title: A CMOS Neural Interface for a Multichannel Vestibular Prosthesis.
abstract: We present a high-voltage CMOS neural-interface chip for a multichannel vestibular prosthesis (MVP) that measures head motion and modulates vestibular nerve activity to restore vision- and posture-stabilizing reflexes. This application specific integrated circuit neural interface (ASIC-NI) chip was designed to work with a commercially available microcontroller, which controls the ASIC-NI via a fast parallel interface to deliver biphasic stimulation pulses with 9-bit programmable current amplitude via 16 stimulation channels. The chip was fabricated in the ONSemi C5 0.5 micron, high-voltage CMOS process and can accommodate compliance voltages up to 12 V, stimulating vestibular nerve branches using biphasic current pulses up to 1.45±0.06 mA with durations as short as 10 μs/phase. The ASIC-NI includes a dedicated digital-to-analog converter for each channel, enabling it to perform complex multipolar stimulation. The ASIC-NI replaces discrete components that cover nearly half of the 2nd generation MVP (MVP2) printed circuit board, reducing the MVP system size by 48% and power consumption by 17%. Physiological tests of the ASIC-based MVP system (MVP2A) in a rhesus monkey produced reflexive eye movement responses to prosthetic stimulation similar to those observed when using the MVP2. Sinusoidal modulation of stimulus pulse rate from 68-130 pulses per second at frequencies from 0.1 to 5 Hz elicited appropriately-directed slow phase eye velocities ranging in amplitude from 1.9-16.7 °/s for the MVP2 and 2.0-14.2 °/s for the MVP2A. The eye velocities evoked by MVP2 and MVP2A showed no significant difference ( t-test, p=0.34), suggesting that the MVP2A achieves performance at least as good as the larger MVP2.
authors.forename: Kristin N
authors.initials: KN
authors.lastname: Hageman
authors.forename: Zaven K
authors.initials: ZK
authors.lastname: Kalayjian
authors.forename: Francisco
authors.initials: F
authors.lastname: Tejada
authors.forename: Bryce
authors.initials: B
authors.lastname: Chiang
authors.forename: Mehdi A
authors.initials: MA
authors.lastname: Rahman
authors.forename: Gene Y
authors.initials: GY
authors.lastname: Fridman
authors.forename: Chenkai
authors.initials: C
authors.lastname: Dai
authors.forename: Philippe O
authors.initials: PO
authors.lastname: Pouliquen
authors.forename: Julio
authors.initials: J
authors.lastname: Georgiou
authors.forename: Charles C
authors.initials: CC
authors.lastname: Della Santina
authors.forename: Andreas G
authors.initials: AG
authors.lastname: Andreou
mesh_terms: D000818:Animals; D004558:Electric Stimulation / Q000295:instrumentation; D004867:Equipment Design; D019416:Head Movements; D006801:Humans; D058117:Neural Prostheses; D015837:Vestibular Diseases / Q000628:therapy; D014725:Vestibular Nerve / Q000502:physiology*