First Funding Phase
RAVEN; Differential Diagnostic Relevance of Working Memory for Children with Learning DisordersPublications
The research project RABE (English: RAVEN; Differential Diagnostic Relevance of Working Memory for Children with Learning Disorders) examined the cognitive causes of learning disorders (LDs) with a special focus on working memory (WM). Among the learning disorders examined were the specific reading disorder, the specific spelling disorder, the disorder of arithmetical skills, and the mixed disorder of scholastic skills.
The objective of the RAVEN study was to explore the differential diagnostic relevance of working memory for children with LD. Of further interest was to investigate interindividual differences in WM development. For instance, the following research questions were addressed:
Do children with various learning disorders exhibit different WM deficits?
How does WM develop in children with LD?
Are there any systematic differences in the development of WM between children who overcome their LD and those whose learning problems persist?
RAVEN is a multicenter study for which data collection was carried out in three federal states of Germany (Bremen, Hesse, and Lower Saxony). Of the 465 children who participated in this longitudinal study, 365 children exhibited learning difficulties in at least one academic domain (i.e., reading, spelling, and/or mathematics), while the remaining 100 children showed no learning problems and therefore served as a control group. Approximately half of the children with low achievement scores showed an additional IQ-achievement discrepancy according to ICD-10. The children were followed longitudinally from the beginning of third grade to the end of fifth grade: Once a year, their school achievement was tested as well as their WM functioning and additional cognitive factors. It was thus possible to examine the developmental interplay between WM and school achievement in children with LD.
The RAVEN study examined the prevalence and comorbidity of LD as well as issues relating to differential diagnostics:
On the prevalence of LD in mid-primary school 
We were interested in the prevalence rates of LD in mid-primary school. To this end, 2195 children in second and third grade completed standardized achievement tests for reading, spelling, and mathematics as well as a measure of nonverbal IQ. The results showed that 23.3 % of all children scored below average (T < 40) in at least one academic domain despite unimpaired intellectual ability (IQ ≥ 85). Of these, 13.3% also met the IQ-achievement discrepancy criterion of ICD-10. As regards the different LD subtypes, prevalence rates were highest for specific spelling disorder (F81.1; 4%) and lowest for the mixed disorder of scholastic skills (F81.3; 2%).
On the comorbidity of learning difficulties and ADHD symptoms 
The RAVEN study provided data on the comorbidity rates of specific learning difficulties and ADHD symptoms. Our results showed that only 5% of the control group as well as of the group with mathematical difficulties fulfilled the criteria of any one of the ADHD subtypes outlined in DSM-IV. By contrast, more than 20% of the children with learning difficulties in reading and/or spelling exhibited ADHD symptoms. Boys in the control group had a 1.5 times higher risk ratio for ADHD symptoms than girls, whereas boys with learning difficulties even showed a 2 to 6 times higher risk ratio.
Learning disorders in reading versus spelling , 
One objective of the RAVEN study was to investigate whether various learning disorders are associated with different WM profiles. With respect to learning disorders in reading versus spelling, our study revealed that children with reading disorder exhibited little impairments in the phonological loop, but marked impairments in the central executive. Children with spelling disorder showed severe deficits in the phonological loop but not in the other WM subcomponents. Those results suggest that it is important to take both reading and spelling into account when investigating the cognitive underpinnings of literacy difficulties in transparent orthographies. We also examined whether WM in children with poor literacy skills differs as a function of IQ-achievement discrepancy: Overall, largely similar WM profiles for children with poor reading and/or spelling skills were found regardless of whether they showed an IQ-achievement discrepancy or not.
Learning disorders in mathematics 
Previous studies on WM functioning in children with poor mathematical skills have produced heterogeneous results. The RAVEN study examined whether this heterogeneity can be attributed to the fact that comorbid reading and spelling difficulties as well as the IQ-achievement discrepancy have often not been taken into account when testing WM in children with poor mathematical skills. Our results showed that not fulfilling the IQ-achievement discrepancy was associated with poor visual WM, whereas comorbid reading and spelling difficulties were associated with poor central executive functioning in children fulfilling the IQ-achievement discrepancy. Overall, our results suggest that the IQ-achievement discrepancy as well as comorbid reading and spelling difficulties should be considered when investigating WM in children with poor mathematical skills.
The academic self-concept of children with LD 
Several studies converge on the view that children with learning difficulties have a lower academic self-concept than children without LD. However, whether the influence of specific learning difficulties on academic self-concept is domain-specific or domain-general is still at issue. In this regard, the RAVEN study revealed that children with LD showed a lower self-concept only in those academic domains in which they were low achieving. This result is in line with the domain specificity hypothesis. Furthermore, children’s self-concept in spelling and mathematics decreased significantly in the course of a school year. Overall, the children showed a sophisticated self-perception of their individual strengths and weaknesses at the end of primary school.