Evidence for a shrinking span of personal and present existence in dementia of the Alzheimer's type

Severely impaired episodic memory deprives patients with Alzheimer's disease (AD) of a sense of personal continuity in their daily lives, yet there are no tests that accurately measure this impairment. Recently, Zakzanis, Leach, and Moscovitch (1999) examined the integrity of memory function in terms of temporal continuity in a way that would engage the patient in everyday behavior, such as informal conversation, but still allow memory function to be quantified. The task allowed the measurement of the duration of continuous, conscious experience of the present and was therefore termed "span of temporal continuity (STC)." Given that we were able to document static and growing STCs, we wanted to know whether our measure could track progressive memory loss. Accordingly, we followed a patient we believed was in the very early stages of AD to measure the change of his STC longitudinally. Along with his STC, we present our neuropsychological and brain imaging findings over the course of the investigation.