Consensus definition for developmental regression during childhood

To reach an agreed approach to define developmental regression, to improve understanding of aetiology, prevalence, and timing of investigations, and provide standardized and consistent care.

Developmental regression is a symptom of several developmental, epileptic, genetic, and metabolic conditions (e.g. autism, Rett syndrome, childhood dementias, and Landau-Kleffner syndrome). An expert interdisciplinary clinician panel reviewed the literature for existing definitions and formulated a survey using the Delphi method. Health care clinician perspectives on key elements required for a definition were sought. The survey was completed over two rounds and consensus was defined as a minimum of 70% agreement.

Of the 76 clinicians who completed the first-round survey, 41 completed the second round (54%). Consensus was reached on the following definition. Developmental regression refers to: (1) skill(s) loss experienced during childhood lasting a minimum of 4 weeks, and (2) occurring in at least 1 of 6 developmental domains (verbal communication, nonverbal communication, functional motor skills, cognition, social skills, and self-help skills).

A working definition of developmental regression is proposed. The intention is that this definition will undergo improvements through use and evaluation to increase its utility and uptake in clinical care and research.