Comorbidity in Dyslexia: Prevalence and Specific difficulties in Math Skills

Comorbidity in Dyslexia: Prevalence and Specific difficulties in Math Skills

First Author: Maria Rufina Pearson -- Universidad Catolica Argentina - JEL Aprendizaje
Additional authors/chairs: 
Josefina Pearson; Magdalena Magrane; Luciana Manuele
Keywords: Dyslexia, mathematical and reading literacy, Comorbidity, Mathematics, Writing
Abstract / Summary: 

Dyslexia is usually associated to other conditions. The goal of this study was to investigate comorbidity with specific mathematics difficulties, in a clinical sample diagnosed with dyslexia.
For that purpose we selected 98 children (ages 6 to 8) from an argentinean clinical sample (reading fluency under 25th percentile), and looked at their cognitive and achievement profile at the time of diagnosis. Children were tested on cognitive abilities with the WISC IV edition, the Woodcock Sandoval Muñoz achievement tests, and with Argentinean reading fluency (JEL) and math tests (JELMAT).
We found that 43% of the sample meet criteria for math difficulties with a cutoff equal or under the 30th percentile on the Woodcock Written Calculation and Problem Solving subtests. Children that meet criteria showed lower achievement on oral counting and verbal calculation and some operational skills as measured by the JELMAT test (oral counting t=2.049 p=.044; verbal calculation t=2.705 p=.008; and problem solving=2.704 p=.008). Achievement in written calculation, math fluency, and numerical concepts were similar in both groups, although 50% of each group performed under the standard level.
Verbal memory skills significantly differentiate children with math difficulties from those with only dyslexia (digits t=2.295 p=.024; information t=2.786 p=.007; phonological abilities t=3.859 p=.001).
Groups did not differ on reading fluency skills, however we found differences in Woodcock Muñoz reading comprehension (t=2.747 p=.007) and writing samples (t=2.488p=.015). From this study we reinforce the importance of having a full cognitive and achievement profile of children diagnosed with dyslexia, in order to be able to detect other difficulties that also need intervention.
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