Developmental Coordination Disorder (DCD)

Essentials

• In children,physical activity is of central importance in playing and in the formation of peer relations throughout preschool age and the period of growth.
• Children with developmental coordination disorder (DCD) often have additional special developmental problems, which are important to consider when planning any supportive action. Delayed speech and linguistic development, problems in fine motor functions and attention deficits are common associated symptoms.
• Supportive measures should be directed at motor training and minimizing associated problems but also at supporting the development of a healthy self-esteem.
• Children with coordination disorder are mostly treated in primary health care.
• Assessment in specialized care is necessary for children whose motor difficulties are suspected to be caused by a myopathy or mild CP or who have symptoms that are so extensive as to make the supportive measures available in primary health care insufficient.

Normal motor development

• Children usually
  • learn to walk independently by the age of 18 months
  • take running steps and shift their body weight when kicking a big ball at the age of 2
  • can jump on two feet and rise up on their toes when asked to do so at the age of 3
  • can walk on their toes and walk a few steps along a line, can stand on one foot for a moment and climb stairs taking steps alternately with both feet at the age of 4
  • can jump several times consecutively on one foot and walk accurately along a line at the age of 5
  • can ride a two-wheeled bike, ski and skate at preschool and school age.

Definitions and prevalence

• Developmental coordination disorder (DCD) is a neurobiological disorder with a heterogeneous symptom picture. It often manifests with cognitive developmental disorders, learning difficulties or neuropsychiatric disorders.
• Aetiology is multifactorial. No underlying neurological disease or injury can be identified and motor difficulties are not explained by mental retardation, visual impairment or lack of training opportunities.
• According to current hypothesis, a child with DCD has difficulties in forming and storing mental images (motor imagery) regarding the motor models of motor functions and movement sequences, and/or in the efficient use of proprioceptive feedback to carry out and correct a movement sequence. This has repercussions for balance maintenance, coordination, automatization of motor actions, and for motor learning.
• The importance of cognitive control becomes emphasized as movements/movement sequences become more difficult.
• In brain imaging, DCD has been associated with abnormalities in both the brain structure and function.
• The prevalence of DCD is 5-6% in school age children.
• The disorder is more common in boys (2:1-7:1). The risk of the disorder is 6 to 8 times higher in preterm or low-weight infants.
• The problems are long-standing but not progressive. In some children motor difficulties persist into adolescence and adult age.

Clinical picture

• Coordination disorder appears as difficulties in planning and learning new motor skills starting from the first years of life and in executing coordinated motor actions in a smooth and precise manner.
• Problems may occur in gross, fine as well as visual motor functions.
• During the first years of life, the symptoms may present as delayed independent walking or difficulty in learning more demanding motor skills, such as running, climbing, standing or jumping on one foot, riding a bicycle, catching a ball, buttoning up one's clothes, tying shoelaces, cutting with scissors, building with blocks, copying figures or writing by hand.
• The problem may also appear as balance problems when turning, or as stumbling on stairs, bumping into things, rigidity in running or jumping, or difficulties in force regulation or dropping things. The stabilization of handedness may be delayed (at the age of over 4 years) or remain not stabilized.
• As a consequence, there are difficulties in managing skills relevant for independent functioning in daily life or participating in age-appropriate motor activities.

Associated disorders

• Compared to the average, children with DCD have more often specific disorders of cognition and learning, as well as problems related to social perception, behaviour or emotions, and their performance in school is poorer.
  • Developmental speech and language disorder
  • Dyslexia
  • Developmental mathematics disorder
  • Attention deficit hyperactivity disorder (ADHD)
  • Challenges in social skills, autism spectrum disorder (ASD)
  • Nonverbal learning disorder syndrome (NLD)
• Due to the high probability of associated disorders in children with DCD, it is important to specify their extent and to address them early enough.
• DCD is diagnosed in as many as 70% of children with developmental speech and language disorder.
• Developmental speech, writing and mathematics disorders are common in school age children.
• ADHD appears in up to 50% of children with DCD.
• Accumulation of disorders will worsen a child's prognosis.
• Particular attention should be paid to social and emotional development in children with DCD, boys in particular.
• Due to motor problems, children with DCD tend to avoid physical exercise and participation in team sports, which may lead to withdrawal and problems with self-esteem.
• Anxiety and behavioural problems have been interpreted as results of long-standing daily negative experiences and experiences of being inferior.
• As a result of low level of physical exercise, DCD is associated with a risk of obesity problems.
• In over a half of children the difficulties associated with DCD persist into adult age and, as a result, socio-emotional difficulties, low level of physical activity and obesity problems are common in them.

Diagnosis

• The diagnosis is based on:
  1. clinical assessment
  2. assessment of functional capacity in daily life
  3. testing of motor skill level.
• The diagnosis may be made in children of 5 years of age or older.
• Some children with developmental delays will reach their age-appopriate skills later (late/slow maturers).

1. Clinical assessment

• As regards the patient history, the following should be investigated: pre- and perinatal risk factors (smoking and alcohol use during pregnancy, fetal growth disturbance, prematurity, perinatal lack of oxygen) as well as hereditary and environmental factors.
• Exclusion of neurological diseases causing motor disturbances (e.g. CP, myopathies, peripheral nervous disorders), and of visual handicap and mental retardation.
• Neurological examination
  • In cerebral palsy (CP), typical findings include increasing muscle tone and spasticity, increase of tendon reflexes and positive Babinski sign.
    • In ataxic CP syndrome the difficulties in balance and motion control are emphasized, the child often has intention tremor and nystagmus.
    • Balance problems are common in children with DCD, but other aforementioned signs are not detected.
  • Muscle weakness and diminished or absent tendon reflexes are typical for neuromuscular diseases.
    • Children with DCD may be hypotonic but their muscle strength and tendon reflexes are normal, as opposed to children with myopathy.
    • In children with neuromuscular disease, muscle weakness can be detected when the child stands up from the supine position; due to weak trunk muscles, the child gets up supporting him/herself with hands against the thighs.
• Further differential diagnostic examinations can be carried out as clinically indicated.
  • If a myopathy is suspected, plasma creatine kinase should be measured.
  • Examinations in specialized care include, for example, electroneuromyography or, if CP is suspected, brain MRI.
• Somatic diseases, such as rheumatoid arthritis, hypothyroidism and obesity may affect motor performance.
• Investigate possible associated symptoms.

2. Assessment of functional capacity in daily life

• Clinical assessment should, additionally, consider the following:
  • To what extent does the coordination disorder prevent the child from participating in age-appropriate activities at home or elsewhere?
  • Do the problems cause the child any other disadvantage?
• Occurrence of similar problems in other members of the family or close relatives may provide useful further information on the development of the problem with age.
• Structured questionnaires may be used in addition to interviewing the parents.
  • Feedback from the day care centre or school provides information on the child's skills and progress compared to peers and how the child copes and participates in the group.

3. Motor testing

• The diagnosis of DCD requires the use of standardized motor testing (recommendation by European Academy of Childhood Disability, EACD, updated in 2019).
  • The Movement-ABC-2 test (MABC-2, 3 to 16 years) measures fine motor and ball skills as well as static and dynamic balance (see e.g. http://www.psychometrics.cam.ac.uk/services/psychometric-tests/mabc-ii).
  • The Bruininks-Oseretsky test (BOT-2, 4 to 21 years) measures fine motor skills, coordination as well as strength and agility, and it can also be used.
  • The cut-off limit for DCD in MABC-2 is scoring < 16th percentile (1 SD).
  • The same tests can also be used to follow up on rehabilitation.

Rehabilitation

• Early observation of and support for detected problems in motor development are, in the most natural way, realized in day care and/or associated with child health clinics already before the DCD diagnosis has been made.
• Children with DCD may need help with daily tasks, such as eating (e.g. peeling boiled potatoes) or dressing (buttoning up, tying shoelaces).
• If problems are challenging or extensive, rehabilitation must be considered to improve the child's possibilities for participation.
• The targets should always be defined individually with the child and his/her parents.
• In some cases, compensatory action and support from the environment may be sufficient.
• If the child has significant difficulties with fine motor functions and writing by hand, a computer is recommended as a writing aid at shool when the amount of material to be written increases.
• In addition to therapy, support from parents and teachers for regular daily training at home is important for achieving skills and applying them in the daily environment.