title: Auditory outcomes following implantation and electrical stimulation of the semicircular canals.
abstract: We measured auditory brainstem responses (ABRs) in eight Rhesus monkeys after implantation of electrodes in the semicircular canals of one ear, using a multi-channel vestibular prosthesis based on cochlear implant technology. In five animals, click-evoked ABR thresholds in the implanted ear were within 10 dB of thresholds in the non-implanted control ear. Threshold differences in the remaining three animals varied from 18 to 69 dB, indicating mild to severe hearing losses. Click- and tone-evoked ABRs measured in a subset of animals before and after implantation revealed a comparable pattern of threshold changes. Thresholds obtained five months or more after implantation--a period in which the prosthesis regularly delivered electrical stimulation to achieve functional activation of the vestibular system--improved in three animals with no or mild initial hearing loss and increased in a fourth with a moderate hearing loss. These results suggest that, although there is a risk of hearing loss with unilateral vestibular implantation to treat balance disorders, the surgery can be performed in a manner that preserves hearing over an extended period of functional stimulation.
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, University of Washington, BB-1165 Health Sciences Building, Box 356515, 1705 NE Pacific Street, Seattle, WA 98195-6515, USA. sbierer@uw.edu
authors.forename: Steven M
authors.initials: SM
authors.lastname: Bierer
authors.forename: Leo
authors.initials: L
authors.lastname: Ling
authors.forename: Kaibao
authors.initials: K
authors.lastname: Nie
authors.forename: Albert F
authors.initials: AF
authors.lastname: Fuchs
authors.forename: Chris R S
authors.initials: CR
authors.lastname: Kaneko
authors.forename: Trey
authors.initials: T
authors.lastname: Oxford
authors.forename: Amy L
authors.initials: AL
authors.lastname: Nowack
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Shepherd
authors.forename: Jay T
authors.initials: JT
authors.lastname: Rubinstein
authors.forename: James O
authors.initials: JO
authors.lastname: Phillips
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold; D019929:Cochlear Implantation / Q000009:adverse effects / Q000295:instrumentation*; D003054:Cochlear Implants; D004558:Electric Stimulation; D004569:Electroencephalography; D016057:Evoked Potentials, Auditory, Brain Stem; D005133:Eye Movements; D034381:Hearing Loss / Q000209:etiology / Q000503:physiopathology; D008253:Macaca mulatta; D008297:Male; D011474:Prosthesis Design; D011930:Reaction Time; D018570:Risk Assessment; D012665:Semicircular Canals / Q000294:innervation*; D013997:Time Factors; D014722:Vestibule, Labyrinth / Q000294:innervation*