Children with developmental central hypotonia have reduced muscle tone secondary to non-progressive damage to the brain or brainstem. Children may have transient delays, mild or global functional impairments, and the lack of a clear understanding of this diagnosis makes evaluating appropriate interventions challenging.

This overview aimed to systematically describe the best available evidence for tools to identify and evaluate children with developmental central hypotonia aged 2 months to 6 years.

A systematic review of systematic reviews or syntheses was conducted with electronic searches in PubMed, Medline, CINAHL, Scopus, Cochrane Database of Systematic Reviews, Google Scholar, and PEDro and supplemented with hand-searching. Methodological quality and risk-of-bias were evaluated, and included reviews and tools were compared and contrasted. Three systematic reviews, an evidence-based clinical assessment algorithm, three measurement protocols, and two additional measurement tools were identified.

For children aged 2 months to 2 years, the Hammersmith Infant Neurological Examination has the strongest measurement properties and contains a subset of items that may be useful for quantifying the severity of hypotonia.

For children aged 2-6 years, a clinical algorithm and individual tools provide guidance. Further research is required to develop and validate all evaluative tools for children with developmental central hypotonia.

Gross Motor Family Report: Refinement and evaluation of psychometric properties

Elton D. D. Magalhães, Peter Rosenbaum, Marilyn Wright, F. Virginia Wright, Lesley Pritchard, Kennea M. A. Ayupe, Ana Carolina de Campos, Rosane S. Morais, Hercules R. Leite, Paula S. C. Chagas

Abstract

Aim
To refine the Gross Motor Family Report (GM-FR) using parents' input and to evaluate its psychometric properties.

Method
In this measurement study, 12 parents of children and adolescents with cerebral palsy (CP), aged 2 to 18 years, classified in all levels of the Gross Motor Function Classification System (GMFCS), were interviewed about their experience completing the GM-FR (content validity). Parents' feedback was used to refine the measure which was then completed by 146 families to evaluate internal consistency, and discriminative and concurrent validity. Forty-six parents completed the GM-FR again, 7 to 30 days later, to evaluate test–retest reliability.

Results
GM-FR scoring, pictures, descriptions, and the total number of items were revised based on parents' feedback. The GM-FR version 2.0 demonstrated high internal consistency (Cronbach's α = 0.99), no floor/ceiling effects, and excellent test–retest reliability (intraclass correlation coefficient = 0.99). GM-FR scores discriminated between GMFCS levels (p less than 0.05) and were strongly negatively correlated with GMFCS level (r = −0.92; p less than 0.001). GM-FR scores correlated positively and strongly with the Gross Motor Function Measure-66 (r = 0.94; p less than 0.001) and the Pediatric Evaluation of Disability Inventory – Computer Adaptive Test mobility domain (r = 0.93; p less than 0.001).

Interpretation
Active participation of families in the GM-FR's development facilitated creation of a family-friendly instrument. This study provides strong evidence of reliability and validity to support GM-FR use in clinical practice and research for assessing gross motor performance of children and adolescents with CP.

https://onlinelibrary.wiley.com/doi/10.1111/dmcn.16042

Professor Gareth Baynam is a globally recognised clinical geneticist, researcher, and advocate for rare diseases. He is the Director of the Rare Care Centre at Perth Children's Hospital and the Head of the Western Australian Register of Developmental Anomalies.

With a career dedicated to improving the diagnosis, management, and care of individuals with rare and genetic conditions, he has been at the forefront of integrating cutting-edge technologies such as genomics, artificial intelligence, and precision medicine into healthcare.

Professor Baynam is also a leader in Indigenous health initiatives, championing equitable access to rare disease diagnostics and treatment. Through his work with organizations such as the Global Commission to End the Diagnostic Odyssey for Children with a Rare Disease and the European Rare Diseases Research Alliance (ERDERA), he continues to drive global collaborations and innovations that aim to transform rare disease care.