Developmental coordination di... Health Article

Definition

Developmental coordination disorder is diagnosed when children do not develop normal motor coordination (coordination of movements involving the voluntary muscles).

Description

Developmental coordination disorder has been known by many other names, some of which are still used today. It has been called clumsy child syndrome, clumsiness, developmental disorder of motor function, and congenital maladroitness. Developmental coordination disorder is usually first recognized when a child fails to reach such normal developmental milestones as walking or beginning to dress him- or herself.

Children with developmental coordination disorder often have difficulty performing tasks that involve both large and small muscles, including forming letters when they write, throwing or catching balls, and buttoning buttons. Children who have developmental coordination disorder have often developed normally in all other ways. The disorder can, however, lead to social or academic problems for children. Because of their underdeveloped coordination, they may choose not to participate in activities on the playground. This avoidance can lead to conflicts with or rejection by their peers. Also, children who have problems forming letters when they write by hand, or drawing pictures, may become discouraged and give up academic or artistic pursuits even though they have normal intelligence.

Causes and symptoms

The symptoms of developmental coordination disorder vary greatly from child to child. The general characteristic is that the child has abnormal development of one or more types of motor skills when the child's age and intelligence quotient (IQ) are taken into account. In some children these coordination deficiencies manifest as an inability to tie shoes or catch a ball, while in other children they appear as an inability to draw objects or properly form printed letters.

Some investigators believe that there are different subtypes of developmental coordination disorder. While there is disagreement over how to define these different subtypes, they can provide a useful framework for the categorization of symptoms. There are six general groups of symptoms. These include:

• general unsteadiness and slight shaking
• an at-rest muscle tone that is below normal
• muscle tone that is consistently above normal
• inability to move smoothly because of problems putting together the subunits of the whole movement
• inability to produce written symbols
• visual perception problems related to development of the eye muscles

Children can have one or more of these types of motor difficulties.

Developmental coordination disorder usually becomes apparent when children fail to meet normal developmental milestones. Some children with developmental coordination disorder do not learn large motor skills such as walking, running, and climbing until a much later point in time than their peers. Others have problems with such small muscle skills as learning to fasten buttons, close or open zippers, or tie shoes. Some children have problems learning how to handle silverware properly. In others, the disorder does not appear until they are expected to learn how to write in school. Some children just look clumsy and often walk into objects or drop things.

There are no known causes of developmental coordination disorder. There are, however, various theories about its possible causes. Some theories attribute the disorder to biological causes. Some of the possible biological causes include such prenatal complications as fetal malnutrition. Low birth weight or prematurity are thought to be possible causes, but there is no hard evidence supporting these claims.

Demographics

It is estimated that as many as 6% of children between the ages of five and 11 have developmental coordination disorder. Males and females are thought to be equally likely to have this disorder, although males may be more likely to be diagnosed. Developmental coordination disorder and speech-language disorders seem to be closely linked, although it is not clear why this is the case. Children with one disorder are more likely to have the other also.