Validity and reliability of accelerometer data in the assessment of unilateral transtibial amputee gait patterns : a correlational study

Abstract

Aims and Objectives: Gait deviations exist in specific conditions or pathologies. Accelerometer technology in the assessment of pathological gait has seen an increase in use in the past two decades, however such data in unilateral transtibial amputees is lacking both locally and internationally. This study aims at addressing this research gap by testing for reliability and validity of data obtained by a single trunk accelerometer placed at L5. Subsequently the study aims at establishing normative data for the specific population under investigation. Methodology: The study is a within subject correlational (exploratory) design. Subjects were selected by random lot from the local National Amputee Database. Correlation data was synchronised and obtained by comparing data from a single accelerometer (Delsys© Trignio™) versus a 10-camera three-dimensional motion capture (3DMC) system (Vicon© Bonita). iGAIT developed by Yang et al. (2012) was used to extract spatio-temporal, symmetry, and regularity data. Results: Results from this study show that accelerometer data show good inter-rater reliability with a Wilcoxon signed rank test showing no significant difference on accelerometer placement at p = 0.219. Test-retest reliability and intra-rater reliability was also established at p < .001 level of significance. ICC (absolute) Correlation between accelerometer data and 3DMC ranged from very good (0.868) for step length (m) to excellent (0.983) for velocity (m/s). Symmetry and regularity data could discriminate between a high functioning independent and a low functioning (using an assistive device) unilateral transtibial amputee. Conclusions: This study concludes that accelerometer data is a reliable and valid tool in assessing spatio-temporal, symmetry, and regularity data in unilateral transtibial amputees. Data is highly important in clinical practice and may help determine patients’ quality of life and facilitate decisions on therapeutic or prosthetic interventions. This study also acknowledges the limitation that kinematic and kinetic data cannot be obtained from a single trunk accelerometer. Thus, specific joint angles and moments which constitute aother very important aspect in gait analysis cannot be calculated when using such a methodology.