Facial emotion recognition in Parkinson's disease: A review and new hypotheses

Social Cognition in Parkinson's Disease after Focused Ultrasound Subthalamotomy: A Controlled Study

Social cognition (SC) encompasses a set of cognitive functions that enable individuals to understand and respond appropriately to social interactions. Although focused ultrasound subthalamotomy (FUS-STN) effectively treats Parkinson's disease (PD) clinical motor features, its impact and safety on cognitive-behavioral interactions/interpersonal awareness are unknown. This study investigated the effects of unilateral FUS-STN on facial emotion recognition (FER) and affective and cognitive theory of mind (ToM) in PD patients from a randomized sham-controlled trial (NCT03454425). Subjects performed SC evaluation before and 4 months after the procedure while still under blind assessment conditions. The SC assessment included the Karolinska Directed Emotional Faces task for FER, the Reading the Mind in the Eyes (RME) test for affective ToM, and The Theory of Mind Picture Stories Task (ToM PST) (order, questions, and total score) for cognitive ToM. The active treatment group showed anecdotal-to-moderate evidence of no worsening in SC after FUS-STN. Anecdotal evidence for an improvement was recognized in the SC score changes, from baseline to post-treatment, for the active treatment group compared with sham for the RME, ToM PST order, ToM PST total, FER total, and recognition of fear, disgust, and anger. This study provides the first evidence that unilateral FUS-STN does not impair social cognitive abilities, indicating that it can be considered a safe treatment approach for this domain in PD patients. Furthermore, the results suggest FUS-STN may even lead to some improvement in social cognitive outcomes, which should be considered as a preliminary finding requiring further investigation with larger samples sizes. © 2024 International Parkinson and Movement Disorder Society.

Emotional atypical arousal ratings for unpleasant stimuli in patients with Parkinson's disease

INTRODUCTION

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms, including alteration in emotional processing and recognition of emotions. We explored the effects of PD on the emotional behavioral ratings using a battery of affective visual stimuli selected from the International Affective Picture System (IAPS).

METHODS

Twenty-two patients diagnosed with idiopathic PD and 22 healthy controls (HC), matched by age, gender, and education, were enrolled in the study. Following a clinical assessment, each participant was asked to evaluate the arousal and valence of affective visual stimuli, and response time was recorded. Disease-specific measures including the MDS Unified Parkinson's Disease Rating Scale (MDS UPDRS) and the Non-Motor Symptom Scale (NMSS) were also collected.

RESULTS

PD patients exhibited higher arousal responses compared to HC for negative/unpleasant pictures (scoring 7.32 ± 0.88 vs 5.43 ± 2.06, p < 0.001). The arousal response to negative/unpleasant pictures was correlated with measures of non-motor burden in PD (MDS UPDRS I and NMSS, rho = 0.480 and p = 0.023, rho = 0.533 and p = 0.010, respectively).

CONCLUSION

Impaired emotional processing characterizes PD patients with mild disease and is related to the non-motor symptom burden. Given the importance of emotional processing for the development and maintenance of close interpersonal relationship and for coping with specific medical situations, it is crucial to direct PD patients towards therapeutic interventions focused on the recognition and processing of emotions.

The Emotion Authenticity Recognition (EAR) test: normative data of an innovative test using dynamic emotional stimuli to evaluate the ability to recognize the authenticity of emotions expressed by faces

Despite research has massively focused on how emotions conveyed by faces are perceived, the perception of emotions' authenticity is a topic that has been surprisingly overlooked. Here, we present the Emotion Authenticity Recognition (EAR) test, a test specifically developed using dynamic stimuli depicting authentic and posed emotions to evaluate the ability of individuals to correctly identify an emotion (emotion recognition index, ER Index) and classify its authenticity (authenticity recognition index (EA Index). The EAR test has been validated on 522 healthy participants and normative values are provided. Correlations with demographic characteristics, empathy and general cognitive status have been obtained revealing that both indices are negatively correlated with age, and positively with education, cognitive status and different facets of empathy. The EAR test offers a new ecological test to assess the ability to detect emotion authenticity that allow to explore the eventual social cognitive deficit even in patients otherwise cognitively intact.

Phenomena of hypo- and hyperconnectivity in basal ganglia-thalamo-cortical circuits linked to major depression: a 7T fMRI study

Major depressive disorder (MDD) typically manifests itself in depressed affect, anhedonia, low energy, and additional symptoms. Despite its high global prevalence, its pathophysiology still gives rise to questions. Current research places alterations in functional connectivity among MDD's most promising biomarkers. However, given the heterogeneity of previous findings, the use of higher-resolution imaging techniques, like ultra-high field (UHF) fMRI (≥7 Tesla, 7T), may offer greater specificity in delineating fundamental impairments. In this study, 7T UHF fMRI scans were conducted on 31 MDD patients and 27 age-gender matched healthy controls to exploratorily contrast cerebral resting-state functional connectivity patterns between both groups. The CONN toolbox was used to generate functional network connectivity (FNC) analysis based on the region of interest (ROI)-to-ROI correlations in order to enable the identification of clusters of significantly different connections. Correction for multiple comparisons was implemented at the cluster level using a false discovery rate (FDR). The analysis revealed three significant clusters differentiating MDD patients and healthy controls. In Clusters 1 and 2, MDD patients exhibited between-network hypoconnectivity in basal ganglia-cortical pathways as well as hyperconnectivity in thalamo-cortical pathways, including several individual ROI-to-ROI connections. In Cluster 3, they showed increased occipital interhemispheric within-network connectivity. These findings suggest that alterations in basal ganglia-thalamo-cortical circuits play a substantial role in the pathophysiology of MDD. Furthermore, they indicate potential MDD-related deficits relating to a combination of perception (vision, audition, and somatosensation) as well as more complex functions, especially social-emotional processing, modulation, and regulation. It is anticipated that these findings might further inform more accurate clinical procedures for addressing MDD.

Recognition of emotional face expressions in patients with restless legs syndrome

OBJECTIVE

Restless legs syndrome (RLS) is one of the commonest neurologic diseases. Along with sensory and motor symptoms, cognitive impairment and psychiatric features can be seen with RLS. The present study, was planned to look for evidence of cognitive impairment by evaluating facial emotion recognition (FER) in patients with RLS.

METHODS

In this study, 80 patients with RLS and 50 healthy controls (HCs) were included. Demographic data were recorded. All patients with RLS and HCs were tested with Beck anxiety inventory (BAI), Beck depression inventory (BDI) and with Ekman's test for recognition of facial emotions.

RESULTS

Sixty-three of the patients with RLS and 37 of the HCs were female. The mean age of the patients was 45.41 ± 8.24, and the mean age of HCs was 43.12 ± 10.35. The patients and HCs were similar regarding sex, age, educational status, and marital status. Patients with RLS had FER difficulties comparing HCs. There was a negative correlation between Ekman's test scores and BDI (r = -0.311, p < 0.001) and BAI scores (r = -0.379, p < 0.001).

CONCLUSION

FER is an invaluable research topic regarding cognitive function in RLS, which may help us develop different perspectives in terms of revealing the pathophysiology and is very important for the well-being of the patients' social interactions.

Facial emotion recognition and judgment of affective scenes in Parkinson's disease

Emotional dysfunctions in Parkinson's disease (PD) remain a controversial issue. While previous investigations showed compromised recognition of expressive faces in PD, no studies evaluated potential deficits in recognizing the emotional valence of affective scenes. This study aimed to investigate both facial emotion recognition performance and the ability to judge affective scenes in PD patients. Forty PD patients (mean age ± SD: 64.50 ± 8.19 years; 27 men) and forty healthy subjects (64.95 ± 8.25 years; 27 men) were included. Exclusion criteria were previous psychiatric disorders, previous Deep Brain Stimulation, and cognitive impairment. Participants were evaluated through the Ekman 60-Faces test and the International Affective Picture System. The accuracy in recognizing the emotional valence of facial expressions and affective scenes was compared between groups using linear mixed models. Pearson's correlation was performed to test the association between accuracy measures. The groups did not differ in sex, age, education, and Mini-Mental State Examination scores. Patients showed a lower recognition accuracy of facial expressions (68.54 % ± 15.83 %) than healthy participants (78.67 % ± 12.04 %; p < 0.001). Specifically, the PD group was characterized by lower recognition of faces expressing fear, sadness, and anger than the control group (all p < 0.020). No difference was detected for faces expressing disgust, surprise, and happiness (all p ≥ 0.25). Furthermore, patients showed lower accuracy in recognizing the emotional valence of affective scenes (66.75 % ± 14.59 %) than healthy subjects (74.83 % ± 12.65 %; p = 0.010). Pearson's correlations indicated that higher accuracy in recognizing the emotional facial expressions was associated with higher accuracy in classifying the valence of affective scenes in patients (r = 0.57, p < 0.001) and control participants (r = 0.57, p < 0.001). Our study suggested maladaptive affective processing in PD, leading patients to misinterpret both facial expressions and the emotional valence of complex evocative scenes.

Modulation of response times in early-stage Parkinson's disease during emotional processing of embodied and non-embodied stimuli

Valence (positive and negative) and content (embodied vs non-embodied) characteristics of visual stimuli have been shown to influence motor readiness, as tested with response time paradigms. Both embodiment and emotional processing are affected in Parkinson's disease (PD) due to basal ganglia dysfunction. Here we aimed to investigate, using a two-choice response time paradigm, motor readiness when processing embodied (emotional body language [EBL] and emotional facial expressions [FACS]) vs non-embodied (emotional scenes [IAPS]) stimuli with neutral, happy, and fearful content. We enrolled twenty-five patients with early-stage PD and twenty-five age matched healthy participants. Motor response during emotional processing was assessed by measuring response times (RTs) in a home-based, forced two-choice discrimination task where participants were asked to discriminate the emotional stimulus from the neutral one. Rating of valence and arousal was also performed. A clinical and neuropsychological evaluation was performed on PD patients. Results showed that RTs for PD patients were longer for all conditions compared to HC and that RTs were generally longer in both groups for EBL compared to FACS and IAPS, with the sole exception retrieved for PD, where in discriminating fearful stimuli, RTs for EBL were longer compared to FACS but not to IAPS. Furthermore, in PD only, when discriminating fearful respect to neutral stimuli, RTs were shorter when discriminating FACS compared to IAPS. This study shows that PD patients were faster in discriminating fearful embodied stimuli, allowing us to speculate on mechanisms involving an alternative, compensatory, emotional motor pathway for PD patients undergoing fear processing.

Impaired facial emotion recognition in relation to social behaviours in de novo Parkinson's disease

Facial emotion recognition (FER) is a crucial component of social cognition and is essential in social-interpersonal behaviour regulation. Although FER impairment is well-established in advanced PD, data about FER at the time of diagnosis and its relationship with social behavioural problems in daily life are lacking. The aim was to examine FER at the time of PD diagnosis compared to a matched healthy control (HC) group and to associate FER with indices of social behavioural problems. In total, 142 de novo, treatment-naïve PD patients and 142 HC were included. FER was assessed by the Ekman 60 faces test (EFT). Behavioural problems in PD patients were assessed using the Dysexecutive Questionnaire (DEX-self and DEX-proxy) and the Apathy Evaluation Scale (AES-self). PD patients had significantly lower EFT-total scores (p = .001) compared to HC, with worse recognition of Disgust (p = .001) and Sadness (p = .016). Correlational analyses yielded significant correlations between AES-self and both EFT-total (rs = .28) and Fear (rs = .22). Significant negative correlations were found between DEX-proxy and both EFT-total (rs = -.28) and Anger (rs = -.26). Analyses of DEX-subscales showed that proxy ratings were significantly higher than patient-ratings for the Social Conventions subscale (p = .047). This DEX-proxy subscale had the strongest correlation with EFT-total (rs = -.29). Results show that de novo PD patients already show impaired FER compared to HC. In addition, lower FER is linked to self-reported apathy and proxy-reported social-behavioural problems, especially concerning social conventions. These findings validate the importance of the inclusion of social cognition measures in the neuropsychological assessment even in early PD.

Impairments of Sociocognitive Functions in Individuals with Behavioral Addictions: A Review Article

Since little is known about the exact pattern of social cognitive impairments related to behavioral addictions, the aim of the PRISMA-oriented review was to (i) provide an overview of relevant empirical publications, and to (ii) to elucidate which specific aspects of social cognition (i.e., emotion recognition, empathy, and theory of mind (ToM)) are impaired in different types of behavioral addictions. Behavioral addictions have been associated with cognitive deficits which may contribute to impaired social cognitive functioning. More recently, this domain has been investigated in patients with behavioral addictions as impaired social cognition detrimentally affects daily functioning and thus forms a relevant target for treatment. A systematic search in the PubMed and Web of Science databases was performed focusing on social cognitive functions in behavioral addictions. Studies focusing on the same social cognitive component were grouped together, this was done based on the used assessment measures. In total, 18 studies met the specified inclusion criteria. Five studies focusing on emotion recognition concluded that individuals with behavioral addictions show impairments in this domain. As for the 13 studies focusing on empathy and/or ToM, most of them found deficits linked to different types of behavioral addictions. Only two studies, one of which was investigating a distinct population (multiplayer online role-playing gamers) did not link empathy to behavioral addictions. The results show that the majority of studies focusing on social cognition and behavioral addictions found some deficits. Additional research focusing on this topic is urgently needed in behavioral addictions, addressing several methodological issues.

Tango and physiotherapy interventions in Parkinson's disease: a pilot study on efficacy outcomes on motor and cognitive skills

Pharmacological treatments in Parkinson's disease (PD), albeit effective in alleviating many motor symptoms, have limited effects in non-motor signatures as cognitive impairment, as well as in other aspects included postural instability. Consequently, complementary interventions are nowadays a prerogative of clinical practice managing PD symptomatology. In this pilot longitudinal study, we recruited twenty-four PD patients participating in one of two interventions: adapted Argentine Tango or group-based physiotherapy. Participants underwent a motor and neuropsychological evaluation before and after four months of activities, carried out twice a week. We found a general stabilization of motor and cognitive abilities, with significant improvements in several motor skills, mainly pertaining to static and dynamic balance, similarly in both groups. At cognitive level, we measured a significant improvement in both groups in the Action Naming task. Interestingly, only PD patients in the Tango group improved their performance in the test measuring facial emotion recognition. These findings highlight the crucial role that physical activities have in the stabilization and slowdown of disease's progression in PD. They further highlight the beneficial effects of a group-based physical intervention, which, especially in the case of Tango, could lead to behavioral ameliorations in domains other than the motor, such as emotion recognition.

Perception of emotionally incongruent cues: evidence for overreliance on body vs. face expressions in Parkinson's disease

Individuals with Parkinson's disease (PD) may exhibit impaired emotion perception. However, research demonstrating this decline has been based almost entirely on the recognition of isolated emotional cues. In real life, emotional cues such as expressive faces are typically encountered alongside expressive bodies. The current study investigated emotion perception in individuals with PD (n = 37) using emotionally incongruent composite displays of facial and body expressions, as well as isolated face and body expressions, and congruent composite displays as a baseline. In addition to a group of healthy controls (HC) (n = 50), we also included control individuals with schizophrenia (SZ) (n = 30), who display, as in PD, similar motor symptomology and decreased emotion perception abilities. The results show that individuals with PD showed an increased tendency to categorize incongruent face-body combinations in line with the body emotion, whereas those with HC showed a tendency to classify them in line with the facial emotion. No consistent pattern for prioritizing the face or body was found in individuals with SZ. These results were not explained by the emotional recognition of the isolated cues, cognitive status, depression, or motor symptoms of individuals with PD and SZ. As real-life expressions may include inconsistent cues in the body and face, these findings may have implications for the way individuals with PD and SZ interpret the emotions of others.

Daily Phonatory Activity of Individuals With Parkinson's Disease

PURPOSE

This study evaluated the amount of phonatory activity of Persons with Parkinson disease (PwPD) compared to adults without Parkinson's disease measured over 3 days. The relationship between the amount of phonatory activity and Voice Handicap Index (VHI) total score was assessed as were differences in voicing activity across 3 days of data collection.

METHODS

Fifteen PwPD receiving dopaminergic medication and fifteen age and sex matched adults without Parkinson's disease completed the VHI and then wore a VocaLog vocal monitor (VM) for 3 consecutive days. From the VM data, the number of 1-second windows with dB sound pressure level > 0 were summed as a measure of phonatory activity (PA) and reported relative to the time the VM was worn (%PA).

RESULTS

The percentage of time the VM was worn did not differ between groups or across days. The PwPD had statistically significantly fewer minutes of PA per day than controls (F = 21.782, P < 0.001) by 54 minutes on average. The %PA also differed significantly (F = 31.825, P < 0.001) with a mean of 11.1% for PwPD and 18.6% for controls. Neither PA nor %PA differed across the 3 days of vocal monitoring. VHI total score was significantly correlated with PA (r = -0.436, P = 0.016) and %PA (r = -0.534, P = 0.002) for all participants.

CONCLUSIONS

The results indicate that PwPD engaged in less verbal communication in their daily environment compared to adults without Parkinson's disease. The findings support reports in the literature indicating that PwPD often have reduced communication participation. Measures such as %PA could serve as a quantifiable metric in future studies assessing communication changes in PwPD as a function of disease progression or therapeutic interventions.

Auto Diagnosis of Parkinson's Disease Via a Deep Learning Model Based on Mixed Emotional Facial Expressions

Parkinson's disease (PD) is a common degenerative disease of the nervous system in the elderly. The early diagnosis of PD is very important for potential patients to receive prompt treatment and avoid the aggravation of the disease. Recent studies have found that PD patients always suffer from emotional expression disorder, thus forming the characteristics of "masked faces". Based on this, we thus propose an auto PD diagnosis method based on mixed emotional facial expressions in the paper. Specifically, the proposed method is cast into four steps: Firstly, we synthesize virtual face images containing six basic expressions (i.e., anger, disgust, fear, happiness, sadness, and surprise) via generative adversarial learning, in order to approximate the premorbid expressions of PD patients; Secondly, we design an effective screening scheme to assess the quality of the above synthesized facial expression images and then shortlist the high-quality ones; Thirdly, we train a deep feature extractor accompanied with a facial expression classifier based on the mixture of the original facial expression images of the PD patients, the high-quality synthesized facial expression images of PD patients, and the normal facial expression images from other public face datasets; Finally, with the well-trained deep feature extractor, we thus adopt it to extract the latent expression features for six facial expression images of a potential PD patient to conduct PD/non-PD prediction. To show real-world impacts, we also collected a new facial expression dataset of PD patients in collaboration with a hospital. Extensive experiments are conducted to validate the effectiveness of the proposed method for PD diagnosis and facial expression recognition.

Neurocognitive Impairment and Social Cognition in Parkinson's Disease Patients

In addition to motor symptoms, neurocognitive impairment (NCI) affects patients with prodromal Parkinson's disease (PD). NCI in PD ranges from subjective cognitive complaints to dementia. The purpose of this review is to present the available evidence of NCI in PD and highlight the heterogeneity of NCI phenotypes as well as the range of factors that contribute to NCI onset and progression. A review of publications related to NCI in PD up to March 2023 was performed using PubMed/Medline. There is an interconnection between the neurocognitive and motor symptoms of the disease, suggesting a common underlying pathophysiology as well as an interconnection between NCI and non-motor symptoms, such as mood disorders, which may contribute to confounding NCI. Motor and non-motor symptom evaluation could be used prognostically for NCI onset and progression in combination with imaging, laboratory, and genetic data. Additionally, the implications of NCI on the social cognition of afflicted patients warrant its prompt management. The etiology of NCI onset and its progression in PD is multifactorial and its effects are equally grave as the motor effects. This review highlights the importance of the prompt identification of subjective cognitive complaints in PD patients and NCI management.

Facial expressions and identities recognition in Parkinson disease

Parkinson's Disease (PD) is associated with motor and non-motor symptoms. Among the latter are deficits in matching, identification, and recognition of emotional facial expressions. On one hand, this deficit has been attributed to a dysfunction in emotion processing. Another explanation (which does not exclude the former) links this deficit with reduced facial expressiveness in these patients, which prevents them from properly understanding or embodying emotions. To disentangle the specific contribution of emotion comprehension and that of facial expression processing in PD's observed deficit with emotions we performed two experiments on non-emotional facial expressions. In Experiment 1, a group of PD patients and a group of Healthy Controls (HC) underwent a task of non-emotional expression recognition in faces of different identity and a task of identity recognition in faces with different expression. No differences were observed between the two groups in accuracies. In Experiment 2, PD patients and Healthy Controls underwent a task where they had to recognize the identity of faces encoded through a non-emotional facial expression, through a rigid head movement, or as neutral. Again, no group differences were observed. In none of the two experiments hypomimia scores had a specific effect on expression processing. We conclude that in PD patients the observed impairment with emotional expressions is likely due to a specific deficit for emotions to a greater extent than for facial expressivity processing.

The impact of deep brain stimulation of the subthalamic nucleus on facial emotion recognition in patients with Parkinson's disease

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is successful in patients with advanced Parkinson's disease (PD) but may worsen cognitive outcome, including facial emotion recognition (FER). Data-analyses on 59 consecutive PD patients with complete pre- and postoperative assessments, using a sensitive FER test, showed no changes in FER 1 year after STN-DBS surgery, both after group and individual analyses. These findings do however not exclude the impact of FER in and on itself on the outcome after STN-DBS.

Zygomaticus activation through facial neuromuscular electrical stimulation (fNMES) induces happiness perception in ambiguous facial expressions and affects neural correlates of face processing

The role of facial feedback in facial emotion recognition remains controversial, partly due to limitations of the existing methods to manipulate the activation of facial muscles, such as voluntary posing of facial expressions or holding a pen in the mouth. These procedures are indeed limited in their control over which muscles are (de)activated when and to what degree. To overcome these limitations and investigate in a more controlled way if facial emotion recognition is modulated by one's facial muscle activity, we used computer-controlled facial neuromuscular electrical stimulation (fNMES). In a pre-registered EEG experiment, ambiguous facial expressions were categorised as happy or sad by 47 participants. In half of the trials, weak smiling was induced through fNMES delivered to the bilateral Zygomaticus Major muscle for 500 ms. The likelihood of categorising ambiguous facial expressions as happy was significantly increased with fNMES, as shown with frequentist and Bayesian linear mixed models. Further, fNMES resulted in a reduction of P1, N170 and LPP amplitudes. These findings suggest that fNMES-induced facial feedback can bias facial emotion recognition and modulate the neural correlates of face processing. We conclude that fNMES has potential as a tool for studying the effects of facial feedback.

Facial emotion recognition in individuals with mild cognitive impairment: An exploratory study

Understanding facial emotions is fundamental to interact in social environments and modify behavior accordingly. Neurodegenerative processes can progressively transform affective responses and affect social competence. This exploratory study examined the neurocognitive correlates of face recognition, in individuals with two mild cognitive impairment (MCI) etiologies (prodromal to dementia - MCI, or consequent to Parkinson's disease - PD-MCI). Performance on the identification and memorization of neutral and emotional facial expressions was assessed in 31 individuals with MCI, 26 with PD-MCI, and 30 healthy controls (HC). Individuals with MCI exhibited selective impairment in recognizing faces expressing fear, along with difficulties in remembering both neutral and emotional faces. Conversely, individuals with PD-MCI showed no differences compared with the HC in either emotion recognition or memory. In MCI, no significant association emerged between the memory for facial expressions and cognitive difficulties. In PD-MCI, regression analyses showed significant associations with higher-level cognitive functions in the emotional memory task, suggesting the presence of compensatory mechanisms. In a subset of participants, voxel-based morphometry revealed that the performance on emotional tasks correlated with regional changes in gray matter volume. The performance in the matching of negative expressions was predicted by volumetric changes in brain areas engaged in face and emotional processing, in particular increased volume in thalamic nuclei and atrophy in the right parietal cortex. Future studies should leverage on neuroimaging data to determine whether differences in emotional recognition are mediated by pathology-specific atrophic patterns.

Social Cognition and Mild Cognitive Impairment in Mid-Stage Parkinson's Disease

Mild cognitive impairment (MCI) is a relevant non-motor feature in Parkinson's disease (PD). Social cognition (SC) is a cognitive domain that refers to the ability to decode others' intentions and to guide behavior in social contexts. We aimed to compare SC performance in mid-stage PD patients compared to a healthy population and according to their cognitive state. Fifty-two PD patients were classified as being cognitively normal (PD-CN) or having mild cognitive impairment (PD-MCI) following the Movement Disorder Society (MDS) Level II criteria. SC assessment included facial emotion recognition (FER), affective and cognitive theory of mind (ToM), and self-monitoring (RSMS test). Twenty-seven age-matched healthy controls (HC) were enrolled. PD-MCI patients scored worse than HC on affective and cognitive ToM task scores. Only cognitive ToM scores were significantly lower when compared with the PD-MCI and PD-CN groups. We found no differences in FER or self-monitoring performance. There were significant correlations between cognitive ToM and executive functions, memory, language, and attention, whereas FER and affective ToM correlated with memory. Our findings indicates that SC is normal in cognitively unimpaired and non-depressed mid-stage PD patients, whereas a decline in affective and cognitive ToM is linked to the presence of MCI.

The Story behind the Mask: A Narrative Review on Hypomimia in Parkinson's Disease

Facial movements are crucial for social and emotional interaction and well-being. Reduced facial expressions (i.e., hypomimia) is a common feature in patients with Parkinson's disease (PD) and previous studies linked this manifestation to both motor symptoms of the disease and altered emotion recognition and processing. Nevertheless, research on facial motor impairment in PD has been rather scarce and only a limited number of clinical evaluation tools are available, often suffering from poor validation processes and high inter- and intra-rater variability. In recent years, the availability of technology-enhanced quantification methods of facial movements, such as automated video analysis and machine learning application, led to increasing interest in studying hypomimia in PD. In this narrative review, we summarize the current knowledge on pathophysiological hypotheses at the basis of hypomimia in PD, with particular focus on the association between reduced facial expressions and emotional processing and analyze the current evaluation tools and management strategies for this symptom, as well as future research perspectives.

Facial emotion recognition deficits are associated with hypomimia and related brain correlates in Parkinson's disease

Hypomimia is a frequent manifestation in Parkinson's disease (PD) that can affect interpersonal relationships and quality of life. Recent studies have suggested that hypomimia is not only related to motor dysfunction but also to impairment in emotional processing networks. Therefore, we hypothesized that the severity of hypomimia could be associated with performance on a task aimed at assessing facial emotion recognition. In this study, we explored the association between hypomimia, recognition of facial expressions of basic emotions using the Ekman 60 Faces Test (EF), and brain correlates of both hypomimia and performance on the EF. A total of 94 subjects underwent clinical assessments (neurological and neuropsychological examinations), and 56 of them participated in the neuroimaging study. We found significant correlation between hypomimia, EF Disgust (r = -0.242, p = 0.022) and EF Happiness (r = -0.264, p = 0.012); an independent reduction in Cortical Thickness (Cth) in the postcentral gyrus, insula, middle and superior temporal gyri, supramarginal gyrus, banks of the superior temporal sulcus, bilateral fusiform gyri, entorhinal cortex, parahippocampal gyrus, inferior and superior parietal cortex, and right cuneus and precuneus; and multiple correlations between negative emotions such as EF Disgust or EF Anger and a reduced Cth in fronto-temporo-parietal regions. In conclusion, these results suggest that the association between hypomimia and emotion recognition deficits in individuals with PD might be mediated by shared circuits, supporting the concept that hypomimia is not only the result of the dysfunction of motor circuits, but also of higher cognitive functions.

Humanoid facial expressions as a tool to study human behaviour

Besides action vitality forms, facial expressions represent another fundamental social cue which enables to infer the affective state of others. In the present study, we proposed the iCub robot as an interactive and controllable agent to investigate whether and how different facial expressions, associated to different action vitality forms, could modulate the motor behaviour of participants. To this purpose, we carried out a kinematic experiment in which 18 healthy participants observed video-clips of the iCub robot performing a rude or gentle request with a happy or angry facial expression. After this request, they were asked to grasp an object and pass it towards the iCub robot. Results showed that the iCub facial expressions significantly modulated participants motor response. Particularly, the observation of a happy facial expression, associated to a rude action, decreased specific kinematic parameters such as velocity, acceleration and maximum height of movement. In contrast, the observation of an angry facial expression, associated to a gentle action, increased the same kinematic parameters. Moreover, a behavioural study corroborated these findings, showing that the perception of the same action vitality form was modified when associated to a positive or negative facial expression.

Emotion Recognition in Multiple System Atrophy: An Exploratory Eye-Tracking Study

OBJECTIVE

Emotional processing is a core feature of social interactions and has been well studied in patients with idiopathic Parkinson's disease (PD), albeit with contradictory.

RESULTS

. However, these studies excluded patients with atypical parkinsonism, such as multiple system atrophy (MSA). The objective of this exploratory study was to provide better insights into emotion processing in patients with MSA using eye tracking data.

METHODS

We included 21 MSA patients, 15 PD patients and 19 matched controls in this study. Participants performed a dynamic and a static emotion recognition task, and gaze fixations were analyzed in different areas of interest. Participants underwent neuropsychological testing and assessment of depression and alexithymia.

RESULTS

MSA patients were less accurate in recognizing anger than controls (p = 0.02) and had overall fewer fixations than controls (p = 0.001). In the static task, MSA patients had fewer fixations (p < 0.001) and a longer time to first fixation (p = 0.026) on the eye region. Furthermore, MSA patients had a longer fixation duration overall than PD patients (p = 0.004) and longer fixations on the nose than controls (p = 0.005). Alexithymia scores were higher in MSA patients compared to controls (p = 0.038).

CONCLUSION

This study demonstrated impaired recognition of anger in MSA patients compared to HCs. Fewer and later fixations on the eyes along with a center bias suggest avoidance of eye contact, which may be a characteristic gaze behavior in MSA patients.

Facial emotion expressivity in patients with Parkinson's and Alzheimer's disease

Parkinson's disease (PD) and Alzheimer's disease (AD) are neurodegenerative disorders with some overlapping clinical features. Hypomimia (reduced facial expressivity) is a prominent sign of PD and it is also present in AD. However, no study has experimentally assessed hypomimia in AD and compared facial expressivity between PD and AD patients. We compared facial emotion expressivity in patients with PD, AD, and healthy controls (HCs). Twenty-four PD patients, 24 AD patients and 24 HCs were videotaped during neutral facial expressions and while posing six facial emotions (anger, surprise, disgust, fear, happiness, and sadness). Fifteen raters were asked to evaluate the videos using MDS-UPDRS-III (item 3.2) and to identify the corresponding emotion from a seven-forced-choice response format. We measured the percentage of accuracy, the reaction time (RT), and the confidence level (CL) in the perceived accuracy of the raters' responses. We found the highest MDS-UPDRS 3.2 scores in PD, and higher in AD than HCs. When evaluating the posed expression captures, raters identified a lower percentage of correct answers in the PD and AD groups than HCs. There was no difference in raters' response accuracy between the PD and AD. No difference was observed in RT and CL data between groups. Hypomimia in patients correlated positively with the global MDS-UPDRS-III and negatively with Mini Mental State Examination scores. PD and AD patients have a similar pattern of reduced facial emotion expressivity compared to controls. These findings hold potential pathophysiological and clinical implications.

The inside out model of emotion recognition: how the shape of one's internal emotional landscape influences the recognition of others' emotions

Some people are exceptional at reading emotional expressions, while others struggle. Here we ask whether the way we experience emotion "on the inside" influences the way we expect emotions to be expressed in the "outside world" and subsequently our ability to read others' emotional expressions. Across multiple experiments, incorporating discovery and replication samples, we develop EmoMap (N = 20; N = 271) and ExpressionMap (N = 98; replication N = 193) to map adults' experiences of emotions and visual representations of others' emotions. Some individuals have modular maps, wherein emotional experiences and visual representations are consistent and distinct-anger looks and feels different from happiness, which looks and feels different from sadness. In contrast, others have experiences and representations that are variable and overlapping-anger, happiness, and sadness look and feel similar and are easily confused for one another. Here we illustrate an association between these maps: those with consistent and distinct experiences of emotion also have consistent and distinct visual representations of emotion. Finally (N = 193), we construct the Inside Out Model of Emotion Recognition, which explains 60.8% of the variance in emotion recognition and illuminates multiple pathways to emotion recognition difficulties. These findings have important implications for understanding the emotion recognition difficulties documented in numerous clinical populations.

Can the Ability to Recognize Facial Emotions in Individuals With Neurodegenerative Disease be Improved? A Systematic Review and Meta-analysis

BACKGROUND

Facial emotion recognition (FER) is commonly impaired in individuals with neurodegenerative disease (NDD). This impairment has been linked to an increase in behavioral disorders and caregiver burden.

OBJECTIVE

To identify interventions targeting the improvement of FER ability in individuals with NDD and investigate the magnitude of the efficacy of the interventions. We also wanted to explore the duration of the effects of the intervention and their possible impacts on behavioral and psychological symptoms of dementia and caregiver burden.

METHOD

We included 15 studies with 604 individuals who had been diagnosed with NDD. The identified interventions were categorized into three types of approach (cognitive, neurostimulation, and pharmacological) as well as a combined approach (neurostimulation with pharmacological).

RESULTS

The three types of approaches pooled together had a significant large effect size for FER ability improvement (standard mean difference: 1.21, 95% CI = 0.11, 2.31, z = 2.15, P = 0.03). The improvement lasted post intervention, in tandem with a decrease in behavioral disorders and caregiver burden.

CONCLUSION

A combination of different approaches for FER ability improvement may be beneficial for individuals with NDD and their caregivers.

Emotion in action: When emotions meet motor circuits

The brain is a remarkably complex organ responsible for a wide range of functions, including the modulation of emotional states and movement. Neuronal circuits are believed to play a crucial role in integrating sensory, cognitive, and emotional information to ultimately guide motor behavior. Over the years, numerous studies employing diverse techniques such as electrophysiology, imaging, and optogenetics have revealed a complex network of neural circuits involved in the regulation of emotional or motor processes. Emotions can exert a substantial influence on motor performance, encompassing both everyday activities and pathological conditions. The aim of this review is to explore how emotional states can shape movements by connecting the neural circuits for emotional processing to motor neural circuits. We first provide a comprehensive overview of the impact of different emotional states on motor control in humans and rodents. In line with behavioral studies, we set out to identify emotion-related structures capable of modulating motor output, behaviorally and anatomically. Neuronal circuits involved in emotional processing are extensively connected to the motor system. These circuits can drive emotional behavior, essential for survival, but can also continuously shape ongoing movement. In summary, the investigation of the intricate relationship between emotion and movement offers valuable insights into human behavior, including opportunities to enhance performance, and holds promise for improving mental and physical health. This review integrates findings from multiple scientific approaches, including anatomical tracing, circuit-based dissection, and behavioral studies, conducted in both animal and human subjects. By incorporating these different methodologies, we aim to present a comprehensive overview of the current understanding of the emotional modulation of movement in both physiological and pathological conditions.

The importance of social behavior in nonhuman primate studies of aging: A mini-review

Social behavior plays an important role in supporting both psychological and physical health across the lifespan. People's social lives change as they age, and the nature of these changes differ based on whether people are on healthy aging trajectories or are experiencing neurodegenerative diseases that cause dementia, such as Alzheimer's disease and Parkinson's disease. Nonhuman primate models of aging have provided a base of knowledge comparing aging trajectories in health and disease, but these studies rarely emphasize social behavior changes as a consequence of the aging process. What data exist hold particular value, as negative effects of disease and aging on social behavior are likely to have disproportionate impacts on quality of life. In this mini review, we examine the literature on nonhuman primate models of aging with a focus on social behavior, in the context of both health and disease. We propose that adopting a greater focus on social behavior outcomes in nonhuman primates will improve our understanding of the intersection of health, aging and sociality in humans.

Longitudinal assessment of social cognition in de novo Parkinson's disease patients and its relationship with dopaminergic innervation

BACKGROUND

Social Cognition (SC) has been scarcely studied in Parkinson's disease (PD), and findings in early disease are controversial. SC encompasses different capacities such as facial emotion recognition (FER); Theory of Mind (ToM), the ability to understand other people's intentions (cognitive-ToM) and emotions (affective-ToM); and self-monitoring, the ability to regulate one's own behavior in social contexts. A relationship between dopaminergic deficit and SC in PD has been suggested.

OBJECTIVES

To prospectively assess, over a two-year period, SC in newly diagnosed drug-naïve, cognitively normal and non-depressed PD patients. Furthermore, we aimed to evaluate the relationship between SC and Fluorodopa (Positron Emission Tomography) Ki uptake, which is a marker of dopaminergic depletion.

METHODS

We compared SC performance between 25 de novo PD patients and 20 healthy controls (HC), and within-patients at baseline and two-year follow-up. The SC assessment included FER, ToM, as well as self-monitoring measures. The relationship between SC and dopaminergic innervation was also assessed in patients.

RESULTS

SC scores did not differ between PD and HC groups at baseline, nor between baseline and follow-up evaluation in PD. A significant positive correlation between self-monitoring and Fluorodopa Ki uptake in the left pallidum in PD patients was found at baseline. At follow-up, ToM (stories) positively correlated with Fluorodopa Ki uptake in the right thalamus and the left putamen.

CONCLUSION

SC appears to be preserved in de novo PD and remains stable in the short-term. Although more evidence is needed, our results support a relationship between dopamine innervation in subcortical regions and SC.

Emotion recognition in EEG signals using deep learning methods: A review

Emotions are a critical aspect of daily life and serve a crucial role in human decision-making, planning, reasoning, and other mental states. As a result, they are considered a significant factor in human interactions. Human emotions can be identified through various sources, such as facial expressions, speech, behavior (gesture/position), or physiological signals. The use of physiological signals can enhance the objectivity and reliability of emotion detection. Compared with peripheral physiological signals, electroencephalogram (EEG) recordings are directly generated by the central nervous system and are closely related to human emotions. EEG signals have the great spatial resolution that facilitates the evaluation of brain functions, making them a popular modality in emotion recognition studies. Emotion recognition using EEG signals presents several challenges, including signal variability due to electrode positioning, individual differences in signal morphology, and lack of a universal standard for EEG signal processing. Moreover, identifying the appropriate features for emotion recognition from EEG data requires further research. Finally, there is a need to develop more robust artificial intelligence (AI) including conventional machine learning (ML) and deep learning (DL) methods to handle the complex and diverse EEG signals associated with emotional states. This paper examines the application of DL techniques in emotion recognition from EEG signals and provides a detailed discussion of relevant articles. The paper explores the significant challenges in emotion recognition using EEG signals, highlights the potential of DL techniques in addressing these challenges, and suggests the scope for future research in emotion recognition using DL techniques. The paper concludes with a summary of its findings.

Social and non-social working memory in neurodegeneration

Although social functioning relies on working memory, whether a social-specific mechanism exists remains unclear. This undermines the characterization of neurodegenerative conditions with both working memory and social deficits. We assessed working memory domain-specificity across behavioral, electrophysiological, and neuroimaging dimensions in 245 participants. A novel working memory task involving social and non-social stimuli with three load levels was assessed across controls and different neurodegenerative conditions with recognized impairments in: working memory and social cognition (behavioral-variant frontotemporal dementia); general cognition (Alzheimer's disease); and unspecific patterns (Parkinson's disease). We also examined resting-state theta oscillations and functional connectivity correlates of working memory domain-specificity. Results in controls and all groups together evidenced increased working memory demands for social stimuli associated with frontocinguloparietal theta oscillations and salience network connectivity. Canonical frontal theta oscillations and executive-default mode network anticorrelation indexed non-social stimuli. Behavioral-variant frontotemporal dementia presented generalized working memory deficits related to posterior theta oscillations, with social stimuli linked to salience network connectivity. In Alzheimer's disease, generalized working memory impairments were related to temporoparietal theta oscillations, with non-social stimuli linked to the executive network. Parkinson's disease showed spared working memory performance and canonical brain correlates. Findings support a social-specific working memory and related disease-selective pathophysiological mechanisms.

The impact of loneliness on quality of life in people with Parkinson's disease: results from the Survey of Health, Ageing and Retirement in Europe

Background

Loneliness is a growing issue for public health in an aging society. However, there is a lack of research on loneliness in people with Parkinson's disease (PwPD).

Methods

We analyzed cross-sectional and longitudinal data from wave 5 (N = 559 PwPD) and 6 (N = 442 PwPD) from the Survey of Health, Ageing and Retirement in Europe (SHARE). Loneliness was assessed using the three-item version of the Revised UCLA Loneliness Scale. Descriptive statistics, group comparisons, multiple linear regressions, and generalized estimating equation analysis were performed to explore loneliness prevalence, its relationship with other factors, and its impact on Quality of Life (QoL) in PwPD.

Results

Depending on the used cut-off, the prevalence of loneliness in PwPD ranged from 24.1 to 53.8%. These prevalences were higher compared to people without PD. Loneliness was mainly linked to decreased functional abilities, weaker grip strength, more symptoms of depression, and country of residence. Loneliness was also associated with current QoL and predicts future QoL in PwPD, highlighting its impact on well-being.

Conclusion

Addressing loneliness could potentially improve QoL for PwPD, making it a modifiable risk factor that clinicians and policy-makers should consider.

Are you angry? Neural basis of impaired facial expression recognition in pre-manifest Huntington's

INTRODUCTION

Early non-motor symptoms in Huntington's disease (HD), including visual perceptual difficulties, can have profound negative impacts on quality of life. In particular, deficits in emotion recognition may contribute to misinterpretation of social cues, and may adversely affect interpersonal relationships, work relationships and/or general well-being. This may be particularly salient during the pre-manifest period, a period prior to the onset of motor symptoms. We sought to evaluate impairments in emotion recognition in gene-positive individuals who did not meet criterial for a diagnosis of HD; we also sought to determine associations between emotion recognition processing and altered cortico-striatal circuitry.

METHODS

We used a standardized battery to evaluate performance on a facial expression recognition task in a cohort of motor pre-manifest HD (Pre-HD) individuals (N = 21). Functional MRI (fMRI) was then used to assess the face processing network in a subset (N = 15).

RESULTS

We found significantly decreased response accuracy to certain facial expressions, particularly of negative emotions (p < 0.001) in Pre-HDs. When Pre-HDs viewed faces with different emotions, activation within the Superior Temporal Sulcus (fSTS) was reduced compared to controls; in contrast, the level of evoked response within other face-selective cortical regions was comparable.

CONCLUSION

Early deficits in emotion recognition in Pre-HD appear to be associated with alterations in the fSTS response, a distinctly different pathway from that involved in face perception and provide support for early cognitive and behavioral interventions.

A scoping review of neurodegenerative manifestations in explainable digital phenotyping

Neurologists nowadays no longer view neurodegenerative diseases, like Parkinson's and Alzheimer's disease, as single entities, but rather as a spectrum of multifaceted symptoms with heterogeneous progression courses and treatment responses. The definition of the naturalistic behavioral repertoire of early neurodegenerative manifestations is still elusive, impeding early diagnosis and intervention. Central to this view is the role of artificial intelligence (AI) in reinforcing the depth of phenotypic information, thereby supporting the paradigm shift to precision medicine and personalized healthcare. This suggestion advocates the definition of disease subtypes in a new biomarker-supported nosology framework, yet without empirical consensus on standardization, reliability and interpretability. Although the well-defined neurodegenerative processes, linked to a triad of motor and non-motor preclinical symptoms, are detected by clinical intuition, we undertake an unbiased data-driven approach to identify different patterns of neuropathology distribution based on the naturalistic behavior data inherent to populations in-the-wild. We appraise the role of remote technologies in the definition of digital phenotyping specific to brain-, body- and social-level neurodegenerative subtle symptoms, emphasizing inter- and intra-patient variability powered by deep learning. As such, the present review endeavors to exploit digital technologies and AI to create disease-specific phenotypic explanations, facilitating the understanding of neurodegenerative diseases as "bio-psycho-social" conditions. Not only does this translational effort within explainable digital phenotyping foster the understanding of disease-induced traits, but it also enhances diagnostic and, eventually, treatment personalization.

I spy with my little eye: The detection of changes in emotional faces and the influence of facial feedback in Parkinson disease

BACKGROUND AND PURPOSE

Parkinson disease (PD) is a progressive neurodegenerative disorder that affects the motor system but also involves deficits in emotional processing such as facial emotion recognition. In healthy participants, it has been shown that facial mimicry, the automatic imitation of perceived facial expressions, facilitates the interpretation of the emotional states of our counterpart. In PD patients, recent studies revealed reduced facial mimicry and consequently reduced facial feedback, suggesting that this reduction might contribute to the prominent emotion recognition deficits found in PD.

METHODS

We investigated the influence of facial mimicry on facial emotion recognition. Twenty PD patients and 20 healthy controls (HCs) underwent a classical facial mimicry manipulation (holding a pen with the lips, teeth, or nondominant hand) while performing an emotional change detection task with faces.

RESULTS

As expected, emotion recognition was significantly influenced by facial mimicry manipulation in HCs, further supporting the hypothesis of facial feedback and the related theory of embodied simulation. Importantly, patients with PD, generally and independent from the facial mimicry manipulation, were impaired in their ability to detected emotion changes. Our data further show that PD patients' facial emotional recognition abilities are completely unaffected by mimicry manipulation, suggesting that PD patients cannot profit from an artificial modulation of the already impaired facial feedback.

CONCLUSIONS

These findings suggest that it is not the hypomimia and the absence of facial feedback per se, but a disruption of the facial feedback loop, that leads to the prominent emotion recognition deficit in PD patients.

The FACE test: a new neuropsychological task to assess the recognition of complex mental states from faces

BACKGROUND

Social cognition deficits are reported in several neurodegenerative diseases, including Parkinson's disease (PD). However, the availability of tasks for the clinical assessment is still limited, preventing the full characterization of socio-cognitive dysfunctions in neurological patients. This study aims to present a new task to assess the recognition of complex mental states from faces (FACE test), reporting normative data for the Italian population and an example of its clinical application to 40 PD patients.

METHODS

Two-hundred twenty-nine Italian participants with at least 5 years of education were enrolled. Data were analyzed according to the method of equivalent scores; test-retest reliability and convergent validity were assessed. Two short versions of the FACE test were defined for clinical and research purposes. The prevalence of deficits in the FACE test was computed in the PD sample, as well as correlations with cognitive performance and diagnostic accuracy.

RESULTS

Regression analyses revealed significant effects of demographic variables on FACE performance, with younger and more educated individuals showing higher scores. Twenty-eight percent of PD patients showed borderline/pathological performance, which was correlated with emotion recognition/attribution abilities, and attentive-executive functions. The FACE test was accurate (80%) in distinguishing PD patients with socio-cognitive dysfunctions from both controls and PD patients without emotion recognition/attribution difficulties.

CONCLUSION

The FACE test represents a new tool assessing the ability to recognize complex mental states from facial expressions. Overall, these results support its use in both clinical and research settings, as well as the presence of affective processing deficits in a subsample of PD patients.

Beyond shallow feelings of complex affect: Non-motor correlates of subjective emotional experience in Parkinson's disease

Affective disorders in Parkinson's disease (PD) concern several components of emotion. However, research on subjective feeling in PD is scarce and has produced overall varying results. Therefore, in this study, we aimed to evaluate the subjective emotional experience and its relationship with autonomic symptoms and other non-motor features in PD patients. We used a battery of film excerpts to elicit Amusement, Anger, Disgust, Fear, Sadness, Tenderness, and Neutral State, in 28 PD patients and 17 healthy controls. Self-report scores of emotion category, intensity, and valence were analyzed. In the PD group, we explored the association between emotional self-reported scores and clinical scales assessing autonomic dysregulation, depression, REM sleep behavior disorder, and cognitive impairment. Patient clustering was assessed by considering relevant associations. Tenderness occurrence and intensity of Tenderness and Amusement were reduced in the PD patients. Tenderness occurrence was mainly associated with the overall cognitive status and the prevalence of gastrointestinal symptoms. In contrast, the intensity and valence reported for the experience of Amusement correlated with the prevalence of urinary symptoms. We identified five patient clusters, which differed significantly in their profile of non-motor symptoms and subjective feeling. Our findings further suggest the possible existence of a PD phenotype with more significant changes in subjective emotional experience. We concluded that the subjective experience of complex emotions is impaired in PD. Non-motor feature grouping suggests the existence of disease phenotypes profiled according to specific deficits in subjective emotional experience, with potential clinical implications for the adoption of precision medicine in PD. Further research on larger sample sizes, combining subjective and physiological measures of emotion with additional clinical features, is needed to extend our findings.

Automatic and controlled attentional orienting toward emotional faces in patients with Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative motor disorder that can associate with deficits in cognitive and emotional processing. In particular, PD has been reported to be mainly associated with defects in executive control and orienting attentional systems. The deficit in emotional processing mainly emerged in facial expression recognition. It is possible that the defects in emotional processing in PD may be secondary to other cognitive impairments, such as attentional deficits. This study was designed to systematically investigate the different weight of automatic and controlled attentional orienting mechanisms implied in emotional selective attention in PD. To address our purpose, we assessed drug-naïve PD patients and age-matched healthy controls with two dot-probe tasks that differed for stimuli duration. Automatic and controlled attentions were evaluated with stimuli lasting 100 ms and 500 ms, respectively. Furthermore, we introduced an emotion recognition task to investigate the performance in explicit emotion classification. The stimuli used in both the tasks dot-probe and emotion recognition were expressive faces displaying neutral, disgusted, fearful, and happy expressions.Our results showed that in PD patients, compared with healthy controls, there was 1) an alteration of automatic and controlled attentional orienting toward emotional faces in both the dot-probe tasks (with short and long durations), and 2) no difference in the emotion recognition task. These findings suggest that, from the early stages of the disease, PD can yield specific deficits in implicit emotion processing task (i.e., dot-probe task) despite a normal performance in explicit tasks that demand overt emotion recognition.

Exploring facial expressions and action unit domains for Parkinson detection

BACKGROUND AND OBJECTIVE

Patients suffering from Parkinson's disease (PD) present a reduction in facial movements called hypomimia. In this work, we propose to use machine learning facial expression analysis from face images based on action unit domains to improve PD detection. We propose different domain adaptation techniques to exploit the latest advances in automatic face analysis and face action unit detection.

METHODS

Three different approaches are explored to model facial expressions of PD patients: (i) face analysis using single frame images and also using sequences of images, (ii) transfer learning from face analysis to action units recognition, and (iii) triplet-loss functions to improve the automatic classification between patients and healthy subjects.

RESULTS

Real face images from PD patients show that it is possible to properly model elicited facial expressions using image sequences (neutral, onset-transition, apex, offset-transition, and neutral) with accuracy improvements of up to 5.5% (from 72.9% to 78.4%) with respect to single-image PD detection. We also show that our proposed action unit domain adaptation provides improvements of up to 8.9% (from 78.4% to 87.3%) with respect to face analysis. Finally, we also show that triplet-loss functions provide improvements of up to 3.6% (from 78.8% to 82.4%) with respect to action unit domain adaptation applied upon models created from scratch. The code of the experiments is available at https://github.com/luisf-gomez/Explorer-FE-AU-in-PD.

CONCLUSIONS

Domain adaptation via transfer learning methods seem to be a promising strategy to model hypomimia in PD patients. Considering the good results and also the fact that only up to five images per participant are considered in each sequence, we believe that this work is a step forward in the development of inexpensive computational systems suitable to model and quantify problems of PD patients in their facial expressions.

Role of serotonin in modulation of decision-making in Parkinson's disease

BACKGROUND

Dysfunction of dopaminergic pathways has been considered to play a pivotal role in Parkinson's disease (PD), affecting the processing of emotional and rewarding information, and potentially leading to symptoms of depression or apathy. However, some aspects of motivation in PD might be affected by non-dopaminergic mechanisms.

AIM AND METHOD

The objective of this experimental medicine study was to investigate the contribution of serotonergic modulation via administration of citalopram (20 mg) for 7 days on motivated decision-making in twenty PD patients, measured using several different computerised tasks and clinical questionnaires that probe different aspects of decision-making. Twenty healthy controls were additionally tested without medication to assess any baseline differences between the two groups.

RESULTS

Results indicated that PD patients were overall less motivated than controls on an effort- and reward-based decision-making task. Citalopram increased or decreased willingness to exert effort for reward, depending on whether baseline motivation was high or low, respectively. A task assessing decision-making under risk revealed higher levels of risk aversion for potential losses in PD patients, which neither serotonin nor the patient's regular dopaminergic medication seemed to restore. However, citalopram in PD was associated with more risk-seeking choices for gains, although patients and controls did not differ on this at baseline.

CONCLUSION

The results provide evidence for a role of the serotonergic system in influencing some aspects of motivated decision-making in PD processes.

Social cognition training improves recognition of distinct facial emotions and decreases misattribution errors in healthy individuals

Facial emotion recognition is a key component of social cognition. Impaired facial emotion recognition is tied to poor psychological wellbeing and deficient social functioning. While previous research has demonstrated the potential for social cognition training to improve overall facial emotion recognition, questions remain regarding what aspects of emotion recognition improve. We report results from a randomized controlled trial that evaluates whether computerized social cognition training can improve recognition of distinct facial emotions in healthy participants. This investigation was designed to better understand the therapeutic potential of social cognition training for individuals with neuropsychiatric disorders. Fifty-five healthy adult participants were randomly assigned to an internet-based intervention during which they either completed social cognition training (SCT) or played control computer games (CON) for 10.5 h over 2-3 weeks. Facial emotion recognition was measured with the Penn ER-40, which was conducted before and after training. The following variables were collected and analyzed: facial emotion recognition accuracy for each emotion (i.e., anger, fear, happy, neutral (no emotional expression), and sad), reaction times for each emotion, and response error types (i.e., frequency of an emotion being chosen incorrectly, frequency of an emotion being missed, and frequency of an emotion being confused for another particular emotion). ANOVAs and t-tests were used to elucidate intervention effects both within and between groups. Results showed that the SCT group improved their accuracy for angry and neutral faces. They also improved their reaction times for neutral, fearful, and sad faces. Compared to the CON group, the SCT group had significantly faster reaction times to neutral faces after training. Lastly, the SCT group decreased their tendency to confuse angry faces for no emotional expression and to confuse no emotional expression for sad faces. In contrast, the CON group did not significantly improve their accuracy or reaction times on any emotional expression, and they did not improve their response error types. We conclude that social cognition training can improve recognition of distinct emotions in healthy participants and decrease response error patterns, suggesting it has the potential to improve impaired emotion recognition and social functioning in individuals with facial emotion recognition deficits.

Effects of emotional valence and intensity on cognitive and affective empathy after insula lesions

The insula plays a central role in empathy. However, the complex structure of cognitive (CE) and affective empathy (AE) deficits following insular damage is not fully understood. In the present study, patients with insular lesions (n = 20) and demographically matched healthy controls (n = 24) viewed ecologically valid videos that varied in terms of valence and emotional intensity. The videos showed a person (target) narrating a personal life event. In CE conditions, subjects continuously rated the affective state of the target, while in AE conditions, they continuously rated their own affect. Mean squared error (MSE) assessed deviations between subject and target ratings. Patients differed from controls only in negative, low-intensity AE, rating their own affective state less negative than the target. This deficit was not related to trait empathy, neuropsychological or clinical parameters, or laterality of lesion. Empathic functions may be widely spared after insular damage in a naturalistic, dynamic setting, potentially due to the intact interpretation of social context by residual networks outside the lesion. The particular role of the insula in AE for negative states may evolve specifically in situations that bear higher uncertainty pointing to a threshold role of the insula in online ratings of AE.

Mild cognitive impairment in patients with Parkinson’s disease: An updated mini-review and future outlook

Mild cognitive impairment (MCI) is one of the common non-motor symptoms in patients with Parkinson’s disease (PD). MCI is the transition stage between normal aging and full-blown dementia and is also a powerful predictor of dementia. Although the concept of MCI has been used to describe some of the PD symptoms for many years, there is a lack of consistent diagnostic criteria. Moreover, because of the diverse patterns of the cognitive functions, each cognitive impairment will have a different progression. In this review, we overviewed the diagnostic criteria for PD-MCI, primarily focused on the heterogeneity of PD-MCI patients’ cognitive function, including various types of cognitive functions and their progression rates. A review of this topic is expected to be beneficial for clinical diagnosis, early intervention, and treatment. In addition, we also discussed the unmet needs and future vision in this field.

Social decision-making in Parkinson's disease

INTRODUCTION

Parkinson's Disease (PD) commonly affects cognition and communicative functions, including the ability to perceive socially meaningful cues from nonverbal behavior and spoken language (e.g., a speaker's tone of voice). However, we know little about how people with PD use social information to make decisions in daily interactions (e.g., decisions to trust another person) and whether this ability rests on intact cognitive functions and executive/decision-making abilities in nonsocial domains.

METHOD

Non-demented adults with and without PD were presented utterances that conveyed differences in speaker confidence or politeness based on the way that speakers formulated their statement and their tone of voice. Participants had to use these speech-related cues to make trust-related decisions about interaction partners while playing the Trust Game. Explicit measures of social perception, nonsocial decision-making, and related cognitive abilities were collected.

RESULTS

Individuals with PD displayed significant differences from control participants in social decision-making; for example, they showed greater trust in game partners whose voice sounded confident and who explicitly stated that they would cooperate with the participant. The PD patients displayed relative intact social perception (speaker confidence or politeness ratings) and were unimpaired on a nonsocial decision-making task (the Dice game). No obvious relationship emerged between measures of social perception, social decision-making, or cognitive functioning in the PD sample.

CONCLUSIONS

Results provide evidence of alterations in decision-making restricted to social contexts in PD individuals with relatively preserved cognition with minimal changes in social perception. Researchers and practitioners interested in how PD affects social perception and cognition should include assessments that emulate social interactions, as non-interactive tasks may fail to detect the full impact of the disease on those affected.

Posterior-prefrontal and medial orbitofrontal regions play crucial roles in happiness and sadness recognition

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Brain areas underlying trade-off relations between emotions were identified.

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Damage to the PPF area reduces accuracy of happiness recognition.

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Damage to the PPF increases accuracy of sadness recognition.

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A similar tendency was observed in orbitofrontal regions for sadness recognition.

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Only a deficit in sadness, but not happiness, persisted in the chronic phase.

The core brain regions responsible for basic human emotions are not yet fully understood. We investigated the key areas responsible for emotion recognition of facial expressions of happiness and sadness using data obtained from patients who underwent local brain resection. A total of 44 patients with right cerebral hemispheric brain tumors and 33 healthy volunteers were enrolled and subjected to a facial expression recognition test. Voxel-based lesion-symptom mapping was performed to investigate the relationship between the accuracy of emotion recognition and the resected regions. Consequently, trade-off relationships were discovered: the posterior-prefrontal region was related to a low score of happiness recognition and a high score of sadness recognition (disorder-of-happiness group), whereas the medial orbitofrontal region was related to a low score of sadness recognition and a high score of happiness recognition (disorder-of-sadness group). The emotion recognition score in both the happiness and sadness disorder groups was significantly lower than that in the control group (p = 0.0009 and p = 0.021, respectively). Interestingly, the deficit in happiness recognition was temporary, whereas the deficit in sadness recognition persisted during the chronic phase. Using graph theoretical analysis, we identified structural connectivity between the posterior-prefrontal and medial orbitofrontal regions. When either of these regions was damaged, the tract volume connecting them was significantly reduced (p = 0.013). These results indicate that the posterior-prefrontal and medial orbitofrontal regions may be crucial for maintaining a balance between happiness and sadness recognition in humans. Investigating the clinical impact of certain area resections using lesion studies combined with connectivity analysis is a useful neuroimaging method for understanding neural networks.

Can AI make people happy? The effect of AI-based chatbot on smile and speech in Parkinson's disease

INTRODUCTION

Approaches for objectively measuring facial expressions and speech may enhance clinical and research evaluation in telemedicine, which is widely employed for Parkinson's disease (PD). This study aimed to assess the feasibility and efficacy of using an artificial intelligence-based chatbot to improve smile and speech in PD. Further, we explored the potential predictive value of objective face and speech parameters for motor symptoms, cognition, and mood.

METHODS

In this open-label randomized study, we collected a series of face and conversational speech samples from 20 participants with PD in weekly teleconsultation sessions for 5 months. We investigated the effect of daily chatbot conversations on smile and speech features, then we investigated whether smile and speech features could predict motor, cognitive, and mood status.

RESULTS

A repeated-measures analysis of variance revealed that the chatbot conversations had a significant interaction effect on the mean and standard deviation of the smile index during smile sections (both P = .02), maximum duration of the initial rise of the smile index (P = .04), and frequency of filler words (P = .04), but no significant interaction effects were observed for clinical measurements including motor, cognition, depression, and quality of life. Explorative analysis using statistical and machine-learning models revealed that the smile indices and several speech features were associated with motor symptoms, cognition, and mood in PD.

CONCLUSION

An artificial intelligence-based chatbot may positively affect smile and speech in PD. Smile and speech features may capture the motor, cognitive, and mental status of patients with PD.

Dopaminergic Modulation of Dynamic Emotion Perception

Emotion recognition abilities are fundamental to our everyday social interaction. A large number of clinical populations show impairments in this domain, with emotion recognition atypicalities being particularly prevalent among disorders exhibiting a dopamine system disruption (e.g., Parkinson's disease). Although this suggests a role for dopamine in emotion recognition, studies employing dopamine manipulation in healthy volunteers have exhibited mixed neural findings and no behavioral modulation. Interestingly, while a dependence of dopaminergic drug effects on individual baseline dopamine function has been well established in other cognitive domains, the emotion recognition literature so far has failed to account for these possible interindividual differences. The present within-subjects study therefore tested the effects of the dopamine D2 antagonist haloperidol on emotion recognition from dynamic, whole-body stimuli while accounting for interindividual differences in baseline dopamine. A total of 33 healthy male and female adults rated emotional point-light walkers (PLWs) once after ingestion of 2.5 mg haloperidol and once after placebo. To evaluate potential mechanistic pathways of the dopaminergic modulation of emotion recognition, participants also performed motoric and counting-based indices of temporal processing. Confirming our hypotheses, effects of haloperidol on emotion recognition depended on baseline dopamine function, where individuals with low baseline dopamine showed enhanced, and those with high baseline dopamine decreased emotion recognition. Drug effects on emotion recognition were related to drug effects on movement-based and explicit timing mechanisms, indicating possible mediating effects of temporal processing. Results highlight the need for future studies to account for baseline dopamine and suggest putative mechanisms underlying the dopaminergic modulation of emotion recognition.SIGNIFICANCE STATEMENT A high prevalence of emotion recognition difficulties among clinical conditions where the dopamine system is affected suggests an involvement of dopamine in emotion recognition processes. However, previous psychopharmacological studies seeking to confirm this role in healthy volunteers thus far have failed to establish whether dopamine affects emotion recognition and lack mechanistic insights. The present study uncovered effects of dopamine on emotion recognition in healthy individuals by controlling for interindividual differences in baseline dopamine function and investigated potential mechanistic pathways via which dopamine may modulate emotion recognition. Our findings suggest that dopamine may influence emotion recognition via its effects on temporal processing, providing new directions for future research on typical and atypical emotion recognition.