Neurobiología y neurogenética de la dislexia

Wavelet packet analysis of EEG signals from dyslexic children with writing disability

This paper describes Wavelet Packet Analysis of EEG signal of dyslexic children with writing disability. Two activities were carried out during EEG recordings; relax and and writing letters. EEG signals were collected using biosignal gMobilab system and analysed using Wavelet Packet Decomposition to extract alpha and beta brainwave rhythm. Statistical data such as log energy entropy and standard deviation were used to compare the characteristic of EEG signals from dyslexic and normal children. Result showed that the dyslexic children consumed higher energy at left parietal lobe during writing activity especially those who write incorrectly. The alpha band shows higher log energy entropy for dyslexic children compare to normal children at most channel during relax.

A review of the neurobiological basis of dyslexia in the adult population

INTRODUCTION

Adult dyslexia affects about 4% of the population. However, studies on the neurobiological basis of dyslexia in adulthood are scarce compared to paediatric studies.

AIM

This review investigates the neurobiological basis of dyslexia in adulthood.

DEVELOPMENT

Using PsycINFO, a database of psychology abstracts, we identified 11 studies on genetics, 9 neurostructural studies, 13 neurofunctional studies and 24 neurophysiological studies. Results from the review show that dyslexia is highly heritable and displays polygenic transmission. Likewise, adult neuroimaging studies found structural, functional, and physiological changes in the parieto-occipital and occipito-temporal regions, and in the inferior frontal gyrus, in adults with dyslexia.

CONCLUSION

According to different studies, aetiology in cases of adult dyslexia is complex. We stress the need for neurobiological studies of dyslexia in languages with transparent spelling systems.

Dyslexia: A solution through Ayurveda evidences from Ayurveda for the management of dyslexia in children: A review

Dyslexia is one of the commonest learning disability. It is defined as a disorder where a child, in spite of all the classroom teaching, is not able to attain the language skills of reading, writing and spelling according to their level of intelligence. Dyslexia individuals often have difficulty in relating to the association between sound and their respective letters. Reversing or transposing the letters while writing is characteristic with letters such as b and d, P and q, etc., The prevalence among school children is reported as 9.87% and in the selected families, it is 28.32%. Dyslexia significantly interferes with academic achievement or activities of daily life and are not primarily due to sensory, motor or mentally handicaps. About 40% of dyslexic children and adolescents dropout of schools. According to Ayurveda, learning is a result of successive and complex interaction of Indriyas (cognitive and motor organs), Indriyartha (sense organs), Mana (psyche), Atma and Buddhi (intellect). Above all, the functioning of these factors is governed by Tridosha (vata, pitta and kapha) and Triguna (Sattva, Raja and Tama) in a specific coordination and balance Any disturbance in these Tridosha and Triguna will cause disordered functioning of Indriya, Mana and Buddhi leading to impaired learning or Dyslexia Ayurvedic drugs can help in the management of dyslexia by making these Tridosha and Triguna in well-balanced state and also by providing Medhya (intellect promoting) drugs to improve the learning ability in these children.

How many functional brains in developmental dyslexia? When the history of language delay makes the difference

BACKGROUND

Clinical manifestations of developmental dyslexia (DD) are greatly variable, suggesting complex underlying mechanisms. It was recently advanced that the characteristics of DD in Italian, a language with shallow orthography, are influenced by a positive history for language delay.

OBJECTIVE

We explored this hypothesis by studying in Italian individuals with DD (i) the brain representation of phonological processing with functional magnetic resonance imaging and (ii) the correlation between the patterns of activation and the presence/absence of previous language delay.

METHOD

Thirteen individuals with DD and 13 controls participated in the functional magnetic resonance imaging experiment consisting of a rhyme-generation task.

RESULTS

Individuals with DD showed a reduced activation of phonological processing areas of the left hemisphere, such as the middle frontal gyrus, the precuneus, and the inferior parietal lobule, and in particular the superior temporal gyrus. Furthermore, patients with a history of language delay had reduced activation in the left inferior and medial frontal gyrus, that was associated with worse reading and phonological accuracy than patients with normal language development.

CONCLUSIONS

Neurofunctional profiles of Italian individuals with DD are correlated to the history of language delay, suggesting that the relatively better behavioral profiles observed in individuals without a history of language delay are associated with a major activation of frontal networks normally involved in phonological working memory.