Lexical agraphia in Alzheimer's disease
S. Z. Rapcsak, S. A. Arthur, D. A. Bliklen and A. B. Rubens
Department of Neurology, University of Arizona Health Sciences Center, Tucson 85724.
We studied spelling in 11 patients with senile dementia of the Alzheimer
type (SDAT), and their performance was contrasted with that of normal
controls. A consistent and specific pattern of linguistic agraphia was
identified in the group with SDAT. Although patients with SDAT spelled
regular words and nonwords as well as controls, they performed
significantly worse when they spelled irregular words. These findings
indicated an impairment of the lexical spelling system, consistent with the
diagnosis of lexical agraphia. Our observations suggested a loss of word
representations from the orthographic lexicon in SDAT and/or an inability
to access these representations. However, phonological spelling
(phoneme-grapheme conversion) was largely spared.
