Développement cognitif et performances attentionnelles de l'ancien prématuré « normal » à l'âge scolaire

Neuropsychological assessment of Chilean children with a history of extreme prematurity: An exploratory study

This study was conducted to explore the neuropsychological abilities of premature Chilean children. Two groups (Premature and Control, 10 children each, age ranging from 5 to 7.11) were established based on weeks of gestation and/or weight at birth. Relevant variables such as age, gender, schooling, and socioeconomic level were matched considering Chile's particular demographic context. Children were assessed by means of the Evaluación Neuropsicológica Infantil (ENI-2) battery, measuring nine cognitive domains encompassing 23 subscales. In turn, subscales are grouped in two scales: Cognitive Functions and Executive Functions. Since the ENI-2 battery provides norms for Spanish-speaking children, obtained data were inspected both for possible between-group differences and either adjustment or deviance from average range. Results show that premature children perform within typical ranges in all subscales except for Visual attention and Graphic fluency. When comparing both groups, some differences emerged. These differences are most prominent in subscales related to visuoperceptual skills. Interestingly, between-group linguistic performance is very similar. The point is made that early linguistic interventions conducted on premature children seem to positively impact on oral language expression and comprehension. On the contrary, early interventions focused on visuospatial abilities did not seem to attain the same impact. This may be a consequence of visual-information processing problems derived from cortical dorsal stream's vulnerability, which literature correlates with prematurity.

[Detection of executive function disorders with a standard neurodevelopmental follow-up of premature children]

INTRODUCTION

A significant proportion of prematurely born children encounter behavioral difficulties, such as attention deficit or hyperactivity, which could be due to executive function disorders.

AIMS

To examine whether the standard neurodevelopmental assessment offered to premature children in Switzerland recognizes executive function disorders.

METHODS

The study population consisted of 49 children born before 29 weeks of gestation who were examined between 5 and 6 years of age with a standard assessment, with additional items to assess executive functioning. Children with severe neurodevelopmental impairment were excluded (mental retardation, cerebral palsy, autism). Standard assessment consisted in the Kaufman Assessment Battery for Children (K-ABC), which comprises three subscales: sequential processes (analysis of sequential information), simultaneous processes (global analysis of visual information), and composite mental processes (CMP) (result of the other two scales), as well as a behavioral evaluation using the standardized Strengths and Difficulties Questionnaire (SDQ). Executive functioning was assessed with tasks evaluating visual attention, divided attention, and digit memory as well as with a specialized questionnaire, the Behavior Rating Index of Executive Functions (BRIEF), which evaluates several aspects of executive function (regulation, attention, flexibility, working memory, etc).

RESULTS

Children were divided according to their results on the three K-ABC scales (< or >85), and the different neuropsychological tasks assessing executive function were compared between the groups. The CMP did not differentiate children with executive difficulties, whereas a score < 85 on the sequential processes was significantly associated with worse visual and divided attention. There was a strong correlation between the SDQ and the BRIEF questionnaires. For both questionnaires, children receiving psychotherapy had significantly higher results. Children who presented behavioral problems assessed with the SDQ presented significantly higher scores on the BRIEF.

CONCLUSION

A detailed analysis of the standard neurodevelopmental assessment allows the identification of executive function disorders in premature children. Children who performed below 85 on the sequential processes of the K-ABC had significantly more attentional difficulties on the neuropsychological tasks and therefore have to be recognized and carefully followed. Emotional regulation had a strong correlation with behavioral difficulties, which were suitably assessed with the SDQ, recognized by the families, and treated.

Responses to a modified visual cliff by pre-walking infants born preterm and at term

The purpose of this study was to examine, using a modified visual cliff apparatus, possible perceptual differences at crawling age between infants born preterm and infants born at term without documented visual or motor impairments. Sixteen infants born at term and 16 born preterm were encouraged to crawl to their caregivers on a modified visual cliff. Successful trials, crossing time, duration of visual attention, duration of tactile exploration, motor strategies, and avoidance behaviors were analyzed. A significant surface effect was found, with longer crossing times and longer durations of visual attention and tactile exploration in the condition with the visual appearance of a deep cliff. Although the two groups of infants did not differ on any of the timed measures, infants born at term demonstrated a larger number of motor strategies and avoidance behaviors by simple tally. This study indicates that infants born at term and those born preterm can perceive a visual cliff and adapt their responses accordingly.

Attentional networks efficiency in preterm children

Recent studies have reported specific executive and attentional deficits in preterm children. However, the majority of this research has used multidetermined tasks to assess these abilities, and the interpretation of the results lacks an explicit theoretical backdrop to better understand the origin of the difficulties observed. In the present study, we used the Child Attention Network Task (Child ANT; Rueda et al. 2004) to assess the efficiency of the alerting, orienting and executive control networks. We compared the performance of 25 preterm children (gestational age < or = 32 weeks) to 25 full-term children, all between 5(1/2) and 6(1/2) years of age. Results showed that, as compared to full-term children, preterm children were slower on all conditions of the Child ANT and had a specific deficit in executive control abilities. We also observed a significantly higher correlation between the orienting and executive control networks in the preterm group, suggesting less differentiation of these two networks in this population.