Genetic and physiological. Impairments in underlying neurodevelopmental processes— particularly in visual-motor skills, both in visual-motor perception and spatial mentalizing— have been found and affect the ability to make rapid motoric adjustments as the complexity of the required movements increases. Cerebellar dysfunction has been proposed, but the neural basis of developmental coordination disorder remains unclear. Because of the co-occurrence of developmental coordination disorder with attention-deficit/hyperactivity disorder (ADHD), specific learning disabilities, and autism spectrum disorder, shared genetic effect has been pro- posed. However, consistent co-occurrence in twins appears only in severe cases.
Course modifiers. Individuals with ADHD and with developmental coordination dis- order demonstrate more impairment than individuals with ADHD without developmen- tal coordination disorder.
Developmental coordination disorder occurs across cultures, races, and socioeconomic conditions. By definition, "activities of daily living” implies cultural differences necessi— tating consideration of the context in which the individual child is living as well as whether he or she has had appropriate opportunities to learn and practice such activities.
Developmental coordination disorder leads to impaired functional performance in activ- ities of daily living (Criterion B), and the impairment is increased with co-occurring con- ditions. Consequences of developmental coordination disorder include reduced participation in team play and sports; poor self—esteem and sense of self—worth; emotional duced physical activity and obesity.
Motor impairments due to another medical condition. Problems in coordination may be associated with visual function impairment and specific neurological disorders (e.g., cerebral palsy, progressive lesions of the cerebellum, neuromuscular disorders). In such cases, there are additional findings on neurological examination.
Intellectual disability (intellectual developmental disorder). If intellectual disability is present, motor competences may be impaired in accordance with the intellectual disabil- ity. However, if the motor difficulties are in excess of what could be accounted for by the intellectual disability, and criteria for developmental coordination disorder are met, de— velopmental codrdination disorder can be diagnosed as well.
Attention-deficit/hyperactivity disorder. Individuals with ADHD may fall, bump into objects, or knock things over. Careful observation across different contexts is required to ascertain if lack of motor competence is attributable to distractibility and impulsiveness rather than to developmental coordination disorder. If criteria for both ADHD and devel- opmental coordination disorder are met, both diagnoses can be given.
Autism spectrum disorder. Individuals with autism spectrum disorder may be uninter- ested in participating in tasks requiring complex coordination skills, such as ball sports, which will affect test performance and function but not reﬂect core motor competence. Co- occurrence of developmental coordination disorder and autism spectrum disorder is com- mon. If criteria for both disorders are met, both diagnoses can be given.
Joint hypermobility syndrome. Individuals with syndromes causing hyperextensible joints (found on physical examination; often with a complaint of pain) may present with symptoms similar to those of developmental coordination disorder.
Disorders that commonly co-occur with developmental coordination disorder include problems of inattention, including ADHD (the most frequent coexisting condition, with problems; and joint hypermobility syndrome. Different clusters of co-occurrence may be present (e.g., a cluster with severe reading disorders, fine motor problems, and handwriting problems; another cluster with impaired movement control and motor planning). Presence testing more difficult and may independently interfere with the execution of activities of daily living, thus requiring examiner judgment in ascribing impairment to motor skills.
Diagnostic Criteria 307.3 (F98.4)
A. Repetitive, seemingly driven, and apparently purposeless motor behavior (e.g., hand shaking or waving, body rocking, head banging, self-biting, hitting own body).
B. The repetitive motor behavior interferes with social, academic, or other activities and may result in seIf-injury.
C. Onset is in the early developmental period.