Temporal order memory differences in Alzheimer's disease and vascular dementia

Determining the order of events is essential for accurate memory recollection: an ability previously linked to both frontal and medial temporal functioning. Frontal-subcortical and medial temporal dysfunction typify vascular dementia (VaD) and Alzheimer's disease (AD), respectively. Therefore, we assessed patients' ordering abilities using a novel sequencing task that progressively increased memory load. VaD patients made more errors and selected more previously encountered stimuli than did AD. Curve analysis revealed a general decline in ordering for VaD whereas error production in AD is more dependent on memory load. These findings generally support the role of frontal-subcortical functioning in temporal order memory.