Self-injurious behavior (SIB) is a devastating condition associated with intellectual and developmental disabilities (IDD). Efforts to understand its development are focused on early childhood when the behavior first emerges. Limited prevalence data on SIB during early childhood are currently available. The purpose of this study was to determine…

Phelan-McDermid syndrome (PMS) is a multiple congenital anomalies and intellectual disabilities syndrome associated with a deletion of chromosome 22 terminal band 13.3. The deletion is associated with severe intellectual disabilities, absent or delayed speech, behavior problems, and autism. The objective of this study was to provide a detailed…

There is a very substantial literature over the past 50 years on the advantages of early detection and intervention on the cognitive, communicative, and social-emotional development of infants and toddlers at risk for developmental delay due to premature birth or social disadvantage. Most of these studies excluded children with severe delays or…

In order to investigate unique and shared characteristics and to determine factors predictive of group classification, quantitative comparisons of behavioral and emotional problems were assessed using the Developmental Behavior Checklist (DBC-P) and the Vineland Adaptive Behavior Scales in autistic disorder, Williams syndrome (WS), and…

Smith-Magenis syndrome (SMS) is a neurobehavioral disorder associated with deletions and mutations of the "RAI1" gene on chromosome 17p11.2. Clinical features of the syndrome include intellectual disability, sleep disturbance, craniofacial differences, and a distinctive profile of stereotypic and self-injurious behaviors. Although the functional…