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PubMedDate not supplied

Improved auditory performance of cochlear implant patients using the middle fossa approach.

The preliminary results of insertion of a cochlear implant via the middle fossa in nine patients with profound bilateral hearing loss are described. Aetiologies included a bilateral radical mastoidectomy cavity, adhesive otitis media, autoimmune inner ear disease, previous cranial trauma, genetic pre-lingual deafness, and otosclerosis. A classic middle fossa approach was adopted. A small cochleostomy measuring 1.5 mm in diameter was performed on the most superficial part of the basal turn. A Nucleus 24M cochlear implant system (Cochlear Corporation) was inserted in four patients, a Lauraflex implant (Philips Hearing Implants) was used in three patients and a Combi 40+ (Med-el) with a double electrode array in two. Single electrode arrays were inserted from the cochleostomy to the cochlear apex and occupied a portion of the basal turn, as well as the middle and apical turns. Double electrode arrays were inserted, one towards the apex and one into the basal turn of the cochlea towards the round window. The receiver stimulator was positioned in a bone well previously drilled in the temporal squama and the electrode carrier was inserted in the fenestrated cochlea. The activity of the inserted electrodes was tested by means of telemetry and intraoperative recording of electrically evoked auditory brainstem responses (EABR). Speech recognition tests, performed over a period of time ranging from one to six months after cochlear implant activation, yielded better results in these patients compared with those obtained in postlingually deaf patients operated on via the traditional transmastoid route. Cochlear implant insertion via the middle fossa approach is a technique which is suitable for the implantation of patients with bilateral radical mastoidectomy cavities, chronic middle ear disease, middle ear malformations, or with partial obliteration of the cochlea in the basal turn. However, the main advantage of inserting the implant through the middle fossa cochleostomy consists in the possibility of stimulating, with the single array, areas of the cochlea, i.e. part of the basal, middle and apical turns, where a greater survival rate of spiral ganglion cells is known to occur. In addition, with the double array total occupation of the cochlea is possible, providing the possibility of replicating the tonotopic organization of the cochlea. This new approach has led to major improvements in speech recognition in all patients compared with patients operated on via the transmastoid approach and, given the present state of the art, may be the elective approach for optimal implantation outcomes.

Adolescent↗

PubMed2000

Belfast Cochlear Implant Centre; the surgical results of the first 100 implants.

We assess the surgical results of the first one hundred cochlear implant operations at the Belfast Cochlear Implant Centre. This paper is in the form of a retrospective case series, taking into account the surgical technique used and any problems encountered. Initially 28 operations were performed using the standard inverted U-shaped incision. After Gibson and Harrison described a vertical postaural incision we began using a slight modification of this technique for any further implantations. Since November 1994 the vertical post aural skin incision has been used in 71 patients. The surgical complications of cochlear implantation include haematoma, wound infection and flap necrosis of varying degrees of severity. We report a low level of these complications, particularly with the vertical incision.

Adolescent↗

PubMed1990

[Cochlear implants in 1990].

The various techniques of cochlear implantation are described. Implants may be divided into mono- and multi-electrode and into intra- and extra-cochlear. Cochlear implants are indicated only in patients with total or deep bilateral deafness with residual fibres still functioning in the acoustic nerves. Intra-cochlear multi-electrode implants are the most sophisticated ones and usually provide better performances than those observed with mono-electrode implants.

Adult↗

PubMed2005

Evaluating cochlear implant trauma to the scala vestibuli.

OBJECTIVES: Placement of cochlear implant electrodes into the scala vestibuli may be intentional, e.g. in case of blocked scala tympani or unintentional as a result of trauma to the basilar membrane or erroneous location of the cochieostomy. The aim of this study was to evaluate the morphological consequences and cochlear trauma after implantation of different cochlear implant electrode arrays in the scala vestibuli. DESIGN: Human temporal bone study with histological and radiological evaluation. SETTING: Twelve human cadaver temporal bones were implanted with different cochlear implant electrodes. Implanted bones were processed using a special method to section undecalcified bone. MAIN OUTCOME MEASURES: Cochlear trauma and intracochlear positions. RESULTS: All implanted electrodes were implanted into the scala vestibuli using a special approach that allows direct scala vestibuli insertions. Fractures of the osseous spiral lamina were evaluated in some bones in the basal cochlear regions. In most electrodes, delicate structures of the organ of Corti were left intact, however, Reissner's membrane was destroyed in all specimens and the electrode lay upon the tectorial membrane. In some bones the organ of Corti was destroyed. CONCLUSIONS: Scala vestibuli insertions did not cause severe trauma to osseous or neural structures, thus preserving the basis for electrostimulation of the cochlea. However, destruction of Reissner's membrane and impact on the Organ of Corti can be assumed to destroy residual hearing.

Cadaver↗

PubMed1990

Advantages and disadvantages reported by some of the better cochlear-implant patients.

An open-ended questionnaire was administered to 53 of some of the better patients using five different kinds of cochlear implants. The subjects listed the advantages and disadvantages of their cochlear implant. Patients were asked about the time from implantation until maximum benefit and effect of the cochlear implant on tinnitus. Advantages were reported in (1) speech perception when speechreading can be used (85%); (2) environmental sound perception (75%); (3) psychologic effects (70%); (4) speech perception when speechreading cannot be used (64%); (5) lifestyle and social effects (42%); and (6) speech production (32%). Disadvantages were reported in (1) use of equipment (79%); (2) environmental-sound perception (47%); (3) speech perception when speechreading may be used (17%); (4) psychologic effects (11%); (5) speech perception when speechreading is not used (9%); (6) lifestyle and social effects (3.8%); and (7) speech production (1.9%). Ninety-one percent of the subjects indicated that they achieved maximum benefit in the first 7 months of cochlear-implant use. Eighty-one percent of the subjects with tinnitus indicated that the cochlear implant had a positive effect on their tinnitus. In 17 percent of the cases the cochlear implant had no effect on their tinnitus and in 2 percent of the cases it made the tinnitus worse.

Adolescent↗

PubMed2006

A retrospective study of cochlear implant outcomes in children with residual hearing.

BACKGROUND: There has been increasing demand for the cochlear implantation of children who demonstrate some auditory capacity with conventional hearing aids. The purpose of this study was to examine speech recognition outcomes in a group of children who were regarded as borderline candidates for cochlear implantation as their residual hearing and/or auditory functioning levels exceeded typical audiologic candidacy criteria. METHODS: A retrospective chart review was undertaken at one Canadian cochlear implant centre to identify children implanted at age 4 or older with a pure-tone-average of 90 dB or better and speech recognition of 30% or greater. Pre-implant and post-implant open-set word and sentence test scores were analyzed. RESULTS: Eleven children of 195 paediatric cochlear implant recipients met the inclusion criteria for this study. Speech recognition results for the 10 English-speaking children indicated significant gains in both open-set word and sentence understanding within the first 6 to 12 months of implant use. Seven of 9 children achieved 80% open-set sentence recognition within 12 months post-surgery. CONCLUSION: Children with several years of experience using conventional amplification demonstrated rapid progress in auditory skills following cochlear implantation. These findings suggest that cochlear implantation may be an appropriate intervention for selected children with severe hearing losses and/or auditory capacity outside current candidacy criteria.

Journal Article↗

PubMed1995

An unusual cause of cochlear implant failure.

We present a cochlear implant failure previously unidentified and unreported. Following successful implantation and activation of a Cochlear Mini 22 system, a distressing barrage of crackling noises was heard by the patient despite repeated programming with threshold and comfort level adjustment. The implant soon became nonfunctional and integrity testing showed deficient electrical responses and abnormal surface measured wave forms. Investigation of the explant, following reimplantation with an identical system, showed a defective trim capacitor, an electric component of the internal circuit in the stimulator. Paired Student's t-test showed a marginally significant increase (p = 0.047) in effective threshold level and a highly significant decrease (p = 0.0002) in maximum comfort level for the second implant compared to the first implant.

Cochlear Implants↗

PubMed2004

Head shadow, squelch, and summation effects in bilateral users of the MED-EL COMBI 40/40+ cochlear implant.

OBJECTIVE: The aim of the study was to investigate the impact of bilateral cochlear implant use on speech perception in noise in bilateral users of the MED-EL COMBI 40/40+ cochlear implants. DESIGN: Speech reception thresholds were measured in 21 subjects using the Oldenburg sentence test. Speech was always presented from the front. Noise was either presented from the front, from the left side, or from the right side. Each condition was measured for unilateral and bilateral implant use. RESULTS: For three subjects, the test was too difficult to be administered. The 18 subjects from whom a complete data set could be obtained showed a significant head shadow effect and summation effect for all test conditions, whereas the squelch effect was significant for noise from the left side only. Average effect sizes were significant for all effects and amounted to 6.8 dB for the head shadow effect, 0.9 dB for the squelch effect, and 2.1 dB for the summation effect. Effect sizes were not correlated with duration of deafness. CONCLUSIONS: Bilateral cochlear implant users can at least qualitatively benefit from the effects that are known from normal-hearing subjects, that is, head shadow, summation, and squelch effect. Bilateral cochlear implantation also reduces the performance gap between cochlear implant users and normal-hearing subjects.

Adolescent↗

PubMed2004

Sensitivity to interaural level and envelope time differences of two bilateral cochlear implant listeners using clinical sound processors.

OBJECTIVES: To assess the sensitivity of two bilateral cochlear implant users to interaural level and time differences (ILDs and ITDs) for various signals presented through the auxiliary inputs of clinical sound processors that discard fine timing information and only preserve envelope cues. DESIGN: In a lateralization discrimination experiment, the just noticeable difference (JND) for ILDs and envelope ITDs was measured by means of an adaptive 2-AFC method. Different stimuli were used, including click trains at varying repetition rates, a speech fragment, and noise bursts. For one cochlear implant listener and one stimulus, the sensitivity to envelope ITDs was also determined with the method of constant stimuli. The dependency of ILD-JNDs on the interaural place difference was studied with stimulation at single electrode pairs by using sinusoidal input signals in combination with appropriate single-channel processor fittings. In a lateralization position experiment, subjects were required to use a visual pointer on a computer screen to indicate in-the-head positions for blocks of stimuli containing either ILD or ITD cues. All stimuli were loudness balanced (before applying ILD) and fed directly into the auxiliary inputs of the BTE processors (TEMPO+, Med-El Corp.). The automatic gain control and the processors' microphones were deactivated. RESULTS: Both cochlear implant listeners were highly sensitive to ILDs in all broadband stimuli used; JNDs approached those of normal-hearing listeners. Pitch-matched single electrode pairs showed significantly lower ILD-JNDs than pitch-mismatched electrode pairs. Envelope ITD-JNDs of cochlear implant listeners obtained with the adaptive method were substantially higher and showed a higher test-retest variability than waveform ITD-JNDs of normal-hearing control listeners and envelope ITD-JNDs of normal-hearing listeners reported in the literature for comparable signals. The envelope ITD-JNDs for the click trains were significantly lower than for the speech token or the noise bursts. The best envelope ITD-JND measured was ca. 250 mus for the click train at 100 cycles per sec. Direct measurement of the psychometric function for envelope ITD by the method of constant stimuli showed discrimination above chance level down to 150 micros. The lateralization position experiment showed that both ILDs and envelope ITDs can lead to monotonic changes in lateral percept. CONCLUSIONS: The two cochlear implant users tested showed strong effects of ILDs in various broadband stimuli with respect to JNDs as well as lateralization position. The high dependency of ILD-JNDs on the interaural pitch difference suggests the potential importance of pitch-matched assignment of electrodes in the two ears by the speech processors. Envelope ITDs appear to be more ambiguous cues than ILDs, as reflected by the higher and more variable JNDs compared with normal-hearing listeners. The envelope ITD-JNDs of cochlear implant listeners depended on the stimulus.

Acoustic Stimulation↗

PubMed2003

Vestibular dysfunction after cochlear implantation.

OBJECTIVE: To determine the prevalence, symptom characteristics, and potential risk factors for vestibular symptoms after cochlear implantation. STUDY DESIGN: Case-control study design embedded within an ongoing cohort of patients undergoing implantation. SETTING: Academic medical center cochlear implant research program funded by the National Institutes of Health. PATIENTS: Seventy five eligible consecutive patients undergoing cochlear implantation. INTERVENTION: Medical record review. MAIN OUTCOME MEASURE: Recorded symptoms of vestibular symptoms after cochlear implantation. Subjects with vestibular symptoms were considered case subjects; those without vestibular symptoms were considered control subjects. RESULTS: Twenty-nine of 75 (39%) patients experienced dizziness postoperatively. Four patients experienced a single, transient acute vertigo attack occurring less than 24 hours after surgery. The majority, 25 patients, experienced delayed, episodic onset of vertigo. The median (interquartile range) time of delayed onset was 74 (26-377) days after implantation. Delayed dizziness manifested as spontaneous episodic or positional vertigo. Preoperative dizziness, age at implantation, and age at onset of hearing loss were significantly greater in the dizzy group. Preoperative electronystagmography did not differentiate between groups. CONCLUSIONS: Thirty-nine percent (29/75) of subjects with implants were dizzy after implantation. The majority of subjects experienced dizziness in a delayed episodic fashion. Dizziness was not related to implant activation. It seemed that delayed dizziness was not related to immediate surgical intervention but could result from chronic changes occurring in the inner ear; there was some suggestion this could take the form of endolymphatic hydrops.

Acute Disease↗

PubMed1997

Psychological characteristics of child cochlear implant candidates and children with hearing impairments.

OBJECTIVE: To describe the psychological status of deaf children with hearing parents who were seeking a cochlear implant and to compare them with deaf children with hearing parents who were not seeking a cochlear implant. DESIGN: A sample of children consecutively referred for a cochlear implant at the University of Iowa Hospitals and Clinics was contrasted on a number of standardized psychological measures with a cohort of children from Boys Town National Research Hospital, who had hearing impairments and whose families had not sought a cochlear implant. RESULTS: Although the comparison group evidenced more externalizing and social problems than the implant group, the means of both groups fell well within the normal range. Similarly, although mothers of the implant group rated their child's home as characterized by more positive and supportive interactions than did mothers of the children in the comparison group, both group means were well within the average range. On measures of intelligence, the two groups also did not differ. CONCLUSION: Overall, the study indicated that children with hearing impairments and their families who were seeking cochlear implants are not significantly different from children with hearing impairments whose parents were not seeking a cochlear implant. The results provided no support for the notion that children with hearing impairments from families seeking a cochlear implants for their child evidence more behavioral deviance than children with hearing impairments whose parents have not sought an implant.

Adolescent↗

PubMed2000

[Results and experiences with 55 cochlear implantations].

INTRODUCTION: The etiology of deafness in deaf people is defects in the cochlea hair cells. Cochlear implant treatment gives deaf born and patients with acquired deafness the possibility to reestablish or obtain hearing by electric stimulation of the cochlear nerve. In this paper the results of treatment of 35 adults and 20 children are reported. METHOD: The candidates for cochlear implant treatment are extensively investigated before the decision is made to operate. The operative treatment takes place under general anaesthesia and the operative technique is outlined. In the treatment of the deaf, different types of implants and stimulation strategies have been used. The effect of treatment is considered by hearing test and evaluation of speech. RESULTS: Nine of the adults obtained a hearing quality that made using a telephone possible. Almost all adults can by the combination of cochlear implant and lip reading perform a normal conversation. The results in the deaf born children are obtained slowly as the deaf born have to develop hearing and speech from zero. All the treated children have improved possibilities of communication. DISCUSSION: Cochlear implant treatment of deaf people now seems well established both internationally and nationally in Denmark. Cochlear implant equipment has improved considerably throughout the past years and that it today is possible to establish hearing in deaf born or patients with acquired deafness can be considered as one of the greatest developments in otology, maybe the greatest.

Adolescent↗

PubMed2002

Morphometric changes in the cochlear nucleus in patients who had undergone cochlear implantation for bilateral profound deafness.

We have investigated the morphometric changes in the cochlear nucleus of patients who had undergone cochlear implantation following profound deafness. The brain stems of 11 adult patients who had undergone implantation and four non-implanted control cases with varying degrees of hearing loss were studied. The volumes of the ventral cochlear nucleus (VCN) and dorsal cochlear nucleus (DCN), and the maximal cross-sectional area and densities of cell bodies in the anterior ventral cochlear nucleus (AVCN) were measured bilaterally by light microscopy assisted by the Neurolucida 2000 image analysis system. In addition, the density of synapses on cells of the AVCN were estimated using immunostaining for the synaptosome-associated protein (SNAP-25) by light microscopy. There was no significant difference in volumes of VCN and DCN, maximal cross-sectional area and density of cell bodies of the AVCN, and SNAP-25 immunostaining between the cochlear nucleus ipsilateral and contralateral to cochlear implantation. In addition, there was no significant correlation between these morphometric parameters and clinical performance. Peripheral deafness seems to reduce the size of neurons in the AVCN in that the maximum diameter of cell bodies was greater in the ear with better hearing preoperatively (chi-square test P<0.05). However, electrical stimulation provided by the cochlear implantation did not alter these morphometric changes in adult cochlear implant patients.

Aged↗

PubMed2004

Perfusion SPECT in cochlear implantation and promontory stimulation.

BACKGROUND: Recent studies of profoundly deaf patients with cochlear implants have demonstrated that these patients are able to process sound in the auditory cortex in a similar way to normal subjects. However, there are large variations in outcome. Various clinical criteria are used for subject selection and the decision as to which ear is to be implanted involves electrical stimulation of the promontory which is used to confirm the persistence of auditory neurones and fibres that can be utilized by the cochlear implant. In this study we have used SPECT with Tc-HMPAO to investigate activation of the auditory cortex in cochlear implantees post-surgery. In addition we also investigated whether electrical stimulation of the promontory does produce change in blood flow in the auditory cortex in pre-surgery candidates, which would indicate viable auditory networks that can be utilized by a cochlear implant device. METHODS AND RESULTS: Image analysis was performed with SPM99. Results of a simple subtraction paradigm indicated bilateral activation of auditory cortex and Wernicke's area in the post-implant group during auditory stimulus (speech) and bilateral activation of the ventral lateral posterior thalamus and bilateral auditory association cortex BA21/22/42, in the pre-implant group during electrical stimulus but no activation of the primary auditory cortex. A conjunction analysis used to investigate the common areas of activation across both groups during the stimulus condition showed that there was a common bilateral activation of the primary auditory cortex in both groups (BA22/41/42). In addition, analysis of a subset of the seven post-implant subjects who did not comprehend the speech in our study showed an activation (Pu<0.05, where Pu is the peak voxel threshold, uncorrected for multiple comparisons) in the left auditory cortex that extended into area BA22 synonymous with Wernicke's area. This supports the theory that this region has a sensory role.

Adult↗

PubMed2004

Cochlear implant outcomes in the elderly.

OBJECTIVE: This study aimed to review cochlear implantation with respect to surgical and auditory outcomes in subjects aged 70 years and older. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral centers. PATIENTS: Sixty-five patients aged 70 years or older at the time of implantation were compared to a group of patients aged <70 years. INTERVENTION: Patients underwent multichannel cochlear implantation with either the Clarion or Nucleus device. MAIN OUTCOME MEASURE: Presence or absence of surgical complications and auditory performance with open-set word and sentence recognition testing. RESULTS: In patients implanted at age 70 or older, significant improvement in speech understanding was demonstrated in performance scores using Consonant Nucleus Consonant words, Central Institute for the Deaf sentences, and Hearing in Noise Test sentences at 3, 6, and 12 months when compared to preimplantation scores. However, their performance was slightly poorer when compared to a control group of patients <70 years of age in the same measures at 3, 6, and 12 months. CONCLUSIONS: The elderly population showed significant improvement in auditory performance tests following cochlear implantation compared to their preimplantation scores but performed less well than younger patients.

Adult↗

PubMed2002

Performance of cochlear implant recipients with GJB2-related deafness.

Congenital profound hearing loss affects 0.05-0.1% of children and has many causes, some of which are associated with cognitive delay. For prelingually-deafened cochlear implant recipients, the etiology of deafness is usually unknown. Mutations in GJB2 have been established as the most common cause of heritable deafness in the United States. In this report, we identify cochlear implant recipients with GJB2-related deafness and examine the performance of these individuals. Cochlear implant recipients received a battery of perceptive, cognitive, and reading tests. Neither subjects nor examiners knew the etiology of deafness in these individuals. The implant recipients were then examined for mutations in GJB2 using an allele-specific polymerase chain reaction assay, single-strand conformation polymorphism analysis, and direct sequencing. GJB2 mutations were the leading cause of congenital deafness among the cochlear implant recipients screened. Cochlear implant recipients with GJB2-related deafness read within one standard deviation of hearing controls better than other congenitally deaf cochlear implant recipients and non-cochlear implant recipients. Individuals with congenital deafness should be offered GJB2 screening. Positive results establish an etiologic diagnosis and provide prognostic, genetic, and therapeutic information. Effective rehabilitation for profoundly deaf individuals with GJB2-related deafness is possible through cochlear implantation.

Adolescent↗

PubMed1990

Trends in rehabilitation after cochlear implantation.

Although postimplant rehabilitation is generally considered to be an important aspect of a cochlear implant program, the literature reports widely varying practices in the implementation of such programs. The National Institutes of Health consensus statement on cochlear implantation (May 1988), while recognizing that aural rehabilitation facilitates maximal use of the implant, offers no specific guidelines or recommendations. A questionnaire survey was made of over 200 otolaryngologists to determine current practices in a variety of aspects of their cochlear implant programs. Results were obtained from a total of more than 1400 patients, including adults, adolescents, and children. Rehabilitation is an integral part of the cochlear implant program in the vast majority of active programs surveyed. General aspects of cochlear implant programs, as well as those of rehabilitation programs in particular, are discussed.

Adolescent↗

PubMed2001

Cochlear implants: is there any relationship between stimulation rates and adaptation?

OBJECTIVE: To determine the relationship between stimulation rate and adaptation in cochlear implant users. STUDY DESIGN: A prospective clinical study. SETTING: This study was conducted at Hacettepe University Medical Faculty, which is a tertiary care and cochlear implant center in Ankara, Turkey. PATIENTS: Seven patients (three women, four men) who were using Nucleus CI 24 M cochlear implants (Cochlear Corp., Lane Cove, NSW, Australia). Two of them had become deaf after developing language skills, and five had congenitally deafness. RESULTS: Six patients demonstrated no tone decay. Only one patient, who had congenital hearing loss, demonstrated tone decay at stimulation rates of 250, 500, 720, 900 pulses per second. There is no statistically significant relationship between the stimulation rate and the selected electrode. CONCLUSION: The majority of the cochlear implant patients sustained the perception of a continuous electrical signal for 1 minute at 5 to 10 current levels above threshold.

Adaptation, Physiological↗