Learning disabilities: A critical sketch on epidemiology

Abstract

The present review of epidemiological studies on the prevalence and stability of dyslexia and/or dyscalculia reveals that dyslexia is more frequently observed than dyscalculia. The prevalence of these learning disabilities decreases between early elementary school years and adulthood. Boys are more often identified as dyslexic than girls, whereas girls compared to boys more often demonstrate a co-occurrence of dyslexia and dyscalculia. The stability of learning disabilities seems to be a function of the tutoring practice. The prevalence estimate as well as the estimate of the stability of learning disabilities over time depends on the strength of the chosen cutoff points and the curricular validity of the preferred reading, spelling, and maths tests.