Filippos M . Vlachos | UNIVERSITY OF THESSALY, GREECE (original) (raw)

Papers by Filippos M . Vlachos

Front. Behav. Neurosci. 18:1512892, 2025

Introduction: The aim of this study was to identify if children with dyslexia can be distinguishe... more Introduction: The aim of this study was to identify if children with dyslexia can be distinguished into discrete categories based on their domain deficits, indicating various neurocognitive subtypes of developmental dyslexia (DD).

Methods: The sample included 101 students in the 3rd, 4th, 5th, and 6th grades of primary school (mean age 11.15 years) with a diagnosis of dyslexia from a public center and Greek as their native language. The students underwent tests assessing a wide range of abilities, specifically phonological, memory, attention, processing speed abilities, motor, visual, and visual-motor skills.

Results: Cluster analysis revealed that children with dyslexia can be divided into three subtypes. The first subtype includes children identified based on their performance in tasks evaluating the phonological abilities, memory, attention, processing speed, along with visual-motor and visual skills. The second subtype comprises children identified based on their performance in memory abilities, motor, and visual-motor skills. The third subtype includes children identified solely based on their performance in the motor skills domain.

Discussion: In conclusion, our findings suggest that school-aged children with DD can be categorized into different subtypes with distinct neurocognitive characteristics. Furthermore, the results indicate that most children with dyslexia experience difficulties in more than one cognitive, sensory or motor domains, supporting contemporary models regarding the existence of multiple neurocognitive deficits in DD.

Hellenic Review of Special Education, 5, 79-98, 2017

The aim of this paper is to present the contemporary multiple deficit models for understanding de... more The aim of this paper is to present the contemporary multiple deficit models for understanding developmental dyslexia (DD), which replace the dominant theory of phonological deficit that attribute dyslexia to a single underlying cause, a deficit in phonological processing. We refer to the reasons that led to this transition from the single to multiple cognitive deficit models, presenting Pennington's multiple deficit model and the intergenerational multiple deficit model, as well as researches that support them. Recent researches have shown that dyslexia may be attributed to multiple neurocognitive deficits, is co-morbid with other disorders, and is characterized by a "continuum" in terms of the intensity it occurs. Characteristics of dyslexia appear to be transmitted predominantly genetically rather than environmentally from one generation to the next, while parents' reading skills are an important precursor of dyslexia in children. The review concludes that contemporary multiple deficit models provide a more comprehensive and complete interpretation of the causes and deficits that contribute to the occurrence of dyslexia.

Hellenic Review of Special Education, 5, 99-120, 2017

The aim of this longitudinal study was to examine whether specific skills developed during presch... more The aim of this longitudinal study was to examine whether specific skills developed during preschool years could predict the reading performance in children with low reading abilities in the first and second grade of primary school. In this longitudinal study 287 children (146 boys and 141 girls) participated, of whom we separated as children with low reading performance those that had a score 1.5 standard deviation below the average performance in total reading ability. 21 children (7.3% of the original sample) met the above criterion in the 1st grade and 22 children (7,6% of the original sample) in the 2nd grade. At the kindergarten, the phonological awareness (syllable segmentation, recognition of common initial phoneme, deletion of syllable and phoneme), the rapid automatized naming (RAN), the phonological short-term memory (digit span and repetition of nonwords), the auditory processing (discrimination of sets of sounds), the motor development (static balance, eye-movement co-ordination, coping shape) and the oral language (receptive and expressive vocabulary) were evaluated. Reading performance (accuracy, fluency and text comprehension) was evaluated in the 1st and 2nd grade of primary school. The results showed that phonological awareness and rapid automatized naming (RAN) predicted the low (total) reading performance in 1st grade, while phonological awareness was also the only predictor of reading accuracy and fluency. In the 2nd grade, the tests of motor development predict the low (total) reading performance, the rapid automatized naming predict reading accuracy and fluency and the coping shape predict text comprehension. Our results suggest that the utilization of such early evidence in the implementation of intervention programs during preschool and first school years could contribute to the prevention of possible problems in the reading performance of primary school children

Hellenic Review of Special Education, 5, 37–58, 2017

The aim of this study was to investigate possible deficits in phonological and visual-spatial mem... more The aim of this study was to investigate possible deficits in phonological and visual-spatial memory in children with developmental dyslexia. Participants were 14 children diagnosed with dyslexia and 14 typical developing children, who had been matched in pairs in terms of age and gender with the children of the first group. They were received seven phonological memory and three visual-spatial memory assessment tests. The results showed that the dyslexic students performed significantly lower than their typically developing peers in all phonological memory tests. Specifically, it was observed that children with dyslexia showed poorer performance in all phonological memory tests. Also, significantly poorer performance was observed in the visual-spatial short-term memory tests but no statistically significant differences were found in the long-term visual spatial memory tests. In conclusion, our findings are consistent with the findings of previous research showing that children with dyslexia have deficits in phonological memory and in short-term visual-spatial memory. The identified deficits in the above cognitive functions make it necessary to provide support to dyslexic children by their parents and teachers.

Paediatriki, 76, 20–25, 2013

Our knowledge concerning the biological basis of dyslexia has significantly increased during the ... more Our knowledge concerning the biological basis of dyslexia has significantly increased during the past few years, due to the ability to use sophisticated genetic analysis methods in order to identify genes implicated in the pathogenesis of dyslexia. The goal of this article is to provide a brief overview of recent research findings concerning the location and the investigation of the specific role of genes that relate to dyslexia. The studies so far have revealed 12 chromosomal loci and 13 “candidate” genes. They showed that none of the «dyslexia genes» is expressed exclusively within a particular cognitive area; on the contrary, they seem to influence basic processing of brain development and functioning. The correlation of the above findings offers the opportunity to a better understanding of the dyslexia heterogeneity, while it provides a framework to the interpretation of the comorbidity of dyslexia with other learning difficulties and developmental disabilities.

Hellenic Journal of Psychology, 7, 205–240, 2010

Dyslexia is a multi-symptomatic and heterogeneous disorder incorporating a wide variety of cognit... more Dyslexia is a multi-symptomatic and heterogeneous disorder incorporating a wide variety of cognitive difficulties, and which is neurobiological in origin. This article attempts to provide a brief overview of contemporary and often controversial theories and research findings on the causes of dyslexia. Our first aim was to give a picture of the extensive range of difficulties associated with what we call dyslexia, in order to understand its complexity and its possible causes. Our second and more important aim was to present an attempt for the convergence and synthesis of the causal theories on dyslexia based on the latest research findings. These findings indicate that a synthetic and complementary conception of the recent theoretical approaches to dyslexia could lead to a more satisfactory and more complete explanation of the symptoms and the causes of this disorder than the individual theories on their own.

Hellenic Review of Special Education, 5, 17–36, 2017

Developmental dyslexia is a disorder that occurs during child development, with early indications... more Developmental dyslexia is a disorder that occurs during child development, with early indications from pre-school age. Its symptoms are characterized by deficits in various cognitive domains as well as by behavioral problems that vary in intensity and quality. The purpose of the paper is to review research that confirms the heterogeneity in the cognitive profiles of dyslexic people and to validate in which cognitive areas they transpire. For each individual, either a single deficit, or multiple deficits may be responsible for these difficulties. Because of the combination of multiple deficits that poses serious problems to dyslexics, researchers tend to conclude that there exists considerable variability in the cognitive profiles of dyslexic individuals. Furthermore, extrinsic factors seem to affect the cognitive characteristics of dyslexics. Children with developmental dyslexia exhibit different characteristics, which could be attributed to the different structure of their language or to influences of the family environment.

Child & Adolescent Psychiatry, 2, 31-41, 2014

In this article we attempt a review of the literature on the genetic basis of “comorbidity” betwe... more In this article we attempt a review of the literature on the genetic basis of “comorbidity” between neurodevelopmental disorders (NDDs). Recent research confirms data of clinical experience that a child may frequently express symptoms of more than one disorder. This fact can create more difficulties in diagnosis and treatment. The question is whether these entities have distinct etiologies, thus justifying the use of the term “comorbidity”, or they merely belong to a continuum of brain dysfunctions with a common biological basis. Last decade research using analysis of genetic association along the whole human genome (Genome-Wide Association Studies) has identified several “candidate” genes predisposing to NDDs. This gene hunting is expected to explain the etiology and allow a better understanding of the biological pathways leading to NDDs. In addition, these studies proved that there is a certain genetic overlapping between them, as they share some regions of the genome so frequently that it could not be attributed to chance alone. In this article, we present a synthesis of research data about comorbidity among five of the most frequent NDDs and its genetic basis. We also briefly refer to the genes involved in these disorders and their impact in brain morphogenesis and function. The above genes are like to interact with other genes and with environmental factors to create a variety of phenotypes, even a variety of endophenotypes (variation in severity and expression) within the same disorder. These new data are possibly going to change the way the NDDs are diagnosed and classified and elucidate their relation to psychiatric diseases. Since neurodevelopmental disorders, despite their differences, may share some common genetic risk factors, we should consider them as a group of disorders with a common biological basis rather than comorbid ones.

DOAJ (DOAJ: Directory of Open Access Journals), Jun 1, 2022

European Journal of Special Needs Education, Apr 26, 2023

2017 IEEE Global Engineering Education Conference (EDUCON), 2017

Dyscalculia is a neurodevelopmental disorder that affects the ability of a child to learn arithme... more Dyscalculia is a neurodevelopmental disorder that affects the ability of a child to learn arithmetic. Dyscalculia appears despite normal intelligence, proper schooling, adequate environment, socioeconomic status and motivation. The first aim of the present research protocol was to construct a battery of tests that can be delivered by computer in order to screen children's arithmetic skills. Our second aim was to develop a web application screener for dyscalculia that assesses children aged from 8–11 years old and that, to the best of our knowledge, does not exist. The hypothesis of the present study was that Greek students that are already diagnosed by paper-and-pencil tests as dyscalculic, will present lower performance and higher time latencies in the tasks of the aforementioned web application screener. A total of sixty, right handed children (30 male and 30 female, age range 8–11 years old) participated in this study. The students with disorders in mathematics (N=30, 15 male and 15 female) had a statement of dyscalculia issued after assessment at a Centre of Diagnosis, Assessment and Support, as required by Greek Law. The comparison group (N=30) was formed by pupils who attended the same classes with dyscalculics, presented typical academic performance according to their teachers' ratings and had been matched for age and gender with the children with disorder in mathematics. Three tasks were used for evaluating children's arithmetic ability: a calculation task, a task that evaluated their skills in understanding mathematical terminology, and an arithmetic problem solving task. Statistical analysis revealed that children with dyscalculia had statistically significant lower mean scores of correct answers and larger time latencies in all tasks compared to their average peers that participated in the comparison group. In conclusion, it must be highlighted that the web application screener for dyscalculia used in this study was found to be a feasible instrument for first-pass screening services and referral.

Perceptual and Motor Skills, 1992

In this study we used the Rey-Osterrieth complex figure to examine the visuomotor organization of... more In this study we used the Rey-Osterrieth complex figure to examine the visuomotor organization of 514 boys and girls, aged 5.5 to 20.5 yr. All were left-handed as judged by the Edinburgh Handedness Inventory. Statistical evaluation showed significant differences in the visuomotor organization for boys and girls across the various age groups. Statistically significant differences also appeared between the two sexes at the age groups 7.5 to 8.5 and 8.5 to 9.5, with girls showing better organization than boys.

European Journal of Educational Research

The various intuitive reasoning types in many cases comprise the core of students’ misconceptions... more The various intuitive reasoning types in many cases comprise the core of students’ misconceptions about concepts, procedures and phenomena that pertain to natural sciences. Some researchers support the existence of a relatively closer connection between the right hemisphere and intuitive thought, mainly due to a notably closer relation of individual intuitive cognitive processes with specific right hemisphere regions. It has been suggested that individuals show a different preference in making use of each hemisphere’s cognitive capacity, a tendency which has been termed Hemisphericity or Hemisphere Preference. The purpose of the present study was to examine the association between hemispheric preference and students’ misconceptions. A correlational explanatory research approach was implemented involving 100 seventh grade students from a public secondary school. Participants completed a hemispheric preference test and a misconceptions documentation tool. The results revealed that the...

The Challenges of the Digital Transformation in Education, 2019

Dyslexia is the most common learning disability and it is characterized by a persistent failure t... more Dyslexia is the most common learning disability and it is characterized by a persistent failure to acquire reading skills despite normal intelligence, adequate cognitive abilities, conventional instruction and sociocultural opportunities. The main target of the present study was to extend our previous dyslexia screener web application by constructing and embedding new tasks. An extended battery of tests was implemented, which included sentence comprehension, auditory working memory, syllable composition and word explanation skills. Moreover, another aim of the study was to incorporate these tests into our existing web application. Statistical analysis revealed that dyslexic children presented lower correct responses (p < 0.01) and larger time latency (p < 0.05) in comparison to their average peers in all four tasks of the web application. Additionally, the main purpose of delivering a screening procedure via internet is that the users are doing something useful while perceiving that they are “playing a game”. The present study does not replace a seven task battery of tests with a four task one. One the contrary, it enriches an already used seven task battery with four more tests in order to design a more complete dyslexia web application screener.

Brain Sciences

According to DSM 5, generalized anxiety disorder (GAD) is characterized by excessive, uncontrolla... more According to DSM 5, generalized anxiety disorder (GAD) is characterized by excessive, uncontrollable worry about various topics that occupies the majority of the subject’s time for a period of at least six months. The aforementioned state causes distress and/or functional impairments. This paper presents the outcomes of a pilot study that evaluated the implementation of cognitive behavioral therapy (CBT) and CBT with an SSRIs intervention program. The participants comprised 16 children and adolescents with GAD (8 males and 8 females) matched with 16 typically developing peers (8 males and 8 females) aged from 10 to 16 years old (M = 12.56 SD = 2.18). Baseline assessment consisted of event related potentials (ERPs), which indicated that participants with GAD presented cognitive deficits in attention and memory, as they exhibited longer P300 latencies. Following treatment with the CBT program and/or medication, children and adolescents with GAD did not present statistically significan...

International Journal of Engineering Pedagogy (iJEP), 2017

Traditional definitions of Developmental Dyscalculia state that a child must substantially undera... more Traditional definitions of Developmental Dyscalculia state that a child must substantially underachieve on mathematical abilities tests relative to the level expected given age, education and intelligence. However, cognitive developmental neuropsychological studies nowadays suggest that not only core numerical but also cognitive skills of children with developmental dyscalculia present deficits. The main aim of the research protocol was to construct a battery of six tests that can be delivered by computer in order to screen children’s arithmetic and cognitive skills. The hypothesis of the study was that children that are already diagnosed by paper and pencil tests as dyscalculic will present lower scores and larger time latencies not only in arithmetical but also in executive function tasks. A total of 134 right handed children (74 male and 60 female, age range 8 – 12 years) participated in this study. The students with disorders in mathematics (N= 67, 37 male and 30 female age rang...