Overgenerality of autobiographical memory in Alzheimer's disease

Overgenerality of autobiographical memory (ABM) is well documented in a range of clinical conditions, particularly in depressed and parasuicidal patients (e.g., Williams, 1996; Williams & Broadbent, 1986). This study extended the investigation to Alzheimer's disease (AD), and attempted to identify whether ABM overgenerality in the AD group is specifically expressed through an excess of categoric memories.

AD sufferers and control participants were compared on their ABM specificity in a cued-recall task.

Ten AD patients and 10 controls, matched for age, gender and educational level, were administered an ABM specificity measure following their mental status assessment. A battery of neuropsychological tests provided an independent estimate of cognitive deficit severity in the following areas: long-term memory, IQ, working memory, processing speed, and verbal fluency. A control for depression was also employed.

Compared to control participants, AD participants produced significantly fewer specific autobiographical memories. Additionally, the number of produced categoric overgeneral memories was significantly greater in the AD group in comparison with the controls.

This study demonstrates the existence of ABM overgenerality in AD, manifested through an excess of categoric memories. Consistent with the mnemonic interlock theory (Williams, 1996), AD sufferers seem to lack cognitive resources to conduct a directed search for a specific memory, and stop at the categoric descriptions stage. This may contribute to lack of specificity in ABM retrieval.