Abstract of the day: Letter position dyslexia in Arabic: From form to position

May 15th, 2013

Naama Friedmann and Manar Haddad-Hanna (2012). Letter position dyslexia in Arabic: From form to position. Behavioural Neurology, 25, 93-103.

 

This study reports the reading of 4 Arabic-speaking individuals with letter position

dyslexia (LPD), and the effect of letter form on their reading errors. LPD is a peripheral dyslexia

caused by a selective deficit to letter position encoding in the orthographic-visual analyzer, which

results in migration of letters within words, primarily of middle letters. The Arabic orthography is

especially interesting for the study of LPD because Arabic letters have different forms in different

positions in the word. As a result, some letter position errors cause letter form change. We compared

the rate of letter migrations that change letter form with migrations that do not change letter form in

3 Arabic-speaking individuals with developmental LPD, and one bilingual Arabic and Hebrewspeaking

individual with acquired LPD. The results indicated that the participants made 85% letter

position errors in migratable words when the resulting word included the letters in the same form,

whereas migrations that caused letter form change almost never occurred. The error rate of the

Arabic-Hebrew bilingual reader was smaller in Arabic than in Hebrew, but when only words in

which migrations do not change letter form were counted, the rate was similar in Arabic and

Hebrew. Namely, whereas orthographies with multiple letter forms for each letter might seem more

difficult in some respects, these orthographies are in fact easier to read in some forms of dyslexia.

Thus, the diagnosis of LPD in Arabic should consider the effect of letter forms on migration errors,

and use stimuli that are migratable words that do not require letter-form change. The theoretical

implications for the reading model are that letter form is part of the information encoded in the

abstract letter identity, and thus affects further word recognition processes, and that there might be a

pre-lexical graphemic buffer in which the checking of orthographic well-formedness takes place.

 

For help with dyslexia on the Gold Coast and Tweed regions contact the Understanding Minds Dyslexia & Reading Difficulties Clinic .

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