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 1,495 records · Page 83Linked to original sources
PubMed2005

Influence of ionizing radiation on nucleus 24 cochlear implants.

HYPOTHESIS: To evaluate the influence of conventional or hyperfractionated radiotherapy on Nucleus CI24M or CI24R(CS) implant systems. BACKGROUND: As a consequence of more than 70,000 cochlear implant recipients worldwide, the potential need for radiotherapy is an issue requiring consideration by both implantees and implantation centers. Conditions requiring radiotherapy of the head may include head, neck, or brain tumors. METHODS: The study examines the effect of ionizing radiation on cochlear implant function. The implanted devices examined were the Nucleus CI24M and Nucleus CI24R(CS). In a modeled study, two implants of each type were treated with fraction schemes most frequently used in clinical routine (e.g., conventional fractionation [total dose, 120 Gy] and hyperfractionation [total dose, 116 Gy]). Parameters quantified were the implant output amplitude changes at high and low current level (current levels 255 and 100, respectively), the charge balance of the biphasic pulse, and the accuracy of the impedance telemetry function. RESULTS: Within the clinically relevant dose range (< 80 Gy), implant function in all four devices was normal. Failure occurred in one Nucleus CI24R(CS) device treated with hyperfractionation. A dramatic drop in the output amplitude at 106 Gy was observed, and the impedance measurement failed at a total dose of 111 Gy. CONCLUSION: The results suggest that conventional or hyperfractionated radiotherapy can be applied safely at Nucleus CI24M or CI24R(CS) implant systems in a patient-like setting. Therefore, the authors propose that the results of the study can be applicable in clinical practice.

Cochlear Implants↗
PubMed2004

Cochlear implantation between 5 and 20 months of age: the onset of babbling and the audiologic outcome.

OBJECTIVE: The objective of this study was to investigate the onset of prelexical babbling and the audiologic outcome of 10 deaf children who received a cochlear implant (CI) before the age of 20 months. STUDY DESIGN: A prospective longitudinal observation and analysis. PATIENTS: Ten congenitally deaf infants implanted at an age between 6 and 18 months. INTERVENTION: All children received a Nucleus-24 multichannel cochlear implant. MAIN OUTCOME MEASURES: 1) The onset of babbling defined as a) the first appearance of multiple articulatory movements and b) a canonical babbling ratio of.2 or higher; 2) the babbling spurt defined as a sudden increase of babbled utterances; 3) the audiologic outcome defined by the CAP score (Categories of Auditory Performance) and the results of the A[S]E (Auditory Speech Sound Evaluation). RESULTS: All children started babbling after a short interval of 1 to 4 months after activation of the device so that the onset of babbling in the youngest subjects occurred at a chronologic age comparable to that of normally hearing infants. The outcomes of the different babbling measures correlated significantly with the age of implantation: the earlier the implantation, the closer the results approached the outcomes of normally hearing infants. The children implanted in their first year of life showed a normal CAP development as early as 3 months after implantation. All CI children were able to discriminate phoneme pairs of the A[S]E immediately after the fitting of the device. CONCLUSIONS: The earlier the implantation took place, the smaller the delay was in comparison with normally hearing children with regard to the onset of prelexical babbling and with regard to auditory performance as measured by CAP.

Age Factors↗
PubMed1997

Complications of cochlear implant surgery in children.

OBJECTIVE: To evaluate the intraoperative problems and postoperative complications in children receiving cochlear implants. STUDY DESIGN: A retrospective analysis of the clinical records of 366 children, aged 1 to 14 years, who had received cochlear implants. RESULTS: Intraoperatively, obliteration of the cochlea occurred in 66 patients, cochlear dysplasia in 8, and CSF leakage in 7, and nearly 5% of patients had signs of infection in the mucosa of the middle ear. Postoperatively, early complications occurred in 1% to 2.5% of patients: flap complications, electrode dislocation, facial nerve problems, and incorrect insertion of the electrode. Delayed complications included otitis media and stimulation of the facial nerve. CONCLUSION: Proper preparation of the implantation site, experienced and well-trained surgeons, and awareness of the operative and postoperative risks are necessary.

Adolescent↗
PubMed1996

Verbal information-processing capabilities and cochlear implants: implications for preoperative predictors of speech understanding.

In this study, we examined preoperative verbal cognitive capacity in 11 deafened adults who were cochlear implant candidates and reexamined level of speech understanding after 6-8 months' experience with the implant. Verbal cognitive performance in the implant group was compared in a group of normal hearing subjects and in nonimplanted group of deafened adults. The three groups performed on par with each other with an exception: The individuals in the cochlear implant group and the nonimplanted group of deafened adults performed significatly worse than those of normal hearing in tasks in which use of internal speech is a key feature (i.e., rhyme judgement and lexical decision tasks). Postoperative observations of the implanted individuals' level of speech understanding suggest that it is possible to predict the level of speech understanding by means of a properative cognitive assessment. The characteristics of three verbal cognitive abilities prove to be critical indicators of 6 - 8 months' postoperative outcome: internal speech functioning, speed of verval information processing, and working memory capacity - the first factor proved the most decisive. We discuss the results with respect to direct versus indirect predictors of outcomes from cochlear implant operations and the effect of auditory deprivation on deafened adults' capability to process auditory information.

Journal Article↗
PubMed1998

Cochlear implant performance and electrically-evoked auditory brain-stem response characteristics.

OBJECTIVES: The purpose of this study was to find a correlation between cochlear implant performances in phoneme discrimination and activity of the brain-stem. METHODS: Electrically-evoked auditory brain-stem responses (EABRs) and speech recognition performances were measured in 17 patients implanted with an MXM Digisonic DX10 cochlear implant. Speech recognition performances without lip-reading were tested using lists of isolated French words containing 3 phonemes. RESULTS: The results indicated statistically significant correlations between phoneme correct-identification scores and the following EABR variables: wave V latency, wave II-V latency interval and wave III-V latency interval. These results, indicate that up to about 48% of the variance in isolated word recognition without lip-reading can be accounted for by EABR variables. CONCLUSION: The quality of brain-stem functioning influences central processes in phoneme discrimination.

Adult↗
PubMed2002

Fetal central auditory system metabolic response to cochlear implant stimulation.

OBJECTIVES: The purpose of this study was to examine the effects of profound auditory deprivation and its treatment by cochlear implantation and stimulation on the metabolic activity of the central auditory system in fetal sheep. METHODS: Six ovine fetuses at 85% to 90% gestation were bilaterally deafened by kanamycin perfusion and unilaterally implanted with cochlear electrode arrays. Half of the implanted animals were stimulated with an extrauterine sound processor, and half were not. Four animals served as hearing controls. One week postoperatively, central nervous system metabolic activity was evaluated in ambient laboratory noise by quantitative autoradiography using (14)C-deoxyglucose. RESULTS: Kanamycin perfusion deafened all treated animals as verified by auditory brainstem response and scanning electron microscopy. Glucose utilization in the inferior colliculus was markedly lower in deafened and unstimulated animals relative to hearing controls. Glucose utilization in implanted-stimulated animals was similar to normal controls. CONCLUSIONS: Changes in central auditory system metabolic activity associated with congenital deafness may be minimized by prompt auditory habilitation.

Animals↗
PubMed2003

Usher syndrome and cochlear implantation.

OBJECTIVE: To evaluate the symptoms leading to diagnosis and the quality of rehabilitation after cochlear implantation in Usher syndrome. STUDY DESIGN: Retrospective cohort study. SETTING: ENT department of a tertiary referral hospital. PATIENTS: Among 210 patients given an implantation in the Ear, Nose, and Throat department, 185 were congenitally deaf and 13 had Usher syndrome (7.0%). Five had a family history of Usher, and eight were sporadic cases. Eleven cases were Usher type I, one was Usher type III, and one was not classified. The age at implantation ranged from 18 months to 44 years (mean, 6 years 1 month). The mean follow-up was 52 months (range, 9 months to 9 years). MAIN OUTCOME MEASURES: All patients had audiophonological and clinical examination, computed tomography scan of the temporal bones, ophthalmologic examination with fundoscopy, and an electroretinogram. Cerebral magnetic resonance imaging and vestibular examination were performed in 9 of 13 and 10 of 13 cases, respectively. Logopedic outcome measured preimplant and postimplant closed- and open-set word recognition and oral expression at follow-up. RESULTS: The most frequent initial sign of Usher syndrome was delayed walking, with a mean age of 20 months. Among the 172 other congenitally deaf children with implants, when deafness was not associated with other neurologic disorders, the mean age at walking was 14 months (p < 0.001). The fundoscopy was always abnormal after the age of 5 years, and the electroretinogram was abnormal in all cases. Vestibular function was abnormal in all but one case (nonclassified). The computed tomography scan and the magnetic resonance imaging were always normal. Logopedic results with cochlear implants showed good perception skills in all but one case. The best perceptive results were obtained in children implanted before the age of 9 years. Oral language had significantly progressed in 9 of 13 at follow-up. There was no relation between the visual acuity and the logopedic results. CONCLUSION: The earliest clinical sign associated with deafness evoking Usher syndrome is late walking. The electroretinogram is the only reliable examination to enable the diagnosis. When severe profound deafness is associated with late walking, the electroretinogram should be systematically proposed. Logopedic results are linked to precocity of implantation, and early Usher's diagnosis contributes to optimize speech therapy.

Age Factors↗
PubMed1998

The identification of consonants and vowels by cochlear implant patients using a 6-channel continuous interleaved sampling processor and by normal-hearing subjects using simulations of processors with two to nine channels.

OBJECTIVE: To compare the vowel and consonant identification ability of cochlear implant patients using a 6-channel continuous interleaved sampling (CIS) processor and of normal-hearing subjects using simulations of processors with two to nine channels. DESIGN: Subjects, 10 normal-hearing listeners and seven cochlear implant patients, were presented synthetic vowels in /bVt/ context, natural vowels produced by men, women, and girls in /hVd/ context, and consonants in /aCa/ context for identification. Stimuli for the normal-hearing subjects were pre-processed through simulations of implant processors with two to nine channels and were output as the sum of sinusoids at the center frequencies of the analysis filters. RESULTS: Five implant patients' scores fell within the range of normal performance with a 6-channel processor when the patients were tested with synthetic vowels. Four patients' scores fell within the range of normal with a 6-channel processor when the patients were tested with multitalker vowels. Five patients' scores fell within the range of normal for a 6-channel processor for the consonant feature "place of articulation." CONCLUSION: Signal processing technology for cochlear implants has matured sufficiently to allow some patients who use CIS processors and a small number of monopolar electrodes to achieve scores on tests of speech identification that are within the range of scores established by normal-hearing subjects listening to speech processed through a small number of channels.

Adult↗
PubMed1986

Speech therapy with cochlear implant wearers.

The speech production of three post-lingually deafened adults, who derived no benefit from wearing hearing aids, was assessed. Individual therapy programmes were devised based on these assessments and the subjects participated in a course of speech therapy. They then received cochlear implants and had a further course of speech therapy using their implants. Changes in speech production were judged by trained listeners, who heard tape-recorded samples of the subjects' speech. These samples were taken at various intervals before and after therapy alone, and with the cochlear implant. Significant improvement was heard in the speech production of two of the subjects following speech therapy alone. All three subjects were judged to have improved production of speech after using their cochlear implants for 6 months.

Cochlear Implants↗
PubMed1995

Cortical activation with sound stimulation in cochlear implant users demonstrated by positron emission tomography.

Six postlingually deaf patients using multi-channel cochlear implants were examined by positron emission tomography (PET) using 15O-labeled water. Changes in regional cerebral blood flow (rCBF) were measured during different sound stimuli. The stimulation paradigms employed consisted of two sets of three different conditions; (1) no sound stimulation with the speech processor of the cochlear implant system switched off, (2) hearing white noise and (3) hearing sequential Japanese sentences. In the primary auditory area, the mean rCBF increase during noise stimulation was significantly greater on the side contralateral to the implant than on the ipsilateral side. Speech stimulation caused significantly greater rCBF increase compared with noise stimulation in the left immediate auditory association area (P < 0.01), the bilateral auditory association areas (P < 0.01), the posterior part of the bilateral inferior frontal gyri; the Broca's area (P < 0.01) and its right hemisphere homologue (P < 0.05). Activation of cortices related to verbal and non-verbal sound recognition was clearly demonstrated in the current subjects probably because complete silence was attained in the control condition.

Acoustic Stimulation↗
PubMed2004

Event-related potentials in pediatric cochlear implant patients.

OBJECTIVE: The main objective of this study was to assess the correlation of auditory event related potential (ERP) measures with behavioral assessment data to identify if ERPs including mismatch negativity (MMN) can be used to categorize cochlear implant patients into good and poor performers. DESIGN: We investigated auditory event-related potentials to standard and deviant speech stimuli presented in a pseudorandom sequence in 35 cochlear implant patients between the ages of 7 and 17 yr. We compared the occurrence, latencies, and amplitudes of P1, N2, and MMN with overall behavioral outcome in these children. Behavioral measures included category of auditory performance scores and speech intelligibility rating scores. RESULTS: Auditory ERPs in response to standard stimuli were identifiable in 30 of 35 patients, demonstrating a major positive component (P1) followed by a negativity (N2) with absence of N1 in all patients. The P1 component in prelingually deaf patients showed a statistically significant reduction in its latency with increasing duration of implant use. MMN was recorded in 80-85% of star performers but in only 15-20% of poor performers. Patients with higher SIR scores demonstrated statistically significant longer duration of MMN compared with those with a lower SIR score. CONCLUSIONS: These results indicate that MMN can be used to assess the functional status of the auditory cortex in terms of auditory memory and discrimination in young children with cochlear implants and may provide an objective mechanism for differentiating good from poor performers.

Adolescent↗
PubMed1996

[Ionomer cement in cochlear implant surgery--applications and long-term outcome].

Over the last ten years about 850 cochlear implant operations were performed at the ENT department of Hannover Medizinische Hochschule. In most cases, intracochlear nucleus implants were used. For about two years the intracochlear Clarion device has also been used in 150 adults and children. For several years we have used ionomeric cement (lonocap, supplied by lonos, Seefeld/Germany) to fix the electrode array in the region of the posterior wall and the facial recess. Previously, the implant package was fixed by ionomeric cement. To evaluate the outcome of cement application, we conducted a prospective study of our implant patients during the period from 1991 to 1993. During regular reexamination over a period of two years postoperatively in 244 patients (122 male and 122 female patients, average age 17.6 years), we did not observe any complication related to the cement. Nearly all revision cases (n = 8) showed a stable contact between electrode array, bone, and cement. With increasing experience, we reduced the cement application and fixed the package with vicryl sutures in a precisely drilled bony bed. Contact of the cement with neural and cerebral structures should be avoided. In our experience ionomeric cement is a helpful tool in cochlear implant surgery with long-term stability and no rejection reactions.

Adolescent↗
PubMed2000

Differential recruitment of the speech processing system in healthy subjects and rehabilitated cochlear implant patients.

Differences in cerebral activation between control subjects and post-lingually deaf rehabilitated cochlear implant patients were identified with PET under various speech conditions of different linguistic complexity. Despite almost similar performance in patients and controls, different brain activation patterns were elicited. In patients, an attentional network including prefrontal and parietal modality-aspecific attentional regions and subcortical auditory regions was over-activated irrespective of the nature of the speech stimuli and during expectancy of speech stimuli. A left temporoparietal semantic region was responsive to meaningless stimuli (vowels). In response to meaningful stimuli (words, sentences, story), left middle and inferior temporal semantic regions and posterior superior temporal phonological regions were under-activated in patients, whereas anterior superior temporal phonological regions were over-activated. These differences in the recruitment of the speech comprehension system reflect the alternative neural strategies that permit speech comprehension after cochlear implantation.

Acoustic Stimulation↗
PubMed2005

Cochlear implantation in children younger than 12 months.

OBJECTIVES: As a result of universal newborn hearing screening and improved evaluation tools, many children with severe to profound hearing loss are being diagnosed as infants. This affords the opportunity to provide these children access to cochlear implantation, although medical and audiologic challenges must be addressed. The purpose of this study was to investigate the safety and efficacy of cochlear implantation in children who are younger than 1 year. METHODS: A prospective study was conducted of 18 children who had confirmed severe to profound sensorineural hearing loss and received cochlear implants at our medical center before 12 months of age. The length of device usage ranged from 6 months to 4 years, 5 months. The main outcomes measured were perioperative and postoperative surgical/medical aspects, the Infant-Toddler Meaningful Auditory Integration Scale and age-appropriate phoneme, and word and sentence recognition tests, when appropriate. RESULTS: All children had full insertions of the electrode array without surgical complications and are developing age-appropriate auditory perception and oral language skills. CONCLUSIONS: Early implantation is feasible and beneficial in some children who are younger than 12 months and should be considered with attention to variables involved in the decision-making process, including possible increased surgical risk, skull size and scalp thickness, and mastoid development.

Auditory Threshold↗
PubMed1993

Insertional trauma of multichannel cochlear implants.

Insertional trauma to the cochlea from three different multichannel cochlear implant electrodes was evaluated in a single-blind controlled study in fresh human temporal bones. Sixteen fresh human temporal bones were implanted with one of three types of multichannel electrodes (Symbion/InnerAid, Cochlear/Nucleus, or Storz/UCSF). Seven temporal bones were used as controls where a cochleostomy only was created. The temporal bones were evaluated histologically and cochlear histograms of the trauma were created. Although the three electrode designs caused damage which was unlikely to hinder implant performance, a distinct pattern of trauma was seen with each of the three electrode types. The least traumatic of the three electrode designs in this study was the Nucleus type. The degree of insertional trauma may be relevant to changing indications for insertion of cochlear implants as well as for patients with device failure who require reimplantation.

Basilar Membrane↗
PubMed1991

Melodic, rhythmic, and timbral perception of adult cochlear implant users.

The purpose of this pilot study was to investigate adult Ineraid and Nucleus cochlear implant (CI) users' perceptual accuracy for melodic and rhythmic patterns, and quality ratings for different musical instruments. Subjects were 18 postlingually deafened adults with CI experience. Evaluative measures included the Primary Measures of Music Audiation (PMMA) and a Musical Instrument Quality Rating. Performance scores on the PMMA were correlated with speech perception measures, music background, and subject characteristics. Results demonstrated a broad range of perceptual accuracy and quality ratings across subjects. On these measures, performance for temporal contrasts was better than for melodic contrasts independent of CI device. Trends in the patterns of correlations between speech and music perception suggest that particular structural elements of music are differentially accessible to cochlear implant users. Additionally, notable qualitative differences for ratings of musical instruments were observed between Nucleus and Ineraid users.

Adult↗
PubMed2005

Auditory cortical activation and speech perception in cochlear implant users: effects of implant experience and duration of deafness.

This study aimed to investigate the relationship between outcome following cochlear implantation and auditory cortical activation. It also studied the effects of length of implant use and duration of deafness on the auditory cortical activations. Cortical activity resulting from auditory stimulation was measured using [(18)F]FDG positron emission tomography. In a group of 18 experienced adult cochlear implant users, we found a positive correlation between speech perception and activations in both the primary and association auditory cortices. This correlation was present in a subgroup of experienced implant users but absent in a group of new implant users with similar speech perception abilities. There was a significant negative correlation between duration of deafness and auditory cortical activation. This study gives insights into the relationship between implant speech perception and auditory cortical activation and the influence of duration of preceding deafness and implant experience.

Acoustic Stimulation↗