title: System design and performance of a unilateral horizontal semicircular canal prosthesis.
abstract: We have reported preliminary results regarding a prototype semicircular canal prosthesis and concluded that it can provide rotational cues to the nervous system. This paper presents the system design of the prosthesis, and also reports the prosthesis system performance and effectiveness. The prosthesis delivers electrical pulses to the nerve branch innervating the horizontal semicircular canal on one side via implanted electrodes. To allow us to encode both directions of angular velocity, the baseline stimulation pulse frequency was set at 150 Hz, which is somewhat higher than the average firing rate of afferents innervating the semicircular canals in normal guinea pigs (approximately 60Hz). A sensor measures angular velocity to modulate (increase or decrease) the pulse rate. The prosthetic system was provided to a guinea pig whose horizontal canals were surgically plugged. The animal responded to the baseline stimulation initially and adapted to the baseline stimulation in roughly one day. After this baseline adaptation the animal responded to yaw rotation, showing that the function of the canals was partially restored. The experiments also show that the nervous system adapts to the artificial rotational cue provided via electrical stimulation.
authors.affiliation: Department of Otology and Laryngology, Harvard Medical School and the Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston 02114, USA.
authors.forename: Wangsong
authors.initials: W
authors.lastname: Gong
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Merfeld
mesh_terms: D000818:Animals; D003198:Computer Simulation; D004558:Electric Stimulation; D004566:Electrodes; D004582:Electronics, Medical; D006168:Guinea Pigs; D008904:Miniaturization / Q000295:instrumentation / Q000379:methods; D009039:Motion Perception; D009949:Orientation / Q000502:physiology; D004856:Postural Balance / Q000502:physiology; D019736:Prostheses and Implants; D011474:Prosthesis Design / Q000295:instrumentation / Q000379:methods; D015203:Reproducibility of Results; D012399:Rotation; D012665:Semicircular Canals / Q000502:physiology*; D012680:Sensitivity and Specificity