The Phelan-McPosium: A Patient Centered Outcomes Workshop Whitepaper

Cognition is a relatively general term that refers to any mental process. Intellectual disability (ID) refers to a diagnosis given to individuals who demonstrate significant impairments in intellectual and adaptive functioning. Developmental disability (DD), in contrast, is a diagnosis given to individuals who are 5 years old or younger and demonstrate significant delays in at least two areas of functioning (e.g., language, problem solving, or motor skills). Thus, DD is used for younger children who fail to meet expected developmental milestones, whereas ID is typically reserved for children older than 5 years old, as intellectual functioning is less variable and more stable at this age.