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PubMed1998

Magnetic resonance imaging compatibility testing of the Clarion 1.2 cochlear implant.

OBJECTIVE: This study aimed to investigate the compatibility of the Clarion 1.2 magnet-containing cochlear implant with a 1.5-tesla (T) and 0.3-T magnetic resonance imager. BACKGROUND: Cochlear implants restore functional hearing to patients with sensorineural deafness. With the rapidly increasing number of patients with cochlear implants, there is a need to investigate the implant's magnetic resonance imaging (MRI) compatibility. METHODS: The authors tested the potential torque and force on the metallic components of the implant, heating of the implant and surrounding tissue, unintentional output, implant damage, and image distortion. Tests were performed in both a 1.5-T and 0.3-T MRI. RESULTS: The torque experienced by the implant in the 1.5-T MRI (0.19 nm) was large enough that it could potentially cause implant movement in some patients. An acceptable amount of torque (0.04 nm) was found in the 0.3-T MRI. Image distortion occurred in the area directly around the implant with a radius of up to 60 mm in the 1.5-T MRI and 100 mm in the 0.3-T MRI. In both MRI units, there was no detectable temperature increase or unintentional output. There was no implant damage except that with worst-case conditions, the internal magnet was demagnetized by 78.5% with the 1.5-T unit and 3.36% with the 0.3-T unit. CONCLUSIONS: The authors recommend patients with cochlear implants avoid imaging in a 1.5-T MRI. The results suggest that the 0.3-T MRI poses little or no risks to patients with cochlear implants.

Cochlear Implantation↗

PubMed1994

Long-term results of early cochlear implantation in congenitally and prelingually deafened children.

Cochlear implants have been shown to improve the speech perception and production skills in children. Data are available on congenitally and prelingually deafened children who were implanted at an older age, but data on children implanted below the age of 3 years are scarce. The present study examines the benefits obtained with early implantation of the young deaf child. Fourteen congenitally or prelingually profoundly hearing-impaired children were implanted before the age of 3 years, with the Nucleus multichannel cochlear prosthesis, and followed for 2-5 years. Results indicate an overall improvement in the perception of all aspects of the speech signal in the auditory-only condition with the cochlear implant. All the children use oral language as their primary mode of communication and attend regular schools. Based on the results of this investigation, the authors conclude that implantation of the young deaf child is beneficial to the development of auditory perceptual skills.

Age of Onset↗

PubMed2001

[Speech discrimination with bilateral cochlear implants in noisy conditions].

OBJECTIVE: To investigate the speech discrimination abilities of patients with bilateral cochlear implants. METHODS: The speech discrimination scores of Cantonese lexical tones were compared between two patients with unilateral and bilateral cochlear implants at different signal to noise (S/N) ratios. RESULTS: At favorable listening conditions with S/N ratios of +15, +10, and the mean binaural speech discrimination scores were 96%, 92% and 88%, but the mean monaural speech discrimination scores from the left and right ear were 86%, 83% and 74% respectively. At unfavorable listening conditions with adverse S/N ratios of 0, -5, -10 and -15, almost no speech discrimination scores could be obtained from monaural hearing but 80%, 72%, 68% and 54% respectively from binaural stimulation. CONCLUSION: Bilateral cochlear implants improve the discrimination of Cantonese lexical tones better than unilateral cochlear implant at various S/N ratios This study confirms the benefits of binaural hearing even in patients using bilateral cochlear implants.

Adult↗

PubMed1997

Tinnitus suppression in cochlear implant patients.

Tinnitus is sometimes suppressed by cochlear implantation. Tinnitus conditions were examined in 60 adult patients who underwent cochlear implantation in 1990 or later. Before surgery, 90% of these patients reported some type of tinnitus. The patients completed a questionnaire evaluating the loudness and duration of the tinnitus, immediately after the first electrical stimulation and 2 months later. The loudness of tinnitus was suppressed in 65% of the patients at first evaluation. Two months later, the tinnitus was suppressed in 93% of the patients. As for the duration of tinnitus, at first evaluation the tinnitus duration was suppressed in 41% of the patients. Two months later, the duration of tinnitus was suppressed in 61% of the patients.

Adult↗

PubMed2003

Developmental, audiological, and speech perception functioning in children after cochlear implant surgery.

OBJECTIVES: To examine changes in audiological, speech perception, and developmental functioning subsequent to cochlear implantation in children with severe to profound hearing impairment, and to identify factors related to those changes. DESIGN: Prospective, longitudinal analysis to compare functioning of pediatric patients who underwent cochlear implantation before and 1 year after surgery. SETTING: Outpatient pediatric cochlear implantation program in an academic institution (The Listening Center, The Johns Hopkins University School of Medicine, Baltimore, Md). Patients Forty consecutive pediatric patients between 1(1/2) and 9 years of age who received a cochlear implant between April 1, 1996, and August 31, 1998, and who also underwent psychological, audiological, and speech perception evaluations immediately before and 1 year after implantation. MAIN OUTCOME MEASURE: Scores on the Bayley Scales of Infant Development-Second Edition, Stanford-Binet Intelligence Scale-Fourth Edition, Developmental Profile II, Child Behavior Checklist, speech perception categories, and audiological pure-tone thresholds. RESULTS: Mean (SD) duration of hearing impairment was 37.78 (27.94) months, mean (SD) age at surgery was 50.72 (27.66) months. Significant improvements were found 1 year after surgery in audiological, speech perception, and developmental functioning, but not in nonverbal intelligence or behavior. Greater benefits in audiological and developmental functioning were associated with younger age (<48 months) at implantation. CONCLUSIONS: Patients showed significant improvement in audiological status, overall developmental functioning, and speech perception skills in a short time after surgery. Greatest improvement in speech perception was for children with the least initial impairment, and greatest developmental gains were associated with young age at implantation.

Age Factors↗

PubMed2003

[Implication of cochlear implantation in patients with enlarged vestibular aqueduct syndrome].

OBJECTIVE: To evaluate the intraoperative obstacles and post-operative outcomes of cochlear implantation in children with enlarged vestibular aqueduct syndrome. METHODS: Between May 1995 and June 2002, 10 patients with enlarged vestibular aqueduct syndrome received cochlear implantation in Pekin Union Medical College Hospital. The clinical records of 10 cases of enlarged vestibular aqueduct syndrome were analyzed retrospectively. RESULTS: Via cochleostomy pulsatile clear fluid gusher occurred in 8 cases, which were easily controlled by quickly inserting the electrode array and sealing the cochleostomy with muscle tissue in each instance. The implant was inserted without difficulty in all patients. There have been no post-operatively complications, and audiologic outcome of the 10 patients with cochlear implantation were almost the same as the other patients without inner ear malformations. Five cases of them can even speak better than the other prelingual deafness that may be attributed in part to postlingual deafness. CONCLUSIONS: Despite pulsatile clear fluid gusher in cochlear implantation, no post-operatively complications have been found, and the outcome of these 10 patients with cochlear implantation was excellent. Cochlear implantation can be safely and effectively performed in patients with profound sensorineural hearing loss (SNHL) associated with enlarged vestibular aqueduct syndrome.

Adolescent↗

PubMedDate not supplied

Hearing performance in noise of cochlear implant patients versus severely-profoundly hearing-impaired patients with hearing aids.

It is possible for most post-lingually deaf patients to attain significant open speech recognition following cochlear implantation. In contrast, many severely-profoundly sensorineural hearing-impaired patients receive no benefit from their hearing aids, especially in situations with background noise. The aim of the study was to evaluate the speech recognition ability in quiet and in noise of post-lingually deaf adults implanted with Combi 40/40+ cochlear implants versus severely-profoundly sensorineural hearing-impaired patients fitted with hearing aids. For this purpose, we tested two groups of patients: one that had received cochlear implants (n=22) and a group of subjects with severe-profound sensorineural hearing impairment, fitted with hearing aids (n = 15). All of the patients were tested using the Hochmaier, Schultz, and Moser Discrimination Test in quiet and noise. The results of the study demonstrate that most of our cochlear implant patients received a substantial benefit from their implant, achieving scores of 70 to 100 per cent (mean, 90 per cent) for the numbers test and 10 to 72 per cent (mean, 43 per cent) for the monosyllable test 1 year after implantation. Even in situations with background noise, scores of 1 to 99 per cent (mean, 45.65 per cent) for a signal to noise ratio (SNR) of +15 dB 1 year following the implantation improved to 7 to 95 per cent (mean, 50.7 per cent) at 2 years and 8 to 99 per cent (mean, 60 per cent) at 3 years after implantation. These results are significantly (p<0.04) superior to the hearing aid patients' scores of 1 to 64.2 per cent (mean, 26.7 per cent) for a SNR of 15 dB. The results of the present study may have clinical implications in regard to selection of candidates for cochlear implantation.

Adult↗

PubMed2006

[Multi-channel cochlear implantation in patients with congenital inner ear malformation accompanied middle ear malformation].

OBJECTIVE: To report the multi-channel cochlear implantation in three patients with congenital inner ear malformation accompanied middle ear malformation, including CI surgery and postoperative outcomes of hearing and speech recovery. METHOD: Multi-channel cochlear implantation surgeries have been performed in three cases with congenital inner ear malformation accompanied middle ear malformation in our hospital from May 1995 to May 2002. The transmastoid approach was performed to the cases with congenital inner ear malformation accompanied middle ear malformation. The postoperative sound field hearing tests were taken to the cases three months after the cochlear implantation. RESULT: Multi-channel cochlear implantation was successfully performed in three cases with congenital inner ear malformation accompanied middle ear malformation. The 27, 28, 32 electrodes were inserted respectively in three cases. The intraoperative "Ozze" occurred in three patients. No severe intraoperative and postoperative complications occurred in three cases. All postoperative hearing thresholds were at 35-40 dBHL. CONCLUSION Multi-channel cochlear implantation could be performed in the cases with congenital inner ear malformation accompanied middle ear malformation through the transmastoid approach. The postoperative outcomes were satisfied.

Child↗

PubMed2001

Eighth nerve aplasia and hypoplasia in cochlear implant candidates: the clinical perspective.

OBJECTIVE: To identify the clinical and radiologic characteristics of aplasia and hypoplasia of the eighth nerve. STUDY DESIGN: Retrospective case-note review. SETTING: Cochlear implant program. PATIENTS: All children at the authors' institution in whom the cochlear implant assessment failed because of absence or hypoplasia of the eighth nerve. INTERVENTION: Computed tomography of petrous bones and magnetic resonance imaging of the brain. MAIN OUTCOME MEASURES: Presence or absence of eighth nerve and other radiologic factors contraindicating implantation. RESULTS: Of 143 cochlear implant candidates, 237 were judged ineligible for cochlear implantation. The preimplant assessment failed in 10 candidates of 143 because of bilateral aplasia or hypoplasia of the eighth nerve (7 cases) or unilateral aplasia or hypoplasia of the eighth nerve and a contraindication to operation on the other side (3 cases). The aplasia or hypoplasia of the eighth nerve was confirmed by magnetic resonance imaging in seven cases (5%): six were syndromic (3 CHARGE, 1 VATER-RAPADILLINO, 1 Möbius, 1 Okihiro), and one was nonsyndromic autosomal-recessive. All seven children had delayed motor milestones and absence of auditory brainstem responses. CONCLUSION: Aplasia and hypoplasia of the eighth nerve are not uncommon in pediatric cochlear implant candidates, particularly in the presence of a syndrome such as CHARGE. Magnetic resonance imaging of the brain is mandatory before implantation because it can identify the presence or absence of the eighth nerve. Parents of children with profound hearing loss, delayed motor milestones, absence of auditory brainstem responses, and a syndromic diagnosis, should be made aware of this possible abnormality.

Brain↗

PubMed1996

[Surgery of the cochlear implant: complications].

From 1991 to 1994 13 patients underwent cochlear implant in our Department. The surgical results and complications in this group of patients are reviewed. In all cases the cochlear implant was successful and no major complications were recorded. The most common problems was transient dizziness or imbalance. Other complications were minor facial nerve stimulation during the programming of the device, dehiscence of the suture in the tragal region, problems in the insertion of the electrodes in the scala tympani and a case that needed reimplantation due to technical problems with the device. We consider that a proper selection of cases and a precise surgical technique are essential in order to achieve the adaptation of the cochlear implant and avoid pitfalls.

Adolescent↗

PubMed2006

Post-operative complications of cochlear implantation in adults and children: five years' experience in Maastricht.

Although cochlear implantation is considered a safe method of rehabilitation for profoundly deaf individuals, a number of these patients suffer complications after surgery. To evaluate post-operative complications after cochlear implantation, a retrospective chart review was performed for 112 patients who had undergone implantation in the Maastricht Academic Hospital. Minor complications were defined as those that could be overcome by medical or audiological management. These occurred in 36 patients (32 per cent) and all were managed successfully. Major complications were defined as device extrusion and those requiring further surgery, and these were identified in four patients (3.6 per cent). These complications included wound infection and device failure mediated by middle-ear pathology. In cases of chronic otitis media, we recommend performance of cochlear implantation as a staged procedure. In order to reduce the post-operative incidence of acute otitis media, we recommend adenoidectomy, placement of ventilation tubes and early antibiotic treatment.

Acute Disease↗

PubMed1999

Surgical technique for the CLARION cochlear implant.

This paper describes a technique for implantation of the CLARION Multi-Strategy Cochlear Implant based upon the authors' surgical experience with the device. Although much of the procedure is similar to many commonly performed otologic operations, including implantation of other cochlear prostheses, several device-specific modifications are highlighted. Those modifications include a substantial bony seat, facial recess, and cochleostomy, and the use of an electrode insertion tool.

Cochlea↗

PubMed1996

Initial independent results with the Clarion cochlear implant.

OBJECTIVE: This paper reports some preliminary findings from patients, implanted at the University of Iowa, using the Advanced Bionics Clarion cochlear implant (version 1.0). We compared the performance of patients using both simultaneous analog and nonsimultaneous pulsatile processing strategies. The performance of Clarion patients was also compared with a group of patients who were using either the feature-extraction Nucleus cochlear implant or the compressed-analog Ineraid cochlear implant. DESIGN: One aim was to compare the analog and pulsatile stimulation in 19 patients using the Clarion implant. This aim could be accomplished only partially because of difficulties encountered in adequately fitting patients with the analog strategy. A second aim was to compare the Clarion users' performance with feature-extraction Nucleus and compressed-analog Ineraid patients. Comparisons were made with all patients having 9 mo experience postimplantation. RESULTS: Subjects performed better using the pulsatile mode compared with the analog mode. All subjects chose to use the pulsatile strategy after the first 3 mo of the study. Results comparing performance at 9 mo with our compressed-analog Ineraid and feature-extraction Nucleus patients indicated, in general, better average performance for the Clarion users. CONCLUSIONS: We conclude that the pulsatile version of the Clarion cochlear implant typically produces superior performance to the analog version of that device at this stage in its development. After 9 mo of experience, users of the Clarion implant are performing better than are users of the feature-extraction Nucleus and compressed-analog Ineraid cochlear implants with comparable amounts of experience.

Adult↗

PubMed2005

Relationship between auditory perception skills and mismatch negativity recorded in free field in cochlear-implant users.

This study investigated the ability of cochlear-implanted patients to discriminate tone bursts in free field using the electrophysiological recordings of mismatch negativity (MMN). Seven cochlear-implanted patients (CIP) and eight control subjects (CS) were tested. Event-related potentials were recorded from either 32 or 64 electrodes in response to binaural stimuli using a passive oddball paradigm. Two stimulus-contrast conditions were used to produce MMN: The standard-tone frequency was fixed at 1 kHz, and the deviant-tone frequency was set at 2 or 1.5 kHz. The results show that response waveforms (N1/P2) are similar in latency and amplitude for CS and CIP, suggesting that pure-tone detection is performed over the same time window in both groups. These waveforms are also similar in left- and right-implanted patients, suggesting that electric stimulation of the auditory nerve activates both hemispheres in profound, bilateral hearing loss. Pure-tone audiograms and word-discrimination scores were also measured in each subject in an anechoic room and their relations with MMN data were examined. Correlations were found between the latency of MMN for a 1.5 kHz deviant and the thresholds obtained for pure-tone detection and word discrimination. MMN appears as a possible complementary clinical tool to objectively assess auditory sensitivity in cochlear-implanted populations. However, further improvements are still necessary before it can be used as a standard clinical examination.

Acoustic Stimulation↗

PubMed1995

The mismatch negativity in cochlear implant users.

For individuals with severe or profound hearing loss, electrical stimulation of surviving neural elements by a cochlear implant may partly restore a sensation of hearing. Determining the extent of restoration based on behavioral measures may be difficult, particularly when evaluating young children or individuals who have little or no experience with normal hearing. In normal-hearing individuals, an objective measure of sound discrimination may be obtained by studying the mismatch negativity (MMN) component of the auditory evoked potential. The MMN may be evoked by a number of physical differences in acoustic stimuli including duration and pitch. For cochlear implant users, analogous stimulus differences may be produced by changing the length of a stimulus pulse train or by changing the pair of activated electrodes along a multi-electrode implant array. This paper will provide an overview of our current results, comparing evoked response data recorded from both normal-hearing individuals and cochlear implant users. In both normal-hearing individuals and cochlear implant users, MMNs were evoked by differences in stimulus train duration and pitch (or electrode pair activation in cochlear implant users). These findings suggest that the MMN may be a useful method for assessing the discriminability of electrical stimulation patterns produced by a cochlear implant. Eventually, information gained by MMN testing may yield important information for developing rehabilitation programs for the individual user.

Adult↗

PubMed1999

Direct measurement of cerebrospinal fluid pressure through the cochlea in a congenitally deaf child with Mondini dysplasia undergoing cochlear implantation.

OBJECTIVE: Perilymph/cerebrospinal fluid (CSF) "gushers" may occur at cochleostomy during cochlear implant surgery, particularly in patients with congenital cochlear duct malformation in which CSF in the internal auditory meatus is in direct communication with the perilymphatic space in the cochlea. The object of the study was to measure the pressure and flow of a CSF gusher at cochleostomy. STUDY DESIGN: The design was a preoperative pressure measurement. SETTING: The setting was a multidisciplinary cochlear implant program. PATIENT: A 4-year-old girl with bilateral Mondini deformity undergoing cochlear implantation was studied. INTERVENTION: A size 23 FG intravenous cannula was inserted into the cochlea and connected to a pediatric drip set to form an improvised manometer. MAIN OUTCOME MEASURE: Intracochlear fluid pressure was measured at 14 cm H2O, equivalent to the normal CSF pressure that would be recorded in a child of this age at lumbar puncture. An indirect measurement of the likely size of the CSF/perilymph defect was made. RESULTS: This technique may allow better assessment of the risk of postoperative CSF leakage and meningitis. CONCLUSION: This simple technique of measuring the pressure in a perilymph gusher can be used to assess the need for careful sealing of the cochleostomy, to measure the reduction in pressure produced by head elevation or a spinal drain, and to assess the probable size of a defect in the lamina cribrosa.

Cerebrospinal Fluid Pressure↗

PubMed1986

Rehabilitation concepts with the cochlear implant.

In some ways, it appears that rehabilitation for cochlear implant patients is following the early rehabilitation trends of this century. In the early part of the 1900's, emphasis was on lip-reading, since we did not have amplification as we now know it. With the refinements in amplification, there was less emphasis on analytic lip-reading (exact identification of sounds and words). The trend was to counsel individuals on the benefits and limitations of amplification; lip-reading was regarded as something hearing-impaired individuals would learn anyway. Aural rehabilitation now emphasizes hearing aids. Twenty-five years ago, the emphasis was on lip-reading, with or without amplification. It would appear that rehabilitation for cochlear implant patients is following the same trend. As we learn more about cochlear implants, the trends for rehabilitation will become more clear.

Cochlear Implants↗

PubMed2002

A sensitive period for the development of the central auditory system in children with cochlear implants: implications for age of implantation.

OBJECTIVE: The aim of the present experiment was to assess the consequences of cochlear implantation at different ages on the development of the human central auditory system. DESIGN: Our measure of the maturity of central auditory pathways was the latency of the P1 cortical auditory evoked potential. Because P1 latencies vary as a function of chronological age, they can be used to infer the maturational status of auditory pathways in congenitally deafened children who regain hearing after being fit with a cochlear implant. We examined the development of P1 response latencies in 104 congenitally deaf children who had been fit with cochlear implants at ages ranging from 1.3 yr to 17.5 yr and three congenitally deaf adults. The independent variable was the duration of deafness before cochlear implantation. The dependent variable was the latency of the P1 cortical auditory evoked potential. RESULTS: A comparison of P1 latencies in implanted children with those of age-matched normal-hearing peers revealed that implanted children with the longest period of auditory deprivation before implantation-7 or more yr-had abnormal cortical response latencies to speech. Implanted children with the shortest period of auditory deprivation-approximately 3.5 yr or less-evidenced age-appropriate latency responses within 6 mo after the onset of electrical stimulation. CONCLUSIONS: Our data suggest that in the absence of normal stimulation there is a sensitive period of about 3.5 yr during which the human central auditory system remains maximally plastic. Plasticity remains in some, but not all children until approximately age 7. After age 7, plasticity is greatly reduced. These data may be relevant to the issue of when best to place a cochlear implant in a congenitally deaf child.

Adolescent↗