OS_01. Dyslexia
Friday, September 30th, 2011 [10:50 - 11:50]
TALKS
OS_01.1 - Characterising attentional difficulties in children with reading disabilities
Serrano Chica, F. , Lupiáñez, J. , Soccini, A. & Defior, S.
University of Granada
Developmental dyslexia is a persistent reading disability usually associated with phonological deficits. Recent research has also found alterations in attentional processes associated to this disorder. However, these results are still controversial and highly dependent on the specific paradigm being used. This study aims to investigate dyslexic attentional difficulties by comparing different aspects of attention in children with and without reading disabilities. Participants are 72 children with reading disabilities (dyslexic and poor readers) compared to children with the same chronological age and younger children with the same reading level (reading level-matched design). A reduced version of the ANTI task was used to independently measure, within a single experimental session, three main attentional functions usually associated with the three attentional networks proposed by Posner: Alerting (Vigilance Network), Orienting (Posterior network) and Cognitive control (Anterior network). Results showed an overall slowing in responding in dyslexic children, together with larger interference (i.e., reduced cognitive control), as compared to the control groups. The observed attentional deficits are discussed in the context of current theories of dyslexia.
OS_01.2 - It’s about time: Revisiting rapid processing deficits in dyslexia
Casini, L. 1, 2 , Pech-Georgel, C. 4 , Burle, B. 1, 2 & Ziegler, J. 2, 3
1 Laboratoire de Neurobiologie de la Cognition.Université de Provence. Marseille, France
2 CNRS. France
3 Laboratoire de Psychologie Cognitive.Université de Provence. Marseille, France
4 Service de neurologie pédiatrique. CHU La Timone. Marseille, France
Developmental dyslexia is typically associated with a phonological deficit but the origin of this deficit is still a matter of debate. The purpose of the present study was to reexamine Tallal's rapid processing deficit theory according to which phonological deficits are caused by auditory temporal processing impairments. This was done by investigating whether such a temporal deficit could be found in speech as well as non-speech stimuli, and whether it would generalize to other sensory modalities. In particular, we studied how children with dyslexia dealt with temporal judgments in three different tasks: 1/ judgment of segmental duration in a speech perception task, 2/ duration judgment of non speech auditory stimuli, and 3/ duration judgment of visual stimuli. The results showed that children with dyslexia, compared to normally developing age-matched controls, presented deficits when processing segmental durations as well as the duration of non speech auditory or visual stimuli. These results are in agreement with Tallal's theory but are also consistent with a general and amodal temporal processing deficit. In the framework of cognitive theories of temporal processing, these data suggest a dysfunction of the “internal clock” in children with dyslexia.
OS_01.3 - Order or disorder? Impaired Hebb learning in dyslexia
Szmalec, A. 1 , Loncke, M. 1 , Page, M. 2 & Duyck, W. 1
1 Ghent University, Belgium
2 University of Hertfordshire, UK
The present study offers an integrative account which proposes that dyslexia and its various associated cognitive impairments reflect an underlying deficit in the long-term learning of serial-order information, here operationalized as Hebb repetition learning. In non-dyslexic individuals, improved immediate serial recall is typically observed when one particular sequence of items is repeated across an experimental session, a phenomenon known as the Hebb repetition effect. Starting from the critical observation that individuals with dyslexia seem to be selectively impaired in cognitive tasks that involve processing of serial order, the present study is the first to test and confirm the hypothesis that the Hebb repetition effect is affected in dyslexia, also in non-verbal modalities. We present a theoretical framework in which the Hebb repetition effect is assumed to be a laboratory analogue of naturalistic word learning, on the basis of which we argue that dyslexia is characterized by an impairment of serial-order learning that affects language learning and processing.