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PubMed2006

Prevalence of cochlear implants in postlingually deafened adults in a Swedish region.

Cochlear implantation (CI) rates vary between countries, depending on identification routines and economic restrictions. The present study aimed at determining the prevalence of CIs in postlingually deafened, aged 20-69 years old, in Göteborg, Sweden. Three patient databases with information on PTA, a questionnaire, medical records and consultations identified 88 subjects with sensorineural hearing loss >/=80 dB HL (PTA of 500, 1000, 3000 Hz), PB word score of </=30% (better ear), regular use of hearing-aid, and oral language. The prevalence of CIs was 11.8 per 100 000 population, and of subjects fulfilling the audiometric candidacy criteria 18.6 per 100 000. The mean PTA (op. ear) of subjects awaiting operation was 97 dB HL (SD 12.3), and of already implanted subjects 106 dB HL (SD 10.2). Mean PB word score was 9% (SD 8.9) and 3% (SD 4.9) respectively. Subjects awaiting operation had significantly better residual hearing, emphasizing recent changes in candidacy criteria. Comparing with prevalence from other countries demonstrated that more patients could be candidates for cochlear implantation.

Adult↗

PubMed1996

Improved and simplified methods for specifying positions of the electrode bands of a cochlear implant array.

OBJECTIVE: To develop techniques for measuring the positions of the individual electrodes of a multiple channel cochlear implant and for estimating associated characteristic frequencies. BACKGROUND: Information concerning the positions of the individual electrodes of a cochlear implant array is important for analyzing speech perception or psychophysical data and for optimizing speech-processing strategies. This study presents two techniques for obtaining such information from postoperative plain film radiographs. METHODS: A template spiral shape, derived from analysis of the radiographs of 30 cochlear implant patients, is used to obtain measurements of the angular positions of the electrode bands within scala tympani. A research technique measures angular positions and estimates characteristic frequencies for all electrode bands but requires that the positions of two cochlear landmarks and all electrode bands be digitized. A clinical technique provides similar angle and frequency estimates but requires a minimum of information to be extracted visually from the radiograph. The lateral positions of the bands are estimated, in the research technique, using mean outer and inner wall functions obtained from 11 Silastic molds of scala tympani. RESULTS: The mean position of the implanted array relative to the mean scala tympani outer wall function was consistent with published histologic observations of implanted temporal bones. Measured angles did not vary greatly with experimenter or with rotation of the cochlea relative to the radiographic beam by up to 20 degrees. CONCLUSIONS: The techniques described allow, principally, measurement of the longitudinal positions of the bands of a cochlear implant in scala tympani and estimation of corresponding characteristic frequencies.

Cochlea↗

PubMed1990

Computer-aided three-dimensional reconstruction and measurement for multiple-electrode cochlear implant.

To assist surgeons in performing multiple-electrode cochlear implant operations, the spatial relations between middle and inner ear structures in six normal temporal bones were studied using the computer-aided 3-D reconstruction method. When viewed through the external auditory canal, the approach used for electrode insertion, and the relation of the malleus to the helicotrema or the scala vestibuli in the second turn of the cochlea were found to vary considerably. In contrast, when viewed from the same transmeatal approach, both the direction and the distance from the stapes footplate to the scala vestibuli of the second turn of the cochlea and helicotrema were found to be quite stable. We concluded that the stapes footplate was a better landmark than the malleus when approaching the helicotrema and scala vestibuli of the second turn of the cochlea during multiple-electrode cochlear implant surgery.

Adolescent↗

PubMed1998

The effects of processor strategy on the speech perception performance of pediatric nucleus multichannel cochlear implant users.

OBJECTIVE: The present investigation examined the speech perception skills of pediatric cochlear implant users who changed from their original speech processors and strategies to the Spectral Peak (SPEAK) strategy. DESIGN: A within-subjects design was used to compare individual subject's performance using the SPEAK strategy with that obtained with their previous speech strategy (FOF1F2 or Multipeak) in this retrospective study. The subjects demonstrated a wide range of perceptual abilities and had used a cochlear implant for varying lengths of time before converting to the SPEAK strategy. RESULTS: Nine of the 11 subjects showed significant improvement on at least one of the open-set word recognition measures, whereas two subjects showed no change on any of the open-set measures when using the SPEAK strategy. CONCLUSIONS: The present results suggest that the majority of pediatric cochlear implant users are likely to show improved speech perception performance when converting to the new SPEAK processing strategy.

Audiometry, Pure-Tone↗

PubMed1998

Vowel perception in prelingually deafened children with multichannel cochlear implants.

Vowel perception ability for 16 prelingually deafened children using Nucleus 22-channel cochlear implants was studied at 12, 24, and 36 months postimplantation. Information transmission analysis was used to evaluate the effectiveness of the implants in conveying the essential cues required for accurate vowel identification and whether the cues used varied with experience or device use. Individual vowel identification varied widely with mean scores significantly improving between 12 and 24 months but not between 24 and 36 months. Information transmission scores for all vowel features (fronting, height, duration, and diphthongization) increased dramatically between 12 and 36 months. Results indicated that vowel height and vowel fronting were the most salient features for the subject group. There were no differences in the pattern of confusions made across test sessions or across groups when divided into "poor" and "good" users. However, there was evidence that the "good" users made better use of higher frequency formant information than the "poor" users. The results of the present study add to the accumulation of evidence pointing to the great benefit that cochlear implantation can provide to prelingually deafened children. Overall performance for the vowel recognition test used in this study was quite high and analysis of the childrens' errors suggested that their cochlear implants were reasonably effective at conveying the most essential spectral information required for vowel discrimination.

Age Factors↗

PubMed2005

Improved speech perception in adult congenitally deafened cochlear implant recipients.

OBJECTIVE: To determine whether congenitally deafened adults achieve improved speech perception when auditory and visual speech information is available after cochlear implantation. STUDY DESIGN: Repeated-measures single subject analysis of speech perception in visual-alone, auditory-alone, and audiovisual conditions. SETTING: Neurotologic private practice and research institute. SUBJECTS: Eight subjects with profound congenital bilateral hearing loss who underwent cochlear implantation as adults (aged 18-55 years) between 1995 and 2002 and had at least 1 year of experience with the implant. MAIN OUTCOME MEASURES: Auditory, visual, and audiovisual speech perception. RESULTS: The median for speech perception scores were as follows: visual-alone, 25.9% (range, 12.7-58.1%); auditory-alone, 5.2% (range, 0-49.4%); and audiovisual, 50.7% (range, 16.5-90.8%). Seven of eight subjects did as well or better in the audiovisual condition than in either auditory-alone or visual-alone conditions alone. Three subjects had audiovisual scores greater than what would be expected from a simple additive effect of the information from the auditory-alone and visual-alone conditions alone, suggesting a superadditive effect of the combination of auditory-alone and visual-alone information. Three subjects had a simple additive effect of speech perception in the audiovisual condition. CONCLUSION: Some congenitally deafened subjects who undergo implantation as adults have significant gains in speech perception when auditory information from a cochlear implant and visual information by lipreading is available. This study shows that some congenitally deafened adults are able to integrate auditory information provided by the cochlear implant (despite the lack of auditory speech experience before implantation) with visual speech information.

Adult↗

PubMedDate not supplied

Surgical strategy of cochlear implantation in patients with chronic middle ear disease.

We report 10 postlingually deafened adults in whom the electrophysical criteria for cochlear implant were fulfilled, except that they showed the following unfavorable middle ear lesions: otitis media with effusion, chronic perforative otitis media, cholesteatoma and previous radical ear operation. Staged operations for cochlear implant were performed in 8 cases, and 2 patients who had undergone radical ear operation had a single-stage operation. As a first step, one of the following was performed in each patient as surgically indicated: myringoplasty with or without mastoidectomy, mastoidectomy with reconstruction of the posterior wall of the external canal, mastoidectomy with the insertion of a ventilation tube, radical mastoidectomy or surgical cleansing of the radical cavity. From 6 months to 2.5 years after the first operation, the actual cochlear implant was performed in the second or third stage. There was no major complication as a result of electrode insertion into the cochlea and the results of speech perception in these cases were not different from those in patients with normal middle ears. In our experience, it was considered that the staged operations would enable successful cochlear implants in selected patients with pathological middle ear lesions even if they had previously been diagnosed as contraindicated for this procedure. In a case with radical ear cavity a single-stage operation could be performed when there was no cavity problem.

Adolescent↗

PubMed2006

Acoustic to electric pitch comparisons in cochlear implant subjects with residual hearing.

The aim of this study was to assess the frequency-position function resulting from electric stimulation of electrodes in cochlear implant subjects with significant residual hearing in their nonimplanted ear. Six cochlear implant users compared the pitch of the auditory sensation produced by stimulation of an intracochlear electrode to the pitch of acoustic pure tones presented to their contralateral nonimplanted ear. Subjects were implanted with different Clarion electrode arrays, designed to lie close to the inner wall of the cochlea. High-resolution radiographs were used to determine the electrode positions in the cochlea. Four out of six subjects presented electrode insertions deeper than 450 degrees . We used a two-interval (one acoustic, one electric), two-alternative forced choice protocol (2I-2AFC), asking the subject to indicate which stimulus sounded the highest in pitch. Pure tones were used as acoustic stimuli. Electric stimuli consisted of trains of biphasic pulses presented at relatively high rates [higher than 700 pulses per second (pps)]. First, all electric stimuli were balanced in loudness across electrodes. Second, acoustic pure tones, chosen to approximate roughly the pitch sensation produced by each electrode, were balanced in loudness to electric stimuli. When electrode insertion lengths were used to describe electrode positions, the pitch sensations produced by electric stimulation were found to be more than two octaves lower than predicted by Greenwood's frequency-position function. When insertion angles were used to describe electrode positions, the pitch sensations were found about one octave lower than the frequency-position function of a normal ear. The difference found between both descriptions is because of the fact that these electrode arrays were designed to lie close to the modiolus. As a consequence, the site of excitation produced at the level of the organ of Corti corresponds to a longer length than the electrode insertion length, which is used in Greenwood's function. Although exact measurements of the round window position as well as the length of the cochlea could explain the remaining one octave difference found when insertion angles were used, physiological phenomena (e.g., stimulation of the spiral ganglion cells) could also create this difference. From these data, analysis filters could be determined in sound coding strategies to match the pitch percepts elicited by electrode stimulation. This step might be of main importance for music perception and for the fitting of bilateral cochlear implants.

Acoustic Stimulation↗

PubMed2002

Temporal bone histopathology related to cochlear implantation in congenital malformation of the bony cochlea.

HYPOTHESIS: Histopathologic findings in temporal bones with congenital malformations of the bony cochlea may provide insight into cochlear implantation planning, surgical approach, and complications. BACKGROUND: Patients with congenitally malformed cochleae account for an increasing percentage of candidates for cochlear implantation. Few studies on the relationship between histopathologic findings of temporal bones with malformation of the bony cochlea and cochlear implantation have been reported. METHODS: We studied 21 temporal bones from 12 cases with congenital malformations of the bony cochlea. Ages ranged from stillborn to 50 years. Length of the cochleae and dimensions of facial recesses were measured with light microscopy. Other malformations associated with a shortened cochlea were determined, emphasizing how they affect cochlear implantation. RESULTS: The average length of the malformed cochlear duct was 22.84 +/- 0.69 mm. Average dimensions of facial recesses were not significantly different between malformed cochleae and the controls. Other malformations included enlarged cochlear aqueduct (43%), abnormal facial nerve course (57%), enlarged vestibular aqueduct (52%), aplasia of the middle ear (19%), malformed ossicles (67%), abnormal oval window (57%), and abnormal round window (29%). CONCLUSION: A shortened cochlear duct may cause an incomplete insertion of the implant electrode. Because dimensions of the facial recesses are similar to normal cases, a facial recess surgical approach is recommended. An enlarged cochlear aqueduct may cause perilymphatic oozing or gushing on fenestration of the cochlea. An anomalous course of the facial nerve is a common finding. Tympanic malformations such as round and oval window deformities and small middle ear cleft should be noted preoperatively to better guide surgery.

Adolescent↗

PubMed2005

A temporal bone study of insertion trauma and intracochlear position of cochlear implant electrodes. I: Comparison of Nucleus banded and Nucleus Contour electrodes.

In recent years, new designs of cochlear implant electrodes have been introduced in an attempt to improve efficiency and performance by locating stimulation sites closer to spiral ganglion neurons and deeper into the scala tympani. The goal of this study was to document insertion depth, intracochlear position and insertion trauma with the Nucleus Contour electrode and to compare results to those observed with the earlier generation Nucleus banded electrode. For this comparison eight Nuclears banded electrodes and 18 Contour electrodes were implanted in cadaver temporal bones using a realistic surgical exposure. Two experienced cochlear implant surgeons and two otology fellows with specialized training in cochlear implant surgery were selected for the study to represent a range of surgical experience similar to that of surgeons currently performing the procedure throughout the world. Following insertion of the electrodes, specimens were imaged using plain film X-ray, embedded in acrylic resin, cut in radial sections with the electrodes in place, and each cut surface was polished. Insertion depth was measured in digitized X-ray images, and trauma was assessed in each cross-section. The Contour electrode inserted more deeply (mean depth=17.9 mm or 417 degrees ) than the banded electrode (mean depth=15.3 mm or 285 degrees ). The incidence and severity of trauma varied substantially among the temporal bones studied. However, the nature and frequency of injuries observed with the two devices were very similar. The Contour electrode was clearly positioned closer to the modiolus than the banded model, and also appeared easier to use. Based on this difference in position and data from previous studies we conclude that the Contour electrode may provide lower thresholds and improved channel selectivity, but the incidence of trauma remains a problem with the newer design. The relative influences of electrode positioning and neural degeneration that may result from trauma are as yet unclear.

Cadaver↗

PubMed2004

Cochlear implants: indications in groups of patients with borderline indications. A review.

Cochlear implants (CI) represent the current treatment for patients affected by profound sensorineural hearing loss (SNHL). Initially only deaf adult patients were considered to be candidates for a CI; however, the development of technology and matured experience have expanded the indications for cochlear implantation. Today, CIs are implanted in adults and children and broader indications are followed. There are, however, a number of patients who do not completely fulfill the current indications and who are potential candidates for CI. The duration of deafness and residual hearing represent prognostic indicators for CI performance; however, the candidacy of children with residual hearing and prelingually deafened adults are still under debate. Anatomical variants such as cochlear ossification, cochlear malformation and chronic otitis media represented and still represent for some surgeons a contraindication to CI. The otological experience of CI surgeons and the advent of auditory brainstem implants have changed the approach to these patients, who may still benefit from hearing rehabilitation. This paper briefly analyses and reviews the results obtained in these groups of patients, who were not, at least initially, considered to be candidates for cochlear implantation.

Cochlea↗

PubMed1995

New processing strategies in cochlear implantation.

New strategies for representing acoustic information with multichannel cochlear implants have produced substantial improvements in speech recognition for implant users. This report reviews within-subject comparison of a new continuous interleaved sampling (CIS) strategy with a compressed analog (CA) strategy used in a standard clinical device. In general, the comparison show higher levels of open-set speech recognition with CIS for each of the 11 subjects studied. Data on the importance of the patients variable in determining outcomes with cochlear implants are presented. A brief description of another new strategy, the spectral maxima sound processor (SMSP) strategy is given as well as information on the availability of CIS in various implant systems.

Cochlear Implants↗

PubMed2006

Cochlear implantation in obstructed cochleas: the effect of the degree of obstruction on the number of activated electrodes and the amount of postoperative speech perception.

OBJECTIVE: With cochlear implantation, insertion of the electrodes can be hampered by cochlear obstructions. The aim of this study was to investigate the effects of these obstructions on the number of activated electrodes and postoperative speech perception. STUDY DESIGN AND SETTING: Retrospective analysis of the operation reports and CT-scans of patients who underwent cochlear implantation, at the Department of Otorhinolaryngology of the University Medical Center of Utrecht (n = 295). PATIENTS AND INTERVENTIONS: Fifty patients with a certain degree of cochlear obstruction were included. Based on the surgical intervention to overcome these obstructions they were subdivided into first-, second- and third degree obstructions. The number of implanted and activated electrodes was determined. MAIN OUTCOME MEASURES: Three different speech perception tests after 12 months of cochlear implant use. RESULTS: The number of activated electrodes significantly diminished with increasing obstruction degree (P < 0.01). This was caused by a lower amount of implanted electrodes combined with a higher amount of switched off electrodes. With a higher degree of obstruction the amount of postoperative speech perception decreased significantly (P < 0.01). This is partly explained by the lower number of activated electrodes and partly explained by the fact that a higher obstructions degree correlates with a higher degree of (retro-) cochlear pathology. Significantly more electrodes can be inserted into the severely obstructed cochlea using a Double Array Cochlear Implant. CONCLUSION: Cochlear obstructions pose a surgical threat and negatively influence the postoperative speech perception results. Fortunately, due to surgical techniques, first and second degree obstructed cochleas can often be bypassed. Implanting of a Double Array implant brightens the prospects of patients with third (severe) degree obstructed cochleas.

Audiometry, Speech↗

PubMed2002

Sound localization in patients with cochlear implant--preliminary results.

OBJECTIVES: To evaluate sound localization ability in patients with unilateral cochlear implant, who do not wear a hearing aid on the contralateral ear, and to try to improve this ability by training. SETTING: Tertiary academic referral center. METHODS: In the initial test, patients were exposed to sound stimuli from different directions and were asked to localize them. Following a training period the patients were re-evaluated by the same test. For each test, the percentage of correct answers and the final test score were calculated. RESULTS: In the initial test, the mean score of the study group of four cochlear implant users was 42.8 (out of a maximal score of 100), the mean rate of correct responses was 27.5%. Following a training period (6.5 sessions on the average), on the final test the mean score of the group was 74.3, while the mean rate of correct responses was 66.5%. CONCLUSIONS: The results demonstrated that patients with unilateral cochlear implant have some ability to localize sound, and that this ability may be improved by regular training.

Adolescent↗

PubMedDate not supplied

Realization of complex onsets by pediatric users of cochlear implants.

This study examined variations in English complex onset realizations by children who use cochlear implants. Data consisted of 227 productions of two-segment onset clusters from 12 children. In general, onset cluster realizations of children with cochlear implants did not differ markedly from those reported for children with normal hearing: null realizations were rare or nonexistent, there were few epenthetic realizations, one-segment realizations generally respected sonority principles, and two-segment realizations reflected singleton constraints. Further examination also revealed that the basis for variation among the children with cochlear implants could be attributed to differences in constraint rankings within Optimality Theory. Differences in constraint rankings could thus account for variations in the number of output segments, in the role of sonority in reduction, and in relationships between segmental and featural faithfulness.

Adolescent↗

PubMed2004

Electrophysiologic effects of placing cochlear implant electrodes in a perimodiolar position in young children.

OBJECTIVE: The purpose of this study was to intraoperatively record the electrically evoked auditory brainstem response (EABR) before and after placement of the electrode positioning system (EPS) (CII Bionic Ear with HiFocus I cochlear implant electrode array) as well as before and after stylet removal (Nucleus Contour cochlear implant electrode array). It was hypothesized that physiologic changes would occur after perimodiolar positioning of the electrode array and these changes would be evident from the EABR recordings. STUDY DESIGN: Consecutive young (11-36 month old) pediatric cochlear implant recipients (n = 17) had intraoperative EABRs recorded from three intracochlear electrodes that represented apical, medial, and basal locations. Wave V amplitudes and thresholds were studied relative to electrode location and pre- versus postperimodiolar positioning. These evoked potential measures were analyzed for statistical significance. SETTING: Tertiary referral children's hospital/medical college. RESULTS: Wave V thresholds of the EABR were lower, and amplitudes were larger after perimodiolar positioning, although the changes were dependent on electrode location and implant design. Statistically significant decreases in EABR wave V threshold and increases in suprathreshold wave V amplitude were found for the basal electrode for the CII Bionic Ear HiFocus I and for the apical electrode for the Nucleus Contour. CONCLUSIONS: Placement of either the CII Bionic Ear HiFocus I or Nucleus Contour cochlear implant electrode array in the perimodiolar position in young children resulted in less electrical current necessary to stimulate the auditory system. Changes in electrophysiologic thresholds and amplitudes, measured with EABR, indicate that the electrode array is placed closer to the modiolus with both electrode designs.

Child, Preschool↗

PubMedDate not supplied

Design and function: a physical and electrical description of the 3M House cochlear implant system.

A patient-wearable, single-electrode cochlear implant was first used by a patient in 1972 at the House Ear Institute. Since early 1982, a redesigned version of this system has been in clinical use. This new system, called the 3M House cochlear implant system, consists of an implanted receiver and a patient-worn signal processor, transmitter, and microphone. Also available are instruments to assist the audiologist and patient in proper fitting and testing of the equipment. Physical and electrical characteristics of the devices are described, with attention given to improvements over the older system and features important to the use in children.

Auditory Threshold↗

PubMed2002

Pediatric cochlear implantation in auditory neuropathy.

OBJECTIVE: Auditory neuropathy (AN) is characterized by varying degrees of sensorineural hearing loss, an absent or severely abnormal auditory brainstem response, and normal otoacoustic emissions. The nomenclature for this condition reflects the concept that the site of lesion is proximal to the cochlea (e.g., cochlear nerve). Given this hypothesis, it is reasonable to expect limited benefit from cochlear implantation in patients with AN. However, a growing body of evidence shows the striking benefits of cochlear implantation in AN. To explore this topic, we reviewed our population of children with AN and, specifically, the performance results in those children having undergone cochlear implantation. STUDY DESIGN: A retrospective case review of those patients diagnosed with AN from 1993 to 2001. SETTING: A tertiary pediatric referral center. PATIENTS: A diagnosis of AN reported from the Center for Hearing and Deafness Research, Cincinnati, OH, database. RESULTS: Eighteen patients were diagnosed with AN (11 girls, 7 boys), with 3 sets of siblings, including 1 set of identical twins. Four patients with AN underwent implantation in the previous 5 years. Twelve out of the 18 patients had classic risk factors for AN (e.g., prematurity and hyperbilirubinemia). The degree of hearing loss varied in our patients, with a majority showing severe to profound deficits. All children with implants showed improvement in auditory and verbal development, but this improvement was variable. CONCLUSION: The success of cochlear implantation in these patients suggests that some children with AN have an auditory system lesion that can be compensated for by cochlear implantation. This implies either an inner hair cell or inner hair cell-cochlear nerve junctional pathology that can be overcome by direct electrical stimulation.

Audiometry, Pure-Tone↗