Reliability and validity of the Lower Limb Function Questionnaire when completed by young adult orthotic and prosthetic device users

Abstract

Purpose The Lower Limb Function Questionnaire (LLFQ) was developed as a self-report assessment of lower-limb functional ability for orthotic and prosthetic (O&P) device users to be suitable for a wide range of conditions, cultures, and ages. The measure aims to address an existing gap in tools for the assessment of functional ability in this population. The purpose of this study is to evaluate LLFQ reliability and validity in a sample of young adult O&P users. Methods Adolescents from a secondary school in Kenya completed the LLFQ twice, 6 d apart, and test-retest reliability was assessed using intra-class correlation coefficients. Validity evaluations involved Timed Up-and-Go, 6-min walk, 6-min obstacle course, and/or spatiotemporal gait assessments. Oxygen consumption was measured during walk tests. Associations between the LLFQ and each measure were evaluated using Pearson correlation coefficients for construct validity. Results LLFQ reliability was acceptable (ICC = 0.79, 95% CIs 0.64-0.89). Construct validity was demonstrated via moderate correlation (r > 0.60) with obstacle course distance, gait velocity, stride length, and stance/single support/double support percent of gait cycle. Conclusions Both LLFQ reliability and validity were acceptable in the sample of youth in Kenya. Further testing is required to determine applicability in other cultural contexts. Implications for Rehabilitation The LLFQ may be clinically useful across a variety of cultures and conditions to provide feedback on the effectiveness of rehabilitative treatment or assistive devices for youth with lower limb impairments. The LLFQ may enable specific strengths and challenges to lower limb function to be identified to enable planning of well-targeted rehabilitation.

Test–retest reliability and construct validity of the Aspects of Wheelchair Mobility Test as a measure of the mobility of wheelchair users

“…The question also included an opportunity to provide an explanatory comment. The question format is described in more detail in the accompanying paper and was like that used in the Lower Limb Function Questionnaire and the Wheelchair Components Questionnaire (Funk et al 2017 ; Rispin et al 2017 ). Although heart rate had been monitored using research-grade heart rate monitors in earlier AWMT 1.0 studies, this was not performed in the updated AWMT 2.0 because heart rate had not consistently differentiated between wheelchair types.…”

Discriminatory validity of the Aspects of Wheelchair Mobility Test as demonstrated by a comparison of four wheelchair types designed for use in low-resource areas

“…This flexibility is necessary in real-world research and is of key importance in studies carried out in low-resource areas. The use of letter grades as anchors for the VAS tends to standardise subject response and provide an understandable value to participants, researchers and manufactures (Funk et al 2016 ; Rispin et al 2017 ). However, the letter grades would need to be modified by whatever grading scale is in use in the culture in which a study is carried out.…”

“…The format of the participant response questions in AWMP was based on that used in the Lower Limb Function Questionnaire. This format was selected because VAS format is very likely to provide data suitable for parametric statistical analysis tools, and because each question includes an opportunity to write a comment providing qualitative explanatory information (Funk et al 2016 ).…”

The client satisfaction with device: a Rasch validation of the Arabic version in patients with upper and lower limb amputation

“…Assistive devices play a significant role in rehabilitation and ensuring an enhanced quality of life for individuals who undergo amputation [2]. In patients who have undergone limb amputation, assessment of patient satisfaction with psychometrically comprehensive measures is an important factor along with other evaluations in clinical decision making [3].…”