Retrograde amnesia for autobiographical memories and public events in mild and moderate Alzheimer's disease.

Patients with mild to moderate Alzheimer's disease and normal controls were tested on two retrograde memory tests, one based on public events, and the other querying autobiographical memory. On both tests, patients showed strong decrements as compared to normal controls, pointing to retrograde amnesia. Evidence for a gradient in retrograde amnesia was conflicted, with analyses of variance revealing no gradient beyond the most recent period, and more sensitive analyses pointing to shallow Ribot gradients on both tests. A literature review shows that this is the case in most published studies. In autobiographical remote memory patients generated many incorrect answers, a tendency correlated with the number of false alarms on an anterograde memory test administered several months earlier. This suggests a stable, possibly executive, factor underlying memory errors.