome and psychological outcome, however, suggested that the relation between audiological benefit and psychological benefit is not simple.

Adult↗