Factors predicting success in picture naming in Alzheimer's disease and primary progressive aphasia.

The aim of the present study was to determine the predictive value of all important variables in the picture naming performance of 8 patients with probable Alzheimer's disease (AD) and 8 patients with primary progressive aphasia (PPA). The experimental investigation controlled for (i) visual complexity, (ii) name agreement on dominant response, (iii) age of acquisition, (iv) frequency, (v) word length, (vi) concept familiarity, and (vii) category membership. The results of the multiple regression analyses showed that age of acquisition and name agreement were significant for 10/16 subjects. Visual complexity, frequency, familiarity, and category were also significant for four patients respectively. Word length had no effect. These results are at variance with those of series of patients with AD (Gaillard et al., 1998) and with PPA (Lambon Ralph et al., 1998) where concept familiarity was found to be one of the most predictive factors of naming success.