Timing anticipation in adults and children with Developmental Dyslexia: evidence of an inefficient mechanism

Elena Pagliarini,Lisa Scocchia,Daniela Sarti,Elisa Granocchio,Maria Teresa Guasti,Natale Stucchi

doi:10.1038/s41598-020-73435-z

Elena Pagliarini, Lisa Scocchia + Show 4 more

Open Access

https://doi.org/10.1038/s41598-020-73435-z

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Abstract

Developmental Dyslexia (DD) is a learning disorder characterized by specific difficulties in learning to read accurately and fluently, which has been generally explained in terms of phonological deficits. Recent research has shown that individuals with DD experience timing difficulties in the domains of language, music perception and motor control, probably due to impaired rhythmic perception, suggesting that timing deficit might be a key underlying factor to explain such a variety of difficulties. The present work presents two experiments aimed at assessing the anticipatory ability on a given rhythm of 9-year old Italian children and Italian adults with and without DD. Both adults and children with DD displayed a greater timing error and were more variable than controls in high predictable stimuli. No difference between participants with and without DD was found in the control condition, in which the uncertain timing of the beat did not permit the extraction of regularities. These results suggest that both children and adults with DD are unable to exploit temporal regularities to efficiently anticipate the next sensory event whereas control participants easily are. By showing that the anticipatory timing system of individuals with Developmental Dyslexia appears affected, this study adds another piece of evidence to the multifaceted reality of Developmental Dyslexia.

Highlights

Learning to read involves establishing connections between graphemes and phonemes
Adults with Developmental Dyslexia (DD) differed from their control in precision, that is in the variability of the inter tap interval (ITI), but did not differ in the ITI per s e66
Two s tudies[67,68] combining behavioral and neural measurements showed that the timing representation itself is deficient in dyslexics, ruling out the possibility that impairments in the domain of sensorimotor synchronization are due to an independent motor deficit

Summary

Introduction

Learning to read involves establishing connections between graphemes (printed words) and phonemes (sounds). The EEG results revealed differences in terms of preferred phase, due to children with DD having a preferred phase synchronizing ahead of the beat for both the tapping conditions and an auditory control condition These results suggest that prediction measured through synchronization is reduced in dyslexia because a predictable periodic template is not established, and —as the authors suggested—the problem may lie in perception and not production. The authors of this study found that the pre-stimulus delta phase angle (− 2 ms) of the target trials was predictive of the reaction time of the control group, but not of the dyslexic group, despite their equivalent behavioural performance Both the contingent negative variation amplitude and phase locking strength significantly predicted sensitivity to phonological awareness measures and reading measures, suggesting a functional link between neuronal anticipatory entrainment in the delta frequency range and reading performance. The novelty of our task lies in the possibility to directly test anticipation, based on the ability of extracting the regularity of the sequence, which is used to timely tap on the IB just after the WB—differently from a tapping task—where participants are required to give multiple serial responses by tapping in synchrony with a metronome and measures if participants are or not in synchrony

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