Action-based memory in Alzheimer's disease: a longitudinal look at tea making.

In this paper we report the results of a longitudinal study which examined memory for a single routine activity of daily living in people with dementia of the Alzheimer type. We assessed memory in a natural setting, visiting volunteers in their homes. We video-taped performance on the selected task and analysed the record for the presence or absence of each of its component actions over a period of 6 years. In this way, we obtained longitudinal data for a small group of people moving from the mild-moderate stages of dementia through to severe dysfunction. In the first section of this paper we examine the nature of the errors which are made in recall of a routine activity by volunteers with dementia of the Alzheimer type and what happens to that routine as the dementia erodes memory. In the second section we examine the consequence of moving the routine from a familiar setting to a novel setting. We observed large differences in the rate of decline of our volunteers, with substantial preservation of performed recall of the everyday task, even in the more severe phases of the disease. The pattern of decline suggests a benign degradation of the memory trace, with omissions comprising the most common category of errors, and this result is contrasted with the more dramatic action disorganization syndrome associated with frontal injury. The results have implications both for theoretical models of action-based memory and intervention programmes aimed at maintaining functional independence for people with dementia.