Neuropsychological dissociations between motion and form perception suggest functional organization in extrastriate cortical regions in the human brain

In this review of neuropsychological case studies, a number of dissociations are shown between different visual abilities including low-level motion perception, static form perception, form-from-motion perception and biological motion perception. These dissociations reveal counter-intuitive results. Specifically, higher level form-from-motion perception can persist despite deficits in low-level motion perception and static form perception. To account for these dissociations, we present a model of functional organization and identify future directions for investigations of higher order form-from-motion perception.     

Cognitive outcomes of pediatric stroke

A limited number of longitudinal studies have investigated long-term neuropsychological development in the pediatric stroke population. This study retrospectively examines cognitive outcomes in 41 children with a history of stroke, with reference to age at stroke, laterality, region and mechanism of stroke. In the course of recovery, neuropsychological measures of intellectual functioning and memory were administered at two time points, whilst executive functioning, attention and academic skills were administered at one time point. As predicted, children with stroke performed significantly worse compared to normative expectations on all neuropsychological measures. Up to two thirds of children scored in the borderline impaired and impaired ranges on at least one domain of cognition. Performance on intellectual and memory assessment remained relatively stable over time. Younger age at stroke was found to be associated with poorer intellectual functioning. No effects of laterality of stroke on neuropsychological performance over time were found. Children with subcortical stroke demonstrated a greater improvement in immediate memory over time than children with cortical stroke. These findings reveal that children with stroke display long-term cognitive difficulties that typically remain stable over time. Attention and academic skills are particularly vulnerable to impairment. Further evidence that age at stroke is a significant factor in terms of cognitive outcome is provided, in support of the “early vulnerability” position.     

The Stroop test: A developmental study in a French children sample aged 7 to 12 years

The Stroop test is a commonly used task in psychology to assess executive function and more specifically inhibition. International studies consistently show improved Stroop task performance with age, whereas available French normative data displays the opposite pattern, with poor clinical sensibility (Albaret & Migliore, 1999). To provide an alternative and useful Stroop test for children, we examined developmental data based on a well-known French protocol validated in adult (GREFEX study group, 2001). The three-standard conditions of the Stroop task (i.e. naming, reading and interference) were administered to 120 typically developing school children (7–12 years), while taking into account the effects of gender, parental educational level and intelligence (both crystallized and fluid intelligence, as measured by the Wechsler intelligence scale). The time to complete each condition (in seconds) was recorded, as well as the number of uncorrected and corrected errors. Results show a continuous increase of performance in “reading” and “naming” control conditions between 7 and 12 years, suggesting an improvement in the lexical access speed and the automation of decoding abilities during reading. Most importantly, a significant reduction of time Stroop effect with age was found (difference between interference and naming conditions), but no interaction with gender. Stroop performances are related to fluid intelligence once age is statistically controlled, but not to parental educational level. The developmental pattern found from the Stroop GREFEX version is consistent with international data and more broadly with executive function and inhibition development. These findings open the prospect of useful normative standardization of this task, with valuable clinical applications perspectives.     

Action planning and position sense in children with Developmental Coordination Disorder

The present study examined action planning and position sense in children with Developmental Coordination Disorder (DCD). Participants performed two action planning tasks, the sword task and the bar grasping task, and an active elbow matching task to examine position sense. Thirty children were included in the DCD group (aged 6–10 years) and age-matched to 90 controls. The DCD group had a MABC-2 total score ⩽5th percentile, the control group a total score ⩾25th percentile. Results from the sword-task showed that children with DCD planned less for end-state comfort. On the bar grasping task no significant differences in planning for end-state comfort between the DCD and control group were found. There was also no significant difference in the position sense error between the groups. The present study shows that children with DCD plan less for end-state comfort, but that this result is task-dependent and becomes apparent when more precision is needed at the end of the task. In that respect, the sword-task appeared to be a more sensitive task to assess action planning abilities, than the bar grasping task. The action planning deficit in children with DCD cannot be explained by an impaired position sense during active movements.     

Comparison of motor praxis and performance in children with varying levels of developmental coordination disorder

The praxis test is a less well-documented method to determine functional manifestations of childhood dyspraxia. For this study, children aged 6–8 years were recruited as follows: 17 children with DCD, 18 at risk of DCD and 35 without obvious problems in motor coordination. The Movement Assessment Battery for Children (MABC-2) was used to measure motor performance and identify the motor incoordination. This study developed a battery of tests to assess limb praxis using a praxis imagery questionnaire, gesture representation, and questions about knowledge of object use. In the comparison of subtests within the praxis test, significant differences were observed across groups on the praxis imagery questionnaire and gesture representation tests but not on knowledge of object use. Similar results were observed in the correlation analyses, in which a weak relationship between MABC-2 and praxis tests was observed. The DCD group had lower scores on the praxis imagery questionnaire, whereas the group at risk of DCD had lower scores on most gesture production tests. Our study provides a better understanding of the nature of the childhood dyspraxia and sheds light on its effect on motor coordination to identify praxis tests with specific clinical meanings in children with movement disorders.     

Happier,faster: Developmental changes in the effects of mood and novelty on responses

Positive mood ameliorates several cognitive processes: It can enhance cognitive control, increase flexibility, and promote variety seeking in decision making. These effects of positive mood have been suggested to depend on frontostriatal dopamine, which is also associated with the detection of novelty. This suggests that positive mood could also affect novelty detection. In the present study, children and adults saw either a happy or a neutral movie to induce a positive or neutral mood. After that, they were shown novel and familiar images. On some trials a beep was presented over headphones either at the same time as the image or at a 200-ms stimulus onset asynchrony (SOA), and the task of the participant was to detect these auditory targets. Children were slower in responding than adults. Positive mood, however, speeded responses, especially in children, and induced facilitatory effects of novelty. These effects were consistent with increased arousal. Although effects of novelty were more consistent with an attentional response, in children who had watched a happy movie the novel images evoked a more liberal response criterion, suggestive of increased arousal. This suggests that mood and novelty may affect response behaviour stronger in children than in adults.     

La fonction argumentative des marques de la langue

The present paper reports a set of experimental studies concerning the comprehension of French argumentative operators and connectives. The first part is a presentation of the theoretical framework, the methodological problems and some of the most general results. Experiments were carried out in the perspective of the linguistic theory of argumentation developed by Anscombre and Ducrot. According to this theory, a number of devices in language are mainly defined by their argumentation function, i.e. by the types of discursive sequences and conclusions they involve. Three categories of such devices were examined: (1) operators like “presque” (almost), “à peine” (hardly), “au moins” (at least), etc. which give an argumentative orientation to the statement; (2) co-orientation connectives, like “même” (even), which relate two statements oriented towards the same conclusion; (3) counter-orientation connectives, like the concessive ones (“mais” (but), “quand même” (even so), etc.), which relate two statements oriented towards opposite conclusions. The data shed light on issues such as: What is the nature of the relationship between the informative and argumentative functions of different operators? Is there a hierarchical relation between the argumentative processes of “co-orientation” and “counter-orientation”? What is the role of negation in the processing of argumentative sequences? The second part of the paper focuses specifically on the study of how 8 and 10 year-old children process “counter-oriented” statements. Five concessive connectives were studied: “mais”, “pourtant”, “quand même”, “même si”, “bien que”. The test was composed of two successive completion tasks: in one task the children had to choose the relevant context of complex sentences involving concessive connectives; in the other task they had to choose their relevant conclusion. Main results show a clear evolution in the performance of children between 8 and 10, suggesting that concessive strategies are not completely mastered at the age of 8. Differences among the concessive connectives studied were brought out: the item “quand même” obtained much better results than the other items with 8-year-old subjects; statements with “mais” seemed to be better processed in the conclusion task than in the context task, especially by 10-year-old subjects. These results are compared with other data obtained in some of the numerous studies on the production and comprehension of concessive connectives in various languages, and discussed from the point of view of argumentative theory.     

Multiple component agraphia in a patient with atypical cerebral dominance: an error analysis

A 52-year-old man with atypical cerebral dominance (left-handed for writing but mixed handedness for other tasks) suffered an extensive right hemisphere stroke, resulting in a combination of deficits that has not been previously reported. There were profound visual constructive and visual perceptual disturbances and a spatial agraphia, which were consistent with a nondominant hemisphere lesion. There was also a severe apraxic agraphia, which is typically associated with a dominant hemisphere lesion, but no other signs of dominant hemisphere dysfunction such as linguistic disturbance or limb-motor apraxia were present. This case serves to highlight the functional and anatomical relationship between handwriting and other forms of praxis; the various sources of error in letter formation; the need to be specific in labeling and describing agraphias ; and the role of a detailed analysis of writing errors in delineating the neuropsychological processes involved in handwriting.     

Manual performance asymmetries and motor control processes: Subject-generated changes in response parameters

Performance asymmetries between the hands have recently been explained in terms of differences in the nature of motor control processes between the hands. If performance asymmetries between the hands on a serial tapping task are due to differences in motor control processes, the degree of asymmetry should be sensitive to changes in the manipulated response parameter, speed of tapping. The results strongly supported this prediction. The differences in control processes observed here seem to be explained by the feedback model proposed by Flowers. Alternate models to that of Flowers (1975) are, however, presented.