Prevalence and Gender Ratio of Dyslexia in Greek Adolescents and Its Association with Parental History and Brain Injury

Dyslexia is the most common and carefully studied of the learning disabilities in school-age children. It is characterized by a marked impairment in the development of reading skills, and affects a large number of people. The prevalence of dyslexia shows considerable cross-national variation. Additionally, a plethora of research studies have indicated that there are more boys than girls with reading difficulties. The aim of this study was to identify the frequency and gender ratio of dyslexia in a sample of Greek adolescents and their siblings. 598 secondary school students (Mean age 13.33, SD = 1.49) who attended mainstream public schools participated in this study. The prevalence of dyslexia in this study was estimated at 5.52%, a finding consistent with the data from other countries with “pure” orthographies. Statistical analysis revealed significant differences in the prevalence of dyslexia between gender (7.6% male, 3.8% female), which means that boys were twice as likely to be identified as dyslexic than their female peers. Additionally, statistically significant differences were observed between dyslexics who had a parent suffering from dyslexia (15.1%), compared to normal readers (1.8%), but no differences were observed between the two groups as for the frequency of brain injuries. Overall, our findings are in accordance with the results of previous national studies indicating the universal existence and the biological basis of this developmental disability.