Psychometric evaluation of a functional walking test for children with cerebral palsy
The aim of this study was to examine the psychometric properties of the Functional Walking Test (FWT) for a sample of ambulant children with Cerebral Palsy (CP). This included a review of the reliability, validity and sensitivity of the FWT.
CP is a lifelong condition that challenges the individual child and their family. The majority of children with CP will walk either with or without the need for assistive mobility aids. These children will, however, all display some degree of pathological or abnormal gait. As a result, the management of the condition is often directed towards changing or controlling the effect CP has on gait and function.
The use of valid, reliable and sensitive outcome measures in the clinical environment is essential for evaluating the efficacy of interventions and goals. The FWT was designed to specifically describe the functional walking ability of the child with CP. It consists of 11 items, divided into 5 categories: (1) Kneeling (2) From Kneeling (3) Standing (4) Walking (5) Stairs. The maximum score is 23. The FWT was however lacking in psychometric data.
In relation to the reliability of the FWT; the inter-rater reliability was determined through comparison of scores obtained by 8 of raters. The intra-rater reliability was determined through comparison of the raters' scores over two intervals. The raters were given one month to score all 56 participants. One month after the initial scoring, the raters were asked to repeat the scoring.
The validity and sensitivity was assessed through comparison of the performance of the FWT against another measure of established validity, the Gross Motor Function Measure (GMFM), in respect of the same subjects at the same time. The FJVT and GMFM section D and E were administered to all 56 participants by the principal investigator on two occasions over a six month period.
There were 56 children in the study group. The mean age was 9.6 years with a standard deviation of 3.9 years (range 4.2-17.7 years). The subjects were stratified for severity by Gross Motor Function Classification System level (GMFCS), and comprised of 38 GMFCS I, 8 GMFCS II and 10 GMFCS III. Twenty-three participants had CP diplegia (41.2%), twenty two (39.3%) had CP right hemiplegia and 11 (19.5%) had left sided hemiplegia.
The results of the reliability section of the study found that the FWT had high levels of reliability at the levels of individual items and total scoring. Generalisability Correlation that provision of services to those with CP is of the highest standards, and that they are client and family centred at all times.