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PubMed2001

Emphasis of short-duration acoustic speech cues for cochlear implant users.

A new speech-coding strategy for cochlear implant users, called the transient emphasis spectral maxima (TESM), was developed to aid perception of short-duration transient cues in speech. Speech-perception scores using the TESM strategy were compared to scores using the spectral maxima sound processor (SMSP) strategy in a group of eight adult users of the Nucleus 22 cochlear implant system. Significant improvements in mean speech-perception scores for the group were obtained on CNC open-set monosyllabic word tests in quiet (SMSP: 53.6% TESM: 61.3%, p<0.001), and on MUSL open-set sentence tests in multitalker noise (SMSP: 64.9% TESM: 70.6%, p<0.001). Significant increases were also shown for consonant scores in the word test (SMSP: 75.1% TESM: 80.6%, p<0.001) and for vowel scores in the word test (SMSP: 83.1% TESM: 85.7%, p<0.05). Analysis of consonant perception results from the CNC word tests showed that perception of nasal, stop, and fricative consonant discrimination was most improved. Information transmission analysis indicated that place of articulation was most improved, although improvements were also evident for manner of articulation. The increases in discrimination were shown to be related to improved coding of short-duration acoustic cues, particularly those of low intensity.

Adult↗

PubMed2006

Using assessment of higher brain functions of children with GJB2-associated deafness and cochlear implants as a procedure to evaluate language development.

OBJECTIVE: While investigators have reported that patients with GJB2-associated deafness and cochlear implants have preferable language development, the mechanisms of this phenomenon remains unknown. The goal of the present study was to assess higher brain functions of patients with GJB2-related and GJB2-unrelated deafness as a method of evaluating language development. METHODS: Eight children with cochlear implants were subjected to genetic testing for GJB2 and underwent the Raven colored progressive matrices test, Rey's auditory verbal learning test, Rey's complex figure test, the standardized language test for aphasia, the picture vocabulary test, and the standardized comprehension test for abstract words. RESULTS: Three children were diagnosed with GJB2-related deafness, and five children were diagnosed with GJB2-unrelated deafness. All three GJB2-related cases demonstrated normal range higher brain functions and fair language development. By contrast, one GJB2-unrelated case showed a semantic disorder, another demonstrated a visual cognitive disorder with dyslexia, and another had attention deficit-hyperactivity disorder. CONCLUSIONS: Children with GJB2-unrelated deafness showed a high frequency of heterogeneous disorders that can affect proper language development. This difference between children with GJB2-related and GJB2-unrelated deafness may account for the improved language development in children with GJB2-related deafness and cochlear implants. Further, genetic diagnosis of the non-syndromic hearing loss represents a useful tool for the preoperative prediction of outcomes following a cochlear implant procedure.

Audiometry↗

PubMed2004

Semilongitudinal and axial CT planes in assessing cochlear patency in cochlear implant candidates.

OBJECTIVE: To investigate how cochlear patency as seen on computed tomography (CT), using axial plus semilongitudinal planes, is correlated with findings at surgery in cochlear implant patients. METHODS: Pre-operative CT scans of 45 patients were reviewed by three, independent observers. They classified the cochlear patency and recorded the location of any suspected decreased patency. The results were compared with the findings noted during surgery. RESULTS: In nine patients a decreased cochlear patency was found at surgery. The sensitivity and specificity of CT assessment were, respectively, 56-33-11% and 100-86-94%. The interobserver reproducibility is reflected in a mean kappa of 0.46. The sensitivity increased when only patients suffering from post-meningitic deafness were considered. CONCLUSION: Our study suggests that CT scans can be useful in assessing cochlear patency, especially in patients with post-meningitic deafness. This good performance might be explained by the combined use of scans in semilongitudinal and axial planes.

Adult↗

PubMed2006

Multichannel cochlear implants: relation of histopathology to performance.

OBJECTIVES: To determine the relationship of surviving neural elements to auditory function in multichannel cochlear implant temporal bones. STUDY DESIGN: Case series of all 14 existing multichannel cochlear implants in our temporal bone collection. METHODS: Devices included Nucleus 22 (n = 11), Nucleus 24 (n = 1), Ineraid (n = 1), and Clarion (n = 1). Morphologic evaluation of structural elements including spiral ligament, stria vascularis, hair cells, peripheral processes, and spiral ganglion cells was performed. Clinical performance data were obtained from patient charts. For eight patients, nonimplanted contralateral temporal bones were available and paired comparisons were made. RESULTS: Despite frequent absence of hair cells and peripheral processes, all bones had at least some remaining spiral ganglion cells. Percent of normal remaining structures were unrelated to auditory performance with the implant for any of the structural elements. Ganglion cell count in segment III showed significant negative correlations to speech discrimination scores for words and sentences (Rhos = -.687 and -.661, P < or = .03 and .04) as did segment IV and total ganglion cell count with word score (Rhos = -.632 and -.638; P < or = .05). Spiral ganglion cell survival did not differ between implanted and nonimplanted ears, with the exception of segment I, which had fewer cells in the implanted ear (P < or = .028). CONCLUSIONS: Performance variability of cochlear implants cannot be explained on the basis of cochlear neuronal survival. Although hair cells and peripheral processes were frequently absent or greatly diminished from normal, all subjects had at least some spiral ganglion cells. And, in this series, there was an inverse relationship between survival of ganglion cells and performance.

Adult↗

PubMedDate not supplied

MR compatibility of Med EL cochlear implants: clinical testing at 1.0 T.

PURPOSE: Our aim was to evaluate the MR compatibility of Med EL cochlear implants by performing in vitro and in vivo tests. METHOD: All experiments were done on a 1.0 T machine. Potential movement of the cochlear electrode relative to a scale was recorded. Potential dislodgment of the magnetic receiver coil was evaluated with the coil fixed to the retroauricular skin of a volunteer. Temperature changes were measured with temperature sensors fixed to the electrode, performing standard MR sequences. In 11 patients, MRI of the brain was performed 1 day before explantation of the devices using standard MR sequences. Testing of the auditory abilities was done before and after the examination. All explanted devices were assessed for function. RESULTS: There was no detectable movement of the electrode or the receiver coil nor any temperature change. There were no adverse events for the patients. All 11 explanted cochlear implants retained their function. CONCLUSION: Med EL cochlear implants are not a firm contraindication for MRI.

Artifacts↗

PubMed1984

Speech processing studies using an acoustic model of a multiple-channel cochlear implant.

The speech perception of two multiple-channel cochlear implant patients was compared with that of three normally hearing listeners using an acoustic model of the implant for 22 different speech tests. The tests used included a minimal auditory capabilities battery, both closed-set and open-set word and sentence tests, speech tracking and a 12-consonant confusion study using nonsense syllables. The acoustic model represented electrical current pulses by bursts of noise and the effects of different electrodes were represented by using bandpass filters with different center frequencies. All subjects used a speech processor that coded the fundamental voicing frequency of speech as a pulse rate and the second formant frequency of speech as the electrode position in the cochlea, or the center frequency of the bandpass filter. Very good agreement was found for the two groups of subjects, indicating that the acoustic model is a useful tool for the development and evaluation of alternative cochlear implant speech processing strategies.

Aged↗

PubMed2005

Health-related quality of life of Austrian children and adolescents with cochlear implants.

BACKGROUND AND OBJECTIVE: As shown by many studies, deaf children benefit considerably by cochlear implants (CI), concerning oral language and integration in mainstream schools. This had lead to the general view of a good quality of life of these children. Unfortunately so far nearly no studies on quality of life, and specially no studies on health-related quality of life (HRQoL) of children with cochlear implants, have been published. The present study with the objective for first, initial information on health-related quality of life of Austrian pupils with cochlear implants is a first step to fill this gap. METHODS: Forty-four Austrian pupils, out of 65 candidates, age 8-16, with a hearing experience of at least 3 years with implants, and their parents were surveyed in the CI Center, Salzburg (cross sectional study). Basic medical and audiological data were available for all pupils. Because of reading comprehension difficulties 15 pupils were excluded. Parents and children were surveyed with the KINDLr, a generic instrument for health-related quality of life of children and adolescents. Main outcome measures were the HRQoL-total scores (mean, transformed to 100, standard deviation). In addition, 95% confidence intervals, effect sizes, t scores (one- and two-sided t-tests), rank order correlations and coefficients of determination were calculated. RESULTS: The HRQoL-total score of the children with CI (n=18), age 8-12 was below the standard for hearing children (P<0.001). It differed from the total score of the parent rating (P<0.0001). The difference between the parent ratings of non-excluded and of excluded children (n=12) was not significant. The total score of the adolescents (n=11), age 13-16 was within the norm, with no significant difference between adolescent and parents. The total scores correlate with parent-child agreement in the ratings, with outcomes of audiological speech tests, length of time of deafness, and age at implantation. CONCLUSIONS: Children with CI experience a lower health-related quality of life, compared to hearing children, with a low parent-child agreement. The findings of this study point to a normal subjective health of adolescents with CI.

Adolescent↗

PubMed2006

Asymmetric pulses in cochlear implants: effects of pulse shape, polarity, and rate.

Existing cochlear implants stimulate the auditory nerve with trains of symmetric biphasic (BP) pulses. Recent data have shown that modifying the pulse shape, while maintaining charge balance, may be beneficial in terms of reducing power consumption, increasing dynamic range, and limiting channel interactions. We measured thresholds and most comfortable levels (MCLs) for various 99-pulses-per-second (pps) stimuli. "Pseudomonophasic (PS)" pulses consist of a brief phase of one polarity followed immediately by a longer and lower-amplitude phase of the opposite polarity. We focused on a novel variant of PS pulses, termed the "delayed pseudomonophasic (DPS)" stimulus, in which the longer phase is presented midway between the short phases of two consecutive pulses. DPS pulse trains produced thresholds that were more than 10 dB lower than those obtained with BP pulses. This reduction was much greater than the 0- to 3-dB drop obtained with PS pulses and was still more than 6 dB when a pulse rate of 892 pps was used. A study of the relative contributions of the two phases of DPS suggested that the short, high-amplitude phase dominated the perceived loudness. This study showed major threshold and MCL reductions using a DPS stimulus compared to the widely used BP stimulus. These reductions, which were predicted by a simple linear filter model, might lead to considerable power savings if implemented in a cochlear implant speech processor.

Adult↗

PubMed2006

Surgical results of cochlear implantation in malformed cochlea.

OBJECTIVE: To report the surgical aspects of cochlear implantation in malformed cochlea. SETTING: Tertiary care center. STUDY DESIGN: Retrospective case review. METHODS: Between November 1997 and October 2004, 20 patients with inner ear malformations were implanted in our department. The age range was between 2 and 37 years (average, 8.8 yr). The anomalies were classified according to Sennaroglu and Saatci classification. There were two patients with common cavity deformity, four cases of incomplete partition (IP) type I (cystic cochleovestibular malformation), four cases of IP type II (classical Mondini's deformity), nine patients with large vestibular aqueduct (LVA) syndrome, and one patient with X-linked deafness. RESULTS: Standard transmastoid facial recess approach was used in 17 patients (three patients with IP I, four patients with IP II, and nine patients with LVA syndrome). In the remaining patient with IP I, because of the dehiscent and anteriorly located facial nerve, the surgical approach had to be modified, and an anteroposterior approach was used. After elevating the tympanomeatal flap, the electrode was inserted through the ear canal and then transferred to the mastoid through a full-length cut produced in the ear canal. The flap then returned to its place. In the patients with common cavity deformity, the electrode was inserted by the transmastoid labyrinthotomy approach. Facial nerve had an abnormal course in four patients, but no patient had facial weakness postoperatively. Cerebrospinal fluid gusher was encountered in four patients, whereas oozing was present in five patients. It seems that a slightly larger cochleostomy may reduce postoperative rhinorrhea. The patient with common cavity deformity showed abnormal vestibular stimulation which decreased and was totally abolished during a 3-month period. CONCLUSION: Based on these findings, cochlear implantation is surgically feasible in patients with common cavity, IP types I and II, and LVA. The surgeon should be ready to make modifications in the surgical approach because of the abnormal course of the facial nerve and be ready to produce special precautions to cerebrospinal fluid gusher.

Adolescent↗

PubMedDate not supplied

[Long-latency auditory evoked potentials in cochlear implants].

Cortical evoked potentials were evaluated in patients with cochlear implants. In a group of 8 adults of different ages, the lingual state before implantation and during rehabilitation were evaluated. Using cortical evoked potentials, the results of the P300 wave in response to two tones, one frequent (1,000 Hz) and the other infrequent (2,000 Hz), presented at 70 and 80 dB HL were studied. Results were analyzed and compared in relation to locutive state, rehabilitation stage, and intensity of stimulus. Absolute latencies did not differ significantly. However, latency values in relation to reaction time were significantly longer in prelingual than in postlingual patients (p < 0.05, Student < > test). The results confirmed the normality of central cognitive processes in patients with cochlear implants in objective assessment of P300 latency. The results suggest differences between prelingual and postlingual patients in relation to central signal processing.

Acoustic Stimulation↗

PubMed2004

Searching for cochlear implant information on the internet maze: implications for parents and professionals.

The present study has three purposes: (a) to determine who disseminates information on cochlear implants on the Web; (b) to describe a representative sample of Web sites that disseminate information on cochlear implants, with a focus on the content topics and their relevance to parents of deaf children; and (c) to discuss the practical issues of Web-based information and its implications for professionals working with parents of deaf children. Using the terms "cochlear implants" and "children," the first 10 sites generated by the four most popular search engines (Google, Yahoo, Microsoft's MSN, and America Online) at two points in time were selected for analysis, resulting in a sample of 31 Web sites. The majority of Web sites represented medically oriented academic departments and government organizations, although a wide variety of other sources containing information about cochlear implants were also located. Qualitative analysis revealed that the content tended to fall into eight categories; however, the important issues of educational concerns, habilitation following surgery, and communication methods were either addressed minimally or neglected completely. Using analytical tools that had been developed to evaluate "user friendliness" in other domains, each Web site was assessed for its stability, service/design features and ease of use. In general, wide variability was noted across the Web sites for each of these factors. The strong recommendation is made that professionals understand and enhance their knowledge of both the advantages and limitations of incorporating the new technology into their work with parents.

Cochlear Implants↗

PubMed1998

Ethics of cochlear implantation in young children: a review and reply from a Deaf-World perspective.

This article examines ethical dilemmas related to cochlear implant surgery in children. These dilemmas arise from the existence of a linguistic and cultural minority called the Deaf World. Organizations of culturally Deaf adults in the United States and abroad, as well as the World Federation of the Deaf, have, on ethical grounds, strongly criticized the practice of cochlear implant surgery in children. Three ethical dilemmas are examined. (1) The surgery is of unproven value for the main significant benefit sought, language acquisition, whereas the psychological, social, and linguistic risks have not been assessed. Thus the surgery appears to be innovative, but innovative surgery on children is ethically problematic. (2) It is now widely recognized that the signed languages of the world are full-fledged natural languages, and the communities that speak those languages have distinct social organizations and cultures. Deaf culture values lead to a different assessment of pediatric cochlear implant surgery than do mainstream (hearing) values, and both sets of values have standing. (3) The fields of otology and audiology want to provide cochlear implants to Deaf children but also, their leaders say, want to protect Deaf culture; those appear to be conflicting goals in principle because, if there were perfect implants, the ranks of the Deaf World would diminish.

Adult↗

PubMed1996

Acoustic and articulatory measures of sibilant production with and without auditory feedback from a cochlear implant.

The articulator positions of a subject with a cochlear implant were measured with an electromagnetic midsagittal articulometer (EMMA) system with and without auditory feedback available to the subject via his implant. Acoustic analysis of sibilant productions included specific measures of their spectral properties as well as the F3 formant amplitude. More general postural characteristics of the utterances, such as speech rate and sound level, were measured as well. Because of the mechanical and aerodynamic interdependence of the articulators, the postural variables must be considered before attributing speech improvement to the selective correction of a phonemic target with the use of auditory feedback. The tongue blade position was related to the shape and central tendency of the /integral of/ spectra; however, changes in the spectral contrast between /s/ and /integral of/ were not related to changes in the more general postural variables of rate and sound level. These findings suggest that the cochlear implant is providing this subject with important auditory cues that he can use to monitor his speech and maintain the phonemic contrast between /s/ and /integral of/.

Adult↗

PubMed2001

Introducing music as a means of habilitation for children with cochlear implants.

OBJECTIVE: To investigate the feasibility, methods and the primary results of utilizing music as a means of habilitation of children with cochlear implant. STUDY DESIGN: A habilitation program based on music training is developed. The results are presented as a case-series. METHODS: Music Training Program is introduced as a new habilitation program. Methods of training (based on Orff method) and measuring the outcomes are introduced in this paper. Effects of this program on other habilitation programs and overall hearing related skills of children were also investigated by open questioning of the parents and the habilitation staff. RESULTS: Twenty-three children, (age: 2.5-12.5 years) were selected. All children showed appreciable progress in playing a musical instrument. The effects on other habilitation processes were significant and all parents expressed their satisfaction with the program, as they perceived its benefits. DISCUSSION: The necessity of adding Music Training Program to the routine habilitation may be summarized as follows: Music is a feature of sound, which should be mastered. The psychological effects of being able to accomplish a hearing-related task can add to the self-esteem of children and help prevent and reduce anxiety. Music is a habilitation method: Introducing new concepts of sound, like temporal and frequency-related characteristics, is a crucial part of the habilitation of a child with cochlear implant. Practising new concepts needs motivation, too. We emphasize on using all means of rehabilitation and encourage teaching music to cochlear implant children between 4 and 5 years of age having approximately 4 months of experience with cochlear implant.

Adolescent↗

PubMed2001

Channel weights for speech recognition in cochlear implant users.

The purpose of this study was to develop and validate a method of estimating the relative "weight" that a multichannel cochlear implant user places on individual channels, indicating its contribution to overall speech recognition. The correlational method as applied to speech recognition was used both with normal-hearing listeners and with cochlear implant users fitted with six-channel speech processors. Speech was divided into frequency bands corresponding to the bands of the processor and a randomly chosen level of corresponding filtered noise was added to each channel on each trial. Channels in which the signal-to-noise ratio was more highly correlated with performance have higher weights, and conversely, channels in which the correlations were smaller have lower weights. Normal-hearing listeners showed approximately equal weights across frequency bands. In contrast, cochlear implant users showed unequal weighting across bands, and varied from individual to individual with some channels apparently not contributing significantly to speech recognition. To validate these channel weights, individual channels were removed and speech recognition in quiet was tested. A strong correlation was found between the relative weight of the channel removed and the decrease in speech recognition, thus providing support for use of the correlational method for cochlear implant users.

Adult↗

PubMed1996

[Cochlear implant in inner ear abnormalities and footplate malformation].

BACKGROUND: Malformations of the cochlea can cause deafness and otogenic meningitis. Cochlear implantation in children with such malformations, which are sometimes quite complex, require special attention before, during and after surgery. PATIENT: The concept developed for these patients at Hannover Medical School is illustrated in a patient with severe bilateral inner ear malformation and bilateral stapes defect. Implantation of a cochlear implant was performed in this 2-year-old girl. A large endostal sack originating from the inner ear, which had caused meningitis twice, was observed in the right middle ear. Both ears had to be obliterated to prevent recurrent meningitis. RESULTS: The child had no post-operative problems and the initial rehabilitation efforts have been successful. The immediate and differentiated reactions to stimulation are very encouraging. This article briefly summaries all diagnostic and therapeutic procedures established over the last three years at Hannover Medical School in cases of implantation into a malformated cochlea. In particular, we describe perioperative radiology (CT scans, MRI and plain radiographs), facial nerve monitoring and intraoperative screening for "hearing sensations", details of surgical technique, and possible postoperative complications. CONCLUSIONS: Based on experience with 13 of these cases, we discuss the different aspects of implantation into a malformated cochlea. Given certain preconditions implantation into a malformated cochlea may be recommended.

Child, Preschool↗

PubMedDate not supplied

The cochlear implant in preschool-aged children.

Long-term experience with the single-electrode cochlear implant has shown this device to provide significant benefit with minimal risk to the deaf adult. Based on these findings, the decision was made to begin implanting children. As of September 1, 1982, 27 profoundly deaf children (ranging in age from 2.7 to 17.5 years) have received the cochlear implant. Tests results are consistent with those found in adults, and the children have adapted well to using the device. Of particular interest are the results observed in the preschool-aged children, eight of whom have been implanted. Two of these children have now had the implant for a year. Findings to date indicate that progress with the implant is initially slower for the preschool-aged child than for older children and adults. In time, however, similar results are attained. Ultimately the younger children adapt even better to the device. These preliminary results are encouraging, but only long-term experience with a large number of subjects will better determine the benefits of the cochlear implant for the preschool-aged child.

Adult↗

PubMed1987

Meningitis and facial paresis. Implications for cochlear implantation.

Most postlingually deafened individuals receive auditory sensations with a cochlear implant. We describe a postmeningitic patient with bilateral facial paresis who failed to be stimulated with a multichannel device. In light of the facial dysfunction, primary auditory nerve damage by meningitis is postulated as the cause of implant failure. Preoperation electrical stimulation of the cochlea using an alternating current signal is recommended as a means of assessing cochlear implant candidacy.

Cochlear Implants↗