Improvements in reading and spelling skills after a phonological and morphological knowledge intervention in Greek children with spelling difficulties : a pilot study

In this study, we evaluated the effects of the online computer-based training program “Lexilogy-Greek” on the reading and spelling performance of young poor readers and spellers. The training is based on psycholinguistic principles that emphasize the importance of acquiring efficient phonological as well as morphological knowledge in remediating reading and spelling difficulties. Our sample consisted of fifteen 5th and 6th grade primary school children. Reading and spelling were tested at three points, with a no-intervention period and subsequently an intervention period in between these time points. We adopted a single group repeated measurement design and tested for intervention effects using repeated measures ANOVAs. The results revealed substantial treatment effects on spelling, word reading fluency and text reading fluency

HelexKids:a word frequency database for Greek and Cypriot primary school children

In this article, we introduce HelexKids, an online written-word database for Greek-speaking children in primary education (Grades 1 to 6). The database is organized on a grade-by-grade basis, and on a cumulative basis by combining Grade 1 with Grades 2 to 6. It provides values for Zipf, frequency per million, dispersion, estimated word frequency per million, standard word frequency, contextual diversity, orthographic Levenshtein distance, and lemma frequency. These values are derived from 116 textbooks used in primary education in Greece and Cyprus, producing a total of 68,692 different word types. HelexKids was developed to assist researchers in studying language development, educators in selecting age-appropriate items for teaching, as well as writers and authors of educational books for Greek/Cypriot children. The database is open access and can be searched online at www.helexkids.org

A Common Left Occipito-Temporal Dysfunction in Developmental Dyslexia and Acquired Letter-By-Letter Reading?

We used fMRI to examine functional brain abnormalities of German-speaking dyslexics who suffer from slow effortful reading but not from a reading accuracy problem. Similar to acquired cases of letter-by-letter reading, the developmental cases exhibited an abnormal strong effect of length (i.e., number of letters) on response time for words and pseudowords.Corresponding to lesions of left occipito-temporal (OT) regions in acquired cases, we found a dysfunction of this region in our developmental cases who failed to exhibit responsiveness of left OT regions to the length of words and pseudowords. This abnormality in the left OT cortex was accompanied by absent responsiveness to increased sublexical reading demands in phonological inferior frontal gyrus (IFG) regions. Interestingly, there was no abnormality in the left superior temporal cortex which--corresponding to the onological deficit explanation--is considered to be the prime locus of the reading difficulties of developmental dyslexia cases.The present functional imaging results suggest that developmental dyslexia similar to acquired letter-by-letter reading is due to a primary dysfunction of left OT regions

Vectorization-aware loop unrolling with seed forwarding

Loop unrolling is a widely adopted loop transformation, commonly used for enabling subsequent optimizations. Straight-line-code vectorization (SLP) is an optimization that benefits from unrolling. SLP converts isomorphic instruction sequences into vector code. Since unrolling generates repeatead isomorphic instruction sequences, it enables SLP to vectorize more code. However, most production compilers apply these optimizations independently and uncoordinated. Unrolling is commonly tuned to avoid code bloat, not maximizing the potential for vectorization, leading to missed vectorization opportunities. We are proposing VALU, a novel loop unrolling heuristic that takes vectorization into account when making unrolling decisions. Our heuristic is powered by an analysis that estimates the potential benefit of SLP vectorization for the unrolled version of the loop. Our heuristic then selects the unrolling factor that maximizes the utilization of the vector units. VALU also forwards the vectorizable code to SLP, allowing it to bypass its greedy search for vectorizable seed instructions, exposing more vectorization opportunities. Our evaluation on a production compiler shows that VALU uncovers many vectorization opportunities that were missed by the default loop unroller and vectorizers. This results in more vectorized code and significant performance speedups for 17 of the kernels of the TSVC benchmarks suite, reaching up to 2× speedup over the already highly optimized -O3. Our evaluation on full benchmarks from FreeBench and MiBench shows that VALU results in a geo-mean speedup of 1.06×

Semantic fluency difficulties in developmental dyslexia and developmental language disorder (DLD): poor semantic structure of the lexicon or slower retrieval processes?

Background: Children with dyslexia and/or developmental language disorder (hereafter children with DDLD) have been reported to retrieve fewer words than their typically developing (TD) peers in semantic fluency tasks. It is not known whether this retrieval difficulty can be attributed to the semantic structure of their lexicon being poor or, alternatively, to words being retrieved more slowly despite semantic structure being intact. / Aims: To test two theoretical models that could potentially account for retrieval difficulties in semantic fluency tasks, namely, the Poor Lexical–Semantic Structure Model and the Slow‐Retrieval Model. Both models predict that children with DDLD will retrieve fewer items compared with TD children. However, while the Poor Lexical–Semantic Structure Model predicts a less sophisticated network of semantic connections between words in the lexicon, as evidenced by smaller clusters of related items in children with DDLD, the Slow‐Retrieval Model predicts intact inter‐item associations in the lexicon, as evidenced by the two groups’ clusters being of a similar size. The groups’ semantic fluency performance was therefore compared. How semantic fluency performance related to children's language, literacy, and phonological skills was also investigated. / Methods & Procedures: A total of 66 children with DDLD aged 7–12 years and 83 TD children aged 6–12 years, all monolingual Greek speakers, were tested on semantic fluency, using the categories ‘animals’, ‘foods’ and ‘objects from around the house’. The numbers of correct and incorrect responses, clusters and switches, and the average cluster size were computed. Children were also assessed on non‐verbal IQ, language, literacy and phonological tasks. / Outcomes & Results: In both groups, productivity in semantic fluency tasks correlated strongly with the numbers of clusters and switches, but not with average cluster size. The DDLD group produced significantly fewer correct responses and fewer clusters compared with the TD group, but the two groups showed similar switching and average cluster size. Children's language, literacy and phonological skills significantly predicted the number of correct responses produced, beyond the significant effect of age. / Conclusions & Implications: We conclude that poorer semantic fluency performance in children with DDLD results not from a lexicon with poor semantic structure, but rather from slower retrieval processes from a lexicon with intact semantic structure. The underlying causes of slow lexical retrieval still need further investigation