DETERMINING THE IMPACT OF AUTOBIOGRAPHICAL EXPERIENCE ON MEANING - NEW INSIGHTS FROM INVESTIGATING SPORTS-RELATED VOCABULARY AND KNOWLEDGE IN 2 CASES WITH SEMANTIC DEMENTIA

Snowden, Griffiths, and Neary (1994, 1995) have proposed that autobiog raphical experience helps to maintain the integrity of semantic memory in patients with semantic dementia. We investigated this hypothesis b y testing knowledge related to golf and bowls in two case studies. If Snowden and colleagues' hypothesis is correct, our two patients should have better semantic knowledge for the sport that they regularly expe rience, compared with knowledge of other sports. In keeping with Snowd en et al's hypothesis, we found that autobiographical experience influ enced the ability of the patients to match up a surname with a first n ame: The names of personally and currently relevant golf/bowls partner s were more likely to be matched correctly than such personally releva nt names from the past, or the names of famous sports celebrities. Unl ike Snowden et al., however, we found that knowledge of people, in all categories, was severely impoverished and that any semantic informati on was produced as part of an autobiographical memory. Likewise, detai led study of each patient's understanding of their favourite sport rev ealed no significant effect of autobiographical experience on true sem antic knowledge. We propose that the ability of semantic dementia pati ents to encode, albeit temporarily, recent autobiographical memories v ia a spared hippocampal complex supports the production of highly auto biographically constrained semantic-like facts and, to a lesser extent , frequently encountered names. There is, however, no direct effect of autobiographical experience on previously established semantic memory , i.e. knowledge of golf, bowls, and people, presumably stored within the temporal neocortex. These results are discussed with respect to cu rrent anatomically based computational models of long-term memory.