Blessing, A; Zoellig, J; Dammann, G; Martin, M Blessing, A; Zoellig, J; Dammann, G; Martin, M (2010). Implicit learning of affective responses in dementia patients: a face-emotion-association paradigm. Neuropsychology, development, and cognition. Section B, Aging, neuropsychology and cognition, 17(6)

We examined the association of faces with biographical information that varied in emotional content in patients with Alzheimer's disease and a healthy control group. During two experimental sessions, participants rated neutral male faces on dimensions of hedonic valence and emotional arousal, later paired with fictitious biographical information. Both groups changed their ratings of the faces according to the biographical content. Free recall and recognition were tested in the second session. Patients neither recalled the biographical information nor recognized the faces, whereas the controls did. In addition, psychophysiological measures were taken in response to the face stimuli. Patients showed significant heart rate modulation as a function of their emotion ratings, whereas the controls did not. No correlation of rating changes with skin conductance was found in any group. Results suggest that psychophysiological reactions such as heart rate changes may indicate preserved affective associative learning in dementia patients despite impaired explicit memory.

We present results of a study investigating evaluative learning in dementia patients with a classic evaluative conditioning paradigm. Picture pairs of three unfamiliar faces with liked, disliked, or neutral faces, that were rated prior to the presentation, were presented 10 times each to a group of dementia patients (N = 15) and healthy controls (N = 14) in random order. Valence ratings of all faces were assessed before and after presentation. In contrast to controls, dementia patients changed their valence ratings of unfamiliar faces according to their pairing with either a liked or disliked face, although they were not able to explicitly assign the picture pairs after the presentation. Our finding suggests preserved evaluative conditioning in dementia patients. However, the result has to be considered preliminary, as it is unclear which factors prevented the predicted rating changes in the expected direction in the control group.

Main aim of the present study was to investigate if dementia patients can make accurate social and affective judgments of face stimuli. We used verbal material as a control condition to see if dementia patients are capable of using the ratings scales the same way as controls. We compared trustworthiness, valence and arousal ratings of dementia patients with a healthy control group.Participants rated pictures of young and old, female and male neutral faces and two fictitious biographies. The results indicate that dementia patients make accurate judgments of unfamiliar faces with respect to trustworthiness and valence. Results concerning arousal ratings suggest that the corresponding scale might be difficult to use for dementia patients and possibly for older participants as well.

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