A developmental disability is a disability that originates before an individual attains age 18 years, continues, or can be expected to continue, indefinitely, and constitutes a substantial disability for that individual.
This term shall include mental retardation, cerebral palsy, epilepsy, and autism. This term shall also include disabling conditions found to be closely related to mental retardation or to require treatment similar to that required for individuals with mental retardation, but shall not include other handicapping conditions that are solely physical in nature.
A “substantial disability” means the existence of significant functional limitations in three or more of the following areas of major life activity, as determined by a regional center, and as appropriate to the age of the person:
2) Receptive and expressive language
6) Capacity for independent living
7) Economic self-sufficiency
From Lanterman Act, Sec 4512 (a) and Sec 4512 (l)
People with autistic disorder usually have significant language delays, social and communication challenges, and unusual behaviors and interests. Many people with autistic disorder also have intellectual disability. Autistic disorder is present before the age of 3 and lasts throughout a person's life, although symptoms may improve over time.
Cerebral palsy refers to a group of disorders that affect a person’s ability to move and to maintain balance and posture. It is due to a non-progressive brain abnormality, which means that it does not get worse over time, though the exact symptoms can change over a person’s lifetime. People with cerebral palsy have damage to the part of the brain that controls muscle tone. Muscle tone is the amount of resistance to movement in a muscle. It is what lets you keep your body in a certain posture or position.
Epilepsy, sometimes referred to as seizure disorder, is a general term that refers to a tendency to have recurrent seizures. There are many kinds of seizures, but all involve abnormal electrical activity in the brain that causes an involuntary change in body movement of function, sensation, awareness, or behavior.
Symptoms can vary from a momentary disruption of the senses, to short periods of unconsciousness or staring spells, to convulsions.
Epilepsy can be caused by many different conditions that affect a person’s brain. Often no definite cause can be found. Epilepsy cannot be transmitted from person to person.
Mental Retardation (Intellectual Disability)
Intellectual disability is characterized both by a significantly below-average score on a test of mental ability or intelligence and by limitations in the ability to function in areas of daily life, such as communication, self-care, and getting along in social situations and school activities. Intellectual disability is sometimes referred to as cognitive disability or mental retardation.
Children with intellectual disability can and do learn new skills, but they develop more slowly than children with average intelligence and adaptive skills. There are different degrees of intellectual disability, ranging from mild to profound. A person’s level of intellectual disability can be defined by their intelligence quotient (IQ), or by the types and amount of support they need.