Affective states are expressed in an individual’s physical appearance, ranging from facial expressions and body postures, to indicators of physiological arousal (e.g., a blush). Confirming the... Show moreAffective states are expressed in an individual’s physical appearance, ranging from facial expressions and body postures, to indicators of physiological arousal (e.g., a blush). Confirming the claimed communicative function of these markers, humans are capable of distinguishing between a variety of discrete emotion displays. In an attempt to explain the underlying mechanism, characteristic bodily changes within the observer, including physiological arousal and mimicry, have been suggested to facilitate the interpretation of an expression. The current study aims to create a holistic picture of emotion perception by (1) using three different sources of emotional information (prototypical facial expressions, bodily expressions, and subtle facial cues) and (2) measuring changes in multiple physiological signals (facial electromyography, skin conductance level, skin temperature, and pupil size). While participants clearly discriminated between perceived emotional expressions, there was no overall 1–1 correspondence with their physiological responses. Some specific but robust effects were observed. Angry facial expressions were consistently responded to with a peak in skin conductance level. Furthermore, sad body expressions were associated with a drop in skin temperature. In addition to being the best recognized expression, viewing happy faces elicited congruent facial muscle responses, which supports the potential role of embodied simulation in emotion recognition. Lastly, tears were not only rated as highly emotional intense but also evoked a peak in skin conductance level in the observer. The absence of distinct physiological responses to other expressions could be explained by the lacking functionality of affect sharing in a non-interactive experimental context. Consequentially, emotional alignment in body and mind might especially take place in real social situations, which should be considered in future research. Show less
Veeger, T.T.J.; Trigt, B. van; Hu, H.; Bruijn, S.M.; Dieen, J.H. van 2020
BACKGROUND: Literature describing differences in motor control between low back pain (LBP) patients and healthy controls is very inconsistent, which may be an indication for the existence of... Show moreBACKGROUND: Literature describing differences in motor control between low back pain (LBP) patients and healthy controls is very inconsistent, which may be an indication for the existence of subgroups. Pain-related psychological factors might play a role causing these differences.PURPOSE: To examine the relation between fear of movement and variability of kinematics and muscle activation during gait in LBP patients.STUDY DESIGN: Cross-sectional experimental design.PATIENT SAMPLE: Thirty-one Chinese LBP patients.OUTCOME MEASURES: Self-report measures: Visual Analog Score for pain; TAMPA-score; Physiologic measures: electromyography, range of motion.FUNCTIONAL MEASURES: LBP history; the physical load of profession, physical activity.METHODS: Patients were divided in high and low fear of movement groups. Participants walked on a treadmill at four speeds: very slow, slow, preferred and fast. Kinematics of the thorax and the pelvis were recorded, together with the electromyography of five bilateral trunk muscle pairs. Kinematic and electromyography data were analysed in terms of stride-to-stride pattern variability. Factor analysis was applied to assess interdependence of 11 variability measures. To test for differences between groups, a mixed-design multivariate analysis of variance was conducted.RESULTS: Kinematic variability and variability of muscle activation consistently loaded on different factors and thus represented different underlying variables. No significant Group effects on variability of kinematics and muscle activation were found (Hotelling's Trace F=0.237; 0.396, p=.959; .846, respectively). Speed significantly decreased kinematic variability and increased variability in muscle activation (Hotelling's Trace F=8.363; 4.595, p<.0001; <.0001, respectively). No significant interactions between Group and Speed were found (Hotelling's Trace F=0.204; 0.100, p=.762; .963, respectively).CONCLUSIONS: The results of this study do not support the hypothesis that variability in trunk kinematics and trunk muscle activation during gait in LBP patients are associated with fear of movement. (C) 2020 The Author(s). Published by Elsevier Inc. Show less
In the chronic stage of Complex Regional Pain Syndrome (CRPS), motor disturbances are common and cause significant disability. The motor dysfunction of CRPS is a poorly understood phenomenon that... Show moreIn the chronic stage of Complex Regional Pain Syndrome (CRPS), motor disturbances are common and cause significant disability. The motor dysfunction of CRPS is a poorly understood phenomenon that is characterized predominantly by a decrease or loss of voluntary muscle control. This thesis aims to obtain a better understanding of the pathophysiology underpinning the motor dysfunction of CRPS by examining the potential roles of decreased inhibition of the motor system, changes in sensory processing and problems in sensory-motor integration. In specific, characteristics of muscle activity recordings are scrutinized in order to determine whether the loss of voluntary motor control and abnormal postures in CRPS exhibit characteristics of dystonia that are associated with reduced inhibition of the motor system (i.e., excessive muscle activation and enhanced mirror activity). The potential role of impaired processing of proprioceptive information related to wrist orientation and force production is examined, as well as the involuntary and voluntary (sensory-)motor interactions between the affected and unaffected arm. Furthermore, a systematic review of the literature on the motor consequences of experimental pain in healthy humans is presented in order to gain insight into the potential role of pain-related processes in the motor and sensory and motor disturbances of CRPS. Show less
The studies reported in this thesis aimed to survey the prevalence of inclusion body myositis (IBM), to describe its clinical features and course, to investigate whether the major... Show moreThe studies reported in this thesis aimed to survey the prevalence of inclusion body myositis (IBM), to describe its clinical features and course, to investigate whether the major histocompatibility complex predisposed subjects to IBM and autoimmune disorders (AID), to investigate the possible affliction of the neuromuscular junction (NMJ) and finally, to study whether the progression of IBM could be slowed down. On July 1st, 1999, the prevalence was estimated on at least 4.9.10-6 inhabitants in the Netherlands. The incidence rate increased since the 1980s. Time of onset was generally after the age of forty. Symptons at onset could be linked to weakness of the quadriceps muscles , the finger flexors or pharynbgeal muscles. Weakness showed a variable progression rate. Progression of weakness was faster when onset was over the age of 56. Ankylosis was common, but could be helpful in performing skilful movements. Ventral muscles were more frequently and severely affected than dorsal muscles, and girdle muscles were relatively spared, a specific pattern. Repetitive nerve stimulation studies showed normal compound muscle action potential patterns suggestive of normal NMJ transmission. In IBM patients a high frequency of AID was observed. Compared to controls, patients had a high frequency of HLA-antigens of the HLA-A1-B8-DR3-DR52-DQ2 complex. This high frequency could be related to IBM alone and not to the presence of AID. Lastly, in a randomized placebo controlled trial with methotrexate no important effect on weakness progression could be demonstrated. Show less
