Developmental Trajectories of Developmental Disorders: Early Diagnosis for an Early Intervention

Early identification of children at risk for Intellectual Disability (ID) is complex, as formal diagnoses are often deferred until school age. However, early signs may emerge during the preschool years. This study aims to examine longitudinal changes in cognitive, adaptive and emotional-behavioral functioning from preschool to school age, to identify early markers predictive of later ID.

Eighty-eight children were assessed at two time points: preschool age (T0) and school age (T1). At T0, children were categorized into three diagnostic groups: Global Developmental Delay (GDD), Mixed Specific Developmental Disorder (MSDD), and Language Disorder (LD). At T1, the same children were re-evaluated and classified into: Intellectual Disability (ID), Language Disorder (LD), and Other Diagnoses (OD). Assessments included clinical observations, cognitive evaluations, and parent-reported questionnaires and interviews. Analyses were performed separately at T0, T1, and longitudinally.

At T0, all groups showed impaired adaptive functioning but differed in cognitive abilities, with the GDD group displaying more pronounced delays. At T1, only the ID group maintained significant deficits in both adaptive and cognitive domains. Regarding emotional-behavioral functioning, children with GDD exhibited more attention problems at T0. At T1, the ID group showed increased internalizing and externalizing symptoms, whereas LD and OD groups did not present significant psychopathological issues. A substantial rise in ID diagnoses was also observed at school age.

Monitoring developmental trajectories from an early age is essential to detect risk markers of ID. Early identification can support timely, targeted interventions for children and their families, improving long-term outcomes.