Obstacle Negotiation in Older People With and Without Vision Impairment
ConditionLow Vision
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18+
SponsorIndiana University
About this trial
Falls are common among people with vision impairment and can lead to devastating health consequences. Understanding the functions of vision and how the visual characteristics of obstacles in the walking path impact the gait of people with vision impairment is necessary to create strategies to prevent falls in this population. The purpose of this study is to determine how adults with vision impairment change their gait behavior when stepping over obstacles that vary in height and contrast to the ground. We will then determine the mechanisms of gaze behavior that correlate to the gait behavior.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Age 18 or over
Able to walk independently
Either have normal vision, or impaired vision.
Impaired vision is defined as binocular visual acuity of 20/25 or worse with or without a central scotoma; and/or binocular visual field that is restricted to an average of 100 degrees in diameter or less
Disqualifiers
Not cleared by a medical provider for moderate physical activity
Self-report or have a history of: vestibular disorder or deafness
Medical history of any condition that affects the ability to walk for up to 2 hours with breaks, such as feeling dizzy or faint, chest pain, palpitations, pain or numbness in the legs, shortness of breath,
Cognitive limitations either by self-report or a score on the Mini Mental State Exam below 24 (out of 30)
Trial design
Design model
Parallel
Treatments tested in this trial
Obstacle characteristics
Other interventionIn the walking trials, when an obstacle is present, the obstacle height and obstacle contrast level will be varied across the trial repetitions. Each participant will be exposed to obstacles of two heights: the first will be 1 centimeter in height, and the second will be approximately 20% of the subject's leg length (ranging in physical height between 15 - 22 centimeters to cover a range of leg lengths in the population). Obstacles (of both heights) will also be painted such that their measured luminance (or contrast) level against the floor luminance is varied. High contrast obstacles will have ≥80% Michelson contrast and low contrast obstacles will have ≤30% Michelson contrast.
Treatment groups
200 Participants
are divided into 2 treatment groupsGroup A: Low Vision GroupExperimental treatment 1 intervention
Group B: Control GroupActive comparator 1 intervention
Trial outcomes
Primary outcomes
1
Vertical foot clearance, lead limb
Distance from lowest point of foot (heel or toe) to top of obstacle
Time frame
During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.2
Foot placement variability
Standard deviation of position of toe to obstacle over 2-4 steps before the obstacle
Time frame
During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.3
Obstacle crossing speed
Speed from lead toe off immediately before the obstacle to trail heel down immediately after the obstacle.
Time frame
During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.4
Gaze sequencing
Sequence of fixations from start of trial to end of trial, normalized to the total duration and divided into 100 equal segments
Time frame
During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.Sponsors and contacts
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Source ClinicalTrials.gov