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PubMed2003

Exploring the language and literacy outcomes of pediatric cochlear implant users.

OBJECTIVE: The principal goal of this study was to investigate the relationship between language and literacy (i.e., reading and writing) skills in pediatric cochlear implant users. A peripheral objective was to identify the children's skills that were in need of remediation and subsequently to provide suggestions for remedial programming. It was predicted that the robust language skills often associated with children who have cochlear implant experience would facilitate the development of literacy skills. It was further proposed that the language and literacy skills of pediatric cochlear implant users would approximate the language and literacy skills of children with normal hearing. DESIGN: Sixteen pediatric cochlear implant users' language and literacy skills were evaluated and then compared with a reference group of 16 age-matched, normal-hearing children. All 32 participants were educated in mainstream classes within the public school system in the Midwest. The "Sentence Formulation" and "Concepts and Directions" subtests of the Clinical Evaluation of Language Fundamentals-3 test were used to evaluate receptive and expressive language skills. Reading comprehension was evaluated with the "Paragraph Comprehension" subtest of the Woodcock Reading Mastery Test. Performance measures for the writing analyses included productivity, complexity and grammaticality measures. RESULTS: Children with cochlear implants performed within 1 SD of the normal-hearing, age-matched children on measures of language comprehension, reading comprehension and writing accuracy. However, the children with cochlear implants performed significantly poorer than the children with normal hearing on the expressive "Sentence Formulation" subtest. The cochlear implant users also produced fewer words on the written narrative task than did the normal-hearing children, although there was not a significant difference between groups with respect to total words per clause. Furthermore there was a strong correlation between language performance and reading performance, as well as language performance and total words produced on the written performance measure for the children using cochlear implants. CONCLUSIONS: The results of this study suggest that the language skills of pediatric cochlear implant users are related to and correlated with the development of literacy skills within these children. Consequently, the performance of the cochlear implant users, on various language and literacy measures, compared favorably to an age-matched group of children with normal hearing. There were significant differences in the ability of the cochlear implant users to correctly utilize grammatical structures such as conjunctions and correct verb forms when they were required to formulate written and oral sentences. Given this information, it would be appropriate for their educational or remedial language programs to emphasize the use and development of these structures.

Child↗

PubMed2000

Mismatch negativity: a tool for the assessment of stimuli discrimination in cochlear implant subjects.

OBJECTIVES: The performance of cochlear implants varies among users. This variability may be due to the ability to process auditory information. The mismatch negativity should provide an index of discrimination in cochlear implantees (Kraus N, McGee T, Carrell T, Sharma A. Neurophysiologic bases of speech discrimination. Ear Hear. 1995;16:19-37). Our aim was to analyze MMN in cochlear implant (Digisonic) subjects to assess electrode discrimination and to study the relationship between MMN and speech performance. METHODS: The mismatch was determined by stimulating three pairs of different electrodes. Two sessions were performed with both standard and deviant stimuli reversed. Speech recognition abilities were evaluated using 4 speech tests. The statistics included the results of 6 subjects. They indicated that MMN may be obtained when stimulating two different electrodes. A difference occurred between standard and deviant stimuli within a session but also when the response to the deviant stimulus was compared to the response of the same stimulus in a standard condition, validating the discrimination process. MMN latency was about 140 ms, and amplitude about -2.8 microV. No differences were shown with respect to electrode spacing. No relationship between MMN and speech performance was found. A clinical application of this method might be to assess the auditory processing of electrical stimuli in congenitally deaf subjects at the pre-implantation stage.

Acoustic Stimulation↗

PubMed1998

Speech perception in children after cochlear implantation.

OBJECTIVE: This study aimed to determine the speech perception ability of congenitally and prelingually deaf children after cochlear implantation. STUDY DESIGN: A prospective study was undertaken on a consecutive group of 119 congenitally and prelingually deaf children up to 5 years after implantation. The study group was confined to children between 2 and 7 years of age at the time of implantation. All were implanted with multichannel cochlear implant systems. No child was lost to follow-up, and there were no exclusions from the study other than one child with auditory nerve aplasia. METHODS: The Iowa Matrix Closed Set Sentence Test and Connected Discourse Tracking were used to assess closed- and open-set speech perception, respectively, without lip reading. SETTING: The study was conducted at a tertiary referral pediatric cochlear implant center in the United Kingdom. RESULTS: It was possible to formally test closed-set speech discrimination on 83, 55, 32, 21, and 15 children at 12, 24, 36, 48, and 60 months, respectively. On the Iowa Matrix Test, the median score was 0% at 12 months, reaching a plateau of 99% at 36 months. On Connected Discourse Tracking, the median scores at 12, 24, 36, 48, and 60 months were 0, 0, 21, 40, and 53 words per minute, respectively. CONCLUSION: Congenitally and prelingually deaf children who receive cochlear implants before the age of 7 years have significant closed-set speech perception abilities develop in <3 years after implantation. Their ability to perform open-set tasks without lip reading is limited in the first 2 years but shows significant improvement, not reaching a plateau, at the 4-5-year interval after implantation.

Age Factors↗

PubMed1996

Otitis media in children with cochlear implants.

Fifty children who received a cochlear implant between 1991 and 1995 were evaluated for incidence of acute otitis media (AOM). Thirty-seven (74%) children had AOM before implantation and 8 (16%) after implantation. All children who had AOM after implantation had a history of AOM. A subgroup of 14 children required ventilating tubes for recurrent AOM before implantation. Five (35.7%) in this group had AOM after implantation. The incidence and severity of AOM decreased after implantation. All episodes of postimplant AOM were successfully treated with routine oral antibiotics, and no infectious complications occurred. A history of recurrent AOM should not inordinately delay cochlear implantation.

Acute Disease↗

PubMed1997

Speech perception performance of congenitally deaf patients with a cochlear implant: the effect of age at implantation.

The relation between age at cochlear implantation and long-term open-set speech recognition was studied in a group of nine congenitally deaf children. The age at cochlear implant surgery ranged from 4 to 13 years. The results showed that there was a tendency toward poorer results in the children implanted at a relatively older age. However, the results also indicated that an upper limit for age at implantation cannot yet be defined in these children.

Adolescent↗

PubMed1995

Cochlear implantation in the congenital malformed cochlea.

Cochlear implantation has proven beneficial for numerous children with profound congenital hearing impairments. Some congenitally deaf ears, however, may have anatomical malformations. This study reports the authors' recent experience with cochlear implants in patients with cogenital inner ear malformations. Since 1987, 10 patients with congenital abnormal inner ear structures have been implanted at the House Ear Clinic; 8 with abnormal cochleas and 2 with enlarged vestibular aqueducts. Nine patients received the Nucleus 22 device and 1 patient was implanted with the 3M/House device. Some modifications of the routine surgical approach were required in 5 patients. A cerebrospinal fluid (CSF) leak occurred in 4 of the 10 cases. There was a relationship between the degree of abnormality and the number of electrodes that could be inserted. All 10 patients can perceive sound and are active users of their implants.

Aged↗

PubMed1999

Cochlear implants: response to therapeutic irradiation.

PURPOSE: To determine the response of cochlear implants ("bionic ears") to therapeutic irradiation. METHODS AND MATERIALS: A patient with a cochlear implant was referred for palliative cranial irradiation. As there were no published or manufacturer's data available regarding the response to radiation, implants were tested for functional changes following irradiation. Cochlear implants were supplied by Cochlear Ltd. Two units each of models CI22M, CI22M (with the second generation integrated circuit) and CI24M were irradiated with 4 MV X-rays, and an unirradiated unit of each model was used as a control. The implants were irradiated initially with 25 daily fractions to 50 Gy. To determine the response at higher doses, 10 Gy fractions were delivered to the same implants to 100 Gy, followed by a final fraction of 50 Gy (total dose 150 Gy). The implants were tested after each 10 Gy, up to 1100 Gy, and at 150 Gy. Several indicators of functionality were assessed, including RF (radio frequency) link range, and stimulator output current. The radiation shielding effect of the implants was also assessed. RESULTS: Within the dose range < or = 50 Gy, the stimulator output current of the CI22M units was the only parameter to change. At higher doses (to 150 Gy), changes in current output continued, and gradual loss of RF link range occurred in the CI22M units. The CI24M units showed changes in output current to 100 Gy, and large changes at 150 Gy. Dose attenuation by the implants was measured at 6% for ipsilateral single field 4 MV X-rays. CONCLUSION: Our results suggest that patients with these cochlear implants can receive cranial irradiation with a low risk of implant failure. Changes in stimulator output current can be compensated simply by reprogramming the speech map after the course of radiation treatment.

Adenocarcinoma↗

PubMed1999

A 4-year investigation into phonetic inventory development in young cochlear implant users.

Phonetic inventories of 9 children with profoundly impaired hearing who used the 22-electrode cochlear implant (Cochlear Limited) were monitored before implantation and during the first 4 years of implant use. All children were 5 years old or younger at the time of implant. Spontaneous speech samples were collected at regular intervals for each child and analyzed to investigate phone acquisition over the post-implant period. Acquisition was measured using two different criteria. The "targetless" criterion required the child to produce a phonetically recognizable sound spontaneously, and the "target" criterion required the child to produce the phone correctly at least 50% of the time in meaningful words. At 4 years post-implant, 40 out of 44 phones (91 %) had reached the targetless criterion, and 29 phones (66%) had reached the target criterion for 5 or more of the children. Over the time of the study 100% of monophthongs, 63% of diphthongs, and 54% of consonants reached the target criterion. The average time taken for a phone to progress from the targetless to target criterion was 15 months. Overall, the data suggest trends in the order of phone acquisition similar to those of normally hearing children, although the process of acquisition occurred at a slower rate.

Child, Preschool↗

PubMed1994

[Criteria and procedures for selection of children with acquired or congenital deafness for cochlear implants in Europe].

The Nucleus Mini System 22 cochlear implant has been implanted in over 2,000 children worldwide. Selection criteria have evolved similar to that for adults since implantation in children began in 1985. The appropriate selection of children for implantation is made by a professional pediatric team which considers audiological and non-audiological issues in determining if the child is a cochlear implant candidate. The main philosophy is to establish if the child has the potential to benefit from a cochlear implant.

Adaptation, Psychological↗

PubMed1998

Vestibular stimulation by multichannel cochlear implants.

The recipient of a Nucleus 22 multichannel cochlear implant began to experience severe vestibular stimulation related to the implant. This patient's experience initiated a study with the objective of determining the frequency of implant-related vestibulo-ocular stimulation. Subjects consisted of 17 randomly selected patients who use cochlear implants. Included in the study were 14 Nucleus 22 and three Med-El Combi 40-devices. Stimulation of the implants was performed both by individual channel and with sound field broad-band 80-dB noise using the users' normal device settings. Eye movements were monitored with infrared videonystagmography. Only one subject, who used a Med-El Combi 40, showed a consistent and strong ocular response to cochlear stimulation but had no subjective symptoms. The authors conclude that vestibulo-ocular activation is possible with multichannel cochlear implants but is infrequent and may not be clinically significant.

Cochlear Implants↗

PubMed2005

Pattern of hearing loss in a rat model of cochlear implantation trauma.

HYPOTHESIS: Trauma caused by cochlear implant electrode insertion is attributable to the combination of direct physical trauma and the delayed cell death of oxidative stress-injured auditory sensory cells. BACKGROUND: Histologic evaluation of cochlear implant electrode trauma has demonstrated that the extent of sensory cell losses is proportional to the degree of injury. However, the impact of delayed oxidative stress within injured cochlear tissues and the progressive loss of injured hair cells by way of apoptosis are at present unknown. METHODS: Laboratory rats were evaluated for hearing acuity before and after electrode insertion, before and after round window membrane incision only. Hearing was measured before trauma or incision and over the next 7 days. Objective measurements of hearing function were distortion products of otoacoustic emissions (DPOAEs) in the frequency range of 2 to 32 kHz and tone-burst (i.e., 4-32 kHz) evoked auditory brain stem responses (ABRs). RESULTS: For the experimental cochleae, there were progressive increases in ABR thresholds and decreases in ABR amplitudes. The amplitude of the DPOAEs in the experimental cochleae also showed progressive decreases. For the contralateral control and round window membrane surgical control ears, there were no significant changes in either DPOAE or ABR thresholds. CONCLUSION: These results document a progressive loss of hearing acuity postimplantation and strongly suggest that electrode insertion trauma generated oxidative stress within injured cochlear tissues.

Animals↗

PubMed2006

The effect of Gaussian noise on the threshold, dynamic range, and loudness of analogue cochlear implant stimuli.

The deliberate addition of Gaussian noise to cochlear implant signals has previously been proposed to enhance the time coding of signals by the cochlear nerve. Potentially, the addition of an inaudible level of noise could also have secondary benefits: it could lower the threshold to the information-bearing signal, and by desynchronization of nerve discharges, it could increase the level at which the information-bearing signal becomes uncomfortable. Both these effects would lead to an increased dynamic range, which might be expected to enhance speech comprehension and make the choice of cochlear implant compression parameters less critical (as with a wider dynamic range, small changes in the parameters would have less effect on loudness). The hypothesized secondary effects were investigated with eight users of the Clarion cochlear implant; the stimulation was analogue and monopolar. For presentations in noise, noise at 95% of the threshold level was applied simultaneously and independently to all the electrodes. The noise was found in two-alternative forced-choice (2AFC) experiments to decrease the threshold to sinusoidal stimuli (100 Hz, 1 kHz, 5 kHz) by about 2.0 dB and increase the dynamic range by 0.7 dB. Furthermore, in 2AFC loudness balance experiments, noise was found to decrease the loudness of moderate to intense stimuli. This suggests that loudness is partially coded by the degree of phase-locking of cochlear nerve fibers. The overall gain in dynamic range was modest, and more complex noise strategies, for example, using inhibition between the noise sources, may be required to get a clinically useful benefit.

Adult↗

PubMedDate not supplied

Electrically evoked auditory middle latency responses versus perception abilities in cochlear implant users.

Electrical auditory middle latency responses (EAMLRs) were recorded in a group of 12 postlingually and 4 congenitally deaf cochlear implant users. The EAMLRs of the postlingually deaf cochlear implant users were compared to behavioral measures of speech perception. All the cochlear implant users showed pronounced EAMLR morphology and amplitude. EAMLRs of congenitally deaf cochlear implant users were remarkably similar to those of postlingually deaf cochlear implant users. The difference in speech perception ability between congenitally deaf and postlingually deaf cochlear implant users did not seem to be caused by integrity differences of the neural generators of the auditory middle latency response. For the postlingually deaf subjects, EAMLR amplitude variation and interlatency variation seemed to be related to specific aspects of speech perception. The poorer performers demonstrated more diversity in the amplitude of the EAMLR component peaks and a more diffuse EAMLR peak latency organization across the electrodes than the better performers.

Adolescent↗

PubMed1995

Speech-evoked cognitive P300 potentials in cochlear implant recipients.

The cognitive P300 evoked potential was elicited by speech stimuli in successful cochlear implant recipients, and the resulting P300 morphology was remarkably similar to that of normal-hearing individuals. The P300 was elicited by the synthesized speech pair/da/and/di/ presented using an oddball paradigm to nine "good" Nucleus cochlear implant users and nine age-matched normal-hearing subjects (34-81 yr old). There were no significant differences in P300 amplitude and latency between the two groups. Moreover, the N1 and P2 potentials occurred at similar latencies in the two groups, although the N1 amplitude was significantly smaller in the cochlear implant users. The P300 was absent in one "poor" cochlear implant user. The results suggest that the P300 may serve as a useful tool for evaluating the cognitive aspects of auditory processing in cochlear implant recipients, and that it may aid in assessing the success of cochlear implantation.

Acoustic Stimulation↗

PubMed2004

Bacterial biofilms may contribute to persistent cochlear implant infection.

OBJECTIVES: To determine if bacterial biofilms are present on the surface of extruding or persistently infected cochlear implants. METHODS: Scanning electron microscopy was performed on cochlear implants removed from two patients because of recalcitrant infection, two implants removed secondary to device failure, and two devices that had never been implanted. Preparations were examined by experienced microbiologists for the presence of bacterial biofilms. RESULTS: Microorganisms and amorphous extracellular debris were found on the surface of the infected cochlear implants and the implants removed because of device failure. Biofilm formation was deemed definite in one infected device and possible in the other explanted devices. The never-implanted controls demonstrated microbial contamination without exopolymeric matrix, inconsistent with biofilms. CONCLUSION: Bacterial biofilm formation may play a role in recalcitrant cochlear implant infections. This may have profound implications for the treatment of cochlear implant infections.

Adolescent↗

PubMed1988

The role of cochlear implants in deaf children.

Advances in technology regarding cochlear implantation and electroacoustic stimulation of the inner ears of deaf children has created cautious enthusiasm. The safety of cochlear implantation is now reasonably well established and language performance measures made over time are encouraging. When coupled with an effective (re)habilitation program, the cochlear implant promises to favorably influence the potential of deafened children.

Adolescent↗

PubMed2004

[Multi-channel cochlear implants in patients with Mondini malformation].

OBJECTIVE: To describe clinical experiences with multi-channel cochlear implantation in patients with Mondini malformation. METHODS: Among 300 patients who received multi-channel cochlear implants from 1996 to 2002 in Beijing Tongren Hospital, 15 patients were diagnosed with Mondini malformation. A retrospective analysis was performed dealing with the surgical techniques, mapping and rehabilitations characteristics after surgery. 15 patients with normal cochlear structure are consider as control group. RESULTS: Gusher is found more common than the normal cochlear implantation, most of them are serious. The electrodes are inserted in the "cochleostomy" in full length of 13 Patients, 2 pairs of electrodes remains outside of "cochleostomy" in 2 patients. No serious complications occurred after implantation. All patients have auditory sensations. The impedance of the electrodes, the T level, C level and the hearing threshold are similar with the normal cochlear implantation group. The results have no significant difference in compare with normal cochlear group(P > 0.05). CONCLUSION: Multi-channel cochlear implantation could be performed safely in patients with Mondini malformation. The primary outcome for patients with Mondini malformation are similar to those with normal cochlear structure following the multi-channel cochlear implantation.

Adolescent↗

PubMed2004

MRI versus CT in assessment of cochlear patency in cochlear implant candidates.

OBJECTIVE: To investigate how cochlear patency as seen on preoperative CT and MRI scans correlates with findings at surgery in cochlear implant patients. MATERIAL AND METHODS: CT and MRI scans of 25 patients were reviewed by 3 independent observers. The reviewers classified the cochlear patency and recorded the location of any suspected decrease in patency. Their results were compared with the findings noted during surgery. RESULTS: Decreased cochlear patency was found in six patients at surgery. The mean sensitivity/specificity of CT and MRI assessment was 33%/88% and 41%/91%, respectively. CONCLUSION: Our study suggests that CT, using axial and semi-longitudinal planes, is equivalent to MRI in predicting cochlear patency.

Cochlea↗