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Developmental Disabilities

A developmental disability is defined as a severe, chronic disability that is:

• Attributable to a mental or physical impairment or a combination of the two;
• Manifested before the person reaches age 22;
• Likely to continue indefinitely;
• Classified by substantial functional limitations; and
• Classified by a person’s need for special, interdisciplinary or generic care, treatment or other services that are of lifelong or an extended duration.

Disabilities such as brain injury, autism, cerebral palsy and other neurological impairments may be considered developmental disabilities as well. For example, autism is a complex developmental disability that typically appears during the first three years of life. The result of a neurological disorder that affects the functioning of the brain, autism and its associated behaviors have been estimated to occur in as many as 1 in 500 individuals, according to the Centers for Disease Control and Prevention. Children and adults with autism typically have difficulties in verbal and non-verbal communication, social interactions, and leisure or play activities. Persons with autism may exhibit repeated body movements (hand flapping, rocking), unusual responses to people or attachments to objects, and resistance to changes in routines.

Cerebral palsy is a condition caused by damage to the brain, usually occurring before, during or shortly after birth. According to the American Psychiatric Association, between 500,000 and 700,000 Americans have some degree of cerebral palsy. Cerebral palsy is characterized by an inability to fully control motor functions. This may include stiff and difficult movements, involuntary and uncontrolled movements, or a disturbed sense of balance and depth perception. People with cerebral palsy may exhibit spasms, mobility impairments, impairments in sight, hearing or speech, or mental retardation.

As defined by The Arc (formerly the Association for Retarded Citizens of the United States), a person is considered to have mental retardation when there is an intellectual functioning level (IQ) below 70 to 75; significant limitations exist in two or more adaptive skill areas; and the onset of the condition occurs before age 18. There are four levels of mental retardation — mild, moderate, severe and profound. Based on the 1990 U.S. Census, an estimated 6.2 to 7.5 million people have mental retardation. Causes of mental retardation range from genetic disorders to lead poisoning, but The Arc states that the three major causes are Down Syndrome, Fetal Alcohol Syndrome and Fragile-X.

Down Syndrome, the most common cause of mental retardation, is a condition caused by a chromosomal abnormality in which cell development inexplicably results in 47 instead of 46 chromosomes. This extra chromosome affects the orderly development of the brain and body. The Diagnostic and Statistical Manual of Mental Disorders published by the American Psychiatric Association approximates that each year 4,000 children are born with Down Syndrome in the United States. The level of mental retardation for persons with Down Syndrome may range from mild to severe, with the majority functioning in the mild to moderate range.

Fetal Alcohol Syndrome (FAS) is the name given to a group of physical and mental birth defects that are the direct result of a woman’s alcohol consumption during pregnancy. These mental and physical birth defects can include mental retardation, growth deficiencies, central nervous system dysfunction, craniofacial abnormalities and behavioral maladjustments. Not all women who drink alcohol during pregnancy have babies with FAS. Variables affecting outcome include genetics, cigarette smoking and other drug use, nutrition and time of use during pregnancy. According to the Centers for Disease Control and Prevention, the rate of babies born with health problems caused by Fetal Alcohol Syndrome increased six-fold from 1979 to 1993.

In 1991, scientists discovered the gene (called FMR1) that causes Fragile-X. In individuals who have Fragile-X syndrome, a defect in FMR1 shuts the gene down, preventing it from manufacturing the protein that it normally makes. According to the FRAXA Research Foundation, Fragile-X syndrome is the most common inherited cause of mental impairment, affecting approximately 1 in 2,000 males and 1 in 4,000 females worldwide. Symptoms of fragile X syndrome include mental impairment ranging from learning disabilities to mental retardation, attention deficit and hyperactivity, anxiety and unstable mood, autistic-like behaviors, long face, large ears, flat feet and hyperextensible joints.

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