Background
Many studies have showed that children with reading difficulties have deficits in both rapid automatized naming (RAN) and phonological skills (PS). The double-deficit hypothesis suggests that phonological and naming-speed deficits are two separable causes of reading problems. The main goal of our study was to investigate naming speed in Polish fourth grade children with dyslexia.
Material and Method
33 dyslexic children (10 girls and 23 boys) and 30 good readers participated in the study. They were given the Wechsler Intelligence Test for Children (WISC-R) and a battery of diagnostic tests for dyslexia for fourth-grade children, consisting of tests for single word reading, nonsense word reading, reading with word canceling, text comprehension, spelling on dictation, rapid automatic naming, phoneme elision, and phonological skills, as well as the Zetotest (a phonological memory test).
Results
The dyslexic children performed significantly more slowly than controls on the RAN tests, which suggests a generalized deficit in the speed of access to the mental lexicon. Significant correlations were found only between the RAN test and the text comprehension text. Among all the phonological measures applied in the study, slight but significant correlations were found only between phonological memory and speed naming. Dyslexic children with low speed naming abilities and high speed naming abilities showed no differences in phonological functions.
Conclusions
Our results confirm the double-deficit hypothesis of dyslexia.

Keywords: Phonetics, Poland, Mental Recall - physiology, Language Tests, Intelligence - physiology, Dyslexia - physiopathology, Child, Reaction Time, Reading