Trial Outcomes & Findings for Collision Warning Device for Blind and Visually Impaired (NCT NCT03057496)

NCT ID: NCT03057496

Last Updated: 2021-02-10

Results Overview

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

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 49 participants
• Primary outcome timeframe: During the one-month period of device use
• Results posted on: 2021-02-10

Participant Flow

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.

Participant milestones

Measure	Silent and Active Mode 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.
Overall Study STARTED	49
Overall Study Started Home-use Trial	36
Overall Study COMPLETED	31
Overall Study NOT COMPLETED	18

Reasons for withdrawal

Measure	Silent and Active Mode 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.
Overall Study Withdrawal by Subject	8
Overall Study Lost to Follow-up	5
Overall Study Did not use device during home trial	3
Overall Study Device failure	2

Baseline Characteristics

Collision Warning Device for Blind and Visually Impaired

Baseline characteristics by cohort

Measure	Silent and Active Mode n=31 Participants 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.
Age, Continuous	61 Years n=5 Participants
Sex: Female, Male Female	13 Participants n=5 Participants
Sex: Female, Male Male	18 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	28 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	3 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants
Race (NIH/OMB) Asian	1 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	8 Participants n=5 Participants
Race (NIH/OMB) White	18 Participants n=5 Participants
Race (NIH/OMB) More than one race	1 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	3 Participants n=5 Participants
Region of Enrollment United States	31 participants n=5 Participants
Habitual mobility aid Long cane	28 Participants n=5 Participants
Habitual mobility aid Guide dog	3 Participants n=5 Participants
Cause of vision impairment Retinitis Pigmentosa	8 Participants n=5 Participants
Cause of vision impairment Retinopathy of prematurity	5 Participants n=5 Participants
Cause of vision impairment Other	15 Participants n=5 Participants
Cause of vision impairment Unknown	3 Participants n=5 Participants
Vision impairment onset At birth	17 Participants n=5 Participants
Vision impairment onset Adult	14 Participants n=5 Participants
Duration of vision loss	38 years n=5 Participants
Amount of vision No light perception	11 Participants n=5 Participants
Amount of vision Light perception	8 Participants n=5 Participants
Amount of vision Better than light perception	12 Participants n=5 Participants

PRIMARY outcome

Timeframe: During the one-month period of device use

Population: 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

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

Outcome measures

Measure	Silent Mode n=31 Participants 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.	Active Mode n=31 Participants 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.
Number of Collision Incidents (All Contacts)	13.79 Rate (contacts per 100 hazards per hour) Interval 7.28 to 24.29	9.26 Rate (contacts per 100 hazards per hour) Interval 6.56 to 14.96

SECONDARY outcome

Timeframe: During the one-month period of device use

Population: 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

Collision incidents with body contacts recorded by the device

Outcome measures

Measure	Silent Mode n=31 Participants 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.	Active Mode n=31 Participants 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.
Number of Body Contacts	1.13 Rate (contacts per 100 hazards per hour) Interval 0.45 to 3.08	1.09 Rate (contacts per 100 hazards per hour) Interval 0.3 to 1.97

SECONDARY outcome

Timeframe: 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.

Outcome measures

Measure	Silent Mode n=30 Participants 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.	Active Mode 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.
Device Questionnaire Overall satisfaction	3.68 scores on a scale Standard Deviation 0.74	—
Device Questionnaire Comfort	4.08 scores on a scale Standard Deviation 0.53	—
Device Questionnaire Mobility benefit	3.05 scores on a scale Standard Deviation 1.08	—
Device Questionnaire Ease of operation	3.96 scores on a scale Standard Deviation 0.49	—

Adverse Events

Silent and Active Mode

Serious events: 0 serious events

Other events: 6 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure

Silent and Active Mode n=36 participants at risk 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.

General disorders Minor contact with object in the environment

16.7% 6/36 • Number of events 8 • Adverse event data were collected during the one-month period when subjects were using the device. 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.

Additional Information

Alex Bowers

Schepens Eye Research Institute of Massachusetts Eye and Ear

Phone: 617 912 2512

Email: alex_bowers@meei.harvard.edu

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place