Newborn brain responses measuring feature and change detection and predicting later language development in children with and without familial risk for dyslexia

Abstract

Lukemisen erityisvaikeuksia eli kehityksellistä dysleksiaa on noin 3-10 prosentilla suomalaisista koululaisista. Vaikeudet haittaavat eri tavoin heidän koulusuoriutumistaan ja vaikuttavat näin myös tulevaisuuden urasuunnitelmiin.Tomi Guttorm on väitöskirjatyössään verrannut vastasyntyneiden riskiryhmään kuuluvien ja muiden vauvojen kielellistä prosessointia. Hän toteaa, että jo muutaman päivän iässä aivoista tehtyjen havaintojen perusteella voidaan ennustaa riskivauvojen heikompia kielellisiä taitoja. Tulokset aivovasteiden ennustearvosta ovat tutkijan mielestä rohkaisevia kielellisten pulmien varhaisen tunnistamisen sekä tuki- ja kuntoutustoimien suunnittelun kannalta.

Event-related potentials (ERPs) measuring feature and change detection were studied from newborns with and without familial risk for dyslexia. The possibility of using newborn ERPs to predict later language development was also investigated. Results from a feature detection paradigm (/ba/, /da/, /ga/; presented equiprobably with interstimulus interval, ISI, of 4–7 seconds) showed hemispheric group differences at 540–630 ms (latency identified by principal component analysis, PCA), where the responses to /ga/ were clearly more positive and prolonged in the right hemisphere of the at-risk group. This response pattern in the right hemisphere at birth was related to significantly poorer receptive language skills across both groups at the age of 2.5 years. Similar ERP pattern in the left hemisphere was associated with poorer verbal memory skills at the age of 5 years. In the change detection paradigm (standard /kaa/ and deviant /ka/; presented in an oddball paradigm with 425 ms ISI), the ERPs at 290–320 ms (latency identified by PCA) predicted later skills only in the at-risk group. Larger positive responses to the deviant stimuli (change detection) in the left hemisphere predicted better receptive language skills at 2.5 years and verbal memory skills at 3.5 years, whereas a similar pattern in the right hemisphere was associated with poorer verbal memory skills at 5 years. Larger positive responses to the standard stimuli (general responsiveness) in the left hemisphere were associated with poorer receptive language skills at 2.5 and 3.5 years and verbal memory skills at 5 years. These results indicate that ERPs can be used to predict later language development in children with and without familial risk for dyslexia