ABILOCO-Kids: a Rasch-built 10-item questionnaire for assessing locomotion ability in children with cerebral palsy.

OBJECTIVE To develop a questionnaire (ABILOCO-Kids) based on the Rasch measurement model that assesses locomotion ability in children with cerebral palsy. DESIGN Prospective study and questionnaire development. SUBJECTS A total of 113 children with cerebral palsy (10 (standard deviation 2.5) years old). METHODS A 41-item questionnaire was developed based on existing scales and on the clinical experience of professionals in the field of rehabilitation. This questionnaire was tested separately on the 113 children with cerebral palsy and their parents. Their responses were analysed using the Rasch model (RUMM-2020) to select items that had an ordered rating scale and that fit a unidimensional model. RESULTS The final ABILOCO-Kids scale consisted of 10 locomotion activities, of which difficulty was rated by the parents. The parents gave a more precise assessment of their children's ability than the children themselves, leading to a wider range of measurement that was well-targeted on the sample population and that had good reliability (r=0.97) and reproducibility (intraclass correlation coefficient=0.96). Item calibration did not vary with age, sex or clinical presentation (hemiplegia, diplegia, quadriplegia). The concurrent validity of the ABILOCO-Kids questionnaire was also shown by its correlation with the Gross Motor Function Classification System. CONCLUSION The ABILOCO-Kids questionnaire has good psychometric qualities for measuring a wide range of locomotion abilities in children with cerebral palsy.