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PubMed1988

Magnetic resonance imaging (MRI) and high resolution computertomography (HRCT) in cochlear implant candidates.

Cochlear implant candidates must be thoroughly tested for their suitability pre-operatively. Electrical and electrophysiological tests as well as a psychological assessment are of fundamental importance in the selection process. The implantation of an intracochlear electrode requires specific information about the anatomy of the petrous bone and the endocochlear space. Such information can be obtained by using high resolution computed tomography (HRCT) or magnetic resonance imaging (MRI) using a surface coil. Over three years 438 patients were evaluated in our clinic as possible implant candidates. Out of these candidates 251 were evaluated using HRCT and 123 using MRI. In 39 (15.5%) cases we found bony abnormalities of the petrous bone using HRCT scans. 17 (13.8%) of the cases evaluated with MRI had no complete fluid filled spaces in the cochlea. Three patients who where identified as having ossified cochleas were subsequently implanted with an extracochlear device. MRI and HRCT have proved to be fundamental tools in determining patients suitable for implantation of an intracochlear electrode array.

Cochlea↗
PubMed1999

Language development in children implanted with the CLARION cochlear implant.

This study examined the development of language skills in 23 prelingually, profoundly deaf children following implantation with the CLARION Multi-Strategy Cochlear Implant. Language skills were assessed with the Reynell Developmental Language Scales (RDLS) preoperatively with hearing aids, and compared to postoperative performance after 6 months of Clarion use. The RDLS was administered in each child's preferred mode of communication, either spoken English alone or simultaneous spoken and signed English. Significant improvements were observed in average age-equivalent scores over time, both for receptive and expressive skills, although the absolute language levels of the implanted children remained delayed relative to those of hearing peers of the same chronological age. The children's rate of language growth in the first 6 months of implant use also was calculated. The results from this analysis showed that the Clarion children, on average, progressed at a rate that exceeded that of normal-hearing children of the same language age. There was no significant difference between the language performance of children who used oral versus total communication.

Aging↗
PubMed1999

SAS-CIS preference study in postlingually deafened adults implanted with the CLARION cochlear implant.

This study examined the speech perception performance of 71 postlingually deafened adults implanted with the CLARION Multi-Strategy Cochlear Implant. After 3 months of implant use, one third of the patients (n = 23) preferred to use the Simultaneous Analog Stimulation (SAS) strategy, and two thirds of them (n = 48) chose to use the Continuous Interleaved Sampler (CIS) strategy. The mean CID sentence scores were similar for the SAS and CIS user groups at the 3-month postoperative interval. In contrast, the mean CNC word score of the SAS users was significantly higher than the mean score of the CIS users after 3 months of implant experience. Patients who preferred to use SAS demonstrated significantly shorter duration of deafness at time of implantation than did the CIS users, whereas the CIS users demonstrated significantly higher preoperative sentence recognition scores than the SAS users. The results suggested that access to a preferred processing strategy improved the overall group performance of postlingually deafened adults in the present study compared to the results of previous studies in which only the CIS strategy was available to most patients with the Clarion.

Choice Behavior↗
PubMed2006

Dual-electrode pitch discrimination with sequential interleaved stimulation by cochlear implant users.

Cochlear implant users may perceive intermediate place-pitches between those elicited by the individual electrodes when two electrodes are stimulated simultaneously or sequentially. This study examined pitch discrimination between adjacent electrodes using sequential dual-electrode stimulation in terms of the sensitivity index, d', which was obtained by adding d's from intermediate dual-electrode stimuli. Loudness was balanced for each tested pair and the intensities were roved. Twelve ears with the Nucleus 24 or Freedom implants demonstrated a wide range of d', from 0.7 to 9.6. "Virtual channels" can be implemented through nonsimultaneous stimulation, with comparable pitch discrimination to that observed with simultaneous stimulation.

Acoustic Stimulation↗
PubMed1989

Issues of candidate selection for a cochlear implant.

The cochlear implant has been successful in providing sound to deaf patients. A wide spectrum of results, from sound awareness to word understanding without lipreading, has been achieved. However, because of the unpredictable nature of the results, appropriate candidate selection is imperative. Medical and surgical criteria for treatment of adults and children are presented.

Age Factors↗
PubMed2000

Results and experience of 50 cochlear implant operations.

Cochlear implantation (CI) is a relatively new type of treatment that aims to re-establish hearing in deaf people. This paper reports on the results from CI operations on 34 adults and 17 children. All patients benefited from the treatment. The adults' communication with other people improved. Almost all patients use their implant 16 h a day and some of them are able to communicate by telephone. Among children the results show that the treatment is safe, as no complications have developed. Hearing and speech improved in all children, and thus also their ability to communicate. The results obtained are dependent on the individual patient's condition, the time of operation in relation to the development of deafness, and the type of CI used. CI treatment of deaf people may be considered to be one of the greatest advances in otology.

Adolescent↗
PubMed1999

Histories of cochlear implantation.

The cochlear implant, an electronic device by means of which some totally deaf people can be provided with a form of hearing, has been increasingly used since the early 1980s. The mass media have typically presented it as an example of the remarkable success of modern technological medicine. In France and The Netherlands, the countries on which this paper focuses, as in many others, deaf communities have rejected the technology. They have protested at its use with deaf children in particular. Rather than locating it in a history of medical progress, they have located it within a history of their own oppression. Each historical rendering is used to try to influence policy. The contest, however, is an unequal one.

Child↗
PubMed1990

What should be implemented in future cochlear implants?

Cochlear-implant performance can be improved by focusing on: 1) psychophysical studies to determine hearing limitations; 2) speech perception to suggest the most effective speech-processing strategies; 3) aural rehabilitation to effectively train patients to use the new electrical stimuli. Basic psychophysical studies have shown only weak correlations with speech perception. Perhaps more speech-like stimuli should be explored in psychophysical tasks. Studies on vowel and consonant recognition suggest enhancing all speech features, but particularly frication and place of articulation should help most patients. Probably the feature that would be the most beneficial to enhance is place of articulation, which is poorly coded even in the best patients. Empirical studies are needed to determine the ways in which these cues can be enhanced. Certain types of auditory training are likely to be beneficial, particularly when the signal is new, incomplete or distorted. However, much more research in aural rehabilitation is needed.

Cochlear Implants↗
PubMed1993

Comparison of two methods of data presentation for the electrical brainstem response in cochlear implant patients.

Cochlear implants have become an acceptable method for management of the deaf patient, adult and child alike. Since the advent of implants there has been much research into objective methods for setting electrode values. The most common method is the electrical auditory brainstem response (EABR). The result of EABR threshold measurement is frequently reported as an arbitrary stimulus level set by the manufacturer. However, there has been recent discussion of whether an arbitrary stimulus level is acceptable or if the results should be reported in absolute units, either charge or current, particularly when combined data are used. This report compares two methods of data presentation for the EABR, arbitrary stimulus level and absolute units measured in nanoCoulombs (nC). Data collected from a previous study were used in this comparison. All patients were fitted with the Nucleus multi-channel device and Mini Speech Processor. The correlation between stimulus level and log charge (nC) was 0.990 with a slope of 0.987 which suggests the method of data reporting does not alter EABR results materially when using the Nucleus device.

Adolescent↗
PubMed2004

Vestibular effects of cochlear implantation.

OBJECTIVES/HYPOTHESIS: Cochlear implantation (CI) carries with it the potential risk for vestibular system insult or stimulation with resultant dysfunction. As candidate profiles continue to evolve and with the recent development of bilateral CI, understanding the significance of this risk takes on an increasing importance. STUDY DESIGN: Between 1997 to 2001, a prospective observational study was carried out in a tertiary care medical center to assess the effects of unilateral CI on the vestibular system. METHODS: Assessment was performed using the dizziness handicap inventory (DHI), vestibulo-ocular reflex (VOR) testing using both alternate bithermal caloric irrigations (ENG) and rotational chair-generated sinusoidal harmonic accelerations (SHA), and computerized dynamic platform posturography (CDP) at preoperative, 1-month, 4-month, 1-year and 2-year postimplantation visits. CI was carried out without respect to the preoperative vestibular function test results. RESULTS: Specifically, 86 patients were entered into the study after informed consent. For the group as a whole, pair wise comparisons revealed few significant differences between preoperative and postoperative values for VOR testing (ENG and SHA) at any of the follow-up intervals. Likewise, DHI testing was also unchanged except for significant reductions (improvements) in the emotional subcategory scores at both the 4-month and 1-year intervals. CDP results demonstrated substantial improvements in postural sway in the vestibular conditions (5 and 6) as well as composite scores with the device "off" and "on" at the 1-month, 4-month, 1-year, and 2-year intervals. Device activation appeared to improve postural stability in some conditions. Excluding those patients with preoperative areflexic or hyporeflexic responses in the implanted ear (total [warm + cool] caloric response or=21 deg/s maximum slow phase velocity) in total caloric response were observed for 8 (29%) patients at the 4-month interval. These persisted throughout the study period. These changes were accompanied by significant low frequency phase changes on SHA testing confirming a VOR insult. Of interest, no significant changes were detected in the DHI or CDP, and there were no effects of age, sex, device manufacturer, or etiology of hearing loss (HL) for these patients. CONCLUSIONS: Unilateral CI rarely results in significant adverse effects on the vestibular system as measured by the DHI, ENG, SHA, and CDP. On the contrary, patients that underwent CI experienced significant improvements in the objective measures of postural stability as measured by CDP. Device activation in music appeared to have an additional positive effect on postural stability during CDP testing. Although VOR testing demonstrated some decreases in response, patients did not suffer from disabling vestibular effects following CI. The mechanism underlying these findings remains speculative. These findings should be considered in counseling patients about CI.

Adolescent↗
PubMed1999

[Study of surgical complications and technical failures (correction of technical defects) of cochlear implants].

INTRODUCTION: Cochlear implants (CI) have proved their clinical efficacy and have overcome a routine treatment for profound sensorineural impairment. In the present paper we review our CI program concerning surgical complications and equipment failures. MATERIAL AND METHODS: One-hundred and thirty-five patients (69 younger and 66 older than 14 years of age) are subjects of the study. They suffered from pre-lingual (86 cases) or post-lingual (49 cases) profound bilateral sensorineural hearing impairment, and all of them received a Mini Nucleus 22 CI in our CI program. We analyze minor and major surgical complications and also CI and external equipment failures. RESULTS: In 6.1% of the patients (8 cases) a surgical complication occurred, 3 of them flap-related complications. In 2 of these cases (1.54%) complications were major. Three patients (2.17%) developed a complete CI failure, while in 8 cases malfunction of one or more electrodes was detected. Cumulative survival of CI was 87 months, without significant differences related to age or gender. Cumulative survival of the processors was 78.6 months, without significant differences related to the type of processor (MSP or Spectra) or gender but related to the age. The microphone failed in 42.2% of the cases. CONCLUSIONS: The CI is a low-morbidity treatment with adequate characteristics of durability and reliability. Nevertheless, some of the external components remain quite vulnerable.

Adolescent↗
PubMed1996

[Indications for middle ear obliteration within the scope of cochlear implant management].

BACKGROUND: Cochlear implants have gained worldwide acceptance as a reliable method of rehabilitation of profoundly hearing-impaired patients. Due to thorough patient selection major postoperative complications rarely occur and are flap related in most cases. Deafness can develop during chronic suppurative otitis media, either coincidentally or secondary to the medical treatment; normally this condition is regarded as a contraindication for cochlear implantation. In cases with a mastoid cavity after surgical treatment for cholesteatoma, the electrode covered only by the epithelial lining will likely become exposed or extruded. Therefore we suggest the obliteration of the middle ear cleft with abdominal fat and the blindsac closure of the external ear canal before cochlear implantation in these conditions. PATIENTS: The average age of our 12 patients was 48 years, whereas the youngest was 2 1/2 years of age. Due to chronic inflammatory ear disease. 11 patients had a mastoid cavity on both ears. Eight patients had a cholesteatoma, the chronic bone destroying process in the temporal bone of two female patients was considered as a fibroinflammatory pseudotumor. The child had a congenital deafness in both ears with a Mondini dysplasia in CT scan. She had already developed two episodes of pneumococcal meningitis which was caused by a defect in the stapes footplate through which a liquor-filled cystic sac herniated in the middle ear. Because of a massive liquorrhoea after opening of the sac, we decided to obliterate the middle ear cleft after successful insertion of the electrode array. RESULTS: All active electrodes of 10 Nucleus implants (Cochlear) and two Clarion devices (Advanced Bionics Corp.) were successfully inserted in the cochlea of the 12 patients. After an average follow-up of 15 months, a temporary facial palsy in one patient and an insufficient closure of a retroauricular fistula over the mastoid cavity in two cases were observed as postoperative complications. One patient with a fibroinflammatory pseudotumor developed a massive inflammatory reaction in the implanted ear two months after cochlear implantation, which could not be controlled by conservative treatment. The implant had to be removed and local conditions settled after administration of immunosuppressive treatment with cyclophosphamide. The patient received a new implant seven months ago. CONCLUSIONS: Implantation of a foreign body in a potentially infected space which communicates intracranially means a surgical challenge which can be managed by obliteration of the middle ear after subtotal petrosectomy with abdominal wall fat combined with a reliable closure of the external ear canal. In case of massive inflammation we would prefer a two-stage procedure.

Adipose Tissue↗
PubMed2004

Localization ability with bimodal hearing aids and bilateral cochlear implants.

After successful cochlear implantation in one ear, some patients continue to use a hearing aid at the contralateral ear. They report an improved reception of speech, especially in noise, as well as a better perception of music when the hearing aid and cochlear implant are used in this bimodal combination. Some individuals in this bimodal patient group also report the impression of an improved localization ability. Similar experiences are reported by the group of bilateral cochlear implantees. In this study, a survey of 11 bimodally and 4 bilaterally equipped cochlear implant users was carried out to assess localization ability. Individuals in the bimodal implant group were all provided with the same type of hearing aid in the opposite ear, and subjects in the bilateral implant group used cochlear implants of the same manufacturer on each ear. Subjects adjusted the spot of a computer-controlled laser-pointer to the perceived direction of sound incidence in the frontal horizontal plane by rotating a trackball. Two subjects of the bimodal group who had substantial residual hearing showed localization ability in the bimodal configuration, whereas using each single device only the subject with better residual hearing was able to discriminate the side of sound origin. Five other subjects with more pronounced hearing loss displayed an ability for side discrimination through the use of bimodal aids, while four of them were already able to discriminate the side with a single device. Of the bilateral cochlear implant group one subject showed localization accuracy close to that of normal hearing subjects. This subject was also able to discriminate the side of sound origin using the first implanted device alone. The other three bilaterally equipped subjects showed limited localization ability using both devices. Among them one subject demonstrated a side-discrimination ability using only the first implanted device.

Adult↗
PubMed1996

Cochlear implantations in children.

Cochlear implant procedures are available for children who are diagnosed with severe hearing loss. Cochlear implants can restore children's perceptions of sound through the use of electronic devices. Perioperative nurses should be knowledgeable about all surgical aspects of cochlear implant procedures and be aware of the months of preparation before surgery and the lengthy rehabilitation afterward. This article discusses the historical development of the cochlear implant procedures, describes the hearing process, describes candidate selection, and discusses the perioperative care for a child receiving a cochlear implant in a case study presentation.

Child↗
PubMed1999

Age at implantation: its importance in pediatric cochlear implantation.

OBJECTIVE: To assess the influence of age at implantation on speech perception and speech intelligibility following pediatric cochlear implantation. STUDY DESIGN: A prospective study was undertaken on a consecutive group of 126 congenital and prelingually deaf children up to 4 years after implantation. The study group was confined to prelingually deaf children less than 7 years of age at the time of implantation. All had implantation with the same multichannel cochlear implant system. No child was lost to follow-up, and there were no exclusions from the study. METHODS: The Iowa Matrix Closed Set Sentence test, connected discourse tracking, categories of auditory performance, and speech intelligibility rating were used to assess the speech perception (closed and open set) and speech intelligibility of the children with implants. Regression analysis and Spearman rank correlation coefficients were used to assess the correlation between the outcome measures with age at implantation. The setting was a tertiary referral pediatric cochlear implant center in the United Kingdom. RESULTS: Age at implantation positively correlated with preimplantation assessment performance and with most of the outcome measures up to 24 months following implantation. However, at the 3-and 4-year intervals following implantation, age at implantation was found to be a strong negative predictor of all the outcomes studied (correlation coefficients ranging from -0.44 to -0.58, all statistically significant [P<.05]). CONCLUSIONS: The results of the present study provide strong evidence that prelingually deaf children should receive implants as early as possible to facilitate the later development of speech perception skills and speech intelligibility and thus maximize the health gain from the intervention. However, because of the wide variation in individual outcomes, age alone should not be used as a criterion to decide implant candidacy.

Age Factors↗
PubMed2001

Auditory learning and adaptation after cochlear implantation: a preliminary study of discrimination and labeling of vowel sounds by cochlear implant users.

This study examined two possible reasons underlying longitudinal increases in vowel identification by cochlear implant users: improved labeling of vowel sounds and improved electrode discrimination. The Multidimensional Phoneme Identification (MPI) model was used to obtain ceiling estimates of vowel identification for each subject, given his/her electrode discrimination skills. Vowel identification scores were initially lower than the ceiling estimates, but they gradually approached them over the first few months post-implant. Taken together, the present results suggest that improved labeling is the main mechanism explaining post-implant increases in vowel identification.

Adaptation, Psychological↗