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 1,567 records · Page 87Linked to original sources

PubMed2006

Cost-utility analysis of cochlear implants in Korea using different measures of utility.

CONCLUSIONS: All cost-utility ratios obtained using the various measures of utility except quality well-being (QWB) were below 25,000 dollars per quality-adjusted life year (QALY). Therefore, treatment of post-lingual deaf adults with cochlear implants improves the quality of life at a reasonable direct cost and appears to produce net savings for Korean society. OBJECTIVES: To determine the quality of life and the cost consequences of cochlear implants for deaf adults. PATIENTS AND METHODS: We performed a cost-utility analysis using data from 11 post-lingual deaf adults who had received cochlear implants between 1990 and 2002 in Seoul, Korea. The average age of the participants was 49.6 years. The main outcome was the direct cost per QALY calculated using the visual analog scale (VAS), health utility index (HUI), EuroQol (EQ-5D) measure and QWB measure. Costs and utility were discounted 3% annually. RESULTS: Recipients used implants for an average of 5.6 years. The mean VAS, HUI, EQ-5D, and QWB score increased by 0.33 (from 0.27 before implantation to 0.60 at survey), 0.36 (0.29 to 0.65), 0.26 (0.52 to 0.78), and 0.16 (0.45 to 0.61), respectively. The discounted direct cost was 22,320 dollars, which yielded a cost-utility ratio of 19,223 dollars per QALY using VAS, 17,387 dollars per QALY using HUI, 24,604 dollars per QALY using EQ-5D, and 40,474 dollars per QALY using QWB.

Adult↗

PubMed1996

Frequency discrimination and speech recognition by patients who use the Ineraid and continuous interleaved sampling cochlear-implant signal processors.

Patients who use the Ineraid cochlear implant were tested in four experiments with materials which assessed frequency discrimination and speech understanding. In each experiment both frequency discrimination and speech recognition varied among patients. Correlations between the two measures were significant and ranged from 0.60 to 0.83. Most generally, frequency discrimination was better in the frequency domain of F1 than in the domain of F2. In experiment 5, both the Ineraid signal processing strategy and a continuous interleaved sampling (CIS) strategy were implemented for a single patient. The CIS strategy improved frequency discrimination in the domain of F2 and improved speech understanding.

Adult↗

PubMed2000

The effect of parametric variations of cochlear implant processors on speech understanding.

This study investigated the effect of five speech processing parameters, currently employed in cochlear implant processors, on speech understanding. Experiment 1 examined speech recognition as a function of stimulation rate in six Med-E1/CIS-Link cochlear implant listeners. Results showed that higher stimulation rates (2100 pulses/s) produced a significantly higher performance on word and consonant recognition than lower stimulation rates (<800 pulses/s). The effect of stimulation rate on consonant recognition was highly dependent on the vowel context. The largest benefit was noted for consonants in the /uCu/ and /iCi/ contexts, while the smallest benefit was noted for consonants in the /aCa/ context. This finding suggests that the /aCa/ consonant test, which is widely used today, is not sensitive enough to parametric variations of implant processors. Experiment 2 examined vowel and consonant recognition as a function of pulse width for low-rate (400 and 800 pps) implementations of the CIS strategy. For the 400-pps condition, wider pulse widths (208 micros/phase) produced significantly higher performance on consonant recognition than shorter pulse widths (40 micros/phase). Experiments 3-5 examined vowel and consonant recognition as a function of the filter overlap in the analysis filters, shape of the amplitude mapping function, and signal bandwidth. Results showed that the amount of filter overlap (ranging from -20 to -60 dB/oct) and the signal bandwidth (ranging from 6.7 to 9.9 kHz) had no effect on phoneme recognition. The shape of the amplitude mapping functions (ranging from strongly compressive to weakly compressive) had only a minor effect on performance, with the lowest performance obtained for nearly linear mapping functions. Of the five speech processing parameters examined in this study, the pulse rate and the pulse width had the largest (positive) effect on speech recognition. For a fixed pulse width, higher rates (2100 pps) of stimulation provided a significantly better performance on word recognition than lower rates (<800 pps) of stimulation. High performance was also achieved by jointly varying the pulse rate and pulse width. The above results indicate that audiologists can optimize the implant listener's performance either by increasing the pulse rate or by jointly varying the pulse rate and pulse width.

Adult↗

PubMed2002

Cost-benefit analysis of pediatric cochlear implantation: German experience.

HYPOTHESIS: To explore, from the payers' perspective, the cost-benefit ratio of pediatric cochlear implantation for congenitally deaf and prelingually deafened children compared with children with hearing aids. The study should verify the hypothesis that educational and associated costs increase with age at implantation and that these can be below costs for children with hearing aids. METHODS: Children who received implants at the Medical University of Hanover at different ages (Group 1, 0-1.9 yr; Group 2, 2-3.9 yr; Group 3, 4-6.9 yr) were compared with deaf children using hearing aids (Group 4). Sick funds were the payers for direct and indirect costs, and public authorities were the payers for educational costs. Educational settings were used to measure for benefits. All costs related to the hearing deficiency were included up to the age of 16 years on the basis of 1999 currency values. A scenario analysis was used to explore the impact of variation of costs and discount rates. RESULTS: Total costs for the three age groups of children with implants were from euro 138,000 (approximately US$113,100) to euro 177,000 (approximately US$152,700), compared with euro 160,000 (approximately US$138,000) for hearing aid users. CONCLUSION: This study supports the view that pediatric cochlear implantation provides positive cost-benefit ratios compared with hearing aid users, depending on the age at implantation. Implantation is strongly recommended from the payers' perspective for children implanted before the age of 2 years.

Child↗

PubMed2005

Cochlear implantation in patients with osteogenesis imperfecta.

OBJECTIVE: Hearing loss has been shown to occur in 42% to 58% of patients with osteogenesis imperfecta (OI), with deafness arising in 25% to 60% of the patients. Implantation in patients with OI is relatively rare, with only 4 prior single case reports published in the English-language literature. The goal of this study was to evaluate the feasibility and functional outcome of cochlear implantation in 2 patients with OI tarda type I with profound sensorineural hearing loss. STUDY DESIGN: Case series. SETTING: The implantations were performed in a tertiary academic referral center (Johns Hopkins University). RESULTS: Though promontory vascularity was encountered, full insertion of a normal cochlear implant array could be achieved in both cases. One-year postimplant scores demonstrated 20 to 40 dB hearing thresholds, Consonant-Nucleus-Consonant Test word scores of 54% and 70%, Consonant-Nucleus-Consonant Test phoneme scores of 75% and 83%, Hearing in Noise Test scores of 76% and 99%, and Central Institute of the Deaf Sentence Score sentence scores of 99% and 100%, for patients 1 and 2, respectively. CONCLUSIONS: Cochlear implantation in patients with OI is not only technically possible but the results are similar to implant outcomes for patients with sensorineural hearing loss from a variety of other causes. EBM RATING: C.

Adult↗

PubMed2004

Quality of life in hearing-impaired adults: the role of cochlear implants and hearing aids.

OBJECTIVE: To compare the quality-of-life (QOL) benefit received from cochlear implants (CIs) and hearing aids (HAs) among hearing-impaired adults. STUDY DESIGN: Health-related questionnaire. METHODS: Twenty-seven CI users compared to control group of 54 HA users, both older than 49. Questionnaires for the pre-rehab state (without HA or CI use) and post-rehab state (after HA or CI for 12 months) were mailed 2 weeks apart. RESULTS: Twenty-six (96.3%) CI and 30 (55.6%) HA users responded (P < 0.001, chi-square). Compared to HA patients, CI users showed twice as much overall QOL improvement (P = 0.082, multiple linear regression) as HA users. Multivariate analysis of variance showed greater QOL benefit in CI than HA users across the physical, psychological, and social subdomains (P = 0.03). CONCLUSION: Cochlear implants provide at least comparable benefit for those with profound hearing loss as hearing aids bring for those with less severe hearing loss.

Activities of Daily Living↗

PubMed2004

Tone perception of Cantonese-speaking prelingually hearing-impaired children with cochlear implants.

OBJECTIVE: To evaluate tone perception performance in Cantonese-speaking prelingually hearing-impaired children with cochlear implants. STUDY DESIGN AND SETTING: The ability to discriminate and identify Cantonese tones was evaluated on 17 native Cantonese-speaking prelingually hearing-impaired children. Performance was correlated to factors like age of implantation and general communication ability. RESULTS: Subjects' performance in discrimination and identification tasks was slightly above chance level. Although variations in the contour fundamental frequency of the tones provided some cues for tone discrimination, these distinctions proved insufficient for subjects to perform well. Tone 6 (low level tone) was the most difficult to identify. Subjects' performance did not correlate with gender, age of implantation, duration of implant use, frequency of auditory training session, or general communication ability. CONCLUSION: Although some children were able to discriminate and/or identify Cantonese tones, their performance was poor. Further studies are needed to understand how tone perception relate to daily speech understanding. SIGNIFICANCE: Cochlear implant speech coding strategies may need modification to optimize tone perception.

Acoustic Stimulation↗

PubMed1991

Complications of cochlear implant surgery in adults and children.

Surgery for cochlear prosthesis insertion exposes the patient to several potential risks. We review the surgical complication experience with cochlear implants in the United States. There have been no deaths attributable to these devices, few serious major complications, and relatively few minor complications. Major complications usually have to do with surgical technique and include flap necrosis, improper electrode placement, and rare facial nerve problems. Minor complications include dehiscence of incisions, infection, facial nerve stimulation, dizziness, and pedestal problems with the Ineraid device. Complications were less frequent in children than adults and were more likely to occur in the younger children than those above the age of 7 years. Complications were still fewer in groups of patients operated on within tightly controlled protocols. There was no increased incidence of otitis media in children who received the Nucleus Mini-22 device, and no reported sequelae from such otitis when it occurred.

Adult↗

PubMed1981

[Multiple electrode cochlear implants : clinical results (author's transl)].

Multiple electrode cochlear implants were employed in 34 patients with total deafness (25 cases of acquired deafness of an adult age, and 22 cases of congenital or neonatal deafness). Complications encountered initially (eardrum perforation, receiver breakdown) are no longer observed, but emphasis has also to be placed on the reliability of the electrode-nerve interface, which remained unaltered after a follow-up period of nearly five years. The advantages of the method are that it enables frequency discrimination, followed by that of phonemes and finally words and phrases, without the need for up-reading, results being variable from one case to another. Results are dependent on the effectiveness of the electrode-nerve interface and the intellectual development of the patient. Only measurable objective results are reported.

Adolescent↗

PubMed1998

Monte Carlo simulation of tuning capacitor selection in a cochlear implant.

The principles of Monte Carlo simulation are applied to critical manufacturing process in the construction of cochlear implants. In this application, the tuning of the implant's radio frequency (RF) communication system is dependent upon a "select on test" tuning capacitance. The aim is to accurately predict the usage of capacitors of a given size in future production of cochlear implants using Monte-Carlo simulation. The predicted quantities may then be purchased from a supplier to satisfy the requirements of high volume manufacturing without maintaining unnecessary and expensive stock levels of infrequently or never used capacitors. Simulations indicate that for large production runs, prediction of the necessary quantities of particular tuning capacitor sizes may enable the implant manufacturer to reduce their capacitor stock levels by as much as 82 percent. This significant reduction is in comparison to maintaining a uniform stock level of all sizes of capacitors, assuming random probability of requiring each size of tuning capacitor.

Cochlear Implants↗

PubMed2000

Speech perception as a function of electrical stimulation rate: using the Nucleus 24 cochlear implant system.

OBJECTIVE: To investigate the effect of varying electrical stimulation rate on speech comprehension by cochlear implant users, while keeping the number of stimulated channels constant. DESIGN: Three average rates of electrical stimulation, 250, 807, and 1615 pulses per second per channel (pps/ch), were compared using a speech processing strategy that employed an electrode selection technique similar to that used in the Spectral Maxima Sound Processor strategy (McDermott, McKay, & Vandali, 1992; McDermott & Vandali, Reference Note 1; McKay, McDermott, Vandali, & Clark, 1991) and the Spectral Peak strategy (Skinner et al., 1994; Whitford et al., 1995). Speech perception tests with five users of the Nucleus 24 cochlear implant system were conducted over a 21-wk period. Subjects were given take-home experience with each rate condition. A repeated ABC evaluation protocol with alternating order was employed so as to account for learning effects and to minimize order effects. Perception of open-set monosyllabic words in quiet and open-set sentences at signal to noise ratios ranging from +20 to 0 dB, depending on the subject's ability, were tested. A comparative performance questionnaire was also administered. RESULTS: No statistical differences in group performance between the 250 and 807 pps/ch rates were observed in any of the speech perception tests. However, significantly poorer group performance was observed for the 1615 pps/ch rate for some tests due predominantly to the results of one subject. Analysis of individual scores showed considerable variation across subjects. For some subjects, one or more of the three rate conditions evaluated provided benefits on some speech perception tasks. The results of the comparative performance questionnaire indicated a preference for the 250 and 807 pps/ch rates over the 1615 pps/ch rate for most listening situations. CONCLUSIONS: For the speech processing strategy, implant system, and subjects evaluated in this study, the group results indicated that the use of electrical stimulation rates higher than 250 pps/ch (up to 1615 pps/ch) generally provided no significant improvement to speech comprehension. However, individual results indicated that perceptual benefits could be obtained by adjusting rate of stimulation optimally to suit each subject. Results from one subject, together with tinnitus problems arising from high-rate stimulation for another subject, indicated that high rates of stimulation may in fact be undesirable for some subjects.

Adult↗

PubMed1988

Unanswered questions concerning the indication for cochlear implant.

In a discussion of the function of cochlear implant (CI), the following criteria should be mentioned: (1) If possible, all deaf persons (including the prelingually deaf and children) should benefit from CI. (2) Since the number of patients with late deafness is doubtlessly decreasing with better prevention and medical care (elimination of ototoxic damage, decrease of iatrogenic deafness), the percentage distribution of the deaf will be displaced in favor of the prelingually deaf. At present, the ratio of cases of late deafness to those of prelingual deafness among our CI candidates is 1:3. (3) The objective of CI must be to provide the advantage of the procedure to children as early as possible. This means that under certain circumstances a technique that is as low in risks as possible and with a handy implement should already have been used in patients at the age of 3 to 4 years.

Adaptation, Psychological↗

PubMed1985

Absolute identification of electric pulse rates and electrode positions by cochlear implant patients.

In a single interval task, multichannel cochlear implant patients were asked to identify the members of a set of seven electric stimuli differing in electric pulse rate or electrode position. The perceptual sensitivity index (d') between successive stimuli in a stimulus set was calculated from the confusions among the seven stimuli. The results showed that the pulse rate above which the identification task became difficult varied from 200 to 600 pps from patient to patient. For the identification of the positions of seven bipolar electrode pairs, d' measures for stimulus sets differing in spatial separation or spatial extent were compared. Spatial separation is defined as the fixed distance between the two basal (or apical) electrodes of two successive bipolar electrode pairs in a stimulus set, while spatial extent is defined as the fixed distance between the apical and basal electrodes of each bipolar electrode pair in a stimulus set. The results showed that perceptual performance improved in an orderly way with spatial separation, but was not significantly affected by spatial extent.

Adult↗

PubMed1991

Cochlear implant flap necrosis: adjunct hyperbaric oxygen therapy for prevention of explantation.

The most common complication resulting from cochlear implant surgery involves the skin flap: scalp breakdown, flap necrosis, and implant exposure requiring explantation. A 5.4 percent flap complication rate has been reported with the C-shaped postauricular flap (anteriorly-based on the superficial temporal and occipital arteries) in contrast to a 0 percent flap complication rate with the Australian inverted U-flap (inferiorly-based on the occipital artery). The literature is scant concerning detailed management of flap necrosis in order to obviate cochlear implant removal. Presented is an illustrative case of full thickness C-shaped flap necrosis with resultant exposure of a Nucleus multichannel implant. Successful wound management required pre- and postoperative hyperbaric oxygen in conjunction with a transposition flap closure of the scalp defect. Cochlear explantation was not necessary and rehabilitation and implant function were excellent 18 months postoperatively.

Adult↗

PubMed1997

Effect of relative amplitude and formant transitions on perception of place of articulation by adult listeners with cochlear implants.

Previous studies have shown that manipulation of a particular frequency region of the consonantal portion of a syllable relative to the amplitude of the same frequency region in an adjacent vowel influences the perception of place of articulation. This manipulation has been called the relative amplitude cue. Earlier studies have examined the effect of relative amplitude and formant transition manipulations upon labeling place of articulation for fricatives and stop consonants in listeners with normal hearing. The current study sought to determine if (a) the relative amplitude cue is used by adult listeners wearing a cochlear implant to label place of articulation, and (b) adult listeners wearing a cochlear implant integrated the relative amplitude and formant transition information differently than listeners with normal hearing. Sixteen listeners participated in the study, 12 with normal hearing and 4 postlingually deafened adults wearing the Nucleus 22 electrode Mini Speech Processor implant with the multipeak processing strategy. The stimuli used were synthetic consonant-vowel (CV) syllables in which relative amplitude and formant transitions were manipulated. The two speech contrasts examined were the voiceless fricative contrast /s/-"sh" and the voiceless stop consonant contrast /p/-/t/. For each contrast, listeners were asked to label the consonant sound in the syllable from the two response alternatives. Results showed that (a) listeners wearing this implant could use relative amplitude to consistently label place of articulation, and (b) listeners with normal hearing integrated the relative amplitude and formant transition information more than listeners wearing a cochlear implant, who weighted the relative amplitude information as much as 13 times that of the transition information.

Adult↗

PubMed2000

Effects of the salience of pitch and periodicity information on the intelligibility of four-channel vocoded speech: implications for cochlear implants.

Recent simulations of continuous interleaved sampling (CIS) cochlear implant speech processors have used acoustic stimulation that provides only weak cues to pitch, periodicity, and aperiodicity, although these are regarded as important perceptual factors of speech. Four-channel vocoders simulating CIS processors have been constructed, in which the salience of speech-derived periodicity and pitch information was manipulated. The highest salience of pitch and periodicity was provided by an explicit encoding, using a pulse carrier following fundamental frequency for voiced speech, and a noise carrier during voiceless speech. Other processors included noise-excited vocoders with envelope cutoff frequencies of 32 and 400 Hz. The use of a pulse carrier following fundamental frequency gave substantially higher performance in identification of frequency glides than did vocoders using envelope-modulated noise carriers. The perception of consonant voicing information was improved by processors that preserved periodicity, and connected discourse tracking rates were slightly faster with noise carriers modulated by envelopes with a cutoff frequency of 400 Hz compared to 32 Hz. However, consonant and vowel identification, sentence intelligibility, and connected discourse tracking rates were generally similar through all of the processors. For these speech tasks, pitch and periodicity beyond the weak information available from 400 Hz envelope-modulated noise did not contribute substantially to performance.

Cochlear Implants↗

PubMedDate not supplied

Cortical activation in profoundly deaf patients during cochlear implant stimulation demonstrated by H2(15)O PET.

Cochlear implants (CIs) are used to provide sensations of sound to profoundly deaf patients. The performance of the CI is assessed mainly by the subjective reports of patients. The aim of this study was to look for objective cortical responses to the stimulation of the CI. Two postlingually and two prelingually deaf patients were investigated by positron emission tomography (PET) using 15O-labeled water (H2(15)O) to determine the regional cerebral blood flow (rCBF). Instead of quantifying rCBF in absolute terms, it was estimated by referring the regional tissue concentration of H2(15)O to the mean whole brain concentration. CI stimulation encoded from white noise and sequential words led to an increased rCBF in the primary and secondary (Wernicke) auditory cortex. Relative elevations of up to 33% were observed bilaterally, although they were higher contralateral to the CI. These results were obtained not only in the postlingually deaf patients but also in two patients who had never been able to hear. Thus, it could be demonstrated that PET measurements of cerebral H2(15)O distribution yield objective responses of the central auditory system during electrical stimulation by CIs in profoundly deaf patients.

Adult↗

PubMed2005

Mild hypothermia protects auditory function during cochlear implant surgery.

OBJECTIVE/HYPOTHESIS: Loss of auditory function after cochlear implant (CI) electrode insertion occurs in two stages in the laboratory rat. An immediate loss is followed by a progressive loss over 7 days. Similar stages of acute and progressive neuronal loss occur after trauma in the central nervous system where hypothermia has been shown to have a protective effect. We hypothesize that hypothermia has a similar protective effect against loss of auditory function caused by CI electrode insertion trauma. METHODS: Thirty rats underwent surgery in one cochlea; the contralateral ear was an unoperated control. In the normothermia group, CI electrode insertion trauma was generated with rectal temperature maintained at 37 degrees C throughout the experiment. In the mild hypothermia group, electrode trauma was generated with rectal temperature lowered to 34 degrees C. In the surgical control group, mock surgery was performed at 37 degrees C. Multiple frequency auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) testing of all ears was performed before surgery, immediately afterward, and on postoperative days 3, 5, and 7. RESULTS: Both ABR and DPOAE testing demonstrated partial loss of auditory function after electrode insertion trauma. However, the hypothermia group had significantly less functional loss in the immediate stage and no significant loss in the progressive stage. CONCLUSION: Mild hypothermia protects auditory function during CI electrode insertion.

Animals↗