The Functional Gait Assessment in Older Adults: Validation Through Rasch Modeling.

Area of Science:

• Gerontology
• Rehabilitation Science
• Biomedical Engineering

Background:

• The Functional Gait Assessment (FGA) was developed to improve upon the Dynamic Gait Index (DGI) by addressing its ceiling effect.
• Modifications included adding three more difficult tasks and removing one easier task from the DGI.
• The impact of these modifications on the FGA's item hierarchy was previously unanalyzed.

Purpose of the Study:

• To determine the task ordering and difficulty continuum of the 10 FGA tasks.
• To assess if the FGA's task spread prevents a ceiling effect across varying functional abilities.
• To identify the psychometric properties and placement of the three newly added tasks within the FGA.

Main Methods:

• A retrospective chart review of Functional Gait Assessment scores was performed.
• Rasch modeling was utilized to analyze data from 179 older adults undergoing physical therapy for balance retraining.

Main Results:

• The FGA task hierarchy generally aligned with clinical expectations, though 'walking on level' was found to be of moderate difficulty.
• No ceiling effect was detected, indicating the FGA can assess a wide range of functional abilities.
• Two of the three added tasks were identified as the most challenging, and performance on the 'gait with narrow base of support' task showed higher variability than predicted.

Conclusions:

• The study sample was limited to community-dwelling, independently ambulant older adults, restricting generalizability to other populations.
• The FGA demonstrates clinical appropriateness and construct validity for assessing walking balance in older adults.
• Potential modifications to FGA administration could enhance efficiency.