Phonolexical agraphia. Superimposition of acquired lexical agraphia on developmental phonological dysgraphia

Study of neuropsychological sequelae of a focal acquired brain lesion may bring out and help delineate the features of a compensated developmental language disorder and its anatomical substrate. A left-handed man with a history of phonological developmental dyslexia and dysgraphia learned in early adulthood to read and write using a lexical system. Following a small posterior right parietal infarct when aged 56 yrs he developed a severe agraphia displaying features of phonological dysgraphia with impaired segmentation and features of lexical agraphia. Writing was severely impaired for all classes of word and nonword stimuli but his errors did not resemble those attributable to a deficit in the system responsible for the short-term storage of the graphemic representation of a word (graphemic output buffer). These observations imply that an acquired lexical agraphia has been superimposed on his developmental phonological dysgraphia, resulting in a combined or 'phonolexical' agraphia.