Collision Warning Device for Blind and Visually Impaired

Study Overview
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Brief Summary
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This study evaluates a novel collision warning device to help people with severe vision impairment or blindness avoid collisions with obstacles. The main hypothesis to be tested is that the device reduces the number of collisions with obstacles in everyday activities.

Detailed Description
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Participants with blindness or severe visual field loss (hemianopia or tunnel vision) will be trained to use a collision warning device that alerts them to impending collisions. Participants will use the device at home during everyday mobility for about 1 month. The device is designed to supplement existing mobility devices, such as a long cane or dog guide. The device will provide warnings about potential collisions with mid- or high-level obstacles (which are typically not detected by a long cane).

Official Title
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Wearable Collision Warning Device for Blind and Visually Impaired: Clinical Trial (As Part of: 'Development of a Vision Assistive Device for Veterans With Traumatic Brain Injury-Associated Visual Dysfunctions')

Conditions
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Hemianopia, Hemianopsia, Peripheral Visual Field Defect, Blindness, Retinitis Pigmentosa, Glaucoma

Intervention / Treatment
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* Device: Collision warning device


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Blindness (or very limited vision with visual acuity no better than counting fingers), Or severe peripheral field loss / tunnel vision (≤ 40° remaining visual field) with visual acuity of at least 20/200, Or homonymous hemianopia with visual acuity of at least 20/200; Able to walk independently either with or without mobility aids such as a long cane or guide dog (but without the aid of a sighted guide); Reports at least minor bumps or collisions within the last 3 months; Exclusion Criteria: Currently participating in a mobility training program Diagnosed dementia Significant cognitive decline Participants with hemianopia will be excluded if they have hemianopia for less than 3 months and/or have spatial neglect

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: The device will operate in two modes: active mode (intervention condition), when it gives warnings and, silent mode (control condition), when it does not give warnings. The device will be programmed to generate a different randomized active/silent schedule for each subject. Participants will not know whether it is in the active or silent mode.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention<br>Participants will use the collision warning device as much as possible for about one month during everyday activities, when walking indoors and outdoors. | Device: Collision warning device<br>* The collision warning device is a pocket-sized, electronic system that includes a micro-computer, a clip-on miniature camera, a gyro-sensor, an accelerometer, and a rechargeable battery, all contained within a shoulder bag. It is about the size of a smart phone. When a potential collision is detected by the device it emits a warning to the user, either in the form of an audible beep or a tactile warning through bracelets worn on the wrist. The time to collision will be coded in both the auditory and tactile domains. The device is designed to only give warnings about high risk collisions, so the users will not be continually bombarded by warnings for every potential collision object in the environment.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Collision Incidents (All Contacts) | Collision incidents recorded by the device in everyday use, including long cane contacts and body contacts with surrounding objects in the environment. | During the one-month period of device use | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Body Contacts | Collision incidents with body contacts recorded by the device | During the one-month period of device use | 
| Device Questionnaire | Questionnaire addressing participants' experiences of using the device. Scores were on a 5-point rating scale (1 to 5) with higher scores representing a better score. Questions were grouped into four main categories: i) overall satisfaction, ii) comfort, iii) mobility benefit, and iv) ease of operation. An average score was computed for questions within each category. | During the one-month period of device use |