Stephan Eliez - Academia.edu (original) (raw)

Papers by Stephan Eliez

Journal of the International Neuropsychological Society, 2021

Objective:Executive functions (EF) and focal attention have been identified as a weakness in the ... more Objective:Executive functions (EF) and focal attention have been identified as a weakness in the profile of 22q11.2 deletion syndrome (22q11DS). However, due to a high variety of tasks used across previous studies, it remains unclear whether impairments may be more pronounced for specific subdomains of EF and focal attention. Furthermore, age-related changes have only been examined in a few studies, so far only yielding a partial view of the overall developmental profile.Method:In a broad age range (8–35 years) composed of longitudinal data, 183 participants (103 diagnosed with 22q11DS) completed an extensive assessment of EF and attention. To get a more comprehensive overview of specific versus global impairments, several tasks were assessed within multiple domains.Results:Results suggest differential impairments and trajectories in specific EF subdomains. Specifically, our findings suggest that individuals with 22q11DS not only showed lower overall inhibition skills, but also that...

Frontiers in Psychiatry, 2021

Background: Previous studies on possible memory deficits in 22q11DS often focused on quantifying ... more Background: Previous studies on possible memory deficits in 22q11DS often focused on quantifying the information memorized, whereas learning processes have been mostly overlooked. Furthermore, methodological differences in task design have made verbal and non-verbal comparison challenging and mixed results have been observed depending on chosen stimuli.Method: 135 participants (78 with 22q11DS) completed a multi-trial memory task modeled after the Rey Auditory Verbal Learning Task, comparing verbal and non-verbal learning as well as retention over time. Performance in the 22q11DS group were compared to controls and learning curves were analyzed.Results: In 22q11DS, slower acquisition of non-verbal material and higher rates of errors in both verbal and non-verbal tasks was observed. After 30 min, free recall performance, when corrected for initial learning rate, was similar between 22q11DS and controls. Conversely, recognition performance was overall weaker for 22q11DS in both modali...

NeuroImage: Clinical, 2018

Journal of Behavioral and Brain Science, 2018

Journal of Neurodevelopmental Disorders, 2018

Translational Psychiatry, 2019

The 22q11.2 Deletion Syndrome (22q11.2 DS) is one of the highest genetic risk factors for the dev... more The 22q11.2 Deletion Syndrome (22q11.2 DS) is one of the highest genetic risk factors for the development of schizophrenia spectrum disorders. In schizophrenia, reduced amplitude of the frequency mismatch negativity (fMMN) has been proposed as a promising neurophysiological marker for progressive brain pathology. In this longitudinal study in 22q11.2 DS, we investigate the progression of fMMN between childhood and adolescence, a vulnerable period for brain maturation. We measured evoked potentials to auditory oddball stimuli in the same sample of 16 patients with 22q11.2 DS and 14 age-matched controls in childhood and adolescence. In addition, we cross-sectionally compared an increased sample of 51 participants with 22q11.2 DS and 50 controls divided into two groups (8–14 and 14–20 years). The reported results are obtained using the fMMN difference waveforms. In the longitudinal design, the 22q11.2 deletion carriers exhibit a significant reduction in amplitude and a change in topogr...

Journal of Neurodevelopmental Disorders, 2018

American journal of medical genetics. Part A, Jan 5, 2018

The 22q11.2 deletion syndrome is caused by non-allelic homologous recombination events during mei... more The 22q11.2 deletion syndrome is caused by non-allelic homologous recombination events during meiosis between low copy repeats (LCR22) termed A, B, C, and D. Most patients have a typical LCR22A-D (AD) deletion of 3 million base pairs (Mb). In this report, we evaluated IQ scores in 1,478 subjects with 22q11.2DS. The mean of full scale IQ, verbal IQ, and performance IQ scores in our cohort were 72.41 (standard deviation-SD of 13.72), 75.91(SD of 14.46), and 73.01(SD of 13.71), respectively. To investigate whether IQ scores are associated with deletion size, we examined individuals with the 3 Mb, AD (n = 1,353) and nested 1.5 Mb, AB (n = 74) deletions, since they comprised the largest subgroups. We found that full scale IQ was decreased by 6.25 points (p = .002), verbal IQ was decreased by 8.17 points (p = .0002) and performance IQ was decreased by 4.03 points (p = .028) in subjects with the AD versus AB deletion. Thus, individuals with the smaller, 1.5 Mb AB deletion have modestly hig...

Journal of neurodevelopmental disorders, 2016

Children affected by the 22q11.2 deletion syndrome (22q11.2DS) have a specific neuropsychological... more Children affected by the 22q11.2 deletion syndrome (22q11.2DS) have a specific neuropsychological profile with strengths and weaknesses in several cognitive domains. Specifically, previous evidence has shown that patients with 22q11.2DS have more difficulties memorizing faces and visual-object characteristics of stimuli. In contrast, they have better performance in visuo-spatial memory tasks. The first focus of this study was to replicate these results in a larger sample of patients affected with 22q11.2DS and using a range of memory tasks. Moreover, we analyzed if the deficits were related to brain morphology in the structures typically underlying these abilities (ventral and dorsal visual streams). Finally, since the longitudinal development of visual memory is not clearly characterized in 22q11.2DS, we investigated its evolution from childhood to adolescence. Seventy-one patients with 22q11.2DS and 49 control individuals aged between 9 and 16 years completed the Benton Visual Ret...

Human brain mapping, 2017

Large-scale brain networks play a prominent role in cognitive abilities and their activity is imp... more Large-scale brain networks play a prominent role in cognitive abilities and their activity is impaired in psychiatric disorders, such as schizophrenia. Patients with 22q11.2 deletion syndrome (22q11DS) are at high risk of developing schizophrenia and present similar cognitive impairments, including executive functions deficits. Thus, 22q11DS represents a model for the study of neural biomarkers associated with schizophrenia. In this study, we investigated structural and functional connectivity within and between the Default Mode (DMN), the Central Executive (CEN), and the Saliency network (SN) in 22q11DS using resting-state fMRI and DTI. Furthermore, we investigated if triple network impairments were related to executive dysfunctions or the presence of psychotic symptoms. Sixty-three patients with 22q11DS and sixty-eighty controls (age 6-33 years) were included in the study. Structural connectivity between main nodes of DMN, CEN, and SN was computed using probabilistic tractography....

Schizophrenia Research, 2017

NeuroImage. Clinical, 2016

Chromosome 22q11.2 deletion syndrome (22q11DS) is a genetic disease known to lead to cerebral str... more Chromosome 22q11.2 deletion syndrome (22q11DS) is a genetic disease known to lead to cerebral structural alterations, which we study using the framework of the macroscopic white-matter connectome. We create weighted connectomes of 44 patients with 22q11DS and 44 healthy controls using diffusion tensor magnetic resonance imaging, and perform a weighted graph theoretical analysis. After confirming global network integration deficits in 22q11DS (previously identified using binary connectomes), we identify the spatial distribution of regions responsible for global deficits. Next, we further characterize the dysconnectivity of the deficient regions in terms of sub-network properties, and investigate their relevance with respect to clinical profiles. We define the subset of regions with decreased nodal integration (evaluated using the closeness centrality measure) as the affected core (A-core) of the 22q11DS structural connectome. A-core regions are broadly bilaterally symmetric and consi...