Redefiniendo la dislexia: explicando la variabilidad

The scientific effervescence that reigns around developmental dyslexia is explained by the difficult challenge that consists of ascribing this handicap to a single cause whilst multiple profiles of dyslexic patients can be observed. In this chapter, we start by presenting the main neuro-cognitive hypotheses that aim to explain dyslexia. We then review the multidimensional nature of dyslexia, and discuss the necessity of using a common diagnostic criteria to improve our understanding of its true nature. We then conclude by presenting promising work connecting cerebral endophenotypes and behavioral phenotypes highlighting the need for a multi-factorial rather than mono-theoretical account of developmental dyslexia.La efervescencia científica que reina en torno a la dislexia evolutiva se explica por el difícil desafío que implica atribuir esta dificultad a una causa simple al tiempo que se observan pacientes disléxicos con múltiples perfiles. En este capítulo, empezamos presentando la hipótesis neurocognitiva principal que persigue explicar la dislexia. Revisaremos la naturaleza multidimensional de la dislexia y discutiremos la necesidad de utilizar un criterio diagnóstico común para mejorar nuestra comprensión de su verdadera naturaleza. Concluiremos con la presentación de un trabajo prometedor que conecta endofenotipos cerebrales y fenotipos conductuales, resaltando la necesidad de un enfoque multifactorial más que monoteórico de la dislexia evolutiva

MEG data representing a gamma oscillatory response during the hold/release paradigm

The article presents magnetoencephalography (MEG) data from healthy participants while undergoing the Hold/Release paradigm. During the paradigm, participants visually perceived a sequence of two letter strings which either assembled into real words (Hold condition) or pseudowords (Release condition). If the first letter string was morphologically valid, they held their attention (and/or held the item in working-memory) to wait for the second string, whereas if it were invalid, they could release it, respectively. We present data on high-frequency neuronal oscillations of the Hold condition compared to the Release condition. Making this information publicly available could allow other researchers to perform analyses and contribute to understanding the cognitive processes such as language, mnemonic or attentional processes. Keywords: Hold/release paradigm, Magnetoencephalography, Gamma oscillations, Language, Working memory, Attentio

Impaired visual hand recognition in preoperative patients during brachial plexus anesthesia: importance of peripheral neural input for mental representation of the hand.

International audienceBACKGROUND: Perceptual illusions described in healthy subjects undergoing regional anesthesia (RA) are probably related to short-term plastic brain changes. We addressed whether performance on an implicit mental rotation task reflects these RA-induced changes in body schema brain representations. Studying these changes in healthy volunteers may shed light on normal function and the central mechanisms of pain. METHODS: Performance pattern was studied in upper limb-anesthetized subjects on a left/right hand judgment task, which is known to involve motor imagery processes relating to hand posture. Three conditions were used: control (i.e., absence of deafferentation), RA (i.e., deafferentation), and vision (i.e., deafferentated limb exposed to view). To limit potential bias such as order effect, the control state was recorded in a randomized manner. RESULTS: All subjects described perceptual illusions of their anesthetized limb. They were slower and less accurate on the task during RA compared with control. Response patterns were similar in all conditions, suggesting sensitivity of performance to arm/hand biomechanical constraints. Vision was associated with an increase in the proportion of correct responses and a reduction of the response times in hand judgment and was accompanied by disappearance of the lateralization of the underlying mental representations, which was identified during RA. CONCLUSIONS: These results suggest the following: (1) the right/left judgment task involves mental simulation of hand movements, (2) underlying mental representations and their neural substrates are subject to acute alterations after RA, and (3) the proprioceptive deficit induced by RA is influenced by the subject's ability to see the anesthetized limb

Strategic roadmap for an early diagnosis of Alzheimer's disease based on biomarkers

The diagnosis of Alzheimer's disease can be improved by the use of biological measures. Biomarkers of functional impairment, neuronal loss, and protein deposition that can be assessed by neuroimaging (ie, MRI and PET) or CSF analysis are increasingly being used to diagnose Alzheimer's disease in research studies and specialist clinical settings. However, the validation of the clinical usefulness of these biomarkers is incomplete, and that is hampering reimbursement for these tests by health insurance providers, their widespread clinical implementation, and improvements in quality of health care. We have developed a strategic five-phase roadmap to foster the clinical validation of biomarkers in Alzheimer's disease, adapted from the approach for cancer biomarkers. Sufficient evidence of analytical validity (phase 1 of a structured framework adapted from oncology) is available for all biomarkers, but their clinical validity (phases 2 and 3) and clinical utility (phases 4 and 5) are incomplete. To complete these phases, research priorities include the standardisation of the readout of these assays and thresholds for normality, the evaluation of their performance in detecting early disease, the development of diagnostic algorithms comprising combinations of biomarkers, and the development of clinical guidelines for the use of biomarkers in qualified memory clinics

Discovery of 42 genome-wide significant loci associated with dyslexia

Auteurs : 23andMe Research Team*, Quantitative Trait Working Group of the GenLang Consortium*International audienceReading 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 and 1,087,070 controls and identified 42 independent genome-wide significant loci: 15 in genes linked to cognitive ability/educational attainment, and 27 new and potentially more specific to dyslexia. We validated 23 loci (13 new) in independent cohorts of Chinese and European ancestry. Genetic etiology of dyslexia was similar between sexes, and genetic covariance with many traits was found, including ambidexterity, but n ot n eu ro an at omical measures of language-related circuitry. Dyslexia polygenic scores explained up to 6% of variance in reading traits, and might in future contribute to earlier identification and remediation of dyslexia. The ability to read is crucial for success at school and access to employment, information and health and social services, and is related to attained socioeconomic status 1. Dyslexia is a neurodevelopmental disorder characterized by severe reading difficulties, present in 5-17.5% of the population, depending on diagnostic criteria 2,3. It often involves impaired phonological processing (the decoding of sound units, or phonemes, within words) and frequently co-occurs with psychiatric and other developmental disorders 4 , especially attention-deficit hyperactivity disorde

Discovery of 42 genome-wide significant loci associated with dyslexia

AbstractReading 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 and 1,087,070 controls and identified 42 independent genome-wide significant loci: 15 in genes linked to cognitive ability/educational attainment, and 27 new and potentially more specific to dyslexia. We validated 23 loci (13 new) in independent cohorts of Chinese and European ancestry. Genetic etiology of dyslexia was similar between sexes, and genetic covariance with many traits was found, including ambidexterity, but not neuroanatomical measures of language-related circuitry. Dyslexia polygenic scores explained up to 6% of variance in reading traits, and might in future contribute to earlier identification and remediation of dyslexia.</jats:p

Optimization of adsorptive removal of α-toluic acid by CaO2 nanoparticles using response surface methodology

The present work addresses the optimization of process parameters for adsorptive removal of α-toluic acid by calcium peroxide (CaO2) nanoparticles using response surface methodology (RSM). CaO2 nanoparticles were synthesized by chemical precipitation method and confirmed by Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) analysis which shows the CaO2 nanoparticles size range of 5–15 nm. A series of batch adsorption experiments were performed using CaO2 nanoparticles to remove α-toluic acid from the aqueous solution. Further, an experimental based central composite design (CCD) was developed to study the interactive effect of CaO2 adsorbent dosage, initial concentration of α-toluic acid, and contact time on α-toluic acid removal efficiency (response) and optimization of the process. Analysis of variance (ANOVA) was performed to determine the significance of the individual and the interactive effects of variables on the response. The model predicted response showed a good agreement with the experimental response, and the coefficient of determination, (R2) was 0.92. Among the variables, the interactive effect of adsorbent dosage and the initial α-toluic acid concentration was found to have more influence on the response than the contact time. Numerical optimization of process by RSM showed the optimal adsorbent dosage, initial concentration of α-toluic acid, and contact time as 0.03 g, 7.06 g/L, and 34 min respectively. The predicted removal efficiency was 99.50%. The experiments performed under these conditions showed α-toluic acid removal efficiency up to 98.05%, which confirmed the adequacy of the model prediction