[Autism and neuropsychology]. / Autisme et neuropsychologie.

In neuropsychology, the deficiencies associated with autism are generally classed into three areas: social cognition, executive functioning and central coherence. Autistic people however have singular capacities, notably with regard to their perceptual processing focused on details.

Perceiving goals and actions in individuals with autism spectrum disorders.

In the present study, we investigated the ability to parse familiar sequences of action into meaningful events in young individuals with autism spectrum disorders (ASDs), as compared to young individuals with typical development (TD) and young individuals with moderate mental retardation or learning disabilities (MLDs). While viewing two videotaped movies, participants were requested to detect the boundary transitions between component events at both fine and coarse levels of the action hierarchical structure. Overall, reduced accuracy for event detection was found in participants with ASDs, relative to participants with TD, at both levels of action segmentation. The performance was, however, equally diminished in participants with ASDs and MLDs under the course-grained segmentation suggesting that difficulties to detect fine-grained events in ASDs cannot be explained by a general intellectual dysfunction. Reduced accuracy for event detection was related to diminished event recall, memory for event sequence and Theory of Mind abilities. We hypothesized that difficulties with event detection result from a deficit disrupting the on-line processing of kinematic features and physical changes of dynamic human actions. An impairment at the earlier stages of the event encoding process might contribute to deficits in episodic memory and social functioning in individuals with ASDs.

Predicting ensuing actions in children and adolescents with autism spectrum disorders.

This study investigated the ability to predict others' action in a group of children and adolescents with autism spectrum disorders (ASD) (n = 18). Their performance was compared with a group of children with mental retardation (n = 13) and a group of children with typical development (n = 19). Participants were presented with short incomplete videotaped movies showing an actor executing familiar and non-familiar actions. When asked to predict the outcome, participants with ASD produced fewer correct responses and their performance did not improve for familiar actions, as compared to both comparison groups. In addition, they committed a greater number of errors of temporal inversion. These results provide new evidence that an impaired means-end analysis process, leading to a diminished sensitivity to the sequence structure of goal-directed actions, would disrupt the ability to understand and predict others' actions. The comprehension of abnormalities in event knowledge provides a better insight of some of the problems that individuals with ASD encounter in spontaneously understanding real-life social situations.

Goal-directed action representation in autism.

The aim of the present study was to investigate the ability of individuals with autism to represent goal-directed behavioural actions. We compared the performance of subjects with autism (n=16), mentally retarded subjects (n=14) and normal healthy subjects (n=15) in a sequencing task consisted in arranging pictures of single events in their appropriate order so as to make coherent stories. Three types of actions were presented: (a) actions on objects; (b) actions on objects in a broader spatio-temporal context; (c) interactive actions. Autistic subjects were impaired in arranging sequences of actions on objects, as compared to both control groups. This impairment might contribute to explaining both executive deficits and difficulties in understanding others' behaviour in autism.

Impairment in event sequencing in disorganised and non-disorganised patients with schizophrenia.

It has been suggested that thought disorder in schizophrenia is associated with impaired executive functions and with a defective understanding of others' behaviour. Action sequence knowledge processing and goal detection are considered as crucial components of executive functioning. Here, we used a picture-sequencing task to assess the ability of schizophrenic patients (n = 40) with and without disorganisation symptoms to arrange different types of action sequence representations. Disorganisation symptoms appear to be associated with a general sequencing impairment, while patients without disorganisation symptoms displayed difficulties in ordering sequences requiring subjects to infer mental states in story characters along with a relatively preserved performance in correctly arranging mechanical or behavioural event sequences. These results reveal that only schizophrenic patients without disorganisation symptoms show a selective deficit in mentalising abilities whereas disorganisation symptoms are associated with a more severe event sequencing impairment probably reflecting basic failures of inferential reasoning.

Gaze direction determination in schizophrenia.

It has been proposed that an impairment in gaze determination is responsible for the paranoid symptoms reported in schizophrenia. To address this, we examined the gaze discrimination system in schizophrenia. Thirty-two patients suffering from schizophrenia (20 patients with persecutory delusions and 12 patients without such delusions) were compared to 32 control subjects on two specific tasks. In the first task, the subjects had to determine whether 130 portraits were looking right or left. In the second task the subjects were asked to determine whether or not 130 portraits were looking at them. The absolute threshold of difference used to investigate the influence of instruction on gaze discrimination did not show any difference between patients with schizophrenia, whatever paranoid or not, and control subjects. Paranoid patients, as well as controls, displayed a significantly finer discrimination threshold in the right vs. left judgment than in the self vs. non-self judgment. Subjects with schizophrenia were able to discriminate gaze direction in the two tasks, but they took significantly more time in the task requiring to determine the presence or the absence of a mutual gaze contact than in the other one, whereas controls took the same duration to elicit both tasks. These data are consistent with those reporting that perceptual abilities are spared in schizophrenia while delusions are related to an impairment of a higher level of analysis.