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PubMed1998

Single-channel to multichannel conversions in adult cochlear implant subjects.

OBJECTIVE: This study aimed to compare open-set speech perception of single-channel with multichannel cochlear implants in the same ear of postlingually deafened adults. STUDY DESIGN: The study design was a retrospective case and literature review. SETTING: The study was conducted at a tertiary referral center with an associated veterans administration hospital. PATIENTS: Postlingually deafened adults with at least 6 months of experience with a single-channel cochlear implant were studied. INTERVENTION: Replacement of a single-channel with a multichannel cochlear implant in the same ear was performed. MAIN OUTCOME MEASURES: Open-set word and sentence perception scores at least 6 months after single-channel implantation and multichannel reimplantation were measured. RESULTS: Six of six patients had substantial improvement in open-set speech recognition after reimplantation of the same ear. CONCLUSIONS: Removal of a functioning single-channel implant and replacement with a multichannel device are appropriate in postlingually deafened adults who desire better speech recognition.

Adult↗

PubMed2004

Effects of speech processing strategy on Chinese tone recognition by nucleus-24 cochlear implant users.

OBJECTIVE: To evaluate the effects of speech processing strategy on Chinese tone recognition by Nucleus-24 cochlear implant users. METHODS: Recognition of Chinese tones was measured with the spectral peak (SPEAK), advanced combination encoders (ACE), and continuous interleaved sampling (CIS) strategies in nine Nucleus-24 cochlear implant users. Recognition of Chinese sentences was also measured with the ACE strategy (1200 pulse-per-sec on each electrode). As the stimulation rate in the SPEAK processor is fixed at 250 pulses per sec per electrode (ppspe), only one stimulation rate was tested with the SPEAK processor. Three stimulation rates (900, 1200, and 1800 ppspe) were tested in the ACE processing conditions. Four stimulation rates (1200, 1800, 2400, and 3600 ppspe) were tested in the CIS processing conditions. Because the number of stimulating electrodes determines the stimulation rate in CIS processors, the number of electrodes was reduced from 12 to 8 to 6 to 4 to achieve stimulation rates of 1200, 1800, 2400, to 3600 pps. RESULTS: Results showed that mean Chinese tone recognition scores with the ACE and CIS strategies were significantly higher than those with the SPEAK strategy. For the ACE strategy, there was no significant difference in performance among the various stimulation rates (for the ACE processing conditions, the stimulation rate was varied while keeping the number of stimulating electrodes constant). For the CIS strategy, there was no significant difference among the various stimulation rates and electrode configurations (for the CIS processing conditions, the stimulation rate was varied by changing the number of stimulating electrodes). There was also a significant correlation between Chinese tone recognition and the recognition of everyday sentences. CONCLUSIONS: The latest-generation speech processing strategies were able to provide cochlear implant users with considerable amounts of tonal information. However, Chinese tone recognition was significantly affected by the choice in speech processing strategy. Relatively higher stimulation rates (>900 ppspe) may improve Chinese tone recognition. Furthermore, it may be necessary to develop speech processing strategies to specifically improve tone recognition, which is critical for understanding tonal languages.

Adult↗

PubMed2006

How we do it: patient participation in cochlear implant selection.

. Involving patients and parents in the choice of their cochlear implant encourages an active role in the process and facilitates 'bonding' and 'ownership' of the device. . The most frequent reasons given by patients for selecting a device included cochlear implant comfort and appearance. . We describe the Implant Programme based at the Royal National Throat, Nose and Ear Hospital, London, and also examine patient satisfaction with the scheme.

Adult↗

PubMed2005

Place-pitch discrimination of single- versus dual-electrode stimuli by cochlear implant users (L).

Simultaneous or near-simultaneous activation of adjacent cochlear implant electrodes can produce pitch percepts intermediate to those produced by each electrode separately, thereby increasing the number of place-pitch steps available to cochlear implant listeners. To estimate how many distinct pitches could be generated with simultaneous dual-electrode stimulation, the present study measured place-pitch discrimination thresholds for single- versus dual-electrode stimuli in users of the Clarion CII device. Discrimination thresholds were expressed as the proportion of current directed to the secondary electrode of the dual-electrode pair. For 16 of 17 electrode pairs tested in six subjects, thresholds ranged from 0.11 to 0.64, suggesting that dual-electrode stimuli can produce 2-9 discriminable pitches between the pitches of single electrodes. Some subjects demonstrated a level effect, with better place-pitch discrimination at higher stimulus levels. Equal loudness was achieved with dual-electrode stimuli at net current levels that were similar to or slightly higher than those for single-electrode stimuli.

Aged↗

PubMed2004

Criteria of candidacy for unilateral cochlear implantation in postlingually deafened adults I: theory and measures of effectiveness.

OBJECTIVES: The objectives of this study were to distinguish the equivalent-effectiveness, health-economic, and actuarial approaches to specifying criteria of candidacy for medical interventions; to apply the equivalent-effectiveness approach to unilateral cochlear implantation for postlingually deafened adults; and to determine whether the criterion should take age at implantation and duration of profound deafness into account. DESIGN: The study was designed as a prospective cohort study in 13 hospitals with four groups of severely-profoundly hearing-impaired subjects distinguished by their preoperative ability to identify words in sentences when aided acoustically. The groups represent a progressive relaxation of criteria of candidacy: Group I (N=134) scored 0% correct without lipreading and did not improve their lipreading score significantly when aided; group II (N=93) scored 0% without lipreading but did improve their lipreading score significantly when aided; group III (N=53) scored 0% without lipreading when the to-be-implanted ear was aided but between 1% and approximately 50% when the other ear was aided. Group IV (N=31) scored between 1% and approximately 50% without lipreading when the to-be-implanted ear was aided. Measures of speech intelligibility, health utility, and otologically relevant quality of life were obtained before surgery and 9 mo after surgery from each subject. Measures of effectiveness were calculated as the difference between 9-mo and preoperative scores. RESULTS: Effectiveness differed only slightly between groups. Effectiveness was not strongly associated with age at the time of implantation. Greater effectiveness was associated with implantation in the ear with the shorter duration of profound deafness. Cochlear implantation was least effective when the preoperative audiological status of the better-hearing ear was good and the duration of profound deafness of the implanted ear was long. As a result, effectiveness was not significant for the subsets of groups III and IV, who were given implants in ears that had been profoundly deaf for more than 30 yr. CONCLUSIONS: The effectiveness of cochlear implantation differs little between groups of candidates who score zero with acoustic hearing aids before surgery and groups who score up to approximately 50% correct, thereby justifying a relaxation of the criterion of candidacy to embrace some members of the latter groups. The criterion should be based not only on preoperative speech intelligibility but also on duration of profound deafness in the to-be-implanted ear.

Adolescent↗

PubMed1996

Speech perception and speech production skills of children with multichannel cochlear implants.

The acquisition of speech perception and speech production skills emerges over a protracted time course in congenitally deaf children with multichannel cochlear implants (CI). Only through comprehensive, longitudinal studies can the full impact of cochlear implantation be assessed. In this study, the performance of CI users was examined longitudinally on a battery of speech perception measures and compared with subjects with profound hearing loss who used conventional hearing aids (HA). The average performance of the multichannel cochlear implant users gradually increased over time and continued to improve even after 5 years of CI use. Speech intelligibility was assessed from recordings of the subjects' elicited speech and played to panels of listeners. Intelligibility was scored in terms of percentage of words correctly understood. The average scores for subjects who had used their CI for 4 years or more exceeded 40%.

Child, Preschool↗

PubMed2005

Restoration of auditory nerve synapses in cats by cochlear implants.

Congenital deafness results in abnormal synaptic structure in endings of the auditory nerve. If these abnormalities persist after restoration of auditory nerve activity by a cochlear implant, the processing of time-varying signals such as speech would likely be impaired. We stimulated congenitally deaf cats for 3 months with a six-channel cochlear implant. The device used human speech-processing programs, and cats responded to environmental sounds. Auditory nerve fibers exhibited a recovery of normal synaptic structure in these cats. This rescue of synapses is attributed to a return of spike activity in the auditory nerve and may help explain cochlear implant benefits in childhood deafness.

Acoustic Stimulation↗

PubMed1999

Speech perception of young children using nucleus 22-channel or CLARION cochlear implants.

This study compares the auditory perceptual skill development of 23 congenitally deaf children who received the Nucleus 22-channel cochlear implant with the SPEAK speech coding strategy, and 20 children who received the CLARION Multi-Strategy Cochlear Implant with the Continuous Interleaved Sampler (CIS) speech coding strategy. All were under 5 years old at implantation. Preimplantation, there were no significant differences between the groups in age, length of hearing aid use, or communication mode. Auditory skills were assessed at 6 months and 12 months after implantation. Postimplantation, the mean scores on all speech perception tests were higher for the Clarion group. These differences were statistically significant for the pattern perception and monosyllable subtests of the Early Speech Perception battery at 6 months, and for the Glendonald Auditory Screening Procedure at 12 months. Multiple regression analysis revealed that device type accounted for the greatest variance in performance after 12 months of implant use. We conclude that children using the CIS strategy implemented in the Clarion implant may develop better auditory perceptual skills during the first year postimplantation than children using the SPEAK strategy with the Nucleus device.

Child, Preschool↗

PubMed1995

Cochlear implants in young children with Usher's syndrome.

Usher's syndrome (US) is an autosomal recessive disorder characterized by congenital sensorineural hearing loss and retinitis pigmentosa. The majority of affected individuals have severe to profound sensorineural hearing loss and are therefore potential cochlear implant candidates. A goal of our otology program has been early identification and implantation of children with US. At our center, early diagnosis of US has been achieved by comprehensive ophthalmologic evaluation including electroretinography. Four of our 19 pediatric cochlear implant recipients with congenital sensorineural hearing loss were identified with US and implanted prior to the onset of signs or symptoms of visual loss. All children have received measurable benefit from cochlear implantation. In light of the dual sensory deficits present in US, the need for early diagnosis and cochlear implantation is of special importance in this population.

Child↗

PubMed1986

Reacquisition of contrastive stress in an adventitiously deaf speaker using a single-channel cochlear implant.

Acoustic correlates of contrastive stress, i.e., fundamental frequency (F0), duration, and intensity, and listener perceptions of stress, were investigated in a profoundly deaf subject (RS) pre/post single-channel cochlear implant and longitudinally, and compared to the overall patterns of age-peer profoundly deaf (JM) and normally hearing subjects (DL). The stimuli were a group of general American English words in which a change of function from noun to verb is associated with a shift of stress from initial to final syllable, e.g., CON'trast versus conTRAST'. Precochlear implant, RS was unable to produce contrastive stress correctly. Hearing one day post-stimulation resulted in significantly higher F0 for initial and final stressed versus unstressed syllables. Four months post-stimulation, RS maintained significantly higher F0 on stressed syllables, as well as generalization of significantly increased intensity and longer syllable duration differences for all stressed versus unstressed syllables. Perceptually, listeners judged RS's contrastive stress placement as incorrect precochlear implant and as always correct post-cochlear implant. JM's contrastive stress was judged as 96% correct, and DL's contrastive stress placement was 100% correct. It was concluded that RS reacquired all acoustic correlates needed for appropriate differentiation of contrastive stress with longitudinal use of the cochlear implant.

Acoustic Stimulation↗

PubMed2006

Multichannel cochlear implantation in the scala vestibuli.

OBJECTIVE: Sensorineural hearing loss resulting from otosclerosis, meningitis, chronic otitis media, autoimmune ear disease, and trauma can be associated with partial or total obstruction of the cochlear scalae. Multichannel cochlear implantation may be difficult in a cochlea with an obstructed scala tympani. The purpose of this study is to determine the safety and efficacy of scala tympani electrode insertion. STUDY DESIGN: Retrospective chart review. SETTING: Academic medical center. PATIENTS: Eight children and adults with profound sensorineural hearing loss who underwent cochlear implantation with known scala vestibuli electrode array insertion were subjects for this study. INTERVENTIONS: Eight study subjects underwent implantation: five with the Nucleus 24RCS (Contour) device and three with the Nucleus 24M device. OUTCOME MEASURES: Imaging findings, operative findings, and age-appropriate speech perception testing. RESULTS: All patients had full electrode insertion. Various obstructive patterns on computed tomography and magnetic resonance imaging were found, and there was a range of speech perception results. All but one patient improved based on age-appropriate monosyllabic word and sentence tests. CONCLUSION: Scala vestibuli multielectrode insertion is a viable alternative when scala tympani insertion is not possible because of abnormal anatomy or anatomical changes secondary to disease or previous implantation. We will also present an algorithm of options for decision making for implantation when encountering cochlear obstruction and difficult electrode insertion.

Aged↗

PubMed2006

Effects of auditory feedback on fricatives produced by cochlear-implanted adults and children: acoustic and perceptual evidence.

Acoustic analyses and perception experiments were conducted to determine the effects of brief deprivation of auditory feedback on fricatives produced by cochlear implant users. The words /si/ and /Si/ were recorded by four children and four adults with their cochlear implant speech processor turned on or off. In the processor-off condition, word durations increased significantly for a majority of talkers. These increases were greater for children compared to adults, suggesting that children may rely on auditory feedback to a greater extent than adults. Significant differences in spectral measures of /S/ were found between processor-on and processor-off conditions for two of the four children and for one of the four adults. These talkers also demonstrated a larger /s/-/S/ contrast in centroid values compared to the other talkers within their respective groups. This finding may indicate that talkers who produce fine spectral distinctions are able to perceive these distinctions through their implants and to use this feedback to fine tune their speech. Two listening experiments provided evidence that some of the acoustic changes were perceptible to normal-hearing listeners. Taken together, these experiments indicate that for certain cochlear-implant users the brief absence of auditory feedback may lead to perceptible modifications in fricative consonants.

Adult↗

PubMed2002

Cochlear implantation in a patient with superficial siderosis of the central nervous system.

OBJECTIVE: To perform an assessment of the viability of cochlear implantation in a patient with superficial siderosis of the brain. STUDY DESIGN: Case review. SETTING: Tertiary referral center. PATIENTS: Patient with superficial siderosis of the brain. INTERVENTION: Cochlear implantation. MAIN OUTCOME MEASURES: Electrically evoked auditory brainstem responses and fitting strategy for cochlear implant based on patient's subjective responses. RESULTS: After some time, C levels and T levels showed a pattern comparable with the evoked auditory brainstem responses. CONCLUSIONS: Bilateral profound hearing loss after superficial siderosis of the brain is no absolute contraindication for implantation. Furthermore, evoked auditory brainstem measurements can potentially guide the fitting process of the implant in difficult cases.

Brain Diseases↗

PubMedDate not supplied

Comparison of promontory and cochlear implants within a single subject.

Audiometric pure tone, speech, and psychoacoustic data were obtained from a patient who had worn a promontory electrode for two years. Subsequently the promontory implant was replaced by a scala tympani electrode (cochlear implant) and testing was repeated. Warbled tone thresholds ranged from 52-68 dB SPL for the octave frequencies 250-8000 Hz with the cochlear implant (CI), and from 65-74 dB SPL with the promontory electrode (PE). Speech discrimination scores were better with the CI than with the PE, although performance on an environmental sounds test was slightly better with the PE. Smaller intensity difference limens (DLs) were obtained with the CI (1 dB) than with the PE (about 4 dB). Frequency discrimination was poor with both electrode systems. The CI provided better frequency DLs at 250, 500, and 1000 Hz; the PE produced better DLs at 2000 Hz. When the CI was combined with a hearing aid worn on the better implanted ear, performance improved over that with either prosthesis alone.

Aged↗

PubMed2005

A model for cochlear implant electrode insertion and force evaluation: results with a new electrode design and insertion technique.

OBJECTIVES AND HYPOTHESIS: This study has the specific aim of evaluating the insertion characteristics of a new cochlear implant electrode. Techniques for evaluation of fluoroscopic real time mechanical insertion dynamics, histologic electrode position and trauma results, hydraulic force, and mechanical insertion forces are presented. In addition, this study should serve to present a novel model for cochlear implant electrode insertion evaluations. STUDY DESIGN: Prospective analysis using a series of analytical techniques. METHODS: All studies are conducted in fixed cadaveric temporal bones. Real time fluoroscopic insertion evaluations, histologic evaluations for trauma and electrode position in embedded bones, hydraulic measures, and mechanical intracochlear force measurements are conducted with a current and new electrode. RESULTS: The Contour Advance electrode provides a more reliable and less traumatic insertion when deployed with the Advance Off Stylet technique. This is largely because of a reduction in intracochlear outer wall force generation. Fluoroscopic and histologic analysis reveal a smooth insertion without reliance on cochlear outer wall contact. No hydraulic forces were detected when measured from the superior semicircular canal ampulla. CONCLUSION: The model used for this study provides valuable information to cochlear implant surgeons and design engineers. The Contour Advance electrode, inserted with the Advance Off Stylet technique, represents an improvement over the Contour electrode inserted with the standard insertion technique.

Cadaver↗

PubMed1998

Somatosensory phenomena after multichannel cochlear implantation in prelingually deaf adults.

OBJECTIVES: Central auditory system development in thought to be dependent on normal auditory nerve excitation. Central auditory disorganization may differ between prelingual and postlingual deafness. One possible clinical manifestation of such central auditory disorganization is somatosensory perception with cochlear implant stimulation. The purpose of this study was to investigate the incidence and characteristics of somatosensory phenomena in prelingually and postlingually deafened adult cochlear implant subjects. STUDY DESIGN: The study design was a retrospective analysis. SETTING: The study was performed at an academic tertiary referral center. PATIENTS: This study included 32 adult multichannel cochlear implant recipients. MAIN OUTCOME MEASURES: Subjective patient reporting of sensory perception after cochlear implant stimulation was reviewed. RESULTS: All 10 prelingually deaf subjects noted somatosensory phenomena distant from the implanted ear (e.g., chest, abdomen) on implant stimulation. These sensations resolved gradually for all patients. No subject deafened after the age of 2 years reported somatosensory perceptions. CONCLUSIONS: Somatosensory phenomena experienced by prelingually deafened adults suggest that disorganization of central auditory system pathways is more severe in these individuals. Earlier auditory deprivation appears to produce greater central auditory alterations, and perceptible crossover between somatosensory and auditory signals may be the end result.

Adult↗

PubMed2001

Effects of the Clarion Electrode Positioning System on auditory thresholds and comfortable loudness levels in pediatric patients with cochlear implants.

OBJECTIVE: To evaluate the effects of using the Electrode Positioning System on psychophysical auditory thresholds, most comfortable loudness levels, and electric auditory brainstem response (EABR) thresholds in children with the Clarion version 1.2 cochlear implant. DESIGN: Retrospective analysis. SETTING: Academic tertiary care center. PATIENTS AND METHODS: Clinical records of a series of 25 children who received the Clarion version 1.2 cochlear implant at the University of Minnesota, Minneapolis, between January 1997 and August 1999 were examined. Measures evaluated were psychophysical thresholds (T-levels) and most comfortable loudness levels (M-levels) obtained at the 3-month posthookup audiologic evaluation and EABR thresholds obtained during implant surgery. Relevant threshold measures were available for 24 patients, 11 of whom had received the Clarion spiral electrode and electrode positioner (EP group) and 13 of whom had received the spiral electrode without positioner (non-EP group). The 3 measures (T-levels, M-levels, and EABR thresholds) were compared across groups. In addition, EABR thresholds were compared with T-levels and M-levels within groups. RESULTS: Mean T-levels and M-levels were significantly lower for the EP group than for the non-EP group, and interpatient variability for these measures was considerably smaller in the EP group. Electric auditory brainstem response thresholds were not significantly different for EP vs non-EP patients; however, EABR data were available for only a few non-EP patients. CONCLUSIONS: Use of the electrode positioner results in lower T-levels and M-levels in children with the Clarion version 1.2 cochlear implant, consistent with results of previous studies in adults, and reduces across-patient variability for these measures. It is unclear from the present data whether use of the electrode positioner systematically reduces intraoperative EABR thresholds.

Auditory Threshold↗

PubMed2006

Hearing-impaired children in the United Kingdom, II: Cochlear implantation and the cost of compulsory education.

OBJECTIVE: The objective of this study was to estimate the impact of cochlear implantation on the cost of compulsory education of hearing-impaired children in the United Kingdom. STUDY DESIGN: In a cross-sectional survey, teachers were asked to report the school placement of, and amount of support provided to, a representative sample of hearing-impaired children. Costs of school placement were obtained from published sources. Costs of support were calculated from a survey of 11 special education services. The annual education cost (in euros at 2001/2002 levels) of each child was calculated by summing the placement and support costs. Linear regression analyses calculated the association between annual education cost and possession of an implant while controlling nine other variables: average (unaided, preoperative) hearing level (AHL), age at onset of hearing impairment, age, gender, the number of additional disabilities, parental occupational skill level, ethnicity, parental hearing status, and academic achievement. RESULTS: Data were received for 2241 children, 383 of whom had cochlear implants. Mean annual education cost ranged from 15,745 euros for children with moderate hearing impairments to 30,071 euros for nonimplanted children with profound hearing impairments and was 28,058 euros for implanted children. A lower annual education cost was associated with a more favorable AHL, a later age at the onset of hearing impairment, female gender, a younger age, fewer additional disabilities, and a higher level of academic achievement. When these variables were controlled, costs were lower on average for implanted compared with nonimplanted children for the subset of children whose AHLs exceeded 111 dB. At the mean AHL of the implanted children (115 dB), implantation was associated with a reduction of 3105 euros (95% confidence interval, 1105 euros to 5106 euros) in annual education costs. CONCLUSIONS: Pediatric cochlear implantation is sufficiently effective to influence resource-allocation decisions in the education sector. The health-service cost of implantation is partly offset by savings in the cost of education. These savings occur without detriment to academic achievements.

Adolescent↗