title: Charge recovery during concurrent stimulation for a vision prosthesis.
abstract: Parallel or concurrent stimulation in an epiretinal neuroprosthesis is likely necessary in order to deliver sufficient phosphenes for effective vision. Important issues with concurrent stimulation are the effect of current distribution which introduces current leakage or 'cross talk' between adjacent electrodes and charge recovery which determines balanced charge being delivered/recovered at each electrode from the previous phase. In this paper, we present the effect of concurrent stimulation of two hexagonally arranged platinum electrode arrays on charge recovery. Balanced and imbalanced (unequal) currents were delivered to the hexagonal arrays when they were immersed in physiological saline. Both simulation and experimental results revealed that charge was not recovered at individual electrodes, particularly when imbalanced currents were delivered. However, total charge injected to both hexagonal arrays was recovered.
authors.affiliation: Graduate School of Biomedical Engineering, University of New South Wales, Sydney, 2052, Australia.
authors.forename: M Mohd
authors.initials: MM
authors.lastname: Addi
authors.forename: S
authors.initials: S
authors.lastname: Dokos
authors.forename: P J
authors.initials: PJ
authors.lastname: Preston
authors.forename: N
authors.initials: N
authors.lastname: Dommel
authors.forename: Y T
authors.initials: YT
authors.lastname: Wong
authors.forename: N H
authors.initials: NH
authors.lastname: Lovell
mesh_terms: D001187:Artificial Organs; D001698:Biomedical Engineering; D003198:Computer Simulation; D004599:Electric Stimulation Therapy; D004566:Electrodes; D055724:Electrophysiological Phenomena; D006801:Humans; D066298:In Vitro Techniques; D010719:Phosphenes; D010984:Platinum; D012160:Retina / Q000502:physiology*
chemical_list: D010984:Platinum