Spatial memory retrieval under cueing in behavioral frontotemporal dementia and Alzheimer's disease

Recent studies indicate that episodic memory is impaired in behavioral variant frontotemporal dementia (bvFTD), with deficits as severe as those seen in Alzheimer's disease (AD). Also, both bvFTD and AD patients exhibit executive dysfunction, but the extent to which such dysfunction contributes to memory impairments remains unclear.

The aim of this study was to investigate interactions between executive functions and episodic memory in AD and bvFTD by manipulating executive control in a spatial source memory task.

Twenty bvFTD patients, 18 AD patients, and 20 healthy controls completed a source memory test in which they should remember whether objects were previously seen on the left or right side of a computer screen. Critically, arrow cues (66.7% valid, 33.3% invalid) indicated the likely prior location of each object during retrieval.

bvFTD and AD patients showed overall similar memory performances but were impaired compared to controls. While cueing affected memory performances of controls and bvFTD patients, AD patients showed undistinguishable performances after valid and invalid cueing.

These findings support the notion that episodic memory deficits in bvFTD can be as severe as in AD and demonstrate that, unlike bvFTD patients, patients with AD show difficulties in using information conveyed by cues during memory judgments, probably because of underlying attentional deficits.