Visual word learning in adults with dyslexia

Abstract

We investigated word learning in university and college students with a diagnosis of dyslexia and in typically-reading controls. Participants read aloud short (4-letter) and longer (7-letter) nonwords as quickly as possible. The nonwords were repeated across 10 blocks, using a different random order in each block. Participants returned 7 days later and repeated the experiment. Accuracy was high in both groups. The dyslexics were substantially slower than the controls at reading the nonwords throughout the experiment. They also showed a larger length effect, indicating less effective decoding skills. Learning was demonstrated by faster reading of the nonwords across repeated presentations and by a reduction in the difference in reading speeds between shorter and longer nonwords. The dyslexics required more presentations of the nonwords before the length effect became non-significant, only showing convergence in reaction times between shorter and longer items in the second testing session where controls achieved convergence part-way through the first session. Participants also completed a psychological test battery assessing reading and spelling, vocabulary, phonological awareness, working memory, nonverbal ability and motor speed. The dyslexics performed at a similar level to the controls on nonverbal ability but significantly less well on all the other measures. Regression analyses found that decoding ability, measured as the speed of reading aloud nonwords when they were presented for the first time, was predicted by a composite of word reading and spelling scores (“literacy”). Word learning was assessed in terms of the improvement in naming speeds over 10 blocks of training. Learning was predicted by vocabulary and working memory scores, but not by literacy, phonological awareness, nonverbal ability or motor speed. The results show that young dyslexic adults have problems both in pronouncing novel words and in learning new written words.

Influence of context-sensitive rules on the formation of orthographic representations in Spanish dyslexic children

“…By contrast, dyslexic children continued to manifest a length effect in the sixth block (174 ms difference between short and long stimuli). These results are consistent with studies in other orthographic systems reporting that dyslexics have difficulties in storing the orthographic representations of words ( Hogaboam and Perfetti, 1978 ; Manis, 1985 ; Reitsma, 1989 ; Ehri and Saltmarsh, 1995 ; Martens and de Jong, 2008 ; Kwok and Ellis, 2014 ).They also confirm results recently obtained with Spanish dyslexic children using the same methodology ( Suárez-Coalla et al, 2014 ).…”

“…Finally, considering these results and those of other studies ( Kwok and Ellis, 2014 ; Suárez-Coalla et al, 2014 ), it will certainly be interesting to perform a study with a larger number of repetitions, and in different days, in order to know if dyslexic children are able to develop orthographic representations with more exposures ( Kwok and Ellis, 2014 ).…”

“…In fact, dyslexic children were not able to develop orthographic representations with six exposures and continue using sublexical reading for all new words. They probably need more exposures to achieve a direct reading, as suggested by Kwok and Ellis (2014) in their study with dyslexic adults. Overall, we conclude that dyslexic children show a selective learning deficit in forming orthographic representations, independent of whether stimuli contained consistent or not context-sensitive rules.…”

“…In a recent study, Kwok and Ellis (2014) used this length effect methodology to study the formation of orthographic representations in dyslexic adults. Participants had to read a list of 24 non-words, half short and half long, repeated across ten blocks.…”

Deaf children's non-verbal working memory is impacted by their language experience

“…Working memory is the capacity to encode, store, manipulate and recall information, and is essential for cognition (Baddeley and Hitch, 1974 ). As Hirshorn et al ( 2012 p. 85) write, “One would be hard pressed to name any higher level cognitive ability that does not foundationally depend on holding information in memory and being able to manipulate and integrate it with knowledge from long-term memory.” Not surprisingly, therefore, individual differences in working memory are associated with variation in such diverse activities as reasoning ability (Kyllonen and Christal, 1990 ), the acquisition of computer programming skills (Shute, 1991 ), and a whole set of activities that require language, such as reading comprehension (Daneman and Carpenter, 1980 ), novel word learning (Kwok and Ellis, 2014 ), syntactic processing (King and Just, 1991 ), second language learning (Kormos and Sáfár, 2008 ), acquiring an artificial language (Kapa and Colombo, 2014 ), and even adjusting to non-native speakers' lexical reference (Lev-Ari, 2015 ). Furthermore, individual differences in children's working memory are closely linked to their academic achievement (Alloway et al, 2005 ; Engel de Abreu et al, 2014 ).…”