Development and Validation of the Cochlear Implant Surgical Competency Assessment Instrument.

OBJECTIVE: We present a new instrument for evaluation of cochlear implant (CI) surgical skills and review its validation process. METHODS: An instrument to assess CI surgical competency incorporated results of structured surveys of comprehensiveness sent to 30 international CI experts and US trainees. One-hundred evaluations of 28 residents, fellows, and practicing CI surgeons were completed. Surgical skills were evaluated by four experienced neurotologists (two raters per subject) using two temporal bones per subject. A training session was completed by 24 subjects between the first and second procedure. Comparison of two blinded rater's scores per subject provided information on interrater reliability. Correlation of competency scores with degree of training and with improvement after a training session provided information on construct validity. RESULTS: High levels of interrater reliability were confirmed by using the intraclass correlation coefficient. Construct validity was demonstrated by correlation of higher performance scores with increasing years of training, board certification, and fellowship training. Construct validity is also supported by improvement in scores after a CI training session as well as by acceptability surveys. DISCUSSION: Data indicate that this instrument is an objective, accurate, and dependable procedure-specific instrument for evaluating CI surgical competency. CONCLUSION: The cochlear implant surgical competency assessment (CI-SCA) can be used to establish CI surgical competency, identify surgical skills that require remediation and demonstrate progress during training.

Cochlear Implantation in Children With Autism Spectrum Disorder.

OBJECTIVE: To assess the outcome of cochlear implantation in children with autism spectrum disorder (ASD). STUDY DESIGN: Retrospective case review and survey. SETTING: Tertiary referral center. PATIENTS: Children who meet criteria for cochlear implantation and diagnosis of ASD. MAIN OUTCOME MEASURES: Receptive and expressive language scores and parental survey data. RESULTS: Fifteen patients with history of ASD and cochlear implantation were analyzed and compared with 15 patients who received cochlear implant and have no other disability. Postoperatively, more than 67% of children with ASD significantly improved their speech perception skills, and 60% significantly improved their speech expression skills, whereas all patients in the control group showed significant improvement in both aspects. The top 3 reported improvements after cochlear implantation were name recognition, response to verbal requests, and enjoyment of music. Of all behavioral aspects, the use of eye contact was the least improved. Survey results in regard to improvements in patient interaction were more subtle when compared with those related to sound and speech perception. The most improved aspects in the ASD patients' lives after cochlear implantation seemed to be attending to other people's requests and conforming to family routines. Of note, awareness of the child's environment is the most highly ranked improvement attributed to the cochlear implant. CONCLUSION: Cochlear implants are effective and beneficial for hearing impaired members of the ASD population, although development of language may lag behind that of implanted children with no additional disabilities. Significant speech perception and overall behavior improvement are noted.

Biomedical engineering principles of modern cochlear implants and recent surgical innovations.

This review covers the most recent clinical and surgical advances made in the development and application of cochlear implants (CIs). In recent years, dramatic progress has been made in both clinical and basic science aspect of cochlear implantation. Today's modern CI uses multi-channel electrodes with highly miniaturized powerful digital processing chips. This review article describes the function of various components of the modern multi-channel CIs. A selection of the most recent clinical and surgical innovations is presented. This includes the preliminary results with electro-acoustic stimulation or hybrid devices and ongoing basic science research that is focused on the preservation of residual hearing post-implantation. The result of an original device that uses a binaural stimulation mode with a single implanted receiver/stimulator is also presented. The benefit and surgical design of a temporalis pocket technique for the implant's receiver stimulator is discussed. Advances in biomedical engineering and surgical innovations that lead to an increasingly favorable clinical outcome and to an expansion of the indication of CI surgery are presented and discussed.

fMRI evaluation of cochlear implant candidacy in diffuse cortical cytomegalovirus disease.

Congenital cytomegalovirus infection is the most frequent nongenetic cause of pediatric hearing loss in the United States, affecting approximately 8,000 children each year. Due in part to variable cytomegalic involvement of the auditory cortex, cochlear implantation outcomes have varied widely. Functional magnetic resonance imaging (fMRI) has the potential to assist in determining candidacy for cochlear implantation through the detection of intact auditory pathways including the cortex. We report a case of a 21-month-old girl with cytomegalovirus-related deafness and diffuse white matter involvement in which fMRI was a determining factor for cochlear implantation and side selection.

Influence of DFNB1 status on expressive language in deaf children with cochlear implants.

OBJECTIVE: The objective of this study was to compare the language growth of children with connexin-related deafness (DFNB1) who received cochlear implants versus the language growth of implanted children with non-DFNB1 deafness. STUDY DESIGN: A prospective longitudinal observational study and analysis. SETTING: Two tertiary referral centers. PATIENTS: There were 37 children with severe-to-profound hearing loss who received cochlear implants before the age of 5 years. INTERVENTIONS: A standardized language measure, the section for expressive language of the Reynell Developmental Language Scale was used to assess expressive language skills at 2 times postimplantation (14 and 57 mo postimplantation). Molecular screening for DFNB1 gene variants. MAIN OUTCOME MEASURES: Language quotient (LQ) scores (i.e., age-equivalent score obtained on the Reynell Developmental Language Scale divided by the child's chronological age), results of genotyping. RESULTS: The mean language age at the second time interval (mean ± standard deviation, 51.8 ± 13 mo) was greater than at the first testing session (mean ± standard deviation, 19 ± 8 mo, p < 0.001, Wilcoxon signed rank test). When divided by genotype, DFNB1 children exhibited a higher LQ and less variability in scores than non-DFNB1 children at the second testing interval (Wilcoxon sign rank test, p = 0.0034). A regression analysis (linear-fit by least squares) conducted on 26 children with preimplantation audiometric data showed that DFNB1 status was the independent variable with greater predictive effect on LQ at the second testing interval, followed by age at implantation (R2 = 0.35, p = 0.0479). CONCLUSION: Deaf children who received cochlear implants before the age of 5 years and use oral communication show substantial improvement in language abilities. In this study, DFNB1 children who use cochlear implants show greater gains in expressive language than non-DFNB1 children, independent of residual hearing, age at implantation, and duration of implant use.

The perceived angle of the round window affects electrode insertion trauma in round window insertion - an anatomical study.

CONCLUSION: In this study round window (RW) insertion of cochlear implant was performed with a lower degree of trauma in 86.6% of cases. Therefore RW insertion is a valid option to be considered in selected cochlear implant patients, especially when hearing preservation is a goal. In most cases drilling of the overhangs is required. OBJECTIVES: To systematically examine the potential for minimizing electrode insertion trauma with RW insertion. METHODS: Fifteen temporal bones were inserted with a 0.5 mm electrode analog in an anterior or antero-inferior vector from a reference point along the facial recess. Surface preparation of the inferior segment of the basal turn was performed and the point of first contact was analyzed using computerized morphometric software. The same software was used to measure the RW dimensions before and after drill down of the bony overhangs. An insertion was considered 'traumatic' if the point of first contact was the medial wall of the scala, whereas 'less traumatic' was an insertion in which the point of first contact was the inferior or posterior wall of the scala. RESULTS: Less traumatic insertion was achieved in 13 of the 15 bones, and in these the mean RW angle, as observed from a surgical point of view, was 137°. The mean RW angle in the traumatic insertion group was 147°. The difference was statistically significant.

International classification of reliability for implanted cochlear implant receiver stimulators.

OBJECTIVE: To design an international standard to be used when reporting reliability of the implanted components of cochlear implant systems to appropriate governmental authorities, cochlear implant (CI) centers, and for journal editors in evaluating manuscripts involving cochlear implant reliability. STUDY DESIGN: The International Consensus Group for Cochlear Implant Reliability Reporting was assembled to unify ongoing efforts in the United States, Europe, Asia, and Australia to create a consistent and comprehensive classification system for the implanted components of CI systems across manufacturers. SETTING: All members of the consensus group are from tertiary referral cochlear implant centers. INTERVENTIONS: None. MAIN OUTCOME MEASURE: A clinically relevant classification scheme adapted from principles of ISO standard 5841-2:2000 originally designed for reporting reliability of cardiac pacemakers, pulse generators, or leads. RESULTS: Standard definitions for device failure, survival time, clinical benefit, reduced clinical benefit, and specification were generated. Time intervals for reporting back to implant centers for devices tested to be "out of specification," categorization of explanted devices, the method of cumulative survival reporting, and content of reliability reports to be issued by manufacturers was agreed upon by all members. The methodology for calculating Cumulative survival was adapted from ISO standard 5841-2:2000. CONCLUSION: The International Consensus Group on Cochlear Implant Device Reliability Reporting recommends compliance to this new standard in reporting reliability of implanted CI components by all manufacturers of CIs and the adoption of this standard as a minimal reporting guideline for editors of journals publishing cochlear implant research results.

Cochlear implantation in common forms of genetic deafness.

Genetic factors are among the main etiologies of severe to profound hearing loss and may play an important role in cochlear implantation (CI) outcomes. While genes for common forms of deafness have been cloned, efforts to correlate the functional outcome of CIs with a genetic form of deafness carried by the patient have been largely anecdotal to date. It has been suggested that the differences in auditory performance may be explained by differences in the number of surviving spiral ganglion cells, etiology of hearing loss, and other factors. Knowledge of the specific loci and mutations involved in patients who receive cochlear implants may elucidate other factors related to CI performance. In this review article, current knowledge of cochlear implants for hereditary hearing loss will be discussed with an emphasis on relevant clinical genotype-phenotype correlations.

Conservation of hearing and protection of auditory hair cells against trauma-induced losses by local dexamethasone therapy: molecular and genetic mechanisms.

HYPOTHESIS: Dexamethasone (DXM) protects hearing against trauma-induced loss. MATERIALS: in vivo: A guinea pig model of electrode induced trauma (EIT)-induced hearing loss was used to locally deliver dexamethasone. In vitro: TNF-α-challenged organ of Corti explants treated with DXM or polymer-eluted DXM +/- PI3K/Akt/PkB/NFkB inhibitors were used for hair cells count and gene expression studies. RESULTS: in vivo: local DXM treatment of EIT-animals prevents trauma-induced loss of ABR thresholds that occurs in EIT-animals and EIT-animals treated with the carrier solution (i.e., AP), and prevented loss of auditory hair cells. In vitro: DXM and polymer-eluted DXM were equally effective in protecting hair cells from ototoxic levels of TNF-α Inhibitor treated explants demonstrated that DXM treatment requires both Akt/PKB and NFkB signalling for otoprotection. DXM treatment of explants showed up regulation of anti-apoptosis related genes (i.e., Bcl-2, Bcl-xl) and down regulation of pro-apoptosis related genes (i.e., Bax, TNFR-1). CONCLUSIONS: DXM exert its otoprotective action by activation of cell signal molecules (e.g., NFkB) that alter the expression of anti- and pro-apoptosis genes.

Mechanisms of hearing loss from trauma and inflammation: otoprotective therapies from the laboratory to the clinic.

This article reviews a series of in vitro and in vivo studies that examined the otoprotective efficacy of locally delivered dexamethasone and explored the mechanisms by which dexamethasone protects auditory hair cells. These studies used auditory threshold testing in response to pure tone stimuli, organ of Corti explant cultures, FITC-phalloidin-stained explants, and surface preparations to determine hair cell density, osmotic pump delivery of dexamethasone into the scala tympani, an animal model of electrode insertion trauma (EIT)-induced hearing loss, and real-time RT-PCR studies of gene expression levels. Local delivery of two different formulations of dexamethasone conserved hearing and protected hair cells in an animal model of cochlear implantation. Dexamethasone treatment protected hair cells in organ of Corti explants exposed to an ototoxic level of an inflammatory cytokine, and gene expression studies showed that this protection was accomplished by increased expression levels of anti-apoptosis genes (e.g. Bcl-2) and decreased levels of pro-apoptosis genes (e.g. Bax). We conclude that dexamethasone is an effective otoprotective drug for both the conservation of hearing and preservation of hair cells against trauma-induced losses. Locally delivered dexamethasone is a promising therapeutic approach for the conservation of hearing during the process of cochlear implantation.

The temporalis pocket technique for cochlear implantation: an anatomic and clinical study.

OBJECTIVE: To describe the surgical anatomy and clinical outcomes of a technique for securing cochlear implant receiver/stimulators (R/S). Receiver/stimulators are generally secured by drilling a custom-fit seat and suture-retaining holes in the skull. However, rare intracranial complications and R/S migration have been reported with this standard method. Newer R/S designs feature a low profile and larger, rigid flat bottoms in which drilling a seat may be less appropriate. We report a technique for securing the R/S without drilling bone. STUDY DESIGN: Anatomic: Forty-eight half-heads were studied. Digital photography and morphometric analysis demonstrated anatomic boundaries of the subpericranial pocket (t-pocket). Clinical: Retrospective series of 227 consecutive Cochlear implant recipients implanted during a 2-year period using either the t-pocket or standard technique. The main outcome measures were rates of R/S migration and intracranial complications. Minimum follow-up was 12 months. RESULTS: The t-pocket is limited anteriorly by dense condensations of pericranium anteriorly at the temporal-parietal suture, posteroinferiorly at the lamdoid suture, and anteroinferiorly by the bony ridge of the squamous suture. One hundred seventy-one subjects were implanted using the t-pocket technique and 56 using the standard technique, with a minimum follow-up of 12 months. There were no cases of migration or intracranial complications in either group. CONCLUSION: The t-pocket secures the R/S with anatomically consistent strong points of fixation while precluding dural complications. There were no cases of migration or intracranial complication noted. Further trials and device-specific training with this technique are necessary before it is widely adopted.

Cochlear implant surgery in patients more than seventy-nine years old.

OBJECTIVES/HYPOTHESIS: To evaluate the surgical complications, auditory performance, and hearing handicap following cochlear implantation in patients greater than 79 years of age. STUDY DESIGN: Retrospective trial, tertiary referral center. METHODS: The study group was comprised of 21 patients implanted after 79 years of age from 1996 through 2006 with follow-ups past their 8th decade. Pre-op evaluation consisted of pure-tone audiometry and speech discrimination scores (Hearing in Noise Test and City University of New York sentence test). The results of these tests were compared to similar tests taken post-op. A validated hearing handicap questionnaire was used to evaluate the outcome. RESULTS: There were no permanent medical or surgical complications. However, two patients developed exacerbations of previous comorbid conditions (i.e., urinary retention and acute delirium). Implanted patients experienced a significant improvement in audiologic performance, post-op pure tone average, and post-op speech scores (P < .001). A majority of them were able to use the phone and reported that the cochlear implant was of great benefit to them. The post-op hearing handicap inventory for the elderly demonstrated a significant decrease of hearing handicap scores. CONCLUSIONS: This is the first study to focus on a patient group this advanced in age. With increasing life expectancy, we should begin to stratify risk versus benefit of cochlear implantation in this age group. Cochlear implantation improved audiologic performance and the quality of life in patients older than 79 years old. There were no permanent medical or surgical complications. Chronic pain and temporary vertigo were the most common complications reported in this elderly group. Laryngoscope, 2009.

Incidence and indications for revision cochlear implant surgery in adults and children.

OBJECTIVES/HYPOTHESIS: To identify the incidence of and common causes for cochlear implant revision. STUDY DESIGN: Retrospective case series. METHODS: Operative records were reviewed for all cases of revision cochlear implantation from 1992 to 2006. The causes for reimplantation were classified as hard device failure, soft device failure, exposure/infection, receiver/stimulator migration, and electrode migration. Manufacturers' failure analysis of explanted devices was likewise determined. RESULTS: Eight hundred and six cochlear implants were performed during the study period including 44 (5.5%) revision procedures. The revision rate was 7.3% for children and 3.8% for adults and reached statistical significant difference. The most common reasons for revision were device failure (78%; 55% hard failure, 23% soft failure) followed by electrode migration (9%) and receiver/stimulator migration (7%). Manufacturers' analysis of failed devices revealed loss of hermetic seal and cracked cases to be the most common causes of failure. Bench analysis of 5/10 explanted devices that were soft failures demonstrated identifiable device defects. CONCLUSIONS: Revision cochlear implant surgery is an infrequent occurrence. Its incidence appears to be higher in children than in adults, although in this series does not appear to be due to increased wound complications, infections, or trauma. Explanted implants that have soft failure as the etiology may have demonstrable defects on bench testing.

Biopolymer-released dexamethasone prevents tumor necrosis factor alpha-induced loss of auditory hair cells in vitro: implications toward the development of a drug-eluting cochlear implant electrode array.

HYPOTHESIS: Polymer-eluted dexamethasone (DXM) will retain its ability to protect against tumor necrosis factor alpha (TNFalpha)-induced hair cell (HC) loss. BACKGROUND: TNFalpha has been shown to be associated with trauma-induced hearing loss. DXM has been demonstrated to protect the cochlea against trauma-induced hearing loss. DXM is currently administered either systemically or locally to treat patients with sudden hearing loss of unknown cause. METHODS: P-3 organ of Corti explants challenged with an ototoxic level of TNFalpha was the experimental system, and the base form of DXM (DXMb) incorporated into a biorelease polymer (i.e., SIBS) was the otoprotection molecule tested. The efficacy of otoprotection was determined by counts of fluorescein isothiocyanate-phalloidin-stained HCs and changes in gene expression. RESULTS: HC counts show 1) SIBS alone did not protect HCs from TNFalpha ototoxicity (SIBS versus SIBS + TNFalpha; p < 0.001), and 2) SIBS with DXMb provides a significant level of protection against TNFalpha-induced loss of HCs (TNFalpha + SIBS versus TNFalpha + SIBS/DXMb, 299 mug; p < 0.001). Gene expression results show that polymer-eluted DXMb 1) upregulates antiapoptotic genes (i.e., Bcl-2, Bcl-xl) and downregulates a proapoptotic gene (i.e., Bax) in TNFalpha-challenged explants and 2) downregulates TNFR1 in these explants. CONCLUSION: Polymer-eluted DXMb retains its otoprotection capabilities in our in vitro test system of TNFalpha-challenged organ of Corti explants by altering the pattern of gene expression to favor survival of TNFalpha-exposed HCs. These results, although in vitro, support the application of polymer containing DXMb to electrode arrays for the conservation of hearing during cochlear implantation.

Dexamethasone base conserves hearing from electrode trauma-induced hearing loss.

OBJECTIVE/HYPOTHESIS: Local treatment of the cochlea after electrode insertion trauma with dexamethasone base conserves hearing against trauma-induced loss. STUDY DESIGN: Laboratory animal study. METHODS: A guinea pig model of electron insertion trauma (EIT)-induced hearing loss (HL) used 44 guinea pigs sub-divided into four groups: 1) unoperated, controls (Controls, n = 44); 2) EIT, untreated (EIT, n = 15); 3) EIT plus artificial perilymph (EIT + AP, n = 15); and 4) EIT plus dexamethasone base (EIT + DXMb, n = 14). Cochleae that received EIT were randomly selected with contralateral, unoperated cochleae as internal controls. Auditory brainstem responses (ABRs) in response to 0.5 to 16 kHz pure tones were obtained before surgery, immediately after surgery (0 day), and on post-EIT days 3, 7, 14, and 30. Hair cell counts were obtained from stained organ of Corti specimens from all four groups (n = 3/group). Data were analyzed using analysis of variance and a Tukey-Kramer honestly significant difference post hoc test with significance alpha set at <0.05 (hearing) and <0.001 (hair cells). RESULTS: There were significant differences (<0.05) between the ABR thresholds of unoperated (control) and contralateral operated (experimental) ears of EIT and of EIT + AP groups for all tested frequencies. There was no statistical difference (>0.05) in ABR thresholds in the EIT + DXMb versus control groups for 0.5 to 4 kHz tones. DXMb treatment protected hair cells from EIT-induced damage and loss while AP treatment did not. CONCLUSION: The absence of significant differences in hearing thresholds between the EIT + DXMb group and control ears in response to 0.5 to 4 kHz tones demonstrates that DXMb is as effective as the aqueous form of dexamethasone in conserving hearing against EIT-induced loss.