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Dyslexia ramus

Franck Ramus, Irene Altarelli, Katarzyna Jednoróg, Jingjing Zhao, Lou Scotto di Covella
Investigations into the neuroanatomical bases of developmental dyslexia have now spanned more than 40 years, starting with the post-mortem examination of a few individual brains in the 60s and 70s, and exploding in the 90s with the widespread use of MRI. The time is now ripe to reappraise the considerable amount of data gathered with MRI using different types of sequences (T1, diffusion, spectroscopy) and analysed using different methods (manual, voxel-based or surface-based morphometry, fractional anisotropy and tractography, multivariate analyses…)...
August 7, 2017: Neuroscience and Biobehavioral Reviews
Luba Daikhin, Ofri Raviv, Merav Ahissar
Purpose: The reading deficit for people with dyslexia is typically associated with linguistic, memory, and perceptual-discrimination difficulties, whose relation to reading impairment is disputed. We proposed that automatic detection and usage of serial sound regularities for individuals with dyslexia is impaired (anchoring deficit hypothesis), leading to the formation of less reliable sound predictions. Agus, Carrión-Castillo, Pressnitzer, and Ramus, (2014) reported seemingly contradictory evidence by showing similar performance by participants with and without dyslexia in a demanding auditory task that contained task-relevant regularities...
February 1, 2017: Journal of Speech, Language, and Hearing Research: JSLHR
Piotr Płoński, Wojciech Gradkowski, Irene Altarelli, Karla Monzalvo, Muna van Ermingen-Marbach, Marion Grande, Stefan Heim, Artur Marchewka, Piotr Bogorodzki, Franck Ramus, Katarzyna Jednoróg
Despite decades of research, the anatomical abnormalities associated with developmental dyslexia are still not fully described. Studies have focused on between-group comparisons in which different neuroanatomical measures were generally explored in isolation, disregarding potential interactions between regions and measures. Here, for the first time a multivariate classification approach was used to investigate grey matter disruptions in children with dyslexia in a large (N = 236) multisite sample. A variety of cortical morphological features, including volumetric (volume, thickness and area) and geometric (folding index and mean curvature) measures were taken into account and generalizability of classification was assessed with both 10-fold and leave-one-out cross validation (LOOCV) techniques...
October 6, 2016: Human Brain Mapping
Amanda Saksida, Stéphanie Iannuzzi, Caroline Bogliotti, Yves Chaix, Jean-François Démonet, Laure Bricout, Catherine Billard, Marie-Ange Nguyen-Morel, Marie-France Le Heuzey, Isabelle Soares-Boucaud, Florence George, Johannes C Ziegler, Franck Ramus
In this study, we concurrently investigated 3 possible causes of dyslexia-a phonological deficit, visual stress, and a reduced visual attention span-in a large population of 164 dyslexic and 118 control French children, aged between 8 and 13 years old. We found that most dyslexic children showed a phonological deficit, either in terms of response accuracy (92.1% of the sample), speed (84.8%), or both (79.3%). Deficits in visual attention span, as measured by partial report ability, affected 28.1% of dyslexic participants, all of which also showed a phonological deficit...
October 2016: Developmental Psychology
Jingjing Zhao, Michel Thiebaut de Schotten, Irene Altarelli, Jessica Dubois, Franck Ramus
This study examines the structural integrity and the hemispheric lateralization patterns of four major association fiber pathways in a group of French dyslexic children and age-matched controls (from 9 to 14 years), using high angular diffusion imaging combined with spherical deconvolution tractography. Compared with age-matched controls, dyslexic children show increased hindrance-modulated oriented anisotropy (HMOA) in the right superior longitudinal fasciculus (SLF). They also show a reduced leftward asymmetry of the inferior fronto-occipital fasciculus (IFOF) and an increased rightward asymmetry of the second branch of the SLF (SLF II)...
March 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Irene Altarelli, François Leroy, Karla Monzalvo, Joel Fluss, Catherine Billard, Ghislaine Dehaene-Lambertz, Albert M Galaburda, Franck Ramus
Among the various asymmetrical structures of the human brain, the planum temporale, an anatomical region associated with a variety of auditory and language-related processes, has received particular attention. While its surface area has been shown to be greater in the left hemisphere compared to the right in about two-thirds of the general population, altered patterns of asymmetry were revealed by post mortem analyses in individuals with developmental dyslexia. These findings have been inconsistently replicated in magnetic resonance imaging studies of this disorder...
December 2014: Human Brain Mapping
Franck Ramus
A new study reports that activations of superior temporal regions for speech are normal in dyslexia, although being less well connected to downstream frontal regions. These findings support the hypothesis of a deficit in the access to phonological representations rather than in the representations themselves.
June 2014: Trends in Cognitive Sciences
Trevor R Agus, Amaia Carrión-Castillo, Daniel Pressnitzer, Franck Ramus
PURPOSE: A phonological deficit is thought to affect most individuals with developmental dyslexia. The present study addresses whether the phonological deficit is caused by difficulties with perceptual learning of fine acoustic details. METHOD: A demanding test of nonverbal auditory memory, "noise learning," was administered to both adults with dyslexia and control adult participants. On each trial, listeners had to decide whether a stimulus was a 1-s noise token or 2 abutting presentations of the same 0...
June 1, 2014: Journal of Speech, Language, and Hearing Research: JSLHR
Jessica Becker, Darina Czamara, Tom S Scerri, Franck Ramus, Valéria Csépe, Joel B Talcott, John Stein, Andrew Morris, Kerstin U Ludwig, Per Hoffmann, Ferenc Honbolygó, Dénes Tóth, Fabien Fauchereau, Caroline Bogliotti, Stéphanie Iannuzzi, Yves Chaix, Sylviane Valdois, Catherine Billard, Florence George, Isabelle Soares-Boucaud, Christophe-Loïc Gérard, Sanne van der Mark, Enrico Schulz, Anniek Vaessen, Urs Maurer, Kaisa Lohvansuu, Heikki Lyytinen, Marco Zucchelli, Daniel Brandeis, Leo Blomert, Paavo H T Leppänen, Jennifer Bruder, Anthony P Monaco, Bertram Müller-Myhsok, Juha Kere, Karin Landerl, Markus M Nöthen, Gerd Schulte-Körne, Silvia Paracchini, Myriam Peyrard-Janvid, Johannes Schumacher
Dyslexia is one of the most common childhood disorders with a prevalence of around 5-10% in school-age children. Although an important genetic component is known to have a role in the aetiology of dyslexia, we are far from understanding the molecular mechanisms leading to the disorder. Several candidate genes have been implicated in dyslexia, including DYX1C1, DCDC2, KIAA0319, and the MRPL19/C2ORF3 locus, each with reports of both positive and no replications. We generated a European cross-linguistic sample of school-age children - the NeuroDys cohort - that includes more than 900 individuals with dyslexia, sampled with homogenous inclusion criteria across eight European countries, and a comparable number of controls...
May 2014: European Journal of Human Genetics: EJHG
Katia Lehongre, Benjamin Morillon, Anne-Lise Giraud, Franck Ramus
The aim of the present study was to explore auditory cortical oscillation properties in developmental dyslexia. We recorded cortical activity in 17 dyslexic participants and 15 matched controls using simultaneous EEG and fMRI during passive viewing of an audiovisual movie. We compared the distribution of brain oscillations in the delta, theta and gamma ranges over left and right auditory cortices. In controls, our results are consistent with the hypothesis that there is a dominance of gamma oscillations in the left hemisphere and a dominance of delta-theta oscillations in the right hemisphere...
2013: Frontiers in Human Neuroscience
Irene Altarelli, Karla Monzalvo, Stéphanie Iannuzzi, Joel Fluss, Catherine Billard, Franck Ramus, Ghislaine Dehaene-Lambertz
Developmental dyslexia is a learning disability that specifically affects reading acquisition. Cortical anomalies and gray matter volume differences in various temporal regions have been reported in dyslexic subjects compared with controls. However, consistency between studies is lacking. In the present experiments, we focused our structural analyses on the ventral occipitotemporal regions, defined by their functional response to visual categories. We applied a subject-by-subject functionally guided approach on a total of 76 participants (31 dyslexic children)...
July 3, 2013: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Franck Ramus, Chloe R Marshall, Stuart Rosen, Heather K J van der Lely
An on-going debate surrounds the relationship between specific language impairment and developmental dyslexia, in particular with respect to their phonological abilities. Are these distinct disorders? To what extent do they overlap? Which cognitive and linguistic profiles correspond to specific language impairment, dyslexia and comorbid cases? At least three different models have been proposed: the severity model, the additional deficit model and the component model. We address this issue by comparing children with specific language impairment only, those with dyslexia-only, those with specific language impairment and dyslexia and those with no impairment, using a broad test battery of language skills...
February 2013: Brain: a Journal of Neurology
Karin Landerl, Franck Ramus, Kristina Moll, Heikki Lyytinen, Paavo H T Leppänen, Kaisa Lohvansuu, Michael O'Donovan, Julie Williams, Jürgen Bartling, Jennifer Bruder, Sarah Kunze, Nina Neuhoff, Dénes Tóth, Ferenc Honbolygó, Valéria Csépe, Caroline Bogliotti, Stéphanie Iannuzzi, Yves Chaix, Jean-François Démonet, Emilie Longeras, Sylviane Valdois, Camille Chabernaud, Florence Delteil-Pinton, Catherine Billard, Florence George, Johannes C Ziegler, Isabelle Comte-Gervais, Isabelle Soares-Boucaud, Christophe-Loïc Gérard, Leo Blomert, Anniek Vaessen, Patty Gerretsen, Michel Ekkebus, Daniel Brandeis, Urs Maurer, Enrico Schulz, Sanne van der Mark, Bertram Müller-Myhsok, Gerd Schulte-Körne
BACKGROUND:  The relationship between phoneme awareness, rapid automatized naming (RAN), verbal short-term/working memory (ST/WM) and diagnostic category is investigated in control and dyslexic children, and the extent to which this depends on orthographic complexity. METHODS: General cognitive, phonological and literacy skills were tested in 1,138 control and 1,114 dyslexic children speaking six different languages spanning a large range of orthographic complexity (Finnish, Hungarian, German, Dutch, French, English)...
June 2013: Journal of Child Psychology and Psychiatry, and Allied Disciplines
Anne-Lise Giraud, Franck Ramus
Dyslexia is a polygenic developmental reading disorder characterized by an auditory/phonological deficit. Based on the latest genetic and neurophysiological studies, we propose a tentative model in which phonological deficits could arise from genetic anomalies of the cortical micro-architecture in the temporal lobe.
February 2013: Current Opinion in Neurobiology
Franck Ramus, Merav Ahissar
This paper provides a selective review of data on phonology, audition, vision, and learning abilities in developmental dyslexia, with a specific focus on patterns of normal alongside poor performance. Indeed we highlight the difficulties of interpreting poor performance, and we criticize theories of dyslexia that are exclusively suited to explaining poor performance, at the risk of overgeneralizing and predicting deficits in many more situations than are observed. We highlight a number of tasks and conditions where individuals with dyslexia seem to show perfectly normal performance, and we discuss the value of taking such data seriously into account and the difficulties of current theories to explain them...
2012: Cognitive Neuropsychology
Katia Lehongre, Franck Ramus, Nadège Villiermet, Denis Schwartz, Anne-Lise Giraud
It has recently been conjectured that dyslexia arises from abnormal auditory sampling. What sampling rate is altered and how it affects reading remains unclear. We hypothesized that by impairing phonemic parsing abnormal low-gamma sampling could yield phonemic representations of unusual format and disrupt phonological processing and verbal memory. Using magnetoencephalography and behavioral tests, we show in dyslexic subjects a reduced left-hemisphere bias for phonemic processing, reflected in less entrainment to ≈30 Hz acoustic modulations in left auditory cortex...
December 22, 2011: Neuron
Chloe R Marshall, Franck Ramus, Heather van der Lely
English speakers have to recognize, for example, that te[m] in te[m] pens is a form of ten, despite place assimilation of the nasal consonant. Children with dyslexia and specific language impairment (SLI) are commonly proposed to have a phonological deficit, and we investigate whether that deficit extends to place assimilation, as a way of probing phonological representations and phonological grammar. Children with SLI plus dyslexia, SLI only, and dyslexia only listened to sentences containing a target word in different assimilatory contexts-viable, unviable, and no change-and pressed a button to report hearing the target...
October 2011: Cognitive Neuropsychology
Efstathia Soroli, Gayaneh Szenkovits, Franck Ramus
This study investigates French dyslexic and control adult participants' ability to perceive and produce two different non-native contrasts (one segmental and one prosodic), across several conditions varying short-term memory load. For this purpose, we selected Korean plosive voicing (whose categories conflict with French ones) as the segmental contrast and lexical stress as the prosodic contrast (French does not use contrastive lexical stress). We also used a French (native) segmental contrast as a control...
November 2010: Dyslexia: the Journal of the British Dyslexia Association
Michelle Y Kibby, Judith M Kroese, Hillery Krebbs, Crystal E Hill, George W Hynd
Limited research has been conducted on the structure of the pars triangularis (PT) in dyslexia despite functional neuroimaging research finding it may play a role in phonological processing. Furthermore, research to date has not examined PT size in ADHD even though the right inferior frontal region has been implicated in the disorder. Hence, one of the purposes of this study was to examine the structure of the PT in dyslexia and ADHD. The other purposes included examining the PT in relation to overall expressive language ability and in relation to several specific linguistic functions given language functioning often is affected in both dyslexia and ADHD...
October 2009: Brain and Language
C R Marshall, S Harcourt-Brown, F Ramus, H K J van der Lely
BACKGROUND: Children with specific language impairment (SLI) and dyslexia are known to have impairments in various aspects of phonology, which have been claimed to cause their language and literacy impairments. However, 'phonology' encompasses a wide range of skills, and little is known about whether these phonological impairments extend to prosody. AIMS: To investigate certain prosodic abilities of children with SLI and/or dyslexia, to determine whether such children have prosodic impairments, whether they have the same pattern of impairments, and whether prosodic impairments are related to language and literacy deficits...
July 2009: International Journal of Language & Communication Disorders
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