An 18-month follow-up investigation of motor coordination and working memory in primary school children

The aim of the current study was to examine the relationship between motor coordination and visual working memory in children aged 5–11 years. Participants were 18 children with movement difficulty and 41 control children, assessed at baseline and following an 18-month time period. The McCarron Assessment of Neuromuscular Development provided a measure of motor skills and the CogState One-Back task was used to assess visual working memory. Multi-level mixed effects linear regressions were used to assess the relationship between fine motor skills, gross motor skills, and visual working memory. The results revealed that for children with movement difficulty, better fine motor skills at baseline significantly predicted greater One-Back accuracy and greater (i.e., faster) speed at 18-month follow-up. Conversely, fine motor skills at baseline did not predict One-Back accuracy and speed for control children. However, for both groups, greater One-Back accuracy at baseline predicted better fine and gross motor skills at follow-up. These findings have important implications for the assessment and treatment of children referred for motor difficulties and/or working memory difficulties.     

Developmental coordination disorder and internalizing problems in children: The environmental stress hypothesis elaborated

There is a growing literature connecting poor motor coordination to physical and mental health outcomes in children and adolescents. These studies suggest that children with disorders such as developmental coordination disorder (DCD) are at greater risk for depression and anxiety, as well as obesity, and poor physical fitness. With regard to internalizing problems (symptoms of depression and anxiety), there is also evidence to suggest that the environment may play an important role in the etiology of psychological distress in this population. Cairney, Veldhuizen, & Szatmari, 2010 used the phrase “environmental stress hypothesis” to highlight the role that negative exposure to personal and interpersonal stressors might play in accounting for higher rates of internalizing symptoms in children with DCD. In this paper, we elaborate further on this basic premise, offering a model linking DCD to internalizing problems based on Pearlin’s stress process framework. In addition to stressors (risk) and protective factors, we incorporate both physical activity and obesity into our stress model. Next, we review the existing literature to see if there is evidence supporting specific components (pathways) of the model. In doing so, areas in need of further research are identified. Implications for intervention are also provided.     

The role of early fine and gross motor development on later motor and cognitive ability

The aim of this study was to determine whether information obtained from measures of motor performance taken from birth to 4 years of age predicted motor and cognitive performance of children once they reached school age. Participants included 33 children aged from 6 years to 11 years and 6 months who had been assessed at ages 4 months to 4 years using the ages and stages questionnaires (ASQ: [Squires, J. K., Potter, L., & Bricker, D. (1995). The ages and stages questionnaire users guide. Baltimore: Brookes]). These scores were used to obtain trajectory information consisting of the age of asymptote, maximum or minimum score, and the variance of ASQ scores. At school age, both motor and cognitive ability were assessed using the McCarron Assessment of Neuromuscular Development (MAND: [McCarron, L. (1997). McCarron assessment of neuromuscular development: Fine and gross motor abilities (revised ed.). Dallas, TX: Common Market Press.]), and the Wechsler Intelligence Scale for Children-Version IV (WISC-IV: [Wechsler, D. (2004). WISC-IV integrated technical and interpretive manual. San Antonio, Texas: Harcourt Assessment]). In contrast to previous research, results demonstrated that, although socio-economic status (SES) predicted fine motor performance and three of four cognitive domains at school age, gestational age was not a significant predictor of later development. This may have been due to the low-risk nature of the sample. After controlling for SES, fine motor trajectory information did not account for a significant proportion of the variance in school aged fine motor performance or cognitive performance. The ASQ gross motor trajectory set of predictors accounted for a significant proportion of the variance for cognitive performance once SES was controlled for. Further analysis showed a significant predictive relationship for gross motor trajectory information and the subtests of working memory and processing speed. These results provide evidence for detecting children at risk of developmental delays or disorders with a parent report questionnaire prior to school age. The findings also add to recent investigations into the relationship between early motor development and later cognitive function, and support the need for ongoing research into a potential etiological relationship.     

Is a quantitative approach useful in the comparison of spontaneous movements in fullterm and preterm infants?

Spontaneous motility in the first six months of infancy has been examined over the last few decades using both qualitative and quantitative techniques. The major focus of the quantitative research has been to investigate a dynamic systems approach to understanding motor development, and has primarily examined normal development in fullterm infants. Recently, there have been several papers comparing spontaneous kicking in fullterm and preterm infants. These studies were designed to identify developmental differences that may indicate a risk of later motor disability. There has, however, been criticism that the quantitative approach fails to detect developmental differences that are useful in early identification of disability, unlike qualitative approaches which use the principles of Gestalt perception to examine the quality of the total movement pattern in young infants. The current paper describes both qualitative and quantitative techniques and reviews recent studies using motion analysis to compare early motor development in fullterm and preterm infants. New evidence is provided to suggest that the quantitative approach may not only be useful in detecting infants at risk of motor disability, but may also be useful in identifying the underlying processes that determine normal and abnormal motor outcomes.     

How to Assess a Model's Testability and Identifiability

Formal definitions are given of the following intuitive concepts: (a) A model is quantitatively testable if its predictions are highly precise and narrow. (b) A model is identifiable if the values of its parameters can be ascertained from empirical observations. (c) A model is redundant if the values of some parameters can be deduced from others or if the values of some observables can be deduced from others. Various rules of thumb for nonredundant models are examined. The Counting Rule states that a model is quantitatively testable if and only if it has fewer parameters than observables. This rule can be safely applied only to identifiable models. If a model is unidentifiable, one must apply a generalization of the Counting Rule known as the Jacobian Rule. This rule states that a model is quantitatively testable if and only if the maximum rank (i.e., the number of linearly independent columns) of its Jacobian matrix (i.e., the matrix of partial derivatives of the function that maps parameter values to the predicted values of observables) is smaller than the number of observables. The Identifiability Rule states that a model is identifiable if and only if the maximum rank of its Jacobian matrix equals the number of parameters. The conclusions provided by these rules are only presumptive. To reach definitive conclusions, additional analyses must be performed. To illustrate the foregoing, the quantitative testability and identifiability of linear models and of discrete-state models are analyzed. Copyright 2000 Academic Press.