Patterns of errors in short-term forgetting in AD and ageing

This study examined whether the low performance of 40 AD patients in the Br own-Peterson task could be explained by a pattern of errors that differed f rom 55 elderly controls. Our quantitative results showed that AD patients h ad a lower performance level in the three retention intervals than controls but a significant interaction between group and interval was not found, in dicating that the rate of forgetfulness was similar in the two groups. In o ur qualitative analysis, errors were categorised as confusions, perseverati ons, omissions, and order alterations. Contrary to other studies (Dannenbau m, Parkinson, & Inman, 1988; Kopelman, 1985) where an AD forgetfulness tend ency of omissions was observed, our data showed an excess of perseveration (even more than five repetitions), indicating problems in the central execu tive. This could be interpreted in terms of problems in updating the conten ts of working memory.