Common factors in Dyslexia and Dyscalculia: Is Phonological Awareness the key?

Abstract

Introduction – The effects of a weak phonological awareness (PA) concerning arithmetical fact retrieval are researched, in children with either dyslexia, dyscalculia or both, and compared to the effects of number sense (NS). We expect that the comorbidity of dyslexia and dyscalculia can be explained by PA. Method – 105 children from grade 4 to 6 have been tested on IQ, PA, numeracy and NS, and are divided in three groups: dyslexia, dyscalculia and comorbid. Results – Within the dyslexia group, numeracy correlates high with PA and medium with NS. PA explains 30.3% of variance in numeracy. Within the dyscalculia group, numeracy correlates high with NS, though is non-significant for PA. PA explains 1% in numeracy, whereas NS explains 31.2%. Within the comorbid group, numeracy correlates high with NS, though is non-significant for PA. PA explains 4.7% in numeracy, whereas NS explains 47.7%. Conclusion – No statistically significant effect for the influence PA might have on the arithmetical fact retrieval was found within the comorbid group. However, an effect was found for number sense as a possible overlap. The results are restricted by correlations of medium effect between IQ and PA within the dyscalculia and comorbid groups. Additionally, a gender effect for NS was found within the dyscalculia group. Moreover, our measurement of NS consists only of a number line representation.