2003/08/01 by Robert Barnhart, Mary Jo Davenport, Susan Epps +1 · 472 citations
Psychology · Medicine · #Children's Physical and Motor Development #Infant Development and Preterm Care #Cerebral Palsy and Movement Disorders #Psychology #Motor coordination #Motor disorder #Apraxia #Physical medicine and rehabilitation #Motor skill #Spasticity #Developmental psychology #Motor impairment #Audiology #Cognitive psychology #Medicine #Psychiatry #Disease
paper · pdf · doi:10.1093/ptj/83.8.722
published in Physical Therapy 83(8), 722-731 (Oxford University Press)
openalex publication_date 2003/08/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
For the last 100 years, poor motor coordination in children has been recognized as a developmental problem.1 As early as 1937, these children were classified as “clumsy.”1 Since then, other terms such as “motorically awkward,” “motor impaired,” and “physically awkward” have been used to describe these children, and the terms “developmental apraxia” and “perceptual motor difficulties” have been used to characterize this developmental problem.2,3 Since the 1994 International Consensus Conference on Children and Clumsiness, the term “developmental coordination disorder” (DCD) has been used to describe the condition of children with motor incoordination.1,4 The purpose of this article is to provide the following information about DCD: (1) definition, (2) prevalence, (3) etiology, (4) discussion regarding the difficulties in classifying these children, (5) common characteristics, (6) long-term prognosis, and (7) brief review of treatment approaches. Developmental coordination disorder, a chronic and usually permanent condition found in children, is characterized by motor impairment that interferes with the child's activities of daily living and academic achievement.3,5 In order for a child to be diagnosed with DCD, these motor impairments must negatively affect some other aspect of his or her life.6 Impairment alone, however, does not qualify a child for the diagnosis of DCD; the motor impairment must not be caused by or have the symptoms of an identifiable neurological problem.2,5 That is, the child must not have any disturbances of muscle tone (ataxia or spasticity), sensory loss, or involuntary movements. If mental retardation is present, the testable IQ of the child must be greater than 70 and the motor impairments must be greater than what would normally be expected for children with mental retardation.5 Finally, a child diagnosed with DCD must not meet the criteria for a diagnosis of pervasive developmental disorder.6 Developmental coordination disorder appears to be a fairly common disorder of childhood and is usually identified in children between 6 and 12 years of age. Ten years ago, researchers7,8 estimated that DCD occurred in 10% to 19% of school-aged children. With a more precise definition of DCD, the current prevalence is estimated to be between 5% and 8% of all school-aged children,5,9–11 with more boys than girls (2:1) being diagnosed with DCD.12 This difference may reflect higher referral rates for boys, because the behavior of boys with motor incoordination may be more difficult to manage at home and in the classroom.8 In addition, a higher incidence of DCD may be found among children with a history of prenatal or perinatal difficulties.3 Due to the heterogeneity of DCD, finding its cause has been difficult.3 Several theories speculate that the etiology of DCD is part of the continuum of cerebral palsy5,13; is secondary to prenatal, perinatal, or neonatal insult3; or is secondary to neuronal damage at the cellular level in the neurotransmitter or receptor systems.14 Hadders-Algra14 based her view that DCD is a result of damage at the cellular level on evidence that cerebral palsy is often caused by prenatal damage that cannot be identified by current diagnostic techniques. Developmental coordination disorder, a chronic and usually permanent condition found in children, is characterized by motor impairment that interferes with the child’s activities of daily living. Although both standard and nonstandard functional tests are available to identify the specific disabilities experienced by a child with DCD, relating the observed disabilities to the primary impairment(s) or any possible neuropathology is not easily accomplished. The problems experienced by children with DCD are believed to emanate from abnormalities in neurotransmitter or receptor systems rather than from damage to specific groups of neurons or brain regions.15 Children's difficulties with coordination can result from a combination of one or more impairments in proprioception, motor programming, timing, or sequencing of muscle activity. A number of theories have evolved in an attempt to shed light on the specific neuronal processing deficits that contribute to DCD. Current models used to explain the neural regulation of posture and movement during development can serve as a basis for the examination and management of individuals with DCD. Using these models, many of the deficits of motor control observed in these children can be described. A variety of theoretical models exist to explain the role of the nervous system in motor development. Forty years ago, the primitive reflex model was a generally accepted theory used to explain how the brain regulates early motor behavior.16 As development proceeded, the higher centers exerted increasing control over the lower reflexes.16 These earlier models were based on a hierarchy of motor control in which higher centers were capable of planning and executing a motor plan without external or internal feedback from lower centers of the central nervous system (CNS). The more recently proposed systems model suggests a more complex interaction among various levels of the CNS. In the systems model, sensory feedback is interpreted by the CNS, and the appropriate movement strategy is selected based on current experience, the state of the internal and external environment, and memory of similar movements. Edelman's neuronal group selection theory includes aspects of both of these models and proposes that functional groups of neurons exist at all levels of the CNS.17 These neuronal groups are determined by evolution, but their functional integrity is dependent on afferent information produced by movement and experience.17 In this regard, these genetically determined collections of interconnected neurons (neuronal groups) in both cortical and subcortical structures serve as an early repertoire for motor behavior or receipt of specific sensory information.14,17,18 According to neuronal group selection theory, motor development proceeds in 2 phases.15 The first, the phase of primary variability, is characterized by crude and erratic motor activity that does not require sensory information for its initiation or guidance. These self-generated movements give rise to afferent (visual, kinesthetic) inputs that reinforce more specific synaptic connections within each group. An intermediate period in which effective patterns are selected is followed by the secondary variability phase. In this phase, sensory and motor factors interact to establish the intercellular connections that produce the specific and complex muscle contraction patterns that characterize coordinated, goal-directed movement. Reciprocal connections between groups subserving movements in various body parts and representing different parts of visual space are reinforced with each repetition of a particular function. As the more efficient movement patterns are practiced, the appropriate synaptic circuits are reinforced and subsequently established.14,17,19,20 The literature includes a wide variation in terminology and criteria to describe DCD. This variation has made studying the causes of DCD and developing treatment approaches for the child with DCD difficult. In their analysis of clinical trial data, Macnab et al21 identified 5 different subtype profiles of DCD. The first subtype included children with better gross motor than fine motor skills, although both were still below normal while standing balance and visual-perceptual skills were both within normal ranges. Compared with children of the same age with DCD, children in the second subtype scored high on measures of upper-limb speed and dexterity, visuomotor integration, and visual-perception skills, but they demonstrated poor performance on measures of kinesthetic ability (accuracy in discriminating movement and position of the upper limbs) and balance. Children in subtype 3 demonstrated the greatest overall motor involvement and were the only subtype to have difficulty with both kinesthetic and visual skills. Compared with their peers with DCD, children in subtype 4 performed well on kinesthetic tasks but demonstrated poor performance on tasks requiring visual and dexterity skills. Children in subtype 5 demonstrated poor performance on measurements of running speed and agility compared with their peers with DCD; however, they performed well relative to their peers with DCD in the tasks involving visual-perception skills. The development of different classification systems for DCD may have been influenced by the design of motor tests.21 For example, items testing one motor skill may be influenced by a related motor skill (eg, ball-throwing skills cannot be separated from visuomotor skills). In addition, a test may have an over-representation of one skill that could unduly influence the child's performance on the test. For example, having a greater number of items testing gross motor rather than fine motor skills could either positively or negatively influence a child's score, depending on the child's specific strengths and weaknesses. Another difficulty in interpreting the literature on DCD is the lack of inclusion criteria. Geuze et al22 reviewed 164 publications on the study of DCD and found that only 60% of the studies had objective inclusion criteria. Because of this lack of inclusion criteria, Geuze et al recommended that a child scoring below the 15th percentile on standardized tests of motor skills and having an IQ score above 69 would qualify for a diagnosis of DCD. The inconsistency among standardized motor tests used to identify children with DCD is another problem. In one study,5 the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP) and the Movement Assessment Battery for Children (M-ABC) were administered to 157 children with DCD and 155 children with no motor difficulties; the test results were in agreement 82% (kappa=.62) of the time in distinguishing children who had DCD from children who did not have DCD. This is considered a substantial level of agreement.23 In a study of 202 children (101 with DCD and 101 without DCD), the BOTMP and M-ABC agreed only 67% of the time (kappa=.41), which was considered a moderate level of agreement.24 Because the BOTMP and the M-ABC are 2 of the most commonly used tests for identifying children with DCD, the potential lack of agreement by these tests in identifying children who have DCD is a concern. Two primary factors may explain the difference in outcomes between the BOTMP and M-ABC when used to identify children with DCD.24 First, the BOTMP allows the tester to verbally prompt and correct the child during the testing procedure, allowing the child who is dependent on more external controls to do better on the BOTMP. The BOTMP tends to under-identify children with DCD. Second, the M-ABC requires more careful instruction on the part of the examiner and allows more opportunities for the examinee to practice, but does not allow any verbal or physical prompting by the examiner. Children with attention problems may have more difficulty with the careful instructions for the M-ABC. Another difficulty in classifying children with DCD is the overlap with other disorders. Approximately 41% of children with attention-deficit/hyperactivity disorder (ADHD) and 56% of children with learning disabilities also have DCD.5,21 Further confusing the classification scheme is that the terms “developmental coordination disorder,” for which no identifiable organic brain damage is present, and “apraxia,” which is caused by identifiable brain damage, have been used interchangeably.3 Children with DCD may have a wide range of dysfunctions. These dysfunctions can be grouped into 3 areas: gross motor, fine motor, and psychosocial. Many children with DCD have neurological soft signs such as hypotonia, persistence of primitive reflexes, and immature balance reactions that interfere with gross motor development.5,25 These children also may demonstrate an awkward running pattern, fall frequently, drop items, and have difficulty imitating body positions and following 2- to 3-step motor commands.8 Because of their gross motor problems, children with DCD also perform poorly in sporting events,2 possibly due, in part, to their slow reaction and movement times.7 Their decreased participation in sports may result in decreased muscle force.8 Difficulty with handwriting or drawing often is the first identifiable sign of a fine motor problem and is the most frequently mentioned motor problem experienced by children with DCD. Children with DCD frequently have difficulty planning and executing other fine motor skills such as gripping and dressing.26–29 Unfortunately, children with DCD may experience problems not limited to fine or gross motor areas. These children also may experience psychosocial problems at school. Children with DCD may have learning disabilities or reading problems and may be at increased risk for lower intelligence.5,8 They may act out in class more than other children,13 may be the class clown, and may exhibit less socially desirable means of gaining recognition and friends.8 Adolescents with DCD have been found to have fewer friends, and they have more feelings of low self-worth and more anxiety than peers without DCD and younger children with DCD.30 Historically, parents have been told not to worry about their child's clumsiness because the child will outgrow the problem.31 However, current researchers in the area of DCD report that the children do not outgrow clumsiness and that, without intervention, they will not improve.1,8,12,27,31 Losse et al31 tested 17 children aged 6 years and retested them at age 16 years. The children with motor difficulties at 6 years of age continued to exhibit problems at 16 years of age. In another study,32 818 children with DCD were tested for reading comprehension at age 7 years and then again at age 10 years. A positive correlation in poor reading comprehension existed for children with DCD at 7 and 10 years of age. A follow-up study was conducted on 22-year-old individuals (N=55) who at age 7 years had either DCD or attention-deficit/hyperactivity disorder (ADHD), or both.33 The children with DCD and those with both DCD and ADHD had poorer outcomes than their similarly aged peers without DCD and children with ADHD only. The children with DCD and those with both DCD and ADHD were found to have had more criminal offenses, more incidences of substance abuse and other psychiatric disorders, and lower levels of schooling. Treatment approaches used by occupational therapists and physical therapists can be broadly categorized into either bottom-up or top-down approaches (Tab. 1).10,12,34–36 Bottom-up approaches are based on hierarchical theories of motor control. These theories tend to explain the remediation of motor dysfunction through activation of higher levels of neuronal functioning in a child. The bottom-up approaches frequently used in managing children with DCD are sensory integration, the process-oriented treatment approach, and perceptual motor training.34 Summary of Bottom-Up Versus Top-Down Approaches Summary of Bottom-Up Versus Top-Down Approaches In sensory integration therapy, the child is provided sensory stimulation designed to promote motor development and higher cortical learning. A child undergoing sensory integration therapy may show some gains in motor development, but these gains often do not generalize to functional skills.34 Kinesthesia (the perception of one's own body parts, weight, and movement) is integral to the acquisition of motor skills in process-oriented treatment approaches. Therapeutic intervention with process-oriented treatment is based on specifically designed kinesthetic training activities. As described by Laszlo and Bairstow,37 this approach has an inherent reward system built into it through its use of positive reinforcement, presentation of desirable activities within the capabilities of the child, and judicious progression of the level of difficulty. The usefulness of the process-oriented treatment approach has been the subject of considerable study.9,10,37,38 Sims and colleagues35 suggested that much of the success of this approach can be attributed to a strong motivation effect, fostered by positive feedback and a sense of self-competence. Perceptual motor training, an eclectic approach, offers the child with DCD a wide range of motor experiences along with ample opportunities to practice these skills. Often, in outcome studies, children who receive perceptual motor training are compared with children who receive either sensory integration therapy or process-oriented treatment. Children perceptual motor training have been found to demonstrate motor to or greater than those of children either sensory integration therapy or process-oriented perceptual motor training, process-oriented may promote learning through positive feedback and reinforcement, these do not and to the that top-down approaches approaches use a approach to motor skill development and have been influenced by the systems approach to motor learning and control. This approach suggests that motor skills from an interaction of many both internal and external to the approaches also the in which motor behavior intervention and approaches or are the 2 most commonly intervention on of a The theoretical for intervention in a child's motor performance is the result of learning on a specific Motor tasks are into with each and then to the Children with this approach have demonstrated gains in motor skills.34 approaches to motor development problem The approach strategy the to to the and perform the well did plan The child verbal to the to motor learning. In this approach, the as a by the child out how to his or her motor performance on various motor intervention, the results of studies of approaches are In one 10 children with DCD who were with a approach to motor development were compared with 10 children who were with a bottom-up The children were for and groups on various standardized motor tests 10 treatment However, children in the approach group motor skill and to better than children who were the bottom-up and the approach both provide repetition and practice of specific motor skills, and the approach has the of problem The greater success of top-down when compared with bottom-up be a result of the top-down inclusion of both and motor learning with for attention to and memory as the child in activities. The results of these studies, in to outcome measures of the different approaches in children with DCD, would that approaches that systems theory on sensory information being only part of the and motor learning theory be most effective for these 2 a brief of clinical the of various treatment approaches used with children with of Treatment Approaches for Children With Developmental approach to daily occupational performance treatment approach treatment group integration, perceptual motor, gross and fine motor integration Assessment Battery for Test of Motor Test of for of Motor and of of Treatment Approaches for Children With Developmental approach to daily occupational performance treatment approach treatment group integration, perceptual motor, gross and fine motor integration Assessment Battery for Test of Motor Test of for of Motor and of The neuronal group selection theory can provide a for interpreting the in outcomes among the various approaches. children with moderate to cerebral palsy have a limited repertoire of primary neuronal which children with DCD are believed to experience difficulty at the level of secondary variability, that is, in and the most efficient and effective for a normal development, experience a primary role in the neuronal group selection that the for and According to the neuronal group selection theory, this of motor skill during the of secondary variability as a result of of neuronal selection of specific neurons within each repetition of synaptic within and among neuronal and sensory synaptic which act in and cortical and subcortical and following to a variety of motor of these connections is dependent on sensory Bottom-up approaches such as sensory integration, process-oriented and perceptual motor training sensory experience, with less on processing and motor Although an intervention based on information processing may provide the experience to the most effective neuronal bottom-up approaches may not provide for motor practice of and goal-directed tasks in order to reinforce and establish these approaches less on the specific impairments to decreased coordination and more on the of that is, the among a number of structures and systems and the within which the is Treatment based on a top-down approach that provide the child the to in problem while afferent subcortical structures the feedback and to identify and the most efficient movement for the Because integration, internal of motor and appropriate motor at the level of secondary the on sensory rather than factors by the bottom-up approaches in part, be for the observed in outcomes following treatment. A number of motor learning theories have been proposed in an attempt to explain the through which are into more complex According to the motor control and learning theory proposed by and motor circuits that the and following long-term these and functioning neuronal circuits through practice, the child is to motor into more complex movements. and proposed 2 to such the first of which on sensory to neuronal is during the second that the to the specific motor tasks through the and involving the and in the first of learning requires attention and The motor then in the of learning through repetition and top-down approaches meet both of these bottom-up approaches information processing only. the and of the neural in children with DCD is a not Motor control are complex and on functioning of and motor only are children with DCD a group in terms of functional disabilities the specific of the problems observed can from one child to the Because of these an approach to the management of children with DCD is Developmental coordination disorder is a complex disorder 5% to of school-aged children. intervention, these children will to exhibit poor motor skills and show deficits in other as for may (1) the most appropriate level of intervention (2) which produce results that generalize to the and provide long-term in motor (3) what have on the child's motor and (4) motor skills to the that to the