An Overview on Electrophysiological and Neuroimaging Findings in Dyslexia

Ronald  Hernández-Vásquez; Ulises Córdova García; Ana Maritza Boy Barreto; Milagritos Leonor  Rodriguez Rojas; Jacqueline  Ponce-Meza; Miguel  Saavedra-López

doi:10.18502/ijps.v18i4.13638

Ronald Hernández-Vásquez Universidad Privada Norbert Wiener, Lima, Perú.
Ulises Córdova García Universidad César Vallejo, Lima, Perú.
Ana Maritza Boy Barreto Universidad César Vallejo, Lima, Perú.
Milagritos Leonor Rodriguez Rojas Universidad César Vallejo, Lima, Perú.
Jacqueline Ponce-Meza Universidad Privada del Norte, Lima, Perú.
Miguel Saavedra-López Universidad Continental, Cusco, Perú.

DOI: https://doi.org/10.18502/ijps.v18i4.13638

Keywords: Brain Waves; Dyslexia; Electroencephalogram (EEG); Neuroimaging; Neuropathology

Abstract

Objective: Dyslexia is a prevalent neurodevelopmental condition that is characterized by inaccurate and slow word recognition. This article reviews neural correlates of dyslexia from both electrophysiological and neuroimaging studies.

Method: In this brief review, we provide electrophysiological and neuroimaging evidence from electroencephalogram (EEG) and magnetic resonance imaging (MRI) studies in dyslexia to understand functional and structural brain changes in this condition.

Results: In both electrophysiological and neuroimaging studies, the most frequently reported functional impairments in dyslexia include aberrant activation of the left hemisphere occipito-temporal cortex (OTC), temporo-parietal cortex (TPC), inferior frontal gyrus (IFG), and cerebellar areas. EEG studies have mostly highlighted the important role of lower frequency bands in dyslexia, especially theta waves. Furthermore, neuroimaging studies have suggested that dyslexia is related to functional and structural impairments in the left hemisphere regions associated with reading and language, including reduced grey matter volume in the left TPC, decreased white matter connectivity between reading networks, and hypo-activation of the left OTC and TPC. In addition, neural evidence from pre-reading children and infants at risk for dyslexia show that there are abnormalities in the dyslexic brain before learning to read begins.

Conclusion: Advances in comprehending the neural correlates of dyslexia could bring closer translation from basic to clinical neuroscience and effective rehabilitation for individuals who struggle to read. However, neuroscience still has great potential for clinical translation that requires further research.