Energy Expenditure Index as a measure of efficiency of walking on outdoor uneven surface in individuals with cerebral palsy

Abstract

Purpose: This study aims to validate and report responsiveness of Energy Expenditure Index (EEI) during walking on outdoor uneven surface in individuals with cerebral palsy (CP). Methods: Eighty ambulant children with spastic diplegia (Gross Motor Function Classification System II & III) aged between six and 18 years and 58 age matched typically developing children were recruited for ascertaining reliability and validation of EEI during outdoor walking. Responsiveness of EEI was ascertained using anchor-based approach using Functional Mobility Scale in 29 children with CP who were recruited for surgical intervention. Results: EEI had acceptable test–retest reliability and agreement in both typically developing and children with CP. Friedman’s analysis of variance of 29 children with CP showed a significant difference in EEI (χ 2 = 10.15, p = 0.006), Functional Mobility Scale – 50 m (χ 2 =18.77, p = 0.000) and 500 m (χ 2 = 40.19, p = 0.000) scores at 6 and 12 months when compared with baseline. The minimal clinical important difference of EEI during walking on uneven outdoor surface with a concomitant change in functional mobility scale (500 m) at 6 and 12 months was 0.29 and 0.37 beats/m, respectively. Conclusions: EEI during walking on outdoor uneven surface is a stable, valid and reliable measure of energy efficiency in individuals with CP and is responsive to orthopedic intervention in CP. IMPLICATIONS FOR REHABILITATION Energy Expenditure Index during outdoor walking on uneven surface is a valid, reliable and responsive outcome measure for documenting changes in walking efficiency to post-surgical interventions employed to improve walking in individuals with cerebral palsy. Rehabilitation professionals should document the efficiency during outdoor walking on all the post-operative visits. Energy Expenditure Index during outdoor walking can serve as surveillance tool for deterioration in outdoor walking ability.