Faculty Bibliography

In previous works, the authors showed that using robot-assisted steerable electrode array insertions can significantly reduce the insertion forces compared to non-steerable electrode arrays. In addition to steering the electrode array, it is possible to change its angle of approach with respect to the scala tympani. This paper focuses on determining the relevance of changing the angle of approach of the electrode array by comparing steerable electrode array insertions using a two Degrees-of-Freedom (DoF) robot versus a four DoF robot. Optimal insertion path planning strategies are presented for both two and four DoF insertions. Simulation results and experiments show that the four DoF insertions can improve over two DoF insertions. Moreover, changing the angle of approach can further reduce the insertion forces. The simulation results also provide the workspace requirements for designing a custom parallel robot for robot-assisted cochlear implant surgery

OBJECTIVE: Emerging evidence in auditory neuroscience suggests that central auditory pathways process speech asymmetrically. In concert with left cortical specialization for speech, a 'right-ear advantage' in speech perception has been identified. The purpose of this study is to determine if this central asymmetry in speech processing has implications for selecting the ear for cochlear implantation. STUDY DESIGN: Retrospective cohort study. SETTING: Academic university medical center PATIENTS: One hundred one adults with bilateral severe-to-profound sensorineural hearing loss INTERVENTION: Cochlear implantation with the Nucleus 24 Contour device. MAIN OUTCOME MEASUREMENTS: Patients were divided into two groups according to the ear implanted. Results were compared between left-ear- and right-ear-implanted patients. Further subgroup analysis was undertaken, limited to right-handed patients. Postoperative improvement on audiograms and scores on speech perception tests (Hearing in Noise test, City University of New York in quiet and in noise test, Consonant-Vowel Nucleus- Consonant words, and phonemes) at 1 year was compared between groups. Analysis of covariance was used to control for any intergroup differences in preoperative characteristics. RESULTS: The groups were matched in age, duration of hearing loss, duration of hearing aid use, percentage implanted in the better hearing ear, and preoperative audiologic testing. Postoperatively, there were no differences between left-ear- and right-ear-implanted patients in improvement on speech recognition tests. CONCLUSION: Despite central asymmetry in speech processing, our data do not support a right-ear advantage in speech perception outcomes with cochlear implantation. Therefore, among the many factors in choosing the ear for cochlear implantation, central asymmetry in speech processing does not seem to be a contributor to postoperative speech recognition outcomes

OBJECTIVES: Ear anomalies and deafness are associated with CHARGE syndrome, which also presents with a cluster of features including coloboma of the eye, heart defects, atresia of the choanae, developmental retardation, and genitourinary abnormalities. The aim of this study is to explore the viability of cochlear implantation in children with CHARGE syndrome and to assess the outcome. STUDY DESIGN: Retrospective chart review. METHODS: Eleven children presenting with severe to profound sensorineural hearing loss associated with CHARGE syndrome were the subjects of this study. Routine audiometric measurements and the Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS) were performed pre- and postoperatively. In addition, the degree of the subjects' cochlear deformity were measured and correlated to outcome. RESULTS: All patients had varying degrees of ear anomalies, seven patients suffered from coloboma of the eyes, two had heart defects, five exhibited choanal atresia, eleven showed developmental retardation, and six had genitourinary abnormalities. Ten of the children underwent cochlear implantation with complete insertion of the electrode array without complication and were followed over a 3-month to a 7-year period. The eleventh child was not implanted because of severe retardation. All of the implanted children showed varying, but limited degrees, of auditory benefit as measured by routine audiometry and the IT-MAIS. CONCLUSIONS: Careful treatment planning for children with sensorineural hearing loss and CHARGE syndrome can lead to varying, but limited degrees, of auditory benefit with no increase in surgical complications. Although the implant enhanced the children's 'connectivity' to the environment, it did not promote the development of oral language skills in this population

CONCLUSION: Neither speech understanding nor frequency discrimination ability was better in Nucleus Contour users than in Nucleus 24 straight electrode users. Furthermore, perimodiolar electrode placement does not result in better frequency discrimination. OBJECTIVES: We addressed three questions related to perimodiolar electrode placement. First, do patients implanted with the Contour electrode understand speech better than with an otherwise identical device that has a straight electrode? Second, do these groups have different frequency discrimination abilities? Third, is the distance of the electrode from the modiolus related to frequency discrimination ability? SUBJECTS AND METHODS: Contour and straight electrode users were matched on four important variables. We then tested these listeners on CNC word and HINT sentence identification tasks, and on a formant frequency discrimination task. We also examined X-rays and measured the distance of the electrodes from the modiolus to determine whether there is a relationship between this factor and frequency discrimination ability. RESULTS: Both speech understanding and frequency discrimination abilities were similar for listeners implanted with the Contour vs a straight electrode. Furthermore, there was no linear relationship between electrode-modiolus distance and frequency discrimination ability. However, we did note a second-order relationship between these variables, suggesting that frequency discrimination is worse when the electrodes are either too close or too far away from the modiolus

Penetrating trauma to the face and upper zone III of the neck may present unique challenges when the parotid gland and associated neurovascular structures are involved. We report a case of massive hemorrhage from penetrating neck trauma that necessitated emergency parotidectomy for vascular exposure. Facial nerve repair was also necessary, underscoring the importance of this approach not only for successful vascular control but also for preservation of nearby vital structures. The management of penetrating trauma to the parotid region,and relevant anatomy, are discussed

OBJECTIVE: Perimodiolar electrode arrays were developed in an attempt to improve stimulation of specific neural populations and to decrease electrical thresholds, thereby decreasing power consumption. Postoperative radiographs show that coiling of the arrays is variable. Our previous study explored the relationship between the angle of coiling, threshold levels, and functional outcomes using the Nucleus Contour electrode array. This study compares coiling angle, electrical threshold levels, and speech perception measures with the Nucleus Contour Advance electrode array implanted using the new advance off stylet technique versus the Nucleus Contour electrode array implanted using the standard technique. STUDY DESIGN: Retrospective review. SETTING: University medical center. PATIENTS: Forty-two adults and children with normal cochlear anatomy implanted with the Nucleus CI24RCA electrode using the advance off stylet technique with at least 1-year follow-up. INTERVENTION: Therapeutic. MAIN OUTCOME MEASURES: Computer-aided radiographic analysis of perimodiolar electrode placement, electrical threshold measurements, and speech perception outcome measures at 1 year postimplantation. RESULTS: The degree of modiolar coiling was tighter using the new electrode and technique in comparison with standard insertion technique using the Nucleus Contour electrode array. The tighter coiling tended to result in higher electrical thresholds. Lower speech perception outcome measures tended to correlate with a higher degree of coiling. CONCLUSION: The Nucleus Contour Advance electrode array combined with the advance off stylet technique resulted in a more consistent perimodiolar position. However, the tighter coiling resulted in statistically significant increased electrical thresholds and decreased speech perception outcomes. This finding may be secondary to multiple factors, not just coiling angle

OBJECTIVE: Sensorineural hearing loss resulting from otosclerosis, meningitis, chronic otitis media, autoimmune ear disease, and trauma can be associated with partial or total obstruction of the cochlear scalae. Multichannel cochlear implantation may be difficult in a cochlea with an obstructed scala tympani. The purpose of this study is to determine the safety and efficacy of scala tympani electrode insertion. STUDY DESIGN: Retrospective chart review. SETTING: Academic medical center. PATIENTS: Eight children and adults with profound sensorineural hearing loss who underwent cochlear implantation with known scala vestibuli electrode array insertion were subjects for this study. INTERVENTIONS: Eight study subjects underwent implantation: five with the Nucleus 24RCS (Contour) device and three with the Nucleus 24M device. OUTCOME MEASURES: Imaging findings, operative findings, and age-appropriate speech perception testing. RESULTS: All patients had full electrode insertion. Various obstructive patterns on computed tomography and magnetic resonance imaging were found, and there was a range of speech perception results. All but one patient improved based on age-appropriate monosyllabic word and sentence tests. CONCLUSION: Scala vestibuli multielectrode insertion is a viable alternative when scala tympani insertion is not possible because of abnormal anatomy or anatomical changes secondary to disease or previous implantation. We will also present an algorithm of options for decision making for implantation when encountering cochlear obstruction and difficult electrode insertion