title: Atypical perceptual narrowing in prematurely born infants is associated with compromised language acquisition at 2 years of age.
abstract: BACKGROUND
  Early auditory experiences are a prerequisite for speech and language acquisition. In healthy children, phoneme discrimination abilities improve for native and degrade for unfamiliar, socially irrelevant phoneme contrasts between 6 and 12 months of age as the brain tunes itself to, and specializes in the native spoken language. This process is known as perceptual narrowing, and has been found to predict normal native language acquisition. Prematurely born infants are known to be at an elevated risk for later language problems, but it remains unclear whether these problems relate to early perceptual narrowing. To address this question, we investigated early neurophysiological phoneme discrimination abilities and later language skills in prematurely born infants and in healthy, full-term infants.
  
  
  RESULTS
  Our follow-up study shows for the first time that perceptual narrowing for non-native phoneme contrasts found in the healthy controls at 12 months was not observed in very prematurely born infants. An electric mismatch response of the brain indicated that whereas full-term infants gradually lost their ability to discriminate non-native phonemes from 6 to 12 months of age, prematurely born infants kept on this ability. Language performance tested at the age of 2 years showed a significant delay in the prematurely born group. Moreover, those infants who did not become specialized in native phonemes at the age of one year, performed worse in the communicative language test (MacArthur Communicative Development Inventories) at the age of two years. Thus, decline in sensitivity to non-native phonemes served as a predictor for further language development.
  
  
  CONCLUSIONS
  Our data suggest that detrimental effects of prematurity on language skills are based on the low degree of specialization to native language early in development. Moreover, delayed or atypical perceptual narrowing was associated with slower language acquisition. The results hence suggest that language problems related to prematurity may partially originate already from this early tuning stage of language acquisition.
authors.affiliation: Faculty of Humanities, Logopedics, University of Oulu, Finland. eira.jansson-verkasalo@oulu.fi
authors.forename: Eira
authors.initials: E
authors.lastname: Jansson-Verkasalo
authors.forename: Timo
authors.initials: T
authors.lastname: Ruusuvirta
authors.forename: Minna
authors.initials: M
authors.lastname: Huotilainen
authors.forename: Paavo
authors.initials: P
authors.lastname: Alku
authors.forename: Elena
authors.initials: E
authors.lastname: Kushnerenko
authors.forename: Kalervo
authors.initials: K
authors.lastname: Suominen
authors.forename: Seppo
authors.initials: S
authors.lastname: Rytky
authors.forename: Mirja
authors.initials: M
authors.lastname: Luotonen
authors.forename: Tuula
authors.initials: T
authors.lastname: Kaukola
authors.forename: Uolevi
authors.initials: U
authors.lastname: Tolonen
authors.forename: Mikko
authors.initials: M
authors.lastname: Hallman
mesh_terms: D000161:Acoustic Stimulation; D000704:Analysis of Variance; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology; D002675:Child, Preschool; D004192:Discrimination, Psychological / Q000502:physiology*; D004569:Electroencephalography; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D007804:Language Development; D007807:Language Tests; D012815:Signal Processing, Computer-Assisted; D013060:Speech / Q000502:physiology*; D011795:Surveys and Questionnaires