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Maëlle Biotteau,1 Jérémy Danna,2 Éloïse Baudou,3 Frédéric Puyjarinet,4 Jean-Luc Velay,2 Jean-Michel Albaret,1,5 Yves Chaix1,31ToNIC, Toulouse NeuroImaging Center, University of Toulouse, Inserm, UPS, Toulouse, France; 2Cognitive Neurosciences Laboratory, CNRS-Aix Marseille University, Marseille, France; 3Pediatric Neurology Unit, Children’s Hospital, Purpan University Hospital, Toulouse, France; 4EuroMov Laboratory, University of Montpellier, Montpellier, France; 5Psychomotor Training Institute, University of Toulouse Paul Sabatier, Toulouse, FranceAbstract: Developmental coordination disorder (DCD) is a common and well-recognized neurodevelopmental disorder affecting approximately 5 in every 100 individuals worldwide. It has long been included in standard national and international classifications of disorders (especially the Diagnostic and Statistical Manual of Mental Disorders). Children and adults with DCD may come to medical or paramedical attention because of poor motor skills, poor motor coordination, and/or impaired procedural learning affecting activities of daily living. Studies show DCD persistence of 30–70% in adulthood for individuals who were diagnosed with DCD as children, with direct consequences in the academic realm and even beyond. In particular, individuals with DCD are at increased risk of impaired handwriting skills. Medium-term and long-term prognosis depends on the timing of the diagnosis, (possible) comorbid disorders (and their diagnosis), the variability of signs and symptoms (number and intensity), and the nature and frequency of the interventions individuals receive. We therefore chose to investigate the signs and symptoms, diagnosis, and rehabilitation of both DCD and developmental dysgraphia, which continues to receive far too little attention in its own right from researchers and clinicians.Keywords: developmental coordination disorder, developmental dysgraphia, clinical expressions, diagnosis, therapy, assessment tools

This study investigates how motor coordination undergoes the passage from a discrete to a continuous movement régime. Participants repeated concatenated discrete movements with each hand such that one hand was lagging the other by a quarter of a cycle (i.e., with a 90° phase difference). As movement frequency increased, the tendency to persist in this relative phase competed with a progressive effect of the interlimb coupling favoring 0° and 180°. In 61% of the participants, a switch from a discrete to a continuous motion régime was accompanied by a shift toward the 0° or 180°. The 0° was more often favored than 180°. The remaining participants sustained a relative phase close to 90° even at the highest movement frequency and proved to be more accurate at the initial lowest frequency. These findings indicate that a priming effect may circumvent the tendency to produce preferred patterns and favor the production of nonpreferred patterns and that initial individual differences affect how motor coordination evolves with changing constraints. [ABSTRACT FROM AUTHOR]

Procedural learning has been mainly tested through motor sequence learning tasks in children with neurodevelopmental disorders, especially with isolated Developmental Coordination Disorder (DCD) and Reading Disorder (RD). Studies on motor adaptation are scarcer and more controversial. This study aimed to compare the performance of children with isolated and associated DCD and RD in a graphomotor adaptation task. In total, 23 children with RD, 16 children with DCD, 19 children with DCD-RD, and 21 typically developing (TD) children wrote trigrams both in the conventional (from left to right) and opposite (from right to left) writing directions. The results show that movement speed and accuracy were more impacted by the adaptation condition (opposite writing direction) in children with neurodevelopmental disorders than TD children. Our results also reveal that children with RD have less difficulty adapting their movement than children with DCD. Children with DCD-RD had the most difficulty, and analysis of their performance suggests a cumulative effect of the two neurodevelopmental disorders in motor adaptation.

Background: Since 1990's, the cognitive profile of children with a neurofibromatosis type 1 (NF1) has been refined by many different studies. Children with NF1 may exhibit a variety of cognitive dysfunctions. Memory difficulties have been reported, but the results are contradictory and, compared to other cognitive functions, memory has been less evaluated., Objective: The aim of this study was to investigate the memory profile in NF1 with a particular population, children with NF1 without attention deficit hyperactivity disorder (ADHD)., Methods: Eighteen children with NF1 without ADHD and eighteen typically developing aged from 8 to 12.6 years were compared in terms of both their verbal and visual working memory, anterograde memory, and procedural perceptual-motor memory. We also assessed semantic and autobiographical memory., Results: Our results indicate the existence of memory difficulties in children with NF1 without ADHD in verbal working and anterograde memory but not in terms of the visual domain. They also experienced difficulties recalling personal memories but these were improved by cueing. However, semantic memory and procedural perceptual-motor memory was preserved., Conclusions: These results highlight a difference between memory systems in children with NF1 without ADHD and the importance to assess the different memory systems, the nature of information and the processes in long-term memory in NF1 population. However, our results raise questions about the possible links between these difficulties and the executive functions. The specifics of memory profile in children with NF1 must be taken into consideration in these children's clinical follow-up, in order to understand their learning difficulties and to make adaptations to their care., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Conflict of interest disclosures No potential conflict of interest was reported by the authors., (Copyright © 2022. Published by Elsevier B.V.)

Aims: The Little Developmental Coordination Disorder Questionnaire (LDCDQ) is a parental questionnaire designed to identify preschool children at risk of Developmental Coordination Disorder (DCD). This study aimed to translate and cross-culturally adapt the LDCDQ for French European informants (Little Developmental Coordination Disorder Questionnaire-French European [LDCDQ-FE]) and to undertake a pilot examination of its psychometric properties on a French sample., Methods: A thorough process of cultural adaptation was completed. The psychometric properties were examined with a sample of 154 French children aged to 5y11m (control = 121; clinically referred = 33). A sub-group of 34 children was assessed using the MABC-2 to measure convergent validity., Results: Principal component analysis demonstrated a four-component structure, accounting for 67.5% of the variance. Internal consistency was acceptable to good ( α  = 0.74-0.89). Significant correlation between the LDCDQ-FE and the MABC-2 total scores showed convergent validity. Discriminant validity was supported by significant score differences between the clinically referred and a matched control sub-group. Using ROC curves, a cutoff of 67 was proposed for a sensitivity of 81.3% and a specificity of 77.8%., Conclusions: Results show initial evidence of the psychometric properties of the LDCDQ-FE and are encouraging of its use to identify young preschoolers at risk for DCD. In future studies, the test-retest reliability should be investigated, and study sample sizes expanded.

The present study investigates procedural learning of motor sequences in children with developmental coordination disorder (DCD) and/or developmental dyslexia (DD), typically-developing children (TD) and healthy adults with a special emphasis on (1) the role of the nature of stimuli and (2) the neuropsychological functions associated to final performance of the sequence. Seventy children and ten adults participated in this study and were separated in five experimental groups: TD, DCD, DD, and DCD + DD children and adults. Procedural learning was assessed with a serial reaction time task (SRTT) that required to tap on a specific key as accurately and quickly as possible when stimuli appeared on the screen. Three types of stimuli were proposed as cues: the classical version of the SRTT with 4 squares aligned horizontally on the screen, giving visuospatial cues (VS cues), and two modified versions, with 4 letters aligned horizontally on the screen (VS + L cues) and letters at the center of the screen (L cues). Reaction times (RT) during the repeated and random blocks allowed assessing three phases of learning: global learning, specific learning and retention of the sequence. Learning was considered as completed when RT evolved significantly in the three phases. Neuropsychological assessment involved, among other functions, memory and attentional functions. Our main result was that learning and retention were not influenced by the available cues in adults whereas learning improved with specific cues in children with or without neurodevelopmental disorders. More precisely, learning was not completed with L cues in children with neurodevelopmental disorders. For children with DD, learning was completed with the VS and VS + L cues whereas for children with DCD (with or without DD), learning was completed with combined VS + L cues. Comorbidity between DD and DCD had no more impact on procedural learning than DCD alone. These results suggest that learning depends on the nature of cues available during practice and that cues allowing learning and retention depend on the type of disorder. Moreover, selective attention was correlated with RT during retention, suggesting that this neuropsychological function is important for procedural learning whatever the available cues., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Blais, Jucla, Maziero, Albaret, Chaix and Tallet.)

Background: The revised version of the Developmental Coordination Disorder Questionnaire (DCDQ'07) is a parent questionnaire designed to identify Developmental Coordination Disorder in 5-15-year-old children., Aim: The aim of this study was to carry out the translation and cross-cultural adaptation of the DCDQ'07, to examine psychometric properties, and to define the cut-off scores of the Arabic-Lebanese version of the questionnaire (DCDQ-AL)., Method: 38 parents of children with and without motor difficulties participated in the translation and cross-cultural phase. As for the validation phase and the study of the psychometric properties, a total of one hundred and twenty-four typically developing children (N=124) aged between 5 and 15 years were recruited through schools in different districts across Lebanon, whereas the clinical sample (N = 56) of children with motor difficulties was recruited via psychomotor rehabilitation centers in Beirut and psychomotor therapists working in private clinics across the country. This study used the Movement Assessment Battery for Children - second edition (MABC-2) motor test developed to classify children according to their degree of motor impairment., Results: For test-retest reliability and inter-rater reliability, excellent Intraclass Correlation Coefficients (ICC) were shown with values of 0.94 and 0.9, respectively. The internal consistency value for the DCDQ-AL was high (Cronbach's alpha = 0.947). Correlations between the DCDQ-AL scores and Movement Assessment Battery for Children (MABC-2) show adequate convergent validity (ρ = 0.65, p < .001). Differences in DCDQ-AL scores between children with and without motor difficulties (p < .001) provide clear evidence of discriminative validity. The Lebanese cut-offs are very similar to the Canadian version, except for the 5-7 age band. The DCDQ-AL shows a sensitivity of 0.91 and specificity of 0.77. The adapted questionnaire showed solid psychometric properties, allowing us to conclude that the DCDQ-AL can be used to support a diagnosis of DCD., Conclusion: The results provide evidence that the DCDQ-AL is a valid clinical screening tool for DCD that can assist Arabic speaking professionals in screening children aged 5-15 years old who are at risk of having DCD., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study investigates the procedural learning, retention, and reactivation of temporal sensorimotor sequences in children with and without developmental coordination disorder (DCD). Twenty typically-developing (TD) children and 12 children with DCD took part in this study. The children were required to tap on a keyboard, synchronizing with auditory or visual stimuli presented as an isochronous temporal sequence, and practice non-isochronous temporal sequences to memorize them. Immediate and delayed retention of the audio-motor and visuo-motor non-isochronous sequences were tested by removing auditory or visual stimuli immediately after practice and after a delay of 2 h. A reactivation test involved reintroducing the auditory and visual stimuli after the delayed recall. Data were computed via circular analyses to obtain asynchrony, the stability of synchronization and errors (i.e., the number of supplementary taps). Firstly, an overall deficit in synchronization with both auditory and visual isochronous stimuli was observed in DCD children compared to TD children. During practice, further improvements (decrease in asynchrony and increase in stability) were found for the audio-motor non-isochronous sequence compared to the visuo-motor non-isochronous sequence in both TD children and children with DCD. However, a drastic increase in errors occurred in children with DCD during immediate retention as soon as the auditory stimuli were removed. Reintroducing auditory stimuli decreased errors in the audio-motor sequence for children with DCD. Such changes were not seen for the visuo-motor non-isochronous sequence, which was equally learned, retained and reactivated in DCD and TD children. All these results suggest that TD children benefit from both auditory and visual stimuli to memorize the sequence, whereas children with DCD seem to present a deficit in integrating an audio-motor sequence in their memory. The immediate effect of reactivation suggests a specific dependency on auditory information in DCD. Contrary to the audio-motor sequence, the visuo-motor sequence was both learned and retained in children with DCD. This suggests that visual stimuli could be the best information for memorizing a temporal sequence in DCD. All these results are discussed in terms of a specific audio-motor coupling deficit in DCD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Blais, Jucla, Maziero, Albaret, Chaix and Tallet.)

Rhythmic abilities are impaired in developmental coordination disorder (DCD) but learning deficit of procedural skills implying temporal sequence is still unclear. Current contradictory results suggest that procedural learning deficits in DCD highly depend on learning conditions. The present study proposes to test the role of sensory modality of stimulations (visual or auditory) on synchronization, learning, and retention of temporal verbal sequences in children with and without DCD. We postulated a deficit in learning particularly with auditory stimulations, in association with atypical cortical thickness of three regions of interesting: sensorimotor, frontal and parietal regions. Thirty children with and without DCD (a) performed a synchronization task to a regular temporal sequence and (b) practiced and recalled a novel non-regular temporal sequences with auditory and visual modalities. They also had a magnetic resonance imaging to measure their cortical thickness. Results suggested that children with DCD presented a general deficit in synchronization of a regular temporal verbal sequence irrespective of the sensory modality, but a specific deficit in learning and retention of auditory non-regular verbal temporal sequence. Stability of audio-verbal synchronization during practice correlated with cortical thickness of the sensorimotor cortex. For the first time, our results suggest that synchronization deficits in DCD are not limited to manual tasks. This deficit persists despite repeated exposition and practice of an auditory temporal sequence, which suggests a possible alteration in audio-verbal coupling in DCD. On the contrary, control of temporal parameters with visual stimuli seems to be less affected, which opens perspectives for clinical practice., (© 2020 John Wiley & Sons Ltd.)

Developmental dyslexia (DD) and developmental coordination disorder (DCD) are distinct diagnostic disorders. However, they also frequently co-occur and may share a common etiology. It was proposed conceptually a neural network framework that explains differences and commonalities between DD and DCD through impairments of distinct or intertwined cortico-subcortical connectivity pathways. The present study addressed this issue by exploring intrinsic cortico-striatal and cortico-cerebellar functional connectivity in a large ( n  = 136) resting-state fMRI cohort study of 8-12-year-old children with typical development and with DD and/or DCD. We delineated a set of cortico-subcortical functional circuits believed to be associated with the brain's main functions (visual, somatomotor, dorsal attention, ventral attention, limbic, frontoparietal control, and default-mode). Next, we assessed, using general linear and multiple kernel models, whether and which circuits distinguished between the groups. Findings revealed that somatomotor cortico-cerebellar and frontoparietal cortico-striatal circuits are affected in the presence of DCD, including abnormalities in cortico-cerebellar connections targeting motor-related regions and cortico-striatal connections mapping onto posterior parietal cortex. Thus, DCD but not DD may be considered as an impairment of cortico-subcortical functional circuits., (© The Author(s) 2020. Published by Oxford University Press.)

Developmental coordination disorder (DCD) is a neurodevelopmental disorder that affects children's ability to execute coordinated motor actions, resulting in slow, clumsy, or inaccurate motor performances and learning difficulties (of new motor tasks or to adapt previously learned gestures to a modified or additional constraint). In the course of development, children with DCD exhibit a diversity of motor signs, including fine and gross motor problems with impaired postural control and balance, and sensorimotor coordination or motor learning difficulties. The prevalence ranges between 1.8% and 8%, depending on the diagnostic criteria used, based on the cutoff of motor scores from standardized scales. Four main hypotheses have been postulated to explain DCD in terms of deficits in visuospatial functions, procedural learning, internal modeling, or executive functions. Neuroimaging studies are scarce but have highlighted several brain regions, including the parietal, frontal, and cerebellar cortices. Meta-analyses have supported task-oriented approaches as effective therapies to improve motor performance in children with DCD., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Children with developmental coordination disorder also manifest difficulties in non-motor domains (attentional, emotional, behavioral and socialization skills). Longitudinal studies can help disentangle the complex relationships between the development of motor skills and other cognitive domains. This study aims to examine the contribution of early cognitive factors to changes in motor skills during the preschool period. Children (N = 1144) from the EDEN mother-child cohort were assessed for motor skills with the Copy Design task (NEPSY battery) and the parent-rated Ages and Stages Questionnaire (fine and gross motor skills scores) at ages 3 and 5-6 years. At 3 years, language skills were evaluated using tests from the NEPSY and ELOLA batteries. Emotional problems, conduct problems, inattention and hyperactivity symptoms, peer relationships and pro-social behavior were assessed with the Strengths and Difficulties Questionnaire (SDQ) also at 3 years. Linear and logistic regression models were performed to examine whether positive and negative changes in motor skills between 3 and 5-6 years are associated with specific cognitive skills at 3 years, while adjusting for a broad range of pre- and postnatal environmental factors. In the linear regression model, the SDQ Inattention symptoms score at 3 years was associated with negative changes in motor skills (standardized β = - 0.09, SD = 0.03, p value = 0.007) and language skills at 3 years were associated with positive changes in motor skills (standardized β = 0.05, SD = 0.02, p value = 0.041) during the preschool period. In logistic regression models, the SDQ Inattention symptoms score at 3 years was associated with a higher likelihood of a declining trajectory of motor skills (OR [95% CI] = 1.37 [1.02-1.84]). A higher language skills score at 3 years was associated with an increased likelihood of a resilient trajectory (1.67 [1.17-2.39]). This study provides a better understanding of the natural history of developmental coordination delays by identifying cognitive factors that predict changes in motor skills between the ages of 3 and 5-6 years.

Impairment of motor learning skills in developmental coordination disorder (DCD) has been reported in several studies. Some hypotheses on neural mechanisms of motor learning deficits in DCD have emerged but, to date, brain-imaging investigations are scarce. The aim of the present study is to assess possible changes in communication between brain areas during practice of a new bimanual coordination task in teenagers with DCD (n = 10) compared to matched controls (n = 10). Accuracy, stability and number of mirror movements were computed as behavioural variables. Neural variables were assessed by electroencephalographic coherence analyses of intra-hemispheric and inter-hemispheric fronto-central electrodes. In both groups, accuracy of the new coordination increased concomitantly with right intra-hemispheric fronto-central coherence. Compared to typically developing teenagers, DCD teenagers presented learning difficulties expressed by less stability, no stabilization of the new coordination and a greater number of mirror movements despite practice. These measures correlated with reduced inter-hemispheric communication, even after practice of the new coordination. For the first time, these findings provide neuro-imaging evidence of a kind of inter-hemispheric 'disconnection' related to altered inhibition of mirror movements during motor learning in DCD., (© 2017 John Wiley & Sons Ltd.)

Research into haptic perception has mostly focused on 3-dimensional objects, and more needs to be known about the processing of 2-dimensional materials (e.g., raised dots and lines and raised-line shapes, patterns and pictures). This study examines the age-related changes in various skills related to the haptic exploration of 2-dimensional raised-line and dot materials and how these skills are related to haptic picture perception. Ninety-one participants, aged 4 years to adult, were asked to perform a series of haptic tasks that entailed (a) finding dots and following lines; (b) matching elements based on texture, shape, and size; (c) matching elements based on spatial location and orientation; (d) memorising sequences of dots and shapes; and (e) identifying complete and incomplete raised-line pictures. On all the tests, the results showed that scores improved with age. Shape discrimination scores accounted for variability in comprehension scores for outline pictures. We suggested that identifying tactile pictures by touch improved with age and mainly depended on the improvement of shape discrimination skills. (PsycINFO Database Record, ((c) 2018 APA, all rights reserved).)

Little attention is paid to motor control in Alzheimer's disease (AD) although it is a relevant sign of central nervous system integrity and functioning. In particular, unimanual and bimanual tapping is a relevant paradigm because it requires intra- and inter-hemispheric transfer (IHT). Previous results indicate that both unimanual and anti-phase tapping requires more IHT than in-phase tapping, especially produced without external stimulation. The aim of the present study was to test the production of unimanual, bimanual in-phase and anti-phase tapping with a synchronization-continuation paradigm with and without visual stimulation in AD patients (N=9) and control participants (N=12). In accordance with our hypothesis, these results suggest that unimanual and anti-phase tapping is more altered in AD than in control participants. Moreover, performance is globally more variable in the AD group. These alterations are discussed in terms of possible IHT modulation, in line with functional and structural findings in AD, revealing changes in the connectivity of brain regions across hemispheres and white matter damage., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Developmental dyslexia (DD) and developmental coordination disorder (DCD) co-occur frequently, raising the underlying question of shared etiological bases. We investigated the cognitive profile of children with DD, children with DCD, and children with the dual association (DD + DCD) to determine the inherent characteristics of each disorder and explore the possible additional impact of co-morbidity on intellectual, attentional, and psychosocial functioning. The participants were 8- to 12-year-olds (20 DD, 22 DCD, and 23 DD + DCD). Cognitive abilities were assessed by the Wechsler Intelligence Scale for Children - Fourth Edition (WISC-IV) and the Continuous Performance Test - Second Edition (CPT-II) and behavioral impairments were evaluated by the Child Behavior Checklist (CBCL). No differences were found between the three groups on attention testing (CPT-II) or psychosocial characteristics (CBCL), but a higher percentage of DD + DCD children had pathological scores on psychosocial scales. Significant between-group differences were observed on Processing Speed Index scores and the block design and symbol search subtests, where DD children fared better than DCD children. No significant differences were evident between the co-morbid vs. the pure groups. Our results clearly show significant differences between children with DD only and children with DCD only. In particular, visuo-spatial disabilities and heterogeneity of intellectual profile seem to be good markers of DCD. However, it should be noted that despite these distinct and separate characteristics, a common cognitive profile (weaknesses and strengths) is likely shared by both neurodevelopmental disorders. Surprisingly, concerning co-morbidity, DD + DCD association is not associated with a decrease in intellectual or attentional capacities.

Objective: Recent theories hypothesize that procedural learning may support the frequent overlap between neurodevelopmental disorders. The neural circuitry supporting procedural learning includes, among others, cortico-cerebellar and cortico-striatal loops. Alteration of these loops may account for the frequent comorbidity between Developmental Coordination Disorder (DCD) and Developmental Dyslexia (DD). The aim of our study was to investigate cerebral changes due to the learning and automatization of a sequence learning task in children with DD, or DCD, or both disorders., Method: fMRI on 48 children (aged 8-12) with DD, DCD or DD + DCD was used to explore their brain activity during procedural tasks, performed either after two weeks of training or in the early stage of learning., Results: Firstly, our results indicate that all children were able to perform the task with the same level of automaticity, but recruit different brain processes to achieve the same performance. Secondly, our fMRI results do not appear to confirm Nicolson and Fawcett's model. The neural correlates recruited for procedural learning by the DD and the comorbid groups are very close, while the DCD group presents distinct characteristics. This provide a promising direction on the neural mechanisms associated with procedural learning in neurodevelopmental disorders and for understanding comorbidity., (Published by Elsevier Ltd.)

This study tested the learning of a new bimanual coordination in teenagers with and without Developmental Coordination Disorder (DCD). Both groups improved accuracy of the new coordination. No difference was found on stability. But DCD teenagers exhibited an overall higher number of additional taps, suggesting a persistent lack of motor inhibition during learning. Moreover, teenagers with the lowest scores of motor abilities present the highest number of additional taps. All these results suggest that this number of additional taps (rather than traditional measures of accuracy and stability) could be a good marker of perceptual-motor learning deficit in DCD.

The most common neurodevelopmental disorders (e.g., developmental dyslexia (DD), autism, attention-deficit hyperactivity disorder (ADHD)) have been the subject of numerous neuroimaging studies, leading to certain brain regions being identified as neural correlates of these conditions, referring to a neural signature of disorders. Developmental coordination disorder (DCD), however, remains one of the least understood and studied neurodevelopmental disorders. Given the acknowledged link between motor difficulties and brain features, it is surprising that so few research studies have systematically explored the brains of children with DCD. The aim of the present review was to ascertain whether it is currently possible to identify a neural signature for DCD, based on the 14 magnetic resonance imaging neuroimaging studies that have been conducted in DCD to date. Our results indicate that several brain areas are unquestionably linked to DCD: cerebellum, basal ganglia, parietal lobe, and parts of the frontal lobe (medial orbitofrontal cortex and dorsolateral prefrontal cortex). However, research has been too sparse and studies have suffered from several limitations that constitute a serious obstacle to address the question of a well-established neural signature for DCD.

Background: There is a body of evidence demonstrating comorbidity of motor and cognitive deficit in «idiopathic» developmental disorders. These associations are also found in developmental disorders secondary to monogenic disorders as in Neurofibromatosis type 1 for which the principal complication during childhood is learning disabilities. The comparison of motor impairment between developmental disorders either idiopathic or secondary as in NF1 could help us to better understand the cause of the combined language/motor deficit in these populations., Aim: The aim of this current study was to investigate motor impairment in children with NF1 for which oral language had been specified and then to compare the motors skills of the NF1 group to motor performance of children with Specific Language Disorder (SLD)., Method: Two groups of 49 children between 5 and 12years old were included and compared, the NF1 group and the SLD (Specific Language Disorder) group. Each child completed evaluation involving cognitive, language and motor assessment., Results: In NF1 group, motor impairment was more frequent and more severe and concerned specifically balance rather than manual dexterity or ball skills, compared to a group of children with SLD. This motor impairment was independent of language status in the NF1 group., Conclusions: These results as well as other studies on the same topic could suggest that in NF1 children, fine motor skills impairment would be dependent on the existence of comorbidity with language disorders. Also, that gross motor skills impairment, and more precisely the balance deficit would be characteristic of NF1. This issue encourages studies of procedural learning that can involve the fronto-striatal or the fronto-cerebellar loops according to the type of motor tasks and the stage of learning., (Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

To fill an important gap in the psychometric assessment of children and adolescents with impaired vision, we designed a new battery of haptic tests, called Haptic-2D, for visually impaired and sighted individuals aged five to 18 years. Unlike existing batteries, ours uses only two-dimensional raised materials that participants explore using active touch. It is composed of 11 haptic tests, measuring scanning skills, tactile discrimination skills, spatial comprehension skills, short-term tactile memory, and comprehension of tactile pictures. We administered this battery to 138 participants, half of whom were sighted (n=69), and half visually impaired (blind, n=16; low vision, n=53). Results indicated a significant main effect of age on haptic scores, but no main effect of vision or Age × Vision interaction effect. Reliability of test items was satisfactory (Cronbach's alpha, α=0.51-0.84). Convergent validity was good, as shown by a significant correlation (age partialled out) between total haptic scores and scores on the B101 test (rp=0.51, n=47). Discriminant validity was also satisfactory, as attested by a lower but still significant partial correlation between total haptic scores and the raw score on the verbal WISC (rp=0.43, n=62). Finally, test-retest reliability was good (rs=0.93, n=12; interval of one to two months). This new psychometric tool should prove useful to practitioners working with young people with impaired vision., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objectives: The aim of this study was to create a French equivalent of the revised Algase wandering scale for long-term care (RAWS-LTC)., Methods: The RAWS-LTC French version (F-RAWS-LTC), Mini-Mental State Examination, and Neuropsychiatric Inventory were administered to a sample of 100 institutionalized patients from 12 specialized homes., Results: The mean of the overall F-RAWS-LTC was 2.32 (standard deviation [SD]=0.74, range 1-4), and the mean of each subscale was 2.48 for persistent walking, 1.62 for eloping behavior, and 2.30 for spatial disorientation. The correlation between the overall F-RAWS-LTC and each subscale was between 0.73 (for Spatial Disorientation) and 0.87 (for Persistent Walking). The correlation between the degree of behavioral disturbances and the overall F-RAWS-LTC is 0.42, and the correlation with the cognitive impairment is 0.50. Differences between the wanderers and nonwanderers are significant for the overall F-RAWS-LTC and for all the subscales., Discussion: Data demonstrate the statistical validity of the F-RAWS-LTC., (© The Author(s) 2013.)

The purpose of this study was to test how the sensory modality of rhythmic stimuli affects the production of bimanual coordination patterns. To this aim, participants had to synchronize the taps of their two index fingers with auditory and visual stimuli presented separately (auditory or visual) or simultaneously (audio-visual). This kind of task requires two levels of coordination: (1) sensorimotor coordination, which can be measured by the mean asynchrony between the beat of the stimulus and the corresponding tap and by mean asynchrony stability, and (2) inter-manual coordination, which can be assessed by the accuracy and stability of the relative phase between the right-hand and left-hand taps. Previous studies show that sensorimotor coordination is better during the synchronization with auditory or audio-visual metronomes than with visual metronome, but it is not known whether inter-manual coordination is affected by stimulation modalities. To answer this question, 13 participants were required to tap their index fingers in synchrony with the beat of auditory and/or visual stimuli specifying three coordination patterns: two preferred inphase and antiphase patterns and a non-preferred intermediate pattern. A first main result demonstrated that inphase tapping had the best inter-manual stability, but the worst asynchrony stability. The second main finding revealed that for all patterns, audio-visual stimulation improved the stability of sensorimotor coordination but not of inter-manual coordination. The combination of visual and auditory modalities results in multisensory integration, which improves sensorimotor coordination but not inter-manual coordination. Both results suggest that there is dissociation between processes underlying sensorimotor synchronization (anticipation or reactivity) and processes underlying inter-manual coordination (motor control). This finding opens new perspectives to evaluate separately the possible sensorimotor and inter-manual coordination deficits present in movement disorders.

Objective: There is increasing evidence to suggest that developmental dyslexia (DD) and developmental coordination disorder (DCD) actually form part of a broader disorder. Their frequent association could be justified by a deficit of the procedural memory system, that subtends many of the cognitive, motor and linguistic abilities that are impaired in both DD and DCD. However, studies of procedural learning in these two disorders have yielded divergent results, and in any case no studies have so far addressed the issue of automatization (dual-task paradigm)., Methods: We administered a finger tapping task to participants aged 8-12 years (19 DCD, 18 DD, and 22 with both DD and DCD) to explore procedural learning and automatic movements in these three groups of children, comparing motor performances at the prelearning stage, after 2 weeks of training, and in a post-training dual-task condition., Results: First, results indicated that all the children were able to learn a sequence of movements and even automatize their movements. Second, they revealed between-groups differences in procedural/automatization learning abilities, setting the DCD group apart from the other two. Third, contrary to our expectations concerning comorbidity, they suggested that the DD+DCD association does not have an additional impact on behavioral performances., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Motor memory is the process by which humans can adopt both persistent and flexible motor behaviours. Persistence and flexibility can be assessed through the examination of the cooperation/competition between new and old motor routines in the motor memory repertoire. Two paradigms seem to be particularly relevant to examine this competition/cooperation. First, a manual search task for hidden objects, namely the C-not-B task, which allows examining how a motor routine may influence the selection of action in toddlers. The second paradigm is procedural learning, and more precisely the consolidation stage, which allows assessing how a previously learnt motor routine becomes resistant to subsequent programming or learning of a new - competitive - motor routine. The present article defends the idea that results of both paradigms give precious information to understand the evolution of motor routines in healthy children. Moreover, these findings echo some clinical observations in developmental neuropsychology, particularly in children with Developmental Coordination Disorder. Such studies suggest that the level of equilibrium between persistence and flexibility of motor routines is an index of the maturity of the motor system.

Despite the apparent age-related decline in perceptual-motor performance, recent studies suggest that the elderly people can improve their reaction time when relevant sensory information are available. However, little is known about which sensory information may improve motor behaviour itself. Using a synchronization task, the present study investigates how visual and/or auditory stimulations could increase accuracy and stability of three bimanual coordination modes produced by elderly and young adults. Neurophysiological activations are recorded with ElectroEncephaloGraphy (EEG) to explore neural mechanisms underlying behavioural effects. Results reveal that the elderly stabilize all coordination modes when auditory or audio-visual stimulations are available, compared to visual stimulation alone. This suggests that auditory stimulations are sufficient to improve temporal stability of rhythmic coordination, even more in the elderly. This behavioural effect is primarily associated with increased attentional and sensorimotor-related neural activations in the elderly but similar perceptual-related activations in elderly and young adults. This suggests that, despite a degradation of attentional and sensorimotor neural processes, perceptual integration of auditory stimulations is preserved in the elderly. These results suggest that perceptual-related brain plasticity is, at least partially, conserved in normal aging., (Copyright © 2014 Elsevier B.V. All rights reserved.)

We propose an oscillatory model that is theoretically parsimonious, empirically efficient and biologically plausible. Building on Hollerbach's (Biol Cybern 39:139-156, 1981) model, our Parsimonious Oscillatory Model of Handwriting (POMH) overcomes the latter's main shortcomings by making it possible to extract its parameters from the trace itself and by reinstating symmetry between the [Formula: see text] and [Formula: see text] coordinates. The benefit is a capacity to autonomously generate a smooth continuous trace that reproduces the dynamics of the handwriting movements through an extremely sparse model, whose efficiency matches that of other, more computationally expensive optimizing methods. Moreover, the model applies to 2D trajectories, irrespective of their shape, size, orientation and length. It is also independent of the endeffectors mobilized and of the writing direction.

The present study investigates developmental changes in selective inhibition of symmetric movements with a lateralized switching task from bimanual to unimanual tapping in typically developing (TD) children and with Developmental Coordination Disorder (DCD) from 7 to 10 years old. Twelve right-handed TD children and twelve gender-matched children with DCD and probable DCD produce a motor switching task in which they have (1) to synchronize with the beat of an auditory metronome to produce bimanual symmetrical tapping and (2) to selectively inhibit their left finger's tapping while continuing their right finger's tapping and conversely. We assess (1) the development of the capacity to inhibit the stopping finger (number of supplementary taps after the stopping instruction) and (2) the development of the capacity to maintain the continuing finger (changes in the mean tempo and its variability for the continuing finger's tapping) and (3) the evolution of performance through trials. Results indicate that (1) TD children present an age-related increase in the capacity to inhibit and to maintain the left finger's tapping, (2) DCD exhibits persistent difficulties to inhibit the left finger's tapping, and (3) both groups improve their capacity to inhibit the left finger's movements through trials. In conclusion, the lateralized switching task provides a simple and fine tool to reveal differences in selective inhibition of symmetric movements in TD children and children with DCD. More theoretically, the specific improvement in selective inhibition of the left finger suggests a progressive development of inter-hemispheric communication during typical development that is absent or delayed in children with DCD., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Among psychomotor disorders in children, developmental coordination disorder (DCD) is characterized by a motor skill impairment that interferes with psychomotor development, academic performance and activities of daily living, despite normal intelligence. The main behavioural phenomena (lack of postural control, coordination and motor learning) suggest involvement of cerebellum, basal ganglia and frontal and parietal lobes. Our studies on a synchronisation/syncopation task, with EEG recording (coherence analysis and evoked potential), show that DCD children (8 to 12 years old) exhibit major interindividual variability and do not improve performance with repetition. In younger DCD children, an increase of coherence between fronto-central regions was reported, and, for evoked potential, an increase of motor preparation component and a N100 latency longer than control children. These findings support the idea of a general synchronization disorder in DCD children and furnish elements allowing a better understanding of intra- and interindividual variability., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

The aim of this study was to investigate the effects of an explicit handwriting program introduced during the first grade of elementary school. Grade 1 children (N=23) with an age range of 6.1 to 7.4 yr. (15 girls, 8 boys) were administered an additional handwriting program of two weekly sessions of 45 min. over six weeks. Another group of 19 Grade 1 children (11 girls, 8 boys) received only the regular handwriting program of one weekly session. The Concise Assessment Scale for Children's Handwriting was administered to measure the changes in quality and speed of handwriting. The children given the explicit program showed better quality and speed of handwriting than did the control group. Their handwriting was more regular, with fewer ambiguous letters and fewer incorrect relative heights.

This study investigated how learning a new bimanual coordination pattern affects the attentional resources allotted by the CNS to maintain it throughout the acquisition process. The repertoire of the existing stable coordination patterns was individually evaluated before and after practice in order to detect expected changes with learning. Bistable participants, who initially exhibited stable and accurate coordination patterns at 0 degrees and 180 degrees of relative phase, practiced a 90 degrees pattern, whereas multistable participants, who already mastered the 90 degrees pattern, practiced 135 degrees pattern instead. In a typical dual-task paradigm, all participants had to simultaneously perform a reaction time task that assessed the associated attentional cost. Beyond an overall increase in accuracy, the results revealed a significant decrease in the attentional cost for bistable participants, accompanying the stabilization of the 90 degrees pattern with learning, but not for multistable participants, as the 135 degrees pattern barely stabilized. Pattern stability and attentional cost co-evolve during learning and the process follows two different routes depending on the interplay between the task and the learner's coordination abilities before practice., (Copyright 2009 Elsevier B.V. All rights reserved.)

This paper investigates the hypothesis that the coordination difficulties of DCD children are associated with an increased coherence in the cortical motor regions, which persists with age. Forty-eight children participated in the study (24 DCD and 24 Controls). Their ages ranged from 8 to 13 years, divided into three groups (8-9, 10-11, and 12-13 years old). Children were required to perform finger flexion or extension either in synchrony or in syncopation with a rhythmic metronome, while a 32-channel EEG was recorded. Along with stability measures of motor performance, we analyzed the spectral EEG coherence between intrahemispheric (left frontal/left central; left central/left parietal) and interhemispheric (left central/right central) sites. Spectral coherence assesses functional coupling between distant areas of the brain. Two frequency bands related to sensorimotor activation were chosen: alpha (8-12 Hz) and beta (12-30 Hz). The synchrony task was chosen as a rest condition against which the two syncopation conditions at 0.5 Hz and 1.3 Hz were contrasted. For intrahemispheric comparison, 8-9-year-old DCD children showed that coherence between fronto-central regions increased for both rhythms and conditions, as compared to controls. No difference was found for interhemispheric comparisons. As frontal sites are related to motor planning, our results suggest that youngest DCD children were forced to maintain a high level of pre-programming to compensate for the difficulties caused by the perceptual-motor requirements of the task in light of their coordination disorder.

Developmental dyslexia is a heterogeneous syndrome with a phonological core deficit and frequent association with other developmental disorders. Controversies exist about the influence of motor difficulties frequently encountered in dyslexia. According to different theoretical approaches, these motor impairments would reflect either a frequent co-morbid entity or a cerebellar dysfunction that could constitute the causal factor of reading disabilities. The principal aim of this study was to determine the frequency of motor impairments in a population of children with phonological dyslexia and specify possible links with attention deficit. We analysed retrospectively motor and attention abilities of 58 children with phonological dyslexia. An important sub-group of children with dyslexia (40-57% depending on the severity of motor difficulties) presented a motor impairment affecting co-ordination, balance and manual dexterity suggesting a cerebellar dysfunction. There was a significant association between attention deficit and motor impairments, with a specific impact on balance and co-ordination deficits. The comparison of performance in four groups defined according to the presence versus absence of attention deficit and motor impairment, respectively, were not in favour of a unequivocal causal link between reading disabilities and motor or attention disorders.

We investigated from a dynamic pattern perspective to motor coordination whether the deficiency in motor coordination characterizing Developmental Coordination Disorder children pertains to a general disorder in synchronization leading to a lower stability of the performed coordination pattern, and the extent to which the trouble is linked to attentional capacities. Twenty-four DCD children without ADHD aged eight to thirteen and 60 control children were asked (1) to perform a Continuous Performance Test assessing sustained attention; (2) to flex one finger either in synchrony or in syncopation with a visual periodic signal whose frequency was increased stepwise, assessing synchronization abilities. For the attentional task, percentage of exact responses, number of errors and reaction time were recorded. For the synchronization task, we measured relative phase (i.e., the ratio between the stimulus and the response onset and the time separating two successive stimuli). DCD children were significantly more variable than controls in both conditions and the difficulty in synchronization was unrelated to attentional disorders (ANCOVA). These findings support the idea of a general synchronization disorder in DCD children underlying their poor motor coordination. Moreover, this synchronization disorder does not appear to be strictly dependent on the level of sustained attentional capacities.

This study aims to test the hypothesis that handwriting is governed by the dynamics of non-linear coupled oscillators. Accordingly, its first goal is to identify preferred, basic graphic shapes corresponding to spontaneously stable combinations of the two frequency-locked oscillatory x-y components of the trajectories. Six participants were required to produce 26 ellipsoids of varying eccentricities and orientations presented consecutively on a graphic tablet. These shapes corresponded to a systematic manipulation of the relative phase and the relative amplitude of the oscillators by a constant step. Results showed that among those, only eight ellipsoids were produced in a spontaneous and stable fashion. They were characterized by attraction of nearby shapes, and by a higher accuracy and velocity. Alike all periodic motion, graphic skills, hence handwriting, exhibit preferred coordination patterns, which can be ascribed to the non-linear coupling of two oscillators.

Previous studies have shown the existence of preferred stroke directions and shapes in handwriting. Assuming that such a two- dimensional trajectory formation process relies on the nonlinear coordination between two abstract orthogonal oscillators, a recent study (Athenes et al., in press) investigated the relative stability and the temporal accuracy of such coordination patterns in performing various ellipsoids corresponding to different phase and amplitude relationships between the oscillators. Results showed that only a small subset of the patterns was stable and accurate. The present study tested and verified the assumption that more stable coordination patterns deteriorate less under a speed constraint. In addition, differences between the dominant and nondominant hands gave insights into various effects modulating the stability and accuracy of such preferred patterns. Evidence of preferred coordination patterns and the predictability of their deterioration corroborate the existence of dynamics underlying handwriting in terms of nonlinearly coupled oscillators.

A large number of studies demonstrated the beneficial effects of contextual interference (CI) created by a random practice of different task variations during training on the retention and transfer of motor skills. Current interpretations of this phenomenon assume that random practice engages the subjects in deep and elaborate processing of movement related information, whereas blocked practice results in more superficial processing leading to poorer performance on later retention and transfer tests. According to this line of interpretation, we hypothesised that the complexity of the task to be learned could modulate the effects of CI. If the task is sufficiently complex, it could force the subjects to rely on such elaborate processing, and the beneficial effects of the intertask interference created by random practice could be obscured in that case. We tested this hypothesis by analysing the effects of practice schedule (random vs. blocked), on the acquisition, retention and transfer of learning in a drawing task where subjects had to reproduce accurately, without visual control, geometrical patterns presented on a video screen, as a function of task complexity defined by the number of segments (two, three or four) of each pattern. The results indicated a clear beneficial effect of random over blocked practice on delayed retention and transfer. However, this CI effect was only observed in subjects who learned the simplest movements, and was not observed in subjects who practised the more complex task. These results are discussed in terms of intratask interference created by the planning of multiple movements and the processing of knowledge of results (KR) when the number of drawing movements is increased. These findings support the assumption that the level of cognitive effort in which the subjects are engaged during training is a main factor influencing long-term retention and transfer of motor skills.