Neuropsychological aspects of facial asymmetry during emotional expression: a review of the normal adult literature

Understanding Children's Accuracy in Recognizing Facial Expressions of Pain

Facial expressions of pain have an adaptive function in informing others of the need of attention and care. The detection of these nonverbal cues is particularly important in children since they are not always capable of expressing their needs verbally. Nevertheless, research recurrently shows that distinguishing between genuine, suppressed, and simulated pain expressions produced by children is a difficult task for adults; even when their professions require such a skill (e.g. doctors or nurses). Only a few studies have explored the development of this specific ability amongst children's peers. The current study aims to fill this literature gap by exploring children's ability to recognize and judge genuine, simulated, and suppressed expressions of pain produced by other children their age. Seventy-nine children from kindergarten to fourth grade viewed videos in which children encoders expressed the three aforementioned types of pain while plunging their hand in cold or warm water. Participants were asked to select the type of pain that was expressed. They were also asked their level of confidence in their answer and the level of pain they thought the children were experiencing. Despite having a high level of confidence in their answers, kindergarteners had a significantly lower proportion of correct answers compared to children in third and fourth grade. Furthermore, regardless of their grade level, children were better at recognizing suppressed pain expressions and had lower performance rates for genuine pain recognition. Our overall findings revealed an improvement in children's performance with aging.

Crossing fibers may underlie the dynamic pulling forces of muscles that attach to cartilage at the tip of the nose

The present study used microdissection, histology, and microcomputed tomography (micro-CT) with the aims of determining the prevalence and patterns of the depressor septi nasi (DSN) and orbicularis oris (OOr) muscles attached to the footplate of the medial crus (fMC) of the major alar cartilage, focusing on their crossing fibers. The DSN and OOr attached to the fMC of the major alar cartilage were investigated in 76 samples from 38 embalmed Korean adult cadavers (20 males, 18 females; mean age 70 years). The DSN, OOr, or both were attached to the fMC. When the DSN ran unilaterally or was absent, some OOr fibers ascended to attach to the fMC instead of the DSN in 20.6% of the samples. Crossing fibers of the DSN or OOr attached to the fMC were found in 82.4% of the samples. Bilateral and unilateral crossing fibers were found in 32.4% and 50.0%, respectively, and no crossing fibers were found in 17.6%. The DSN and OOr that attached to the fMC could be categorized into six types according to presence of the DSN and the crossing patterns of the DSN and OOr. Anatomical findings of the DSN and OOr that attached to the fMC were confirmed in histology and micro-CT images. These findings offer insights on anatomical mechanisms that may underlie the dynamic pulling forces generated by muscles that attach to the fMCs and on evolutionary variation observed in human facial expressions. They can also provide useful information for guiding rhinoplasty of the nasal tip.

Social gaze in preterm infants may act as an early indicator of atypical lateralization

Visual field biases have been identified as markers of atypical lateralization in children with developmental conditions, but this is the first investigation to consider early lateralized gaze behaviors for social stimuli in preterm infants. Eye-tracking methods with 51 preterm (33 male, 92.1% White) and 61 term-born (31 male, 90.1% White) infants aged 8-10 months from Edinburgh, UK, captured the development of visual field biases, comparing gaze behavior to social and non-social stimuli on the left versus right of the screen. Preterm infants showed a significantly reduced interest to social stimuli on the left versus right compared to term children (d = .58). Preterm children exhibit early differential orienting preferences that may be an early indicator of atypical lateralized function.

The Intricate Web of Asymmetric Processing of Social Stimuli in Humans

Although the population-level preference for the use of the right hand is the clearest example of behavioral lateralization, it represents only the best-known instance of a variety of functional asymmetries observable in humans. What is interesting is that many of such asymmetries emerge during the processing of social stimuli, as often occurs in the case of human bodies, faces and voices. In the present paper, after reviewing previous literature about human functional asymmetries for social and emotional stimuli, we suggest some possible links among them and stress the necessity of a comprehensive account (in both ontogenetic and phylogenetic terms) for these not yet fully explained phenomena. In particular, we propose that the advantages of lateralization for emotion processing should be considered in light of previous suggestions that (i) functional hemispheric specialization enhances cognitive capacity and efficiency, and (ii) the alignment (at the population level) of the direction of behavioral asymmetries emerges, under social pressures, as an evolutionary stable strategy.

Symmetric in the striate but asymmetric in the extrastriate cortex when processing three-quarter faces: Neural underpinnings for aesthetic appreciations

Faces and their aesthetic appreciation are a core element of social interaction. Although studies have been made on facial processing when looking at faces with different perspectives, a direct comparison of faces in the left to the right perspective is missing. Portraits in classical Western art indicate a preference of the left compared to the right perspective, but the neural underpinnings of such an asymmetry still have to be clarified. Using functional magnetic resonance imaging, the current study focuses on the processing of three-quarter faces seen with different perspectives. Seventeen participants were asked to passively look at photographs of six male and six female faces with a neutral expression; the photographs were taken from the left, right, and frontal perspectives while keeping their focus on the eyes. The results showed that specific brain areas were involved in processing the three-quarter faces in either symmetric or asymmetric ways. Viewing left and right three-quarter faces resulted in two mirror-like activations in the striate cortex corresponding to the symmetric layout of the left and right perspectives. Viewing the left face resulted additionally in an enhanced activation also in the left extrastriate cortex. The right perspective of male faces elicited a lower activation compared to other perspectives in face-selective areas of the brain. Our findings suggest that the preference of the left three-quarter face emerges already in the early visual pathway presumably prior to facial identification, emotional processing, and aesthetic appreciation. Our observations may have general importance in disentangling different neural components and processing stages in the spatiotemporal characteristics of artistic expressions.

The Influence of Facial Asymmetry on Genuineness Judgment

This study investigates how asymmetry, expressed emotion, and sex of the expresser impact the perception of emotional facial expressions (EFEs) in terms of perceived genuineness. Thirty-five undergraduate women completed a task using chimeric stimuli with artificial human faces. They were required to judge whether the expressed emotion was genuinely felt. The results revealed that (a) symmetrical faces are judged as more genuine than asymmetrical faces and (b) EFEs' decoding is modulated by complex interplays between emotion and sex of the expresser.

Differential Hemispheric Lateralization of Emotions and Related Display Behaviors: Emotion-Type Hypothesis

There are two well-known hypotheses regarding hemispheric lateralization of emotions. The Right Hemisphere Hypothesis (RHH) postulates that emotions and associated display behaviors are a dominant and lateralized function of the right hemisphere. The Valence Hypothesis (VH) posits that negative emotions and related display behaviors are modulated by the right hemisphere and positive emotions and related display behaviors are modulated by the left hemisphere. Although both the RHH and VH are supported by extensive research data, they are mutually exclusive, suggesting that there may be a missing factor in play that may provide a more accurate description of how emotions are lateralization in the brain. Evidence will be presented that provides a much broader perspective of emotions by embracing the concept that emotions can be classified into primary and social types and that hemispheric lateralization is better explained by the Emotion-type Hypothesis (ETH). The ETH posits that primary emotions and related display behaviors are modulated by the right hemisphere and social emotions and related display behaviors are modulated by the left hemisphere.

Changes in Computer-Analyzed Facial Expressions with Age

Facial expressions are well known to change with age, but the quantitative properties of facial aging remain unclear. In the present study, we investigated the differences in the intensity of facial expressions between older (n = 56) and younger adults (n = 113). In laboratory experiments, the posed facial expressions of the participants were obtained based on six basic emotions and neutral facial expression stimuli, and the intensities of their faces were analyzed using a computer vision tool, OpenFace software. Our results showed that the older adults expressed strong expressions for some negative emotions and neutral faces. Furthermore, when making facial expressions, older adults used more face muscles than younger adults across the emotions. These results may help to understand the characteristics of facial expressions in aging and can provide empirical evidence for other fields regarding facial recognition.

Mood and emotional disorders associated with parkinsonism, Huntington disease, and other movement disorders

This chapter provides a review of mood, emotional disorders, and emotion processing deficits associated with diseases that cause movement disorders, including Parkinson's disease, Lewy body dementia, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, frontotemporal dementia with parkinsonism, Huntington's disease, essential tremor, dystonia, and tardive dyskinesia. For each disorder, a clinical description of the common signs and symptoms, disease progression, and epidemiology is provided. Then the mood and emotional disorders associated with each of these diseases are described and discussed in terms of clinical presentation, incidence, prevalence, and alterations in quality of life. Alterations of emotion communication, such as affective speech prosody and facial emotional expression, associated with these disorders are also discussed. In addition, if applicable, deficits in gestural and lexical/verbal emotion are reviewed. Throughout the chapter, the relationships among mood and emotional disorders, alterations of emotional experiences, social communication, and quality of life, as well as treatment, are emphasized.

Keep a Left Profile, Baby! The Left-Cradling Bias Is Associated with a Preference for Left-Facing Profiles of Human Babies

The left-cradling bias (LCB) refers to the (typically female) preference to hold an infant on the left side of one’s own body. Among the three main accounts proposed for such a phenomenon, namely the “handedness”, “heartbeat” and “hemispheric asymmetry” hypotheses, the latter has met with the greatest empirical success. Accordingly, the LCB would facilitate the communication of socio-emotional information through the right hemisphere of both the cradled and the cradling individual, and should emerge mainly in face-to-face interactions. In this regard, it should be noticed that when the infant’s body is oriented toward the cradler, the left or right side of their face is relatively more visible to left- and right-cradlers, respectively. Therefore, we hypothesized that the LCB might also be associated with a preference for left-facing profiles (i.e., those showing the left, and more expressive, hemiface/cheek) of human babies. In order to test our hypothesis, we assessed the cradling-side preferences of female participants, as well as their preference for the left- or right-facing profile of a human infant depicted in a drawing. Left-cradlers exhibited a significantly larger preference for the left-facing version of the drawing compared with right-cradlers, a finding further corroborating the right-hemisphere hypothesis.

A closer look at the paralyzed face; a narrative review of the neurobiological basis for functional and aesthetic appreciation between patients with a left and a right peripheral facial palsy

BACKGROUND

The facial nerve or n. facialis (NVII) is the seventh cranial nerve and it is responsible for the innervation of the mimic muscles, the gustatory organ, and the secretomotor function to the salivary, lacrimal, nasal and palatine glands. Clinical presentation of Facial Palsy (FP) is characterized by unilateral facial asymmetry and may present with a change in taste, decreased saliva production, and dysarthria. A facial palsy has a notable effect on the facial appreciation by both the patient and the environment and also affects quality of life and emotional processing. There appear to be differences in the appreciation of people with a left and right facial palsy.

PURPOSE OF THIS REVIEW

The purpose of the review is to give an overview of the anatomy of the facial nerve, neuro-anatomy of face processing, and hemispheric specialization and lateralization. Further,an overview is given of the clinical studies that translated the neuro-anatomical and neurobiological basis of these concepts into clinical studies. What this review adds: This review emphasizes the neurobiological evidence of differences in face processing between the left and right cerebral hemisphere, wherein it seems that the right hemisphere is superior in emotional processing. Several theories are proposed; 1) a familiarity hypothesis and 2) a left-right hemispheric specialization hypothesis. In clinical studies, promising evidence might indicate that, in patients with FP, there is indeed a difference in how left and right FP are perceived. This might give differences in decreased quality of life and finally in occurrence of depression. Further research must aim to substantiate these findings and determine the need for altering the standard therapeutic advice given to patients.

White matter correlates of hemi-face dominance in happy and sad expression

The neural underpinnings of human emotional expression are thought to be unevenly distributed among the two brain hemispheres. However, little is known on the anatomy supporting this claim, particularly in the cerebral white matter. Here, we explored the relationship between hemi-face dominance in emotional expression and cerebral white matter asymmetries in 33 healthy participants. Measures of emotional expression were derived from pictures of the participant's faces in a 'happy smiling' and a 'sad frowning' conditions. Chimeric faces were constructed by mirroring right and left hemi-faces, as done in previous studies, resulting in a left mirrored and right mirrored chimeric face per picture. To gain measures of hemi-face dominance per participant, a jury of 20 additional participants rated which chimeric face shows the higher intensity of emotional expressivity, by marking a 155 mm line between the two versions. Measures of the asymmetry of the uncinate, the cingulum and the three branches of superior longitudinal fasciculi were derived from diffusion-weighted imaging tractography dissections. Group effect analyses indicated that the degree of asymmetry in emotional expression was not as prominent as reported in the literature and showed a large inter-individual variability. The degree of asymmetry in emotional expression was, however, significantly associated with the asymmetries in connective properties of the fronto-temporal and fronto-parietal tracts, specifically the uncinate fasciculus and the first branch of the superior longitudinal fasciculus. Therefore, this result raises novel hypotheses on the relationship of specific white matter tracts and emotional expression, especially their role in mood disorders.

Differences in Facial Expressions between Spontaneous and Posed Smiles: Automated Method by Action Units and Three-Dimensional Facial Landmarks

Research on emotion recognition from facial expressions has found evidence of different muscle movements between genuine and posed smiles. To further confirm discrete movement intensities of each facial segment, we explored differences in facial expressions between spontaneous and posed smiles with three-dimensional facial landmarks. Advanced machine analysis was adopted to measure changes in the dynamics of 68 segmented facial regions. A total of 57 normal adults (19 men, 38 women) who displayed adequate posed and spontaneous facial expressions for happiness were included in the analyses. The results indicate that spontaneous smiles have higher intensities for upper face than lower face. On the other hand, posed smiles showed higher intensities in the lower part of the face. Furthermore, the 3D facial landmark technique revealed that the left eyebrow displayed stronger intensity during spontaneous smiles than the right eyebrow. These findings suggest a potential application of landmark based emotion recognition that spontaneous smiles can be distinguished from posed smiles via measuring relative intensities between the upper and lower face with a focus on left-sided asymmetry in the upper region.

Orienting asymmetries and physiological reactivity in dogs' response to human emotional faces

Recent scientific literature shows that emotional cues conveyed by human vocalizations and odours are processed in an asymmetrical way by the canine brain. In the present study, during feeding behaviour, dogs were suddenly presented with 2-D stimuli depicting human faces expressing the Ekman's six basic emotion (e.g. anger, fear, happiness, sadness, surprise, disgust, and neutral), simultaneously into the left and right visual hemifields. A bias to turn the head towards the left (right hemisphere) rather than the right side was observed with human faces expressing anger, fear, and happiness emotions, but an opposite bias (left hemisphere) was observed with human faces expressing surprise. Furthermore, dogs displayed higher behavioural and cardiac activity to picture of human faces expressing clear arousal emotional state. Overall, results demonstrated that dogs are sensitive to emotional cues conveyed by human faces, supporting the existence of an asymmetrical emotional modulation of the canine brain to process basic human emotions.

A historical review of investigations on laterality of emotions in the human brain

Different models of emotional lateralization, advanced since the first clinical observations raised this issue, will be reviewed following their historical progression. The clinical investigations that have suggested a general dominance of the right hemisphere for all kinds of emotions and the experimental studies that have proposed a different hemispheric specialization for positive vs. negative emotions (valence hypothesis) or for approach vs. withdrawal tendencies (motivational hypothesis) will be reviewed first and extensively. This historical review will be followed by a short discussion of recent anatomo-clinical and activation studies that have investigated (a) emotional and behavioral disorders of patients with asymmetrical forms of fronto-temporal degeneration and (b) laterality effects in specific brain structures (amygdala, ventro-medial prefrontal cortex, and anterior insula) playing a critical role in different components of emotions. Overall, these studies support the hypothesis of a right hemisphere dominance for all components of the emotional system.

Emotions and the Right Hemisphere: Can New Data Clarify Old Models?

Models advanced to explain hemispheric asymmetries in representation of emotions will be discussed following their historical progression. First, the clinical observations that have suggested a general dominance of the right hemisphere for all kinds of emotions will be reviewed. Then the experimental investigations that have led to proposal of a different hemispheric specialization for positive versus negative emotions (valence hypothesis) or, alternatively, for approach versus avoidance tendencies (motivational hypothesis) will be surveyed. The discussion of these general models will be followed by a review of recent studies which have documented laterality effects within specific brain structures, known to play a critical role in different components of emotions, namely the amygdata in the computation of emotionally laden stimuli, the ventromedial prefrontal cortex in the integration between cognition and emotion and in the control of impulsive reactions and the anterior insula in the conscious experience of emotion. Results of these recent investigations support and provide an updated integrated version of early models assuming a general right hemisphere dominance for all kinds of emotions.

Test-retest reliability of smile tasks using three-dimensional facial topography

OBJECTIVES

To evaluate the test-retest reliability of three types of facial expression tasks using three-dimensional (3D) facial topography.

MATERIALS AND METHODS

Twelve adult volunteers were enrolled in this study. They were instructed to perform three different facial expression tasks: rest posture, posed smile, and maximum effort smile. Each task was recorded using a 3D image-capturing device on two separate occasions with an interval of 1 week between sessions. The images of two sessions were superimposed based on the forehead. For each participant and for each facial expression, a wire mesh fitting was conducted. This method generated 6,017 points on the wire mesh. Intraindividual reliability between sessions for each task was statistically tested by intraclass correlation coefficients (ICCs) and the 95% confidence interval minimal detectable change (MDC₉₅).

RESULTS

The MDC₉₅ for the repeated measures of the rest posture, posed smile, and maximum effort smile exhibited means of 0.8, 1.5, and 1.3 mm, respectively, on the z-axis. The ICCs ranged from substantial to almost perfect agreement for repeated measures for the rest posture and maximum effort smile (0.60 < ICC ≤ 1.00). The right corner of the mouth in the posed smile showed moderate agreement (0.40 < ICC ≤ 0.60).

CONCLUSIONS

The overall test-retest reliability of the maximum effort smile and rest posture showed substantial to almost perfect agreement, and this was clinically acceptable.

The use of the Duchenne marker and symmetry of the expression in the judgment of smiles in schizophrenia

Research has recurrently shown that individuals with schizophrenia have impairments in emotional facial recognition and this deficit has been associated with aberrant visual scanning of the face. Because human beings have the ability to control the expression of emotion, the communication process becomes more complex. The goal of the current study was to conduct a systematic examination of the response pattern and perceptual-attentional processing in distinguishing smiles with the presence and absence of the Duchenne marker and symmetry and asymmetry of the activation in individuals with schizophrenia. Sixteen individuals diagnosed with schizophrenia and 16 control individuals were asked to judge whether the smiles were really happy or not. Individuals with schizophrenia produced fewer expected responses than controls in judging the symmetric non-Duchenne smile as not really happy. In addition, like their healthy counterparts, individuals with schizophrenia showed difficulty with the judgement of asymmetric Duchenne smiles. In addition to not being as sensitive to the cues, individuals with schizophrenia show differences in their viewing patterns. While the current study does not provide clear links between these viewing patterns and judgment responses, future research should explore other explanations, such as explicit knowledge, for the differences in results.

Discriminative Thresholds in Facial Asymmetry: A Review of the Literature

Background

Facial symmetry is intimately correlated with attractiveness. Perfect facial symmetry is disconcerting and a degree of facial asymmetry is considered normal. There is a lack of data on the limits of normality across facial subunits.

Objectives

This systematic review aims to establish categories of facial asymmetry perception for facial aesthetic units by establishing a discriminative threshold of "deformity perception" across facial subunits and a threshold for intervention (unacceptable asymmetry).

Methods

A review of the literature was performed across Medline and Embase databases using OvidSP. All prospective studies evaluating the perception of progressive facial asymmetry in laymen or clinicians using a two- or three-dimensional model were included. Studies that did not evaluate rates of perception at varying degrees of asymmetry were excluded as these did not allow for the identification of a perceptive threshold.

Results

Each facial feature possesses a unique threshold of perception defined by an abrupt, statistically significant increase in detection. Asymmetry of the eyelid position at rest is the most sensitive facial feature (perceptive threshold, 2 mm) (P < 0.02). This is followed by deviations of the oral commissure (3 mm) (P < 0.001), brow position (3.5 mm) (P < 0.001), nasal tip deviation (4 mm) (P < 0.001), and chin deviation (6 mm) (P < 0.001). Desire for surgery for worsening deformities beyond the intervention threshold is characterized by an exponential, rather than linear, correlation.

Conclusions

Categories of facial asymmetry perception establish a framework to counsel patients with facial asymmetries, and are a valuable adjunct to clinical judgment in the management of static and dynamic facial deformities.

Cortical control of facial expression

The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system.

Study of Posed Emotion in Facial EMG Asymmetry

37 subjects' facial electromyographic activity at the corrugator and zygomatic muscle regions were recorded while they were posing with happy and sad facial expressions. Analysis showed that the mean value of EMG activity at the left zygomatic muscle region was the highest, followed by the right zygomatic, left corrugator, and right corrugator muscle regions, while a happy facial expression was posed. The mean value of EMG activity at the left corrugator muscle region was the highest, followed by those for the right corrugator, left zygomatic, and right zygomatic muscle regions while a sad facial expression was posed. Further analysis indicated that the power of facial EMG activity on the left side of the face was stronger than on the right side of the face while posing both happy and sad expressions.

Effects of Viewing Pleasant and Unpleasant Photographs on Facial EMG Asymmetry

40 subjects' facial electromyographic (EMG) activity at the corrugator and zygomatic muscle regions were recorded while they were viewing pleasant and unpleasant photographs. Analysis showed that the EMG activity at the left zygomatic muscle region generated the highest power, followed by the right zygomatic, left corrugator, and right corrugator muscle regions, while viewing pleasant photographs. The EMG activity at the left corrugator muscle region generated the highest power, followed by the right corrugator, left zygomatic, and right zygomatic muscle regions, while viewing unpleasant photographs. Further statistical analysis indicated that the EMG activities at the left corrugator region generated significantly higher power than those at the right corrugator region while viewing unpleasant photographs. It was concluded that the intensity of facial EMG activity on the left side of the face was stronger than the right side of the face during the process of emotional expression.

Brain Lateralization of Emotional Processing: Historical Roots and a Future Incorporating “Dominance”

This article provides a review of research on the hemispheric specialization in emotional processing during the past 40 years and the theoretical models derived from the conceptual analysis of these results. The publications reviewed here were collected to better appreciate the cortical lateralization of emotional perception (visual and auditory), expression (facial and prosodic), and experience. Four major models of emotional processing are discussed—the Right Hemisphere, Valence, Approach-Withdrawal, and Behavioral Inhibition System–Behavioral Activation System models. Observing the relative merits and limitations of these models, a new direction for exploration is offered. Specifically, to better appreciate the strength and direction (i.e., approach versus withdrawal) of experienced emotions, it is recommended that state “dominance” be evaluated in the context of asymmetrical activation of left-frontal (dominance) versus right-frontal (submission) brain regions.

Alexithymia is associated with attenuated automatic brain response to facial emotion in clinical depression

BACKGROUND

Alexithymia is a clinically relevant personality trait related to difficulties in recognizing and describing emotions. Previous studies examining the neural correlates of alexithymia have shown mainly decreased response of several brain areas during emotion processing in healthy samples and patients suffering from autism or post-traumatic stress disorder. In the present study, we examined the effect of alexithymia on automatic brain reactivity to negative and positive facial expressions in clinical depression.

METHODS

Brain activation in response to sad, happy, neutral, and no facial expression (presented for 33 ms and masked by neutral faces) was measured by functional magnetic resonance imaging at 3 T in 26 alexithymic and 26 non-alexithymic patients with major depression.

RESULTS

Alexithymic patients manifested less activation in response to masked sad and happy (compared to neutral) faces in right frontal regions and right caudate nuclei than non-alexithymic patients.

CONCLUSIONS

Our neuroimaging study provides evidence that the personality trait alexithymia has a modulating effect on automatic emotion processing in clinical depression. Our findings support the idea that alexithymia could be associated with functional deficits of the right hemisphere. Future research on the neural substrates of emotion processing in depression should assess and control alexithymia in their analyses.

Health-related quality of life in 794 patients with a peripheral facial palsy using the FaCE Scale: a retrospective cohort study

OBJECTIVES

To describe the health-related quality of life of patients visiting a tertiary referral centre for facial palsy, and to analyse factors associated with health-related quality of life, using the FaCE Scale instrument.

DESIGN

Retrospective cohort study.

SETTING

The Facial Nerve Center at the Massachusetts Eye and Ear Infirmary, a tertiary referral centre.

PARTICIPANTS

Patients with a peripheral facial palsy visiting the centre for an initial consultation between August 2007 and June 2012.

MAIN OUTCOME MEASURES

The total FaCE score and the FaCE social function subdomain. Multiple regression models were developed to identify factors associated with the total FaCE score and FaCE social function score.

RESULTS

A total of 794 patients with a mean age of 47.0 ± 16.0 years were analysed in this study, of which 59.9% were female. The mean House-Brackmann, Sunnybrook, total FaCE and FaCE social function scores were 3.6 ± 1.5, 48.2 ± 21.2, 47.3 ± 19.3 and 55.5 ± 19.2, respectively. Increasing age (r = -0.229, P < 0.001) was associated with a lower total FaCE score. Female gender (r = -4.422, P = 0.033) and increased duration of palsy (r = -0.018, P = 0.041) were associated with lower FaCE social function scores.

CONCLUSIONS

While counselling patients on what to expect during the recovery process after facial paralysis is an important part of any clinical visit, FaCE score correlations suggest that female patients with chronic facial palsy and increased age constitute a patient category that may require additional time and attention to prevent or mitigate psychosocial dysfunction.

Gaze Dynamics in the Recognition of Facial Expressions of Emotion

We studied preferably fixated parts and features of human face in the process of recognition of facial expressions of emotion. Photographs of facial expressions were used. Participants were to categorize these as basic emotions; during this process, eye movements were registered. It was found that variation in the intensity of an expression is mirrored in accuracy of emotion recognition; it was also reflected by several indices of oculomotor function: duration of inspection of certain areas of the face, its upper and bottom or right parts, right and left sides; location, number and duration of fixations, viewing trajectory. In particular, for low-intensity expressions, right side of the face was found to be attended predominantly (right-side dominance); the right-side dominance effect, was, however, absent for expressions of high intensity. For both low- and high-intensity expressions, upper face part was predominantly fixated, though with greater fixation of high-intensity expressions. The majority of trials (70%), in line with findings in previous studies, revealed a V-shaped pattern of inspection trajectory. No relationship, between accuracy of recognition of emotional expressions, was found, though, with either location and duration of fixations or pattern of gaze directedness in the face.

Right-lateralized unconscious, but not conscious, processing of affective environmental sounds

Much research on the laterality of affective auditory stimuli features emotional speech. However, environmental sounds can also carry affective information, but their lateralized processing for affect has been studied much less. We studied this in 2 experiments. In Experiment 1 we explored whether the detection of affective environmental sounds (from International Affective Digital Sounds) that appeared in auditory scenes was lateralized. While we found that negative targets were detected more rapidly, detection latencies were the same on the left and right. In Experiment 2 we examined whether conscious appraisal of the stimulus was needed for lateralization patterns to emerge, and asked participants to rate the stimuli's pleasantness in a dichotic listening test. This showed that when positive/negative environmental sounds were in the attended to-be-rated channel, ratings were the same regardless of laterality. However, when participants rated neutral stimuli and the unattended channel was positive/negative, the valence of the unattended channel affected the neutral ratings more strongly with left ear (right hemisphere, RH) processing of the affective sound. We link our findings to previous work that suggests that the RH may specialize in the unconscious processing of emotion via subcortical routes.

Cortical and Subcortical Substrates of Cranial Nerve Function

The pivotal role of cranial nerves in a wholesome life experience cannot be overemphasized. Research has opened new avenues to understand cranial nerve function. Classical concept of strict bilateral cortical control of cranial nerves has given way to concepts of hemispheric dominance and hemispheric lateralization. An astute Neuroradiologist should keep abreast of these concepts and help patients and referring physicians by applying this knowledge in reading images. This chapter provides an overview of cranial nerve function and latest concepts pertaining to their cortical and subcortical control.

The dynamic opponent relativity model: an integration and extension of capacity theory and existing theoretical perspectives on the neuropsychology of arousal and emotion

Arousal theory as discussed within the present paper refers to those mechanisms and neural systems involved in central nervous system activation and more specifically the systems involved in cortical activation. Historical progress in the evolution of arousal theory has led to a better understanding of the functional neural systems involved in arousal or activation processes and ultimately contributed much to our current theories of emotion. Despite evidence for the dynamic interplay between the left and right cerebral hemispheres, the concepts of cerebral balance and dynamic activation have been emphasized in the neuropsychological literature. A conceptual model is proposed herein that incorporates the unique contributions from multiple neuropsychological theories of arousal and emotion. It is argued that the cerebral hemispheres may play oppositional roles in emotion partially due to the differences in their functional specializations and in their persistence upon activation. In the presence of a threat or provocation, the right hemisphere may activate survival relevant responses partially derived from hemispheric specializations in arousal and emotional processing, including the mobilization of sympathetic drive to promote heightened blood pressure, heart rate, glucose mobilization and respiratory support necessary for the challenge. Oppositional processes and mechanisms are discussed, which may be relevant to the regulatory control over the survival response; however, the capacity of these systems is necessarily limited. A limited capacity mechanism is proposed, which is familiar within other physiological systems, including that providing for the prevention of muscular damage under exceptional demand. This capacity theory is proposed, wherein a link may be expected between exceptional stress within a neural system and damage to the neural system. These mechanisms are proposed to be relevant to emotion and emotional disorders. Discussion is provided on the possible role of currently applied therapeutic interventions for emotional disorders.

An assessment of sexual dimorphism in relation to facial asymmetry in esthetically pleasing faces

Objective:

The aim of the study is to detect gender-wise difference in the skeletal asymmetry in the esthetically pleasing faces.

Materials and methods:

a cross sectional study was conducted on 25 females and 25 males of age 18 -25 years using the posterior-anterior cephalograms. The selected part of grummon’s frontal analysis for analyzing the vertical skeletal asymmetries, mandibular morphology, transverse asymmetry and mandibular deviation was used. The obtained data was subjected to independent student’s‘t’ test for comparing the difference between males and females.

Results:

there was statistically significant difference between the males and females for the measurements like Gonion-Menton length for the mandibular morphology and for the transverse parameters like zygomatico frontal suture length, jular length and antegonial notch length. There was no significant difference for the sidedness of asymmetry for the males and females.

Conclusion:

frontal facial asymmetry showed sexual dimorphism with males showing greater asymmetric values than the females. The asymmetry showed right sided prominence for both the males and females. This knowledge can be utilized for planning facial reconstruction and remodeling surgeries.

On facial asymmetry and self-perception

Self-perception has been an enduring human concern since ancient times and remains a significant component of the preoperative and postoperative consultation. Despite modern technological attempts to reproduce the first-hand experience, there is no perfect substitute for human, stereoscopic, three-dimensional vision in evaluating appearance. Nowadays, however, the primary tools available to a patient for examining his or her own appearance, particularly the face, are photographs and mirrors. Patients are often unaware of how cameras and photographs can distort and degrade image quality, leading to an inaccurate representation of true appearance. Everyone knows that mirrors reverse an image, left and right, and most people recognize their own natural facial asymmetry at some level. However, few realize that emotions are not only expressed unequally by the left and right sides of the face but also perceived unequally by others. The impact and effect of this "facedness" is completely reversed by mirrors, potentially creating a significant discrepancy between what a patient perceives of himself or herself and what the surgeon or other third party sees. This article ties together the diverse threads leading to this problem and suggests several ways of mitigating the issue through technology and patient counseling.

Electrophysiological analysis of the affective congruence between pattern regularity and word valence

Reflection symmetry is an important property of human designs and biological organisms, and it is often judged to be beautiful. Previous reaction-time based studies have shown a congruency effect, where reflection symmetry facilitates processing of positive words, and random patterns facilitate negative words. But what is the neural basis of affective responses to symmetry? In Experiment 1 we recorded ERPs from posterior electrode clusters while participants viewed reflection or random patterns with either a positive or negative word superimposed. In the Discriminate Regularity task, participants categorized the patterns (reflection or random). In the Discriminate Word task, they categorized the words as positive or negative. In Experiment 2, participants classified words and patterns on each trial. We found a difference between ERP waves from congruent (reflection with positive word, random with negative word) and incongruent trials (reflection with negative, random with positive). This congruency effect began around 200 ms, and persisted up to 1,000 ms post stimulus, and was only present in the Discriminate Word task. We suggest that when evaluating words, participants automatically evaluate the background pattern as well, and this alters early visual processing.

Pupil dilations reflect why rembrandt biased female portraits leftward and males rightward

Portrait painters are experts at examining faces and since emotional content may be expressed differently on each side of the face, consider that Rembrandt biased his male portraits to show their right-cheek more often and female portraits to show their left-cheek more often. This raises questions regarding the emotional significance of such biased positions. I presented rightward and leftward facing male and female portraits. I measured observers’ pupil size while asking observers to report how (dis)pleasing they found each image. This was a methodological improvement over the type of research initially done by Eckhard Hess who claimed that pupils dilate to pleasant images and constrict to unpleasant images. His work was confounded since his images’ luminances and contrasts across conditions were inconsistent potentially affecting pupil size. To overcome this limitation I presented rightward or leftward facing male and female portraits by Rembrandt to observers in either their original or mirror-reversed position. I found that in viewing male portraits pupil diameter was a function of arousal. That is, larger pupil diameter occurred for images rated both low and high in pleasantness. This was not the case with female portraits. I discuss these findings in regard to the perceived dominance of males and how emotional expressions may be driven by hemispheric laterality.

The facial motor system

Facial movements support a variety of functions in human behavior. They participate in automatic somatic and visceral motor programs, they are essential in producing communicative displays of affective states and they are also subject to voluntary control. The multiplicity of functions of facial muscles, compared to limb muscles, is reflected in the heterogeneity of their anatomical and histological characteristics that goes well beyond the conventional classification in single facial muscles. Such parcellation in different functional muscular units is maintained throughout the central representation of facial movements from the brainstem up to the neocortex. Facial movements peculiarly lack a conventional proprioceptive feedback system, which is only in part vicariated by cutaneous or auditory afferents. Facial motor activity is the main marker of endogenous affective states and of the affective valence of external stimuli. At the cortical level, a complex network of specialized motor areas supports voluntary facial movements and, differently from upper limb movements, in such network there does not seem to be a prime actor in the primary motor cortex.

Importance of the brow in facial expressiveness during human communication

OBJECTIVE

The objective of this study was to evaluate laterality and upper/lower face dominance of expressiveness during prescribed speech using a unique validated image subtraction system capable of sensitive and reliable measurement of facial surface deformation.

RATIONALE

Observations and experiments of central control of facial expressions during speech and social utterances in humans and animals suggest that the right mouth moves more than the left during nonemotional speech. However, proficient lip readers seem to attend to the whole face to interpret meaning from expressed facial cues, also implicating a horizontal (upper face-lower face) axis.

STUDY DESIGN

Prospective experimental design. Experimental maneuver: recited speech.

OUTCOME MEASURE

image-subtraction strength-duration curve amplitude.

METHODS

Thirty normal human adults were evaluated during memorized nonemotional recitation of 2 short sentences. Facial movements were assessed using a video-image subtractions system capable of simultaneously measuring upper and lower specific areas of each hemiface.

RESULTS

The results demonstrate both axes influence facial expressiveness in human communication; however, the horizontal axis (upper versus lower face) would appear dominant, especially during what would appear to be spontaneous breakthrough unplanned expressiveness.

CONCLUSION

These data are congruent with the concept that the left cerebral hemisphere has control over nonemotionally stimulated speech; however, the multisynaptic brainstem extrapyramidal pathways may override hemiface laterality and preferentially take control of the upper face. Additionally, these data demonstrate the importance of the often-ignored brow in facial expressiveness.

LEVEL OF EVIDENCE

Experimental study. EBM levels not applicable.

Decoding facial blends of emotion: visual field, attentional and hemispheric biases

Most clinical research assumes that modulation of facial expressions is lateralized predominantly across the right-left hemiface. However, social psychological research suggests that facial expressions are organized predominantly across the upper-lower face. Because humans learn to cognitively control facial expression for social purposes, the lower face may display a false emotion, typically a smile, to enable approach behavior. In contrast, the upper face may leak a person's true feeling state by producing a brief facial blend of emotion, i.e. a different emotion on the upper versus lower face. Previous studies from our laboratory have shown that upper facial emotions are processed preferentially by the right hemisphere under conditions of directed attention if facial blends of emotion are presented tachistoscopically to the mid left and right visual fields. This paper explores how facial blends are processed within the four visual quadrants. The results, combined with our previous research, demonstrate that lower more so than upper facial emotions are perceived best when presented to the viewer's left and right visual fields just above the horizontal axis. Upper facial emotions are perceived best when presented to the viewer's left visual field just above the horizontal axis under conditions of directed attention. Thus, by gazing at a person's left ear, which also avoids the social stigma of eye-to-eye contact, one's ability to decode facial expressions should be enhanced.

Analysis of eye movements in the judgment of enjoyment and non-enjoyment smiles

Enjoyment smiles are more often associated with the simultaneous presence of the Cheek raiser and Lip corner puller action units, and these units' activation is more often symmetric. Research on the judgment of smiles indicated that individuals are sensitive to these types of indices, but it also suggested that their ability to perceive these specific indices might be limited. The goal of the current study was to examine perceptual-attentional processing of smiles by using eye movement recording in a smile judgment task. Participants were presented with three types of smiles: a symmetric Duchenne, a non-Duchenne, and an asymmetric smile. Results revealed that the Duchenne smiles were judged happier than those with characteristics of non-enjoyment. Asymmetric smiles were also judged happier than the non-Duchenne smiles. Participants were as effective in judging the latter smiles as not really happy as they were in judging the symmetric Duchenne smiles as happy. Furthermore, they did not spend more time looking at the eyes or mouth regardless of types of smiles. While participants made more saccades between each side of the face for the asymmetric smiles than the symmetric ones, they judged the asymmetric smiles more often as really happy than not really happy. Thus, processing of these indices do not seem limited to perceptual-attentional difficulties as reflected in viewing behavior.

The silent social/emotional signals in left and right cheek poses: a literature review

When posing for a painted or photographic portrait, people are more likely to offer their left, rather than right, cheek (e.g., the Mona Lisa). Why? This paper reviews research investigating the left cheek bias, and the reasons underlying this posing asymmetry. Ruling out mechanical and perceptual biases, the paper focuses on the silent emotional and social signals conveyed by left and right cheek poses, demonstrating that people intuitively offer the left cheek to express emotion and perceive left cheek poses as more emotional. Moreover, because the left cheek appears more emotionally expressive, we unconsciously use cheek shown as a cue when presenting or determining academic specialisation, scientific standing, and even political affiliation. The research is consistent in suggesting that something as subtle as a 15° head turn implicitly influences others' perceptions: if you want to be perceived as open and creative, rather than dry and scientific, it might be time to turn the other cheek.

Neurological and psychiatric aspects of emotion

Neurological and psychiatric aspects of emotions have been the focus of intense research for the past 30 years. Studies in both acute (e.g., stroke, traumatic brain injury (TBI)) and chronic (e.g., dementia, Parkinson's disease) neurological disorders demonstrated a high frequency of both depression and apathy. Studies in stroke and TBI reported a significant association between lesion location and depression. Both depression and apathy are significant predictors of poor recovery among patients with brain injuries, and of steeper cognitive and functional decline among patients with neurodegenerative disorders. Poor insight and judgment are frequently found among patients with brain injury or degeneration. There is increasing evidence that damage to specific brain regions, such as the ventromedial prefrontal cortex, is associated with inappropriate emotional reactions in social contexts and diminished anxiety and concern for the future. In severe cases, behavioural changes may also include poor decision-making in the social realm, deficits in goal-directed behavior, and lack of insight into these changes. Future studies will validate specific diagnostic criteria for the various cognitive, emotional, and behavioral problems reported among patients with neurological disorders, which may result in more specific and effective treatments.

Contrast of hemispheric lateralization for oro-facial movements between learned attention-getting sounds and species-typical vocalizations in chimpanzees: extension in a second colony

Studies involving oro-facial asymmetries in nonhuman primates have largely demonstrated a right hemispheric dominance for communicative signals and conveyance of emotional information. A recent study on chimpanzee reported the first evidence of significant left-hemispheric dominance when using attention-getting sounds and rightward bias for species-typical vocalizations (Losin, Russell, Freeman, Meguerditchian, Hopkins & Fitch, 2008). The current study sought to extend the findings from Losin et al. (2008) with additional oro-facial assessment in a new colony of chimpanzees. When combining the two populations, the results indicated a consistent leftward bias for attention-getting sounds and a right lateralization for species-typical vocalizations. Collectively, the results suggest that both voluntary-controlled oro-facial and gestural communication might share the same left-hemispheric specialization and might have coevolved into a single integrated system present in a common hominid ancestor.

Gender differences in aging: cognition, emotions, and neuroimaging studies

Gender and aging moderate brain-behavior relationships. Advances in neuroscience enable integration of neurobehavioral, neuroanatomic, and neurophysiology measures. Here we present neurobehavioral studies thai examine cognitive and emotion processing in healthy men and women and highlight the effects of sex differences and aqinq. Neuroanatomic studies with maqnetic resonance imaging (MRI) indicate that the progressive decrease in brain volume affects froniotemporal brain regions in men more than in Vi/omen, Functional imaging methods suggest sex differences in rate of blood flow, pattern of glucose metabolism, and receptor activity. The role of ovarian hormones is important in elucidating the observed relationships. A life span perspective on gender differences through the integration of available methodologies will advance understanding healthy people and the effects of brain disorders.

First evidence of population-level oro-facial asymmetries during the production of distress calls by macaque (Macaca mulatta) and baboon (Papio anubis) infants

Infant distress calls are vocal communicative signals present in most animals. In nonhuman primates, they correspond to critical vocalizations for caregiving and contribute to the socio-emotional development of the individual. To our knowledge, no systematic study on the development of oro-facial hemispheric specialization in nonhuman primates infants is available. Thus, we proposed to assess to what extend emotional behaviors underlying distress calls in macaques and in baboons younger than 1 year of age may express lateralization. For the first time, a population-level cerebral lateralization was found for screaming and cooing calls in macaques and for the moaning call in baboons. However, differences in patterns of lateralization were found between the two vocalizations produced by macaques (for cooing, the left-side of the mouth opened widest than the right one and for screaming, a preference toward the right side of the mouth was noticed) as well as a sex effect for cooing. Our findings are discussed within the comparative literature in order to comprehend the ontogenetic and phylogenetic changes of hemispheric specialization for emotions in the primate order.