Consensus definition for developmental regression during childhood

This study set out to create a clear, shared definition of developmental regression in children. Having a consistent definition is important because it helps clinicians recognize these changes earlier and more reliably. Early identification can lead to more timely assessment, support, and intervention for children and their families. A standard definition also makes it easier for researchers to compare findings across different studies, which can improve understanding of why developmental regression happens. To reach agreement, the researchers carried out a global consensus study using a Delphi survey to gather and refine expert opinions. In this study, 41 clinicians from different professional backgrounds and areas of expertise took part, ensuring a broad and informed perspective. Across two survey rounds, the experts worked towards agreement on two key aspects: which areas of development can be affected and how long skill loss must last to be considered meaningful. The group reached consensus on a practical working definition. Developmental regression was defined as a loss of one or more previously acquired skills during childhood that lasts for at least four weeks. The definition also specifies that this loss must occur in at least one of six developmental areas: communication (both verbal and nonverbal), motor skills, cognitive abilities, social interaction, or self-help skills such as daily living activities.