Morphological alteration of temporal lobe gray matter in dyslexia: An MRI study

Author(s): Rumsey, J. M., Giedd, J. N., Schmitt, J. E., Patwardhan, A. J., Reiss, A. L.

Journal/Book: J Child Psychol Psychiat. 2000; 41: 40 West 20Th Street, New York, NY 10011-4211, USA. Cambridge Univ Press. 637-644.

Abstract: Functional imaging studies of developmental dyslexia have reported reduced task-related neural activity in the temporal and inferior parietal cortices. To examine the possible contribution of subtle anatomic deviations to these reductions, volumes were measured for the major lobes of the brain, the subcortical nuclei, cerebellum, and lateral ventricles on magnetic resonance imaging (MRI) scans from 16 right-handed dyslexic men, ages 18 to 40, and 14 matched controls, most of whom had previously undergone PET imaging. A specific decrease in tissue volume was localized to the temporal lobes and was particularly prominent on the left (p < .01). An analysis of tissue composition revealed that this reduction was primarily attributable to decreased gray matter within the left temporal lobe (p < .002). Further segmentation of the temporal lobe showed that this reduction was not confined to the superior temporal gyrus, the primary location of primary auditory cortex. Reductions of temporal lobe gray matter may reflect a regional decrease in neuronal number or neuropil, which in turn may result in reading impairment.

Note: Article Eliez S, Stanford Univ, Sch Med, Dept Psychiat & Behav Sci, 401 Quarry Rd, Stanford,CA 94305 USA

Keyword(s): brain development; brain imaging; cerebral lateralization; dyslexia; reading; temporal lobe; POSITRON EMISSION TOMOGRAPHY; DEVELOPMENTAL DYSLEXIA; PLANUM TEMPORALE; BRAIN; HANDEDNESS; ASYMMETRY; CHILDREN; CORTEX; PARCELLATION; ACTIVATION

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