Semantic Memory and Amnesia: A Case Study

The performance of a severe amnesic patient (AC) was explored across two tasks designed to assess his public and personal semantic knowledge before and after the onset of his amnesia. On the Autobiographical Memory Interview (Kopelman, Wilson, & Baddeley, 1990), AC's ability to recollect specific personal episodes was severely impaired for the three time periods explored (childhood, early adulthood, and contemporary life) but his general (semantic) personal knowledge was relatively preserved even for information that was acquired after the brain injury. The patient was also submitted to a famous people identification task. AC showed a relatively preserved ability to retrieve semantic information concerning famous people who came to fame before his accident. More importantly, AC acquired substantial knowledge about personalities who had become famous after the onset of his amnesia. In addition, the amount of knowledge that he acquired about politicians (a domain he knew particularly well before his accident) did not differ from that of control subjects. These data suggest that AC showed an impairment of episodic memory whereas semantic memory was relatively spared. They also confirm that new semantic learning in amnesics is particularly efficient if the to-be-acquired information is consistent with existing concepts.