Processing proper nouns in aphasia: Evidence from assessment and therapy

Background: Dissociations between proper and common names following brain damage have frequently been reported (see Yasuda, Nakamura, & Beckman, 2000, for review) and suggest that these different word classes are processed by distinct mechanisms. The dissociations are often observed in people with relatively pure impairments, but might also be expected more generally in aphasia. There is the further possibility that the different vocabulary groups require different therapy approaches. Yet, to our knowledge, no study has explored whether treatments that are known to be successful with common nouns are also successful with proper nouns. Aims: This study had two main aims: to compare the comprehension and production of common and proper nouns in 20 people with aphasia; and to investigate whether semantic naming therapy is equally effective for common and proper nouns. Methods & Procedures: A total of 20 people with aphasia were tested in their ability to comprehend and produce matched sets of proper and common nouns. The stimuli comprised: 20 famous people, 20 famous places, 20 high-familiarity common nouns, and 20 low-familiarity common nouns. Participants were also tested with personally relevant proper names, such as the names of family members. In the second phase of the study 10 of the original participants were given semantic therapy for both common and proper nouns. Experimental measures explored effects on treated and untreated words. Outcomes & Results: Initial testing found that comprehension scores were generally high, with no word class effect. In production, proper nouns were significantly more difficult to name than the matched common nouns. However, this finding excluded personally relevant proper nouns, which were the most successfully named items. Results from the second phase showed that semantic therapy was equally effective in improving naming of both common and proper nouns. As in many previous studies, effects were almost entirely confined to treated items. Conclusions: Our findings suggest that proper nouns induce more naming failures in aphasia than common nouns. However, despite this, they seem equally amenable to therapy. Clinical and theoretical implications are discussed.