Metropolitan Atlanta Developmental Disabilities Study 

The Metropolitan Atlanta Developmental Disabilities Study (MADDS) was the first U.S., population-based epidemiologic study of the prevalence of mental retardation, cerebral palsy, hearing loss, vision impairment, and epilepsy in school-aged children.

The MADDS was conducted as a cooperative agreement between the Division of Public Health, Georgia Department of Human Resources, the former Division of Birth Defects and Developmental Disabilities, National Center for Environmental Health, Centers for Disease Control and Prevention, and the Agency for Toxic Substances and Disease Registry.

 

Purposes

• To develop methods for the surveillance of developmental disabilities.

• To establish prevalence rates of five developmental disabilities: mental retardation, cerebral palsy, vision impairment, hearing loss, and epilepsy.

• To generate hypotheses for further study of risk factors for these five disabilities.

Where

Five counties in metropolitan Atlanta: Clayton, Cobb, DeKalb, Fulton and Gwinnett

Who

Children born in 1975, 1976, 1977; ascertained at age 10 years, in school years 1985-1986, 1986-1987, and 1987-1988

Population statistics for metropolitan Atlanta (1985-1987): Ten-year-old children: Total 89,534

• White: 56,082

• Races other than white: 33,452

Sources of Case Ascertainment

• State of Georgia Department of Education - Nine public school systems

• Department of Human Resources

• Georgia Learning Resources System

• Georgia Psychoeducational Centers

• State Schools

• Private Agencies

• Hospitals/Clinics

• Early Intervention Programs

• CDC-Metropolitan Atlanta Congenital Defects Program

 

Definitions

Developmental Disabilities

• Group of severe chronic conditions, attributable to an impairment in physical, cognitive, speech or language, psychologic, or self-care areas.

• Manifested during developmental period (up to 18-21 years of age).

• Estimated to affect about 10% of school-aged children.
  

Mental Retardation

Intelligence quotient of 70 or less on the most recent psychometric testing performed by a psychometrist (standardized psychological tests)

Cerebral Palsy

Inclusive term that describes a group of nonprogressive disorders occurring in young children in which abnormalities of the brain cause impairment of motor function. The impairment of motor function may result in paresis, involuntary movement, or incoordination. Motor disorders that are transient, disorders that result from progressive diseases of the brain, and motor disorders due to spinal cord abnormalities or injuries are not included.

Hearing Loss

A bilateral, pure-tone hearing loss that averages 40 dB or worse unaided in the better ear at frequencies of 500, 1000, and 2000 Hz (normal speech range).

Vision Impairment

• A measured visual acuity of 20/200 or worse in the better eye with correction, or

• A description of visual acuity that reflects 20/200 or worse (e.g., light perception only), or

• A statement by a trained person (e.g., ophthalmologist, optometrist, etc.) that a child is blind.

Epilepsy

A condition characterized by recurrent (two or more) epileptic seizures, unprovoked by any immediate cause. Multiple seizures occurring in a 24 hour period are considered a single episode. Individuals who have had only febrile seizures or only neonatal seizures are excluded.

National Center on Birth Defects and Developmental Disabilities (NCBDDD) staff have written scientific papers using information from MADDS.  These papers look at such topics as how common autism spectrum disorders are and what causes hearing loss in children.  You can see a list of these papers (starting in 1990) by using the keyword search on the NCBDDD publications Web page.  Choose "MADDS (Metropolitan Atlanta Developmental Disabilities Study)" in the keyword box on the search page.  You can choose whether you want the list to be sorted by author or by date.  You can also choose to have the list appear with or without graphics.  Click on the Submit button.  You will see a list of papers that have information from MADDS.  The list will include the complete reference for each paper and a link to an abstract of the paper or to the full text, when available.  [Go to NCBDDD publications keyword search page]