Dyslexia: Cultural Diversity and Biological Unity

• Published in: Science (American Association for the Advancement of Science) 2001-03, Vol.291 (5511), p.2165-2167
• Main Authors: Paulesu, E., J.-F. Démonet, Fazio, F., McCrory, E., Chanoine, V., Brunswick, N., Cappa, S. F., Cossu, G., Habib, M., Frith, C. D., Frith, U.
• Format: Article
• Language: English
• Subjects: Adult; Adults; Alphabets; Analysis; Articulation disorders; Behavioral psychophysiology; Beliefs; Biological and medical sciences; Brain; Brain - blood supply; Brain - diagnostic imaging; Brain - physiopathology; Brain Hemisphere Functions; Cerebral hemispheres; Cognitive science; Cross-Cultural Comparison; Cultural Pluralism; Culture; Dyslexia; Dyslexia - etiology; Dyslexia - physiopathology; English language; France; Fundamental and applied biological sciences. Psychology; Genetics; Hormones and behavior; Humans; Intelligence Quotient; Intelligence Tests; Italy; Language; Male; Matched-Pair Analysis; Memory; neurodevelopmental disorders; Neurology; Occipital Lobe - blood supply; Occipital Lobe - diagnostic imaging; Occipital Lobe - physiopathology; Orthographies; Perceptual Impairments; Positron emission tomography; Printed Materials; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Reading; Reading Difficulties; Reading Instruction; Reading Rate; Reading Skills; Reading Tests; Regional Blood Flow; Romance Languages; Screening Tests; Short Term Memory; Speed reading; Spelling; Stem cells; temporal gyrus; Temporal Lobe - blood supply; Temporal Lobe - diagnostic imaging; Temporal Lobe - physiopathology; Tomography; Tomography, Emission-Computed; United Kingdom; Wechsler scales; Word Recognition
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1057179

The recognition of dyslexia as a neurodevelopmental disorder has been hampered by the belief that it is not a specific diagnostic entity because it has variable and culture-specific manifestations. In line with this belief, we found that Italian dyslexics, using a shallow orthography which facilitates reading, performed better on reading tasks than did English and French dyslexics. However, all dyslexics were equally impaired relative to their controls on reading and phonological tasks. Positron emission tomography scans during explicit and implicit reading showed the same reduced activity in a region of the left hemisphere in dyslexics from all three countries, with the maximum peak in the middle temporal gyrus and additional peaks in the inferior and superior temporal gyri and middle occipital gyrus. We conclude that there is a universal neurocognitive basis for dyslexia and that differences in reading performance among dyslexics of different countries are due to different orthographies.