DISCRIMINATION OF FACIAL EXPRESSIONS OF EMOTION IN ALZHEIMER PATIENTS: DISENTANGLING CRITERIA AND SENSITIVITY PARAMETERS OVER DIFFERENT FACETS OF EXPRESSION
Whether Alzheimer patients present a deficit in the perception of emotional expressions conveyed by faces has remained a matter of debate over the last few years. Conflicting evidence has been presented, stemming in part from methodological inadequacies in the approaches taken, in another part from lack of consideration of specific deficit hypothesis. This study aims at contributing to circumvent both shortcomings by resorting to a signal detection approach, tailored moreover to consider distinct locus of impact of such a potential deficit: upon the discrimination between 1) neutral-emotional faces; 2) emotion categories; 3) valence sign; 4) emotion intensities. Comparisons with matched groups of controls revealed similar qualitative patterns but important quantitative differences on both criteria and sensitivity indices. Sensitivity parameters calculated from intensities discrimination were shown partially dissociable from general cognitive decline and of potential diagnostic interest.