Proper and common names: a double dissociation

Proper name anomia and proper name sparing are unusual disorders characterized by a selective inability, or sparing, to retrieve proper names as opposed to common names. They may eventually demonstrate that these two categories of names are independently processed in the brain at the semantic or lexical/orthographic level. Yet, differences in patient assessment make comparison between cases difficult to interpret and raise alternative explanations to those dissociations, such as that they may be accounted for by the level of difficulty of test stimuli. We describe two individuals, of identical age, gender and cultural background, with a complementary pattern of impairment of name retrieval following a left hemisphere stroke. ACB had an aphasic disorder with impaired naming, sparing proper names, while JFJ had normal language abilities and semantic knowledge about people, but a marked anomia for people's names. Patients were studied using the same material, thus overcoming methodological constraints pointed to previous work. These cases provide evidence of a double dissociation between proper and common names at the lexical access level. In addition, JFJ had a normal ability to retrieve historical and religious names suggesting that either these names are less difficult to retrieve or that they may segregate within the proper name lexicon. Lesion of the left temporal pole was also dissociated. It was damaged in ACB but spared in JFJ, contradicting its crucial role in proper name processing.