The Role of Visual Attention and Environmental Complexity in Real-world Mobility for People With Lower Limb Amputation

NCT07831707 | Recruiting

• 1 other identifier: HM20030568
• Study Type: observational
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

Despite high medical expenses (\>$500K/patient), mobility improvements achieved during rehabilitation for people with lower limb amputation (LLA) fail to translate into improved real-world outcomes. Even with advances in prosthesis technology enabling faster gait speed, greater walking endurance, and improved mobility confidence, people with LLA report persistent dissatisfaction with real-world mobility, limited ability to walk in the community, and difficulty achieving recommended physical activity levels. Real-world walking requires thinking and moving simultaneously (e.g., cognitive-motor dual-tasking), visually attending to the environment, and navigating varying terrain. In contrast, clinical mobility assessments are usually performed without additional visual or cognitive demands, in controlled environments, and on level surfaces. Current clinical tools used to assess ambulation progression during rehabilitation do not adequately assess these changes in people who have experienced LLA.

Conditions

Lower Limb Amputation

Outcome Measures

Primary Outcomes (16)

• Gait Analysis-Walking Speed

  Measure walking speed meters/second. Captured during dual-task and single-task walking, it is used to measure motor performance. Normal Speed: Healthy adults usually walk at 1.2 to 1.4 meters per second.Fall Risk: A speed below 1.0 meter per second shows a higher risk for falls.Frailty Warning: A speed below 0.6 to 0.8 meters per second suggests a high risk of functional decline or disability.

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Gait Analysis-Stride Length

  Measure the stride length in meters. stride length is the total distance covered during one full cycle of walking or running with the same foot. It measures the space from where one foot touches the ground to when that exact same foot touches the ground again.

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Gait Analysis-Stride length asymmetry

  Assess Stride length asymmetry is an imbalance where the distance covered by the right and left steps differs. Symmetry Index (SI): Compares spatial step metrics or temporal single-limb support times between limbs.Percentage difference: Calculated by contrasting mean left and right step values; values exceeding 10% typically indicate notable dysfunction.

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Cognitive Task Performance Cognitive Task Performance

  Accuracy (percentage correct) of each cognitive task. This reflects cognitive performance and is measured in both dual-task and single-task conditions.

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Cognitive Task Performance

  Measure Response time (milliseconds)

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Functional Mobility (Two-minute Walk Test)

  Two-minute Walk Test measures the total distance a person can walk on a flat, hard surface within two minutes. It evaluates functional mobility, submaximal endurance, and self-paced walking capacity in adults. Recorded to the nearest meter or foot using a measuring wheel, and lap count.

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Functional Mobility (Timed Up and Go)

  Timed Up and Go (TUG) test measures functional mobility, dynamic balance, and fall risk by timing how fast a person stands from a chair, walks 3 meters (10 feet), turns around, walks back, and sits down. Under 10-12 seconds: Normal, independent mobility with low fall risk.12-20 seconds: Moderate risk of falling or subtle mobility issues; requires further evaluation.Over 14-20 seconds: High risk for falls; often indicates difficulty moving outside alone or a need for assistive devices.

  Visit 1

• Eye Tracking (Target Fixation Time)

  Target Fixation Time (seconds; %), The length of time the eye remains relatively still on a target to process detail, reflecting visual attention.

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Eye Tracking (Number of fixations)

  Number of fixations is a core metric measuring how many times a person's eyes pause and focus on a specific area or object. High Fixation Count: indicates frequent attention on an area or element. Low Fixation Count: Means an element was quickly passed over, easily understood, or ignored.

  Visit 1 and visit 2 (which will take place 10-14 days after visit 1)

• Patient Reported Outcomes (Houghton Scale)

  The Houghton Scale assesses a person's confidence and ability in using their prosthesis safely and effectively during everyday mobility tasks. The Houghton Scale is a self-administered, 4-item questionnaire used to assess the functional use of a prosthesis by individuals with lower-limb amputations.It measures how often a patient wears their prosthesis, the types of activities they perform with it, and their perceived stability in various outdoor environments. Total scores range from 0 to 12, with higher scores indicating greater prosthesis use and independence

  Visit 1

• Patient Reported Outcomes (PEQ - Mobility subscale)

  PEQ - Mobility subscale is the The Prosthesis Evaluation Questionnaire - Mobility subscale, captures a person's self reported ability to move and perform daily activities while using their prosthesis. It uses a 5-point ordinal scale (0-4). 0: Not able or hardly able to 4: No problem or almost fully able. The total scale ranges from 0 to 48. A higher score indicates greater mobility.

  Visit 1

• Patient Reported Outcomes (WHODAS)

  WHODAS The World health organization disability assessment schedule 2.0 (WHODAS) evaluates how health conditions impact a person's functioning and participation across major life domains over the past 30 days. Items are rated on a 5-point Likert scale: None (0), Mild (1), Moderate (2), Severe (3), and Extreme or Cannot Do (4). While no universal "cut-off" exists, scores placing a patient in the top 10% of the population distribution-roughly \>10 for the 12-item simple score or \>41 for the 36-item version-likely indicate significant impairment.

  Visit 1

• Patient Reported Outcomes (Activities Specific Balance Confidence Scale)

  Activities Specific Balance Confidence Scale is a self-report instrument used to measure an individual's confidence in maintaining balance while performing 16 various daily activities. Unlike performance-based tests, it captures the patient's perceived ability to avoid falling or becoming unsteady.Patients rate their confidence for each item on a scale from 0% (no confidence) to 100% (complete confidence). The higher the score,the higher the function and physical activity (range \> 80% high function, 50% - 80% moderate function and \< 50% low function.

  Visit 1

• Accelerometry (Daily duration of sitting, standing, stepping)

  Daily duration (minutes) of sitting, standing, and stepping reported as an aggregate mean.

  Between Visit 1 and 2 (which is 10-14 days after visit 1)

• Accelerometry (Daily step count)

  Daily step count will be measured and reported as an aggregate mean.

  Between Visit 1 and 2 (which is 10-14 days after visit 1)

• Accelerometry (Daily walking bouts stepping cadence)

  Daily walking bouts stepping cadence will be reported as an aggregate mean

  Between Visit 1 and 2 (which is 10-14 days after visit 1)

Study Arms (2)

Subjects with Lower Limb Amputation (LLA)

20 participants with below knee amputation.

Other: Comprehensive assessment of walking patterns and functional mobility; Other: Comprehensive assessment of eye movements during walking; Other: Questionnaire Assessments completed

Matched Control

10 sex- and age-matched control participants.

Other: Comprehensive assessment of walking patterns and functional mobility; Other: Comprehensive assessment of eye movements during walking; Other: Questionnaire Assessments completed

Interventions

Comprehensive assessment of walking patterns and functional mobility OTHER

Assessment of accelerometry: Daily duration (minutes) of sitting, standing, stepping, Daily step count, Daily walking bouts stepping cadence, Timed Up and Go and Two-minute Walk Test

Matched Control; Subjects with Lower Limb Amputation (LLA)

Comprehensive assessment of eye movements during walking OTHER

Comprehensive assessment of eye movements during walking including Target Fixation Time (seconds; %) and Number of fixations

Matched Control; Subjects with Lower Limb Amputation (LLA)

Questionnaire Assessments completed OTHER

The following assessments will be completed: World health organization disability assessment schedule 2.0 (WHODAS), and Activities Specific Balance Confidence Scale.

Matched Control; Subjects with Lower Limb Amputation (LLA)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

We will compare gait speed (Aim1) and gaze behavior with eye-tracking glasses (Aim 2) during vision-based (visual puzzles) and non-vision-based (serial subtraction) cognitive-motor dual-tasking while walking on low and high complexity terrain in people with LLA (n=20) and matched controls (n=10).

You may qualify if:

• unilateral transtibial LLA of either dysvascular (diabetes, peripheral vascular disease, and/or infection) or traumatic etiology
• years old minimum
• able to ambulate 2 minutes without rest
• months since LLA
• fitted with terminal prosthesis
• /60 vision or better (with or without glasses/contacts)

You may not qualify if:

• congenital or cancer-related LLA
• ankle-level or above LLA on the contralateral limb
• residual limb wound or contralateral foot ulcer
• unstable heart condition (including unstable angina, uncontrolled cardiac dysrhythmia, acute myocarditis, hypertension, and acute pericarditis)
• acute systemic infection
• prisoner
• inability to follow a 3-step command
• concussion/brain injury in the past 12 months
• active cancer treatment
• preexisting neurological condition (i.e., multiple sclerosis, Parkinson's disease)
• participating in prosthetic rehabilitation
• color-blindness
• history of seizure(s)
• inability to read and communicate in English.
• Participants in the control group must meet the non-amputation-related criteria noted above, be within ±2 years and the same biological sex as their paired participants with LLA.

Sponsors & Collaborators

• Virginia Commonwealth University: lead

Study Sites (1)

Virginia Commonwealth University

Richmond, Virginia, 23239, United States

RECRUITING

Study Officials

• Paul Kline

  Virginia Commonwealth University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Paul Kline

CONTACT

804-828-4483; klinep@vcu.edu

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 14, 2026
• First Posted: September 21, 2026
• Study Start: October 25, 2025
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): May 31, 2027
• Last Updated: September 21, 2026

Record last verified: 2026-09

Locations

US (1)