ABSTRACT
The underlying basis for developmental dyslexia is not well understood, but there is mounting evidence that disordered brain development might be at least partly responsible. Landmark studies identified cortical abnormalities in several cases consisting of neuronal ectopias and architectonic dysplasias, both in males and females with developmental dyslexia (Galaburda, Sherman, Rosen, Aboitiz, & Geschwind, 1985; Humphreys, Kaufmann, & Galaburda, 1990). These abnormalities are likely due to disordered neuronal migration of newly generated neurons to the cortex, and such abnormalities were present in far fewer numbers in neurologically normal individuals than in individuals with dyslexia (Kaufmann & Galaburda, 1989), suggesting a possible link between developmental dyslexia and neuronal migration (Njiokiktjien, 1994).
