Time estimation in Alzheimer's disease and the role of the central executive.

The aim of this study was to evaluate the role of short-term memory and attention in time estimation. For this purpose we studied prospective time verbal estimation in 21 patients with Alzheimer's disease (AD), and compared their performance with that of 21 matched normal controls in two different conditions: during a digit span task and during an attentional task. Results showed that the performance of AD patients was significantly worse than that of the controls; the interaction between group and condition was significant. We suggest a role of attentional-executive functions in prospective time estimation.