An Animal Model for Cochlear Implants

Abstract

To test the feasibility of using the deaf white cat model of early-onset deafness. We studied the neuronal effects of prosthetic intervention with a clinical, "offthe-shelf" multichannel cochlear implant. Methods: We placed cochlear implants in 5 deaf white kittens at age 12 and 24 weeks. The devices were activated and stimulated in the laboratory using a clinical speech processor programmed with a high-resolution continuous interleaved sampling (CIS) strategy for 8 to 24 weeks. Stimulus parameters were guided by electrically evoked brainstem responses and intracochlear-evoked potentials. Kittens were assessed with respect to their tolerance and general behavior in response to speech, music, and environmental sounds. Results: Surgical complications were minimal, and kittens tolerated the experimental procedures well. Subjects were able to detect and respond to a specific sound played from a computer speaker. Electrophysiologic responses were reliably attainable and showed consistency with observed behavioral responses to sound. This experimental paradigm, using clinical devices, can be used in a practical research setting in cats. Conclusions: Deafness and other variations in neural activity result in many distinct changes to the central auditory pathways. Animal models will facilitate assessment of the reversibility of deafness-associated changes at the level of the neuron and its connections. Our observations of the feasibility of using clinical devices in animal models will enable us to simulate clinical conditions in addressing questions about the effects of "replacement" activity on the structure and function within the central auditory pathways in deafness.

Objective and subjective evaluations of the Nurotron Venus cochlear implant system via animal experiments and clinical trials

“…The positive peaks of the EABRs in the cat experience were similar to those reported in a study by Kretzmer et al [16] in which Clarion II high-focus implants from the Advanced Bionics Corporation CI that were manufactured with smaller 6-electrode arrays for use in cats were examined. The waveforms of the EABR revealed that the Nurotron Õ Venus TM Cochlear Implant System was able to effectively stimulate the feline auditory system.…”

Silicone-Coated Thin Film Array Cochlear Implantation in a Feline Model

“…Previously published feline implantation techniques were used (2,6,7). Approval was obtained from both the Georgia Regents University, and the Georgia Institute of Technology Institutional Animal Care and Use Committees.…”

“…Surgical approach was modeled after previously published feline studies by Rajguru et al, (2) Kretzmer et al, (6) and Kirby and Middlebrooks (7). One of 2 surgeons performed each insertion.…”

“…Before implantable devices can be used as human prostheses, however, function, efficacy, and safety must be documented in an animal model. Several previous studies have noted successful cochlear implantation in cats, with reliably observed responses to sound and the ability to elicit evoked auditory brainstem responses (2,5,6). …”

The Effect of Cochlear-Implant-Mediated Electrical Stimulation on Spiral Ganglion Cells in Congenitally Deaf White Cats

“…Three normal-hearing cats (one white and two pigmented), seven congenitally deaf white cats, and eight congenitally deaf white cats with unilateral cochlear implants were used. The implanted cats have contributed unrelated data to other studies (Kretzmer et al 2004;Ryugo et al 2005;O'Neil et al 2010). Spiral ganglion cell counts were also used from cats whose numbers were previously published by others (n=4, Howe 1934;n=1, Gacek and Rasmussen 1961;n=54, Mair 1973).…”