Machine Analysis of Facial Expressions

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The interest of gait markers in the identification of subgroups among fibromyalgia patients

<p>Abstract</p> <p>Background</p> <p>Fibromyalgia (FM) is a heterogeneous syndrome and its classification into subgroups calls for broad-based discussion. FM subgrouping, which aims to adapt treatment according to different subgroups, relies in part, on psychological and cognitive dysfunctions. Since motor control of gait is closely related to cognitive function, we hypothesized that gait markers could be of interest in the identification of FM patients' subgroups. This controlled study aimed at characterizing gait disorders in FM, and subgrouping FM patients according to gait markers such as stride frequency (SF), stride regularity (SR), and cranio-caudal power (CCP) which measures kinesia.</p> <p>Methods</p> <p>A multicentre, observational open trial enrolled patients with primary FM (44.1 ± 8.1 y), and matched controls (44.1 ± 7.3 y). Outcome measurements and gait analyses were available for 52 pairs. A 3-step statistical analysis was carried out. A preliminary single blind analysis using k-means cluster was performed as an initial validation of gait markers. Then in order to quantify FM patients according to psychometric and gait variables an open descriptive analysis comparing patients and controls were made, and correlations between gait variables and main outcomes were calculated. Finally using cluster analysis, we described subgroups for each gait variable and looked for significant differences in self-reported assessments.</p> <p>Results</p> <p>SF was the most discriminating gait variable (73% of patients and controls). SF, SR, and CCP were different between patients and controls. There was a non-significant association between SF, FIQ and physical components from Short-Form 36 (p = 0.06). SR was correlated to FIQ (p = 0.01) and catastrophizing (p = 0.05) while CCP was correlated to pain (p = 0.01). The SF cluster identified 3 subgroups with a particular one characterized by normal SF, low pain, high activity and hyperkinesia. The SR cluster identified 2 distinct subgroups: the one with a reduced SR was distinguished by high FIQ, poor coping and altered affective status.</p> <p>Conclusion</p> <p>Gait analysis may provide additional information in the identification of subgroups among fibromyalgia patients. Gait analysis provided relevant information about physical and cognitive status, and pain behavior. Further studies are needed to better understand gait analysis implications in FM.</p

Theory of Robot Communication: II. Befriending a Robot over Time

In building on theories of Computer-Mediated Communication (CMC), Human-Robot Interaction, and Media Psychology (i.e. Theory of Affective Bonding), the current paper proposes an explanation of how over time, people experience the mediated or simulated aspects of the interaction with a social robot. In two simultaneously running loops, a more reflective process is balanced with a more affective process. If human interference is detected behind the machine, Robot-Mediated Communication commences, which basically follows CMC assumptions; if human interference remains undetected, Human-Robot Communication comes into play, holding the robot for an autonomous social actor. The more emotionally aroused a robot user is, the more likely they develop an affective relationship with what actually is a machine. The main contribution of this paper is an integration of Computer-Mediated Communication, Human-Robot Communication, and Media Psychology, outlining a full-blown theory of robot communication connected to friendship formation, accounting for communicative features, modes of processing, as well as psychophysiology.Comment: Hoorn, J. F. (2018). Theory of robot communication: II. Befriending a robot over time. arXiv:cs, 2502572(v1), 1-2

Placebo effects in health and disease : how expectations shape treatment outcomes

The context in which a medical treatment is administrated influences treatment outcomes. As of today, the health care system has little knowledge about the non-specific components that contribute to the positive effect of a given therapy, often referred to as the placebo component, and how this may be harnessed in order to maximize treatment effects. The overreaching aim of this doctoral thesis is to investigate the impact of non-specific treatment components on clinical outcomes, in particular the role of expectations. More specifically, this thesis focuses on two clinically relevant, yet poorly investigated, topics: 1) Are placebo effects dependent on higher order cognitions? This was investigated among patients with intellectual disability (ID) and in an experimental setting in healthy individuals. 2) Are placebo effects affected by the duration of a chronic disease? In order to study this, outcomes from a randomized controlled trial (RCT) among fibromyalgia (FM) patients were analyzed. Study I investigated the influence of non-conscious expectations on placebo analgesia, using an implicit priming task called Scrambled Sentence Test (SST). Healthy participants were randomized to receive positive or neutral expectations via the SST, followed by a placebo manipulation with a sham analgesic device. Results demonstrated no effect of implicit priming on placebo analgesia, yet the study indicates that placebo analgesia is largely explained by prior experience of pain relief, and that the social interaction with a trustworthy clinician may have competed with the possible effect of implicit priming. Study II examined the relationship between placebo analgesia and the time (months, years) a person has been exposed to chronic disease, by assessing placebo responses in a pharmacological trial in patients with FM. Results revealed that FM duration was associated with baseline pain levels as well as placebo analgesia. These results point to the importance of early FM interventions, as the chance to harness endogenous pain regulation and to avoid chronification may be higher early in the disease course. Study III investigated how treatment expectations may shape outcomes in pharmacological clinical trials among patients with ID. The placebo component in ID clinical trials was examined by performing a meta-analysis comparing drug responses in open-label trials (with 100% certainty of getting the real drug) with drug responses in placebo-controlled trials (with 50% chance of getting the real drug). The results demonstrated placebo effects among patients with ID, as the effect of the real drug in open-label context was associated with better treatment outcomes than the same drug in a placebo-controlled context. Our study validates the notion that patients with ID are influenced by contextual factors in clinical trials in spite of severe cognitive deficits

The Role of Reward Sensitivity in the Perpetration of Reactive and Proactive Aggression

Research has implicated reward sensitivity as one potential shared mechanism underlying reactive and proactive aggression. The current study examined the effect of reward sensitivity, assessed multi-modally through a behavioral task and self-report, on the perpetration of reactive and proactive aggression assessed via a laboratory paradigm. Participants were 184 undergraduate men and women. Hierarchical linear regression revealed positive main effect of reward sensitivity on aggression that did not differ according to condition. This finding offers initial evidence for reward sensitivity as a common etiological correlate of reactive and proactive aggression. And supports future research on shared risk factors that could be targeted to reduce both reactive and proactive aggression