Collision Warning Device for Blind and Visually Impaired

• Sponsor: Massachusetts Eye and Ear Infirmary (Other)
• Overall Status: Completed
• CT.gov ID: NCT03057496
• Collaborator: (none)
• Enrollment: 49
• Location: 1
• Arm: 1
• Actual Duration (Months): 22.4
• Patients Per Site Per Month: 2.2

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Hemianopia; Hemianopsia; Peripheral Visual Field Defect; Blindness; Retinitis Pigmentosa; Glaucoma	Device: Collision warning device	N/A

Detailed Description

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).

Study Design

• Study Type: Interventional
• Actual Enrollment: 49 participants
• Allocation: N/A
• Intervention Model: Single Group Assignment
• Intervention 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.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)
• Masking Description: Although this is a single-arm study, participants will be masked in the sense that they will not know whether the device is operating in the active mode (intervention condition), when it gives warnings, or the 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. The investigator conducting the statistical analyses will also be masked as to whether the device was in the active or silent mode
• Primary Purpose: Other
• Official Title: 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')
• Actual Study Start Date: Jan 22, 2018
• Actual Primary Completion Date: Nov 8, 2019
• Actual Study Completion Date: Dec 5, 2019

Arms and Interventions

Arm

Intervention/Treatment

Experimental: Intervention 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; 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.

Outcome Measures

Primary Outcome Measures

1. Number of Collision Incidents (All Contacts) [During the one-month period of device use]

   Collision incidents recorded by the device in everyday use, including long cane contacts and body contacts with surrounding objects in the environment.

Secondary Outcome Measures

1. Number of Body Contacts [During the one-month period of device use]

   Collision incidents with body contacts recorded by the device

2. Device Questionnaire [During the one-month period of device use]

   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.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Schepens Eye Research Institute	Boston	Massachusetts	United States	02114

Sponsors and Collaborators

• Massachusetts Eye and Ear Infirmary

Investigators

• Principal Investigator: Alex Bowers, PhD, Schepens Eye Research Institute, Mass Eye and Ear
• Principal Investigator: Gang Luo, PhD, Schepens Eye Research Institute, Mass Eye and Ear

Study Documents (Full-Text)

• Informed Consent Form - Jan 26, 2019
• Study Protocol and Statistical Analysis Plan - Jan 12, 2021

More Information

Publications

• Pundlik S, Baliutaviciute V, Moharrer M, Bowers AR, Luo G. Data Acquisition, Processing, and Reduction for Home-Use Trial of a Wearable Video Camera-Based Mobility Aid. Transl Vis Sci Technol. 2020 Jun 11;9(7):14. doi: 10.1167/tvst.9.7.14. eCollection 2020 Jun.

• Responsible Party: Alexandra Bowers, Associate Professor of Ophthalmology, Massachusetts Eye and Ear Infirmary
• ClinicalTrials.gov Identifier: NCT03057496
• Other Study ID Numbers: 1007377
• First Posted: Feb 20, 2017
• Last Update Posted: Feb 10, 2021
• Last Verified: Jan 1, 2021

• Individual Participant Data (IPD) Sharing Statement: No
• Plan to Share IPD: No
• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: Yes
• Product Manufactured in and Exported from the U.S.: No
• Additional relevant MeSH terms: Blindness; Hemianopsia; Retinitis; Retinitis Pigmentosa

Study Results

Participant Flow

Recruitment Details	Subjects were recruited between January 2018 and May 2019 via referrals from the Carroll Center for the Blind, the Massachusetts Commission for the Blind and practitioners at vision rehabilitation clinics in the Greater Boston area, and via a pool of volunteers who had previously participated in studies in our lab.

Arm/Group Title	Silent and Active Mode
Arm/Group Description	During the period of home-use of the device, all participants experienced both the silent and active modes on a random schedule. Thus participant flow was the same for silent and active modes and is described for all participants together.
Period Title: Overall Study
STARTED	49
Started Home-use Trial	36
COMPLETED	31
NOT COMPLETED	18

Baseline Characteristics

Arm/Group Title	Silent and Active Mode
Arm/Group Description	During the period of home-use of the device, all participants experienced both the silent and active modes on a random schedule. Thus the baseline measures are the same for active and silent modes (as it was the same participants for both modes) and are reported together.
Overall Participants	31
Age (Years) [Median (Full Range) ]
Median (Full Range) [Years]	61
Sex: Female, Male (Count of Participants)
Female	13 41.9%
Male	18 58.1%
Ethnicity (NIH/OMB) (Count of Participants)
Hispanic or Latino	0 0%
Not Hispanic or Latino	28 90.3%
Unknown or Not Reported	3 9.7%
Race (NIH/OMB) (Count of Participants)
American Indian or Alaska Native	0 0%
Asian	1 3.2%
Native Hawaiian or Other Pacific Islander	0 0%
Black or African American	8 25.8%
White	18 58.1%
More than one race	1 3.2%
Unknown or Not Reported	3 9.7%
Region of Enrollment (participants) [Number]
United States	31 100%
Habitual mobility aid (Count of Participants)
Long cane	28 90.3%
Guide dog	3 9.7%
Cause of vision impairment (Count of Participants)
Retinitis Pigmentosa	8 25.8%
Retinopathy of prematurity	5 16.1%
Other	15 48.4%
Unknown	3 9.7%
Vision impairment onset (Count of Participants)
At birth	17 54.8%
Adult	14 45.2%
Duration of vision loss (years) [Median (Full Range) ]
Median (Full Range) [years]	38
Amount of vision (Count of Participants)
No light perception	11 35.5%
Light perception	8 25.8%
Better than light perception	12 38.7%

Outcome Measures

1. Primary Outcome

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

Outcome Measure Data

Analysis Population Description

The device switched between active and silent modes on a random schedule so data about collision incidents were available for each subject for both conditions

Arm/Group Title	Silent Mode	Active Mode
Arm/Group Description	Participants used the collision warning device as much as possible for about one month during everyday activities, when walking indoors and outdoors. The device switched between silent and active mode on a random schedule. In the silent mode the device detected potential collisions but did not provide any active warnings to the users.	Participants used the collision warning device as much as possible for about one month during everyday activities, when walking indoors and outdoors. The device switched between silent and active mode on a random schedule. In the active mode the device detected potential collisions and gave active warnings to the users via vibro-tactile wristbands.
Measure Participants	31	31
Median (Inter-Quartile Range) [Rate (contacts per 100 hazards per hour)]	13.79	9.26

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Silent Mode, Active Mode
	Comments	A within-subject comparison was performed. Each subject included in the analysis used the device in both the active and the silent mode. Comparison was between the two device operating modes. The null hypothesis was that there was no difference in the rate of contacts between active and silent modes.
	Type of Statistical Test	Superiority
	Comments
Statistical Test of Hypothesis	p-Value	< 0.001
	Comments	Since the outcome (contacts) represented over-dispersed count data and there were repeated measurements per subject, a generalized mixed effects model with a negative binomial family was used with each subject treated as a random intercept.
	Method	Mixed Models Analysis
	Comments	Fixed factors were included in the model to account for factors other than device operating mode that might affect collision rates.
Method of Estimation	Estimation Parameter	Rate ratio
	Estimated Value	0.627
	Confidence Interval	(2-Sided) 95%; 0.536 to 0.734
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.08
	Estimation Comments	Silent mode is the denominator for the rate ratio.

2. Secondary Outcome

Title	Number of Body Contacts
Description	Collision incidents with body contacts recorded by the device
Time Frame	During the one-month period of device use

Outcome Measure Data

Analysis Population Description

The device switched between active and silent modes on a random schedule so data about collision incidents were available for each subject for both conditions

Arm/Group Title	Silent Mode	Active Mode
Arm/Group Description	Participants used the collision warning device as much as possible for about one month during everyday activities, when walking indoors and outdoors. The device switched between silent and active mode on a random schedule. In the silent mode the device detected potential collisions but did not provide any active warnings to the users.	Participants used the collision warning device as much as possible for about one month during everyday activities, when walking indoors and outdoors. The device switched between silent and active mode on a random schedule. In the active mode the device detected potential collisions and gave active warnings to the users via vibro-tactile wristbands.
Measure Participants	31	31
Median (Inter-Quartile Range) [Rate (contacts per 100 hazards per hour)]	1.13	1.09

3. Secondary Outcome

Title	Device Questionnaire
Description	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.
Time Frame	During the one-month period of device use

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Silent and Active Mode
Arm/Group Description	Since participants did not know when the device was in either the silent or the active mode, it was not possible for them to answer questions specific to each mode. The questionnaire was completed after using the device for one month and therefore represents ratings of the device for the whole duration of the trial including both active and silent operating modes.
Measure Participants	30
Overall satisfaction	3.68 (0.74)
Comfort	4.08 (0.53)
Mobility benefit	3.05 (1.08)
Ease of operation	3.96 (0.49)

Adverse Events

Time Frame	Adverse event data were collected during the one-month period when subjects were using the device.
Adverse Event Reporting Description	A brief questionnaire was administered to each subject by telephone each week during the one-month period of device use to check on how much they were using the device and whether they had encountered any difficulties. One question specifically asked whether the subject had experienced any adverse events.
Arm/Group Title	Silent and Active Mode
Arm/Group Description	During the period of home-use of the device, all participants experienced both the silent and active modes on a random schedule. Neither the subject nor the researcher recording adverse events knew whether the device was in silent or active mode at the time when an event occurred, thus the adverse events are reported for all participants and both modes together.
All Cause Mortality
	Silent and Active Mode
	Affected / at Risk (%)	# Events
Total	0/36 (0%)
Serious Adverse Events
	Silent and Active Mode
	Affected / at Risk (%)	# Events
Total	0/36 (0%)
Other (Not Including Serious) Adverse Events
	Silent and Active Mode
	Affected / at Risk (%)	# Events
Total	6/36 (16.7%)
General disorders
Minor contact with object in the environment	6/36 (16.7%)	8

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.