When 'slime' becomes 'smile': Developmental letter position dyslexia in English

Saskia Kohnen*, Lyndsey Nickels, Anne Castles, Naama Friedmann, Genevieve McArthur

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We report the first three cases of selective developmental letter position dyslexia in English. Although the parents and teachers of the children were concerned about these children's reading, standard tests did not reveal their deficit. It was only when the appropriate target words were presented, in this case, migratable words, that their letter position dyslexia was detected. Whereas previous research has described cases with acquired and developmental forms of letter position dyslexia in Hebrew and Arabic readers, this is the first report of this type of reading disorder in English. The cardinal symptom of letter position dyslexia is the migration of letters within the word (reading slime as 'smile'; pirates as 'parties'). These migration errors occur in reading aloud as well as in tasks of silent reading. This study provides further evidence that migration errors emerge at the level of early visual-orthographic analysis, in the letter position encoding function. Alternative explanations for the occurrence of migration errors such as poor phonological processing or a deficit in the orthographic input lexicon are ruled out.

Original languageEnglish
Pages (from-to)3681-3692
Number of pages12
Issue number14
StatePublished - Dec 2012


FundersFunder number
Appalachian Regional Commission
National Health and Medical Research Council
Macquarie University
Centre of Excellence in Cognition and its Disorders, Australian Research CouncilCE110001021
Israel Science Foundation1296/06


    • Developmental dyslexia
    • Letter position coding
    • Lexical capture
    • Transposed letter nonwords
    • Transposed letter words


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