Hilde Van Waelvelde

Hippocampal contribution to early and later stages of implicit motor sequence learning

Implicit motor sequence learning refers to an important human ability to acquire new motor skills through the repeated performance of a motor sequence. This learning process is characterized by slow, incremental gains of motor performance. The present fMRI study was developed to better delineate the areas supporting these temporal dynamics of learning. By using the serial color matching paradigm, our study focused on the motor level of sequence learning and tracked the time course of learning-related neural changes. Imaging results showed a significant contribution of the left anterior hippocampus in an early sequence acquisition stage (first scanning session) as well as during a later stage with stabilized learning effects (second scanning session). Hippocampal activation significantly correlated with the behavioral learning process and was affected by a change of the motor sequence. These results suggest a strong involvement of the hippocampus in implicit motor sequence learning. On the other hand, a very extensive and bilateral neural network of parietal, temporal and frontal cortical areas (including SMA, pre-SMA) together with parts of the cerebellum and striatum were found to play a role during random visuo-motor task performance.

Association between visual perceptual deficits and motor deficits in children with developmental coordination disorder

This study explored the relation between a motor-free visual perceptual deficit, different visual-motor integration deficits, and different motor skills in children with developmental coordination disorder (DCD). Thirty-six children (22 males), aged 9 or 10 years, with DCD and a control group (n=36), matched for age and sex, were assessed with the Movement Assessment Battery for Children (MABC), a ball-catching test, a jumping test, a timed response task to a visual moving stimulus, and the Beery-Buktenica Developmental Test of Visual-Motor Integration, incorporating copying, visual discrimination, and tracing tasks. Children with DCD performed significantly worse than the control group on all measures. The visual discrimination task did not correlate significantly with any of the motor tasks. The visual timing task correlated significantly with the ball-catching test in the DCD group. The copying test was significantly correlated with the MABC in the DCD group. The association between visual-perceptual deficits and motor tasks was shown to be task specific.

Impaired visuo-motor sequence learning in Developmental Coordination Disorder

The defining feature of Developmental Coordination Disorder (DCD) is the marked impairment in the development of motor coordination (DSM-IV-TR, American Psychiatric Association, 2000). In the current study, we focused on one core aspect of motor coordination: learning to correctly sequence movements. We investigated the procedural, visuo-motor sequence learning abilities of 18 children with DCD and 20 matched typically developing (TD) children, by means of the serial reaction time (SRT) task. Reaction time measurements yielded two important findings. Overall, DCD children demonstrated general learning of visuo-motor task demands comparable to that of TD children but failed to learn the visuo-motor sequence. Interestingly, a sequence recall test, administered after the SRT task, indicated some awareness of the repeating sequence pattern. This suggests that the sequence learning problems of DCD children might be located at the stage of motor planning rather than sequence acquisition.

Stability of motor problems in young children with or at risk of autism spectrum disorders, ADHD, and or developmental coordination disorder

Aim  The aim of this study was to investigate the stability of motor problems in a clinically referred sample of children with, or at risk of, autism spectrum disorders (ASDs), attention‐deficit–hyperactivity disorder (ADHD), and/or developmental coordination disorder (DCD).

Is the Movement Assessment Battery for Children-2nd edition a reliable instrument to measure motor performance in 3 year old children?

Formal testing of 3 year old children is a new feature in the revised version of the Movement Assessment Battery for Children (Movement ABC-2). Our study evaluated the reliability and explored the clinical applicability of the Movement ABC-2 Test in this young age group. A total of 50 typically children were given two trials of the test within a one to two week interval by two physical therapists: same assessor (n=28 children) and different assessors (n=22 children). Psychometric properties were evaluated by calculating internal consistency (Cronbach α), intra-class correlation (ICC), the standard error of measurement (SEM), the smallest detectable difference (SDD) and Kappa values for classification agreement. The results are promising for future implementation of the Movement ABC-2 in clinical practice. The childrens performance was highly reproducible when tested by the same assessor (ICC .94) The SEM was 1.7 or 2.1 standard scores for 90% or 95% confidence intervals respectively, making the test sensitive enough to detect individual changes. If two different assessors tested the children the ICC was .76. In conclusion, the revised test can be applied to assess motor performance in typically developing 3-year old children. Future studies are needed to confirm if the same can be said for children with motor delays.

The Neural Basis of Implicit Perceptual Sequence Learning

The present fMRI study investigated the neural areas involved in implicit perceptual sequence learning. To obtain more insight in the functional contributions of the brain areas, we tracked both the behavioral and neural time course of the learning process, using a perceptual serial color matching task. Next, to investigate whether the neural time course was specific for perceptual information, imaging results were compared to the results of implicit motor sequence learning, previously investigated using an identical serial color matching task (Gheysen et al., 2010). Results indicated that implicit sequences can be acquired by at least two neural systems: the caudate nucleus and the hippocampus, having different operating principles. The caudate nucleus contributed to the implicit sequence learning process for perceptual as well as motor information in a similar and gradual way. The hippocampus, on the other hand, was engaged in a much faster learning process which was more pronounced for the motor compared to the perceptual task. Interestingly, the perceptual and motor learning process occurred on a comparable implicit level, suggesting that consciousness is not the main determinant factor dissociating the hippocampal from the caudate learning system. This study is not only the first to successfully and unambiguously compare brain activation between perceptual and motor levels of implicit sequence learning, it also provides new insights into the specific hippocampal and caudate learning function.

Construct Validity of the Assessment of Balance in Children Who Are Developing Typically and in Children With Hearing Impairments

Background Children with hearing impairments have a higher risk for deficits in balance and gross motor skills compared with children who are developing typically. As balance is a fundamental ability for the motor development of children, a valid and reliable assessment to identify weaknesses in balance is crucial. Objective The purpose of this study was to investigate the construct validity of posturography and clinical balance tests in children with hearing impairments and in children who are developing typically. Methods The study involved 53 children with typical development and 23 children with hearing impairments who were between 6 and 12 years of age and without neuromotor or orthopedic disorders. All participants completed 3 posturography tests (modified Clinical Test of Sensory Interaction of Balance [mCTSIB], unilateral stance, and tandem stance) and 4 clinical balance tests (one-leg stance with eyes open and with eyes closed, balance beam walking, and one-leg hopping). Results Three conditions of the mCTSIB, unilateral stance, and 2 clinical balance tests were able to distinguish significantly between the 2 groups. Children with hearing impairments showed more difficulties in balance tasks compared with children who were developing typically when 1 or 2 types of sensory information were eliminated or disturbed. The study showed only low to moderate correlations among the different methods of evaluating balance. Conclusions Clinical balance tests and posturography offer different but complementary information. An assessment protocol for balance consisting of posturography and clinical balance tasks is proposed. Static and dynamic balance abilities could not be differentiated and seem not to be a valid dichotomy.

SOS : a screening instrument to identify children with handwriting impairments

ABSTRACT Poor handwriting has been shown to be associated with developmental disorders such as Developmental Coordination Disorder, Attention Deficit Hyperactivity Disorder, autism, and learning disorders. Handwriting difficulties could lead to academic underachievement and poor self-esteem. Therapeutic intervention has been shown to be effective in treating children with poor handwriting, making early identification critical. The SOS test (Systematic Screening for Handwriting Difficulties) has been developed for this purpose. A child copies a sample of writing within 5 min. Handwriting quality is evaluated using six criteria and writing speed is measured. The Dutch SOS test was administered to 860 Flemish children (7–12 years). Inter- and intrarater reliability was excellent. Test–retest reliability was moderate. A correlation coefficient of 0.70 between SOS and “Concise Assessment Methods of Children Handwriting” test (Dutch version) confirmed convergent validity. The SOS allowed discrimination between typically developing children and children in special education, males and females, and different age groups.

Mathematical Problems in Children with Developmental Coordination Disorder.

Developmental coordination disorder (DCD) is a heterogeneous disorder, which is often co-morbid with learning disabilities. However, mathematical problems have rarely been studied in DCD. The aim of this study was to investigate the mathematical problems in children with various degrees of motor problems. Specifically, this study explored if the development of mathematical skills in children with DCD is delayed or deficient. Children with DCD performed significantly worse for number fact retrieval and procedural calculation in comparison with age-matched control children. Moreover, children with mild DCD differed significantly from children with severe DCD on both number fact retrieval and procedural calculation. In addition, we found a developmental delay of 1 year for number fact retrieval in children with mild DCD and a developmental delay of 2 years in children with severe DCD. No evidence for a mathematical deficit was found. Diagnostic implications are discussed.

Identifying Subtypes Among Children With Developmental Coordination Disorder and Mathematical Learning Disabilities, Using Model-Based Clustering

A relationship between motor and mathematical skills has been shown by previous research. However, the question of whether subtypes can be differentiated within developmental coordination disorder (DCD) and/or mathematical learning disability (MLD) remains unresolved. In a sample of children with and without DCD and/or MLD, a data-driven model-based clustering was used to identify subgroups of individuals with relatively homogeneous profiles on measures associated with motor and mathematical skills. One subgroup of children with motor problems was found based on motor variables. Based on mathematical variables, two clinical clusters were found: a subtype with number fact retrieval problems and a subtype with procedural calculation problems. Clustering with motor and mathematical skills revealed two clinical clusters: a cluster with number fact retrieval as well as procedural calculation problems and below average motor and visual-motor integration skills. A second cluster of children had only procedural calculation and visual-motor problems. Our results raise questions about the usefulness of placing children who have below average mathematical skills into a single diagnostic category. Furthermore, we inform ongoing debates about the overlap between DCD and MLD, as below average motor skills were found in both MLD subgroups, although a different motor profile is linked to a different mathematical profile.