Slide Slam K16
Phoneme category and statistical rule violation detection is impaired in newborns at risk for dyslexia
Paula Virtala1, Kujala Teija1, Partanen Eino1, Hämäläinen Jarmo2, Winkler Istvan3; 1Cognitive Brain Research Unit, University of Helsinki, 2Jyväskylä Centre for Interdisciplinary Brain Research, University of Jyväskylä, 3Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
In early language acquisition, learning the native language phonemes is an important task. Mastering it requires grouping complex, acoustically variable sounds into categories by implicitly adopting feature conjunctions and temporal regularities from continuous speech, often referred to as statistical learning. Poor categorical phoneme processing, or more generally, implicit learning of sequential information may underlie developmental language disorder and dyslexia, two important neurodevelopmental disorders of language and literacy. In the present study, pre-attentive detection of phoneme category changes (vowel change in a sequence of vowels varying in pitch) and violations of feature rules (rising pitch in vowel pairs violated by occasional falling pitch; variable absolute pitch) were investigated in newborn infants with vs. without familial risk for dyslexia. The two rules pose two levels of difficulty in implicit statistical learning. In healthy infants, both of these rule violations elicited the mismatch response (MMR) of the electroencephalogram, reflecting that a) the violated rule has been detected and encoded by the newborn brain and b) a stimulus was found to deviate from the stored rule. In infants at risk for dyslexia, MMRs to phoneme category changes were diminished and mismatch responses to rule violations were absent. This suggests that implicit statistical learning of language-relevant rules, including phoneme categories, is impaired already at birth in infants at risk for dyslexia. These problems may then contribute to subsequent phonological deficits and to delayed language and literacy acquisition.