[PS-1.1] The Bergen Longitudinal Dyslexia Study

Helland, T. & Morken, F.

Department of Biological and medical Psychology

Introduction. The aims of this study were to identify and follow up five-year-olds at risk of developmental dyslexia focusing on five areas: 1) pre-literate detection, 2) pre-literate training using a Bottom up (BU) and a Top down (TD) data-based training method, 3) neurocognitive development, 4) gender and heredity, 5) brain imaging (fMRI) at ages 6 (pre-literate phase), 8 and 12 (literate phases). Method. Parents and teachers of 109 five-year-old children (55 boys and 54 girls) from randomly selected districts in Norway answered a Risk Index questionnaire (RI-5) on soma, health, motor development, language development, need for special education, and heredity. 25 children were defined as at-risk. Together with 24 matched controls they were regularly assessed until they were twelve years old. The following is an overview of the main findings. Findings. 1) 13 children (11 at-risk, 2 controls) were identified as dyslexic when they were eleven years old); 2) data based training using both a TD and a BU training method showed significant effects; neurocognitive deficits seen in the dyslexia group before school age decreased by age; 3) the dyslexia group consisted of 5 boys and 8 girls with no statistical gender difference in literacy or IQ-scores; 4) for all boys (100%), but for only three (37.5%) of the girls, language problems and/or dyslexia in close biological family were reported; 5) Both pre- and post-literate fMRI showed evidence of diverging brain responses in the dyslexia group. Conclusions. We conclude that 1) the RI-5 questionnaire has predictive value, 2) early data based intervention combining a BU and a TD method has an effect, 3) neurocognitive deficits in dyslexia ameliorate by age, 4) dyslexia is equally distributed across genders, but with different gender etiologies, 5) diverging brain responses can be seen already in the pre-literate phase.