Session Title: Alzheimer's Disease (AD) including Non-Cognitive Aspects
WHAT MEMORY BINDING DEFICITS CAN TELL US ABOUT ALZHEIMER'S DISEASE?
M. Parra, S. Della Sala, S. Abrahams, R. Logie
Patients with Alzheimer' Disease (AD) have particular difficulties in remembering associations between stimuli (e.g. names of people). The mechanism underlying this memory deterioration is poorly understood. We hypothesize that an impairment in binding, a function underpinning the representation of integrated objects in memory, may be targeted by AD in its early stages. In two experiments we investigated whether patients with AD would have difficulties to bind information in memory and whether these problems develop earlier than other episodic memory deficits. The first experiment investigated the binding of nonverbal information using a change detection task. Fifteen AD patients and fifteen healthy older adults were asked to study visual arrays displaying random polygons, colours, or polygons in colours. After 900 msec they judged whether probe arrays consisted of the same or different items. The second experiment investigated whether memory binding problems develop earlier than non-associative memory deficits. Fourteen pre-symptomatic carriers of a gene mutation (E280A of the gene of the Presenilin-1) leading to early onset AD, fourteen symptomatic carriers with minimal AD, and seventeen non-carrier relatives performed the task described in Experiment 1. The results suggest that: