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At least 217 records · Page 12Linked to original sources
PubMed2002

Cochlear implants and brain stem implants.

This chapter describes the development of two implantable prosthetic neurostimulators which, in the last 20 years, have revolutionised the management of severe-to-profound sensorineural deafness. We have witnessed their rapid evolution from the realms of esoteric laboratory abstraction, with many critics and little perceived clinical use, to a routine treatment which is safe, effective and, indeed, cost effective. It is one of the great triumphs of biomedical and surgical collaboration, and is without any doubt the greatest ever advance in the treatment of deafness.

Adult↗
PubMedDate not supplied

Cochlear implant place psychophysics. 2. Comparison of forward masking and pitch estimation data.

Results for forward masking and numerical estimation of pitch were compared in a group of 6 adult subjects implanted with cochlear prostheses manufactured by Cochlear Limited. Data were collected for bipolar + 1 stimulation in all subjects, and for stimulation in one other mode, either common ground or monopolar, for all subjects but one. The pitch data show various irregularities and in each case can be seen to be broadly consistent with the corresponding forward masking data. It is shown that a 'centre of gravity' of the forward masking distribution varies with masker electrode in a manner that is qualitatively very similar to the variation of pitch estimate. It is suggested that, while pitch estimation results are consistent with those from forward masking, the latter contain more detailed information that may be useful in understanding intersubject variations in speech comprehension.

Adolescent↗
PubMed2001

Cochlear implant assessment: imaging issues.

Cochlear implants are electronic auditory prostheses used to rehabilitate deafened persons who have lost their hair cells. They are partly worn externally and partly implanted in the ear. They provide a direct stimulation of the spiral ganglion cells of the cochlear nerve by bypassing the destroyed hair cells. The objectives of this article are to summarise what head and neck surgeons need to know before cochlear implantation and to describe the imaging study protocol used and anomalies to look for. A few explanations are resumed about placement of a brainstem implant.

Brain↗
PubMed2000

Cochlear implant performance in senior citizens.

Cochlear implants are indicated for elderly patients with severe-to-profound hearing loss (sensorineural hearing loss >/=70 dB). Their use has been limited, possibly by the misconception that elderly patients will perform poorly. To document the performance of older adults (> or =65 years old), we undertook a retrospective analysis of our postlingually deafened adult patients who underwent implantation with the CLARION Multi-Strategy Cochlear Implant and underwent formal audiologic analysis (sentence recognition [Central Institute for the Deaf, CID] and monosyllabic word recognition (consonant-noun-consonant, CNC)). Both younger (n = 20; mean age = 46.9 years) and older (n = 16; mean age = 71.5 years) adults showed statistically significant increases in CID and CNC scores after cochlear implantation. No statistically significant difference could be detected in operative time, anesthesia time, length of hospitalization, or CID or CNC scores between the two age groups. We conclude that age should not be a criterion for deciding who should receive cochlear implants.

Adolescent↗
PubMed2005

Dynamics of auditory plasticity after cochlear implantation: a longitudinal study.

Human representational cortex may fundamentally alter its organization and (re)gain the capacity for auditory processing even when it is deprived of its input for more than two decades. Stimulus-evoked brain activity was recorded in post-lingual deaf patients after implantation of a cochlear prosthesis, which partly restored their hearing. During a 2 year follow-up study this activity revealed almost normal component configuration and was localized in the auditory cortex, demonstrating adequacy of the cochlear implant stimulation. Evoked brain activity increased over several months after the cochlear implant was turned on. This is taken as a measure of the temporal dynamics of plasticity of the human auditory system after implantation of cochlear prosthesis.

Acoustic Stimulation↗
PubMedDate not supplied

Cochlear implantation in a patient with osteogenesis imperfecta and otospongiosis.

PURPOSE: We describe the findings in a patient with osteogenesis imperfecta (van der Hoeve syndrome) with otospongiosis who received Nucleus 22-channel (Cochlear Pty, Limited, Australia) cochlear implantation. Cochlear implantation in cases of osteogenesis imperfecta with otospongiosis appears to be extremely rare. The syndrome itself and otospongiosis are both associated with debilitating hearing impairment. METHODS: A female patient who had a triad of brittle bones, blue sclera, and hearing impairment and underwent cochlear implantation was selected for this study. RESULTS: During surgery, otospongiotic feature of hypervascular, reddish middle-ear mucosa was found. While performing cochleostomy, very soft and brittle cochlear bone was noted, which may be the effect of both osteogenesis imperfecta and otospongiosis. CONCLUSION: Although cochlear implantation is not always indicated in cases such as described herein, these patients with profound deafness may benefit from it.

Adult↗
PubMed1998

Cochlear implants: selection criteria and shifting borders.

Cochlear implants have proven to be effective and reliable in postlingually deaf adults. This is also true for congenitally deaf and perilingually deaf children up to the age of six years. Due to the increasing experience, the improvement of implant technology and the proven reliability the selection criteria are broadened with shifting borders. The main extensions are related to age, additional handicaps, residual hearing and special etiologies of deafness. Increasing evidence shows that very early implantation results in better performance and better hearing and speech development. Near-normal language acquisition can be achieved in children implanted under the age of four. Additional handicaps do not automatically exclude a candidate from cochlear implantation. A case-to-case decision has to be made based on additional diagnostics and the experience of the implant centre. A list of suitable handicaps is provided. Severely hearing impaired patients may also be considered for cochlear implantation if their residual hearing provides no benefit for speech discrimination. The same holds true for children. Cochlear implantation in obliterated cochleae and inner ear malformation requires a special surgical technique and special electrode arrays. In this way even difficult cases can be managed with remarkable outcome. Over all, the selection criteria have been broadened with increasing experience and technological improvement. This development may continue and the borderline between hearing aids and cochlear implants will shift further towards severe hearing loss. However, the basis for success still remains good rehabilitation, a team approach and the willingness of the patient to undergo the whole process of cochlear implantation.

Adult↗
PubMed2006

[Performances and complications of cochlear implant in 134 adult patients implanted since 1990].

OBJECTIVE: The aim of this study was to analyse performance of cochlear implants in a retrospective series of adults with postlingually in order to search for predictive factors and identify complications. METHODS: Between 1990 and 2003, 134 adult patients were implanted: 129 patients on one side and 5 patients on both sides. Hearing benefit at 6, 12, 24 and 36 months and performance at 12 months were analyzed as function of the etiology, age at implantation, lipreading and speech coding strategy. RESULTS: Compared to performances before implantation, cochlear implants provided significant and rapid improvement at 6 months (p<0.0001). The results were not correlated with age at implantation, etiology or lipreading ability before implantation. Performances were worse in patients with meningitis (p<0.01), but the percentage of improvement was similar between the different etiologies. Major complications were rare: one case of regressive postoperative facial nerve weakness. CONCLUSION: Cochlear implants provide significant and rapid improvement, with low morbidity. Results are not correlated with age at implantation, etiology or lipreading ability.

Adolescent↗
PubMed2006

High resolution micro-CT scanning as an innovative tool for evaluation of the surgical positioning of cochlear implant electrodes.

X-ray microtomography (micro-CT) is a new technique allowing for visualization of the internal structure of opaque specimens with a quasi-histological quality. Among multiple potential applications, the use of this technique in otology is very promising. Micro-CT appears to be ideally suited for in vitro visualization of the inner ear tissues as well as for evaluation of the electrode damage and/or surgical insertion trauma during implantation of the cochlear implant electrodes. This technique can greatly aid in design and development of new cochlear implant electrodes and is applicable for temporal bone studies. The main advantage of micro-CT is the practically artefact-free preparation of the samples and the possibility of evaluation of the interesting parameters along the whole insertion depth of the electrode. This paper presents the results of the first application of micro-CT for visualization of the inner ear structures in human temporal bones and for evaluation of the surgical positioning of the cochlear implant electrodes relative to the intracochlear soft tissues.

Artifacts↗
PubMed2002

Speech understanding in quiet and noise in bilateral users of the MED-EL COMBI 40/40+ cochlear implant system.

OBJECTIVE: The purpose of the study was to investigate speech understanding in quiet and noise in subjects bilaterally implanted with multi-channel cochlear implants. DESIGN: Nine adults bilaterally implanted with MED-EL implants were included in the study. The subjects were tested in three conditions: with both implants, with the right implant only, and with the left implant only. Speech tests included monosyllables in quiet and sentences in noise (10 dB signal to noise ratio). Speech was presented from the front, and noise was presented from either 90 degrees or 270 degrees azimuth. RESULTS: All subjects reported benefit from bilateral stimulation. Speech scores for all subjects were higher with bilateral than with unilateral stimulation. The average score across subjects for sentence understanding was 31.1 percentage points higher with both cochlear implants compared with the cochlear implant ipsilateral to the noise, and 10.7 percentage points higher with both cochlear implants compared with the cochlear implant contralateral to the noise. The average score for recognition of monosyllabic words was 18.7 percentage points higher with both cochlear implants than with one cochlear implant. All of these differences in average scores were significant at the 5% level. CONCLUSIONS: Bilateral cochlear implantation provides a significant benefit in speech understanding in both quiet and noise.

Acoustic Stimulation↗
PubMed1997

[Conservation of residual hearing after cochlear implantation].

Indications for cochlear implantation have been expanded to include severely hearing impaired adults and may increase the number of patients presenting with preoperative residual hearing. Conservation of residual hearing may allow better performance with an implant. However, conventional thought is that implantation destroys auditory structures involved in residual hearing. This study was undertaken to assess if there are general or surgical factors intervening in the conservation of residual hearing in a sample of multichannel implant recipients. A retrospective study on 50 adult cochlear recipients with preoperative residual hearing has been undertaken. Sixteen of 50 implanted subjects (32%) were found to have conserved their residual hearing. Among them, seven patients have clinically non-significant changes of hearing. Age, side of implantation, gender and etiology did not influence the outcome of residual hearing. Round window ossification, ossification of the cochlea, length of insertion, approach and site of insertion (scala tympani vs.scala vestibuli) were not found to be statistically significant between the population having lost and the population having conserved residual hearing. This study emphasizes the need to undertake a larger multicenter longitudinal study to determine the existence of factors related to the conservation of residual hearing.

Adolescent↗
PubMed2004

Blood flow in the ears of patients receiving cochlear implants.

We measured cochlear blood flow (CBF) in 55 patients who received cochlear implants, using a laser-Doppler probe placed over the site of drilling in the cochlear bony wall. The subjects included 29 patients with congenital deafness of unknown cause, 8 with idiopathic progressive sensorineural hearing loss, 4 with postmeningitic deafness, 3 with Waardenburg's syndrome, 3 with congenital cytomegalovirus infection, and 8 whose deafness had other causes. There was a wide range of CBF values in patients with congenital deafness of unknown cause. In the patients with idiopathic progressive sensorineural hearing loss, the CBF was significantly lower in patients more than 40 years old. Intracochlear calcification following meningitis appears to be associated with a reduced CBF.

Adolescent↗
PubMed2004

Measuring progress in children with autism spectrum disorder who have cochlear implants.

OBJECTIVE: To quantify progress after cochlear implantation for children with autism spectrum disorder (ASD). STUDY DESIGN: Retrospective review of speech and language and speech perception test scores of children with autism who have received a cochlear implant at our center. SETTING: University of Michigan Medical Center, Cochlear Implant Program. PATIENTS: Six children, ages 3 to 16 years, who received cochlear implants at the our center. All children were diagnosed as having ASD by a neuropsychologist, either before or after receiving a cochlear implant. MAIN OUTCOME MEASURES: Children participated in preoperative and postoperative speech and language and speech perception testing. A survey was administered to parents to evaluate subjective impressions of cochlear implant benefit and quality of life before and after implantation. RESULTS: Improved scores were recorded for children on whom standardized expressive and receptive vocabulary testing was possible. Children who could not complete standardized tests demonstrated improvement in raw scores. Improvement on the Meaningful Auditory Integration Scale was noted for the 4 of 7 children who completed the scale preoperatively and postoperatively. Survey results suggested changes in responsiveness to sound, interest in music, vocalization, and eye contact following implantation. Five of the 6 families indicated that they would recommend a cochlear implant to another family in a similar situation. CONCLUSIONS: Gains made by children in our study were small compared with the general implant population; however, when compared with themselves preoperatively, these children did demonstrate progress. Improvements in behaviors and interaction point to a quality of life benefit following implantation that is difficult to quantify.

Autistic Disorder↗
PubMed2001

Cochlear implants in children.

Cochlear implants are electronic prostheses that provide a high quality sense of hearing to severely and profoundly deaf children and adults. As improvements in surgical technique and device performance have occurred, indications for implantation have expanded.

Child↗
PubMed2000

Assessment of aided ABR thresholds before cochlear implantation.

The Nottingham Paediatric Cochlear Implant Programme (NPCIP) specializes in the cochlear implantation of children under the age of 5 years. The initial stage in the pre-implant evaluation process is audiological assessment. In complex paediatric cases, behavioural audiological assessment may be difficult. In such cases, an objective measure to verify the aided hearing threshold is desirable. This study compares unaided and aided hearing thresholds, by both objective and behavioural techniques, in 20 children (aged <1-10 years). Objective data were collected from auditory brainstem responses (ABR) and behavioural thresholds were measured by use of developmental age-appropriate tests. When comparing the unaided ABR click threshold to the behavioural threshold (obtained from the average of 1-4 kHz warble tones) the ABR threshold was, on average, 9 dB lower (more sensitive). Using the same comparison for aided responses a difference of <5 dB was observed. Unaided ABR thresholds resulted in 35% of subjects responding to the click stimulation (when using a maximum stimulation level of 105 dB nHL), whereas introducing aided ABR measurement elicited positive results in 75% of subjects. The effect of the hearing aid on the stimulus was measured by use of a 2 cc coupler which was connected to a precision sound level meter, whose AC output was recorded onto digital audiotape. Analysis of the resultant output spectra in the frequency domain highlighted signal non-linearity and distortion when using high-intensity stimuli with moderate to high aid gains. In conclusion, aided ABR thresholds are valuable in the management of young children. However, when performing either ABR or behavioural aided hearing threshold measurements it is essential to be aware of the limitations of the hearing aid and the stimulus.

Acoustic Impedance Tests↗
PubMedDate not supplied

Maturation of the mismatch negativity: effects of profound deafness and cochlear implant use.

The use of cochlear implants to restore auditory sensation in deaf children is increasing, with a trend toward earlier implantation. However, little is known about how auditory deprivation and subsequent cochlear implant use affect the maturing human central auditory system. Our previous studies have demonstrated that the obligatory auditory evoked potentials (AEPs) of implanted children are very different from those of normal-hearing children. Unlike the obligatory potentials, which primarily reflect neural responses to stimulus onset, the mismatch negativity (MMN) provides a neurophysiological measure of auditory short-term memory and discrimination processes. The purpose of this investigation is to review our studies of the effects of auditory deprivation due to profound deafness and cochlear implant use on the maturation of the MMN in children, placed in the context of overall age-related changes in the AEPs. The development and application of a statistical technique to assess the MMN in individuals is also reviewed. Results show that although the morphology of the obligatory AEPs is substantially altered by the absence of a normal N(1) peak, the MMN is robustly present in a group of implanted children who have good spoken language perception through their device. Differences exist in the scalp distribution of the MMN between implanted and normal-hearing children. Specifically, the MMN appears to be more symmetrical in amplitude over both hemispheres, whereas it is initially much larger over the contralateral hemisphere in normal-hearing children. These findings suggest that, compared to N(1), the MMN is a better measure of basic auditory processes necessary for the development of spoken language perception skills in profoundly deaf children and adults who use a cochlear implant.

Adult↗
PubMed1992

Sensory aids in conjunction with cochlear implants.

The use of cochlear implants in profoundly hearing-impaired individuals can restore varying degrees of auditory capabilities. Although very little auditory information is transmitted to these patients through amplification systems, we hypothesized that some of the cues obtained from sensory aids might be helpful when used in conjunction with the cochlear implant postoperatively. Eight patients implanted at NYU Medical Center, Bellevue Hospital Center, have used some sensory aid in addition to the Nucleus multichannel cochlear prosthesis. All subjects were evaluated using standard auditory tests including pure-tone and speech audiometry, portions of the Minimal Auditory Capabilities (MAC), Speech Pattern Contrast Perception (SPAC), Iowa test batteries; and the Early Speech Perception (ESP), Word Intelligibility by Picture Identification (WIPI), and Glendonald Auditory Screening Procedure (GASP), where appropriate. Subjects were evaluated under three conditions: implant alone, implant plus sensory aid, and sensory aid alone. Results indicate that the interaction between a multichannel cochlear implant and a sensory aid can provide some improved performance for adult implanted patients (i.e., they do better under the dual condition than in the implant-alone condition). Variables such as thresholds in the nonimplanted ear and usage time can affect the outcome.

Adult↗