Unveiling the Mysteries of Dyslexia—Lessons Learned from the Prospective Jyväskylä Longitudinal Study of Dyslexia

Abstract

This paper reviews the observations of the Jyväskylä Longitudinal Study of Dyslexia (JLD). The JLD is a prospective family risk study in which the development of children with familial risk for dyslexia (N = 108) due to parental dyslexia and controls without dyslexia risk (N = 92) were followed from birth to adulthood. The JLD revealed that the likelihood of at-risk children performing poorly in reading and spelling tasks was fourfold compared to the controls. Auditory insensitivity of newborns observed during the first week of life using brain event-related potentials (ERPs) was shown to be the first precursor of dyslexia. ERPs measured at six months of age related to phoneme length identification differentiated the family risk group from the control group and predicted reading speed until the age of 14 years. Early oral language skills, phonological processing skills, rapid automatized naming, and letter knowledge differentiated the groups from ages 2.5–3.5 years onwards and predicted dyslexia and reading development, including reading comprehension, until adolescence. The home environment, a child’s interest in reading, and task avoidance were not different in the risk group but were found to be additional predictors of reading development. Based on the JLD findings, preventive and intervention methods utilizing the association learning approach have been developed.

Development of Numeracy and Literacy Skills in Early Childhood—A Longitudinal Study on the Roles of Home Environment and Familial Risk for Reading and Math Difficulties

“…Letter knowledge was assessed with two tasks: in T1 and T2 with the VIIVI test (Torppa et al, 2006;Lohvansuu et al, 2021) and in T3 and T4 with the ARMI test (Lerkkanen et al, 2006). In the VIIVI letter naming task, the child was asked to name letters written in capitals and presented one at a time on their own page.…”

Pre-elementary Children With Imperfect Letter-Name Knowledge Are at Great Risk of Reading Difficulty in First Grade: One-Year Longitudinal Study in Japanese Hiragana

“…Since an empirically-determined goal of letter-naming ability is not necessarily part of the official curriculum for preschoolers (Piasta et al, 2012), the present findings and those of future studies must be considered in the development of policies for early education, especially for facilitating the identification of at-risk children. While letter-name knowledge may be the strongest predictor of reading development in any scripts, including the most transparent ones (e.g., Lohvansuu et al, 2021), cross-linguistic and cross-script differences in letternaming should be carefully considered upon the establishment of particular benchmarks to monitor children's early reading acquisition more effectively.…”

“…Fourth, a substantial influence of environmental and genetic factors, such socio-economic status (SES), home literacy environment, and familial background, on early reading development has been reported, even in transparent scripts (Strang and Piasta, 2016;Lohvansuu et al, 2021). Thus, lack of these measures also limits our conclusions, although letternaming in Hiragana could be less affected by environmental factors (Inomata et al, 2016).…”

How Visual Word Decoding and Context-Driven Auditory Semantic Integration Contribute to Reading Comprehension: A Test of Additive vs. Multiplicative Models

“…Thus, we hypothesized that the additive model might provide better predictive modeling results for our data. The findings of the present study will add to our understanding of the cognitive model of reading to further delineate the developmental trajectory of reading skills, which can provide the foundation to examine the brain mechanisms underlying the acquisition of normal reading skills in children as well as the disruptive neural correlates accompanying developmental dyslexia [39][40][41][42][43][44].…”