An extensive pattern of atypical neural speech-sound discrimination in newborns at risk of dyslexia

Objective: Identifying early signs of developmental dyslexia, associated with deficient speech-sound processing, is paramount to establish early interventions. We aimed to find early speech-sound processing deficiencies in dyslexia, expecting diminished and atypically lateralized event-related potentials (ERP) and mismatch responses (MMR) in newborns at dyslexia risk.

Methods: ERPs were recorded to a pseudoword and its variants (vowel-duration, vowel-identity, and syllable-frequency changes) from 88 newborns at high or no familial risk. The response significance was tested, and group, laterality, and frontality effects were assessed with repeated-measures ANOVA.

Results: An early positive and right-lateralized ERP component was elicited by standard pseudowords in both groups, the response amplitude not differing between groups. Early negative MMRs were absent in the at-risk group, and MMRs to duration changes diminished compared to controls. MMRs to vowel changes had significant laterality x group interactions resulting from right-lateralized MMRs in controls.

Conclusions: The MMRs of high-risk infants were absent or diminished, and morphologically atypical, suggesting atypical neural speech-sound discrimination.

Significance: This atypical neural basis for speech discrimination may contribute to impaired language development, potentially leading to future reading problems. (C) 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.