Abstract
Electrical stimulation involving visual areas of the brain produces artificial light percepts called phosphenes. These visual percepts have been extensively investigated in previous studies involving intracortical microsimulation (ICMS) and serve as the basis for developing a visual prosthesis for the blind. Although advances have been achieved, many challenges still remain with implementing a functional ICMS for visual rehabilitation purposes. Transcranial magnetic stimulation (TMS) over the primary occipital lobe offers an alternative method to produce phosphenes non-invasively. A main challenge facing blind individuals involves navigation. Within the scientific community, methods to evaluate the ability of a visual prosthesis to facilitate in navigation has been neglected. In this study, we investigate the effectiveness of evoking lateralized phosphenes to navigate a computer simulated virtual environment. More importantly, we demonstrate how virtual environments along with the development of a visual prosthesis share a mutual relationship benefiting both patients and researchers. Using two TMS devices, a pair of 40mm figure-of-eight coils were placed over each occipital hemisphere resulting in lateralized phosphene perception. Participants were tasked with making a series of left and right turns using peripheral devices depending on the visual hemifield in which a phosphene is present. If a participant was able to accurately perceive all ten phosphenes, the simulated target is able to advance and fully exit the virtual environment. Our findings demonstrate that participants can interpret lateralized phosphenes while highlighting the integration of computer based virtual environments to evaluate the capability of a visual prosthesis during navigation.
Highlights
One of the main challenges impacting blind individuals involves the ability to navigate independently within their environment [1]
The following study investigates the effectiveness of lateralizing phosphenes using Transcranial magnetic stimulation (TMS) over the occipital lobe with the objective of navigating through a virtual environment
The objective was to evaluate participants ability to successfully exit each virtual environment relying on lateralized phosphene percepts
Summary
One of the main challenges impacting blind individuals involves the ability to navigate independently within their environment [1]. One potential method that could be deployed to tackle these concerns involves the utilization of computer based virtual environments These software can be developed to replicate situations that a blind individual may encounter on a daily basis. Due to its non-invasive utilization, producing phosphenes with TMS instead of ICMS minimizes complications that can arise from surgery [26] Investigating these methods offers a new dimension in terms of developing a visual prosthesis for the blind that could assist them in navigating within their surroundings. We hypothesize that lateralized phosphenes can act as effective artificial sensory inputs to complete a task involving navigation These inputs incorporated within a computer based virtual environment could possibly advance research relevant to the development of a visual prosthesis that can effectively assist a blind individual during navigation
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