COGNITIVE MECHANISMS FOR PROCESSING NONWORDS - EVIDENCE FROM ALZHEIMERS-DISEASE

Repetition and reading of various types of pronounceable nonwords (pse udowords) was examined in patients with probable Alzheimer's disease ( AD) and healthy elderly controls. Overall accuracy of performance was lower in AD patients compared to controls, but the two groups showed q ualitatively similar response patterns when reading different kinds of pseudowords aloud and when repeating pseudowords composed of familiar phonological forms. analogous to those in real English words. AD pati ents diverged in performance from controls, however, when repeating ps eudowords composed of phonologically unusual forms. These results supp ort two conclusions: (1) Aspects of phonological processing may become disrupted in AD patients in association with increasing dementia seve rity, while orthographic processing remains comparatively less impaire d. (2) The results are consistent with the view that the processing of pseudowords is achieved through the same system as real words, and fu rther show that the influence of prior language experience on the proc essing of novel linguistic forms occurs primarily at the level of phon ological, rather than orthographic processing. (C) 1998 Academic Press .