Reduced Theta Sampling in Infants at Risk for Dyslexia across the Sensitive Period of Native Phoneme Learning

Abstract

Research on children and adults with developmental dyslexia—a specific difficulty in learning to read and spell—suggests that phonological deficits in dyslexia are linked to basic auditory deficits in temporal sampling. However, it remains undetermined whether such deficits are already present in infancy, especially during the sensitive period when the auditory system specializes in native phoneme perception. Because dyslexia is strongly hereditary, it is possible to examine infants for early predictors of the condition before detectable symptoms emerge. This study examines low-level auditory temporal sampling in infants at risk for dyslexia across the sensitive period of native phoneme learning. Using magnetoencephalography (MEG), we found deficient auditory sampling at theta in at-risk infants at both 6 and 12 months, indicating atypical auditory sampling at the syllabic rate in those infants across the sensitive period for native-language phoneme learning. This interpretation is supported by our additional finding that auditory sampling at theta predicted later vocabulary comprehension, nonlinguistic communication and the ability to combine words. Our results indicate a possible early marker of risk for dyslexia.

Experience-dependent effects of passive auditory exposure in infants impact theta phase synchrony and predict later language

“…2020 ; Bosseler et al. 2021 ; Mittag et al. 2022 ) and compared raw scores for these measures, converting them to z -scores for statistical analyses where appropriate.…”

“…2022 ) and in infants at familial risk for language and reading disorders ( Cantiani et al. 2019 ; Mittag et al. 2022 ).…”

Speech perception deficits and the effect of envelope-enhanced story listening combined with phonics intervention in pre-readers at risk for dyslexia

“…Infants then gradually develop a language-specific listening pattern, characterized by a decline of discriminating non-native and an improvement in distinguishing native-language phonetic contrasts (Werker and Tees, 1984;Kuhl et al, 2006). Behavioral and neural indications of altered phonemic representations have also already been observed in infants at family risk for dyslexia (Guttorm et al, 2001;Richardson et al, 2003;Van Leeuwen et al, 2007;Leppänen et al, 2010;Van Zuijen et al, 2012Mittag et al, 2022). These findings suggest that hampered phonological representations, possibly caused by disrupted neural entrainment, already exhibit in the very early stages of development and that the current auditory EE-intervention was simply delivered too late.…”