Developmental coordination disorder. (Update).

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.

Definition of DCD

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?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)

[Barnhart RC, Davenport MJ, Epps SB, Nordquist VM. Developmental coordination disorder. Phys Ther. 2003;83:722-731.]

Key Words: Developmental coordination disorder.

Prevalence

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, researchers (7,8) 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)

Etiology

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 palsy (5,13); is secondary to prenatal, perinatal, or neonatal insult (3); or is secondary to neuronal damage at the cellular level in the neurotransmitter or receptor systems. (14) Hadders-Algra (14) 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.

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)

Difficulties in Classifying Children With DCD

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 al (21) 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 al (22) 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)

Characteristics of Children With DCD

Children with DCD may have a wide range of dysfunctions. These dysfunctions can be grouped into 3 areas: gross motor, fine motor, and psychosocial.

Gross Motor

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)

Fine Motor

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)

Psychosocial

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)

Prognosis

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 al (31) 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

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)

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 colleagues (35) 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 receiving perceptual motor training have been found to demonstrate motor improvements equal to or greater than those of children receiving either sensory integration therapy or process-oriented treatment. (34) While perceptual motor training, like process-oriented treatment, may promote learning through positive feedback and reinforcement, these techniques do not facilitate cognitive and problem-solving strategies to the extent that top-down approaches do.

Top-down approaches typically use a problem-solving approach to motor skill development and have been greatly influenced by the dynamic systems approach to motor learning and control. This approach suggests that motor skills develop from an interaction of many systems, both internal and external to the child. (39) Topdown approaches also emphasize the context in which motor behavior occurs. Task-specific intervention and cognitive approaches or strategies are the 2 most commonly used.

Task-specific intervention focuses on direct teaching of a skill. The theoretical foundation for task-specific intervention in a child's motor performance is the result of learning focused on a specific task. Motor tasks are broken down into steps, with each step taught independently and then organized to accomplish the entire task. (34) Children managed with this approach have demonstrated gains in motor skills. (34)

Cognitive approaches to motor development emphasize active problem solving. (36) The cognitive approach strategy involves the GPDC framework:

Goal: What am I going to do?

Plan: How am I going to accomplish the skill?

Do it: Go ahead and perform the skill.

Check: How well did my plan work?

The child uses verbal self-guidance to apply the GPDC framework to motor learning. In this approach, the therapist acts as a guide by helping the child figure out how to improve his or her motor performance on various motor skills. (36)

Like task-specific intervention, the results of initial studies of cognitive approaches are encouraging. In one study, (25) 10 children with DCD who were treated with a cognitive approach to motor development were compared with 10 children who were treated with a bottom-up approach. The children were matched for diagnoses, age, and handedness. Both groups showed improvements on various standardized motor tests after receiving 10 treatment sessions. However, children in the cognitive approach group maintained motor skill longer and generalized to nonclinical situations better than children who were treated using the bottom-up approach.

Task-specific interventions and the cognitive approach both provide repetition and practice of specific motor skills, and the cognitive approach has the added advantage of promoting independent problem solving. The greater success of top-down approaches, when compared with bottom-up approaches, (36,40) might be a result of the top-down approaches' inclusion of both spatial and motor learning sequences, combined with requirements for attention to task and working memory as the child actively engages in problem-solving activities. The results of these studies, in addition to outcome measures of the different approaches in children with DCD, would suggest that approaches that integrate systems theory (with emphasis on sensory information being only part of the picture) and motor learning theory might be most effective for these individuals. Table 2 provides a brief summary of several recent clinical trails evaluating the effectiveness of various treatment approaches used with children with DCD. (10,35,36,40-43)

The neuronal group selection theory can provide a framework for interpreting the differences in reported outcomes among the various approaches. While children with moderate to severe cerebral palsy (CP) have a limited repertoire of primary neuronal networks, which guide crude, nonspecific movements, children with DCD are believed to experience difficulty at the level of secondary variability, that is, in selecting and reinforcing the most efficient and effective pathways for a given situation. (15,44) During normal postnatal development, experience plays a primary role in the neuronal group selection process that establishes the circuitry necessary for efficient, goal-directed, and coordinated movements. (17) According to the neuronal group selection theory, this refinement of motor skill occurs during the stage of secondary variability as a combined result of trial-and-error exploration of neuronal groups, selection of specific neurons within each group, repetition of synaptic firing within and among neuronal groups, and sensory experience.

Functional synaptic connections, which act in parallel and involve cortical and subcortical (striatal and cerebellar) structures, form following exposure to a variety of motor experiences. Formation of these connections is highly dependent on sensory information. Bottom-up approaches such as sensory integration, process-oriented treatment, and perceptual motor training emphasize sensory experience, with less emphasis on cognitive processing and cortically driven motor programming. Although an intervention based entirely on information processing may provide the experience necessary to select the most effective neuronal networks, bottom-up approaches may not provide sufficient opportunity for motor practice of cognitively initiated and goal-directed tasks in order to reinforce and establish these connections. Top-down approaches focus less on the specific impairments contributing to decreased coordination and more on the gestalt of coordinated movement, that is, the dynamic interrelationships among a number of CNS structures and systems and the environment within which the task is performed.

Treatment based on a top-down approach uses task-specific interventions that provide the child the opportunity to engage in conscious problem solving, while coincident afferent input provides subcortical structures the feedback and error signals needed to identify and select the most efficient movement strategies for the task. (36) Because sensorimotor integration, internal representation of motor programs, and appropriate motor commands occur at the level of secondary variability, (15) the emphasis on sensory rather than cognitive factors by the bottom-up approaches may, in part, be responsible for the observed differences in outcomes following treatment.

A number of motor learning theories have been proposed in an attempt to explain the process through which previously learned actions are incorporated into more complex movements. (39) According to the motor control and procedural learning theory proposed by Hikosaka and colleagues, (45) motor sequence circuits that involve the basal ganglia and cerebellum become encoded following long-term practice. Once these bidirectional and parallel functioning neuronal circuits become established through practice, the child is able to incorporate previously learned sequential motor actions into yet more complex movements. Hikosaka and colleagues proposed 2 stages to such learning, the first of which relies primarily on sensory input to encode neuronal sequencing. It is during the second stage that the sequential processes necessary to accomplish the specific motor tasks become firmly established through the parallel and sequential pathways involving the basal ganglia and cerebellum. Learning new sequences in the first stage of learning requires attention and working memory. The motor sequences then become established in the late stage of learning through repetition and practice. Interventions using top-down approaches meet both of these requirements, whereas bottom-up approaches stress serial information processing only. Determining the location and nature of the neural deficiency in children with DCD is a difficult, if not impossible, task. Motor control processes are complex and depend on integrated functioning of sensory, perceptual, cognitive, and motor systems. Not only are children with DCD a heterogeneous group in terms of functional disabilities but, the specific locus of the problems observed can vary greatly from one child to the next. Because of these factors, an integrated approach to the management of children with DCD is advocated.

Conclusion

Developmental coordination disorder is a complex disorder affecting approximately 5% to 6% of school-aged children. Without intervention, these children will continue to exhibit poor motor skills and show deficits in other areas as well. Directions for future research may include determining: (1) the most appropriate level of intervention intensity, (2) which interventions produce results that generalize to the environment and provide long-term improvement in motor function, (3) what effect environmental adaptations have on the child's motor performance, and (4) whether improved motor skills lead to improved academics and, if so, the process involved that leads to the improvement.

Table 1.
Summary of Bottom-Up Versus Top-Down Approaches

Approach    Theoretical Basis             Examples

Bottom up   Focus is on remediating       Sensory integration therapy
            underlying deficits through   Process-oriented treatment
            selective transmittal of      Perceptual motor training
            sensory information, which
            the central nervous system
            interprets and organizes
            into the development of an
            appropriate movement
            strategy (10,12,34,35)

Top down    Emphasis is on cognitive or   Task-specific intervention
            problem-solving skills to     Cognitive approaches
            select and implement the        (cognitive orientation
            most appropriate strategies     to daily occupational
            for successful task             performance)
            performance (12,34,36)

Table 2.
Overview of Selected Clinical Studies Evaluating Treatment
Approaches for Children With Developmental Coordination
Disorder (DCD) (a)

Author          Design                Sample

Peters and      A-B, subjects         11 boys, 3 girls
  Wright (43)     acted as own          (age=7-8 y)
                  controls            All subjects met
                                        DSM-IV criteria
                                        for DCD

Wilson et       Pretest-posttest, 3   Blocked randomized
al (41)           groups: motor         procedure, 18
                  imagery               children (age=7-
                  training,             12 y) placed in
                  traditional           each group
                  perceptual
                  motor training,
                  no treatment

Miller et       Pretest-posttest      20 children recruited
  al (36)         group                 (14 boys, 6 girls;
                  comparison;           mean age=9.05
                  CO-OP group           y, SD = 1.23)
                  vs CTA group        Random assignment
                                        of 10 children
                                        each to CO-OP
                                        and CTA
                                        groups

Polatajko et    Three-group           Blocked random
  al (10)         randomized            assignment of 74
                  clinical trial        children (age=7-
                  with pretest,         13 y) with DCD to
                  posttest, and         1 of 3 groups:
                  follow-up             PORx, TG, no
                  testing               treatment

Sims et         Three-group           36 children matched
  al (35)         randomized            by age (6.6-10.3
                  clinical trial        y), sex, verbal IQ,
                  with pretest,         KST and TOMI
                  posttest, and         scores randomly
                  follow-up             CA, and no-
                  testing               treatment groups

Author          Measurements                 Intervention

Peters and      Pretest-posttest measures:   Once weekly for 60 min
  Wright (43)     M-ABC                        for 10 wk
                  Forced vital capacity      Group intervention
                  Perceived Competence         stressing affect,
                    Scale (children            motor, sensory, and
                    aged 8 y)                  organizational
                  Pictorial Scale of           activities
                    Perceived
                    Competence and
                    Social Acceptance
                    (children aged 7 y)

Wilson et       M-ABC given before and       Imagery training:
al (41)           after intervention           training based on
                                               software developed
                                               for project; one
                                               session lasting 60 min
                                               for 5 wk
                                             Traditional perceptual
                                               motor training:
                                               treatment of
                                               combination of gross,
                                               fine, and perceptual
                                               motor activities; one
                                               60-min session for 5
                                               wk
                                             No treatment: pretest-
                                               posttest only

Miller et       Screening tests: K-BIT,      CO-OP group: ten, 50-
  al (36)         M-ABC, VMI                   min sessions
                Identification of target     Children learned to
                  behaviors: COPM              apply GPDC strategy
                Pretest-posttest measures:     CTA group: ten, 50-
                  PQRS, VABS, BOTMP,           min sessions using a
                  SPPC                         variety of approaches
                Follow-up evaluation:          (neuromuscular,
                  Telephone interview of       multisensory,
                  parents to determine         biomechanical)
                  effectiveness to           Individual treatments
                  treatment 7.5-13 mo          provided, no group
                  following treatment          treatments

Polatajko et    Pretest-posttest measures:   PORx: kinesthetic training
  al (10)         KST, VMI, TOMI,              provided during one-
                  SCSIT                        on-one sessions lasting
                Follow-up testing also         20 min, 2-3 times a
                  performed 6 wk after         week, for a maximum
                  intervention period          of 12 sessions over 5
                  completed                    wk
                                             TG: sensory
                                               integrative, perceptual
                                               motor, and fine/gross
                                               motor activities
                                               provided in one-on-one
                                               sessions lasting 45 min
                                               for a total of 24
                                               sessions over 9 wk
                                             No treatment: no
                                               intervention provided
                                               for 11 wk

Sims et         TOMI: pretest-posttest       Both treatment groups
  al (35)       Children's checklist           received daily one-on-
                  completed by teachers        one sessions lasting 25
                  and parents at posttest      min over 2 wk
                  and 12 weeks after         No-treatment group
                  posttest                     received no treatment
                Handwriting and shape          during this time
                  copying samples from
                  children whose parents
                  or teachers had
                  completed posttest
                  checklist

Author          Results                     Comment

Peters and      Increase in improved        No control group
  Wright (43)       motor function          Detailed examples of
                  Increase in FVC             intervention techniques
                No change in competence       provided
                  scores                    Small sample size
                                            No baseline period

Wilson et       Improvement in M-ABC        Intervention periods were
al (14)           scores for both             brief; total of 5 h of
                  intervention groups,        training
                  but not in control        Did the improvements
                  group                       noted generalize to
                Rate of improvement           the children's
                  appeared to be similar      daily environment?
                  for children in the 2     Were the improvements
                  intervention groups         maintained after the
                                              intervention was
                                              complete?

Miller et       COPM: both groups           Parent rating: were
  al (36)         improved in                 parents blind to what
                  satisfaction and            group their children
                  performance                 were in?
                PQRS: CO-OP group had       Did not use a valid,
                  greater improvement         reliable measure for
                  than CTA group              long-term effect of
                VABS: CO-OP group scored      treatments
                  higher                    No control group
                BOTMP: both groups          Ten treatments provided;
                  improved                    however, frequency of
                SPPS: no change for           treatment (weekly,
                  either group                biweekly) was not
                Telephone follow-up: more     reported
                  parents (6/8) of
                  subjects in the CO-OP
                  group rated usefulness
                  of treatment high
                  compared with 2/7
                  parents of subjects in
                  the CTA group

Polatajko et    KST runway task: PORx       PORx group's improvement
  al (10)         group improved compared     on KST due to
                  with TG and no-             intervention tasks
                  treatment groups; this      similar to test tasks?
                  improvement maintained    Intervention periods not
                  at follow-up                consistent between
                KST pattern test: no          groups
                  difference between        Were the intervention
                  groups or across time       periods frequent and
                VMI: no difference            intense enough to allow
                  between groups or           for change to occur?
                  across time; post hoc
                  analysis showed a
                  difference between
                  PORx and no-treatment
                  groups at .05 level,
                  but this difference was
                  not maintained at
                  follow-up
                TOMI: no difference found
                  between groups on any
                  of the subtests
                SCSIT: no difference
                  across groups or across
                  time on kinesthesis
                  subtest; post hoc
                  analysis of Finger
                  ID subtest revealed
                  difference between TG
                  and no-treatment
                  groups at the .05
                  level; TG group scored
                  higher, but difference
                  not maintained at
                  follow-up

Sims et         TOMI: no-treatment group    Short, but intense,
  al (35)         demonstrated no change      treatment interventions
                PORx and CA groups            provided may not be
                  improved                    typical of therapy
                No difference in amount       sessions in most
                  of improvement made by      clinical settings
                  PORx and CA groups        Follow-up at 12 wk
                Children's checklist:         posttest done only for
                  only 7 adults completed     treatment groups
                  both checklists; for
                  adults who completed
                  the checklists, no
                  difference between PORx
                  and CA groups
                Handywriting sample: no
                  significant difference
                  between PORx and CA
                  groups

(a) CO-OP=cognitive approach to daily occupational performance
(cognitive approach); CTA=contemporary treatment approach
(neuromuscular, multisensory, biomechanical); PORx=process-oriented
approach; TG=traditional treatment group (sensory integration,
perceptual motor, gross and fine motor activities); VSG=verbal
self-guidance (cognitive approach); CA=cognitive affective training;
LBD=Le Bon Depart; SI=sensory integration test; K-BIT=Kaufman Brief
Intelligence Test; M-ABC=Movement Assessment Battery for Children;
COPM=Canadian Occupation Performance Measure; PQRS=Performance
Quality Rating Scale; VABS=Vineland Adaptive Behavior Scales;
BOTMP=Bruininks-Osteretsky Test of Motor Proficiency;
VMI=Developmental Test of Visual-Motor Integration, Revised;
SPPC=Self-Perception Profile for Children; TOMI=Test of Motor
Impairment; KST=Kinaesthetic Sensitivity Test; SCSIT=Southern
California Sensory Integration Test; VAS=visual analog scale;
GPDC=Goal-Plan-Do-Check; DSM-IV=Diagnostic and Statistical
Manual of Mental Disorders, 4th ed; FVC=functional vital capacity.

References

(1) Coleman R, Piek JP, Livesey DJ. A longitudinal study of motor ability and kinaesthetic acuity in young children at risk of developmental coordination disorder. Hum Mov Sci. 2001;20(1-2):95-110.

(2) Miyahara M, Register C. Perceptions of three terms to describe physical awkwardness in children. Res Dev Disabil. 2000;21:367-376.

(3) Miyahara M, Mobs I. Developmental dyspraxia and developmental coordination disorder. Neuropsychol Rev. 1995;5:245-268.

(4) Polatajko HP, Fox AM, Missiuna C. National perspective. Can J Occup Ther. 1995;1:3-6.

(5) Dewey D, Wilson BN. Developmental coordination disorder: what is it? Physical and Occupational Therapy in Pediatrics. 2001;20:5-27.

(6) Motor skills disorder 315.40: Developmental Coordination Disorder. In: Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). 4th ed. Washington, DC: American Psychiatric Association; 1994:53-55.

(7) Henderson L, Rose P, Henderson S. Reaction time and movement time in children with a Developmental Coordination Disorder. J Child Psychol Psychiatry. 1992;33:895-905.

(8) Smyth TR. Impaired motor skill (clumsiness) in otherwise normal children: a review. Child Care, Health, and Development. 1992;18:283-300.

(9) Wilson PH, McKenzie BE. Information processing deficits associated with developmental coordination disorder: a meta-analysis of research findings. J Child Psychol Psychiatry. 1998;39:829-840.

(10) Polatajko HJ, Macnab JJ, Anstett B, et al. A clinical trial of the process-oriented treatment approach for children with developmental coordination disorder. Dev Med Child Neurol. 1995;37:310-319.

(11) Wright HC, Sugden DA. A two-step procedure for the identification of children with developmental co-ordination disorder in Singapore. Dev Med Child Neurol. 1996;38:1099-1105.

(12) Sugden DA, Chambers ME. Intervention approaches and children with developmental coordination disorder. Pediatr Rehabil. 1998;2: 139-147.

(13) Waterson T. Managing the clumsy and non-reading child. Practitioner. 1999;243:675-677.

(14) Hadders-Algra M. Early brain damage and the development of motor behavior in children: clues for therapeutic intervention? Neural Plasticity. 2001;8:31-49.

(15) Hadders-Algra M. The Neuronal Group Selection Theory: a framework to explain variation in normal motor development. Dev Med Child Neurol. 2000;42:566-572.

(16) Heriza C. Motor development: traditional and contemporary theories. In: Contemporary Management of Motor Control Problems: Proceedings of the II STEP Conference. Alexandria, Va: Foundation for Physical Therapy; 1991:99-126.

(17) Edelman GM. Neural Darwinsim: selection and reentrant signaling in higher brain function. Neuron. 1993;10:115-125.

(18) Verhage M, Maia A, Plomp J, et al. Synaptic assembly of the brain in the absence of neurotransmitter secretion. Science. 2000;287:864-869.

(19) Sporns O, Edelman G. Child development, solving Bernstein's problem: a proposal for the development of coordinated movement by selection. Child Dev. 1993;64:960-981.

(20) Haddars-Algra M. Assessment of general movements: towards a better understanding of a sensitive method to evaluate brain function in young infants. Dev Med Child Neurol. 1997;35:411-421.

(21) Macnab JJ, Miller LT, Polatajko HJ. The search for subtypes of DCD: is cluster analysis the answer? Hum Mov Sci. 2001;20(1-2):49-72.

(22) Geuze RH, Jongmans MJ, Schoemaker MM, Smits-Engelsman BC. Clinical and research diagnostic criteria for developmental coordination disorder: a review and discussion. Hum Mov Sci. 2001;20(1-2): 7-47.

(23) Portney LG, Watkins MP. Foundations of Clinical Research: Applications to Practice. 2nd ed. Upper Saddle River, NJ: Prentice-Hall Health; 2000.

(24) Crawford SG, Wilson BN, Dewey D. Identifying developmental coordination disorder: consistency between tests. Physical and Occupational Therapy in Pediatrics. 2001;20:29-50.

(25) Shoemaker MM, Hijlkema MG, Kalverboer AF. Physiotherapy for clumsy children: an evaluation study. Dev Med Child Neurol. 1994;36: 143-155.

(26) Smits-Engelsman BC, Niemeijer AS, van Galen GP. Fine motor deficiencies in children diagnosed as DCD based on poor graphomotor ability. Hum Mov Sci. 2001;20(1-2):161-182.

(27) Schoemaker MM, van der Wees M, Flapper B, et al. Perceptual skills of children with developmental coordination disorder. Hum Mov Sci. 2001;20(1-2):111-133.

(28) Wilson PH, Maruff P, Ives S, Currie J. Abnormalities of motor and praxis imagery in children with DCD. Hum Mov Sci. 2001;20(1-2): 135-159.

(29) Smyth MM, Mason UC. Planning and execution of action in children with and without developmental coordination disorder. J Child Psychol Psychiatry. 1997;38:1023-1037.

(30) Skinner RA, Piek JP. Psychosocial implications of poor motor coordination in children and adolescents. Hum Mov Sci. 2001;20(1-2): 73-94.

(31) Losse A, Henderson SE, Elliman D, et al. Clumsiness in children: do they grow out of it? A 10-year follow-up study. Dev Med Child Neurol. 1991;33:55-68.

(32) Kadesjo B, Gillberg C. The comorbidity of ADHD in the general population of Swedish school-age children. J Child Psychol Psychiatry. 2001;42:487-492.

(33) Rasmussen P, Gillberg C. Natural outcome of ADHD with developmental coordination disorder at age 22 years: a controlled, longitudinal, community-based study. J Am Acad Child Adolesc Psychiatry. 2000; 39:1424-1431.

(34) Mandich AD, Polatajko HJ, Macnab JJ, Miller LT. Treatment of children with developmental coordination disorder: what is the evidence? Physical and Occupational Therapy in Pediatrics. 2001;20:51-68.

(35) Sims K, Hendersen SE, Morton J, Hulme C. The remediation of clumsiness, II: is kinaesthesis the answer? Dev Med Child Neurol. 1996;38:988-997.

(36) Miller LT, Polatajko HJ, Missiuna C, et al. A pilot trial of a cognitive treatment for children with developmental coordination disorder. Hum Mov Sci. 2001;20(1-2):183-210.

(37) Laszlo J, Bairstow P. Kinaesthesis: its measurement, training, and relationship with motor control. QJ Exp Psychol. 1983;35:411-421.

(38) Vargas S, Camilli G. A meta-analysis of research on sensory integration treatment. Am J Occup Ther. 1999;53:189-198.

(39) Mandich AD, Polatajko HJ, Missiuna C, Miller LT. Cognitive strategies and motor performance in children with developmental coordination disorder. Physical and Occupational Therapy in Pediatrics. 2001;20:125-143.

(40) Martini R, Polatajko HJ. Verbal self-guidance as a treatment approach for children with developmental coordination disorder: a systematic replication study. Occupational Therapy Journal of Research. 1998;18:157-181.

(41) Wilson PH, Thomas PR, Maruff P. Motor imagery training ameliorates motor clumsiness in children. J Child Neurol. 2002;17:491-498.

(42) Leemrijse C, Meijer OG, Vermeer A, et al. The efficacy of Le Bon Depart and Sensory Integration treatment for children with developmental coordination disorder: a randomized study with six single cases. Clin Rehabil. 2000;14:247-259.

(43) Peters JM, Wright AM. Development and evaluation of a group physical activity programme for children with developmental coordination disorder: an interdisciplinary approach. Physiotherapy Theory and Practice. 1999; 15:203-216.

(44) Hadders-Algra M, Brogren E, Katz-Salamon M, Forssberg H. Periventricular leukomalacia and preterm birth have a different detrimental effect on postural adjustments. Brain. 1999;122:727-740.

(45) Hikosaka O, Nakahara H, Rand M, et al. Parallel neural networks for learning sequential procedures. Trends Neurosci. 1999;22:464-471.

RC Barnhart, PT, MS, PCS, is Assistant Professor and Academic Coordinator of Clinical Education, Department of Physical Therapy, College of Public and Allied Health, East Tennessee State University, Johnson City, TN 37614-0624 (USA) ([e-mail]). Address all correspondence to Mr Barnhart.

MJ Davenport, PT, MS, is Assistant Professor, Department of Physical Therapy, College of Public and Allied Health, East Tennessee State University.

SB Epps, EdD, is Admission Coordinator, Department of Physical Therapy, College of Public and Allied Health, East Tennessee State University. Nordquist, PhD, is Professor, Department of Child and Family Studies, The University of Tennessee, Knoxville, Tenn.

Mr Barnhart provided concept/idea, and Mr Barnhart and Ms Davenport provided writing. Dr Epps and Dr Nordquist provided consultation (including review of manuscript before submission).