Cochlear implants are designed to restore auditory perception to patients with severe to profound sensorineural hearing loss. CLARION, the only cochlear implant system manufactured in the United States, has eight independent output circuits that enable flexibility in speech processing and a spiral shaped modiolar-hugging electrode. Recent studies suggest that CLARION patients using bipolar simultaneous analog strategies perform at higher levels, have higher impedance values and lower threshold and comfort levels, than do patients using monopolar sequential schemes. It has been hypothesized that the electrode in these patients is in close proximity to the modiolus, allowing a focused bipolar electric field while positioning the array near the spiral ganglion cells. Advanced Bionics has designed a new electrode system that improves channel selectivity by enabling consistent placement of the electrode near the modiolus. The handling properties and ability of this electrode to achieve modiolar proximity and greater insertion depth will be evaluated in temporal bones using fluoroscopy and 3-D CT scan reconstruction. If these aims are accomplished, the safety of the electrode system will be studied in animal models and then evaluated functionally in human subjects. The goal of this research is to achieve improved speech recognition by providing greater selectivity of stimulation, thereby expanding processing options and allowing an even greater percentage of implant recipients to function normally in a hearing environment.
As cochlear implants have gained acceptance as a rehabilitative tool patient selection criteria have become less restrictive, the cochlear implant market has experienced a tremendous expansion estimated at 30% per year. The wide range of patient performance is a major impediment to further acceptance and market expansion. The modiolar- hugging electrode system offers a mechanism for decreasing performance variability by enabling selective stimulation and, thereby, providing improved hearing. A provisional patent application has been filed and technical information in this proposal is considered proprietary.
