Published: January 26, 2018
A Flexible Wireless System for Preclinical Evaluation of Retinal Prosthesis [PDF]
Patrick C. Thien, Rodney E. Millard, Stephanie B. Epp, David A. X. Nayagam
(Received June 30, 2017; Accepted August 21, 2017)
Keywords: electrical stimulation, wireless monitoring, freely moving animals, retinal prosthesis, preclinical
In this paper, we present a novel stimulation controller and monitoring system for evaluating the safety and efficacy of implantable neuroprosthetic devices in a preclinical setting. It features a programmable controller designed to be worn in a custom backpack by freely moving feline subjects. A custom controller powered two, modified, 22-channel clinical stimulators simultaneously. The controller and stimulators together weighed 140 g and measured 85 × 70 × 35 mm3. Power was supplied from a 3350 mAh lithium-ion battery. A Bluetooth-enabled laptop-PC base station managed up to six systems and allowed the remote adjustment of the stimulation amplitude and automated collection of stimulator telemetry data. The initial application was for the chronic safety testing of a 44-channel retinal prosthesis. Thirteen feline subjects were implanted with a suprachoroidal electrode array, which was then stimulated or monitored continuously for an average of 54.5 d. Batteries were changed twice weekly and electrode impedances were recorded hourly. This allowed broken electrodes and other issues to be quickly identified and addressed. The ability to remotely control the stimulation amplitude minimised the amount of subject handling that was required, likely reducing subject stress. Existing preclinical evaluation systems are either designed for short-term experiments and have many features but limited battery life, or for long-term static stimulation and are long-lived, but with restricted stimulation parameters and channel counts. Here, we have described a system designed to improve the chronic safety testing of electrode arrays. While it was used here with a suprachoroidal retinal implant, it could be readily adapted for other preclinical models requiring continuous, deterministic stimulation over a prolonged period.
Corresponding author: David A.X. Nayagam
Cite this article
Patrick C. Thien, Rodney E. Millard, Stephanie B. Epp, David A. X. Nayagam, A Flexible Wireless System for Preclinical Evaluation of Retinal Prosthesis, Sens. Mater., Vol. 30, No. 2, 2018, p. 269-286.