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Rapid visual-motion integration deficit in autism

Cette recherche se fixe comme objectif de vérifier, d’une part, si le ralentissement du débit de la parole facilite la compréhension verbale, d’autre part, d’évaluer l’efficacité du ralentissement en fonction de la complexité des stimuli chez des enfants porteurs d’autisme.

Un protocole expérimental a consisté à comparer un groupe de 22 enfants porteurs d’autisme, scolarisés en inclusion dans des écoles maternelles, à 40 enfants tout-venant. Les enfants ont passé deux épreuves. La première porte sur la compréhension de 16 concepts verbaux issus du test BOEHM 3, la seconde réside dans la répétition de phrases issues du test NEPSY-2. Nous comparons les résultats des élèves lorsque la parole est ralentie de 30 % ou non (avec le logiciel LOGIRAL).

Nos résultats montrent que le ralentissement est bénéfique pour tous les enfants, avec ou sans autisme. Dans notre première tâche, une amélioration significative de la compréhension de concepts verbaux est d’autant plus forte que le mot-concept évalué est complexe (la paire, la plus courte, le dernier, etc.). Dans la tâche de répétition de phrases, qui expose l’enfant à des niveaux de complexité plus élevés, le ralentissement est d’autant plus efficace que le niveau de complexité n’est pas trop éloigné de ce que l’élève est capable de répéter sans ralentissement.

Le ralentissement de la parole rend plus accessible les apprentissages verbaux principalement lorsqu’ils portent sur des notions situées dans une zone de proche développement. Les résultats de cette recherche apportent aux enseignants et aux éducateurs des pistes pour un meilleur accompagnement des apprentissages des enfants porteurs d’autisme ainsi que des enfants tout-venant.

The aim of this study is to verify if slowing down the flow of speech facilitates verbal comprehension, in particular the comprehension of verbal concepts used by 4- and 6-years-old kids, and if it is even more effective when the stimuli are complex. Our second objective is to check whether slowing down can improve the child's ability to memorize a sentence faithfully in order to repeat it without error.

The experimental sample was composed of 62 pupils aged 4 to 6 years split into two test groups in an elementary school in Meurthe-et-Moselle. One group was made of 22 children with ASD according to the CIM-10 (World Health Organization, 1994) and DSM-5 (American Psychiatric Association, 1985) criteria. The control group was made up of 40 typically-developing children.

The first test focused on the understanding of 16 verbal concepts from the BOEHM 3 test; the second was a sentence repetition from the NEPSY-2 test. We compared the children's results when the teacher's speech was slowed down and when it was not. We slowed down the speech's speed by 30% without distorting the voice using the LOGIRAL app. This free time stretching software, developed by Tardif and Gepner from the University of Aix-Marseille, with the Auticiel company, is very easy to use in schools. The slowing down of audio-visual signals promotes attention and concentration.

Our results show that the slowing down of speech is beneficial for all children, with or without autism. In our first task, we observed a significant improvement in the comprehension of verbal concepts, even more so as the word-concept evaluated was complex (the pair, the shortest, the last one…). In the task of repeating sentences, which exposed the child to higher levels of complexity, the slowing down was all the more effective as the level of complexity was not too far removed from what the pupil was able to repeat without the teacher's slowed down speech.

According to our study, slowing down speech's speed by 30% improved comprehension and memorization for all children and is especially important for children with ASD. It makes verbal learning more accessible, mainly when it relates to concepts located in the zone of proximal development (Vygotski, 1985). Taking such results into consideration can improve the inclusion of young pupils with autism disorders in mainstream classes, effectively making verbal learning more achievable.

Des particularités dans l’exploration visuelle des visages, notamment des yeux et/ou des lèvres, sont caractéristiques des personnes atteintes de troubles du spectre de l’autisme (TSA) et contribuent à expliquer leurs difficultés de communication sociale et/ou verbale. Elles pourraient être en partie liées à la vitesse excessive des informations véhiculées par les visages lors des interactions. Pour tester cette hypothèse, nous avons enregistré, à l’aide d’un oculomètre, chez 23 enfants avec TSA et 29 enfants typiques, les comportements d’exploration visuelle, i.e. le nombre, le temps total et la durée moyenne des fixations visuelles, sur une scène visuelle montrant le visage d’une narratrice racontant une histoire enfantine dans trois vitesses différentes : temps réel (TR), ralentie à 70 % (R70), ralentie à 50 % (R50). Nos principaux résultats indiquent que : les enfants avec TSA regardent moins le visage et la bouche de la narratrice, mais autant ses yeux, que les enfants typiques ; les enfants avec TSA font des fixations visuelles d’une durée moyenne significativement plus longue sur la scène visuelle et particulièrement sur la bouche de la narratrice, en condition R50 comparativement à la vitesse TR ; les enfants ayant un autisme léger passent d’autant plus de temps à explorer le visage de la narratrice, et notamment sa bouche et ses yeux, que la vitesse est ralentie. Ces résultats encourageants confirment que la dynamique faciale est trop rapide pour certains enfants autistes et démontrent que le ralentissement de la dynamique faciale peut stabiliser leur regard sur le visage d’autrui et ses traits internes, qui sont cruciaux pour le développement de la communication verbale et socio-émotionnelle.

Face and gaze avoidance are among the most characteristic and salient symptoms of autism spectrum disorders (ASD). Studies using eye tracking highlighted early and lifelong ASD-specific abnormalities in attention to face such as decreased attention to internal facial features. These specificities could be partly explained by disorders in the perception and integration of rapid and complex information such as that conveyed by facial movements and more broadly by biological and physical environment. Therefore, we wish to test whether slowing down facial dynamics may improve the way children with ASD attend to a face.

We used an eye tracking method to examine gaze patterns of children with ASD aged 3 to 8 (n = 23) and TD controls (n = 29) while viewing the face of a speaker telling a story. The story was divided into 6 sequences that were randomly displayed at 3 different speeds, i.e. a real-time speed (RT), a slow speed (S70 = 70% of RT speed), a very slow speed (S50 = 50% of RT speed). S70 and S50 were displayed thanks to software called Logiral™, aimed at slowing down visual and auditory stimuli simultaneously and without tone distortion. The visual scene was divided into four regions of interest (ROI): eyes region; mouth region; whole face region; outside the face region. The total time, number and mean duration of visual fixations on the whole visual scene and the four ROI were measured between and within the two groups.

Compared to TD children, children with ASD spent significantly less time attending to the visual scenes and, when they looked at the scene, they spent less time scanning the speaker's face in general and her mouth in particular, and more time looking outside facial area. Within the ASD group mean duration of fixation increased on the whole scene and particularly on the mouth area, in R50 compared to RT. Children with mild autism spent more time looking at the face than the two other groups of ASD children, and spent more time attending to the face and mouth as well as longer mean duration of visual fixation on mouth and eyes, at slow speeds (S50 and/or S70) than at RT one.

Slowing down facial dynamics enhances looking time on face, and particularly on mouth and/or eyes, in a group of 23 children with ASD and particularly in a small subgroup with mild autism. Given the crucial role of reading the eyes for emotional processing and that of lip-reading for language processing, our present result and other converging ones could pave the way for novel socio-emotional and verbal rehabilitation methods for autistic population. Further studies should investigate whether increased attention to face and particularly eyes and mouth is correlated to emotional/social and/or verbal/language improvements.

The mirror neuron (MN) hypothesis of autism has received considerable attention, but to date has produced inconsistent findings. Using functional MRI, participants with high functioning autism or Asperger’s syndrome were compared to typically developing individuals (n = 12 in each group). Participants passively observed hand gestures that included waving, pointing, and grasping. Concerning the MN network, both groups activated similar regions including prefrontal, inferior parietal and superior temporal regions, with the autism group demonstrating significantly greater activation in the dorsal premotor cortex. Concerning other regions, participants with autism demonstrated increased activity in the anterior cingulate and medial frontal gyrus, and reduced activation in calcarine, cuneus, and middle temporal gyrus. These results suggest that during observation of hand gestures, frontal cortex activation is affected in autism, which we suggest may be linked to abnormal functioning of the MN system.