Franck Ramus

• PhD
• Research Director at Ecole Normale Supérieure de Paris

The present longitudinal study investigated the hypothesis that early musical skills (as measured by melodic and rhythmic perception and memory) predict later literacy development via a mediating effect of phonology. We examined 130 French‐speaking children, 31 of whom with a familial risk for developmental dyslexia (DD). Their abilities in the thr...

We studied the effect of the number and characteristics of siblings (sex, age) on school achievement in several grades (kindergarten, first grade, and fifth grade), in two large French cohorts, with more than 16,000 children. Running linear mixed-effects models, we find that, independently of socioeconomic status, having more siblings is negatively...

Background The associations of screen use with children's cognition are not well evidenced and recent, large, longitudinal studies are needed. We aimed to assess the associations between screen use and cognitive development in the French nationwide birth cohort. Methods Time and context of screen use were reported by parents at ages 2, 3.5 and 5.5...

Girls tend to outperform boys in language development and literacy, but the reasons behind this remain unclear, particularly whether the family environment plays a role. This study examines gender differences in parental linguistic engagement and its effect on language outcomes. Using data from the French birth cohort Elfe (ranging from 14,000 chil...

Girls tend to outperform boys in language development and literacy, but the reasons behind this remain unclear, particularly whether the family environment plays a role. This study examines gender differences in parental linguistic engagement and its effect on language outcomes. Using data from the French birth cohort Elfe (about 12,000 for early o...

This study investigates the impact of gender socialization on early mathematics gender gaps, focusing on children's gendered activities and parental roles. Analyzing data from over 4,000 children (50% girls), we observe that less traditionally organized households correlate with higher preschool academic achievement, irrespective of income or paren...

Mental conditions exhibit a higher-order transdiagnostic factor structure which helps to explain the widespread comorbidity observed in psychopathology. However, the phenotypic and genetic structures of psychopathology may differ, raising questions about the validity and utility of these factors. Here, we study the phenotypic and genetic factor str...

Background: Combined effect of both prenatal and early postnatal exposure to ambient air pollution on child cognition has rarely been investigated and sensitive periods of sensitivity are unknown. This study explores the temporal relationship between pre- and postnatal exposure to PM10, PM2.5, NO2 and child cognitive function. Methods: Using val...

Le mythe de l’usage excessif des écrans associé aux troubles neurodéveloppementaux est largement répandu dans les médias et dans l’opinion publique. En réalité, l’usage du numérique, quand il peut être source d’interactions diverses, est un facteur de développement parmi d’autres. Il est en effet établi que l’usage du numérique, lorsqu’il est média...

Previous studies have reported anomalies in the arcuate fasciculus (AF) lateralization in developmental dyslexia (DD). Still, the relationship between AF lateralization and literacy skills in DD remains largely unknown. The purpose of our study is to investigate the relationship between lateralization of three segments of AF (AF anterior segment (A...

The aim of this study was to provide a comprehensive understanding of the potential linkages between intelligence and psychopathology across the full IQ range, while considering both absolute IQ scores and discrepancies between them. We drew data from the EDEN mother-child birth cohort, gathered at two time points: 5.5 and 11.5 years of age. We exa...

We studied the effect of the number and characteristics of siblings (sex and age), on school achievement in numeracy and literacy from kindergarten to 5th grade, in two large French cohorts (the Elfe cohort, more than 4,400 children, and the DEPP panel, more than 9,500 children). Running linear mixed effects models, we find that, independently of s...

Theory of Mind (ToM) is essential to adapt in social situations; however, a ToM deficit might be involved in autism. To better understand how ToM reasoning affects problem solving in autistic and non-autistic individuals, we compared autistic and non autistic children and adults in a series of problems presented in social and non-social framings, u...

Although genetic and environmental factors influence general intelligence (g-factor), few studies examined the neuroanatomical measures mediating environmental and genetic effects on intelligence. Here, we investigate the brain volumes, cortical mean thicknesses, and cortical surface areas mediating the effects of the g-factor polygenic score (gPGS...

Background Studies reporting that highly intelligent individuals have more mental health disorders often have sampling bias, no or inadequate control groups, or insufficient sample size. We addressed these caveats by examining the difference in the prevalence of mental health disorders between individuals with high and average general intelligence...

UK Biobank participants do not have a high-quality measure of intelligence or polygenic scores (PGSs) of intelligence to simultaneously examine the genetic and neural underpinnings of intelligence. We created a standardized measure of general intelligence (g factor) relative to the UK population and estimated its quality. After running a GWAS of g...

The present study aimed to investigate the role of connectivity disruptions in two fiber pathways, the uncinate fasciculus (UF) and the frontal aslant tract (FAT), in developmental dyslexia and determine the relationship between the connectivity of these pathways and behavioral performance in children with dyslexia. A total of 26 French children wi...

The number of older siblings a child has is negatively correlated with the child's verbal skills, an effect that is well known in the literature. However, few studies have examined the effect of older siblings’ sex, of the age gap between siblings, of having foreign‐speaking parents, as well as the mediating role of parental interaction. Using data...

Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were...

Reading and writing are crucial life skills but roughly one in ten children are affected by dyslexia, which can persist into adulthood. Family studies of dyslexia suggest heritability up to 70%, yet few convincing genetic markers have been found. Here we performed a genome-wide association study of 51,800 adults self-reporting a dyslexia diagnosis...

Previous studies have reported anomalies in the arcuate fasciculus (AF) lateralization in developmental dyslexia (DD). Still, the relationship between AF lateralization and literacy skills in DD remains largely unknown. The purpose of our study is to investigate the relationship between the lateralization of the AF anterior segment (AFAS), AF long...

Although genetic and environmental factors influence general intelligence (g-factor), few studies examined the neuroanatomical measures mediating environmental and genetic effects on intelligence. Therefore, we investigate the brain volumes, cortical mean thicknesses, and cortical surface areas mediating the effects of the g-factor polygenic score...

A converging body of evidence from neuroimaging, behavioral and neuropsychology studies suggests that different arithmetic operations rely on distinct neuro-cognitive processes: while addition and subtraction may rely more on visuospatial reasoning, multiplication would depend more on verbal abilities. In this paper, we tested this hypothesis in a...

The present study aimed to investigate the role of connectivity disruptions in two fiber pathways, the uncinate fasciculus (UF) and the frontal aslant tract (FAT), in developmental dyslexia and determine the relationship between the connectivity of these pathways and behavioral performance in children with dyslexia. A total of 26 French children wi...

It has been suggested that developmental dyslexia may have two dissociable causes—a phonological deficit and a visual attention span (VAS) deficit. Yet, neural evidence for such a dissociation is still lacking. This study adopted a data‐driven approach to white matter network analysis to explore hubs and hub‐related networks corresponding to VAS an...

Objective Studies reporting that highly intelligent individuals have more mental health disorders often have sampling bias, no or inadequate control group, or insufficient sample size. We addressed these caveats by examining the difference in the prevalence of mental health disorders between individuals with high and average general intelligence (g...

Our aim was to create a standardized measure of general intelligence (g) relative to the UK population for UK Biobank participants and derive a g factor polygenic score for UK Biobank participants with neuroimaging data.We first created standardized cognitive test scores that were relative to the UK population based on the participants’ age, sex, a...

Using data from 12,296 children (49.3% female) from the French ELFE birth cohort, we analyzed the effect of various characteristics of the siblings on children’s expressive vocabulary. Children’s vocabulary at age 2 years was negatively associated with the number of older siblings (-.08 SD per additional sibling), and this effect was partly mediate...

The aim of this study was to provide a comprehensive understanding of the potential linkages between intelligence and psychopathology across the full IQ range, while considering both absolute IQ scores and discrepancies between them. We drew data from the EDEN mother-child birth cohort, gathered at two time points: 5.5 and 11.5 years of age. We exa...

Education researchers often refer to “non-cognitive skills” as another set of important skills that influence educational achievement, besides general intelligence. However, upon examination, non-cognitive skills are all cognitive, therefore this usage makes no sense. Non-cognitive skills should be called by their names, such as character, mindset,...

Studies examining cerebral asymmetries typically divide the L-R Measure (e.g., Left–Right Volume) by the L+R Measure to obtain an Asymmetry Index (AI). However, contrary to widespread belief, such a division fails to render the AI independent from the L+R Measure and/or from total brain size. As a result, variations in brain size may bias correlati...

The critique of the genetics of complex social outcomes is partly well-founded, insofar as social outcomes sometimes have unreliable relations with cognitive traits. But the correct conclusion is not to dismiss the entire field altogether. Rather, the implication is to redirect geneticists' attention to the stable cognitive phenotypes that are natu...

Studies examining cerebral asymmetries typically divide the L-R Measure (e.g., Left– Right Volume) by the L+R Measure to obtain an Asymmetry Index (AI). However, contrary to widespread belief, such a division fails to render the AI independent from the L+R Measure and/or from total brain size. As a result, variations in brain size may bias correlat...

The use of spoken and written language is a capacity that is unique to humans. Individual differences in reading- and language-related skills are influenced by genetic variation, with twin-based heritability estimates of 30-80%, depending on the trait. The relevant genetic architecture is complex, heterogeneous, and multifactorial, and yet to be in...

The present study performed a systematic comparison of DSM-5 and ICD-11 diagnostic criteria for reading disability. We quantitatively investigated the consequences of using DSM-5 or ICD-11, and of the different ways of implementing each diagnostic criterion on the prevalence of reading disability. We did so in a representative sample of the populat...

Note Ce travail a bénéficié du soutien du Programme d'Investissements d'Avenir (ANR-17-EURE-0017 and ANR-10-IDEX-0001-02 PSL). Les données sont issues du « Panel d'élèves du second degré Résumé La présente étude effectue une comparaison systématique entre DSM-5 et CIM-11 des critères diagnostiques du trouble de la lecture, dans une population repré...

Spaced retrieval practice consists of repetitions of the same retrieBjorkval event distributed through time. This learning strategy combines two “desirable difficulties”: retrieval practice and spacing effects. We carried out meta-analyses on 29 studies investigating the benefit of spacing out retrieval practice episodes on final retention. The tot...

In their comprehensive review of sex differences in the brain, Eliot et al. (2021) conclude that (1) men and women significantly differ in global brain size, but this “mostly parallels the divergence of male/female body size during development” and that (2) “once we account for individual differences in brain size, there is almost no difference in...

Cognitive theories have been proposed to clarify the causes and symptoms of dyslexia. However, correlations between local network parameters of white matter connectivity and literacy skills remain poorly known. An unbiased hypothesis-free approach was adopted to examine the correlations between literacy symptoms (reading and spelling) and hub-based...

Few neuroimaging studies are sufficiently large to adequately describe population-wide variations. This study's primary aim was to generate neuroanatomical norms and individual markers that consider age, sex, and brain size, from 629 cerebral measures in the UK Biobank (N = 40,028). The secondary aim was to examine the effects and interactions of s...

Developmental dyslexia (DD) is a learning disorder affecting the ability to read, with a heritability of 40-60%. A notable part of this heritability remains unexplained, and large genetic studies are warranted to identify new susceptibility genes and clarify the genetic bases of dyslexia. We carried out a genome-wide association study (GWAS) on 227...

The epidemiology of cognitive development is an approach essentially based on large observational studies, which examines individual differences in cognitive abilities throughout childhood and their determinants. Although different in terms of methodology and main interests from developmental psychology, cognitive epidemiology offers complementary...

Whether phonological deficits in developmental dyslexia are associated with impaired neural sampling of auditory information is still under debate. Previous findings suggested that dyslexic participants showed atypical neural entrainment to slow and/or fast temporal modulations in speech, which might affect prosodic/syllabic and phonemic processing...

The two major medical classifications (ICD-11 and DSM-5), define diagnostic criteria for developmental dyslexia that partly differ and that are open to multiple interpretations, inducing different prevalence estimates and discordant cases. The present study evaluates the prevalence of developmental dyslexia for the first time in France in an extens...

Few neuroimaging studies are sufficiently large to adequately describe population-wide variations. This study's primary aim was to generate neuroanatomical norms and individual markers that consider age, sex, and brain size, from 629 cerebral measures in the UK Biobank (N = 40 028). The secondary aim was to examine the effects and interactions of s...

Are the brain mechanisms of reading acquisition similar across writing systems? And do similar brain anomalies underlie reading difficulties in alphabetic and ideographic reading systems? In a cross-cultural paradigm, we measured the fMRI responses to words, faces and houses in 96 Chinese and French 10-year-old children, half of whom were strugglin...

Information available on the risks of neurodevelopmental disorders (NDs) associated with in utero exposure to valproate (VPA) and to other antiepileptic drugs (AEDs) is limited. A nationwide population-based cohort study was conducted based on comprehensive data of the French National Health Data System (SNDS). Liveborn infants without brain malfor...

Studies on sex differences in academic skills have often reported diverging results depending on the type of evaluation used, with girls typically obtaining better school grades and results at national examinations, and boys scoring higher at standardized tests. In this paper, we provide a framework for better understanding and interpreting these d...

The epidemiology of cognitive development is an approach essentially based on large observational studies, which examines individual differences in cognitive abilities throughout childhood and their determinants. Although different in terms of methodology and main interests from developmental psychology, cognitive epidemiology offers complementary...

Inconsistencies across studies investigating subcortical correlates of autism spectrum disorder (ASD) may stem from small sample size, sample heterogeneity, and omitting or linearly adjusting for total brain volume (TBV). To properly adjust for TBV, brain allometry—the nonlinear scaling relationship between regional volumes and TBV—was considered w...

To properly adjust for total brain volume (TBV), brain allometry - the non-linear scaling relationship between regional volumes and TBV - was considered when examining subcortical volumetric differences between typically developing (TD) and Autistim Spectrum Disorder (ASD) individuals. Autism Brain Imaging Data Exchange I (N = 654) data was analyze...

Objectives To assess the association between prenatal exposure to monotherapy with the antiepileptic drugs (AEDs) most commonly used during pregnancy and the risk of various neurodevelopmental outcomes compared with lamotrigine. Design Nationwide population-based cohort study. Setting French national healthcare databases. Participants Children b...

The current study aimed at comparing the effect of three placements of the re-exposure episodes on memory retention (interpolated-small, interpolated-medium, postponed), depending on whether retrieval practice or re-reading was used, and on retention interval (one week vs one month).

Spaced retrieval practice consists of repetitions of the same retrieval event distributed through time. This learning strategy combines two “desirable difficulties”: retrieval practice and spacing effects. We carried out meta-analyses on 29 studies investigating the benefit of spacing out retrieval practice episodes on final retention.

In the present longitudinal study, we investigated the joint effect of early family factors and long-term vocabulary development on the structure of reading-related white matter pathways in adolescents. Seventy-nine children participated in this study. Family environment was measured via parental questionnaire between age 1 and age 3. From age 4 to...

Despite evidence for a difference in total brain volume between dyslexic and good readers, no previous neuroimaging study examined differences in allometric scaling (i.e. differences in the relationship between regional and total brain volumes) between dyslexic and good readers. The present study aims to fill this gap by testing differences in allo...

To determine whether the neural anomalies underlying developmental dyslexia are universal across languages or influenced by the writing system, we tested 10-year-old Chinese and French children, with or without dyslexia, in a cross-cultural fMRI paradigm. We compared their brain responses to words written in their known script, faces and houses whi...

Children with developmental coordination disorder also manifest difficulties in non-motor domains (attentional, emotional, behavioral and socialization skills). Longitudinal studies can help disentangle the complex relationships between the development of motor skills and other cognitive domains. This study aims to examine the contribution of early...

Compared with other learning strategies, retrieval practice seems to promote superior long-term retention. This has been found mostly in conditions where learners take tests after being exposed to learning content. However, a pre-testing effect has also been demonstrated, with promising results. This raises the question, for a given amount of time...

The number of older siblings a child has is negatively correlated with the child’s verbal skills, perhaps because of competition for parents’ attention. In the current study, we examined the role of siblings’ sex and age gap as moderating factors, reasoning that they affect older siblings’ tendency to compensate for reduced parental attention. We h...

The number of older siblings a child has is negatively correlated with their verbal skills, perhaps due to competition for parents’ attention. The current study examined the role of siblings’ sex and age gap as moderating factors, reasoning that they affect older siblings’ tendency to compensate for reduced parental attention. We hypothesized that...

This study investigated whether there is a co-occurrence between developmental dyslexia and congenital amusia in adults. First, a database of online musical tests on 18,000 participants was analysed. Self-reported dyslexic participants performed significantly lower on melodic skills than matched controls, suggesting a possible link between reading...

Developmental dyslexia (DD) is one of the most prevalent learning disorders, with high impact on school and psychosocial development and high comorbidity with conditions like attention-deficit hyperactivity disorder (ADHD), depression, and anxiety. DD is characterized by deficits in different cognitive skills, including word reading, spelling, rapi...

A number of studies have shown an abnormal connectivity of certain white matter pathways in developmental dyslexia, as well as correlations between these white matter pathways and behavioral deficits. However, whether developmental dyslexia presents broader white matter network connectivity disruption is currently unknown. The present study reconst...

The cover image, by Mengmeng Su et al., is based on the Paper Vocabulary growth rate from preschool to school‐age years is reflected in the connectivity of the arcuate fasciculus in 14‐year‐old children, DOI: 10.1111/desc.12647.

Neuroimaging studies investigating the neural correlates oflQ (or more specifically of high IQ) show that individuals with high IQ have, on average, greater brain activations in prefrontal and posterior parietal cortex, stronger functional and structural connectivity, and a larger brain. None of these neural characteristics seem specific to high IQ...

Developmental dyslexia (DD) is one of the most prevalent learning disorders among children and is characterized by deficits in different cognitive skills, including reading, spelling, short term memory and others. To help unravel the genetic basis of these skills, we conducted a Genome Wide Association Study (GWAS), including nine cohorts of readin...