Intellectual Disability Defined

WHAT IS IT?

Intellectual Disability (formerly known as mental retardation)

• Official definition
  • Characterized by significant limitations both in intellectual functioning (IQ <70-75) and in adaptive behavior, which covers many everyday social and practical skills; originates before age 22 (American Association on Intellectual and Developmental Disabilities [AAIDD])
  • It is no longer defined by IQ alone, rather IQ is only part of the evaluation

CAUSE:

Intellectual disability can have many and varied etiologies, including

• Acquired
  • Examples: Infection or injury
• Genetic
  • Chromosomal
    • Examples:  Down syndrome or microdeletion syndrome
  • Molecular / Single Gene Disorder
    • Example: Fragile X syndrome

KEY POINTS:

Practical Definitions

• Normal Intelligence
  • As an adult, able to reason, solve problems, think abstractly, comprehend complex ideas, and learn from experience
  • IQ >85
• Learning, not intellectual, disability
  • As an adult, able to learn/understand complex information, but may require nontraditional teaching approaches
  • Normal IQ
• Borderline intellectual disability
  • As an adult, able to learn/understand simplified information and probably able to live independently
  • Low normal IQ 75-85
• Mild intellectual disability
  • As an adult, able to participate in most family activities and perform many independent tasks, but likely to need supervision similar to a middle school individual
  • Communication, conversation, and language are more concrete and immature than expected
  • IQ 50-75
• Moderate intellectual disability
  • As an adult, able to participate in most family activities but likely to need supervision similar to a grade school person
  • Marked differences in conceptual skills
  • IQ 35-55
• Severe intellectual disability
  • As an adult, attainment of conceptual skills is limited
  • Skills are similar to a toddler/preschool person (< 5-6 year old) requiring care and supervision accordingly
  • IQ 20-40
• Profound intellectual disability
  • As an adult, very limited understanding of symbolic communication in speech or gesture
  • Skills are similar to an infant/toddler requiring care and supervision accordingly; dependent on others for all aspects of daily physical care, health, and safety
  • IQ < 20 or 25

Learn More – Primary Sources:

American Association on Intellectual Disabilities

Pediatrics: Comprehensive Evaluation of the Child With Intellectual Disability or Global Developmental Delays