The neural mechanism of writing Mitsuru Kawamura 1 , Machiko Kezuka 1 1Depart-ment of Neurology, Showa University School of Medicine Keyword: 失書 , 失語性失書 , 純粋失書 , 失読失書 , 文字言語 , 脳内メカニズム pp.755-762
Published Date 2003/10/10
DOI https://doi.org/10.11477/mf.1431100359
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 The first comprehensive theory on the neural mechanism of reading and writing was presented by Dejerine(1892)with schematic diagrams. A number of studies on the mechanism of writing have been carried out since then, although none seem to have surpassed the work of Dejerine and its comprehensive content.

 In the current article reviews of several types of agraphia were presented, and some comments are made from a new viewpoint. Then, carring out a different investigation which might develop Dejerine's schema of alexia and agraphia, a comprehensive hypothesis is proposed on the neural mechanism of writing.

 1.Aphasic agraphia

 1-1.Classical classification of aphasia:We presented the characteristics of agraphia of Broca type aphapsia, Wernicke type aphasia, conduction type aphasia, total aphasia, transcortical motor type aphasia, transcortical sensory type aphasia, mixed transcortical type aphasia, gogi aphasia, anomic aphasia and alexia with agraphia.

 1-2.Recent cognitive psychological classification of agraphia:We presented the characteristics of agraphia of phonological agraphia, lexical agraphia, semantic agraphia, deep dysgraphia.

 2.Pure agraphia:We presented the characteristics of agraphia with frontal lobe lesion, parietal lobe lesion, left hand agraphia.

 3.Atypical type of agraphia:We presented the characteristics of apraxic agraphia, spacial agraphia, constractional agraphia, pure agraphia and alexia with agraphia of musical notes, micrographia and hypergraphia.

 4.An expansion of the schemata of reading and writing by Dejerine:Based on of several types of disturbances of writing, we obtained a hypothesis on the neural mechanism of writing, and we proposed that there are two centers of writing in the left frontal lobe and in the left parietal lobe. We also introduced a recent cognitive psychological model of the writing system.

 5.Treatment:Finally, we presented the new rehabilitation techniques of agraphia by Kezuka.

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