Visual Perception for the Blind: The BrainPort Vision Device
By using their tongues, sightless people may be able to “see” again.
Aimee Arnoldussen, PhD • Donald C. Fletcher, MD
Individuals with LP or NLP vision are among the most challenging, and heartbreaking, patients we encounter. Our ability to improve their circumstances is woefully limited. Any efforts that can provide them with some gain in sensory input will improve their independence, and with it, their quality of life.
The BrainPort vision device is an investigational, non-surgical visual prosthetic that translates information from a digit al video camera to the user's tongue, using gentle electrical stimulation. With training, totally blind users learn to interpret the images on their tongue as information about the scene in front of them (Figure 1). The benefits include increased independence, improved safety, mobility, object recognition and the ability to apply the technology toward specific hobbies and recreational situations. Past users have used the device to read words, play games such as tic-tac-toe, build a snowman and recognize the holds while rock climbing.
Figure 1. With training, totally blind users learn to interpret the images on their tongue as information about the scene in front of them.
The BrainPort vision system consists of a postage-stamp–sized array of 400 electrodes placed on the top surface of the tongue (Figure 2), a digital video camera affixed to a pair of sunglasses and a hand-held controller for settings, such as zoom and control of the stimulation level. Visual information is collected from the user-adjustable head-mounted camera (field of view 3º to 73º) and is sent to the BrainPort handheld controller.
Figure 2. The BrainPort vision system consists of a postage-stamp–sized array of 400 electrodes placed on the top surface of the tongue.
The controller translates the visual information into a stimulation pattern that is displayed on the tongue. The tactile image is created by presenting white pixels from the camera as strong stimulation, black pixels as no stimulation and gray pixels as medium levels of stimulation, with the ability to invert contrast when appropriate. Users describe the perception as moving pictures drawn on their tongue with effervescing bubbles.
PATIENT SELECTION CRITERIA
The BrainPort vision device is initially being studied with individuals having no useful vision (light perception or worse), as preliminary clinical studies have confirmed successful use by these individuals. Because the BrainPort vision device requires a training period, initial users are more likely to be younger, technologically savvy and independently mobile users. Unlike other visual prosthetic technologies (retinal and cortical implants), the BrainPort provides benefits for a wide range of blindness etiologies (including both congenitally and acquired) and does not require any surgery.
Training is provided by an orientation and mobility instructor, a low vision professional, or those with similar backgrounds in blindness rehabilitation. Training performance is monitored using an accessory that displays video from the user-mounted camera and provides a visual depiction of the stimulation pattern on the tongue (Figure 3).
Training occurs across a variety of tasks to encourage generalized learning. New users receive at least 10 hours of training prior to independent use. Skills are expected to continue to develop beyond the initial training period.
Figure 3. Training performance is monitored using an accessory that displays video from the user mounted camera (top) and provides a visual depiction of the stimulation pattern on the tongue (bottom).
Wicab Inc., the developer of the technology, has launched a one-year FDA clinical study (October 2011) to evaluate the safety and efficacy of the BrainPort vision device in subjects who are profoundly blind, with only light perception or worse. Participants meeting the study criteria will be given training and access to a BrainPort vision device to use at home. Participants will make quarterly clinic visits to monitor safety and efficacy, which will be evaluated by an object-recognition task, a word-identification task and a mobility task.
Seven sites across the United States and Canada (New York, Pittsburgh, Chicago, Wichita, Pensacola, New Orleans and Toronto) will be enrolling 75 participants. For this and other current or future stud ies, doctors can refer patients to Wicab best via e-mail (firstname.lastname@example.org) or by contacting one of the seven the FDA sites directly. Each FDA site is recruiting local subjects within a two-hour driving radius of the site.
Wicab hopes to have FDA approval and have the BrainPort ready for sale in the United States within two years. They are working on overseas approval also, which would allow sales in the EU in approximately March 2012 and in Canada in mid-2012.
In addition to this FDA study, Wicab has received three years of funding via the Defense Medical Research and Development Program of the Department of Defense in conjunction with University of Pittsburgh Medical Center and Carnegie Mellon University. The enrolled subjects, including veterans blinded in recent conflicts, are steering future device development by participating in clinical assessments and providing feedback following their use of the device both at home and in the clinic. Through iterative feedback from subjects, the development team will implement and test hardware and software device enhancements.
The BrainPort vision device allows users to directly and independently perceive the environment in a novel way. The information enables an empowering sensory experience with which users are able to direct their attention at will and interpret the information themselves. Primary benefits include improved safety, mobility and object recognition. Secondary benefits include applying the technology toward specific hobbies and recreational situations. These benefits may enable greater independence at home and school and in business, greatly improving quality of life. Sparing the patient from a need for surgical implantation, as is common in other visual prosthetics, greatly increases the number of potential patients that can benefit from the device. RP
|Aimee Arnoldussen, PhD, is a neuroscientist at Wicab Inc. Donald C. Fletcher, MD, is director of the Frank Stein and Paul S. May Center for Low Vision Rehabilitation at the California Pacific Medical Center in San Francisco, senior scientist at the Smith-Kettlewell Eye Research Institute in San Francisco, and medical director of the Envision Low Vision Rehabilitation Center in Wichita, KS. Dr. Arnoldussen reports significant financial interest in Wicab as an employee. Dr. Fletcher reports minimal financial interest in Wicab. He can be reached via e-mail at email@example.com.|