Wearable devices can reduce collision risk in blind and visually
impaired people
New randomized trial shows potential for collision-warning devices as an
added travel safety measure in addition to a conventional long cane

Date:
July 22, 2021
Source:
Massachusetts Eye and Ear Infirmary
Summary:
A new randomized controlled trial shows wearing a vibrating
collision device can reduce collisions in people who are blind
and visually impaired, adding a potential new tool that can be
used by these populations in addition to a long cane, to ensure
independent travel safety.



FULL STORY ==========================================================================
A new study showed that a wearable computer vision device can reduce
collisions for both people who are blind or those who are visually
impaired and using a long cane and/or guide dog by 37 percent, compared
to using other mobility aids alone.


========================================================================== People who have visual impairments are at a significantly higher risk
for collisions and falls. Commonly used mobility aids like long canes and
guide dogs can offer benefits, but come with limitations in effectiveness
and costs, respectively. While some electronic devices are marketed direct-to-consumer claiming to warn wearers of surrounding objects,
there has been little evidence of their effectiveness in actual daily
mobility settings. This is one of the first randomized-controlled trials
to look at the potential benefit of the devices at home and outside of a controlled lab environment. The new study led by vision rehabilitation researchers at Mass Eye and Ear, a member of Mass General Brigham was
published July 22 in JAMA Ophthalmology.

"Independent travel is an essential part of daily life for many people
who are visually impaired, but they face a greater risk of bumping
into obstacles when they walk on their own," said Gang Luo, PhD, an
associate scientist at the Schepens Eye Research Institute of Mass
Eye and Ear, and an associate professor of ophthalmology at Harvard
Medical School. "Although many blind individuals use long canes to detect obstacles, collision risks are not completely eliminated. We sought to
develop and test a device that can augment these everyday mobility aids, further improving their safety." Vibrating wearable device prototype put
to test The experimental device used in the trial was created by Dr. Luo
and colleagues in his vision rehabilitation lab, including the lead author Shrinivas Pundlik, PhD, who designed the computer vision algorithm. The
device and data recording unit were enclosed in a sling backpack with a chest-mounted, wide-angle camera on the strap, and two Bluetooth-connected wristbands worn by the user. The camera is connected to a processing unit
that captures images and analyzes collision risk based on the relative
movement of incoming and surrounding objects in the camera's field of
view. If an imminent collision is detected on the left or right side, the corresponding wristband will vibrate; a head-on collision will cause both wristbands to vibrate. Unlike other devices that simply warn of nearby
objects whether or not a user is moving toward the objects, this device analyzes relative motion, warning only of approaching obstacles that
pose a collision risk, and ignoring objects not on a collision course.

The new study included 31 blind and visually impaired adults who
use either a long cane or guide dog (or both) to aid their daily
mobility. After being trained to use the device, they used it for about a
month at home in conjunction with their typical mobility device (mostly
a long cane). The device was randomized to switch between active mode,
in which the users could receive vibrating alerts for imminent collisions,
and silent mode, in which the device still processed and recorded images,
but did not give users any warning even if potential collisions were
detected. The silent mode is equivalent to the placebo condition in many clinical trials testing drugs. The wearers and researchers would not know
when the device modes changed during the testing and analysis. Collisions
were analyzed by researchers from the recorded videos. The effectiveness
of the device was evaluated by comparing collision incidents that occurred during active and silent modes. The study found that the collision
frequency in active mode was 37 percent less than that in silent mode.



========================================================================== Providing a new option for the visually impaired Long canes are one of
the most effective and affordable mobility tools for a person who is
blind or visually impaired, but they have limitations. Canes primarily
detect hazards on the ground that are within reach; however, hazards
above ground level are often missed. Additionally, the range of long
cane sweeping can be restricted in busy environments, such as cities, in
order avoid hitting nearby pedestrians. Guide dogs are highly effective,
but hard to come by and cost-prohibitive for many, as training a guide
dog typically costs $45,000-$60,000. A chest-mounted, collision-warning
device could provide an option to help people avoid overhanging or moving obstacles that pose challenges to long cane users, Dr. Luo explained.

Alex Bowers, PhD, a clinical researcher and one of the co-authors of the
paper, added that the video recording from the study also provides rich
data about daily life mobility of people with visual impairments. This
can, in turn help researchers better understand the challenges of
collision detection in this population.

"Long canes are still very helpful and cost-effective tools that work
well in many situations, but we hope a wearable device like this can
fill in the gaps that the cane might miss, providing a more affordable,
easier to obtain option than a guide dog," Dr. Bowers said. "The insights provided by our data can be valuable for improving mobility aid training." Next, Dr. Luo and his team seek to leverage ongoing improvements in
mobile processing power and cameras to make the device smaller and more cosmetically appealing. With additional funding, the team hopes that
such a device could be submitted to the U.S. Food and Drug Administration
for approval so that it could be commercially available for people with
low vision.

"Dr. Luo and his team are making great contributions to supporting
and ensuring travel independence in our low-vision community," said
Joan W. Miller, MD, Chief of Ophthalmology at Mass Eye and Ear,
Massachusetts General Hospital, and Brigham and Women's Hospital,
and Chair of Ophthalmology and David Glendenning Cogan Professor of Ophthalmology at Harvard Medical School.

The clinical trial was funded by a U.S. Army Medical Research and Materiel Command grant, and the device is patented by Mass Eye and Ear.

In addition to Drs. Luo, Pundlik and Bowers, co-authors at Mass Eye and
Ear include Vilte Baliutaviciute, BS and Motjaba Moharrer, PhD.

========================================================================== Story Source: Materials provided by
Massachusetts_Eye_and_Ear_Infirmary. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Shrinivas Pundlik, Vilte Baliutaviciute, Mojtaba Moharrer, Alex R.

Bowers, Gang Luo. Home-Use Evaluation of a Wearable Collision
Warning Device for Individuals With Severe Vision Impairments. JAMA
Ophthalmology, 2021; DOI: 10.1001/jamaophthalmol.2021.2624 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210722112958.htm

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