Letter imagery deficits in a case of pure apraxic agraphia.

Pure apraxic agraphia is a condition in which motor writing is impaired but limb praxis and nonmotor writing (typing, anagram letters) are preserved. This condition is believed to result from disruption of a parietal lobe graphemic area which generates grapheme representations used to program motor-writing patterns. We report a single case of pure apraxic agraphia in which defective letter imagery was evident. Results of writing and imagery evaluations suggest that the graphemic area may be responsible for generating letter images. In this respect, clinical evaluation of letter imagery abilities in cases of apraxic agraphia may be useful in identifying subtypes of the disorder resulting in a better understanding of the neuropsychological process involved in writing.