Functional performance of children with developmental coordination disorder at home and at school
ACKNOWLEDGEMENTS We gratefully acknowledge Professor Anne Henderson for her valuable comments on the manuscript, and the teachers, parents, and children who participated in this study. This study was supported through funding awarded to the corresponding author from the Department of Health, and the National Science Council, Executive Yuan, Taiwan, R.O.C. (DOH93-TD-M-113-038, DOH94-TD-M-113-007, NSC 96-2413-H-002-003).
Abstract
This study investigated the functional performance of daily activities at home and at school in a population-based sample of children with different degrees of motor coordination impairment and competence. Sixteen children (seven males, nine females; mean age 8y, SD 9mo) with developmental coordination disorder (DCD), 25 with suspected DCD ([sDCD] 17 males, eight females; mean age 7y 6mo, SD 8mo), and 63 children without motor problems (39 males, 24 females; mean age 7y 9mo, SD 7mo) were recruited from public schools (Grades 1–3, age 6y 4mo–9y 10mo) using the Chinese version of the Developmental Coordination Disorder Questionnaire, the Movement Assessment Battery for Children, and the Bruininks-Oseretsky Test of Motor Proficiency. Functional performance was assessed using the Chinese versions of the Vineland Adaptive Behavior Scales and the School Function Assessment–Chinese version. The functional performance of children with DCD and sDCD was statistically significantly lower than those without DCD (p’s<0.05). χ2 and logistic regression analyses showed significant differences among all groups in the proportion of children scoring at the ‘inadequate’ adaptive level of home performance (p’s<0.05). There were also significant differences among the groups in the proportion of children scoring below the cut-off in school performance (p’s<0.05). The findings show the pervasive impact of DCD on children’s functional performance in daily activities at home and at school.
List of Abbreviations
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- BOTMP
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- Bruininks–Oseretsky Test of Motor Proficiency
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- DCD
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- Developmental coordination disorder
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- DCDQ-C
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- Developmental Coordination Disorder Questionnaire–Chinese version
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- GOF
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- Goodness of fit
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- MABC
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- Movement Assessment Battery for Children
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- sDCD
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- Suspected developmental coordination disorder
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- SFA-C
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- School Function Assessment–Chinese version
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- VABC-C
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- Vineland Adaptive Behavior Scales–Chinese version
Successful participation in daily activities, both at home and at school, is essential for a child’s healthy and balanced development. Using the framework of the International Classification of Functioning, Disability and Health (ICF),1,2‘impairments’ in body function and structure (e.g. muscle tone and strength) are associated with significant ‘activity’ limitations (e.g. dressing, feeding, and mobility) and often lead to restricted ‘participation’ for the child (e.g. playing, participating in school activities). Many factors, both internal and external to the child, influence functional motor performance. Functional performance is defined here as both the attainment of proficiency in a wide range of activities and successful participation in activities that are socially relevant and developmentally appropriate to a child’s age, and which contribute to the ability to live a meaningful life.3
Developmental coordination disorder (DCD) is one of the most common childhood disorders,4 with prevalence ranging from 5 to 8 per cent.5,6 It has been demonstrated that children with DCD have marked impairments in motor coordination which interfere with their participation in home and academic activities,7–9 as specified in the DSM-IV-TR.5 DSM-IV-TR Criterion A stipulates that: ‘Performance in daily life activities that require motor coordination is substantially below that expected by age and IQ. This may be manifested by marked delays in achieving motor milestones, dropping things, ‘clumsiness’, and poor performance in sports or poor handwriting’. Criterion B states that ‘The disturbances in Criterion A significantly interfere with academic achievement or activities of daily living and must be measured within the context of the situation’.
Parents of children with DCD have indicated that their children experience pervasive activity restrictions at home and in school.7,8,10 Research has shown self-care functions in children with DCD to be below average for their age on items such as putting toothpaste on a toothbrush, using a hairbrush, performing self-hygiene activities, dressing, using cutlery, and tying shoelaces.3 Furthermore, it has also been observed that poor performance in activities of daily living can negatively influence physical fitness, health, self-esteem, and social adjustment.7
Academic problems for children with DCD range from poor handwriting to poor organizational skills. Motor problems, such as awkward handwriting, immature cutting ability, and poor manipulation skills, have also been documented.3,11 Case reports indicate that such children are often fatigued because they have to expend much more energy than normally developing children in paper and writing activities.11 In addition to academic limitations, physical awkwardness associated with DCD has been reported to contribute to limited participation in social and leisure activities. The literature reports that children with DCD not only participate less in physical activities at school, but also have less positive social interaction with their classmates; e.g. children with DCD spend more playground time in isolation than their peers.12,13
Enabling functional performance has long been the main goal of clinicians working with children with DCD,14 although most assessments target specific components of motor skills.15 The current study adds two dimensions to available research. First, it investigates function in the home and school and compares performance within these contexts. Second, it uses a population-based sample to compare groups of children who are typically developing or who have different degrees of motor coordination difficulties. Past research has focused on children who have been referred for coordination difficulties and who, by definition, will obviously exhibit functional limitations; several have used a qualitative approach.7,9,10 This study examined the relationship between tests of motor impairment and evidence of functional problems among children in the general population who were not identified as having DCD. It also addressed the need to evaluate comprehensively both the functional performance level of children with DCD and their level of participation in daily activities.1,16
Method
To investigate functional motor performance in a population-based group of children who had not been identified as having DCD or referred for pediatric services, the parents of approximately 2000 children completed a questionnaire to screen for motor coordination problems. The children who scored within the lowest 10th centile were considered to have difficulties; each of these children was matched by age and sex with a child scoring above the 10th centile. After standardized confirmatory motor testing, parents and teachers were asked to complete questionnaires that measured the children’s functional performance at home and at school respectively.
This study received ethical approval from the Institutional Review Board of the National Taiwan University Hospital. Parents of all participants gave written informed consent.
Sample selection
Participants were selected from six of the 141 public elementary schools of the Greater Taipei area, Taiwan, chosen from different areas to reflect a range of socio-economic status (SES). Participants were aged between 6 years 3 months and 9 years 10 months.
Letters describing the study were distributed to parents of children in Grades 1 to 3 (age 6–9y; n=1915); 1429 families agreed to participate and completed the Chinese version of the Developmental Coordination Disorder Questionnaire (DCDQ-C)17 to screen for motor competency. Children who scored below the 10th centile on the DCDQ-C (n=121) were selected for this study and received further motor testing. One hundred and twenty-one children who scored above the 10th centile on the DCDQ-C were matched for sex and age to act as a comparison group and also received further motor testing.
Instruments used to define DCD
Children with DCD form a heterogeneous group, and different assessments of impairment may define problems differently. Crawford et al2 found that the two most popular tests for identifying DCD, the Movement Assessment Battery for Children (MABC)6 and the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP),18 do not necessarily give identical results in diagnosing children with DCD. They postulate that underlying factors such as attention, memory, or visuomotor demands influence the measurement of motor performance and affect test outcomes. As a given test may not differentiate children accurately, the use of more than one test to identify children with DCD has been proposed. The two-step procedure uses first a questionnaire which screens for the condition and then standardized motor tests to confirm the diagnosis.19
Children were diagnosed with DCD if they scored equal to or lower than the 10th centile of the DCDQ-C20 and also scored in the ‘deficient’ range on one of the four motor measures. These were, at or below the 5th centile on the MABC,6 or at or below the 4th centile on the BOTMP Fine Motor Composite (FM), the BOTMP Gross Motor Composite (GM), or the BOTMP Battery Composite (BC).18 Children were classified as ‘suspected’ DCD (sDCD) if they scored lower than the 25th centile of the DCDQ-C and also scored in the suspect range on one of the four motor measures, i.e. between the 6th and 15th centiles on the MABC,6 or between the 5th and 22nd centiles on the BOTMP-FM Composite, the BOTMP-GM Composite, or the BOTMP-BC.18 Children who scored above the 25th centile on the DCDQ-C and had all four motor scores within the normal range were placed in the comparison group.
Functional performance measures
Vineland Adaptive Behavior Scale–Chinese version (VABS-C)
The VABS-C21 is a questionnaire administered to the caregivers of children aged 0 to 18 years. It is one of the few assessment measures that include functional tasks and participation within the ICF framework.1,15 It assesses the child’s proficiency in performing various daily activities in social, daily living, communication, and motor domains. Only the Personal Living Skill subscale of the Daily Living Skill domain and the Gross Motor and Fine Motor subscales in the Motor Skill domain were used in this study. The Personal Living Skill subscale contains six categories which are: eating and drinking, toileting, grooming, appearance, health care, and dressing. The Gross Motor subscale consists of walking, running, and play activities, and the Fine Motor subscale includes manipulation, painting, and using scissors. Test–retest reliability of the VABS-C has been reported to be between 0.62 and 0.95, and interrater reliability between 0.74 and 0.89. Split-half reliability of each subscale of the VABS-C ranged from 0.64 to 0.87.
The five adaptive levels of each subscale of the VABS-C are: very low, low, median, high, and very high. However, the range of levels is different with different ages. For example, on the Personal Living Skill subscale, there are five levels for 6-year-olds, four levels for 7-year-olds, and three levels for 9-year-olds. As children in different age groups had different ranges of adaptive levels, we grouped five levels into two categories: adequate (including levels of median, high, and very high) and inadequate (including levels of very low and low).
School Function Assessment–Chinese version (SFA-C)
The SFA-C,22 translated from the SFA,23 is a questionnaire that rates children’s functional performance on school-related activities as compared with their peers, and is frequently used for individual education plans for children with special needs. It consists of three parts, Participation, Task supports, and Activity Performance. In this study, nine subscales of the Physical Task section of Activity Performance were used. Internal consistency of the nine subscales ranged from 0.95 to 0.98 and test–retest coefficients of the nine subscales ranged from 0.87 to 0.98, demonstrating reliability for the Chinese version.22
Because the aim of the study was to investigate the performance of children with DCD in motor-related activities, only the subscales related to motor function were used.
Participants
Initially, 121 children were identified as possibly having DCD; an equal number of children without coordination problems were matched by age and sex. These 242 children had confirmatory motor testing and, based on the two-step assessment procedure outlined above, only 104 clearly met the criterion for having DCD, sDCD, or being typically developing. Sixteen children were identified as having DCD, 25 sDCD, and 63 children served as a comparison group.
All three groups (DCD, sDCD, and comparison) had average or above average intelligence as assessed by the Coloured Progressive Matrices–Chinese version.24 The participants were primarily from middle-class socio-economic backgrounds, based on occupation and education as assessed by the Hollingshead Two Factor Index of Social Position.25 In two-parent families with both parents residing in the same home, the higher social position was used. Table I shows the group differences in demographic characteristics and functional performance at home and at school among the three groups.
| DCD | sDCD | Comparison | χ 2 | F | p | |
|---|---|---|---|---|---|---|
| Age, mean (SD), y:mo | 8:0 (0:9) | 7:6 (0:10) | 7:10 (0:9) | – | 2.26 | 0.11 |
| Sex | ||||||
| M/F (n) | 7/9 | 17/8 | 39/24 | 2.52 | – | 0.28 |
| Mean SES | 3 | 2.68 | 2.83 | – | 8.99 | 0.17 |
| VABS-C, mean (SD) | ||||||
| Personal Living Skill | 61.3 (7.8) | 57.3 (12.7) | 66.1 (4.4) | – | 11.23 | <0.05 |
| Gross Motor | 25.6 (2.9) | 28.2 (3.8) | 29.2 (4.3) | – | 15.50 | <0.05 |
| Fine Motor | 22.2 (2.7) | 23.3 (2.6) | 24.5 (4.6) | – | 23.00 | <0.05 |
| SFA-C, mean (SD) | ||||||
| Travel | 87.3 (14.0) | 89.6 (14.0) | 94.7 (9.5) | – | 3.27 | 0.04 |
| MCP | 83.1 (15.2) | 88.7 (16.3) | 94.1 (10.3) | – | 5.43 | <0.05 |
| Recreational Movement | 67.8 (16.7) | 75.6 (20.4) | 88.4 (15.6) | – | 10.52 | <0.05 |
| MM | 90.1 (12.3) | 88.3 (14.7) | 95.0 (8.9) | – | 3.73 | 0.03 |
| Using Materials | 82.4 (14.6) | 85.1 (15.5) | 92.6 (10.9) | – | 5.47 | <0.05 |
| Setup and Cleanup | 87.5 (11.0) | 86.1 (14.1) | 92.3 (10.5) | – | 2.94 | 0.05 |
| Eating and Drinking | 90.5 (12.5) | 86.2 (11.8) | 95.2 (9.4) | – | 8.31 | <0.05 |
| Up-Down Stairs | 86.4 (18.5) | 90.7 (18.3) | 96.4 (11.5) | – | 3.31 | 0.04 |
| Written Work | 81.2 (16.4) | 83.9 (16.2) | 91.4 (11.8) | – | 4.75 | 0.01 |
- DCD, developmental coordination disorder; sDCD, suspected developmental coordination disorder; SES, socio-economic status; VABS-C, Vineland Adaptive Behavior Scales–Chinese version; SFA-C, School Function Assessment–Chinese version; MCP, Maintaining and Changing Positions; MM, Manipulation with Movement.
Procedure
Parents were asked to fill out the Personal Living Skill subscale and the Gross and Fine Motor subscales of the Motor Skill domain of the VABS-C, and classroom teachers were asked to fill out nine subscales of the SFA-C.
Statistical analysis
Both parametric and non-parametric methods were used in analysis. Multiple linear regression models were fitted to find the covariates significantly associated with functional performance at home and at school. Independent variables considered in the stepwise variable selection procedure included age, sex, SES, and group (DCD, sDCD and comparison group). The dependent variables were three subscales of the VABS-C and the nine subscales of the SFA-C.
Group differences in the adaptive levels of the VABS-C and cut-off levels of the SFA-C were examined using χ2 analyses. Furthermore, multiple logistic regression analyses were conducted to find the covariates associated with the adaptive levels of the VABS-C and cut-off levels of the SFA-C.
The goal of regression analysis is to obtain a parsimonious regression model that fits the observed data well. To ensure the quality of the results, the basic model-fitting techniques for (1) variable selection, (2) goodness-of-fit (GOF) assessment, and (3) regression diagnostics were used in the regression analyses. Specifically, in stepwise variable selection procedure, all the significant and non-significant covariates were considered and both the significance levels for entry (SLE) and for stay (SLS) were set to 0.15 or higher. The GOF measures, including coefficients of determination of R2 (for linear regression model) and Nagelkerke R2 (for logistic regression model), and the Hosmer-Lemeshow GOF test (for logistic regression model) were examined to assess the GOF of the fitted regression models, although the value of Nagelkerke R2 is usually low for binary response. Statistical methods for regression diagnostics, such as residual analysis, detection of influential cases, and check for multicollinearity, were applied to examine problems within the model or the data. In statistical testing, two-sided p≤0.05 was considered statistically significant. Assuming that all missing data occurred at random, the observations with missing data were excluded from the analyses.
Results
Functional performance at home
As shown in Table II, the fitted multiple linear regression models showed that, when the effects of age, sex, and SES were controlled, the DCD and sDCD groups scored significantly lower than the comparison group on the mean scores of all three subscales (p's<0.05), i.e. Personal Living Skill, Gross Motor, and Fine Motor subscales. However, the statistically significant difference between the DCD and sDCD groups was noted only in the Gross Motor subscale (p=0.02). The value of R2 ranged from 0.51 to 0.59, indicating that the predictors in the fitted final linear regression models could explain more than 50% of the variance in functional performance at home.
| Intercept | DCD vs Comparison | sDCD vs Comparison | DCD vs sDCD | Age | Sex | SES | Nagelkerke R2 | |
|---|---|---|---|---|---|---|---|---|
| VABS-C | ||||||||
| PersonalLiving Skill | 68.10 | –5.20b | –9.59a | – | – | –3.36b | – | 0.51 |
| Gross Motor | 29.64 | –4.04a | –1.94a | –2.10b | – | – | – | 0.52 |
| Fine Motor | 25.35 | –3.15a | –2.31a | – | – | – | – | 0.59 |
| SFA-C | ||||||||
| Travel | 96.78 | –7.10b | – | – | – | –5.58b | – | 0.29 |
| MCP | 94.46 | –11.39a | –5.78c | – | – | – | – | 0.32 |
| Recreational Movement | 49.69 | –21.14a | –12.15a | –8.99d | 4.86b | – | – | 0.48 |
| MM | 95.12 | –4.98 | –6.84b | – | – | – | – | 0.27 |
| Using Materials | 92.69 | –10.33a | –7.57b | – | – | – | – | 0.32 |
| Setup and Cleanup | 92.41 | –4.91 | – 6.29b | – | – | – | – | 0.24 |
| Eating and Drinking | 95.97 | –5.47 | –9.81a | – | – | – | – | 0.39 |
| Up-Down Stairs | 64.49 | –10.72b | – | – | 4.44 b | –7.48b | – | 0.36 |
| Written Work | 95.94 | –11.76a | –7.32b | – | – | –6.90b | – | 0.38 |
- a p≤0.01 (two-tailed). bp≤0.05 (two-tailed). cp=0.056. dp = 0.09. DCD, developmental coordination disorder; sDCD, suspected developmental coordination disorder; SES, socio-economic status; VABS-C, Vineland Adaptive Behavior Scales–Chinese version; SFA-C, School Function Assessment–Chinese version; MCP, Maintaining and Changing Positions; MM, Manipulation with Movement.
In Figure S1 (supporting information published online), the proportion of children who scored in the inadequate level on the VABS-C was compared among the DCD, sDCD, and comparison groups. χ2 analysis yielded significant differences within the three groups for all three subscales (x2=11.28 – 28.01, p’s<0.05). Moreover, as shown in Table III, multiple logistic regression analyses revealed that after adjusting for the effects of age, sex, and SES, both the DCD and the sDCD groups had significantly higher proportions of children who scored in the inadequate level compared with the comparison group. However, a statistically significant difference between the DCD and sDCD groups was only noted in the Gross Motor subscale. The value of Nagelkerke R2 ranged from 0.15 to 0.53, indicating that the GOF of the logistic regression models was fair to good, although the value of this GOF measure is usually low for binary response.
| Intercept | DCD vs Comparison | sDCD vs Comparison | DCD vs sDCD | Age | Sex | SES | Nagelkerke R2 | |
|---|---|---|---|---|---|---|---|---|
| VABS-C | ||||||||
| PLS | –1.79 | 1.55b | 1.39a | – | – | – | – | 0.15 |
| Gross Motor | –2.71 | 3.27a | 1.70a | 1.5b | – | – | – | 0.35 |
| Fine Motor | 10.70 | 3.68a | 3.54a | – | –1.8a | 1.85c | – | 0.53 |
| SFA-C | ||||||||
| Travel | –1.18 | 1.64b | – | – | – | 0.97b | – | 0.13 |
| MCP | –7.03 | 2.23a | – | 2.2a | 0.77b | 1.44b | – | 0.24 |
| Recreational Movement | –2.34 | 2.14b | 1.46b | – | – | – | – | 0.21 |
| MM | –0.58 | 0.98 | 1.16b | – | – | – | – | 0.08 |
| Using Materials | –0.82 | 1.40b | 1.41b | – | – | – | – | 0.12 |
| Setup and Cleanup | –0.98 | 1.08 | 1.27b | – | – | – | – | 0.10 |
| Eating and Drinking | –0.70 | 1.11 | 1.29b | – | – | – | – | 0.10 |
| Up-Down Stairs | –6.06 | 2.13a | – | 2.1a | 0.75b | – | – | 0.19 |
| Written Work | –1.26 | 1.83a | 1.26b | – | – | – | – | 0.14 |
- a p≤0.01 (two-tailed). bp≤0.05 (two-tailed). cp=0.054. DCD, developmental coordination disorder; sDCD, suspected developmental coordination disorder; SES, socio-economic status; VABS-C, Vineland Adaptive Behavior Scales–Chinese version; PLS, Personal Living Skill; SFA-C, School Functioning Assessment–Chinese version; MCP, Maintaining and Changing Positions; MM, Manipulation with Movement.
Functional performance at school
As shown in Table II, after accounting for the effects of age, sex, and SES, the DCD group scored lower than the comparison group on six subscales of the SFA-C (p's<0.05). Significant differences were not seen in the Manipulation with Movement, Setup and Cleanup, or Eating and Drinking subscales. In contrast, the children with sDCD scored below the comparison group on seven subscales of the SFA-C (p's<0.05), but not on the Travel and the Up-Down Stairs subscales. The DCD group attained lower scores than the sDCD group on the Recreational Movement subscale, although the difference was not significant (p=0.09). The value of R2 ranged from 0.24 to 0.48, indicating that 24 to 48 per cent of the variance of functional performance at school could be explained by the predictors in the fitted final linear regression models.
The cut-off score of the SFA-C served as a supplementary index of difficulty; if a score falls below the cut-off score, it implies that the child is functionally behind his or her peers in a school task/activity and may need more assistance in performing school-related tasks than typical children in the same grade. Group differences on the proportion of children whose performances were below the cut-off score were examined using χ2 analysis and multiple logistic regression analysis. The proportion of children who scored below the cut-off score on the subscales was compared among the DCD, sDCD, and comparison groups (see Fig. S2, supporting information published online). χ2 analysis showed significant differences among these three groups on seven subscales (x2=6.55–15.57, p's<0.05); differences approached significance in the Manipulation with Movement (p=0.06) and the Setup and Cleanup (p=0.08) subscales. Moreover, as shown in Table III, logistic regression analyses revealed that adjusting for the effects of age, sex, and SES, the DCD group had a significantly larger proportion of children who scored below the cut-off score than the comparison group on six subscales, but not on the Manipulation with Movement, Setup and Cleanup, and Eating and Drinking subscales. In contrast, the sDCD group had a significantly higher proportion of children who scored below the cut-off score on six subscales, compared with the comparison group (p's<0.05), but not on the Travel, Maintaining and Changing Positions, and Up-Down Stairs subscales. However, the DCD group scored significantly lower than the sDCD group only on the Maintaining and Changing Positions (p<0.01) and Up-Down Stairs (p<0.05) subscales. The value of Nagelkerke R2 ranged from 0.08 to 0.24, indicating that the GOF of the fitted logistic regression models was poor to fair, although the value of this GOF measure is usually low for binary response.
Correlations between functional performance at home and at school in children with DCD and sDCD
Functional performance at home was measured by three subscales of the VABS-C, whereas functional performance at school was measured by nine subscales of the SFA-C. Correlations between performances at home and school for DCD and sDCD groups were analysed by computing Pearson’s correlation coefficients. As shown in Table IV, none of the subscales of the VAB-C was significantly correlated with any of the subscales of the SFA-C (r=–0.17 to 0.31, all p's>0.05).
| SFA-C | VABS-C | ||
|---|---|---|---|
| Personal Living Skill | Gross Motor | Fine Motor | |
| Travel | 0.197 | 0.227 | 0.068 |
| Maintaining and Changing Positions | 0.182 | 0.198 | −0.061 |
| Recreational Movement | 0.026 | 0.140 | 0.033 |
| Manipulation with Movement | 0.284 | 0.147 | 0.046 |
| Using Materials | 0.232 | 0.083 | −0.178 |
| Setup and Cleanup | 0.309 | 0.134 | −0.060 |
| Eating and Drinking | 0.007 | −0.011 | −0.108 |
| Up-Down Stairs | 0.085 | 0.116 | −0.079 |
| Written Work | 0.276 | −0.089 | −0.075 |
- All p values > 0.05. DCD, developmental coordination disorder; sDCD, suspected developmental coordination disorder; VABS-C, Vineland Adaptive Behavior Scales, Chinese version; SFA-C, School Functioning Assessment–Chinese version.
Discussion
This study examined functional performance both at home and school, of typically developing children and children with motor coordination problems. Results of this study confirmed that the performance of a population-based sample of children with motor coordination problems, who had not been identified by parents or professionals as exhibiting functional limitations, was significantly poorer than that of typically developing children. A pervasive difficulty in the motor activities of children with DCD and sDCD is clearly shown by the high percentages demonstrating inadequate performance and confirms prior anecdotal evidence26 and both qualitative7,10 and quantitative8,27 research findings. Rodgers et al. found that 4 to 7-year-old children with DCD scored 1SD below the mean on the Self-care subscale of the Pediatric Evaluation of Disability Inventory.3 The study reported here targeted an older group (6–9y) and found that non-referred children with either DCD or sDCD had comparable difficulties in the area of the self-care skills, as measured by the VABS-C. A closer analysis of the scores revealed that these children had low scores, not only for skillful strategies such as grooming, manipulating, and play activities, but also for basic skills such as dressing. However, the Manipulation with Movement, Setup and Cleanup, and Eating and Drinking subscales of the SFA-C did not show significant differences between the DCD and the comparison groups in both linear and logistic regression analyses. These results might be due to the relatively small sample size in the DCD group (n=16).
This study adds further knowledge to past research and shows that non-referred children with DCD have difficulties in most activities that support the mastery of educational activities, such as using materials and changing position, as well as in academic performance itself.11 Particular problems in Recreational Movement were discovered, a finding consistent with previous studies which have reported that children with movement difficulties play less and often withdraw from participation in physical activities, games, and sports.12,13 Referrals of children with DCD are usually related to academic problems,27 but it is clear that difficulties in movement associated with leisure and active living also warrant attention.
As Criterion B of the DSM-IV-TR5 implies, school performance and activities of daily living are two distinct contexts and most researchers have studied them separately.3 In this study, no significant correlation was found between functional performance at home and at school in children with motor coordination problems. This finding supports clinical and research impressions that children’s motor performance is not always consistent in different contexts, especially when there are differences in time pressures between home and school. In addition, perceptions of parents as primary caregivers may be quite different from the judgment of teachers, who may value independence more than direct care. Studies comparing parent and teacher reports have found moderate levels of agreement of 0.3828 and 0.59.29 Finally, children with DCD are a heterogeneous group, and those who have poor functional performance at home may not necessarily experience limitations at school, or vice versa.
In this study, children with DCD had more difficulties than those with sDCD only on the Gross Motor subscale of the VABS-C. The items in the Gross Motor subscale are mainly related to walking, running, and playing activities. In a similar vein, children with DCD performed similarly to those with sDCD on all subscales of the SFA-C except in the Recreational Movement subscale. These findings imply that the play-related activities might better differentiate children with differing severity of motor coordination.
The DCD group had a larger proportion of children who scored below the cut-off score than the sDCD group only on the school-related Maintaining and Changing Positions and Up-Down Stairs subscales; this could be related to the simplicity of the tasks of these two subscales which resulted in the performance of the sDCD group being close to that of the comparison group.
Furthermore, our results showed that children with motor disabilities had a significantly higher risk of functional performance both at home and at school, regardless of the degree of severity. This result echoed Dewey et al.’s finding 30 that children with DCD and sDCD, regardless of the degree of severity, were at risk of problems in attention, learning, and psychosocial adjustment.
Clinical implications
This study investigated the performance of children with motor coordination problems who had not been identified or referred for pediatric services. In contrast to most studies, which used clinical samples of referred children, this study used a population-based community sample to avoid potential bias resulting from high comorbidity with other diagnoses. Hence, this sample could be considered representative of typically developing children. Standardized tests showed that children with DCD and sDCD performed more poorly than the comparison group on most of the measures of functional performance at home and at school. This study also highlighted the cross-cultural nature of this developmental condition as it occurs in and has an impact on children across ethnicities and cultures.
The diagnostic criterion of DCD provided by the DSM-IV-TR does not specify how many and which of the daily activities a child should fail in to be diagnosed with DCD. This study contributes to the knowledge of DCD by providing evidence that it may affect daily living activities in both school and home contexts. As there is no strong relationship between scores obtained from parents for home activities or from teachers for school performance, the importance of assessing children across several contexts and triangulating information is highlighted. Furthermore, it was found that children with different degrees of motor coordination problems tended to have similar degrees of limitations in their functional performance in daily living activities.
Adaptive behavior refers to the quality of everyday performance in coping with environmental demands and the effectiveness of or the degree to which the individuals meets the standards of daily living skills expected of their age group.31 The low to very low adaptive levels on the VABS-C and the proportion scoring below the cut-off on the SFA-C indicate that many children with DCD or sDCD are not coping well with environmental demands. This clear picture of the adaptive behavior of children alerts clinicians of the need to identify DCD when functional problems are described by parents or teachers, and employ appropriate intervention strategies.
Limitations of the study
The sample size of this study and the ages included were relatively small. In particular, the DCD group had a relatively small sample size (n=16). As a general rule of thumb, sample size of 100 is a minimum requirement for regression analysis, but 300 is preferred. Future studies may recruit more children with a wider age range, from rural and suburban areas, to verify the findings of this paper.
Conclusions
This study found that DCD has a pervasive impact on children’s function at home and in school, and that the children with motor coordination problems tended to encounter the difficulty in daily and academic life. In the light of these findings, it is suggested that parents, teachers, and clinicians should be aware of the need to identify deficits in functional performance and plan for appropriate intervention.
