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Measuring mobility limitations in children with cerebral palsy: Rasch model fit of a mobility questionnaire,
Annet J Dallmeijer1, Vanessa A Scholtes, Jules Becher
1Department of Rehabilitation Medicine, EMGO Institute for Health and Care Research, VU University Medical Centre, Amsterdam, The Netherlands. a.dallmeijer@vumc.nl
Insights
A new 28-item mobility questionnaire (MobQues28) was developed for children with cerebral palsy (CP). This tool offers reliable measurement of mobility limitations in ambulant children aged 4-13 years.
Area of Science:
- Pediatric Rehabilitation
- Movement Science
- Clinical Measurement
Background:
- Cerebral palsy (CP) significantly impacts childhood mobility.
- Accurate assessment of mobility limitations is crucial for effective intervention.
- Existing tools may not fully capture the nuances of mobility in children with CP.
Purpose of the Study:
- To develop a Rasch-based, psychometrically sound mobility questionnaire for children with CP.
- To refine an existing mobility questionnaire into a more precise measurement instrument.
- To create the MobQues28 for assessing mobility limitations in pediatric CP populations.
Main Methods:
- A cross-sectional study involving parents of 323 ambulatory children with CP (GMFCS I-IV, aged 2-13 years).
- Application of the Rasch measurement (partial credit) model to select and refine questionnaire items.
- Analysis focused on item fit, response category function, and measurement invariance across demographic groups.
Main Results:
- A subset of 246 children (aged 4-13 years, excluding non-ambulant and younger children) formed the final analysis sample.
- Twenty-eight items demonstrated good fit to the Rasch model after excluding 19 misfitting items.
- The refined questionnaire (MobQues28) exhibited sound measurement properties.
Conclusions:
- The MobQues28 is a valid and reliable instrument for measuring mobility limitations in ambulant children with CP aged 4-13 years.
- This Rasch-based questionnaire shows potential as a valuable tool for clinical research and practice.
- Further validation in diverse pediatric CP populations is warranted.
Objective:
To develop a Rasch-based version of a mobility questionnaire (MobQues28) for children with cerebral palsy (CP).
Design:
Cross-sectional study.
Setting:
Private physical therapy practices and outpatient departments of hospitals and rehabilitation centers.
Participants:
Parents of 323 ambulatory children with CP (Gross Motor Function Classification System [GMFCS] level I-IV; aged, 2-13y).
Interventions:
Not applicable.
Main Outcome Measure:
The mobility questionnaire measures mobility limitations in children with CP by rating the difficulty of executing 47 mobility activities, as reported by the parents. Items for the Rasch-based version were selected based on fit to the Rasch measurement (partial credit) model and invariance of item characteristics across GMFCS level, age group, or sex.
Results:
Analysis revealed a fitting model when nonambulant and/or 2- and 3-year aged children were excluded (leaving a final sample of n=246) and answering categories were collapsed from 9 to 5. Thirteen items were removed from the questionnaire due to misfit to the model, 5 because of disordered thresholds, and 1 because of invariance across age group. Twenty-eight items out of the original 47 items showed good fit to the model.
Conclusions:
The 28-item version of the mobility questionnaire (MobQues28) provides sound measurement properties for measuring mobility limitations in ambulant children with CP, aged 4 to 13 years, and shows promise as an instrument for research purposes.
