The Interrater Reliability of the Greek Expanded and Revised Gross Motor Function Classification System and the Family Report Questionnaire in Cerebral Palsy

TL;DR

The Greek version of a tool for classifying motor function in cerebral palsy shows strong agreement among professionals and parents, especially for older children.

Contribution

This study is the first to evaluate interrater reliability of the Greek GMFCS-E&R across professionals and parents.

Findings

The Greek GMFCS-E&R shows substantial to excellent interrater reliability across professionals and parents.

Agreement is strongest in older age groups and between professionals.

Parents tend to assign higher GMFCS levels than clinicians.

Abstract

What are the main findings?
•The Greek-language GMFCS-E&R demonstrated substantial to excellent interrater reliability across pediatric neurologists, pediatric physiotherapists, and parents, with agreement strengthening in older age groups and reaching near-perfect levels between professionals.•Most disagreements occurred between adjacent GMFCS levels, particularly IV/V and I/II, with parents more frequently assigning higher (more severe) levels than clinicians.

The Greek-language GMFCS-E&R demonstrated substantial to excellent interrater reliability across pediatric neurologists, pediatric physiotherapists, and parents, with agreement strengthening in older age groups and reaching near-perfect levels between professionals.

Most disagreements occurred between adjacent GMFCS levels, particularly IV/V and I/II, with parents more frequently assigning higher (more severe) levels than clinicians.

What are the implications of the main findings?
•The Greek GMFCS-E&R and GMFCS-FR are reliable tools for standardized classification in Greece, supporting consistent clinical decision-making, family-centered assessment, and alignment with international research standards.•The findings demonstrate that the Greek GMFCS-E&R framework can be readily incorporated into everyday multidisciplinary care, enhancing communication among professionals and supporting coordinated service planning across clinical settings.

The Greek GMFCS-E&R and GMFCS-FR are reliable tools for standardized classification in Greece, supporting consistent clinical decision-making, family-centered assessment, and alignment with international research standards.

The findings demonstrate that the Greek GMFCS-E&R framework can be readily incorporated into everyday multidisciplinary care, enhancing communication among professionals and supporting coordinated service planning across clinical settings.

Background/Objectives: The Gross Motor Function Classification System–Expanded & Revised (GMFCS-E&R) is widely used to describe gross motor performance in children with cerebral palsy (CP). Although Greek-language materials are available, interrater reliability across healthcare professionals and parents has not been examined. This study evaluated the reliability of the Greek GMFCS-E&R among a pediatric neurologist, a pediatric physiotherapist, and parents, with an emphasis on descriptors and illustrations for older children and adolescents. Methods: A cross-sectional study was conducted with 111 children and adolescents with CP aged 2–18 years. Professionals classified each child using the Greek GMFCS-E&R brochure (ages 2–6) or the descriptors and illustrations (ages 6–12 and 12–18). Parents completed the age-appropriate GMFCS Family Report Questionnaire. Agreement among the three raters was assessed using Fleiss’ kappa (κF), and pairwise agreement using weighted Cohen’s kappa (κCw), overall and by age band. Results: Overall interrater reliability was substantial (κF = 0.77). Agreement by GMFCS level ranged from κF = 0.68 (Level V) to κF = 0.85 (Level I). Reliability increased with age, reaching κF = 0.74–0.85 in adolescents. Pairwise agreement was excellent across all rater pairs, with near-perfect concordance between the pediatric neurologist and physiotherapist (κCw = 0.98). In >60% of disagreements, parents assigned higher levels, typically between adjacent categories. Conclusions: The Greek-language GMFCS-E&R demonstrates high interrater reliability among healthcare professionals and parents, with excellent agreement when using descriptors and illustrations for older children and adolescents. The GMFCS-FR effectively incorporates parental perspectives and complements clinical assessment, supporting the use of the Greek GMFCS-E&R in routine clinical practice and research settings.