Object localization, discrimination, and grasping with the optic nerve visual prosthesis

Article type: Research Article

Authors: Duret, Florence | Brelén, Måten E. | Lambert, Valerie | Gérard, Benoît | Delbeke, Jean | Veraart, Claude

Affiliations: Neural Rehabilitation Engineering Laboratory, Université catholique de Louvain, Brussels, Belgium

Note: [] Corresponding author: Prof. Claude Veraart, Neural Rehabilitation Engineering Laboratory, Université catholique de Louvain, 54, avenue Hippocrate, box UCL-54.46, B-1200 Brussels. Tel.: +32 2 764 54 40; Fax: +32 2 764 94 22; E-mail: veraart@gren.ucl.ac.be

Abstract: Purpose: This study involved a volunteer completely blind from retinis pigmentosa who had previously been implanted with an optic nerve visual prosthesis. The aim of this two-year study was to train the volunteer to localize a given object in nine different positions, to discriminate the object within a choice of six, and then to grasp it. Methods: In a closed-loop protocol including a head worn video camera, the nerve was stimulated whenever a part of the processed image of the object being scrutinized matched the center of an elicitable phosphene. The accessible visual field included 109 phosphenes in a 14° × 41° area. Results: Results showed that training was required to succeed in the localization and discrimination tasks, but practically no training was required for grasping the object. The volunteer was able to successfully complete all tasks after training. The volunteer systematically performed several left-right and bottom-up scanning movements during the discrimination task. Discrimination strategies included stimulation phases and no-stimulation phases of roughly similar duration. Conclusion: This study provides a step towards the practical use of the optic nerve visual prosthesis in current daily life.

Keywords: Visual prosthesis, blindness, optic nerve, electrical stimulation, object discrimination

Journal: Restorative Neurology and Neuroscience, vol. 24, no. 1, pp. 31-40, 2006