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PubMed1993

A review of patients attending a preliminary cochlear implant assessment clinic.

The Cochlear Implant Programme at Manchester Royal Infirmary was established in 1988 and so far (January, 1992) 38 patients have been implanted with the Nucleus 22 channel intracochlear device and one with the Ineraid device. All patients who are referred for consideration for an implant are initially seen at a preliminary cochlear implant assessment clinic conducted by an ENT surgeon. One hundred and seventy three patients attended the initial outpatient screening clinic between 1987 and January 1992. Of these 112 patients (67.6 per cent) went on for further investigation regarding suitability for implantation. This paper details the aetiology and severity of deafness in these patients and explains how suitability for admission to the next stage of assessment was decided.

Adolescent↗

PubMed2003

Speech perception, localization, and lateralization with bilateral cochlear implants.

Five bilateral cochlear implant users were tested for their localization abilities and speech understanding in noise, for both monaural and binaural listening conditions. They also participated in lateralization tasks to assess the impact of variations in interaural time delays (ITDs) and interaural level differences (ILDs) for electrical pulse trains under direct computer control. The localization task used pink noise bursts presented from an eight-loudspeaker array spanning an arc of approximately 108 degrees in front of the listeners at ear level (0-degree elevation). Subjects showed large benefits from bilateral device use compared to either side alone. Typical root-mean-square (rms) averaged errors across all eight loudspeakers in the array were about 10 degrees for bilateral device use and ranged from 20 degrees to 60 degrees using either ear alone. Speech reception thresholds (SRTs) were measured for sentences presented from directly in front of the listeners (0 degrees) in spectrally matching speech-weighted noise at either 0 degrees, +90 degrees or -90 degrees for four subjects out of five tested who could perform the task. For noise to either side, bilateral device use showed a substantial benefit over unilateral device use when noise was ipsilateral to the unilateral device. This was primarily because of monaural head-shadow effects, which resulted in robust SRT improvements (P<0.001) of about 4 to 5 dB when ipsilateral and contralateral noise positions were compared. The additional benefit of using both ears compared to the shadowed ear (i.e., binaural unmasking) was only 1 or 2 dB and less robust (P = 0.04). Results from the lateralization studies showed consistently good sensitivity to ILDs; better than the smallest level adjustment available in the implants (0.17 dB) for some subjects. Sensitivity to ITDs was moderate on the other hand, typically of the order of 100 micros. ITD sensitivity deteriorated rapidly when stimulation rates for unmodulated pulse-trains increased above a few hundred Hz but at 800 pps showed sensitivity comparable to 50-pps pulse-trains when a 50-Hz modulation was applied. In our opinion, these results clearly demonstrate important benefits are available from bilateral implantation, both for localizing sounds (in quiet) and for listening in noise when signal and noise sources are spatially separated. The data do indicate, however, that effects of interaural timing cues are weaker than those from interaural level cues and according to our psychophysical findings rely on the availability of low-rate information below a few hundred Hz.

Adult↗

PubMed1993

Considerations of cochlear implant surgery.

Although cochlear implants have been reported to be easy to perform, some difficulties have been experienced in 4 of 21 operations. In order to make this surgery easier, the following points should be considered. Pre-operative CT and MRI must be performed in order to determine the condition of the cochlea. To determine the condition of the round window, exploratory tympanotomy is recommended in some cases. After insertion of the electrode in the cochlea, a radiograph should be taken during the operation to confirm that the electrode is correctly positioned.

Adolescent↗

PubMed2001

A new application for the sympathetic skin response: the evaluation of auditory thresholds in cochlear implant patients.

OBJECTIVES: Cochlear implants (CI) are now widely used in patients with profound sensorineural deafness. Determining threshold levels for each CI electrode is required during the initial postoperative tuning session. While behavioral testing is appropriate in post-lingually deafened patients, it may be really tricky in pre-lingually deafened children. CI stimulation is responsible for auditory perception and logically induces brainstem reticular formation arousal which can be studied by sympathetic skin response (SSR). METHODS: Thirteen patients (aged 3-70 years) implanted with an MXM Digisonic((R)) were postoperatively studied. SSR as well as behavioral thresholds were recorded after electrical stimulation of CI electrodes at various intensities. RESULTS: SSR could be recorded in all patients including the 6 studied children. There was a strong correlation between SSR threshold and subjective auditory threshold (r=0.93). CONCLUSIONS: The present data indicate that SSR could have a clinical application as a routine test in postoperative fitting procedures of CIs especially in pre-lingually deafened children.

Adult↗

PubMed1990

Cochlear implant in Hong Kong Cantonese.

Cochlear implant surgery was performed in four Cantonese-speaking postlingually deaf Chinese adults, using the House/3M single channel device. This article outlines the methodology, including preoperative assessment and postoperative rehabilitation; and explains the necessary modifications in speech and audiologic work-up in Cantonese-speaking patients. Salient features of Cantonese phonetics, especially its tonal characteristics, are described. The findings of the study are presented. The results of the cochlear implant would suggest a performance superior to that of the hearing aid. Furthermore, the cochlear implant is able to detect tonal cues. This quality of the cochlear implant may prove to be a valuable asset to a tonal language-speaking cochlear implantee.

Adult↗

PubMed1999

The CLARION Multi-Strategy Cochlear Implant.

The Clarion cochlear implant is the result of many years of research and development, first at the University of California, San Francisco and the Research Triangle Institute of North Carolina, and then at Advanced Bionics Corporation in Sylmar, California. Approved by the US Food and Drug Administration after carefully monitored investigational clinical trials in both the adult and pediatric populations, it has now been implanted in approximately 3,000 patients worldwide. A fully flexible, programmable system, the Clarion offers multiple strategies and options in speech processing. The coupling mode, the stimulating waveform, and the temporal pattern of stimulation can be selected to allow each patient an opportunity to be fitted with the strategy that offers the highest level of performance. This paper describes the current status of the Clarion system. However, Clarion development has been a dynamic process, and from its initial introduction in 1991, the system has been modified and continually improved. The process of improvement and advancement is ongoing. New speech processing strategies and hardware developments are briefly summarized at the conclusion of this paper.

Cochlear Implants↗

PubMed1989

[Auditory and communication learning in patients with cochlear implants].

Nowadays the cochlear implant (CI) offers a new method of hearing, especially for deaf patients who do not benefit from conventional hearing aids. However, it may be difficult to get used to this kind of hearing advice. CI users have special problems in interpreting strange acoustic sensations and relating them to auditory features of language and noise they knew before the onset of deafness. An interdisciplinary approach is very important for rehabilitation. Beside otological examination and the surgical implantation, audiological assessment is needed for the correct adjustment of the speech processor and for measurement of performance. Also auditory management and counselling of deaf patients is an important part of CI rehabilitation. A learning programme in hearing and communicating ("hearing training") is offered to CI users that takes account of different linguistic levels. Auditory learning by the use of CI is based on different abilities of the deaf patient, of which the most important are speech skills and learning capacity. Although success rates vary, it certainly improves speech intelligibility during lip reading, communication behaviour, and recognition of environmental noise. The latter ability improves orientation in the acoustic surroundings. CI rehabilitation may improve the psychosocial attitude of the deaf.

Cochlear Implants↗

PubMed1986

The Vienna cochlear implant program.

The cochlear implant program in Vienna has now gathered 160 patient years of experience with 25 patients who have received an extracochlear implant prosthesis and 31 patients who have received an intracochlear implant prosthesis. The sound processor avoids the transformation of speech into pulses and provides a processed analog broad-band stimulation signal. Approximately one half of the patients are prelingually deaf. The selection criteria include electrical promontory stimulation and acoustic and electrical brain-stem audiometry. The rehabilitation program consisting of counseling, communication training, and auditory training is considered an important part of the program. The results are assessed using the Vienna Auditory Test battery. Sixty per cent of the postlingually deafened patients achieve some open-set speech understanding without lip-reading. Sixty-five per cent of the users show a substantial improvement in aided speech understanding versus lip-reading alone.

Audiometry, Evoked Response↗

PubMed2005

Effects of stimulation rate, mode and level on modulation detection by cochlear implant users.

In cochlear implant (CI) patients, temporal processing is often poorest at low listening levels, making perception difficult for low-amplitude temporal cues that are important for consonant recognition and/or speech perception in noise. It remains unclear how speech processor parameters such as stimulation rate and stimulation mode may affect temporal processing, especially at low listening levels. The present study investigated the effects of these parameters on modulation detection by six CI users. Modulation detection thresholds (MDTs) were measured as functions of stimulation rate, mode, and level. Results show that for all stimulation rate and mode conditions, modulation sensitivity was poorest at quiet listening levels, consistent with results from previous studies. MDTs were better with the lower stimulation rate, especially for quiet-to-medium listening levels. Stimulation mode had no significant effect on MDTs. These results suggest that, although high stimulation rates may better encode temporal information and widen the electrode dynamic range, CI patients may not be able to access these enhanced temporal cues, especially at the lower portions of the dynamic range. Lower stimulation rates may provide better recognition of weak acoustic envelope information.

Acoustic Stimulation↗

PubMed2006

Effects of directional microphone and adaptive multichannel noise reduction algorithm on cochlear implant performance.

Although cochlear implant (CI) users have enjoyed good speech recognition in quiet, they still have difficulties understanding speech in noise. We conducted three experiments to determine whether a directional microphone and an adaptive multichannel noise reduction algorithm could enhance CI performance in noise and whether Speech Transmission Index (STI) can be used to predict CI performance in various acoustic and signal processing conditions. In Experiment I, CI users listened to speech in noise processed by 4 hearing aid settings: omni-directional microphone, omni-directional microphone plus noise reduction, directional microphone, and directional microphone plus noise reduction. The directional microphone significantly improved speech recognition in noise. Both directional microphone and noise reduction algorithm improved overall preference. In Experiment II, normal hearing individuals listened to the recorded speech produced by 4- or 8-channel CI simulations. The 8-channel simulation yielded similar speech recognition results as in Experiment I, whereas the 4-channel simulation produced no significant difference among the 4 settings. In Experiment III, we examined the relationship between STIs and speech recognition. The results suggested that STI could predict actual and simulated CI speech intelligibility with acoustic degradation and the directional microphone, but not the noise reduction algorithm. Implications for intelligibility enhancement are discussed.

Adult↗

PubMed2006

[Use of intraoperative round window electrocochleography for assessment of cochlear implantation safety].

OBJECTIVE: To objectively evaluate whether cochlear implantation surgery made damage to cochlear basal membrane or not through analyzing the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. METHOD: Round window electrocochleography was performed on 40 cases with profound sensorineural deafness under general anesthesia in the standard operating room in order to analyze the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. RESULT: Among the 40 cases, thresholds of cochlear microphonic (CM) before and after inserting electrode during cochlear implantation surgery were similar in 39 cases. The thresholds of cochlear microphonic (CM) after inserting electrode decreased about 5 dB at certain frequency. The thresholds of cochlear microphonic (CM) after inserting electrode increased 20-50 dB in only one case. There was a sense of resistance in implanting the electrodes in this patient. CONCLUSION: Use of round window electrocochleography may objectively evaluate whether cochlear implantation surgery make damage to cochlear basal membrane or not.

Adolescent↗

PubMed2004

Speech, language, and reading skills after early cochlear implantation.

OBJECTIVE: To examine whether age at cochlear implantation or duration of implant use is associated with speech, language, and reading skills exhibited at age 8 to 9 years in children who underwent implantation by age 5 years. DESIGN: Performance outcomes in speech perception, speech production, language, and reading were examined in terms of the age at which children first received a cochlear implant (2, 3, or 4 years), the age they received an updated (Spectra) processor, and the duration of use of an implant and an updated processor. SETTING: Data collection was conducted at summer research camps held over 4 consecutive years to maximize the number of children available at a specific age (8-9 years). Children were tested individually by experienced examiners, and their parents and therapists provided background and educational history information. PARTICIPANTS: A total of 181 children from 33 different states and 5 Canadian provinces who received a cochlear implant by age 5 years were tested. A subsample of 133 children with performance IQ scores of 80 or greater and onset of deafness at birth were selected for the age-at-implantation analysis. Another subsample of 39 children with deafness acquired by age 3 years was also examined. OUTCOME MEASURES: A battery of tests of speech perception, speech production, language, and reading was administered to each child and reduced to a single factor score for each skill. RESULTS: Correlation coefficients between age at implantation and duration of use did not reach significance for any of the outcome skills measured. Age at which the updated speech processor (Spectra) was fitted was significantly related to speech production outcome (earlier use of an updated processor was associated with greater speech intelligibility) but not to any other skill area. However, more of the children who underwent implantation at age 2 years (43%) achieved combined speech and language skills commensurate with their age-matched peers with normal hearing than did children who underwent implantation at age 4 years (16%). Furthermore, normal speech and language skills were documented in 80% of children who lost hearing after birth and who underwent implantation within a year of onset of deafness. CONCLUSIONS: For children who receive a cochlear implant between the ages of 2 and 4 years, early cochlear implantation does not ensure better speech perception, speech production, language, or reading skills. However, greater speech and language proficiency may be expected from children who exhibit normal hearing for even a brief period after birth and receive a cochlear implant shortly after losing their hearing. Further research examining the benefits of cochlear implantation before age 2 years will help families and clinicians better understand the time-sensitive nature of the decision to conduct cochlear implant surgery.

Age Factors↗

PubMed2001

[Use X-ray or CR to evaluate the operation result of the cochlear implant].

OBJECTIVE: To evaluate the cochlear implant operation by the use of X-ray or CR. METHOD: There are 15 ears 15 cases which were completed the cochlear implant operation, after operation the implant electrode array was shown by the use of X-ray or CR. RESULT: The shape and station of those were normal, average insered depth was 23.05 mm, come up to provide standard. CONCLUSION: It was an economic, convenient, objective and worthy method to evaluate the cochlear implant.

Adolescent↗

PubMed2005

Reliability of cochlear implants.

BACKGROUND: The long-term reliability of cochlear implants over time is an important issue for patients and cochlear implant teams. The calculation of cumulative survival rates including all hard failures of cochlear implants is suitable to report objectively about cochlear implant reliability. METHODS: This is a report of 192 cochlear implants from different manufacturers in adults (n = 58) and children (n = 134). RESULTS: The overall cumulative implant survival rate was 91.7% for a period of 11 years. The main reasons for hard failures were design errors of the products and direct or indirect trauma to the cochlea implant site (especially in children) with consecutive breaks of the implant body or electrodes. CONCLUSIONS: To improve our knowledge about reliability of cochlear implants more studies on cumulative long time survival of cochlear implants are needed, where functional failures and complications for whatever reason (design, mechanical, electronic, medical) are included. Cochlear implant reliability data should be considered during the choice of an implant for each individual patient.

Adult↗

PubMed2006

Recognition of simulated telephone speech by cochlear implant users.

PURPOSE: To evaluate cochlear implant users' understanding of telephone speech. METHOD: Telephone speech was simulated by band-limiting broadband speech stimuli. Multitalker vowel, consonant, and sentence recognition was measured for both simulated telephone speech and broadband speech in 10 postlingually deafened adult cochlear implant users. The study was approved by the St. Vincent's Hospital institutional review board, and signed, informed consent was obtained from all participants. RESULTS: There was no significant difference in vowel recognition scores between broadband and telephone speech. However, mean consonant and sentence recognition scores were significantly poorer with telephone speech. CONCLUSIONS: The limited telephone bandwidth significantly reduced cochlear implant users' understanding of telephone speech. The effect of band-limited speech was highly variable, suggesting that the contribution of high-frequency information to speech recognition varied significantly among the cochlear implant users.

Adult↗

PubMedDate not supplied

Development of language and speech perception in congenitally, profoundly deaf children as a function of age at cochlear implantation.

Like any other surgery requiring anesthesia, cochlear implantation in the first few years of life carries potential risks, which makes it important to assess the potential benefits. This study introduces a new method to assess the effect of age at implantation on cochlear implant outcomes: developmental trajectory analysis (DTA). DTA compares curves representing change in an outcome measure over time (i.e. developmental trajectories) for two groups of children that differ along a potentially important independent variable (e.g. age at intervention). This method was used to compare language development and speech perception outcomes in children who received cochlear implants in the second, third or fourth year of life. Within this range of age at implantation, it was found that implantation before the age of 2 resulted in speech perception and language advantages that were significant both from a statistical and a practical point of view. Additionally, the present results are consistent with the existence of a 'sensitive period' for language development, a gradual decline in language acquisition skills as a function of age.

Age Factors↗

PubMed1976

The cochlear implant; basic principles.

In recent years the cochlear implant has been a subject of much discussion and controversy. The clinician has often been confused by the conflicting reports of success and failure. In this paper the development of the cochlear implant is reviewed and its present status summarized. It is hoped that the clinician may thereby gain an understanding of this device so that he can better evaluate its present and future status. Selection of Patients for Cochlear Implantation. The cochlear implant will benefit only those patients with hair cell loss who have remaining viable auditory neurons. In order to determine whether viable neurons remain, an electric current is passed through a small needle which is place into the promontory through the tympanic membrane. If patients experience an auditory sensation as a result of this electrical stimulation, it is felt that they are suitable candidates for a cochlear implant. Feasibility of Long-Term VIIIth Nerve Stimulation. Many questions have been raised regarding the feasibility of long-term stimulation of the auditory nerve. The first question raised was whether the auditory nerve would survive severe hair cell degeneration. Studies have shown that in most cases at least a few auditory neurons remain. The next question was whether the cochlear implant itself would destroy the remaining auditory neurons. Preliminary studies have shown that the nerve will survive the placement of electrodes both into the modiolus and the scala tympani. Several electrode materials and insulation have been found to be well tolerated, and there has been minimal damage from thermal or electrolytic processes; therefore, it appears feasible to stimulate the auditory nerve over a long period. Information Transfer by Electrical Stimulation. Single-channel stimulation produces only periodicity pitch, and information transfer is insufficient for speech discrimination. Experience to date indicates that it will be possible to produce both place and volley pitch by electrical stimulation with multiple electrodes in the scala tympani. These findings give promise for the feasibility of producing a device which will transfer sufficient information to produce speech discrimination. Present Status of the Cochlear Implant. To the present time 15 patients have been implanted with a unipolar electrode under the direction of the Ear Research Institute. These patients have all benefited from their devices. They are able to perceive background sounds and receive a cadence or rhythm to speech which makes the device helpful in lipreading. None of the patients have developed significant speech discrimination.

Auditory Cortex↗

PubMed1993

Video analysis: a method of assessing changes in preverbal and early linguistic communication after cochlear implantation.

As the age of cochlear implantation in children decreases, there is an increasing need for methods to monitor the preverbal and early linguistic development of children fitted with these devices. One method that has been used successfully to monitor children wearing acoustic amplifying hearing aids entails the video recording over time of child-adult interactions in a conversational setting, and the subsequent methodical analysis of various aspects of the interaction. These aspects include eye contact, turn taking, autonomy, and auditory processing. The same method has been applied to children wearing the Nucleus 22-electrode cochlear implant system. An overview is given of the video analysis results for a group of 10 children studied from a period before implantation up to one year postimplantation. The results illustrate group changes in the various measures due to the provision of auditory information by the cochlear implant, plus the scatter of individual data. It is concluded that early indications of progress over time generally predict the level of functioning achieved at 12 months postimplantation. The method provides essential objective information, which enables discrete changes in behavior to be monitored realistically. Two case studies are presented to illustrate the application of the video analysis method to obtain information for clinical management of children with cochlear implants.

Child↗