Memory for performed actions in dementia of Alzheimer type: further evidence for a global semantic memory deficit

Findings in patients with dementia of the Alzheimer type (AD patients) concerning the enactment effect, i.e. reaching a better memory performance after encoding actions by performing them in contrast to encoding them by reading, are ambiguous. In order to get more insight into memory deterioration in patients suffering from AD, an experimental study was run. Patients with mild-to-moderate AD (n = 23) and healthy elderly control persons (n = 20) took part. They had to encode actions verbally as well as enactively. Memory performance was tested by using recognition judgments instead of the predominating free recall. The AD patients showed no enactment effect and a rate of false alarm judgments that was more than twice as high as found in healthy elderly controls. This enactive encoding failure may be indicative of memory deficits underlying the conceptual system of action representations.