Agraphia selective for written spelling. An experimental case study

A 56-year-old right-handed man suffered left posterior parieto-temporal ischemia leading to mild aphasia, Gerstmann syndrome, and a novel variant of agraphia. This variant compromised his spelling by writing and manual sorting of letters more than his oral spelling. The dissociation was experimentally documented. It principally involved the intrusion of extraneous letters, independent of input modality. It did not generalized to numbers or an arbitrary code. Postoperatively the disability disappeared. It was concluded that the programs which translate letter choice into visual terms for purposes of written (as distinct from oral) spelling either originate or are transmitted in a distinct cerebral location. This location, which may be the left posterior parasagittal parietal area, can be selectively impaired by a focal lesion.