eprintid: 3532
rev_number: 6
eprint_status: archive
userid: 6
dir: disk0/00/00/35/32
datestamp: 2016-09-12 11:28:13
lastmod: 2016-09-12 11:28:13
status_changed: 2016-09-12 11:28:13
type: article
metadata_visibility: show
creators_name: Chiarenza, Giuseppe A.
creators_name: Casarotto, Silvia
creators_name: Ricciardi, Emiliano
creators_name: Sani, Lorenzo
creators_name: Pietrini, Pietro
creators_id: 
creators_id: 
creators_id: emiliano.ricciardi@imtlucca.it
creators_id: 
creators_id: pietro.pietrini@imtlucca.it
title: Early dysfunction of perceptual processes in developmental dyslexia
ispublished: pub
subjects: RC0321
divisions: CSA
full_text_status: none
note: Special issue "Proceedings of the International Organization of Psychophysiology (I.O.P.) Budapest, Hungary September 1-4, 2010"
abstract: Objective: Single-letter reading is an early predictor of later reading success and identifies adult dyslexics [1]. This work investigates the differences between healthy and dyslexic children in brain activity during single-letter reading.

Methods: Event-related potentials (ERPs) were recorded from 45 healthy and 45 dyslexic children (age range 8–10 years) during self-paced letter recognition (SPLR), i.e. active reading aloud of letters presented at a self-determined pace. Standardized Low Resolution Electromagnetic Tomography (sLORETA) [2] was applied to individual ERPs and unpaired voxel-by-voxel t-test analysis (P < 0.05) was performed to compare the sLORETA maps between groups of subjects corresponding with the latency of the main grand average peaks.

Results: At middle latencies, dyslexics were characterized by a greater activation in the right middle-inferior frontal, insular and superior temporal regions and by impaired engagement of the left middle parietal lobe as compared to the healthy controls. At middle-long latencies, a significantly reduced activation in the left occipital gyrus was observed in dyslexic children compared to controls.

Conclusions: Distributed source imaging applied to ERPs describes the spatiotemporal dynamics of cerebral reading functions and allows inference regarding at which stage of the reading process the activation of the involved brain regions is disrupted in impaired readers. The existence of specific compensatory mechanisms may explain why dyslexic children who are characterized by impaired activation of left parietal and occipital regions show a significantly greater involvement of right temporal–parietal regions and premature engagement of right middle–inferior frontal regions as compared to controls.
date: 2010-09
publication: International Journal of Psychophysiology
volume: 77
number: 3
publisher: Elsevier
pagerange: 237-237
id_number: doi:10.1016/j.ijpsycho.2010.06.351
refereed: TRUE
issn: 0167-8760
official_url: http://doi.org/10.1016/j.ijpsycho.2010.06.351
citation:   Chiarenza, Giuseppe A. and Casarotto, Silvia and Ricciardi, Emiliano and Sani, Lorenzo and Pietrini, Pietro  Early dysfunction of perceptual processes in developmental dyslexia.  International Journal of Psychophysiology, 77 (3).  p. 237.  ISSN 0167-8760      (2010)