Ines Mürner-Lavanchy

Visuospatial working memory in very preterm and term born children—Impact of age and performance

Highlights • 41 preterms performed equally to 36 controls on a visuospatial working memory task.• Preterms showed different involvement of frontal areas compared to controls.• Young and low-performing preterms recruited an atypical working memory network.• Older and high-performing preterms recruited a typical network similar to controls.• Findings point toward the use of compensational mechanisms in preterms.

Age, Sex, and Performance Influence the Visuospatial Working Memory Network in Childhood

This study describes the influence of age, sex, and working memory (WM) performance on the visuospatial WM network. Thirty-nine healthy children (7–12 years) completed a dot location functional magnetic resonance imaging (fMRI) task. Percent signal change measured the intensity and laterality indices measured the asymmetry of activation in frontal and parietal brain regions. Old children showed greater intensity of activation in parietal regions than young children but no differences in lateralization were observed. Intensity of activation was similar across sex and WM performance groups. Girls and high WM performers showed more right-sided lateralization of parietal regions than boys and low WM performers.

Delay of cortical thinning in very preterm born children

BACKGROUNDnCortical gray matter thinning occurs during childhood due to pruning of inefficient synaptic connections and an increase in myelination. Preterms show alterations in brain structure, with prolonged maturation of the frontal lobes, smaller cortical volumes and reduced white matter volume. These findings give rise to the question if there is a differential influence of age on cortical thinning in preterms compared to controls.nnnAIMSnTo investigate the relationship between age and cortical thinning in school-aged preterms compared to controls.nnnSTUDY DESIGN AND OUTCOME MEASURESnThe automated surface reconstruction software FreeSurfer was applied to obtain measurements of cortical thickness based on T1-weighted MRI images.nnnSUBJECTSnForty-one preterms (<32weeks gestational age and/or <1500g birth weight) and 30 controls were included in the study (7-12years).nnnRESULTSnIn preterms, age correlated negatively with cortical thickness in right frontal, parietal and inferior temporal regions. Furthermore, young preterms showed a thicker cortex compared to old preterms in bilateral frontal, parietal and temporal regions. In controls, age was not associated with cortical thickness.nnnCONCLUSIONnIn preterms, cortical thinning still seems to occur between the age of 7 and 12years, mainly in frontal and parietal areas whereas in controls, a substantial part of cortical thinning appears to be completed before they reach the age of 7years. These data indicate slower cortical thinning in preterms than in controls.

Delayed development of neural language organization in very preterm born children.

This study investigates neural language organization in very preterm born children compared to control children and examines the relationship between language organization, age, and language performance. Fifty-six preterms and 38 controls (7–12 y) completed a functional magnetic resonance imaging language task. Lateralization and signal change were computed for language-relevant brain regions. Younger preterms showed a bilateral language network whereas older preterms revealed left-sided language organization. No age-related differences in language organization were observed in controls. Results indicate that preterms maintain atypical bilateral language organization longer than term born controls. This might reflect a delay of neural language organization due to very premature birth.

Neural change following different memory training approaches in very preterm born children – A pilot study

Abstract Objective: There is mixed evidence regarding neural change following cognitive training. Brain activation increase, decrease, or a combination of both may occur. We investigated training-induced neural change using two different memory training approaches. Methods: Very preterm born children (aged 7–12 years) were randomly allocated to a memory strategy training, an intensive working memory practice or a waiting control group. Before and immediately after the trainings and the waiting period, brain activation during a visual working memory task was measured using fMRI and cognitive performance was assessed. Results: Following both memory trainings, there was a significant decrease of fronto-parietal brain activation and a significant increase of memory performance. In the control group, no neural or performance change occurred after the waiting period. Conclusion: These pilot data point towards a training-related decrease of brain activation, independent of the training approach. Our data highlight the high training-induced plasticity of the child’s brain during development.

Cortical morphometry and cognition in very preterm and term-born children at early school age

Very preterm birth influences brain development and may result in alterations of cortical morphometry. These structural alterations may interact with cognitive development. The aim of the present study was to investigate the structure-function relationship in school-aged very preterm and term-born control children. A comprehensive neuropsychological test battery was administered to 41 very preterm (<32 weeks of gestation) and 30 term-born control children aged seven to twelve years. The automated method FreeSurfer was used to obtain cortical thickness and cortical surface area measures from T1-weighted MRI images. Regional cortical thickness differed between groups but differences disappeared when controlling for age. Global cortical thickness differed between groups in the right hemisphere (very preterm children>controls). No group differences occurred for cortical surface area. The relationship between cortical morphometry and cognition differed between very preterm and control children. In very preterm children, some cognitive domains correlated positively and others negatively with regional cortical thickness and cortical surface area. Our findings contribute to the understanding of the structure-function relationship in very preterm children and their term-born peers. They add to the notion that this relationship varies depending on the brain region and the cognitive function in question and suggest developmental differences between very preterm and term-born children.