Developmental coordination disorder

Developmental coordination disorder (DCD),^{[1][2][3][4][5]} also known as developmental dyspraxia or simply dyspraxia,^{[6][7][8][9][10]} is a chronic neurological disorder beginning in childhood that can affect planning of movements and co-ordination as a result of brain messages not being accurately transmitted to the body. Developmental coordination disorder is diagnosed in the absence of other neurological impairments like cerebral palsy,^[11] muscular dystrophy,^[6] multiple sclerosis or Parkinson's disease. It affects 5 to 6 percent of school-aged children.^[12] This disorder progresses to adulthood, therefore making it a lifelong condition.

Classification

Developmental coordination disorder is classified (by doctors) in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) as a motor disorder, in the category of neurodevelopmental disorders.^[13]

Signs and symptoms

Various areas of development can be affected by developmental coordination disorder and these will persist into adulthood,^[10] as DCD has no cure. Often various coping strategies are developed, and these can be enhanced through occupational therapy, psychomotor therapy, physiotherapy, speech therapy, or psychological training.

In addition to the physical impairments, developmental coordination disorder is associated with problems with memory, especially working memory.^[14] This typically results in difficulty remembering instructions, difficulty organizing one's time and remembering deadlines, increased propensity to lose things or problems carrying out tasks which require remembering several steps in sequence (such as cooking). Whilst most of the general population experience these problems to some extent, they have a much more significant impact on the lives of dyspraxic people.^[15] However, many dyspraxics have excellent long-term memories, despite poor short-term memory.^[15] Many dyspraxics benefit from working in a structured environment, as repeating the same routine minimises difficulty with time-management and allows them to commit procedures to long-term memory.

People with developmental coordination disorder sometimes have difficulty moderating the amount of sensory information that their body is constantly sending them, so as a result dyspraxics are prone to sensory overload and panic attacks.^[15]

Many dyspraxics struggle to distinguish left from right, even as adults, and have extremely poor sense of direction generally.

Moderate to extreme difficulty doing physical tasks is experienced by some dyspraxics, and fatigue is common because so much extra energy is expended while trying to execute physical movements correctly. Some (but not all) dyspraxics suffer from hypotonia, low muscle tone, which like DCD can detrimentally affect balance.^[2]

Gross motor control

Whole body movement and motor coordination issues mean that major developmental targets including walking, running, climbing and jumping can be affected. The difficulties vary from person to person and can include the following:

• Poor timing^[16]
• Poor balance^[16][17] (sometimes even falling over in mid-step). Tripping over one's own feet is also common.
• Difficulty combining movements into a controlled sequence.
• Difficulty remembering the next movement in a sequence.
• Problems with spatial awareness,^[17][18] or proprioception.
• Trouble picking up and holding onto simple objects such as pencils, owing to poor muscle tone or proprioception.
• "Clumsiness," to the point of knocking things over and bumping into people accidentally.
• Difficulty in determining left from right.
• Cross-laterality, ambidexterity, and a shift in the preferred hand are also common in people with developmental coordination disorder.
• Problems with chewing foods.

Fine motor control

Fine-motor problems can cause difficulty with a wide variety of other tasks such as using a knife and fork, fastening buttons and shoelaces, cooking, brushing one's teeth, styling one's hair, shaving,^[2][19] applying cosmetics, opening jars and packets, locking and unlocking doors, and doing housework.

Difficulties with fine motor co-ordination lead to problems with handwriting,^[2] which may be due to either ideational or ideo-motor difficulties.^[16][20] Problems associated with this area may include:

• Learning basic movement patterns.^[21]
• Developing a desired writing speed.^[19]
• Establishing the correct pencil grip^[19]
• The acquisition of graphemes – e.g. the letters of the Latin alphabet, as well as numbers.

Developmental verbal dyspraxia

Developmental verbal dyspraxia (DVD) is a type of ideational dyspraxia, causing speech and language impairments. This is the favoured term in the UK; however, it is also sometimes referred to as articulatory dyspraxia, and in the United States the usual term is childhood apraxia of speech (CAS).^[22][23][24]

Key problems include:

• Difficulties controlling the speech organs.
• Difficulties making speech sounds
• Difficulty sequencing sounds
  • Within a word
  • Forming words into sentences
• Difficulty controlling breathing, suppressing salivation and phonation when talking or singing with lyrics.
• Slow language development

Associated disorders and secondary consequences

People who have developmental coordination disorder may also have one or more of these co-morbid conditions:

• Attention deficit hyperactivity disorder (ADHD) (inattention, hyperactivity, impulsive behaviour).^[8][25][26]
• Autism spectrum disorder^{[26][27][28][29]}
• Dyscalculia (difficulty with mathematics),^[30]
• Dysgraphia (an inability to write neatly or draw),^[31]
• Dyslexia (difficulty with reading and spelling),^[32]:28
• Hypotonia (low muscle tone)^[2]
• Sensory processing disorder^[33][34]
• Specific language impairment (SLI)^[35]
• Visual perception deficits^[36]

However, they are unlikely to have all of these conditions. The pattern of difficulty varies widely from person to person, and it is important to understand that an area of major weakness for one dyspraxic can be an area of strength or gift for another. For example, while some dyspraxics have difficulty with reading and spelling due to an overlap with dyslexia, or numeracy due to an overlap with dyscalculia, others may have brilliant reading and spelling or mathematical abilities. Some estimates show that up to 50% of dyspraxics have ADHD.^[37]

Sensory processing disorder

Sensory Processing Disorder (SPD) concerns having abnormal oversensitivity or undersensitivity to physical stimuli, such as touch, light, sound, and smell.^[38] This may manifest itself as an inability to tolerate certain textures such as sandpaper or certain fabrics and including oral toleration of excessively textured food (commonly known as picky eating), or even being touched by another individual (in the case of touch oversensitivity) or may require the consistent use of sunglasses outdoors since sunlight may be intense enough to cause discomfort to a dyspraxic (in the case of light oversensitivity). An aversion to loud music and naturally loud environments (such as clubs and bars) is typical behavior of a dyspraxic individual who suffers from auditory oversensitivity, while only being comfortable in unusually warm or cold environments is typical of a dyspraxic with temperature oversensitivity. Undersensitivity to stimuli may also cause problems. Dyspraxics who are undersensitive to pain may injure themselves without realising.^[34] Some dyspraxics may be oversensitive to some stimuli and undersensitive to others.^[34]

Specific language impairment

Specific Language Impairment (SLI), research has found that students with developmental coordination disorder and normal language skills still experience learning difficulties despite relative strengths in language. This means that for students with developmental coordination disorder their working memory abilities determine their learning difficulties. Any strength in language that they have is not able to sufficiently support their learning.^[35]

Students with developmental coordination disorder struggle most in visual-spatial memory. When compared to their peers who don’t have motor difficulties, students with developmental coordination disorder are seven times more likely than typically developing students to achieve very poor scores in visual-spatial memory.^[39] As a result of this working memory impairment, students with developmental coordination disorder have learning deficits as well.^[40]

Psychological and social consequences

Psychological domain: Children with DCD struggle with lower self-efficacy and lower self-perceived competence in peer and social relations. They demonstrate greater aggressiveness and hyperactivity.^[41]

Social domain: Children are more vulnerable to social rejection and bullying, along with higher levels of loneliness.^[41]

Diagnosis

Assessments for developmental coordination disorder typically require a developmental history,^[7] detailing ages at which significant developmental milestones, such as crawling and walking,^[5][6][8] occurred. Motor skills screening includes activities designed to indicate developmental coordination disorder, including balancing, physical sequencing, touch sensitivity, and variations on walking activities.

Screening tests which can be used to assess developmental coordination disorder include:-

• Movement Assessment Battery for Children (Movement-ABC – Movement-ABC 2)^{[42][43][44][45][46]}
• Peabody Developmental Motor Scales- Second Edition (PDMS-2)^[42]
• Bruininks-Oseretsky Test of Motor Proficiency (BOTMP-BOT-2)^{[42][47][48][49]}
• Motoriktest für vier- bis sechsjährige Kinder (MOT 4-6)^[42][50]
• Körperkoordinationtest für Kinder (KTK)^[42]
• Test of Gross Motor Development, Second Edition (TGMD-2)^[42]
• Maastrichtse Motoriek Test (MMT)^[42]
• Wechsler Adult Intelligence Scale (WAIS-IV)
• Wechsler Individual Achievement Test (WAIT-II)
• Test of Word Reading Efficiency (TOWRE-2)

Currently there is no single gold standard assessment test.^[42]

A baseline motor assessment establishes the starting point for developmental intervention programs. Comparing children to normal rates of development may help to establish areas of significant difficulty.

However, research in the British Journal of Special Education has shown that knowledge is severely limited in many who should be trained to recognise and respond to various difficulties, including developmental coordination disorder, dyslexia and deficits in attention, motor control and perception (DAMP).^[8] The earlier that difficulties are noted and timely assessments occur, the quicker intervention can begin. A teacher or GP could miss a diagnosis if they are only applying a cursory knowledge.

"Teachers will not be able to recognise or accommodate the child with learning difficulties in class if their knowledge is limited. Similarly GPs will find it difficult to detect and appropriately refer children with learning difficulties."^[51]

Epidemiology

Developmental coordination disorder is a lifelong neurological condition that is more common in males than in females, with a ratio of approximately four males to every female. The exact proportion of people with the disorder is unknown since the disorder can be difficult to detect due to a lack of specific laboratory tests, thus making diagnosis of the condition one of elimination of all other possible causes/diseases. Approximately 5–6% of children are affected by this condition.^{[2][4][5][52]}

History

Collier first described developmental coordination disorder as 'congenital maladroitness'. A. Jean Ayres referred to developmental coordination disorder as a disorder of sensory integration in 1972,^[53][54] while in 1975 Dr Sasson Gubbay called it the 'clumsy child syndrome'.^[7][26][55] Developmental coordination disorder has also been called minimal brain dysfunction although the two latter names are no longer in use.

Other names include: Developmental Apraxia,^[7] Disorder of Attention and Motor Perception (DAMP)^[7][26] Dyspraxia,^[6] Developmental Dyspraxia,^[7] Motor Learning Difficulties,^[7][26] Perceptuo-motor dysfunction,^[7][26][54] Sensorimotor dysfunction.^[7]

The World Health Organisation currently lists developmental coordination disorder as Specific Developmental Disorder of Motor Function.^[6]

Notable cases

Living people who have publicly stated they have been diagnosed with developmental coordination disorder include actor Daniel Radcliffe,^[56] photographer David Bailey, actress Cara Delevingne,^[57] singer Florence Welch,^[58] and UK politician Emma Lewell-Buck.^[59]

See also

References

Further reading

• Human Movement Science (2003). "Developmental Coordination Disorder: Mechanisms, measurement and management". Human Movement Science. 22: 407–411. doi:10.1016/j.humov.2003.09.001. Retrieved 14 September 2013. 

External links

• Children with Developmental Coordination Disorder: At home, at school, and in the community – CanChild Centre McMaster University
• Developmental Verbal Dyspraxia – Pam Williams of Nuffield Hearing and Speech Centre
• UK Dyspraxia Foundation – What is dyspraxia?
• USA Dyspraxia Foundation – What is dyspraxia?