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PubMed2002

Movements of cochlear implant electrodes inside the cochlea during insertion: an x-ray microscopy study.

BACKGROUND: There are no satisfactory, noninvasive techniques currently available to visualize the cochlear implant (CI) electrode in a dynamic state as it is advanced inside the cochlea. OBJECTIVE: This study describes a radiologic technique that can be used in temporal bones to monitor the electrode position in real time and to visualize the basilar membrane. METHODS: A cochleostomy was performed in accordance with the normal procedure for cochlear implantation in seven fresh cadaveric temporal bones. A special x-ray tube (Microfocus; Focus, Wunstorf, Germany) with a spot size of 1 microm and fluoroscopy were used for continuous videotape imaging of the advancing electrode in the cochlea. Conventional electrodes (MED-EL 40+; MED-EL, Innsbruck, Austria) and prototypes of perimodiolar electrodes (MED-EL), with varying thicknesses and angles of insertion, were used for the study. Finally, contrast liquid (Ultravist; Berlex Imaging, Schering, Germany) was injected into the scala vestibuli through the stapes footplate. RESULTS: The advancing electrode carrier was clearly visible at x20 magnification. With the perimodiolar electrodes, deep insertion was impossible if the guiding wire was too rigid, and retraction occurred if the wire was soft. The intact nature of the basilar membrane could be confirmed by the sequential filling of scala vestibuli and the scala tympani. CONCLUSION: To our knowledge, this is the first noninvasive study demonstrating continuous visualization with high-resolution and x-ray magnification of CI electrode advancement inside the intact cochlea. Our technique can be used for the development of CI electrodes with optimal design characteristics, especially stiffness. Visualization of the basilar membrane will influence the insertion techniques when CIs are developed for patients with residual hearing.

Basilar Membrane↗

PubMed1998

Timbral recognition and appraisal by adult cochlear implant users and normal-hearing adults.

The purpose of this study was to examine the appraisal and recognition of timbre (four different musical instruments) by recipients of Clarion cochlear implants (CIS strategy, 75- or 150-microsec pulse widths) and to compare their performance with that of normal-hearing listeners. Twenty-eight Clarion cochlear implant users and 41 normal-hearing listeners were asked to give a subjective assessment of the pleasantness of each instrument using a visual analog scale with anchors of "like very much" to "dislike very much," and to match each sound with a picture of the instrument they believed had produced it. No significant differences were found between the two different pulse widths for either appreciation or recognition; thus, data from the two pulse widths following 12 months of Clarion implant use were collapsed for further analyses. Significant differences in appraisal were found between normal-hearing listeners and implant recipients for two of the four instruments sampled. Normal-hearing adults were able to recognize all of the instruments with significantly greater accuracy than implant recipients. Performance on timbre perception tasks was correlated with speech perception and cognitive tasks.

Adult↗

PubMed1989

The narrow internal auditory canal in children: a contraindication to cochlear implants.

We suggest a new explanation for the lack of auditory response to electric stimulation in children with cochlear implants: the very narrow internal auditory canal, 1 to 2 mm in diameter, and the probable absence of the cochlear nerve. This defect can be seen on high-resolution computed tomographic x-ray studies and may represent aplasia of the auditory-vestibular nerve. We report on eight children with this anomaly, three of whom have received implants and failed to respond with a sensation of sound. Identification of this problem on screening x-ray films is a contraindication to cochlear implantation for auditory stimulation.

Acoustic Stimulation↗

PubMed2002

Minimal access surgery for pediatric cochlear implantation.

OBJECTIVE: To develop a minimal access approach for pediatric cochlear implantation to improve the acceptability of the procedure for parents, children, and the wider community, and to reduce flap-related complications of the procedure. STUDY DESIGN: Prospective evaluation of a new surgical technique. METHOD: A new approach was developed through a short, oblique, straight postauricular incision without shaving any hair. It involved drilling the bony well for the implant inside a small subperiosteal pocket. PATIENTS: Twenty-three consecutively implanted children with the Nucleus implanted system, whose median age was 3.2 years (mean 4.1 years, range 1.6-11.2 years. RESULTS: The technique proved feasible in all the 23 children, and no major complications were encountered. Three instances of wound edema were observed early in the series; by minimizing tissue elevation and overzealous retraction, these complications were not encountered subsequently. The approach was warmly endorsed by parents, children, and caregivers, who greatly appreciated the minimal impact of the approach. CONCLUSION: The proposed new approach is very well accepted by implanted children and their families, reduces the psychologic trauma of the intervention, and has less risks of flap complications.

Child↗

PubMed1988

Multichannel cochlear implantation in a patient with bilateral Mondini deformities.

A 31-year-old man with bilateral Mondini dysplasia was successfully implanted with a Nucleus multichannel 22-electrode cochlear prosthesis. To our knowledge, this is the first report of multichannel cochlear implantation in a patient with Mondini dysplasia. The surgical procedure used to insert the device was uncomplicated. Although objective measurements demonstrated only slight improvement in most categories of the Iowa test battery, he has the ability to discriminate pure-tone frequency differences and environmental sounds. Subjectively, he was a satisfied implant user. The surgical feasibility of multichannel implantation in patients with Mondini dysplasia should open the door for improved speech recognition and tonal discrimination in this subset of patients.

Adult↗

PubMed1992

Management of flap necrosis in cochlear implantation.

Skin flap complications are the most commonly reported problems in cochlear implant surgery when the anteriorly based C-shaped flap is used for the incision. If the prosthesis is exposed by flap necrosis, local skin flaps may be used to obtain coverage. Unfortunately, the long-term viability of such flaps may be compromised by the pressure exerted by the transmitter. Two cases of flap necrosis severe enough to expose the prosthesis have been successfully managed by relocating the device to a position superior to the auricle, under healthy skin. In one case the receiver was removed owing to infection and reimplanted at a later date. In this case, the electrode array was left in place at explantation in order to stent the cochlea. The surgical techniques and flap designs for this procedure are presented. No further surgical complications have developed in either case. The devices are performing well for both patients at this time. We have found relocation of the implant a useful technique in the management of major flap necrosis. This technique may also be useful to prevent flap necrosis should excessive flap thinning occur during the implant operation.

Adult↗

PubMed2006

Revision cochlear implantation for facial nerve stimulation in otosclerosis.

OBJECTIVE: To find if patients experiencing postsurgical facial nerve stimulation caused by underlying disease process (ie, otosclerosis) can improve their hearing performance with their cochlear implant by reimplantation and by an optimal programming strategy. DESIGN: Retrospective analysis. SETTING: Academic tertiary referral center. PATIENTS: Two cochlear otosclerosis patients with resistant facial nerve stimulation (FNS). Both patients were initially implanted with Nucleus 22 devices (Cochlear Corporation, Englewood, Colo) and they developed FNS after a period of use. Owing to the decreasing number of active electrodes, concurrent decreases in speech understanding occurred. INTERVENTIONS: Various programming approaches were used to address the FNS. Both subjects ultimately received Nucleus 24 devices. One was reimplanted in the same ear, and the other was implanted in the opposite ear. Both have been followed up for 8 months following the reimplantation. MAIN OUTCOME MEASURES: Cochlear implant programming levels, cochlear implant performance, and facial nerve stimulation. RESULTS: The FNS was managed for more than 3 years through optimized programming. However, the FNS progressed until performance dropped below acceptable levels. Reimplantation was believed to be the only option for improvement. After reimplantation and programming, both subjects showed immediate improvement in speech discrimination. One user increased his consonant-nucleus-consonant word score from 12% preoperatively to 42%, and the other's performance increased from 0% to 86%. CONCLUSIONS: Our results suggest that having more programming options with newer devices is critical in otosclerotic or ossified users who experience FNS. Also, reimplantation may be a useful tool to improve performance.

Cochlear Implantation↗

PubMed1996

Electric response audiometry in young children before cochlear implantation: a short latency component.

OBJECTIVE: Evaluation of a short latency component (SLC) observed in profoundly deaf young children during recordings of the auditory brain stem response (ABR) before cochlear implantation. DESIGN: Seventy young children (ages 2 to 11 yr) were investigated as part of their routine audiologic and diagnostic assessment, before cochlear implantation. The ABR was evoked using click stimuli and tone pips (500 Hz and 1 kHz) at intensity levels up to 105 dB nHL. The incidence of the SLC arising at a latency of 3 msec with high level click stimuli, in addition to residual ABR waves, was assessed. RESULTS: An SLC was observed in a total of 18 of the 70 children investigated. It was present in 15 out of 31 congenitally deaf children (48%) compared with only 2 out of 33 children deafened after meningitis (6%). A chi-squared test employing a 2 x 2 contingency table shows that this dependency on etiology of deafness is highly statistically significant (p < 0.001). The presence of the SLC in the congenitally deaf children is related to age at the time of the Electric Response Audiometry test and is more likely to be observed in the younger child (p < 0.01). CONCLUSIONS: Interpretation of the ABR in profoundly deaf children should take into consideration the possible presence of the SLC. An evoked potential arising from stimulation of the vestibular system, particularly the vestibular nuclei, is proposed as a likely origin for this component. Damage to sensory cells in the vestibular portion of the labyrinth might explain why an SLC is seen rarely in cases of deafness after meningitis.

Artifacts↗

PubMedDate not supplied

Histologic evaluation of temporal bones with cochlear implants.

Ectopic bone in the scala tympani is characteristic of cochlear otosclerosis and meningitis, which are the two most frequent etiologies of deafness in cochlear implant patients. The ectopic bone in a multiple-electrode implanted bone is probably caused by disease (syphilis) rather than by the electrode or electrical stimulation. The sensory elements being stimulated by intracochlear electrodes probably are the ganglion cells.

Cochlear Implants↗

PubMed2006

Quality of life and cochlear implantation in Usher syndrome type I.

OBJECTIVES: The objectives of this descriptive, retrospective study were to evaluate quality of life, hearing, and vision in patients with Usher syndrome type I with and without cochlear implant. METHODS: Quality of life (QoL) of 14 patients with Usher type I (USH1) with a cochlear implant (CI) (seven adults, seven children) was compared with those of 14 patients with USH1 without a CI (12 adults, two children) by means of three questionnaires: NCIQ, SF12, and the Usher Lifestyle Survey. Additional information on hearing level was obtained by the equivalent hearing loss (EHL) principle and on the visual deterioration by the functional vision score (FVS). RESULTS: A significant benefit of CI was seen in the hearing-specific questionnaire NCIQ. This difference could not be detected in the generic SF12 survey. The Usher Lifestyle Survey indicated that patients with USH1 with a CI tend to be able to live an independent life more easily than the profoundly deaf unimplanted patients with USH1. EHL and FVS scores varied in both groups. CONCLUSIONS: Overall QoL can be enhanced by CI in patients with USH1, although effects are mostly seen in hearing-related QoL items.

Adolescent↗

PubMed1995

Cochlear implant extrusion in a young child--a preventive procedure.

A Cochlear Mini System 22 Channel cochlear implant extruded through the skin of a young girl. The implant was saved by use of a transposition flap. Extrusion appeared to be due to pressure necrosis from the implant on the overlying tissues. It is believed that this problem can be prevented by angulation of the implant before insertion so that it conforms to the curvature of the skull, so avoiding pressure on the tissues. The method of angulation is described.

Child, Preschool↗

PubMed1980

Labyrinthine ossificans and cochlear implants.

We report two clinical and five histopathological examples of labyrinthitis ossificans and discuss the possible cause of this condition. Diagnosis can be established by polytomography. The advent of the cochlear implant makes ossification of the cochlea (labyrinthitis ossificans) of more than academic interest, since it requires alteration of the insertion of an electrode into the scala tympani and minimizes the chances of successful stimulation. Hearing losses due to meningitis, advanced cochlear otosclerosis, and trauma are likely to be due to cochlear ossification. Therefore, it is important to rule out this condition by means of polytomography in individuals being considered for cochlear implant surgery.

Adult↗

PubMed1999

Depth and quality of electrode insertion: a radiologic and pitch scaling assessment of two cochlear implant systems.

OBJECTIVE: To compare the depth of electrode insertion in two types of cochlear implants, and to assess the ability of the implantees in each group to place-pitch during random electrical stimulation. STUDY DESIGN: This was a prospective clinical study. SETTING: This study was performed at an implant program within a university teaching hospital. PATIENTS: Five consecutive patients with the Clarion (Advanced Bionics, Symlar, CA, U.S.A.) device and 5 with the Nucleus-22 (Cochlear Corporation, Sydney, Australia) implants were enrolled. All 10 implantees had fully active and functioning electrodes. INTERVENTIONS: The depth of insertion was determined using plain anteroposterior skull film and high resolution computed tomography (CT). The quality of electrode insertion was assessed by pitch scaling; electrodes were randomly stimulated to generate subjective pitch responses. OUTCOME MEASURES: The depth of electrode insertion was measured radiographically as degrees of angular rotation within the cochlea. For pitch scaling, the averaged responses to electrical stimulation was plotted against the "place" of the electrodes along the array. Pitch range, plateauing, and reversal of pitches were also noted. Insertion depth was correlated with the result of pitch scaling and open-set speech discrimination at 3 months. RESULTS: The mean insertion depth was 406 degrees for the Clarion device and 254 degrees for the Nucleus device. CT was used to confirm the intracochlear placement of the electrodes and their relationships to the cochleostomy site. It did not confer more information than the plain films unless kinking had occurred. Pitch perception was consistent with the tonotopic organization of the cochlea. The Nucleus-22 recipients displayed a broader range of pitches with less plateaus and reversals than the Clarion implants. The depth of insertion did not compare well with the outcome of pitch scaling or with open-set speech discrimination scores in either group of implantees. CONCLUSION: The preformed spiral array of the Clarion device allowed deeper electrode insertion compared to the Nucleus-22 device. However, depth of insertion did not translate into better pitch placement.

Adult↗

PubMed1994

Programming the cochlear implant based on electrical acoustic reflex thresholds: patient performance.

The electrical acoustic reflex threshold (EART) has been shown to be a reliable estimate of behavioral comfort levels in both child and adult cochlear implant patients. The purpose of this study was to investigate the potential for using EARTs for programming the Nucleus cochlear implant. EARTs and behavioral comfort levels were obtained from 7 adult implant patients. Two programs or "maps" were made for each patient, one based on behavioral comfort levels and one based on EARTs. Performance on open set tests of speech recognition was measured with each map. Mean data suggest that speech perception is similar with both maps. Analysis of individual data revealed that, whereas 2 subjects performed better with the C-level maps, the remaining 5 subjects tended to perform either better with the EART map or equally well with both maps. These results suggest that EARTs may be an adequate substitute for comfort levels when programming the implant for patients who are unable to make reliable psychophysical judgments.

Adult↗

PubMed1994

Temporal bone imaging for cochlear implantation.

Computerized tomography (CT) imaging of the inner ear structures is helpful when evaluating a patient for cochlear implantation. The accuracy of CT scan imaging in determining the presence of cochlear ossification was assessed. A retrospective study of 104 implant patient charts, operative reports, and CT scans was performed. The CT scan was in agreement with the operative findings in 78% of patients included in the study. Twenty-two percent were found to have ossification at surgery which was not detected radiographically. One patient with extensive otospongiosis and an obstructed cochlea on CT scan had a patent cochlea demonstrated by magnetic resonance imaging (MRI) which was corroborated at surgery. In 32 children with postmeningitic hearing loss, the CT scan had only a 53% accuracy in assessing cochlear ossification. Since 69% of these patients were found to have some degree of cochlear ossification, otologists should expect to encounter some degree of bony obstruction within the basal turn of the cochlea even when the CT scan is normal. Nevertheless, cochlear implantation can successfully be performed in these cases.

Adolescent↗

PubMed1999

Cochlear implantation of a deaf blind patient with mitochondrial cytopathy.

Genetic defects of the mitochondrial DNA often cause sensorineural hearing impairment, accompaniment by disorders of organs within the body. This case report describes cochlear implantation of a 33-year-old deaf blind female with mitochondrial cytopathy. The outcome was very successful, and vastly improved quality of life for this patient. Many cases of mitochondrial cytopathy cause progressive deafness; it is, therefore, likely that other patients with this unusual disorder will present for cochlear implant assessment.

Adult↗

PubMed1988

Vibrotactile device in patients with single-channel cochlear implant: a preliminary study.

Two patients who had been using 3-M Vienna extracochlear implants were given two-channel KS Sensoraid vibrotactile units to wear for 1 month. At the end of that period, several tests commonly used to assess cochlear implant function were administered to compare the effectiveness of the vibrotactile system with that of the cochlear implants. The results obtained from the vibrotactile devices were encouraging, although the units had some shortcomings. Overall, the subjects' test scores with the vibrotactile units were comparable to, if not slightly better than, those with the extracochlear implants.

Adult↗

PubMed2006

Does cause of deafness influence outcome after cochlear implantation in children?

OBJECTIVES: The objective of this study was to evaluate long-term speech perception abilities of comparable groups of postmeningitic and congenitally deaf children after cochlear implantation. METHODS: This prospective longitudinal study comprised 46 postmeningitic deaf children and 83 congenitally deaf children with age at implantation of < or = 5.6 years. Both groups were comparable with respect to educational setting and mode of communication and included children with additional disabilities. RESULTS: Both postmeningitic and congenitally deaf children showed significant progress after implantation. Most (73% and 77%, respectively) could understand conversation without lip-reading or use the telephone with a known speaker 5 years after implantation, whereas none could do so before implantation. At the same interval, the postmeningitic and congenitally deaf children scored a mean open-set speech perception score of 47 (range: 0-91) and 46 (range: 0-107) words per minute, respectively, on connected discourse tracking. The respective mean scores at the 3-year interval were 22 and 29 correct words per minute, respectively. None of these children could score a single correct word per minute before implantation. The progress in both groups was statistically significant. When the 2 groups were compared, there was no statistically significant difference. CONCLUSION: Postmeningitic and congenitally deaf children showed significant improvement in their auditory receptive abilities at the 3- and 5-year intervals after cochlear implantation. There was no statistically significant difference between the outcomes of the 2 groups, suggesting that, provided that children receive an implant early, cause of deafness has little influence on outcome. Although the prevalence of other disabilities was similar in both groups, for individual children, their presence may have profound impact. The study supports the concept of implantation early in life, irrespective of the cause of deafness.

Child↗

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