Developmental motor coordination disorder

Essential (Required) Features:

• Significant delay in the acquisition of gross or fine motor skills and impairment in the execution of coordinated motor skills manifesting as clumsiness, slowness, or inaccuracy of motor performance.
• Coordinated motor skills are markedly below that expected on the basis of age.
• Onset of coordinated motor skill difficulties occurs during the developmental period and is typically apparent from early childhood.
• Coordinated motor skills difficulties cause significant and persistent limitations in activities of daily living, school work, vocation and leisure activities, or other important areas of functioning.
• Difficulties with coordinated motor skills are not are not better accounted for by a Disease of the Nervous System, Disease of the Musculoskeletal System or Connective Tissue, sensory impairment, or a Disorder of Intellectual Development.

Additional Clinical Features:

• Young children with Developmental Motor Coordination Disorder may be delayed in achieving motor milestones (e.g., sitting, crawling, walking), although many achieve typical early motor milestones. Acquisition of skills such as negotiating stairs, pedalling, buttoning shirts, completing puzzles, tying shoes, and using zippers may be delayed or pose difficulties. Even when a given skill is achieved, movement execution may appear awkward, slow, or less precise than that of peers. Children may drop things, stumble, bump into obstacles, or fall more frequently than peers.
• Developmental Motor Coordination Disorder may affect primarily gross motor functioning, primarily fine motor functioning, or both aspects of motor functioning.
• Manifestations of Developmental Motor Coordination Disorder typically persist into adult life. Older children and adults with Developmental Motor Coordination Disorder may be slow or inaccurate in a variety of activities requiring fine or gross motor skills, such as team sports (especially ball sports), bicycling, handwriting, assembling models or other objects, or drawing maps.
• Other Neurodevelopmental Disorders commonly co-occur with Developmental Motor Coordination Disorder. In addition to Disorders of Intellectual Development, Attention Deficit Hyperactivity Disorder, and Autism Spectrum Disorder (see above), this also includes Developmental Speech Sound Disorder (particularly difficulties with articulation), Developmental Language Disorder and Developmental Learning Disorder. Although the presence of other Neurodevelopmental Disorders does not preclude the diagnosis of Developmental Motor Coordination Disorder, these disorders may also interfere with the execution of activities of daily living, school work, and vocational and leisure activities that require coordinated motor skills. Co-occurrence therefore complicates assessment and requires clinical judgment in attributing limitations in activities that require coordinated motor skills to a specific diagnosis.

Boundary with Normality (Threshold):

• There is considerable variation in the age of acquisition of many motor skills and a lack of stability of measurement in early childhood. Onset of Developmental Motor Coordination Disorder typically occurs during the early developmental period, but differentiation from typical development before the age of 4 years is difficult due to the variability in motor development and skill acquisition throughout early childhood. Therefore, the diagnosis of Developmental Motor Coordination Disorder is usually not made before 5 years of age.
• Performance of motor skills should ideally be assessed using appropriately normed, individually administered, culturally appropriate standardized tests of gross and fine motor coordination, and should include evaluation of the impact of symptoms at home and at school (or, in adults, in the work place). Key features for assessment are persistence of motor skill impairment over time, severity of impairment, and pervasiveness of impact on functioning.
• Developmental Motor Coordination Disorder often co-occurs with other Neurodevelopmental Disorders. Attention Deficit Hyperactivity Disorder is most common (an estimated 50% of cases), as well as Developmental Speech and Language Disorder, Developmental Learning Disorder (most often with impairments in reading and written expression), and Autism Spectrum Disorder.

Course Features:

• Though there may be improvement in symptoms over time with some children experiencing a complete remission of symptoms, the course of Developmental Motor Coordination Disorder is typically chronic, persisting into adolescence and adulthood in up to 50 – 70% of cases. The persistence of Developmental Motor Coordination Disorder into adulthood often impacts social and psychological functioning as well as physical health.
• The presence of other co-occurring Neurodevelopmental Disorders, such as Attention Deficit Hyperactivity Disorder, may further complicate the course of Developmental Motor Coordination Disorder. Individuals with co-occurring disorders typically experience more impairment than individuals with a single diagnosis.

Developmental Presentations:

• The prevalence of Developmental Motor Coordination Disorder is approximately 5 – 6% of school-aged children (5–11 years), though up to 10% of children may have less severe difficulties with motor skills that still impact academic and social functioning.
• The manifestation of Developmental Motor Coordination Disorder symptoms varies with developmental stage:
• Preschool: In preschool children, delays in meeting one or more motor milestones (e.g., sitting, crawling, walking) or in developing specific skills (e.g., climbing stairs, buttoning clothing, tying shoes) may be evident.
• Middle Childhood: In middle childhood, symptoms may be evident in activities such as handwriting, playing with a ball, or building puzzles or models.
• Adolescence and adulthood: By adolescence, difficulties in motor coordination may manifest in attempts to master new skills, such as driving, using tools, or note taking.
• Across all developmental stages, even once a skill is acquired, the execution of movements tends to be more awkward and less precise than in typically developing peers.
• Children with Developmental Motor Coordination Disorder may also be at increased risk of co-occurring disruptive behaviour problems, anxiety, and depression. In addition, children with Developmental Motor Coordination Disorder tend to report lower levels of self-efficacy and competence in physical and social abilities, and are at heightened risk of becoming overweight or obese as compared to their typically developing peers.

Sex- and/or Gender-Related Features:

• Developmental Motor Coordination Disorder more frequently affects boys, with a ratio of between 2:1 to 7:1.

Boundaries with Other Disorders and Conditions (Differential Diagnosis):

• Boundary with Disorders of Intellectual Development: Individuals with Disorders of Intellectual Development may exhibit delays in acquisition and impairment in the execution of coordinated motor skills, along with decrements in general intellectual functioning and adaptive behaviour. If the diagnostic requirements of a Disorder of Intellectual Development are met and coordinated motor skills are significantly below what would be expected based on level of intellectual functioning and adaptive behaviour, both diagnoses may be assigned.
• Boundary with Autism Spectrum Disorder: In Autism Spectrum Disorder, there may be reluctance to participate in tasks requiring complex motor coordination skills, such as ball sports, which is better accounted for by a lack of interest rather than any specific deficits in motor coordination.
• Boundary with Attention Deficit Hyperactivity Disorder: Co-occurrence of Developmental Motor Coordination Disorder and Attention Deficit Hyperactivity Disorder is common. Both diagnoses may be assigned if the diagnostic requirements of both are met. However, some individuals with Attention Deficit Hyperactivity Disorder may appear to be clumsy (e.g., bumping into obstacles, knocking things over) due to distractibility and impulsiveness. Developmental Motor Coordination Disorder should not be diagnosed in such cases.
• Boundary with Diseases of the Nervous System, Diseases of the Musculoskeletal System or Connective Tissue, and sensory impairment: Motor skills may be affected by Diseases of the Nervous System (e.g., cerebral palsy, muscular dystrophy), Diseases of the Musculoskeletal System or Connective Tissue, sensory impairment (especially severe visual impairment), or joint hypermobility, which are established by appropriate physical and laboratory examination. A diagnosis of Developmental Motor Coordination Disorder should not be assigned when the difficulties with motor coordination are solely attributable to one of these conditions. Some children with Developmental Motor Coordination Disorder show atypical motor activity (usually suppressed), such as choreiform movements of unsupported limbs or mirror movements. These ‘overflow’ movements are not considered Diseases of the Nervous System per se and do not exclude the diagnosis of Developmental Motor Coordination Disorder.
• Boundary with effects of psychosocial deprivation: Extreme psychosocial deprivation in early childhood can produce impairments in motor functions. Depending on the onset, level of severity and duration of the deprivation, motor functioning may improve substantially after the child is moved to a more positive environment. However, some deficits may persist even after a sustained period in an environment that provides adequate stimulation for development, and a diagnosis of Developmental Motor Coordination Disorder may be appropriate in such cases if all diagnostic requirements are met.