The Developmentally Disabled Population

The Administration on Developmental Disabilities of the United States Department
of Health and Human Services estimates that there are four million
Americans with developmental disabilities. Data specific to the incidence
and prevalence of developmental disabilities are difficult to obtain
because of the various etiologies present in this population. Conditions
which often fall under the umbrella of developmental disabilities include
mental retardation, autism, epilepsy, spinal cord injury, sensory impairment,
traumatic brain injury, and cerebral palsy.
Though developmental disabilities can be associated with neurological
damage, many of the conditions resulting in a developmental disability do
not result in lowered intellectual functioning. Persons with developmental
disabilities are estimated to comprise 1.7 to 1.8 percent of the population.
This percentage has risen markedly since the mid-1970’s for two reasons: increased
life span for older individuals with disabilities and a greater number
of children and adolescents surviving conditions that previously would have
been fatal. The number of students diagnosed with autism has grown dramatically,
from approximately 5,500 in the 1991-1992 school year to nearly
55,000 in 1998-1999.
Between 200,000 and 500,000 people in the United States over the age of
sixty may have some formof developmental disability. Some of these individuals
present special problems as they age. Those with epilepsy appear to be
at greater risk for osteoporosis, while those with Down syndrome seem to begin
the aging process earlier than others.