Abstract

Background: Alzheimer's disease dementia (ADD) and Parkinson's disease (PD) have a significant impairment in social emotion recognition. Most of these studies assess emotional perception as the ability to identify others' facial emotions (Ekman faces). Nevertheless, emotional recognition with information that integrates whole-body and postural control responses has not been investigated in ADD or PD. Method: 66 participants were recruited (ADD, PD, healthy controls (HC)). Subjects were diagnosed following NINCDS-ADRDA criteria for ADD, and the United Kingdom Parkinson's Disease Society Brain Bank criteria for PD. Inclusion criteria considered older than 60 years and non-other neuropsychiatric comorbidity. All participants were assessed in global cognition (ACE-III), executive function (IFS, FAS), memory (FCRST), and social cognition (Minisea (Faux Pas (FP), Ekman faces (EF)). Three videos were elaborated with persons practicing risk sports (neutral, pleasant, unpleasant); and another unpleasant condition that did not show a human body (car accidents). Videos were previously validated by their emotional properties (120 subjects) following the Self-assessment Manikin. Participants stood up at a force platform while videos (60 seconds) were presented at a TV screen (40 inches) at face height and 1 meter to the front. Postural control data to compute center of pressure (COP) were collected at a sample rate of 125Hz. At the end of each video, participants had to rate (1-9) valence, intensity, and control. COP parameters included velocity, area, and frequency decomposition. Statistical analysis was performed on the first principal component (PC1) on those parameters. Emotional recognition was analyzed by ANOVA (3*3) (group*self-perception), and postural data by Repeated-Measures ANOVA (3*4) (group*emotional condition). Result: Participants with ADD(n=25) show significant impairment in all cognitive domains assessed even when FP was adjusted for control questions, compared to PD(n=14) and HC(n=27). ADD showed significant differences in the recognition of whole-body negative emotions (6,04+2,752), compared to PD (3,71+2,585) and HC (4,19+2,286). When postural control responses were analyzed, the pleasant condition showed significantly bigger displacements (PC1) than the other emotional conditions. Conclusion: ADD participants have problems recognizing negative social emotions that involve whole-body. Emotional stimuli produce changes similar in postural control among groups, which depend on emotional conditions.These results suggest studying the emotion beyond facial emotion.