Familial progressive aphasia: Insights into the nature and deterioration of single word processing

We present a longitudinal investigation of the language deficits of RB and CB, two brothers with primary progressive aphasia. Experiments 1 to 5 assessed word production in picture naming, naming with progressive phonemic cueing, reading, immediate and delayed repetition of single words, and repetition of two-word strings. Experiment 6 investigated receptive word processing using a picture-name judgement task with phonologically related, semantically related, and unrelated distractors. RB was less successful in naming than CB, and made most errors to semantically related distractors in the input task, whereas CB was more impaired than RB in repetition tasks and in detecting phonological distractors at input. The brothers are considered to have different processing deficits with reference to an interactive spreading activation model of speech production (Dell, 1986; Martin & Saffran, 1992).