Obstacle Negotiation in Older People With and Without Vision Impairment

Low Vision Clinical Trial

Official title:

Impact of Stepping Over Obstacles of Different Contrast and Height on Gait and Eye Movements in Older Adults With and Without Vision Impairment

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT05888441
• Other study ID #: 16447
• Status: Recruiting
• Phase: N/A
• Start date: April 14, 2023
• Est. completion date: December 31, 2025

Study information

• Verified date: August 2023
• Source: Indiana University
• Contact: Kierstyn A Napier-Dovorany, OD
• Phone: 8128554426
• Email: knapier[@]iu.edu
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 200
• Est. completion date: December 31, 2025
• Est. primary completion date: December 31, 2025
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• 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
• Control subjects will have visual acuity of 20/40 or better.

Exclusion Criteria:

• 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)
• Walking or gait abnormalities, such as those caused from an injury, surgery, severe arthritis, or neurological condition such as Parkinson's disease
• Unable to walk without any walking aids such as a walker, cane, guide dog, or oxygen tank.
• Does not speak English

Related Conditions & MeSH terms

• Low Vision
• Vision, Low

Intervention

Other:
• Obstacle characteristics
In 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.

Locations

Country	Name	City	State
United States	Indiana University	Bloomington	Indiana

Sponsors (1)

Lead Sponsor	Collaborator
Indiana University

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Vertical foot clearance, lead limb	Distance from lowest point of foot (heel or toe) to top of obstacle	During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.
Primary	Foot placement variability	Standard deviation of position of toe to obstacle over 2-4 steps before the obstacle	During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.
Primary	Obstacle crossing speed	Speed from lead toe off immediately before the obstacle to trail heel down immediately after the obstacle.	During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.
Primary	Gaze sequencing	Sequence of fixations from start of trial to end of trial, normalized to the total duration and divided into 100 equal segments	During a single intervention visit (Study Visit 2), up to 2-3 hours in duration.