Developmental Disabilities Definitions

Autism Spectrum Disorders (ASDs)

Autism spectrum disorders (ASDs) are a group of developmental disabilities caused by a problem with the brain that can cause significant social, communication, and behavioral challenges. ASDs can affect a person's functioning at different levels, from very mildly to severely. Read more about ASDs.

Developmental Delay

According to the Department of Education the term developmental delay means a delay in one or more of the following areas: physical development, cognitive development, communication, social or emotional development, or adaptive (behavioral) development. Delays in development differ from other types of learning disabilities because they may improve with intervention and may eventually disappear. For that reason, being aware of early signs of a problem is important. Learn the signs. Act early.

Emotional Disturbance

According to the Department of Education an emotional disturbance is a condition that shows signs of one or more of the following characteristics over a long period of time

• an inability to learn that cannot be explained by intellectual, sensory, or health factors;
• an inability to build or maintain satisfactory interpersonal relationships with peers and teachers;
• inappropriate types of behavior or feelings under normal circumstances;
• a general pervasive mood of unhappiness or depression; or
• a tendency to develop physical symptoms or fears associated with personal or school problems.

The Individuals with Disabilities Education Act's (IDEA) definition for emotional disturbance includes schizophrenia but does not apply to children who are socially confused, unless they have an identified emotional disturbance. Although emotional disturbance has no known cause, several factors have been suggested and researched including heredity, brain disorder, diet, stress, and family functioning.

Hearing Impairment or Hearing Loss

Hearing loss or impairment can happen when any part of the ear is not working in the usual way, including the outer ear, middle ear, inner ear, hearing (acoustic) nerve, and auditory system. Hearing loss can happen any time during life — from before birth through adulthood. Hearing loss can affect a child's ability to develop communication, language, and social skills, and it can happen from different causes. Learn more about hearing loss.

Intellectual Disabilities (formerly Mental Retardation)

Intellectual disability is a term used when there are limits to a person's ability to learn at an expected level and function in daily life. Someone with an intellectual disability may have problems with communication, self-care, and getting along in social situations and school activities. The causes of most intellectual disabilities are not well understood, but experts estimate that 5% to 20% of cases have something to do with environmental exposures to toxins. Read more about intellectual disabilities.

Speech or Language Impairment

According to the Individuals with Disabilities Education Act (IDEA), speech or language impairment is a communication disorder. Examples include stuttering, impaired articulation, or a language or voice impairment that interferes with a child's educational performance. Some causes of speech and language disorders include hearing loss, neurological disorders, brain injury, intellectual disabilities (mental retardation), drug abuse, physical impairments such as cleft lip or palate, and vocal abuse or misuse. However, the cause is often unknown.

Specific Learning Disability

The Department of Education defines specific learning disability as a disorder in one or more of the basic psychological processes involved in understanding or in using spoken or written language.

This type of disability could lead to being unable to fully listen, think, speak, read, write, spell, or do mathematical calculations. This includes conditions such as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia. This category does not include learning problems that are primarily the result of visual, hearing, or motor disabilities; intellectual disabilities; emotional disturbance; or environmental, cultural, or economic disadvantage.