Developmental coordination disorder is diagnosed only if the impairment in motor skills significantly interferes with the performance of, or participation in, daily activities in family, social, school, or community life (Criterion B). Examples of such activities include getting dressed, eating meals with age-appropriate utensils and without mess, engaging in physical games with others, using specific tools in class such as rulers and scissors, and participating in team exercise activities at school. Not only is ability to perform these ac- tions impaired, but also marked slowness in execution is common. Handwriting compe- tence is frequently affected, consequently affecting legibility and / or speed of written output and affecting academic achievement (the impact is distinguished from specific learning difficulty by the emphasis on the motoric component of written output skills). In adults, everyday skills in education and work, especially those in which speed and accuracy are required, are affected by coordination problems.
Criterion C states that the onset of symptoms of developmental coordination disorder must be in the early developmental period. However, developmental coordination disorder is typically not diagnosed before age 5 years because there is considerable variation in the age at acquisition of many motor skills or a lack of stability of measurement in early childhood (e.g., some children catch up) or because other causes of motor delay may not have fully manifested.
Criterion D specifies that the diagnosis of developmental coordination disorder is made if the coordination difficulties are not better explained by visual impairment or at- tributable to a neurological condition. Thus, Visual function examination and neurological examination must be included in the diagnostic evaluation. If intellectual disability (intel- lectual developmental disorder) is present, the motor difficulties are in excess of those ex- pected for the mental age; however, no IQ cut-off or discrepancy criterion is specified.
Developmental coordination disorder does not have discrete subtypes; however, indi- viduals may be impaired predominantly in gross motor skills or in fine motor skills, in- cluding handwriting skills.
Other terms used to describe developmental coordination disorder include childhood dyspraxia, specific developmental disorder of motorfunction, and clumsy child syndrome.
Some children with developmental coordination disorder show additional (usually sup- pressed) motor activity, such as choreiform movements of unsupported limbs or mirror movements. These ”overﬂow” movements are referred to as neurodevelopmental immatu rities or neurological soft signs rather than neurological abnormalities. In both current literature and clinical practice, their role in diagnosis is still unclear, requiring further evaluation.
The prevalence of developmental coordination disorder in children ages 5—11 years is 5%— 6% (in children age 7 years, 1.8% are diagnosed with severe developmental coordination disorder and 3% with probable developmental coordination disorder). Males are more of- ten affected than females, with a malezfemale ratio between 2:1 and 7:1.
The course of developmental coordination disorder is variable but stable at least to 1 year follow-up. Although there may be improvement in the longer term, problems with coor— dinated movements continue through adolescence in an estimated 50%—70% of children.
Onset is in early childhood. Delayed motor milestones may be the first signs, or the disor- der is first recognized when the child attempts tasks such as holding a knife and fork, but- toning clothes, or playing ball games. In middle childhood, there are difficulties with motor aspects of assembling puzzles, building models, playing ball, and handwriting, as well as with organizing belongings, when motor sequencing and coordination are re- quired. In early adulthood, there is continuing difficulty in learning new tasks involving complex/automatic motor skills, including driving and using tools. Inability to take notes and handwrite quickly may affect performance in the workplace. Co-occurrence with other disorders (see the section ”Comorbidity” for this disorder) has an additional impact on presentation, course, and outcome.
Environmental. Developmental coordination disorder is more common following pre- natal exposure to alcohol and in preterm and low-birth-weight children.