Estimation of short temporal intervals in Alzheimer's disease.

This study investigated the estimation of short temporal intervals in Alzheimer's disease (AD). Eight patients with dementia of the Alzheimer type, and eight age-matched controls were evaluated in a time-estimation task. The task consisted in the production of three short empty intervals (5, 10, and 25 s). Results indicated that AD patients show deficits both in the accuracy and precision of time judgments: in the three intervals evaluated, the magnitude of absolute error and the variability in time judgments were significantly greater in AD patients than healthy respondents (p < .01). These findings are discussed taking into account the contribution of attentional processes during the performance of temporal tasks. It is concluded that the estimation of short temporal intervals could be useful as an objective indicator of cognitive decline in AD.