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PubMed1999

[Suprasegmental speech in prelingual hearing-impaired children with cochlear implants, hearing-impaired children without implants and normal hearing children].

A review of the relevant literature indicates a lack of knowledge regarding suprasegmental speech characteristics in prelingual hearing impaired children with cochlear implants. This study is aimed at examining certain suprasegmental features in the speech of prelingual hearing impaired children with cochlear implants by perceptual ratings and acoustic analyses, comparing these results to that of prelingual hearing impaired children without implants, and normal hearing children of the same age. Twelve Afrikaansspeaking children between the ages of six and ten years were included in three groups. An integrated view of the perceptual and acoustic results shows that the cochlear implanted children's suprasegmental speech characteristics bear closer resemblance to those of the normal hearing group than those of the hearing impaired group.

Child↗
PubMed2006

Favorable outcome of cochlear implant in VIIIth nerve deficiency.

OBJECTIVE: To report on the outcomes of cochlear implantation (CI) in a child with cochleovestibular nerves (CVN) hypoplasia. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center, University hospital. PATIENTS: An 18-month-old child with profound bilateral congenital hearing loss and bilateral hypoplasia of the CVN at imaging. INTERVENTION: Left CI at age 29 months with a Nucleus Contour device (Cochlear Ltd., Lane Cove, New South Wales, Australia) after unsatisfactory results of hearing aid use for 10 months. MAIN OUTCOME MEASURES: Speech perception tests, behavioral observation, electrophysiologic tests, and cognitive evaluation. RESULTS: Although the child scores poorly in every perceptive category with the CI alone, the device greatly enhances his speech understanding with the hearing aid in the opposite ear. In the bimodal condition, his words and sentences identification, recognition, and comprehension far exceed the monaural figures. The Meaningful Auditory Integration Scale (MAIS) tests reaches a score of 26/40, and the MacArthur's questionnaires confirm the improvement of language production and comprehension. These results became noticeable after 5 to 6 months and continued to improve up to the 10th month. The child's cognitive scores and overall performance competences greatly benefit from the CI, with the mental age overcoming the chronological age. CONCLUSION: We can confirm the chance of achieving satisfactory results by CI even when the imaging of CVN is doubtful and the electrophysiological tests are disappointing. In our experience, a CI in Type IIb dysplasia of the CVN is a feasible option, provided that the candidate shows some responses at aided audiogram and at least minimal signs of language development. Adequate counseling is necessary for these children because the expected outcome is somewhat lower than that of their deaf peers with normal appearance of the nerves.

Audiometry, Pure-Tone↗
PubMed2003

[A comparison between findings of high resolution computed tomography and magnetic resonance imaging in the preoperative assessment of cochlear implant patients].

OBJECTIVES: We compared the preoperative findings of high resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) with those observed during surgery to determine their value for cochlear implant patients. PATIENTS AND METHODS: A retrospective assessment was made on preoperative HRCT and MRI scans of 124 cochlear implant patients (71 males, 53 females; mean age 15 years; range 2 to 63 years). Congenital cochlear anomalies, cochlear ossification, new bone formation in the middle ear, and structures in the internal auditory canal were evaluated and compared with intraoperative findings. RESULTS: Cochlear anomalies detected in five patients by HRCT and MRI were confirmed intraoperatively. Cochlear ossification encountered in six patients during surgery was only demonstrated in four patients; HRCT and MRI scans only showed a narrow basal turn in the remaining two patients. During surgery, eight patients were found to have cochlear fibrosis: this finding was documented in five patients (62.5%) by MRI, and in none by HRCT scans. CONCLUSION: Although HRCT provides valuable information for surgical planning, its limitations may justify the additional use of MRI before cochlear implantation.

Adolescent↗
PubMed2004

Cochlear implantation in a Mandarin Chinese-speaking child with auditory neuropathy.

Auditory neuropathy (AN) is a hearing disorder characterized by the preservation of outer hair cell function despite the absence of auditory brainstem responses. The pathophysiology and etiology of this condition remain unknown. Recent studies have shown that some patients with AN benefit significantly from cochlear implantation. These patients have all been native speakers of Western languages. A 3-year-old Mandarin-speaking boy was referred to our center because of speech delay. After a series of audiological surveys, retro-cochlear lesion was impressed. During the 2-year period of rehabilitation, poor speech discrimination out of proportion to aided hearing thresholds led to the diagnosis of auditory neuropathy. Because of the limited benefit from amplification, he received a cochlear implant. Significant improvement of speech perception skills assessed by a Mandarin auditory perception test was noted shortly after implantation. The post-implantation performance in this Mandarin-speaking child was consistent with that of reports for implantees speaking Western languages. For Mandarin-speaking children with AN who fail to benefit from conventional treatment, cochlear implantation may be a good alternative choice.

Child, Preschool↗
PubMed2003

Channel interactions with high-rate biphasic electrical stimulation in cochlear implant subjects.

Channel interactions were assessed using high-rate stimulation in cochlear implant subjects using the Ineraid electrode array. Stimulation currents were applied on one intracochlear electrode and their effects on psychophysical detection thresholds on an adjacent electrode were measured. Stimuli were trains of brief, biphasic, 50-micros/phase pulses presented at a rate of 2000 pulses per second per channel. In experiment I, we studied how the detection of a probe signal was influenced by a sub-threshold perturbation signal presented either simultaneously or non-simultaneously (with no overlap) on an adjacent electrode. Results showed that simultaneous activation led to strong channel interactions, producing threshold changes consistent with instantaneous electric field summation. Non-simultaneous activation revealed much weaker interactions, producing threshold changes of opposite sign. In experiment II, we studied how the temporal delay between perturbation and probe pulses, as well as how the level of the perturbation signal influenced non-simultaneous channel interactions. First, threshold changes when reversing the polarity of the perturbation did progressively vanish when increasing the delay between pulses. This suggested that non-overlapping stimulation of adjacent electrodes produced channel interactions that were in part due to residual polarization of the nerve membrane. Second, increasing the perturbation to supra-threshold levels produced threshold elevations that were independent of the interpulse interval. This suggested channel interactions due to neural masking. These results provide insights into the different concurrently active mechanisms of channel interactions in cochlear implant systems using this type of stimuli.

Adult↗
PubMed1999

Effects of discrimination difficulty on cognitive event-related brain potentials in patients with cochlear implants.

Cognitive event-related brain potentials (ERPs) recorded during a 2-tone discrimination (oddball) task were examined in 8 patients with cochlear implants. The aim of this study is to investigate the effects of discrimination difficulty formed by 4 conditions of stimulus contrast: the target stimuli were set at 2000, 1500, 1200, or 1100 Hz, and nontarget stimuli were set at 1000 Hz throughout. The averaged ERPs recorded after the target stimuli revealed N100, P200, N200, and P300 peaks, whereas those after the nontarget stimuli showed only N100 and P200 peaks. The peak latencies of the ERP components of early information processings (N100 and P200) were not significantly increased among the 4 conditions. In contrast, the latencies of late cognitive components (N2b and P300, whose peak latencies were longer than 250 msec) and reaction times were significantly increased as target discriminability decreased. In conclusion, early information processings were not delayed by the discrimination difficulty, but cognitive processings were delayed in patients with cochlear implants. Because the N2b amplitude, which is considered to be associated with controlled processings, was much larger than that previously reported from subjects with normal hearing, it is suggested that patients with cochlear implants make a considerable effort to process their poor auditory information.

Adult↗
PubMed2002

[Radiological study of temporal bone in children with profound deafness before cochlear implant: CT vs magnetic resonance imaging].

OBJECTIVE: To evaluate the clinical application of magnetic resonance imaging (MRI) and CT in children with profound deafness before cochlear implant and their impact on surgical decision. METHODS: The pre-operative CT and MRI data from 71 children with bilateral profound deafness planned for cochlear implant were studied. RESULTS: 12 patients showed enlarged vestibular aqueduct (16.9%); 14 patients had Mondini malformation (19.7%); 3 patients demonstrated enlarged internal auditory meatus (4.2%); and 2 patients were suspected to have fistulae (2.8%) on both CT and MRI examinations. In comparison between MRI and CT, unilateral cochlear fibrosis was detected in 5 patients(7%) by MRI, but none by CT scans. Bilateral dehiscent facial nerve was detected in 1 patient(1.4%) by CT scan, while MRI was normal. CONCLUSION: CT and MRI are essential for the pre-operative planning of cochlear implant, especially in patients with enlarged vestibular aqueduct, Mondini malformation, enlarged internal auditory meatus and suspected fistulae. These two imaging modalities are complementary to each other in cases with cochlear fibrosis and facial nerve dehiscence.

Child↗
PubMed1999

Hearing results with deep insertion of cochlear implant electrodes.

OBJECTIVE: This study aimed to investigate the relationship of electrode insertion length and speech recognition in patients using Nucleus-22 cochlear implants. STUDY DESIGN: The study design was a retrospective review of a consecutive clinical series. SETTING: The study was conducted at an academic medical center. PATIENTS: Thirty-one postlingually deafened adults with at least 6 months' experience with a Nucleus-22 cochlear implant using Spectra-22 processor and SPEAK strategy participated. MAIN OUTCOME MEASURES: Open-set speech recognition scores for words and sentences were measured. RESULTS: Insertion length ranged from 22 rings (estimated 17 mm) to 32 rings (estimated 25 mm). Mean word recognition score was 35%. Mean sentence score was 69.6%. Statistical analysis showed no correlation between insertion depth and word or sentence scores. CONCLUSION: Insertion of the Nucleus-22 array beyond 22 rings does not improve performance in speech recognition. This finding cannot be generalized to other electrodes or processing strategies.

Adult↗
PubMed1987

Indications for multi- or single-channel cochlear implant for rehabilitation of total deafness.

Only totally deaf patients who do not experience improvement when using classical hearing aids are candidates for a cochlear implant. Preoperative assessment of potential benefits of a cochlear implant may improve selection of patients with pre- or postlingual total deafness, so that the most appropriate system can be implanted. The psychological status of potential candidates for implantation is particularly important because the results of postoperative re-education depends on motivation of the patient. The Round Window electrical stimulation test supplies us with important and measurable data (electrical threshold level, tone decay test). The duration of deafness, the degree of the deafness, and the cochlear tomodensitometry do not affect the decision to implant a cochlear device, (i.e., since the socialization level of the patient is a considerable factor). Preoperative assessment of the patient is very useful. As a result of our experience in 115 implanted cases suffering from pre- and postlingual deafness, we are now able to predict the good or bad results in our patients. Therefore, in patients who have many adverse factors for recovery, it seems to us more reasonable and cheaper to implant a single-channel system instead of a multichannel system, which must be reserved for patients who should do well. In very young children, the most appropriate system seems to be extra cochlear single-channel implant.

Cochlear Implants↗
PubMed2003

[Bilateral total deafness due to mumps and the outcome of cochlear implantation].

OBJECTIVE: Bilateral deafness due to mumps is rare. Here report three cases of bilateral total deafness due to mumps and their outcome of cochlear implantation. METHOD: Three cases of bilateral total deafness due to mumps were reviewed. RESULT: All patients had sudden bilateral total deafness in 3 to 7 days after mumps. 2 had vestibular symptoms. Cochlear implantation has been successful in all 3 patients. Three month after the initial mapping, Case 2 who has been wearing bilateral hearing aids and received one-year language training has the best outcome of hearing and speech than the other two. Case 1 who has been wearing one-side hearing aid and received language training of 6 months has the better outcome than case 3 who has never worn hearing aid and never received language training. CONCLUSION: Hearing loss caused by Mumps is often sudden in onset, conservative therapy have no help. Hearing aid and language training are very important to the outcome of speech perception and speech production after cochlear implantation.

Adolescent↗
PubMed2002

Cochlear implants in systemic autoimmune vasculitis syndromes.

The concept that autoimmunity may damage the inner ear was introduced by McCabe in 1979. Audiovestibular symptoms may occur in isolation or may be mediated by vasculitis in patients affected by systemic autoimmune disorders. Sensorineural hearing loss (SNHL) is typical in Cogan's syndrome but occurs less frequently in Beçhet's syndrome and in systemic necrotizing vasculitides. Patients affected by immune-mediated profound SNHL represent ideal candidates for cochlear implantation as these patients become deaf after years of hearing. The disease itself and the medication taken may, however, influence the prognosis of cochlear implantation in these patients. We retrospectively evaluated the pre- and intraoperative findings as well as the postoperative course and performance of a group of five patients affected by a systemic vasculitis syndrome who received a cochlear implant. Implantation was successful in all patients, no complications occurred and excellent postoperative speech perception was achieved. We conclude that cochlear implantation in patients affected by immune-mediated inner ear disorders is effective although the long-term results remain to be evaluated.

Adult↗
PubMed2001

Is there a functioning vestibulocochlear nerve? Cochlear implantation in a child with symmetrical auditory findings but asymmetric imaging.

The finding of an abnormally narrow internal auditory meatus during the assessment of a child for cochlear implantation raises the possibility that the meatus may not contain the normal number of nerves. Even with currently available MRI techniques it may be extremely difficult to decide whether or not to offer cochlear implant in such cases. We present a child of 4 1/2 years, assessed for cochlear implantation. MRI and CT imaging suggested aplasia of one vestibulocochlear nerve and hypoplasia of the other. However, audiological tests showed clear responses to sound in both ears and functional use of sound in her daily life. This child was eventually implanted with encouraging postoperative results.

Audiometry↗
PubMed1995

Analytic importance of the coding features for the discrimination of vowels in the cochlear implant signal.

The present study considers the analytic importance of the excitation pulse features delivered by a Nucleus cochlear implant using the F0F1F2 strategy. Four cochlear implant patients and 10 speakers uttering two 48-item lists constructed from four basic French vowels participated in this study. Patterns were presented to the patients and played at the input of an acquisition system in order to record the pulse features. Confusion matrices obtained with the patients and with automatic recognition procedures were then compared in order to find out the best-matching models simulating the patients' performances, out of 255 possibilities. The automatic recognition was carried out according to fuzzy logic based on the elementary features of the pulses coding the vowels. Results show that the essential features strongly depended on the subject.

Adult↗
PubMed1992

Effects of short-term auditory deprivation on speech production in adult cochlear implant users.

Speech production parameters of three postlingually deafened adults who use cochlear implants were measured: after 24 h of auditory deprivation (which was achieved by turning the subject's speech processor off); after turning the speech processor back on; and after turning the speech processor off again. The measured parameters included vowel acoustics [F1, F2, F0, sound-pressure level (SPL), duration and H1-H2, the amplitude difference between the first two spectral harmonics, a correlate of breathiness] while reading word lists, and average airflow during the reading of passages. Changes in speech processor state (on-to-off or vice versa) were accompanied by numerous changes in speech production parameters. Many changes were in the direction of normalcy, and most were consistent with long-term speech production changes in the same subjects following activation of the processors of their cochlear implants [Perkell et al., J. Acoust. Soc. Am. 91, 2961-2978 (1992)]. Changes in mean airflow were always accompanied by H1-H2 (breathiness) changes in the same direction, probably due to underlying changes in laryngeal posture. Some parameters (different combinations of SPL, F0, H1-H2 and formants for different subjects) showed very rapid changes when turning the speech processor on or off. Parameter changes were faster and more pronounced, however, when the speech processor was turned on than when it was turned off. The picture that emerges from the present study is consistent with a dual role for auditory feedback in speech production: long-term calibration of articulatory parameters as well as feedback mechanisms with relatively short time constants.

Adult↗
PubMed2001

[Cochlear implants].

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Cochlear Implantation↗
PubMed2001

Does choosing the "worse" ear for cochlear implantation affect outcome?

OBJECTIVE: To determine whether choosing the "better" ear or the "worse" ear for cochlear implantation impacts performance outcome. DESIGN: Retrospective cohort study. SETTING: University teaching hospital-cochlear implant program. METHODS: Two groups of cochlear implantees were selected and matched based on clinical parameters, including duration of deafness/age at implantation, implant types, and processing strategies. Nineteen patients received an implant in his or her "better" ear of the two that had been amplified. An equal number of patients received an implant in the "worse" ear--an ear that was not amplified or was chosen to avoid causing oscillopsia; or if the patient was not willing to relinquish his or her hearing aid in the "better" ear based on subjective or objective criteria. Standard speech perception testing was performed. RESULTS: The average open-set speech perception responses at 1 year after implantation were as follows: word recognition score 40.4% and sentence recognition score 81% in the aided subjects (better ears); word recognition score 41.5% and sentence recognition score 84.5% in the unaided group (worse ears). CONCLUSION: No differences were found between the two groups of implantees. Choosing the "worse" ear for implantation did not appear to have a negative impact on performance outcome in this match-paired study.

Adolescent↗