Falls in Older Persons With Limb Loss (FOPLL)

Sensory-Motor Mechanisms Underlying Fall Risk in Transtibial Amputees

Lower limb prosthesis users are known to be at a substantially increased fall risk compared to able-bodied individuals. The interaction between increased fall risk, reduced balance confidence and high prevalence of a fear of falling often leads to restricted mobility and loss of independence. Critically, the cause of these falls and the role that inherent balance plays in fall risk is poorly understood. This study proposes to identify key differences in balance and mobility between older below-knee prosthesis users and able-bodied individuals. By further understanding the differences between these groups and relationships between fall risk and various outcome measures, intervention techniques can be developed to improve functional balance. An improvement in upright balance will reduce the occurrence of falls and fall related injuries in this veteran population, as well as increase their participation in daily activities and improve their quality of life.

Study Overview

• Status: Completed
• Conditions: Amputation; Elderly

Detailed Description

Previous studies have shown that persons with transtibial amputations (TTA) are at a substantially increased risk of falling as compared to able-bodied age-matched controls and have reduced confidence in their balance, both contributing to their restricted mobility and daily activity. This risk increases with progressing age, as aging affects musculoskeletal and somatosensory systems that are vital to controlling upright balance (i.e., maintaining the body center-of-mass (BCoM) within the limits of the base-of-support) and are already compromised in persons with TTA. An important consequence of elevated fall incidence is an increased risk of fall-related injuries that may lead to lost participation and independence. The effects of reduced sensory-motor function on upright balance in older adults has been extensively studied and led to development of effective assessment tools and intervention strategies to minimize fall risk. However, the dearth of similar studies and relatively poor understanding of the effects of additional complications from TTA on upright balance have significantly hampered progress towards addressing this important concern for Veterans with TTA. Consequently, this limits knowledge of predictive factors of falls among these prosthesis users and for informing therapeutic interventions that enhance functional balance. Therefore, the primary objective of this research is to develop an improved understanding of the sensory-motor mechanisms underlying upright balance and fall risk in older Veterans with TTA. The proposed study will compare differences between two age- and gender-matched groups: 1) older unilateral prosthesis users and 2) able-bodied controls.

• Study Type: Observational
• Enrollment (Actual): 23

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60612
      • Jesse Brown VA Medical Center, Chicago, IL

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years to 85 years (Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Older ambulatory individuals with or without unilateral below-knee amputation

Description

Inclusion Criteria:

Inclusion criteria for the recruitment of subjects with below knee amputation include:

• Transtibial amputation
• Daily use of their clinically-prescribed prosthesis for ambulation without an assistive device
• Classified as Medicare Functional Classification Level K2- defined as a patient who "has the ability or potential for ambulation with the ability to traverse low-level environmental barriers such as curbs, stairs, or uneven surfaces - a typical community ambulator"
• Experience walking with a prosthesis for at least one year
• Residuum and amputated side in good condition (e.g., no adherent scars, lesions, ulcers, infections)
• Normal or corrected vision
• Able to walk a 10 m distance and stand quietly for 40 seconds without undue fatigue or health risk

Inclusion criteria for the recruitment of able-bodied controls include:

• Normal or corrected vision
• Able to walk a 10 m distance and stand quietly for 40 seconds without undue fatigue or health risk
• Suffered one or no falls in the previous 12 months

Exclusion Criteria:

Exclusion criteria for all recruited subjects (i.e., limb loss and control) include:

• Musculoskeletal (apart from amputation in the case of amputee subjects) and/or vestibular pathologies that would affect balance and/or stability
• Currently on medication that might affect proprioception and/or balance (e.g., drugs that are ototoxic, such as certain Aminoglycosides and pain killers)
• Cognitive deficits that preclude understanding of the instructions required to conduct the test

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Unilateral Below Knee Amputation; Individuals who walk with a below knee prosthesis
Non-Impaired; Able-bodied controls

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Foot's Height During the Swing Phase of Walking (i.e., Foot Clearance) Measured in Centimeter	Foot clearance of self-selected normal and fast speed walking, calculated as the distance (cm) between the toe and ground as measured with an optical motion capture system.	1 month
Center of Pressure Sway Area During Eyes Open or Closed as Measured Through a Force Plate During Standing and Calculated as Centimeters Squared	Center of pressure sway area during eyes open or closed, calculated as the area (cm*cm) covered by the center of pressure position during standing as measured with a force plate.	1 month
Gait Muscle Activation Effort as Measured by Sensors and Integrating Measured Voltage With Respect to Time as to be Calculated as Millivolts Times Seconds	Integrated Electromyography patterns of leg muscles during self-selected normal and fast speed walking as a proxy measure of muscle effort, calculated from integrating the muscle activity measured by sensors as voltage over time (mv*sec)	1 month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Falls	Number of falls during 12 months prospectively	1 year

Collaborators and Investigators

• Sponsor: VA Office of Research and Development
• Investigators: Principal Investigator: Matthew J. Major, PhD, Jesse Brown VA Medical Center, Chicago, IL

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2017
• Primary Completion (Actual): October 31, 2020
• Study Completion (Actual): October 31, 2020

Study Registration Dates

• First Submitted: September 11, 2018
• First Submitted That Met QC Criteria: September 11, 2018
• First Posted (Actual): September 13, 2018

Study Record Updates

• Last Update Posted (Actual): November 7, 2022
• Last Update Submitted That Met QC Criteria: April 6, 2022
• Last Verified: April 1, 2022

More Information

Terms related to this study

• Keywords: Balance; Gait; Electromyography; Stability; Amputation; Accidental Falls; Artificial Limbs
• Other Study ID Numbers: C1322-W; IK2RX001322 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No