Preschool Children With Global Developmental Delay
The later developmental trajectory of young children diagnosed early with global developmental delay was determined. Using a prospective study, preschool children diagnosed with global developmental delay were systematically reassessed during the early school years with standardized developmental and functional outcome measures (Battelle Developmental Inventory and Vineland Adaptive Behavior Scale). Of an original cohort of 99 children assessed and diagnosed at a mean age of 3.4 ± 1.1 years, 48 were reassessed at a mean age of 7.3 ± 0.9 years. Group performance on the Battelle Developmental Inventory overall was 66.4 ± 4.3 (mean 100 ± 15). Between 75% and 100% of the cohort performed at least 1.5 SD below the normative mean on the individual domains of the Battelle Developmental Inventory. Similarly, the group mean on the Vineland Adaptive Behavior Scale overall was 63.5 ± 20.8 (mean 100 ± 15), with between 61% and 76% of the cohort scoring more than 1.5 SD below the mean on each of the domains. Univariate and multivariate analyses on potential predictor variables identified a lack of an underlying etiology as predictive of poorer performance on the Battelle Developmental Inventory fine motor and motor domains and increasing severity of initial delay as predictive of poorer performance on the Vineland Adaptive Behavior Scale communication domain and overall score. Similarly, maternal employment and paternal postsecondary education improved Vineland Adaptive Behavior Scale communication scores, whereas paternal postsecondary education alone predicted better socialization and total scores on the Vineland Adaptive Behavior Scale. Children with early global developmental delay demonstrate persistent and consistently poor performance across all developmental and functional domains. Few variables are apparent at intake to predict later performance.

Developmental disabilities are a common heterogeneous group of related chronic disorders of early onset sharing the essential core feature of a predominant disturbance in the acquisition of cognitive, motor, language, and/or social skills that have a significant and continuing impact on the developmental trajectory of the affected child. Global developmental delay is the most common subtype of childhood developmental disability. It can be operationally defined as a significant delay in two or more domains (gross/fine motor, cognitive, speech/language, personal/social, or activities of daily living). Significant is taken to refer to scores 1.5 to 2.0 SD below the mean on norm-referenced age-appropriate developmental tests.

Recent efforts in research in developmental delay have highlighted the delineation of populations of children at risk of developmental delay, the early identification of such children, the possible benefits of early intervention in populations with established risk, and the etiologic yield of a diagnostic evaluation. Surprisingly, few studies have focused on the outcomes or natural history of children diagnosed early in life with developmental delay. Outcome studies have traditionally focused on narrowly defined populations of biologically at-risk children (eg, neonatal intensive care unit survivors) or children with an established risk (eg, Down syndrome, cerebral palsy) rather than the more prevalent community-derived cohort of children referred for developmental delay. Thus, relatively little is known regarding the nosologic stability, temporal evolution, and predictive validity of the global developmental delay diagnostic construct.

The primary objective of this study was to determine the developmental and functional outcomes at school entry (age 7 years) of young children (ie, less than 5 years of age at initial diagnosis) with global developmental delay. Efforts were also undertaken as a secondary objective to identify possible predictor variables at initial intake of eventual outcomes.