Developmental Disorders

To find patient care programs and faculty treating developmental disorders at Kennedy Krieger Institute, as well as research investigating this disorder, please see the right-hand column below. Additional helpful information, including definitions, symptoms, Institute press releases, Potential magazine articles, and other resources outside the Institute, have also been provided for readers on this page.

Developmental Disorders Overview:

The term "developmental disorder" or "developmental disability" means a severe, chronic disability of an individual that:

  • is attributable to a mental or physical impairment, or combination of mental and physical impairment
  • is manifested before the individual attains the age of 22
  • is likely to continue indefinitely
  • results in substantial functional limitations in three or more of the following areas of major life activity:
    • self-care
    • receptive and expressive language
    • learning
    • mobility
    • self-direction
    • capacity for independent living
    • economic self-sufficiency
    • reflects the individual's need for a combination and sequence of special, interdisciplinary, or generic services, individualized support or other forms of assistance that are of lifelong or of extended duration and are individually planned and coordinated.

*As defined by the Developmental Disabilities Assistance and Bill of Rights Act of 2000, Public Law 106-402.

Developmental Delay

Developmental delay is defined as failure to meet expected developmental milestones in one or more of the following areas: physical, social, emotional, intellectual, speech and language and/or adaptive development (sometimes called self-help skills, which include dressing, toileting, feeding, etc).

These delays are diagnosed when a child performs approximately 25 to 30 percent below age norms in one or more of these areas (with adjustment for prematurity in affected children). Progress occurs at a slower than expected rate following the anticipated sequence. Various medical and environmental causes exist.

Some examples of physical or mental disorders likely to result in delayed development are:

  • Chromosomal abnormalities
  • Genetic or congenital disorders
  • Severe sensory impairments, including hearing and vision
  • Inborn errors of metabolism
  • Disorders reflecting disturbance of the development of the nervous system
  • Congenital infections
  • Disorders secondary to exposure to toxic substances, including fetal alcohol syndrome.

The verification of delay is obtained through an evaluation process, which includes at least three of the following: informed clinical opinion to include observational assessment, standardized development test(s), developmental inventory, behavioral checklist, adaptive behavior measure and parent interview. Developmental delay can occur temporarily, or it can be long-term and never fully resolve.

Examples, Subsets and Synonyms for Developmental Delay:

  • Language Delay
  • Motor Delay
  • Global Delay

Related Press Releases: