RESUMO
OBJECTIVES: Facial expressions are a core component of emotions and nonverbal social communication. Therefore, hypomimia as secondary symptom of Parkinson's disease (PD) has adverse effects like social impairment, stigmatization, under-diagnosis and under-treatment of depression, and a generally lower quality of life. Beside unspecific dopaminergic treatment, specific treatment options for hypomimia in PD are rarely investigated. This quasi-randomized controlled trial evaluated the short-term effects of facial electromyogram (EMG) based biofeedback to enhance facial expression and emotion recognition as nonverbal social communication skills in PD patients. Furthermore effects on affect are examined. METHOD: A sample of 34 in-patients with PD were allocated either to facial EMG-biofeedback as experimental group or non-facial exercises as control group. Facial expression during posing of emotions (measured via EMG), facial emotion recognition, and positive and negative affect were assessed before and after treatment. Stronger improvements were expected in the EMG-biofeedback in comparison to the control group. RESULTS: The facial EMG-biofeedback group showed significantly greater improvements in overall facial expression, and especially for happiness and disgust. Also, overall facial emotion recognition abilities improved significantly stronger in the experimental group. Positive affect was significantly increased in both groups with no significant differences between them, while negative affect did not change within both groups. CONCLUSIONS: The study provides promising evidence for facial EMG-biofeedback as a tool to improve facial expression and emotion recognition in PD. Embodiment theories are discussed as working mechanism.
Assuntos
Reconhecimento Facial , Doença de Parkinson , Humanos , Doença de Parkinson/complicações , Doença de Parkinson/psicologia , Qualidade de Vida , Emoções , Face , Expressão Facial , Biorretroalimentação PsicológicaRESUMO
A growing literature suggests that preverbal infants are sensitive to sociomoral scenes and prefer prosocial agents over antisocial agents. It remains unclear, however, whether and how emotional processes are implicated in infants' responses to prosocial/antisocial actions. Although a recent study found that infants and toddlers showed more positive facial expressions after viewing helping (vs. hindering) events, these findings were based on naïve coder ratings of facial activity; furthermore, effect sizes were small. The current studies examined 18- and 24-month-old toddlers' real-time reactivity to helping and hindering interactions using three physiological measures of emotion-related processes. At 18 months, activity in facial musculature involved in smiling/frowning was explored via facial electromyography (EMG). At 24 months, stress (sweat) was explored via electrodermal activity (EDA). At both ages, arousal was explored via pupillometry. Behaviorally, infants showed no preferences for the helper over the hinderer across age groups. EMG analyses revealed that 18-month-olds showed higher corrugator activity (more frowning) during hindering (vs. helping) actions, followed by lower corrugator activity (less frowning) after hindering (vs. helping) actions finished. These findings suggest that antisocial actions elicited negativity, perhaps followed by brief disengagement. EDA analyses revealed no significant event-related differences. Pupillometry analyses revealed that both 18- and 24-month-olds' pupils were smaller after viewing hindering (vs. helping), replicating recent evidence with 5-month-olds and suggesting that toddlers also show less arousal following hindering than following helping. Together, these results provide new evidence with respect to whether and how arousal/affective processes are involved when infants process sociomoral scenarios.
Assuntos
Emoções , Lactente , Humanos , Pré-Escolar , Emoções/fisiologia , Face , Músculos Faciais , Nível de Alerta , Expressão FacialRESUMO
Understanding the association between subjective emotional experiences and physiological signals is of practical and theoretical significance. Previous psychophysiological studies have shown a linear relationship between dynamic emotional valence experiences and facial electromyography (EMG) activities. However, whether and how subjective emotional valence dynamics relate to facial EMG changes nonlinearly remains unknown. To investigate this issue, we re-analyzed the data of two previous studies that measured dynamic valence ratings and facial EMG of the corrugator supercilii and zygomatic major muscles from 50 participants who viewed emotional film clips. We employed multilinear regression analyses and two nonlinear machine learning (ML) models: random forest and long short-term memory. In cross-validation, these ML models outperformed linear regression in terms of the mean squared error and correlation coefficient. Interpretation of the random forest model using the SHapley Additive exPlanation tool revealed nonlinear and interactive associations between several EMG features and subjective valence dynamics. These findings suggest that nonlinear ML models can better fit the relationship between subjective emotional valence dynamics and facial EMG than conventional linear models and highlight a nonlinear and complex relationship. The findings encourage emotion sensing using facial EMG and offer insight into the subjective-physiological association.
Assuntos
Emoções , Expressão Facial , Humanos , Eletromiografia , Emoções/fisiologia , Face , Músculos Faciais/fisiologia , Aprendizado de MáquinaRESUMO
Surface facial electromyography (EMG) is commonly used to detect emotions from subtle facial expressions. Although there are established procedures for collecting EMG data and some aspects of their processing, there is little agreement among researchers about the optimal way to process the EMG signal, so that the study-unrelated variability (noise) is removed, and the emotion-related variability is best detected. The aim of the current paper was to establish an optimal processing pipeline for EMG data for identifying emotional expressions in facial muscles. We identified the most common processing steps from existing literature and created 72 processing pipelines that represented all the different processing choices. We applied these pipelines to a previously published dataset from a facial mimicry experiment, where 100 adult participants observed happy and sad facial expressions, whilst the activity of their facial muscles, zygomaticus major and corrugator supercilii, was recorded with EMG. We used a resampling approach and subsets of the original data to investigate the effect and robustness of different processing choices on the performance of a logistic regression model that predicted the mimicked emotion (happy/sad) from the EMG signal. In addition, we used a random forest model to identify the most important processing steps for the sensitivity of the logistic regression model. Three processing steps were found to be most impactful: baseline correction, standardisation within muscles, and standardisation within subjects. The chosen feature of interest and the signal averaging had little influence on the sensitivity to the effect. We recommend an optimal processing pipeline, share our code and data, and provide a step-by-step walkthrough for researchers.
RESUMO
Fear and anxiety are the most frequently studied emotional states in chemosignal research. Despite differences between these two emotional states, findings from research using fear and anxiety body odors (BOs) are often treated as part of a similar phenomenon. In this article, we examine possible similarities and differences between participants exposed to fear and anxiety BOs on 2 dependent variables commonly used in chemosignals' research: (1) the activation of facial muscles in displays of fear expressions (i.e. the medial frontalis and the corrugator supercilii); and (2) the time required to discriminate between negative emotional expressions (fear, anger, and disgust) and neutral ones. Our results show that fear (vs. rest) and anxiety (vs. exercise) BOs activate the medial frontalis, suggesting that both have a similar impact on receivers' facial muscles. However, we could not replicate previous findings regarding the influence of fear BOs in discriminating negative emotional faces from neutral ones. Two additional replication attempts failed to replicate the earlier results, indicating that the results reported in the literature with this specific paradigm should be interpreted cautiously. Suggestions for future research examining possible differences between fear and anxiety BOs are advanced.
Assuntos
Expressão Facial , Músculos Faciais , Humanos , Músculos Faciais/fisiologia , Medo , Emoções/fisiologia , AnsiedadeRESUMO
There is ample evidence that electromyography (EMG) signals from the corrugator supercilii and zygomatic major muscles can provide valuable information for the assessment of subjective emotional experiences. Although previous research suggested that facial EMG data could be affected by crosstalk from adjacent facial muscles, it remains unproven whether such crosstalk occurs and, if so, how it can be reduced. To investigate this, we instructed participants (n = 29) to perform the facial actions of frowning, smiling, chewing, and speaking, in isolation and combination. During these actions, we measured facial EMG signals from the corrugator supercilii, zygomatic major, masseter, and suprahyoid muscles. We performed an independent component analysis (ICA) of the EMG data and removed crosstalk components. Speaking and chewing induced EMG activity in the masseter and suprahyoid muscles, as well as the zygomatic major muscle. The ICA-reconstructed EMG signals reduced the effects of speaking and chewing on zygomatic major activity, compared with the original signals. These data suggest that: (1) mouth actions could induce crosstalk in zygomatic major EMG signals, and (2) ICA can reduce the effects of such crosstalk.
Assuntos
Face , Expressão Facial , Humanos , Eletromiografia , Emoções/fisiologia , Músculos Faciais/fisiologiaRESUMO
Children's narcissism may be rooted in sensitivity to social status (i.e., prominence, respect, and influence in a social group), and this sensitivity might be shared with parents. Testing this idea, a randomized experiment examined how children with high narcissism levels and their parents respond to gains and losses of social status. On a simulated social media platform, children (N = 123, ages 8-13) competed with fictitious peers for status and were randomly assigned to gain or lose status. Unbeknownst to children, parents viewed the course of the task. Children's and parents' affective reactions during the task were measured with facial electromyography, which detects spontaneous facial muscle activity linked to positive affect (i.e., zygomaticus major activity, involved in smiling) and negative affect (i.e., corrugator supercilii activity, involved in frowning). Children with higher narcissism levels showed steeper increases in negative affect during status loss and steeper increases in both positive and negative affect during status gain. Their parents mirrored the steeper increase in positive affect during their child's status gain, but they did not mirror the increase in negative affect. These results suggest that children with high narcissism levels and their parents show intensified affective-motivational responses to children's status-relevant experiences. These responses may be transmitted from one generation to the other (e.g., genetically or through parent-child socialization).
Assuntos
Narcisismo , Distância Psicológica , Acidentes por Quedas , Adolescente , Criança , Humanos , Pais , SocializaçãoRESUMO
The lateral spread response (LSR) on preoperative facial electromyogram (EMG) is a useful tool in evaluating patients with hemifacial spasm (HFS). There may be some instances where the LSR does not appear on the preoperative EMG, thus disrupting the diagnosis and treatment of HFS. In this study, we evaluated the patients who did not exhibit LSR on preoperative EMG but underwent microvascular decompression (MVD) for hemifacial spasm. We searched for patients who underwent MVD for HFS but had an absence of LSR on preoperative EMG between January 2016 and June 2018. Surgical outcomes were evaluated at 1, 3, and 6 months after surgery. Follow-up facial EMG was performed 3 months after surgery. Results were divided into two categories: (1) spasm relief within 24 h of surgery and (2) spasm was observed immediately post-operation. The following parameters were analyzed when comparing between the two groups: age, sex, affected side, duration of symptoms, and offending vessel(s). A total of 306 patients underwent MVD for HFS during the study period. Among them, 13 (4.2%) patients had no LSR on preoperative EMG. Eight patients (61.5%) were female and five patients were male. The 13 patients had a mean age of 51 years. All patients exhibited probable offending vessels in the root exit zone (REZ) of the facial nerve on preoperative magnetic resonance (MR) imaging that was confirmed during surgery. Seven patients were free of HFS immediately after surgery, though six patients were not. Only one (7.7%) patient had persisted symptom 6 months after surgery. No patients experienced recurrence of spasm, nor exhibited abnormal waves on follow-up facial EMG. LSR on facial EMG is a valuable tool for evaluating hemifacial spasm. However, although LSR did not appear on preoperative EMG, if the patient presents with typical symptoms and the offending vessels are identified on MRI, we expect good results after MVD for HFS.
Assuntos
Espasmo Hemifacial , Cirurgia de Descompressão Microvascular , Eletromiografia , Nervo Facial/cirurgia , Feminino , Espasmo Hemifacial/diagnóstico , Espasmo Hemifacial/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Decoding someone's facial expressions provides insights into his or her emotional experience. Recently, Automatic Facial Coding (AFC) software has been developed to provide measurements of emotional facial expressions. Previous studies provided first evidence for the sensitivity of such systems to detect facial responses in study participants. In the present experiment, we set out to generalise these results to affective responses as they can occur in variable social interactions. Thus, we presented facial expressions (happy, neutral, angry) and instructed participants (N = 64) to either actively mimic, to look at them passively (n = 21), or to inhibit their own facial reaction (n = 22). A video stream for AFC and an electromyogram (EMG) of the zygomaticus and corrugator muscles were registered continuously. In the mimicking condition, both AFC and EMG differentiated well between facial expressions in response to the different emotional pictures. In the passive viewing and in the inhibition condition AFC did not detect changes in facial expressions whereas EMG was still highly sensitive. Although only EMG is sensitive when participants intend to conceal their facial reactions, these data extend previous findings that Automatic Facial Coding is a promising tool for the detection of intense facial reaction.
Assuntos
Emoções , Expressão Facial , Ira , Eletromiografia , Músculos Faciais , Feminino , Humanos , MasculinoRESUMO
How do affective feelings arise? Most theories consider that affective feelings result from the appraisals of an event, these appraisals being the consequences of automatic evaluations processes that can occur pre-consciously. However, studies testing this hypothesis have provided divergent results. We hypothesised that the discrepancy could be due to the visibility of the affective stimuli. We conducted two studies in which we manipulated this factor. Moreover, to exclude a possible explanation of these effects in terms of semantic priming or of experimental demand, we measured participants' facial expressions with EMG in addition to self-report measures (BMIS). The two studies showed that repeated brief exposure to visible positive stimuli (words, Experiment 1 - pictures, Experiment 2) led to more positive feelings than exposure to negative stimuli. In contrast, when the stimuli were masked, the reversed pattern of results was observed. Results on facial EMG indicate similar effects. Consistent with the automatic evaluation hypothesis, the results suggest that assimilative effects of affective stimuli on affective feelings can be observed after a repeated brief presentation of primes, provided that the stimuli are visible. The contrast effects observed when stimuli were masked appear reliable but remain in need for further theoretical explanation.
Assuntos
Afeto , Expressão Facial , Adulto , Estado de Consciência , Eletromiografia , Emoções , Face , Feminino , Humanos , Masculino , Semântica , Adulto JovemRESUMO
Since the advent of the concept of empathy in the scientific literature, it has been hypothesized, although not necessarily empirically verified, that empathic processes are essential to aesthetic experiences of visual art. We tested how the ability to "feel into" ("Einfühlung") emotional content-a central aspect of art empathy theories-affects the bodily responses to and the subjective judgments of representational and abstract paintings. The ability to feel into was measured by a standardized pre-survey on "emotional contagion"-the ability to pick up and mirror, or in short to "feel into", emotions, which often overlaps with higher general or interpersonal empathetic abilities. Participants evaluated the artworks on several aesthetic dimensions (liking, valence, moving, and interest), while their bodily reactions indicative of empathetic engagement (facial electromyography-EMG, and skin conductance responses-SCR) were recorded. High compared to low emotion contagion participants showed both more congruent and more intense bodily reactions (EMG and SCR) and aesthetic evaluations (higher being moved, valence, and interest) and also liked the art more. This was largely the case for both representational and abstract art, although stronger with the representational category. Our findings provide tentative evidence for recent arguments by art theorists for a close "empathic" mirroring of emotional content. We discuss this interpretation, as well as a potential tie between emotion contagion and a general increase in emotion intensity, both of which may impact, in tandem, the experience and evaluation of art.
Assuntos
Arte , Eletromiografia/métodos , Emoções/fisiologia , Empatia/fisiologia , Estética , Músculos Faciais/fisiologia , Resposta Galvânica da Pele/fisiologia , Julgamento/fisiologia , Adulto , Feminino , Humanos , MasculinoRESUMO
When interacting with other people, both children's biological predispositions and past experiences play a role in how they will process and respond to social-emotional cues. Children may partly differ in their reactions to such cues because they differ in the threshold for perceiving such cues in general. Theoretically, perceptual sensitivity (i.e., the amount of detection of slight, low-intensity stimuli from the external environment independent of visual and auditory ability) might, therefore, provide us with specific information on individual differences in susceptibility to the environment. However, the temperament trait of perceptual sensitivity is highly understudied. In an experiment, we tested whether school-aged children's (N=521, 52.5% boys, Mage=9.72years, SD=1.51) motor (facial electromyography) and affective (self-report) reactivities to dynamic facial expressions and vocalizations is predicted by their (parent-reported) perceptual sensitivity. Our results indicate that children's perceptual sensitivity predicts their motor reactivity to both happy and angry expressions and vocalizations. In addition, perceptual sensitivity interacted with positive (but not negative) parenting behavior in predicting children's motor reactivity to these emotions. Our findings suggest that perceptual sensitivity might indeed provide us with information on individual differences in reactivity to social-emotional cues, both alone and in interaction with parenting behavior. Because perceptual sensitivity focuses specifically on whether children perceive cues from their environment, and not on whether these cues cause arousal and/or whether children are able to regulate this arousal, it should be considered that perceptual sensitivity lies at the root of such individual differences.
Assuntos
Sinais (Psicologia) , Emoções/fisiologia , Expressão Facial , Poder Familiar/psicologia , Percepção Visual/fisiologia , Adolescente , Adulto , Criança , Eletromiografia , Feminino , Humanos , Individualidade , Masculino , Estimulação Luminosa , Adulto JovemRESUMO
OBJECTIVES: Evidence suggests that obsessive-compulsive disorder (OCD) is characterized by heightened self-reported disgust, however, it is unclear if this extends to physiology. The relationship between obsessive beliefs and disgust also remains poorly understood. Therefore, we examined whether the heightened trait and self-reported disgust observed in individuals with OCD is reflected in heightened physiological disgust responses. We also examined whether obsessive beliefs are associated with disgust responding. DESIGN: A 3 (group) × 6 (stimulus) repeated measures design was used to examine disgust responses in individuals with OCD to six categories of image stimuli: body waste, contamination, injury, sociomoral, neutral, negative non-disgust. METHODS: Individuals with OCD (n = 25) were compared to individuals with non-OCD anxiety disorders (n = 21) and healthy participants (n = 25) with respect to trait, self-reported, facial electromyographic and electrodermal disgust responses. RESULTS: Individuals with OCD showed greater disgust propensity and self-reported disgust to images of body waste compared to healthy and anxious participants, however, there were no group differences in physiological responses. After controlling for trait disgust, obsessive beliefs positively correlated with increased self-reported disgust to neutral images and increased levator labii activity to negative non-disgusting images. CONCLUSIONS: Although individuals with OCD showed elevated disgust propensity and self-reported ratings of body waste stimuli, there was little evidence that OCD is characterized by an abnormal physiological disgust response. The intensity of obsessive beliefs was associated with a tendency to respond with disgust in contexts that are non-disgusting, indicating that obsessive beliefs may be implicated in pathological disgust. PRACTITIONER POINTS: Individuals with OCD display greater levels of disgust propensity and self-reported disgust to images of body waste compared to healthy control participants and individuals with non-OCD anxiety disorders. The abnormalities in self-reported disgust observed in those with OCD do not extend to abnormalities in electrodermal activity or facial electromyographic responses. Maladaptive obsessive beliefs commonly associated with OCD predict heightened disgust in contexts where objective sources of disgust are absent, even after controlling for trait disgust. Maladaptive obsessive beliefs may therefore be implicated in pathological disgust. This study used a heterogeneous OCD sample and future research is needed to determine whether the observed effects are greater for those with primarily washing and contamination symptoms. Although group differences emerged in self-reported disgust, further replications using measures of state anxiety are needed to rule out the possibility that heightened self-reported disgust was confounded with co-occurring fear or general negative affect.
Assuntos
Cognição/fisiologia , Emoções/fisiologia , Medo/psicologia , Transtorno Obsessivo-Compulsivo/psicologia , Adulto , Ansiedade/psicologia , Transtornos de Ansiedade/diagnóstico , Transtornos de Ansiedade/psicologia , Eletromiografia , Expressão Facial , Feminino , Resposta Galvânica da Pele , Humanos , Entrevistas como Assunto , Masculino , Análise de Regressão , Autorrelato , Inquéritos e QuestionáriosRESUMO
A patient who needs a surgery for facial rehabilitation must have a complete assessment. The etiology of the facial palsy must be clear. It is necessary to have a MRI of the facial nerve for the statement of the initial pathology or to search a lesion on the nerve. The facial palsy must be definite which is depending of the delay of the palsy and the etiology. An electromyography must be done. The choice of the procedure depends on the delay of the palsy, the site on the nerve, the associated diseases and the opinion of the patient after a good explanation.
Assuntos
Paralisia Facial/reabilitação , Eletromiografia , Nervo Facial/diagnóstico por imagem , Paralisia Facial/etiologia , Paralisia Facial/cirurgia , Humanos , Imageamento por Ressonância Magnética , Cuidados Pré-OperatóriosRESUMO
The present study aimed to investigate whether facial electromyography (EMG) recordings reflect the perception of effort and primary active lower limb muscle activity during incremental workload cycling. The effects of exercise intensity on EMG activity of the corrugator supercilii (CS), masseter and vastus lateralis (VL) muscles, heart rate (HR) and the rating of perceived exertion (RPE) were investigated, and the correlations among these parameters were determined. Eighteen males and 15 females performed continuous incremental workload cycling exercise until exhaustion. CS, masseter and VL muscle activities were continuously recorded using EMG during exercise. HR was also continuously monitored during the test. During the final 30 s of each stage of cycle ergometer exercise, participants were asked to report their feeling of exertion on the adult OMNI-Cycle RPE. HR and EMG activity of the facial muscles and the primary active lower limb muscle were strongly correlated with RPE; they increased with power output. Furthermore, facial muscle activity increased significantly during high-intensity exercise. Masseter muscle activity was strongly and positively correlated with HR, RPE and VL activity. The present investigation supports the view that facial EMG activity reflects the perception of effort. The jaw clenching facial expression can be considered an important factor for improving the reporting of perceived effort during high-intensity exercise in males and females. Key pointsFrowning and jaw clenching muscle activity reflects the perception of effort during incremental workload cycling.EMG activity of the masseter muscle was strongly and positively correlated with RPE, HR and lower limb EMG activity during incremental workload cycling.The jaw clenching facial expression can be considered an important factor for estimating the intensity of effort.
RESUMO
We measured participants' psychophysiological responses and gaze behavior while viewing a stimulus person's direct and averted gaze in three different conditions manipulating the participants' experience of being watched. The results showed that skin conductance responses and heart rate deceleration responses were greater to direct than averted gaze only in the condition in which the participants had the experience of being watched by the other individual. In contrast, gaze direction had no effects on these responses when the participants were manipulated to believe that the other individual could not watch them or when the stimulus person was presented in a pre-recorded video. Importantly, the eye tracking measures showed no differences in participants' looking behavior between these stimulus presentation conditions. The results of facial electromyography responses suggested that direct gaze elicited greater zygomatic and periocular responses than averted gaze did, independent of the presentation condition. It was concluded that the affective arousal and attention-orienting indexing autonomic responses to eye contact are driven by the experience of being watched. In contrast, the facial responses seem to reflect automatized affiliative responses which can be elicited even in conditions in which seeing another's direct gaze does not signal that the self is being watched.
RESUMO
In this study, we analyzed the utility of electromyogram (EMG) signals recorded from the zygomaticus major (zEMG), the trapezius (tEMG), and the corrugator supercilii (cEMG) for emotion detection. We computed eleven-time domain features from the EMG signals to classify the emotions such as amusing, boring, relaxing, and scary. The features were fed to the logistic regression, support vector machine, and multilayer perceptron classifiers, and model performance was evaluated. We achieved an average 10-fold cross-validation classification accuracy of 67.29%. 67.92% and 64.58% by LR using the features extracted from the EMG signals recorded from the zEMG, tEMG, and cEMG, respectively. The classification accuracy improved to 70.6% while combining features from the zEMG and cEMG for the LR model. However, the performance dropped while including the features of EMG from all three locations. Our study shows the importance of utilizing the zEMG and cEMG combination for emotion recognition.
Assuntos
Emoções , Face , Eletromiografia , Modelos Logísticos , MedoRESUMO
Non-suicidal self-injury (NSSI) is an alarming public health concern that is particularly widespread among adolescents. The current study examined affective responses during mother-daughter interactions in adolescent girls with and without a history of NSSI. Participants were 60 girls aged 13-17 with (n = 27) and without (n = 33) a history of NSSI and their mothers. Adolescents and their mothers completed two interaction tasks: one positive and one negative. During these interactions, facial affect was assessed via electromyography (EMG). Results of Actor-Partner Interdependence Modeling (APIM) revealed several intra- and interpersonal disruptions in affect during both tasks among dyads in which the adolescent had an NSSI history. Findings suggest deficits in both self- and co-regulation of facial affect during mother-daughter interactions involving dyads in which the adolescents reports NSSI. Ultimately, if replicated and extended in longitudinal research, these disruptions may prove to be promising targets of intervention to reduce risk for future NSSI in adolescent girls.
Assuntos
Comportamento do Adolescente , Comportamento Autodestrutivo , Feminino , Humanos , Adolescente , Mães/psicologia , Núcleo Familiar , Comportamento Autodestrutivo/psicologia , Comportamento do Adolescente/psicologiaRESUMO
Existing research has offered insight into facial activities and their associations with hedonic liking during the consumption of basic food samples and suggests facial changes during consumption are linked to the hedonic evaluation of tastes and, thus related to the taster's perception rather than the tastes themselves. This study tests whether, during the consumption of commercially available dark chocolate, a complex food product, which can be high in bitterness but expectedly so, how facial activities are linked to the bitterness levels and the hedonic liking of the samples. To do this we carried out two studies with untrained consumers, the first of which captured temporally dynamic sensory perception during the consumption of dark chocolate samples of 36% and 85% cocoa content, using the Temporal Dominance of Sensations (TDS) approach. The second study captured facial EMG over the corrugator and zygomaticus muscles during the consumption of dark chocolate samples (36%, 70%, and 85% cocoa). Specifically, the aim of this research was to investigate whether corrugator activity had a greater association with bitterness perception, linked to cocoa, or hedonic evaluation. Capturing the dynamic sensory profile of chocolate samples allowed an investigation into the time points most evident of sensory variation related to the bitterness and sweetness of the taste, allowing insight into whether facial activities also deviated during this time. These data offer evidence to suggest that corrugator was associated with hedonic evaluation during consumption of the samples, with the most liked samples (being those with 70% and 36% cocoa) eliciting similar corrugator activities and less activity than the least liked 85% cocoa content sample; however, there was also evidence to suggest a significant variation in participants' corrugator activity during the period of oral processing when bitterness was most evident in the 85% cocoa sample and sweetness was most evident in the 36% cocoa sample (i.e., the time when bitterness and sweetness were most divergent) Further investigation showed a variation in facial activities elicited during consumption of the 36% cocoa sample based on whether individuals were part of the group who favoured the 85% cocoa sample or the group favouring the 36% cocoa sample. The findings, therefore, suggest facial EMG, specifically over the corrugator, appears to be related to the hedonic evaluation of a complex food product and not the taste itself. Furthermore, being aware of the time points where sensory variations are most apparent between samples can allow for targeted investigation into facial EMG and its ability to distinguish food samples.
Assuntos
Cacau , Chocolate , Humanos , Eletromiografia , Paladar , Percepção GustatóriaRESUMO
Aversive social experiences are proposed to be a risk factor for developing Social Anxiety Disorder (SAD). Many patients with SAD report associated daily life symptoms, such as intrusive re-experiencing (e.g., negatively distorted images of oneself), avoidance, alterations in cognitions and mood, as well as hyperarousal, resembling symptom dimensions of Posttraumatic Stress Disorder (PTSD). These PTSD-like symptoms may result from maladaptive processing and representation of the aversive social experiences in memory. Emotional hyperreactivity during memory retrieval of aversive social experiences is another feature of SAD which was found in previous studies. This study aimed to further investigate PTSD-like symptoms and emotional reactivity associated with etiologically relevant aversive social experiences and shed more light on a potential relationship between both. Eighty-five patients with SAD and 85 healthy controls (HC) participated in this cross-sectional study. It comprised an imagination task with self-report and physiological measures to assess emotional reactivity during the cued recall of the aversive social experience and clinical interviews to assess PTSD-like symptoms. We expected increased emotional reactivity and more severe PTSD-like symptoms in response to the aversive social experience in patients with SAD compared to HC, as well as a positive correlation between emotional reactivity and PTSD-like symptoms in patients with SAD. Indeed, patients with SAD showed emotional hyperreactivity (self-report, physiology) during the cued recall of the aversive social experiences, also when compared to two control memory conditions (neutral, negative non-social) and HC. Patients with SAD furthermore reported more severe PTSD-like symptoms compared to HC and intrusive re-experiencing symptoms were positively correlated with distress during imagery of the social aversive event in patients with SAD. These results might point toward a maladaptive representation of aversive social experiences in memory. Similar to PTSD, this maladaptive memory representation might promote the development of PTSD-like symptoms such as intrusive re-experiencing (e.g., in the form of intrusive self-images in patients with SAD), which might finally lead to and maintain symptoms of SAD.