Brain Dysfunction in Developmental Dyslexia

Abstract

  Several neuroimaging studies on people with developmental dyslexia have reported hypoactivation in the left parietotemporal and left occipitotemporal regions, and hyperactivation in the left inferior frontal gyrus when reading alphabetic script. These atypical brain activities have been thought to reflect inefficient phonological processing, visual word recognition, and phonological output processing, respectively. However, whether this atypical brain activation pattern is language-universal still remains unclear, as Chinese-speaking people with dyslexia showed underactivation in the left middle frontal gyrus. Among the Japanese, poor readers showed an atypical brain activation pattern not only for reading but also for line drawing. Neuroimaging studies in Japan are limited, and further investigation is needed to better understand the neural substrates in Japanese-speaking people with developmental dyslexia.