Brain mechanisms in normal and dyslexic readers

Developmental dyslexics, individuals with an unexplained difficulty reading, have been shown to have deficits in phonological processing -- the awareness of the sound structure of words -- and, in some cases, a more fundamental deficit in rapid auditory processing. In addition, dyslexics show a disruption in white matter connectivity between posterior and frontal regions. These results give continued support for a neurobiological etiology of developmental dyslexia. However, more research will be required to determine the possible causal relationships between these neurobiological disruptions and dyslexia.

[1]  Curt von Euler,et al.  Temporal Information Processing in the Nervous System: Special Reference to Dyslexia and Dysphasia. Conference proceedings. New York City, New York, September 12-15, 1992. , 1993, Annals of the New York Academy of Sciences.

[2]  Steven G Zecker,et al.  Nonlinguistic perceptual deficits associated with reading and language disorders , 2000, Current Opinion in Neurobiology.

[3]  R. Woods,et al.  Abnormal processing of visual motion in dyslexia revealed by functional brain imaging , 1996, Nature.

[4]  A. Liberman,et al.  The Angular Gyrus in Developmental Dyslexia: Task-Specific Differences in Functional Connectivity Within Posterior Cortex , 2000, Psychological science.

[5]  Y. Samson,et al.  Lateralization of Speech and Auditory Temporal Processing , 1998, Journal of Cognitive Neuroscience.

[6]  J. Fletcher,et al.  Cerebral mechanisms involved in word reading in dyslexic children: a magnetic source imaging approach. , 2000, Cerebral cortex.

[7]  M. Merzenich,et al.  Cortical auditory signal processing in poor readers. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[8]  Jack M Fletcher,et al.  Brain activation profiles in dyslexic children during non-word reading: a magnetic source imaging study , 2000, Neuroscience Letters.

[9]  Richard B Ivry,et al.  A neural instantiation of the motor theory of speech perception Comment from Richard B. Ivry and Timothy C. Justus to Nicolson et al. , 2001, Trends in Neurosciences.

[10]  R. Poldrack,et al.  Disruption of the neural response to rapid acoustic stimuli in dyslexia: evidence from functional MRI. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[11]  J. Rumsey,et al.  Failure to activate the left temporoparietal cortex in dyslexia. An oxygen 15 positron emission tomographic study. , 1992, Archives of neurology.

[12]  Patricia A. McMullen,et al.  Converging methods for understanding reading and dyslexia , 1999 .

[13]  J. F. Stein,et al.  Magnocellular visual function and children's single word reading , 1998, Vision Research.

[14]  R. Poldrack,et al.  Microstructure of Temporo-Parietal White Matter as a Basis for Reading Ability Evidence from Diffusion Tensor Magnetic Resonance Imaging , 2000, Neuron.

[15]  M. Livingstone,et al.  Physiological and anatomical evidence for a magnocellular defect in developmental dyslexia. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[16]  A. Liberman,et al.  Functional disruption in the organization of the brain for reading in dyslexia. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[17]  E L Grigorenko,et al.  Developmental dyslexia: an update on genes, brains, and environments. , 2001, Journal of child psychology and psychiatry, and allied disciplines.

[18]  P. Dean,et al.  Developmental dyslexia: the cerebellar deficit hypothesis , 2001, Trends in Neurosciences.

[19]  Richard S. J. Frackowiak,et al.  Is developmental dyslexia a disconnection syndrome? Evidence from PET scanning. , 1996, Brain : a journal of neurology.

[20]  T. Carrell,et al.  Auditory Neurophysiologic Responses and Discrimination Deficits in Children with Learning Problems , 1996, Science.

[21]  Catherine E. Snow,et al.  Preventing reading difficulties in young children , 1998 .

[22]  Steven L. Miller,et al.  Temporal Processing Deficits of Language-Learning Impaired Children Ameliorated by Training , 1996, Science.

[23]  U. Frith,et al.  Explicit and implicit processing of words and pseudowords by adult developmental dyslexics: A search for Wernicke's Wortschatz? , 1999, Brain : a journal of neurology.

[24]  G. C. Orden,et al.  Phonological processing skills and deficits in adult dyslexics. , 1990, Child development.

[25]  J. Stein,et al.  The magnocellular theory of developmental dyslexia. , 2001, Dyslexia.

[26]  J. Desmond,et al.  Functional Specialization for Semantic and Phonological Processing in the Left Inferior Prefrontal Cortex , 1999, NeuroImage.

[27]  F. Ramus.  Dyslexia: Talk of two theories , 2001, Nature.

[28]  J. Maisog,et al.  A positron emission tomographic study of impaired word recognition and phonological processing in dyslexic men. , 1997, Archives of neurology.

[29]  P. Tallal,et al.  Developmental dysphasia: Relation between acoustic processing deficits and verbal processing , 1980, Neuropsychologia.

[30]  M. Habib,et al.  The neurological basis of developmental dyslexia: an overview and working hypothesis. , 2000, Brain : a journal of neurology.

[31]  N. Geschwind,et al.  Developmental dyslexia: Four consecutive patients with cortical anomalies , 1985, Annals of neurology.

[32]  D. Heeger,et al.  Brain activity in visual cortex predicts individual differences in reading performance. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[33]  R. Poldrack,et al.  Disrupted neural responses to phonological and orthographic processing in dyslexic children: an fMRI study , 2001, Neuroreport.

[34]  F. Fazio,et al.  Dyslexia: Cultural Diversity and Biological Unity , 2001, Science.

[35]  B. Horwitz,et al.  Functional connectivity of the angular gyrus in normal reading and dyslexia. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[36]  P. Tallal,et al.  Neurobiological Basis of Speech: A Case for the Preeminence of Temporal Processing , 1993, Annals of the New York Academy of Sciences.

[37]  P. Tallal.  Auditory temporal perception, phonics, and reading disabilities in children , 1980, Brain and Language.

[38]  T. Zeffiro,et al.  The cerebellum and dyslexia: perpetrator or innocent bystander? Comment from Thomas Zeffiro and Guinevere Eden to Nicolson et al. , 2001, Trends in Neurosciences.

[39]  D. Badcock,et al.  Specific reading disability: differences in contrast sensitivity as a function of spatial frequency. , 1980, Science.

[40]  Steven L. Miller,et al.  Language Comprehension in Language-Learning Impaired Children Improved with Acoustically Modified Speech , 1996, Science.