Does parent report measure performance? A study of the construct validity of the Functional Mobility Scale

Area of Science:

• Pediatrics
• Rehabilitation Medicine
• Neurology

Background:

• Parental reports are commonly used to assess mobility in children with cerebral palsy (CP).
• The validity of the Functional Mobility Scale (FMS) in reflecting actual mobility performance needs further investigation.

Purpose of the Study:

• To evaluate the accuracy of the Functional Mobility Scale (FMS) in measuring mobility performance in children with cerebral palsy (CP).

Main Methods:

• Eighteen children with spastic CP (GMFCS levels II-IV) underwent direct observation of their mobility.
• Parental FMS ratings were collected via telephone by a physiotherapist.
• Agreement between observed mobility and FMS ratings was analyzed using kappa statistics.

Main Results:

• Substantial agreement was observed between direct observation and FMS ratings.
• Agreement was particularly strong for longer distances: FMS 50m (kappa=0.76) and FMS 500m (kappa=0.74).
• Mobility methods varied significantly across Gross Motor Function Classification System (GMFCS) levels and environments.

Conclusions:

• The Functional Mobility Scale (FMS) demonstrates substantial agreement with direct observation of mobility in children with CP.
• FMS is a valid and reliable tool for assessing mobility performance, especially for longer distances, in children with cerebral palsy.