Performance of Real-world Functional Tasks Using an Updated Oral Electronic Vision Device in Persons Blinded by Trauma
SIGNIFICANCE: There is an immediate need for noninvasive therapies to improve the functional abilities of persons blinded by traumatic injury. The BrainPort Vision Pro, an updated hands-free oral electronic vision device, enables perception of visual information using the tongue as a substitute for the eye.
PURPOSE: The purpose of this study was to evaluate the impact of the BrainPort Vision Pro on real-world functional task performance in persons who are profoundly blind (light perception or worse) due to traumatic injury (ocular or cortical).
METHODS: This was a prospective, within-subjects, repeated-measures study. Participants received ten hours of device training and were required to use the device independently for 1 year. Functional performance measures of object identification, orientation and mobility, word identification, and environmental awareness were assessed at baseline, post-device training, and quarterly throughout the year.
RESULTS: Seventeen profoundly blind adults were enrolled in the study. No clinically significant device-related adverse events were reported, demonstrating minimal risks associated with the BrainPort Vision Pro. None of the participants could successfully perform any of the functional tasks at baseline, without the device. After 1 year of independent device use, all participants could identify objects, and 41% identified words beyond chance level while using the device. Forty-one percent of participants could locate a sign, 94% followed a line without veering off, 71% avoided obstacles, 71% walked through a doorway without collision, 100% of participants recognized a door, and 71% identified a window.
CONCLUSIONS: Results demonstrate significant improvements in real-world functional task performance in skill areas important to everyday life. The BrainPort Vision Pro offers a nonsurgical method for improving visual function in persons blinded by trauma. The device can enhance independence and support the successful integration of profoundly blind persons, including veterans and returning service members, into community life.
According to a recent study, approximately 1 million adults are legally blind in the United States,1 with profoundly blind individuals (light perception or worse) accounting for a fraction of this number. Trend assessments predict that owing to population growth and aging this number could dramatically increase by the year 2050. A subset of this growing population includes persons blinded by traumatic events. Traumatic brain injuries and ocular injuries are a growing concern in the military and civilian populations. The visual cortex and pathways connecting the cortical visual centers to the eyes are often impacted by a traumatic brain injury, which can result in vision loss or total blindness.2 Persons who experience blasts and penetrating eye injuries may suffer a similar visual fate, as these types of injuries affect the structure of the eye, leading to severe loss of vision or loss of the eye.
Traumatic eye injuries from blasts and penetrating wounds and traumatic brain injury–related visual disorders are among the most common injury for active military.3 Since the year 2002, more than 375,000 service members have been diagnosed with a traumatic brain injury (Defense Veterans Brain Injury Center, 2018). It has been reported that approximately 75% of patients who experience a traumatic brain injury also have an associated visual impairment.4
Traumatic brain injury is a major cause of mortality and morbidity in the civilian population. Approximately 1.7 million Americans suffer from a traumatic brain injury each year from sports-related injuries, work-related accidents, motor vehicle and bicycle accidents, falls, assaults, stabbings, gunshot wounds, and endoscopic sinus surgery complications.3,5,6 Between the years of 2006 and 2011, there were approximately 5.5 million emergency room visits in the United States owing to traumatic eye injuries.7
Visual impairment and blindness have long-term implications on a person’s health and well-being, mobility, quality of life, and independence.8 There is also a substantial economic impact of visual impairment and blindness related to increased medical care expenses, greater need for care from healthcare professionals and family members, and a reduction in overall health.9 Despite technological advancements and the quest to develop devices to restore lost visual function, current rehabilitation practices and assistive technologies do not sufficiently address the needs of persons blinded by traumatic injury.10
The BrainPort Vision Pro is a nonsurgical, portable oral electronic assistive device for individuals who are profoundly blind. The BrainPort Vision Pro uses the concept of sensory substitution by enabling tactile perception of information normally processed by the visual system. Visual information captured by a digital camera is displayed on the user’s tongue as electrotactile stimulation, which feels like gentle vibrations. Through training, users learn to interpret the stimulation patterns on their tongues to perceive the shape, size, location, and motion of objects and features within an environment and to better perform tasks of orientation and mobility.
The device is not limited by etiology of vision loss and can be used by both congenitally and acquired blind persons, including individuals who do not have a functional optic nerve. Therefore, the BrainPort Vision Pro is a viable option to improve visual function in persons blinded by traumatic injury. The BrainPort Vision Pro is intended to serve as an adjunct to other assistive tools, such as the white cane or dog guide.
Previous evaluations of the first generation of the device, the BrainPort V100, demonstrated safety and effectiveness in the general profoundly blind population; however, it was not tested in persons blinded by trauma.11 The purpose of this current study was to evaluate the impact of the BrainPort Vision Pro on real-world functional task performance in persons who are profoundly blind (light perception or worse) due to traumatic injury.
This study used a prospective, within-subjects, repeated- measures design. The study was conducted at two sites within the United States. Approval was obtained by the New England Institutional Review Board before initiating the study. All study participants provided informed consent to participate after the risks and benefits of the study were explained. This research followed the tenets of the Declaration of Helsinki. This study was registered with ClinicalTrials.gov under the identifier NCT02393118.
Participant Eligibility and Selection
Participants were recruited for the study from August 2015 to February 2016. To be eligible, individuals had to be at least 18 years old and have a medically documented diagnosis of profound blindness due to a traumatic injury, either cortical or ocular. Profound blindness was defined as either bilateral light perception or no light perception in both eyes. It was also required that participants were able to walk independently for 20 ft and had successfully completed orientation and mobility training with a white cane or dog guide. Participants were excluded if they had oral abnormalities, tongue lesions or piercings, allergies to nickel or stainless steel, implanted medical devices, any medical condition that could interfere with study participation, moderate to severe levels of depression (as measured by the Beck Depression Inventory12), or moderate to severe cognitive decline (as measured by the Telephone Interview for Cognitive Status examination13); were current self-reported tobacco users or pregnant; or had hearing loss severe enough that device alerts could not be heard.
Interested candidates were invited to a study site for a screening visit, which included a collection of clinical history and demographic information, an ocular evaluation to document blindness if written documentation was not provided by the participant, and an oral health examination. Participants who met the inclusion criteria, passed the oral health examination, and were willing to participate after receiving brief exposure to the device were enrolled in the study.
BrainPort Vision Pro
The major components of the BrainPort Vision Pro include a headset and electrode array, termed intraoral device (pictured in Fig. 1). The major changes from the initial model (BrainPort V100) include the elimination of the handheld controller and the inclusion of Wi-Fi capability, enabling interaction with external devices. All user controls are now embedded in the headset, offering users full control of device settings and stimulation strength (0 to 100%, 0 to 17 V). The headset provides image processing as well as power functions and includes a camera with zoom functionality. The camera’s field of view ranges from approximately 3 to 47° (horizontal and vertical). The intraoral device measures at 29.5 33.8 7 mm and consists of 394 stainless steel electrodes spaced at 1.32 mm from center to center. A flexible cable permanently tethers the intraoral device to the headset to allow for easy removal or repositioning.
To operate the device, the user uses simple head movements to guide the camera to a scene of interest (Fig. 2). The camera captures the scene as a grayscale digital image and forwards the image for processing. The visual information is then transmitted to the dorsal surface of the tongue via electrotactile stimulation patterns representative of the camera image. In the standard setting, white pixels are felt as strong stimulation, gray pixels as medium-strength stimulation, and no stimulation represents black pixels. Adjustable device settings include zoom, stimulation intensity, an option to invert contrast, edge enhancement, and camera settings to adjust to lighting conditions.
The study protocol included two phases: in-clinic training and independent use.
In-clinic Device Training
In-clinic training consisted of approximately ten hours of BrainPort instruction by an experienced trainer. Trainers used a Web-based viewer (developed by Wicab, Inc; Middleton, WI), which displays the camera image alongside a visual representation of the corresponding intraoral device stimulation patterns (Fig. 3). During training, participants learned device functions and controls and how to interpret the tactile stimulation. Each participant advanced through a standardized training protocol at their own pace. Elements of the training protocol have been previously published.
After training, participants were required to use the device to perform daily activities in their personal environments for a minimum of five hours per month for 1 year. Participants were asked to log activities and the amount of time spent per activity. Each participant was provided with computer-accessible instructions for device cleaning, storage, and safe use. Throughout the year, research staff phoned participants bimonthly to address questions and inquire about any potential adverse events.
Functional performance measures were designed to simulate real-world activities that are difficult or impossible to complete without the use of assistive devices, within a controlled and reproducible environment. These tasks included object recognition, word identification, orientation and mobility, and environmental awareness. Baseline measurements were collected during the initial screening in which participants did not use the BrainPort Vision Pro or any other devices or techniques to complete the tasks.
Functional performance measurements were obtained a second time immediately after device training and quarterly (at 3, 6, 9, and 12 months) throughout the year. Participants were permitted to use the BrainPort Vision Pro only during follow-up assessments.
For the common objects and place setting objects recognition task, four objects were placed side-by-side on a table draped in black cloth both 10 in apart from each other and from the edge of the cloth. Seated 18 in front of the objects, the participant was instructed to use the BrainPort Vision Pro to locate one of the target objects and then reach out and touch it without touching any other object on the table (Fig. 4). The participant was given 2 minutes to identify and touch the target object; otherwise, the trial was marked as incorrect. The participant was asked to repeat the task 10 times with a different target object chosen for each trial. For each quarterly assessment session, the same set of objects was used. The target object and order of objects displayed were randomized. The four common objects used for this task included a softball, coffee mug, spoon, and plastic banana. The four-place setting objects included a fork, bowl, plate, and cup.
Word identification tasks used flash cards and signs. Ten three to five-letter words printed on cardstock flashcards were individually presented to participants who were asked to verbally identify each word presented (previously unknown to participants). To successfully complete the task, participants were to read each word within 3 minutes, repeating the task 10 times. Correctly identifying at least 6 of the 10 words presented represented performance above chance level. For each assessment session, the same set of words was used, and the order of word presentation was randomized. The words were as follows: bed, good, cat, you, box, fish, now, sun, time, and white.
For the sign task, four signs commonly found in public places were simultaneously positioned on the walls of a 15-ft-long hallway at varying heights due to different configurations of hallways across study sites. The distance of the signs from the starting point was specified so that the measurement was consistent across all sites. One randomized pass/fail trial was conducted in which participants were given 10 minutes to locate and navigate toward the target sign using only the BrainPort Vision Pro. Participants were not permitted to use any other assistive device during this task. The trial
was marked as successful if the participant either touched the requested sign on their first attempt or placed their hand within 5 in from the edge of the sign (Fig. 5). The target sign was randomized among the four signs for each assessment. The signs included Men, Women, Danger, and Stairs.
The orientation and mobility tasks included following a line,15 avoiding an obstacle, and navigating through a doorway. A 20-ft- long and 2-in-wide high-contrast line was placed on the floor, and either it was straight from start to finish, it or had a single right or left turn (Fig. 6). Participants were instructed to follow the line, and the trial was determined to be successful if the participant did not veer off the line (or beyond approximately 5 in from the line). For the obstacle avoidance task, an obstacle was placed on the floor over the line in a randomly chosen location. Participants were instructed to locate the obstacle, navigate around it, and return to the line. The obstacle was a lightweight cardboard box that the participants would likely kick out of their path if they did not successfully navigate around it, reducing the risk of injury. Lastly, participants were asked to identify a doorway in the room and navigate through the doorway without colliding with the frame. All orientation and mobility tasks were performed once per quarterly assessment, and performance was scored as pass/fail. For the environmental awareness tasks, participants were asked to identify the location of a doorway and window. Participants were placed in a random location of the room and asked to identify the location of the door and window, either by navigating to it or pointing to it if it was not within reach. Each environmental awareness task was performed once and scored as pass/fail.
Adverse events were documented during bimonthly phone calls and quarterly assessment sessions, which included an oral examination. The primary safety objective was to demonstrate no occurrence of clinically significant device-related adverse events. Success rates were determined for all functional performance measures at each assessment period. Success rates were defined as the ability to successfully perform a task at a statistically greater than chance level.
For the object recognition and the flash card tasks, it was predetermined that correctly identifying more than 6 of 10 objects and words within an assessment period represented successful performance at a rate greater than chance level. A repeated-measures analysis of variance was performed on the object recognition and word identification tasks to determine whether there were statistically significant improvements in these skill areas across the duration of the study.
Twenty-two participants met the eligibility criteria and were enrolled in the study. Five participants withdrew from the study before their final assessment owing to lack of interest or time constraints. The mean age of the 17 participants who completed the study was 42.3 years (range, 21 to 66 years), and the majority of participants lost their vision as a result of a traumatic brain injury. All participants used at least one mobility tool (white cane, dog guide, or mobility devices) on a regular basis, and the majority (70%) of the participants could read braille. This information and additional demographic data for this study sample are provided in Table 1.
No clinically significant device-related serious adverse events occurred throughout the study; therefore, the safety objective was met. Six nonserious device-related adverse events were reported by four participants. These events included one report of tongue tingling, two reports of a headache by the same participant, one participant report of change in taste that lasted two to three hours after device use that occurred at two different points in time, and one report of nausea. All events were considered to be mild in severity, the device use was not modified, and the participants fully recovered before the completion of their study participation.
Independent Device Use
Usage remained consistent throughout the study, and participants reported the use of approximately 15 hours per quarter. Total independent usage reported for the overall study ranged from 30 to 138 hours. Reported usage hours were not related to performance on any of the functional tasks across assessment periods (P’s > .05).
In addition to performing the activities provided by the research staff, the participants who recorded activities in their home log reported accomplishing the following: exploring their neighborhood, detecting that lights were on and off, recognizing objects around the home based on shape and size, reading lower case letters, reading labels on familiar common objects, navigating outdoor environment independently, identifying edges of sidewalk, avoiding ground obstacles, and exploring artwork in a museum.
None of the participants were able to complete any of the functional performance measures beyond chance at baseline testing.
After 1 year of independent use, all participants could identify at least 6 of 10 target common objects and 6 of 10 place setting objects, which represents performance levels above chance. A repeated-measures analysis of variance indicates statistically significant improvement in the number of common objects correctly identified from baseline (mean, 1.4 ± 1.1) to 12-month assessment (mean, 9.1 ± 1.1) (F16,5 = 89.42, P < .001) and the number of place setting objects correctly identified from baseline (mean, 1.3 ± 1.6) to 12-month assessment (mean, 9.4 ± 1.1) (P’s ≤ .05) (F16,5 = 51.97, P < .001). The object recognition success rates (percentage of participants who identified at least 6 of 10 objects) across assessment periods throughout the year are displayed in Fig. 7.
Word Identification Tasks
After 1 year of independent use, 41% of participants were able to read at least 6 of 10 flash card words, representing performance levels above chance. A repeated-measures analysis of variance indicates statistically significant improvement in the number of words correct for the flash card task throughout the year from baseline (mean, 0.0 ± 0.0) to 12-month assessment (mean, 4.4 ± 4.4) (F6,5 = 7.64, P < .001). Forty-one percent of participants were able to successfully navigate to and touch the selected sign. Success rates for the flash card task (percentage of participants who read at least 6 of 10 words) and the sign identification task (percentage of participants who successfully completed the task) across assessment periods throughout the year are displayed in Fig. 8.
Orientation and Mobility
After 1 year of independent device use, 94% of participants could follow a line without veering off, 71% could identify and avoid an obstacle in their pathway, and 71% of participants could walk through a door without colliding with the doorframe. The orientation and mobility success rates from baseline to 1 year are displayed in Fig. 9.
At the 12-month assessment, 100% of participants could recognize a door in the room, and 71% could recognize a window in the room. The environmental awareness success rates from baseline to 1 year are displayed in Fig. 10.
After using the device independently at home for 1 year in their personal environments, participants were asked to report the feature that they were most impressed by and/or found most useful. Responses included adding additional information to everyday experiences, engaging in activities that the participant thought they were no longer able to do as a person who is blind, option to zoom into scenes that are at a distance, receiving additional information that would otherwise be impossible to obtain, finding objects and doorways without assistance, and a feeling of hope and increased confidence while using the device.
Areas of dissatisfaction with the device were primarily related to comfort. Participants reported the device felt uncomfortable on the forehead and that the straps were of poor quality and not sturdy enough (these comfort issues were addressed in an updated hardware design immediately after the study). In addition, one participant noted he did not like walking around with the intraoral device in their mouth. Eighty-two percent of participants reported they would use the device daily or weekly outside the study, whereas 18% reported they would not use the device at all. Participants also offered recommendations for added features, including the ability for the device to provide audio feedback on text, facial recognition, signs, and addresses for navigation purposes, and an option to save camera settings.
The findings from this study demonstrate that the BrainPort Vision Pro is safe and effective in everyday use for profoundly blind persons who have experienced a traumatic injury. No clinically significant device-related adverse events or serious adverse events occurred throughout the study. The device-related events that were reported were not serious, and all participants fully recovered, indicating minimal risks associated with the device. In addition, the events reported were consistent with those reported in a long-term evaluation of the current U.S. Food and Drug Administration–cleared device, the BrainPort V100.11 Therefore, it can be determined that the BrainPort Vision Pro does not pose any additional risks.
The findings from this study are comparable with previous findings on the safety and effectiveness of the BrainPort V100 device in the general blind population.11 At baseline, participants were not able to perform any of the functional performance tasks beyond chance level without the use of the device. Immediately after training, significant improvement in performance was observed, which remained consistent throughout the study. These results reveal that with training and within a short period of time participants are able to perform basic BrainPort Vision Pro tasks in skill areas that are important to performing activities of daily living.
The ability to use the BrainPort Vision Pro to locate an object is a useful skill that eliminated the need to sweep an area with one’s hand and allowed an easier method for recovering objects that have been misplaced. More than half of participants were able to successfully identify common and place setting objects immediately after device training. By the 6-month assessment period, all participants could successfully complete the object recognition tasks beyond chance level, and this performance remained consistent through the end of the study. Participants also reported the ability to recognize objects around the home as a meaningful accomplishment.
Similar to previous BrainPort research,11 reading words, including those found on signs, was the most difficult task to accomplish. To achieve this task, participants must learn to zoom the camera and use smooth head movements to scan and identify each individual letter, skills that are often lost in persons who have been profoundly blind for a number of years. These skills were relearned during initial device training and practiced during device use. It is important to note that the word and sign tasks were impossible
for participants to perform without the BrainPort Vision Pro. By the end of the study, 41% of participants could perform both tasks beyond chance level.
Identifying words and characters with the BrainPort Vision Pro is useful in situations where text-to-speech and braille are not readily available, such as to quickly identify signs in public places. One participant reported an important accomplishment as being able to read labels on familiar household items. Another participant learned the shapes of lowercase letters by practicing at home, a valuable feat to this individual.
Independent travel is an important goal for individuals who are profoundly blind. The BrainPort Vision Pro promoted safe to travel by assisting users to stay on their pathway and to avoid veering off into potentially dangerous situations, such as near traffic or colliding with other people. In addition, 71% of participants avoided floor obstacles, as well as navigated safely through a doorway. Lastly, the ability to identify key features of one’s environment, such as doorways and windows, provided useful information that can be used to reorient oneself and reestablish travel toward the intended destination.
The majority of participants reported a positive experience using the device and would use it daily or weekly outside of the study. The number of hours the device was used at home was not related to performance on functional tasks measured in this study. This is not surprising, as the home use phase of the study gave the participants an opportunity to explore and practice activities of their choice, which may not have been activities directly related to the measured tasks. Although the majority of assessments were performed indoors under controlled lighting conditions, many participants reported using the device outdoors to perform activities. Outdoor activities at home included exploring their neighborhoods and locating objects of importance, such as the mailbox.
Future research will include more outdoor tasks and expanding the use of a current BrainPort Vision Pro feature, edge enhancement. Edge enhancement software enhances the contrast of edges, useful in situations when the lighting conditions are not ideal, such as navigating a hallway in which there is a low contrast between the walls and floors. Future research will also focus on the development of mobile applications that can be paired with BrainPort technology to read street signs, bus signs, crosswalk signals, and other signs important to safe and independent navigation.
This study illustrates that the BrainPort Vision Pro allows users to interact with their environment in novel and useful ways. The device can assist people who are blind to recognize objects, perform orientation and mobility tasks, spot read, and perceive their environments. The BrainPort Vision Pro offers a nonsurgical method for restoring functional abilities of persons blinded by trauma. In addition, the device can support the successful integration of profoundly blind persons, including blind veterans and returning service members, into community life. With access to the BrainPort Vision Pro, persons who experience sudden blindness due to trauma can regain or enhance independence, directly interact with their environments, and regain a sense of autonomy.
Submitted: February 1, 2018
Accepted: June 19, 2018
Funding/Support: Congressionally Directed Medical Research Programs (W81XWH-14-2-0128; to PG).
Conflict of Interest Disclosure: PG and RH have a financial interest in the BrainPort Vision Pro. The sponsor participated in study design, analysis, and interpretation. The authors were responsible for the preparation of this manuscript and the decision to submit this article for publication. Each of the authors had full access to the study data and take full responsibility for their presentation in this article.
Author Contributions and Acknowledgments: Conceptualization: PG, RH, JS, WS; Data Curation: PG; Formal Analysis: PG, WS; Funding Acquisition: PG, RH; Investigation: PG, MM, TA, JS, WS; Methodology: PG, RH, JS, WS; Project Administration: PG, MM, TA, RH, JS, WS; Resources: PG; Software: RH; Supervision: PG, RH, JS, WS; Validation: RH; Visualization: PG, RH; Writing – Original Draft: PG, WS; Writing – Review & Editing: MM, RH, JS, WS.
ClinicalTrials.gov Registry: First Posted: March 19, 2015, Identifier: NCT02393118.
1. Varma R, Vajaranant TS, Burkemper B, et al. Visual Impairment and Blindness in Adults in the United States: Demographic and Geographic Variations from 2015 to 2050. JAMA Ophthalmol 2016;134:802–9.
2. Zihl J. Rehabilitation of Visual Disorders After Brain Injury. East Sussex, UK: Psychology Press; 2010.
3. Cockerham GC, Weichel ED, Orcutt JC, et al. Eye and Visual Function in Traumatic Brain Injury. J Rehabil Res Dev 2009;46:811–8.
4. Brahm KD, Wilgenburg HM, Kirby J, et al. Visual Impairment and Dysfunction in Combat-injured Servicemembers with Traumatic Brain Injury. Optom Vis Sci 2009;86: 817–25.
5. Steinsapir KD, Goldberg RA. Traumatic Optic Neuropathy: An Evolving Understanding. Am J Ophthalmol 2011;151:928–33.
6. Wisse RP, Bijlsma WR, Stilma JS. Ocular Firework Trauma: A Systematic Review on Incidence, Severity, Outcome, and Prevention. Br J Ophthalmol 2010;94: 1586–91.
7. Haring RS, Canner JK, Haider AH, et al. Ocular Injury in the United States: Emergency Department Visits from 2006–2011. Injury 2016;47:104–8.
8. Jacobs JM, Hammerman-Rozenberg R, Maaravi Y, et al. The Impact of Visual Impairment on Health, Function, and Mortality. Aging Clin Exp Res 2005;17: 281–6. Impact of Visual Impairment and Blindness in the United States. Arch Ophthalmol 2007;125:544–50.
10. Das A, Huxlin KR. New Approaches to Visual Rehabilitation for Cortical Blindness: Outcomes and Putative Mechanisms. Neuroscientist 2010;16:374–87.
11. Grant P, Spencer L, Arnoldussen A, et al. The Functional Performance of the BrainPort V100 Device in Persons Who Are Profoundly Blind. J Vis Impair Blind 2016;110:77–88.
12. Beck AT, Steer RA, Brown GK. Beck Depression Inventory—II. San Antonio 1996;78:490–8.
13. Brandt J, Spencer M, Folstein M. The Telephone Interview for Cognitive Status. Cogn Behav Neurol 1988;1:111–8.
14. Nau AC, Pintar C, Arnoldussen A, et al. Acquisition of Visual Perception in Blind Adults Using the BrainPort Artificial Vision Device. Am J Occup Ther 2015;69:1–8.
15. Humayun MS, Dorn JD, Da Cruz L, et al. Interim Results from the International Trial of Second Sight’s Visual Prosthesis. Ophthalmology 2012;119:779–88.
Patricia Grant, PhD,(1)* Meesa Maeng, BS,(1,2) Tiffany Arango, BS,(3) Rich Hogle, MS,(1) Janet Szlyk, PhD,(2) and William Seiple, PhD(4)
1Wicab, Inc., Middleton, Wisconsin
2The Chicago Lighthouse for People Who Are Blind or Visually Impaired, Chicago, Illinois
3Northeastern University, Boston, Massachusetts
4Lighthouse Guild, New York, New York *email@example.com