Abstract
BACKGROUND Developmental regression in children is a concerning symptom as may be an early indication of a neurodevelopmental or neurodegenerative condition or a developmental epileptic encephalopathy. The heterogeneity of conditions that feature developmental regression, and the absence of a universally accepted definition or approach to measuring regression impedes consistent early recognition. Understanding what definitions and measures are used in studies focused on developmental regression in children is a crucial first step towards developing consistency in health care and research.METHODS A scoping review of definitions and measures used for developmental regression was conducted searching Medline, Embase, Cochrane and Psych Info databases. The Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines were followed.RESULTS Of 17374 potential publications, 164 were included. Four condition groups were identified through thematic analysis. These were grouped as Neurodevelopmental (n = 121); Progressive Neurodegenerative (n = 19); Developmental Epileptic Encephalopathies (n = 5); and Genetic conditions (n = 19). Collectively, most studies (83.5%, n = 137) used an operational definition that specified type of skills lost, but less than half of studies specified age of developmental regression onset (39.6.%, n = 65), or duration of skills loss (43.3%, n = 71). Measures to assess developmental regression were inconsistently used and only 3% (n = 5) of studies used a developmental regression specific tool. Nearly half (42.7%, n = 70) used study specific measures and 22% (n = 36) used the Autism Diagnostic Interview-Revised as a single measure.CONCLUSIONS Developmental regression is inconsistently defined and measured. Given the heterogeneity of conditions that can feature developmental regression, there is need for consideration of a definition that can be broadly applied at the time of regression. A consistent approach will enhance research rigor, collaboration potential and advance timely clinical care.