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Objective: Multi-centre collaborative study to develop and refine the design of a prototype thin perimodiolar cochlear implant electrode array and to assess feasibility for use in human subjects.Study Design: Multi-centre temporal bone insertion studies.Materials and Methods: The modiolar research array (MRA) is a thin pre-curved electrode that is held straight for initial insertion with an external sheath rather than an internal stylet. Between November 2006 and February 2009, six iterations of electrode design were studied in 21 separate insertion studies in which 140 electrode insertions were performed in 85 human temporal bones by 12 surgeons. These studies aimed at addressing four fundamental questions related to the electrode concept, being: (1) Could a sheath result in additional intra-cochlear trauma? (2) Could a sheath accommodate variations in cochlea size and anatomies? (3) Could a sheath be inserted via the round window? and (4) Could a sheath be safely removed once the electrode had been inserted? These questions were investigated within these studies using a number of evaluation techniques, including X-ray and microfluoroscopy, acrylic fixation and temporal bone histologic sectioning, temporal bone microdissection of cochlear structures with electrode visualization, rotational tomography, and insertion force analysis.Results: Frequent examples of electrode rotation and tip fold-over were demonstrated with the initial designs. This was typically caused by excessive curvature of the electrode tip, and also difficulty in handling of the electrode and sheath. The degree of tip curvature was progressively relaxed in subsequent versions with a corresponding reduction in the frequency of tip fold-over. Modifications to the sheath facilitated electrode insertion and sheath removal. Insertion studies with the final MRA design demonstrated minimal trauma, excellent perimodiolar placement, and very small electrode dimensions within scala tympani. Force measurements in temporal bones demonstrated negligible force on cochlear structures with angular insertion depths of between 390 and 450°.Conclusion: The MRA is a novel, very thin perimodiolar prototype electrode array that has been developed using a systematic collaborative approach. The different evaluation techniques employed by the investigators contributed to the early identification of issues and generation of solutions. Regarding the four fundamental questions related to the electrode concept, the studies demonstrated that (1) the sheath did not result in additional intra-cochlear trauma; (2) the sheath could accommodate variations in cochlea size and anatomies; (3) the sheath was more successfully inserted via a cochleostomy than via the round window; and (4) the sheath could be safely removed once the electrode had been inserted. [ABSTRACT FROM AUTHOR]

Acoustic plus electric (electric-acoustic) speech processing has been successful in highlighting the important role of articulation information in consonant recognition in those adults that have profound high-frequency hearing loss at frequencies greater than 1500 Hz and less than 60% discrimination scores. Eighty-seven subjects were enrolled in an adult Hybrid multicenter Food and Drug Administration clinical trial. Immediate hearing preservation was accomplished in 85/87 subjects. Over time (3 months to 5 years), some hearing preservation was maintained in 91% of the group. Combined electric-acoustic processing enabled most of this group of volunteers to gain improved speech understanding, compared to their preoperative hearing, with bilateral hearing aids. Most have preservation of low-frequency acoustic hearing within 15 dB of their preoperative pure tone levels. Those with greater losses (>30 dB) also benefited from the combination of electric-acoustic speech processing. Postoperatively, in the electric-acoustic processing condition, loss of low-frequency hearing did not correlate with improvements in speech perception scores in quiet. Sixteen subjects were identified as poor performers in that they did not achieve a significant improvement through electric-acoustic processing. A multiple regression analysis determined that 91% of the variance in the poorly performing group can be explained by the preoperative speech recognition score and duration of deafness. Signal-to-noise ratios for speech understanding in noise improved more than 9 dB in some individuals in the electric-acoustic processing condition. The relation between speech understanding in noise thresholds and residual low-frequency acoustic hearing is significant (r = 0.62; p < 0.05). The data suggest that, in general, the advantages gained for speech recognition in noise by preserving residual hearing exist, unless the hearing loss approaches profound levels. Preservation of residual low-frequency hearing should be considered when expanding candidate selection criteria for standard cochlear implants. Duration of profound high-frequency hearing loss appears to be an important variable when determining selection criteria for the Hybrid implant. [ABSTRACT FROM AUTHOR]

For some individuals with severe high-frequency hearing loss, hearing aids cannot provide a satisfactory improvement in speech recognition. However, these same patients often have too much residual hearing to qualify as candidates for a cochlear implant. Here we describe results with the Iowa/Nucleus Hybrid cochlear implant, which is designed to preserve the patient's residual low-frequency hearing while at the same time supplementing their high-frequency hearing through electrical stimulation. The advantages of this approach are presented, including improved speech recognition in competing backgrounds as compared with traditional cochlear implants. The results with the Iowa/Nucleus Hybrid device demonstrate the ability of the auditory system to integrate acoustic and electrical stimulation, even under conditions of severe distortions to the normal cochlear place-frequency mapping. [ABSTRACT FROM AUTHOR]

Objective: For vestibular schwannomas (VSs) that require treatment, options are limited to microsurgery or irradiation (IR). Development of alternative therapies that augment or replace microsurgery or IR would benefit patients not suitable for current therapies. This study explored the ability of ErbB2 inhibitors to modulate the effects of IR on VS cells.Study Design: Prospective study using primary cultures derived from human VSs.Methods: Primary cultures of VS cells were derived from acutely resected tumors. Cultures received single escalating doses (15-40 Gy) of gamma-irradiation from a Cs gamma-irradiation source. Cell proliferation was determined by BrdU uptake and apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Trastuzumab (Herceptin) and PD158780 were independently used to inhibit ErbB2 signaling while neuregulin-1beta (NRG-1) was used to activate ErbB2.Results: IR induces VS cell cycle arrest and apoptosis in doses greater than 20 Gy, demonstrating that VS cells are relatively radioresistant. This radioresistance likely arises from their low proliferative capacity as a sublethal dose of IR (10 Gy) strongly induces deoxyribonucleic acid (DNA) damage evidenced by histone H2AX phosphorylation. Inhibition of ErbB2, which decreases VS cell proliferation, protects VS cells from radiation-induced apoptosis, while NRG-1, an ErbB2 ligand and VS cell mitogen, increases radiation-induced VS cell apoptosis.Conclusions: Compared with many neoplastic conditions, VS cells are relatively radioresistant. The radio-protective effect of ErbB2 inhibitors implies that the sensitivity of VS cells to IR depends on their proliferative capacity. These results hold important implications for current and future treatment strategies. [ABSTRACT FROM AUTHOR]

Objective/hypothesis: To evaluate the long-term performance of adult Clarion 1.0 cochlear implant users.Study Design: This was a retrospective, longitudinal study evaluating word discrimination in quiet for 31 adult cochlear implant patients with preimplantation sentence scores of less than 10%.Methods: The length of the study was 135 months with a mean follow-up length of 93 (median, 96) months. For the duration of the study, all subjects used the Clarion 1.0 cochlear implant with speech processors programmed for the use of the continuous interleaved sampling strategy.Results: There was no significant growth or decline in speech perception after 24 months postimplantation unless adverse medical events were experienced. Age at implantation was significantly and substantially negatively correlated (-11% word score per decade, r = 0.68) with most recent score, maximum score, time to maximum score, range of performance, 24- to 130-month mean score, and for any longitudinal data point tested: 3 to 6 months, 6 months, 1 year, 2 years, 5 years, and 10 years. There were no age-related declines in performance. There were no observed correlations between duration of deafness and any of the variables listed above.Conclusions: The lack of correlation between duration of deafness and performance in a cohort without residual hearing suggests the presence of a strong correlation between age and speech performance with a cochlear implant. That the cochlear implant is a safe therapy for the treatment of profound deafness is supported by the stability of scores through the 10-year study period as well as a zero rate of device failures or explantation. [ABSTRACT FROM AUTHOR]

This study examined the growth of expressive language skills in children who received cochlear implants (CIs) in infancy. Repeated language measures were gathered from 29 children who received CIs between 10 and 40 months of age. Both cross-sectional and growth curve analyses were used to assess the relationship between expressive language outcomes and CI experience. A beneficial effect of earlier implantation on expressive language growth was found. Growth curve analysis showed that growth was more rapid in children implanted as infants than those implanted as toddlers. Age at initial stimulation accounted for 14.6% of the variance of the individual differences in expressive language growth rates. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: This study documents the importance of preserving residual low-frequency acoustic hearing as those with more residual hearing are selected for cochlear implantation. Surgical strategies used for hearing preservation with a short hybrid cochlear implant are outlined. The benefits of preserved residual low-frequency hearing, improved word understanding in noise, and music appreciation are described.Study Design: Multicenter, prospective, single-subject design.Methods: Records were reviewed of 21 individuals participating in an Food and Drug Administration (FDA) feasibility clinical trial who have received an Iowa/Nucleus 10 mm electrode. A second group of subjects receiving implants at the University of Iowa that have used the 10 mm device between 2 years and 6 months were also reviewed. Outcome measures included standardized tests of monosyllabic word understanding, spondees in noise, and common melody recognition.Results: Low-frequency hearing was maintained in all individuals immediately postoperative. One subject lost hearing at 2.5 months postoperative after a viral infection. The group has averaged a loss of -9 dB low-frequency acoustic hearing between 125 and 1,000 Hz. Monosyllabic word understanding scores at 6 months for a group being followed for an FDA clinical trial using the implant plus hearing aids was 69% correct. For the long-term group receiving implants at Iowa, monosyllabic word understanding in those who have used the device between 6 months and 2 years is 79%. Other important findings include improved recognition of speech in noise (9 dB improvement) as compared with standard cochlear implant recipients who were matched for speech recognition in quiet and near normal recognition of common melodies.Conclusion: The surgical strategies outlined have been successful in preservation of low-frequency hearing in 96% of individuals. Combined electrical and acoustical speech processing has enabled this group of volunteers to gain improved word understanding as compared with their preoperative hearing with bilateral hearing aids and a group of individuals receiving a standard cochlear implant with similar experience with their device. The improvement of speech in noise and melody recognition is attributed to the ability to distinguish fine pitch differences as the result of preserved residual low-frequency acoustic hearing. Preservation of low-frequency acoustic hearing is important for improving speech in noise and music appreciation for the hearing impaired, both of which are important in real-life situations. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: To provide long-term speech perception and production, educational, vocational, and achievement outcome data for pediatric cochlear implant recipients.Study Design: This is a retrospective study using consecutive referrals of prelingually, profoundly deaf children at the University of Iowa Hospitals and Clinics.Methods: Twenty-seven prelingually deaf young adults who received a cochlear implant between the ages of 2 and 12 years participated. Outcome measures included device-use information, perceptual information, reading results for all participants and educational achievement results for 17 of 27 participants, educational placement information/vocational information for all students, as well as a comparison of the child's educational/vocational outcome with that of the parent's educational/vocational outcome.Results: Speech perception and production scores were highly correlated. Achievement test results indicated that scores were within 1 SD from normative data based on hearing individuals. Over 50% of the college-age eligible students enrolled in college. This initial group of implant users had a nonuse rate of 11% in the first 3 years. Eighty-nine percent of the users maintained full-time use for 7 years, and 71% of this group have maintained full-time use to date.Conclusions: This cohort of cochlear implant users compared favorably with their hearing peers on academic achievement measures. Although there was a wide distribution of educational and vocational outcomes, the children tended to follow the educational/vocational patterns of their parents. As age of implantation decreases, it will be important to compare achievement outcomes of this first generation with those of subsequent generations of cochlear implant users. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: The concept of combining electrical stimulation for high-frequency sound with acoustic hearing for low-frequency information was tested. In addition, whether residual hearing can be preserved when an electrode is placed into the inner ear up to 10 mm and whether place of electrical stimulation influences speech perception were tested.Study Design: A single-subject clinical trial design was employed.Methods: Six postlingual adults with severe high-frequency hearing impairment were recruited to participate in the study. A new six-channel cochlear implant was designed for the clinical trial. The intracochlear electrodes were either 6 or 10 mm in length based on a Nucleus CI-24 multichannel implant. Monosyllabic word understanding and consonant identification testing in a recorded sound-only condition were used to assess changes in speech perception. Follow-up was greater than 12 months.Results: Acoustic hearing was preserved in all six subjects (n = 3, 6-mm electrodes; n = 3, 10-mm electrodes). Preoperative monosyllabic word and sentence scores were unchanged in all subjects following implantation. A 30% to 40% improvement in consonant recognition occurred with the 10-mm electrode. The subjects with 10-mm electrodes were able to understand 83% to 90% of the monosyllabic words using the implant plus binaural hearing aids. Scores were more than doubled when compared with preoperative scores with hearing aids only.Conclusion: The human ear has the capability to integrate both acoustic and high-frequency electrically processed speech information. Placement of a short, 10-mm electrode does not appear to damage residual low-frequency inner ear hair cell function, interfere with the micro mechanics of normal cochlear vibration, or decrease residual speech perception. The improvement in speech recognition was due primarily to the increased perception of higher-frequency consonantal speech cues, and this improvement took several months to become apparent. Such a device can provide a substantial benefit in speech understanding to individuals with severe high-frequency hearing loss, while still maintaining the benefits of the residual lower-frequency acoustic hearing. The position of the electrode and the place of frequency information within the cochlea were shown to be important factors in the success of such a device. [ABSTRACT FROM AUTHOR]

Neuroepithelial cysts are lesions of the central nervous system that have previously been reported in cerebral parenchyma, in the spinal cord, and within the ventricles in association with the choroid plexus. We describe 2 cases of neuroepithelial cysts of the middle ear. One was diagnosed after surgery for a retraction pocket and chronic otitis media complicated by an intraoperative cerebrospinal fluid (CSF) leak. The other produced bilateral spontaneous CSF otorrhea and mimicked the presentation of arachnoid granulations. Both cases were verified with immunohistochemical stains. Neuroepithelial cysts, although rare, should be considered in the differential diagnosis of spontaneous CSF otorrhea or an epitympanic mass. [ABSTRACT FROM AUTHOR]

Presbycusis affects 40-50% of people over age 65, and millions of Americans have other types of hearing loss. You are uniquely situated to detect these problems and guide patients to the best treatment options. [ABSTRACT FROM AUTHOR]

Sixteen experienced cochlear implant patients with a wide range of speech-perception abilities received the SPEAK processing strategy in the Nucleus Spectra-22 cochlear implant. Speech perception was assessed in quiet and in noise with SPEAK and with the patients' previous strategies (for most, Multipeak) at the study onset, as well as after using SPEAK for 6 months. Comparisons were made within and across the two test sessions to elucidate possible learning effects. Patients were also asked to rate the strategies on seven speech recognition and sound quality scales. After 6 months' experience with SPEAK, patients showed significantly improved mean performance on a range of speech recognition measures in quiet and noise. When mean subjective ratings were compared over time there were no significant differences noted between strategies. However, many individuals rated the SPEAK strategy better for two or more of the seven subjective measures. Ratings for 'appreciation of music' and 'quality of my own voice' in particular were generally higher for SPEAK. Improvements were realized by patients with a wide range of speech perception abilities, including those with little or no open-set speech recognition. [ABSTRACT FROM AUTHOR]

This study focused on long-term speech perception performances of 34 prelingually deafened children who received multichannel cochlear implants manufactured by Cochlear Corporation. The children were grouped by the age at which they received cochlear implants and were characterized by the amount of time they used their device per day. A variety of speech perception tests were administered to the children at annual intervals following the connection of the external implant hardware. No significant differences in performance are evident for children implanted before age 5 compared to children implanted after age 5 on closed-set tests of speech perception ability. All children demonstrated an improvement in performance compared to the pre-operative condition. Open-set word recognition performance is significantly better for children implanted before age 5 compared to children implanted after age 5 at the 36-month test interval and the 48-month test interval. User status, defined by the amount of daily use of the implant, significantly affects all measures of speech perception performance except pattern perception. [ABSTRACT FROM AUTHOR]

A 13-month-old cochlear implant recipient underwent routine device activation. Three months postoperatively, the patient sustained a fall with contact to the area of the implant without immediate complication. Ten months postoperatively, the position of the external coil appeared to have moved and the patient did not seem to be responding as well to sound. Audiological testing could not elicit normal device impedances. AP and lateral plain radiographs of the skull revealed migration of the internal magnet from its position within the internal coil to a position over the receiver/stimulator. This is the first known published case of cochlear implant magnet migration. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the performance of the new features of the Nucleus Research Platform 8 (RP8), a system developed specifically for research purposes. The RP8 consists of a research implant, a speech processor and a new NRT software (NRT v4), and includes comparisons of the different artefact-cancellation methods, NRT threshold, and recovery function measurements. The system has new artefact-suppression techniques and new diagnostic capabilities; their performance has been verified in animal experiments. In this study, NRT data were collected from 15 postlingually deafened adult cochlear implant patients intraoperatively and up to 6 months postoperatively after switch-on. The initial investigation in two clinics in Europe focused primarily on the enhanced NRT capabilities. Results from the trial in two European clinics indicate that NRT measurements can be obtained with lower noise levels. A comparison of the different artefact-cancellation techniques showed that the forward-masking paradigm implemented in the Nucleus 3 system is still the method of choice. The focus of this report is on recovery function characteristics, which may give insight into auditory nerve fiber properties with regard to higher stimulation rates. [ABSTRACT FROM AUTHOR]

Forty children with prelingual, profound deafness who received the Nucleus multichannel cochlear implant between the ages of 2 and 13 years participated in this study. The children had an average of 63.3 months (SD=24 months) of experience with their cochlear implants. A majority of the children used simultaneous communication and attended public-school programs at the time of testing. Reading achievement was assessed using the Paragraph Comprehension subtest of the Woodcock Reading Mastery Test-Revised, Form G (1987). This study compared the reading-achievement levels of this group of cochlear-implant users with the results of previous studies of children with profound hearing losses who did not have the benefit of cochlear implants. Results indicated that nearly one half of the children in this study were reading at or within 8 months of their grade level. The reading-grade quotient of .74 was calculated based upon the slope of the regression line for the plot of years in school and reading grade-level achieved. This finding indicates that using a cochlear implant has a positive effect on reading achievement level. [ABSTRACT FROM AUTHOR]