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Semantic dementia patients seem to have better knowledge of information linked to the self. More specifically, despite having severe semantic impairment, these patients show that they have more general information about the people they know personally by direct experience than they do about other individuals they know indirectly. However, the role of direct personal experience remains debated because of confounding factors such as frequency, recency of exposure, and affective relevance. We performed an exploratory study comparing the performance of 5 semantic dementia patients with that of 10 matched healthy controls on the recognition (familiarity judgment) and identification (biographic information recall) of personally familiar names versus famous names. As expected, intergroup comparisons indicated a semantic breakdown in semantic dementia patients as compared with healthy controls. Moreover, unlike healthy controls, the semantic dementia patients recognized and identified personally familiar names better than they did famous names. This pattern of results suggests that direct personal experience indeed plays a specific role in the relative preservation of person-specific semantic meaning in semantic dementia. We discuss the role of direct personal experience on the preservation of semantic knowledge and the potential neurophysiological mechanisms underlying these processes.

Autobiographical memory and social cognition share common properties and both are affected in autism spectrum disorders (ASD). So far, most of the scant research in ASD has concerned adults, systematically reporting impairment of the episodic component. The only study to be conducted with children concluded that they have poorer personal semantic knowledge than typical developing children. The present study explores the development of both components of autobiographical memory in an 8-year-old boy diagnosed with Asperger’s syndrome, based on three examinations in 2007, 2008 and 2010. On each occasion, he underwent a general neuropsychological assessment including theory of mind tasks, and a specially-designed autobiographical memory task allowing us to test both the semantic and the episodic components for three lifetime periods (current year, previous year and earlier years). We observed difficulties in strategic retrieval and theory of mind, with a significant improvement between the second and third examinations. Regarding autobiographical memory, different patterns of performance were noted in all three examinations: 1) relative preservation of current-year personal knowledge, but impairment for the previous and earlier years, and 2) impairment of episodic memory for the current and previous year, but performances similar to those of controls for the earlier years. The first pattern can be explained by abnormal forgetting and by the semanticization mechanism, which needs verbal communication and social interaction to be efficient. The second pattern suggests that the development of episodic memory only reached the stage of event memory. This term refers to memory for personal events lacking in details or spatiotemporal specificity, and is usually observed in children younger than 5. We conclude that the abnormal functioning of social cognition in ASD, encompassing social and personal points of view, has an impact on both components of autobiographical memory.