Adapting a measure of gross motor skills for individuals with CDKL5 deficiency disorder: A psychometric study

Epilepsy Res. 2024 Feb:200:107287. doi: 10.1016/j.eplepsyres.2024.107287. Epub 2024 Jan 15.

Abstract

Purpose: Validated measures capable of demonstrating meaningful interventional change in the CDKL5 deficiency disorder (CDD) are lacking. The study objective was to modify the Rett Syndrome Gross Motor Scale (RSGMS) and evaluate its psychometric properties for individuals with CDD.

Methods: Item and scoring categories of the RSGMS were modified. Caregivers registered with the International CDKL5 Clinical Research Network uploaded motor videos filmed at home to a protected server and completed a feedback questionnaire (n = 70). Rasch (n = 137), known groups (n = 109), and intra- and inter-rater reliability analyses (n = 50) were conducted.

Results: The age of individuals with CDD ranged from 1.5 to 34.1 years. The modified scale, Gross Motor-Complex Disability (GM-CD), comprised 17 items. There were no floor or ceiling effects and inter- and intra-rater reliability were good. Rasch analysis demonstrated that the items encompassed a large range of performance difficulty, although there was some item redundancy and some disordered categories. One item, Prone Head Position, was a poor fit. Caregiver-reported acceptability was positive. Scores differed by age and functional abilities.

Summary: GM-CD appears to be a suitable remotely administered measure and psychometrically sound for individuals with CDD. This study provides the foundation to propose the use of GM-CD in CDD clinical trials. Longitudinal evaluation is planned.

Keywords: CDKL5 deficiency disorder; Developmental epileptic encephalopathy; Gross motor function; Psychometric properties.

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Child, Preschool
  • Epileptic Syndromes*
  • Humans
  • Infant
  • Motor Skills
  • Protein Serine-Threonine Kinases / genetics
  • Psychometrics
  • Reproducibility of Results
  • Rett Syndrome* / diagnosis
  • Rett Syndrome* / genetics
  • Spasms, Infantile*
  • Young Adult

Substances

  • CDKL5 protein, human
  • Protein Serine-Threonine Kinases

Supplementary concepts

  • CDKL5 deficiency disorder