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National audience; A l’exception du léger frottement du stylo sur la feuille, l’écriture est une activité silencieuse. Parce que la modalité auditive est disponible pendant l’écriture et parce qu’elle est particulièrement pertinente pour percevoir des différences fines au plan temporel et dynamique, nous cherchons à comprendre comment l’ajout d’informations auditives permet à un évaluateur externe, le thérapeute dans notre cas, ou au scripteur lui-même d’évaluer et d’améliorer son geste en temps réel. La sonification de certaines caractéristiques motrices de l’écriture nous permet de disposer d’un outil clinique pertinent pour faciliter l’évaluation et la rééducation de la motricité fine dans la Maladie de Parkinson.

International audience; no abstract

The dynamic features of sounds make them particularly appropriate for assessing the spatiotemporal characteristics of movements. Furthermore, sounds can inform about the correctness of an ongoing movement without directly interfering with the visual and proprioceptive feedback. Finally, because of their playful characteristics, sounds are potentially effective for motivating writers in particular need of any writing assistance. By associating relevant sounds to the specific variables of handwriting movement, the present chapter aimed at reporting how supplementary auditory information allows an examiner (teacher or therapist) to assess the movement quality from his/her hearing. Furthermore, a writer could also improve his/her movement from this real-time auditory feedback. Sonification of some movement characteristics would be a relevant tool for the diagnosis and the rehabilitation of some developmental disabilities (e.g. dysgraphia) or acquired disorders (e.g. Parkinson's disease).

International audience; Although almost all motor activities are silent, the modality of sound can be used to inform about the correctness of the ongoing movement, without interfering with the visual and proprioceptive feedback. Furthermore, the dynamic features of sounds make them particularly relevant for informing about the spatiotemporal characteristics of movements. Finally, because of their (potentially) playful character, sounds are potentially efficient for motivating patients, children for instance, in particular need of such assistance. From these theoretical considerations, we proposed to sonify handwriting movements in order to facilitate the rehabilitation of dysgraphia. Dysgraphia refers to mechanical difficulties in handwriting production related to a lack of motor control in children having neither neurological nor other motor deficits. Nowadays, handwriting movements can be recorded with graphic tablets at high temporal and spatial resolution. Two challenges appeared: first, finding the relevant variables associated with the different sounds; second, finding the appropriate auditory dimension(s) on which to map the handwriting movements. We hypothesized that sound is well suited to inform about hidden variables of handwriting movement (which cannot be supplied by vision) and we decided to sonify two kinematic variables: the instantaneous tangential velocity and the unexpected velocity peaks. Unexpected velocity peaks have been shown to be directly related to non-fluent handwriting movements. Finally, the pressure applied by the pen on the graphic tablet was associated with the global volume of the sound. We are currently testing these movement/sound associations in seven dysgraphic children in a longitudinal protocol of handwriting rehabilitation. The experiment is divided into six 20-minutes weekly sessions. Each session is organized in identical manner, including a pre-test without sound, a practice with auditory feedback and a post-test without sound. In the pre- and post-tests, tasks are strictly identical and thus can be used to follow the rehabilitation evolution, within and between sessions. Preliminary data from the three first sessions revealed a positive effect of the sonification procedure: Dysgraphic children appeared to be able to write faster and with more fluent movements. These first promising results will be soon completed with an additional control group in which other dysgraphic children will run the same protocol without auditory feedback, in order to confirm the positive effect of adding sounds. We propose that sounds may be used as a palliative way to inform about kinematics of handwriting movements and, maybe, to assist movement rehabilitation in general.

International audience; Sounds can be used to inform about the correctness of an ongoing movement, without directly interfering with the visual and proprioceptive feedback. Furthermore, the dynamic features of sounds make them particularly appropriate means of accessing the spatiotemporal characteristics of movements. Finally, because of their playful characteristics, sounds are potentially effective for motivating children in particular need of such assistance. Based on these theoretical considerations, the present work investigated the relevance of applying an online auditory feedback to spatiotemporal characteristics of handwriting for the rehabilitation of handwriting learning disabilities.

Handwriting movement is through one of the fastest and the most complex known to human motor behaviors. This ability involves a sophisticated coordination of many muscles and joints recruited in order to produce a trace sufficiently consistentand precise to be recognized as letters. The aim of the present thesis is to understand 1) how we succeed in controlling and coordinating the motor (here graphomotor) system to realize this task and 2) how this motor behavior is acquired. Concepts and tools of the dynamical approach of the motor coordination permit to consider the written trajectory formation as a self-organized process resulting from the dynamics of non-linear coupled oscillators. From the modeling of handwriting movements in terms of the non-linear coupling of two abstractorthogonal oscillators, the relative phase between these oscillators makepossible to observe, to understand and to predict the formation, the maintaining and the deterioration of the written trajectory. In a first study based on graphic coordination of adults in production of simple geometrical shapes, we confirmed that the ellipse with intermediate eccentricity and the line are easier to produce that all other shapes. Moreover, we demonstrated that the preferential production of intermediate ellipse is biased toward a more circular shape when orientation becomes a constraint. In a second study based on graphic coordination of 7 to 11 year-old children, we revealed that children are more precise and stable in circle drawing than in ellipse drawing, preferential in adults. Our results confirm that, as all cycliccoordinated movements,the stability of the motor coordination patterns determine the way of handwriting.; L’écriture est un mouvement parmi les plus complexes et les plus rapides de notre répertoire moteur. Elle requiert l’activité coordonnée de nombreux muscles et articulations du membre supérieur pour produire une succession de formes conventionnelles, des lettres, de manière suffisamment précise pour être reconnues. Ce travail de thèse a pour objectif de comprendre 1) comment les individus arrivent à contrôler et à coordonner l’ensemble des éléments du système moteur (ici graphomoteur) pour accomplir une telle tâche et 2) comment s’acquiert cette habileté motrice. Les concepts et outils de l’approche dynamique de la coordination motrice permettent d’envisager la formation de la trace écrite comme un processus auto-organisé qui répond aux modèles d’oscillateurs couplés. A partir de la modélisation de l’écriture en termes de couplage non linéaire de deux oscillateurs orthogonaux abstraits, la phase relative entre ces deux oscillateurs permetd’observer, de comprendre et de prédire la formation, le maintien et la dégradation de la trace écrite. Dans notre première étude, centrée sur la coordination graphomotrice adulte dansla reproduction de formes géométriques simples, nous avons confirmé qu’une ellipse d’excentricité intermédiaire et un trait sont plus faciles à tracer que toutes les autres formes elliptiques. Nous avons de plus montré que la production préférentielle d’ellipses d’excentricité intermédiaire est biaisée en faveur de formes plus arrondies lorsque leur orientation devient contraignante. Dans notre deuxième étude, centrée sur la coordination graphomotrice chez l’enfant de 7 à 11 ans, nous avons révélé que les enfants sont plus précis et plus stables dans le tracé de cercles que dans le tracé d’ellipses, préférentiel chez l’adulte. Nos résultats confirment que, comme tout mouvement rythmique coordonné, la stabilité des modes de coordination (grapho)motrice détermine la manière d’écrire.

International audience; À partir d’un rapprochement entre deux expériences menées indépendamment sur un même paradigme, le présent article s’intéresse aux contraintes qui influencent la graphomotricité. Une étude princeps menée par Athènes et al. (2004)sur la reproduction de formes graphiques simples montre que cinq formes sont préférentielles lorsque le bras effecteur n’est pas contraint. Lorsque l’avant-bras est fixé, nos résultats suggèrent l’existence de seulement quatre formes préférentielles. Nos résultats suggèrent que l’ajout d’une contrainte liée sur l’effecteur n’a pas forcément un effet délétère sur le paysage graphomoteur. Si cette hypothèse était confirmée par des études ultérieures, il serait possible d’exploiter les résultats dans le but de faire apparaître de nouvelles formes préférentielles qui ne sont pas spontanément reproduites avec précision sans contrainte ajoutée