Lexical access in a bilingual speaker with dementia: Changes over time

In this article, we explore the naming skills of a bilingual English-Norwegian speaker diagnosed with Primary Progressive Aphasia, in each of his languages across three different speech contexts: confrontation naming, semi-spontaneous narrative (picture description), and conversation, and at two points in time: 12 and 30 months post diagnosis, respectively. The results are discussed in light of two main theories of lexical retrieval in healthy, elderly speakers: the Transmission Deficit Hypothesis and the Inhibitory Deficit Theory. Our data show that, consistent with the participant's premorbid use of and proficiency in the two languages, his performance in his L2 is lower than in his L1, but this difference diminishes as the disease progresses. This is the case across the three speech contexts; however, the difference is smaller in the narrative task, where his performance is very low in both languages already at the first measurement point. Despite his word finding problems, he is able to take active part in conversation, particularly in his L1 and more so at the first measurement point. In addition to the task effect, we find effects of word class, frequency, and cognateness on his naming skills. His performance seems to support the Transmission Deficit Hypothesis. By combining different tools and methods of analysis, we get a more comprehensive picture of the impact of the dementia on the speaker's languages from an intra-individual as well as an inter-individual perspective, which may be useful in research as well as in clinical practice.