The words “impairment,” “disability,” and “handicap,” are often used interchangeably. They have very different meanings, however. The differences in meaning are important for understanding the effects of neurological injury on development.
The most commonly cited definitions are those provided by the World Health Organization (1980) in The International Classification of Impairments, Disabilities, and Handicaps:
Impairment:
Any loss or abnormality of psychological, physiological or anatomical structure or function.
Disability:
Any
restriction or lack (resulting from an impairment) of ability to perform
an activity in the manner or within the range considered normal for a
human being.
Handicap:
A disadvantage for a given individual that limits or prevents the fulfillment of a role that is normalAs traditionally used, impairment refers to a problem with a structure or organ of the body; disability is a functional limitation with regard to a particular activity; and handicap refers to a disadvantage in filling a role in life relative to a peer group.
Examples to illustrate the differences among the terms "impairment," "disability," and "handicap."
1. CP example: David is a 4-yr.-old who has a form of cerebral palsy (CP) called spastic diplegia. David's CP causes his legs to be stiff, tight, and difficult to move. He cannot stand or walk.
Impairment:
The inability to move the legs easily at the joints and inability to bear weight on the feet is an impairment. Without orthotics and surgery to release abnormally contracted muscles, David's level of impairment may increase as imbalanced muscle contraction over a period of time can cause hip dislocation and deformed bone growth. No treatment may be currently available to lessen David's impairment.
Disability:
David's inability to walk is a disability. His level of disability can be improved with physical therapy and special equipment. For example, if he learns to use a walker, with braces, his level of disability will improve considerably.
Handicap:
David's cerebral palsy is handicapping to the extent that it prevents him from fulfilling a normal role at home, in preschool, and in the community. His level of handicap has been only very mild in the early years as he has been well-supported to be able to play with other children, interact normally with family members and participate fully in family and community activities. As he gets older, his handicap will increase where certain sports and physical activities are considered "normal" activities for children of the same age. He has little handicap in his preschool classroom, though he needs some assistance to move about the classroom and from one activity to another outside the classroom. Appropriate services and equipment can reduce the extent to which cerebral palsy prevents David from fulfilling a normal role in the home, school and community as he grows.
2. LD example: Cindy is an 8-year-old who has extreme difficulty with reading (severe dyslexia). She has good vision and hearing and scores well on tests of intelligence. She went to an excellent preschool and several different special reading programs have been tried since early in kindergarten.