Impaired facial emotion recognition in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS): Side and age at onset matters

Reduced eye gaze fixation during emotion recognition among patients with temporal lobe epilepsy

OBJECTIVES

To investigate the facial scan patterns during emotion recognition (ER) through the dynamic facial expression task and the awareness of social interference test (TASIT) using eye tracking (ET) technology, and to find some ET indicators that can accurately depict the ER process, which is a beneficial supplement to existing ER assessment tools.

METHOD

Ninety-six patients with TLE and 88 healthy controls (HCs) were recruited. All participants watched the dynamic facial expression task and TASIT including a synchronized eye movement recording and recognized the emotion (anger, disgust, happiness, or sadness). The accuracy of ER was recorded. The first fixation time, first fixation duration, dwell time, and fixation count were selected and analyzed.

RESULTS

TLE patients exhibited ER impairment especially for disgust (Z =  - 3.391; p = 0.001) and sadness (Z =  - 3.145; p = 0.002). TLE patients fixated less on the face, as evidenced by the reduced fixation count (Z =  - 2.549; p = 0.011) of the face and a significant decrease in the fixation count rate (Z =  - 1.993; p = 0.046). During the dynamic facial expression task, TLE patients focused less on the eyes, as evidenced by the decreased first fixation duration (Z =  - 4.322; p = 0.000), dwell time (Z =  - 4.083; p = 0.000), and fixation count (Z =  - 3.699; p = 0.000) of the eyes.

CONCLUSION

TLE patients had ER impairment, especially regarding negative emotions, which may be attributable to their reduced fixation on the eyes during ER, and the increased fixation on the mouth could be a compensatory effect to improve ER performance. Eye-tracking technology could provide the process indicators of ER, and is a valuable supplement to traditional ER assessment tasks.

Revisiting emotion recognition in different types of temporal lobe epilepsy: The influence of facial expression intensity

Temporal lobe epilepsy (TLE) can induce various difficulties in recognizing emotional facial expressions (EFE), particularly for negative valence emotions. However, these difficulties have not been systematically examined according to the localization of the epileptic focus. For this purpose, we used a forced-choice recognition task in which faces expressing fear, sadness, anger, disgust, surprise, or happiness were presented in different intensity levels from moderate to high intensity. The first objective of our study was to evaluate the impact of emotional intensity on the recognition of different categories of EFE in TLE patients compared to control participants. The second objective was to assess the effect of localizationof epileptic focus on the recognition of EFE in patients with medial temporal lobe epilepsy (MTLE) associated or not with hippocampal sclerosis (HS), or lateral temporal lobe epilepsy (LTLE). The results showed that the 272 TLE patients and the 68 control participants were not differently affected by the intensity of EFE. However, we obtained group differences within the clinical population when we took into account the localization of the temporal lobe epileptic focus. As predicted, TLE patients were impaired in recognizing fear and disgust relative to controls. Moreover, the scores of these patients varied according to the localization of the epileptic focus, but not according to the cerebral lateralization of TLE. The facial expression of fear was less well recognized by MTLE patients, with or without HS, and the expression of disgust was less well recognized by LTLE as well as MTLE without HS patients. Moreover, emotional intensity modulated differently the recognition of disgust and surprise of the three patient groups underlying the relevance of using moderate emotional intensity to distinguish the effect of epileptic focus localization. These findings should be taken into account for interpreting the emotional behaviors and deserve to befurther investigated before considering TLE surgical treatment or social cognition interventions in TLE patients.

Anterior temporal lobectomy improved mood status and quality of life in Chinese patients with mesial temporal lobe epilepsy: a single-arm cohort study

BACKGROUND

Many studies have emphasized that selective resection of epileptic lesions in temoral lobe is associated with better preservation of cognition function; whether this applies to patients with refractory mesial temporal lobe epilepsy (MTLE) remains unknown. The objective of this study was to evaluate changes in cognitive functions, mood status, and quality of life after anterior temporal lobectomy in patients with refractory MTLE.

METHODS

This single-arm cohort study assessed cognitive function, mood status, and quality of life, as well as electroencephalography findings, in patients with refractory MTLE who underwent anterior temporal lobectomy at Xuanwu Hospital from January 2018 to March 2019. Pre- and post-operative characteristics were compared to evaluate the effects of surgery.

RESULTS

Anterior temporal lobectomy significantly reduced the frequencies of epileptiform discharges. The overall success rate of surgery was acceptable. Anterior temporal lobectomy did not result in significant changes in overall cognitive functions (P   >  0.05), although changes in certain domains, including visuospatial ability, executive ability, and abstract thinking, were detected. Anterior temporal lobectomy resulted in improvements in anxiety and depression symptoms and quality of life.

CONCLUSIONS

Anterior temporal lobectomy reduced epileptiform discharges and incidence of post-operative seizures as well as resulted in improved mood status and quality of life without causing significant changes in cognitive function.

Social Cognition in Temporal and Frontal Lobe Epilepsy: Systematic Review, Meta-analysis, and Clinical Recommendations

OBJECTIVE

Despite the importance of social cognitive functions to mental health and social adjustment, examination of these functions is absent in routine assessment of epilepsy patients. Thus, this review aims to provide a comprehensive overview of the literature on four major aspects of social cognition among temporal and frontal lobe epilepsy, which is a critical step toward designing new interventions.

METHOD

Papers from 1990 to 2021 were reviewed and examined for inclusion in this study. After the deduplication process, a systematic review and meta-analysis of 44 and 40 articles, respectively, involving 113 people with frontal lobe epilepsy and 1482 people with temporal lobe epilepsy were conducted.

RESULTS

Our results indicated that while patients with frontal or temporal lobe epilepsy have difficulties in all aspects of social cognition relative to nonclinical controls, the effect sizes were larger for theory of mind (g = .95), than for emotion recognition (g = .69) among temporal lobe epilepsy group. The frontal lobe epilepsy group exhibited significantly greater impairment in emotion recognition compared to temporal lobe. Additionally, people with right temporal lobe epilepsy (g =  1.10) performed more poorly than those with a left-sided (g = .90) seizure focus, specifically in the theory of mind domain.

CONCLUSIONS

These data point to a potentially important difference in the severity of deficits within the emotion recognition and theory of mind abilities depending on the laterlization of seizure side. We also suggest a guide for the assessment of impairments in social cognition that can be integrated into multidisciplinary clinical evaluation for people with epilepsy.

Toward social neuropsychology of epilepsy: a meta-analysis on social cognition in epilepsy phenotypes and a critical narrative review on assessment methods

Background

The aim of this review is to (a) characterize social cognition impairments in the domains of emotion recognition (ER) and theory of mind (ToM) in patients with epilepsy and (b) to review assessment tools with a focus on their validity and usability in clinical practice.

Methods

An electronic search for clinical studies investigating social cognition in epilepsy populations vs healthy control subjects (HC) yielded 53 studies for the meta-analysis and descriptive review.

Results

Results suggest that (1) social cognition is significantly impaired in patients with temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE) and patients with epilepsy not originating within the temporal or frontal lobes including idiopathic generalized epilepsies (eTLE/eFLE); (2) there is no significant difference between eTLE/eFLE and TLE regarding ER, while TLE and FLE patients perform worse than those with eTLE/eFLE, without significant differences between FLE and TLE regarding ToM ability. A descriptive analysis of the most commonly used assessment tools and stimulus material in this field revealed a lack of ecological validity, usability, and economic viability for everyday clinical practice.

Conclusions

Our meta-analysis shows that patients with epilepsy are at a significantly increased risk of deficits in social cognition. However, the underlying multifactorial mechanisms remain unclear. Future research should therefore specifically address the impairment of processing and methodological problems of testing.

Theory of mind and facial emotion recognition in adults with temporal lobe epilepsy: A meta-analysis

BACKGROUND

Mounting studies have investigated impairments in social cognitive domains (including theory of mind [ToM] and facial emotion recognition [FER] in adult patients with temporal lobe epilepsy (TLE). However, to date, inconsistent findings remain.

METHODS

A search of PubMed, Web of Science, and Embase databases was conducted until December 2021. Hedges g effect sizes were computed with a random-effects model. Meta-regressions were used to assess the potential confounding factors of between-study variability in effect sizes.

RESULTS

The meta-analysis included 41 studies, with a combined sample of 1,749 adult patients with TLE and 1,324 healthy controls (HCs). Relative to HCs, adult patients with TLE showed large impairments in ToM (g = -0.92) and cognitive ToM (g = -0.92), followed by medium impairments in affective ToM (g = -0.79) and FER (g = -0.77). Besides, no (statistically) significant differences were observed between the magnitude of social cognition impairment in adult with TLE who underwent and those who did not undergo epilepsy surgery. Meta-regressions exhibited that greater severity of executive functioning was associated with more severe ToM defects, and older age was associated with more severe FER defects.

CONCLUSIONS

Results of this meta-analysis suggest that adult patients with TLE show differential impairments in the core aspects of social cognitive domains (including ToM and FER), which may help in planning individualized treatment with appropriate cognitive and behavioral interventions.

Emotion recognition and theory of mind after temporal lobe epilepsy surgery: A systematic review

In order to navigate in our complex social world successfully, it is crucial to maintain and practice cognitive skills that are dedicated to adaptive social functioning. Emerging evidence suggests that besides deficits in declarative memory, executive functions, and language, impairments in social cognition (SC, e.g., emotion recognition, theory of mind) are also present in temporal lobe epilepsy (TLE). The organic and psycho-social consequences of epilepsy surgery might have additional implications regarding this deficit. Here we qualitatively synthesize longitudinal and cross-sectional findings on SC after TLE surgery. A literature search using PubMed and Scopus identified 275 potential articles. Studies were eligible if they (1) included patients with a diagnosis of TLE, (2) included a healthy comparison group, (3) reported original research, (4) were published in peer-reviewed journals and in English language, (5) reported the intervention of epilepsy surgery. Articles that (1) were case studies, (2) did not focus on SC abilities, (3) used interviews or self-report questionnaires to examine SC functions were excluded. A total of 16 original studies assessing emotion recognition (ER) and/or theory of mind (ToM) matched our criteria. The literature suggests that neither ER nor ToM abilities change after surgery: post-surgery patients show similar impairment patterns to pre-surgery patients. Nevertheless, individual improvement or decline could be masked by group comparisons and results should be considered in light of methodological heterogeneity among studies.

The Effects of Dynamic and Static Emotional Facial Expressions of Humans and Their Avatars on the EEG: An ERP and ERD/ERS Study

This study aimed to examine whether the cortical processing of emotional faces is modulated by the computerization of face stimuli ("avatars") in a group of 25 healthy participants. Subjects were passively viewing 128 static and dynamic facial expressions of female and male actors and their respective avatars in neutral or fearful conditions. Event-related potentials (ERPs), as well as alpha and theta event-related synchronization and desynchronization (ERD/ERS), were derived from the EEG that was recorded during the task. All ERP features, except for the very early N100, differed in their response to avatar and actor faces. Whereas the N170 showed differences only for the neutral avatar condition, later potentials (N300 and LPP) differed in both emotional conditions (neutral and fear) and the presented agents (actor and avatar). In addition, we found that the avatar faces elicited significantly stronger reactions than the actor face for theta and alpha oscillations. Especially theta EEG frequencies responded specifically to visual emotional stimulation and were revealed to be sensitive to the emotional content of the face, whereas alpha frequency was modulated by all the stimulus types. We can conclude that the computerized avatar faces affect both, ERP components and ERD/ERS and evoke neural effects that are different from the ones elicited by real faces. This was true, although the avatars were replicas of the human faces and contained similar characteristics in their expression.

Familial mesial temporal lobe epilepsy in Mexico: Inheritance pattern and clinical features

PURPOSE

The objectives of this study were to determine the inheritance pattern by which familial mesial temporal lobe epilepsy (FMTLE) is segregated in Mexican families, and to identify if there was an association between the clinical characteristics and the inheritance pattern.

METHOD

We included a total of 25 families with two or more members affected with MTLE during two years and elaborated a family pedigree for each family. The inheritance pattern was classified as autosomal dominant (AD) or autosomal recessive (AR), considering the affected members. We used statistical analysis association and differences between clinical characteristics and inheritance patterns.

RESULTS

The affected families with the AD pattern were 15.7 fold times more likely to start seizures at 5 years of age or earlier than families with AR pattern, OR = 15.7 (IC 95% = 1.9-128.9). We observed a predominance and greater déjà vu association (64.4% vs 31.3%; p = 0.021), OR = 3.9 (CI 95% = 1.1-13.5) in patients with AD versus AR pattern. Finally, we identified that patients with AD pattern had a likelihood of presenting emotional alterations 5.6 times higher than AR (OR = 5.6, IC = 1.1-27.5).

CONCLUSION

FMTLE is a heterogeneous syndrome, both phenotypically and genotypically; thus, our findings may be helpful for clinical use to perform an early diagnosis, to provide timely treatment, and to prevent comorbidities associated to this disease. However, in order to identify the possible genetic causes underlying these inheritance patterns, the use of molecular studies is necessary.

Social cognition and executive functions in children and adolescents with focal epilepsy

OBJECTIVES

Deficits in facial emotion recognition and Theory of Mind are frequent in patients with epilepsy. Although this evidence, studies on pediatric age are few and the relation between these abilities and other cognitive domain remains to be better elucidated. The purpose of our study is to evaluate facial emotion recognition and Theory of Mind in children and adolescents with focal epilepsy, and correlate them with intelligence and executive functions.

MATERIALS AND METHODS

Our work is a cross-sectional observational study. Sixty-two children and adolescents aged between 7-16 years diagnosed by focal epilepsy and 32 sex/age-matched controls were recruited. All participants were administered a standardized battery tests to assess social cognition (NEPSY-II), executive functions (EpiTrack Junior) and cognitive non-verbal level (Raven Progressive Matrices).

RESULTS

Emotion recognition mean score was significantly lower in the epilepsy group than in the controls to Student's t-test (p<0.05). Epilepsy group showed an impairment in happiness, sadness, anger and fear recognition, compared to controls (p<0.05). Theory of Mind mean score was also significantly lower in epilepsy group than controls (p<0.05). Deficits in emotion recognition seemed to be related to low age at onset of epilepsy, long duration of disease, low executive functions and low non-verbal intelligence. Deficits in Theory of Mind seemed to be related to a high seizure frequency.

CONCLUSIONS

Our results suggest that children and adolescents with focal epilepsy had deficit in facial emotion recognition and Theory of Mind, compared to their peer. Both these difficulties seem to be related to some features of epilepsy itself. Our results also suggest that deficits in facial emotion recognition are potentially related to difficulties in executive functions and non-verbal intelligence. More studies are needed to confirm these hypotheses.

Social cognition and psychopathology in childhood and adolescence

There is a substantial body of research on social cognition in adults with epilepsy, and in broad categories such as focal and generalized epilepsies, but much less has been written about social cognition in children with epilepsy (CWE), and in childhood-onset epilepsy syndromes specifically. In several of these syndromes, autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD), two disorders with social cognitive impairments, are reported. There is strong evidence for social cognitive deficits in juvenile myoclonic epilepsy (JME). There is also a considerable amount of evidence for such deficits in a number of syndromes that may be associated with ASD or ADHD, including West syndrome (WS), Dravet syndrome (DS), and the Landau-Kleffner syndrome (LKS). However, the evidence is of variable quality and incomplete across the range of childhood epilepsy syndromes. In some syndromes, childhood epilepsy substantially increases the risk of severe social cognitive impairment, which may persist after the seizures remit. This paper presents an overview of current research on social cognition in childhood epilepsy, with a particular focus on syndromes with a high prevalence of autistic and behavioral comorbidities. Social cognitive impairments represent a considerable additional challenge for patients and caregivers. Early diagnosis and intervention might significantly improve long-term social cognitive outcomes, highlighting the need for greater awareness among clinicians of this important topic. This article is part of the Special Issue "Epilepsy and social cognition across the lifespan".

Subjective and physiological response to emotions in temporal lobe epilepsy and psychogenic non-epileptic seizures

BACKGROUND

Temporal lobe epilepsy (TLE) and psychogenic non-epileptic seizures (PNES) are conditions frequently associated with dysfunction in emotional regulation leading to increased risk of affective disorders. This study investigates emotional processing with an objective measure of emotional reactivity in patients with TLE and patients with PNES.

METHODS

34 patients with TLE and 14 patients with PNES were evaluated on skin conductance responses (SCR) to emotions induced by short films and compared to 34 healthy controls. An attention and a suppression condition were performed while viewing the films.

RESULTS

The both groups of patients disclosed lower SCR to emotions compared to controls, mainly in suppression condition. While TLE patients had lower SCR in attention condition than controls for fear, sadness and happiness, PNES had lower SCR only for happiness. In suppression condition, both had lower SCR than controls except for peacefulness in both groups and sadness in PNES. Subjective evaluations revealed that both patient's groups scored a higher intensity for sadness than controls in attention and lower for in fear and disgust in suppression only in TLE.

LIMITATIONS

The sample size in the PNES group and the lack of a control group with similar levels of mood symptoms limited the interpretation of our results.

CONCLUSION

As no correlation were found between SCR to emotions and scores of affective disorders, this pattern of responses might be underpinned by specific pathophysiological and cognitive mechanisms related to TLE and to PNES. Thus, therapeutic approaches targeting emotional autonomic responses can be of interest in the management of these conditions.

Facial emotion perception in patients with epilepsy: A systematic review with meta-analysis

Facial emotion perception is a fundamental social competency relying on a specialised, yet distributed, neural network. This review aimed to determine whether patients with epilepsy have facial emotion perception accuracy impairments overall, or for a subset of emotions (anger, disgust, happiness, sadness, fear, and surprise), and the relationship to epilepsy type, demographic/treatment variables, and brain organisation. Database searches used PRISMA guidelines with strict inclusion/exclusion criteria. Thirty included studies assessed patients with temporal lobe (TLE; n=709), frontocentral (FCE; n=22), and genetic generalised (GGE; n=48) epilepsy. Large deficits emerged in patients with epilepsy compared to controls (n=746; Hedges' g=0.908-1.076). Patients with TLE were significantly impaired on all emotions except surprise; patients with GGE were significantly impaired in anger, disgust, and fear perception. Meta-regression of patients with TLE revealed younger age at testing was associated with lower accuracy. This review provides evidence for marked global deficits of emotion perception in epilepsy, with differential emotion-specific impairment patterns in patients with TLE and GGE.

Social cognition in temporal lobe epilepsy: A systematic review and meta-analysis

OBJECTIVE

There is increasing evidence suggesting that social cognitive abilities are impaired in temporal lobe epilepsy (TLE), the most common form of focal epilepsies.

METHODS

In this meta-analysis, 31 studies investigating theory of mind (ToM) and facial emotion recognition performances of 1356 patients with TLE (351 postsurgery) and 859 healthy controls were included.

RESULTS

Patients with TLE had significant deficits in ToM (d = 0.73–0.89) and recognition of facial emotions. There were no significant differences in severity of social cognitive deficits between patients with TLE with or without medial temporal lobectomy. Earlier onset of seizures was associated with ToM impairment. Right-sided TLE was associated with more severe deficits in recognition of fear, sadness, and disgust.

CONCLUSIONS

Social cognitive information processing is impaired in TLE, and the potential role of these deficits in functional impairment needs to be further investigated.

Right fronto-limbic atrophy is associated with reduced empathy in refractory unilateral mesial temporal lobe epilepsy

Refractory mesial temporal lobe epilepsy (MTLE) is the most frequent focal epilepsy and is often accompanied by deficits in social cognition including emotion recognition, theory of mind, and empathy. Consistent with the neuronal networks that are crucial for normal social-cognitive processing, these impairments have been associated with functional changes in fronto-temporal regions. However, although atrophy in unilateral MTLE also affects regions of the temporal and frontal lobes that underlie social cognition, little is known about the structural correlates of social-cognitive deficits in refractory MTLE. In the present study, a psychometrically validated empathy questionnaire was combined with whole-brain voxel-based morphometry (VBM) to investigate the relationship between self-reported affective and cognitive empathy and gray matter volume in 55 subjects (13 patients with right MTLE, 9 patients with left MTLE, and 33 healthy controls). Consistent with the brain regions underlying social cognition, our results show that lower affective and cognitive empathy was associated with smaller volume in predominantly right fronto-limbic regions, including the right hippocampus, parahippocampal gyrus, thalamus, fusiform gyrus, inferior temporal gyrus, dorsomedial and dorsolateral prefrontal cortices, and in the bilateral midbrain. The only region that was associated with both affective and cognitive empathy was the right mesial temporal lobe. These findings indicate that patients with right MTLE are at increased risk for reduced empathy towards others' internal states and they shed new light on the structural correlates of impaired social cognition frequently accompanying refractory MTLE. In line with previous evidence from patients with neurodegenerative disease and stroke, the present study suggests that empathy depends upon the integrity of right fronto-limbic and brainstem regions and highlights the importance of the right mesial temporal lobe and midbrain structures for human empathy.

Right mesial temporal lobe epilepsy impairs empathy-related brain responses to dynamic fearful faces

Unilateral mesial temporal lobe epilepsy (MTLE) has been associated with reduced amygdala responsiveness to fearful faces. However, the effect of unilateral MTLE on empathy-related brain responses in extra-amygdalar regions has not been investigated. Using functional magnetic resonance imaging, we measured empathy-related brain responses to dynamic fearful faces in 34 patients with unilateral MTLE (18 right sided), in an epilepsy (extra-MTLE; n = 16) and in a healthy control group (n = 30). The primary finding was that right MTLE (RMTLE) was associated with decreased activity predominantly in the right amygdala and also in bilateral periaqueductal gray (PAG) but normal activity in the right anterior insula. The results of the extra-MTLE group demonstrate that these reduced amygdala and PAG responses go beyond the attenuation caused by antiepileptic and antidepressant medication. These findings clearly indicate that RMTLE affects the function of mesial temporal and midbrain structures that mediate basic interoceptive input necessary for the emotional awareness of empathic experiences of fear. Together with the decreased empathic concern found in the RMTLE group, this study provides neurobehavioral evidence that patients with RMTLE are at increased risk for reduced empathy towards others' internal states and sheds new light on the nature of social-cognitive impairments frequently accompanying MTLE.

Increased stathmin expression strengthens fear conditioning in epileptic rats

Patients with temporal lobe epilepsy have inexplicable fear attack as the aura. However, the underlying neural mechanisms of seizure-modulated fear are not clarified. Recent studies identified stathmin as one of the key controlling molecules in learning and innate fear. Stathmin binds to tubulin, inhibits microtubule assembly and promotes microtubule catastrophes. Therefore, stathmin is predicted to play a crucial role in the association of epilepsy seizures with fear conditioning. Firstly, a pilocarpine model of epilepsy in rats was established, and subsequently the fear condition training was performed. The epileptic rats with fear conditioning (epilepsy + fear) had a much longer freezing time compared to each single stimulus. The increased freezing levels revealed a significantly strengthened effect of the epileptic seizures on the learned fear of the tone-shock contextual. Subsequently, the stathmin expression was compared in the hippocampus, the amygdale, the insular cortex and the temporal lobe. The significant change of stathmin expression occurred in the insular and the hippocampus, but not in the amygdale. Stathmin expression and dendritic microtubule stability were compared between fear and epilepsy in rats. Epilepsy was found to strengthen the fear conditioning with increased expression of stathmin and a decrease in microtubule stability. Fear conditioning slightly increased the expression of stathmin, whereas epilepsy with fear conditioning increased it significantly in the hippocampus, insular cortex and hypothalamus. The phosphorylated stathmin slightly increased in the epilepsy with fear conditioning. The increased expression of stathmin was contrary to the decrease of the stathmin microtubule-associated protein (MAP2) and α-tubulin in the epileptic rats with fear conditioning in all three areas of the brain. The most significant change of the ratio of MAP2 and α-tubulin/stathmin occurred in the insular cortex and hippocampus. In conclusion, epilepsy can strengthen the fear conditioning with increased stathmin and decreased microtubule stability, particularly in the insular cortex and hippacampus. Therefore, the insular cortex may play a more important role between fear and epilepsy.

Mapping epileptic activity: sources or networks for the clinicians?

Epileptic seizures of focal origin are classically considered to arise from a focal epileptogenic zone and then spread to other brain regions. This is a key concept for semiological electro-clinical correlations, localization of relevant structural lesions, and selection of patients for epilepsy surgery. Recent development in neuro-imaging and electro-physiology and combinations, thereof, have been validated as contributory tools for focus localization. In parallel, these techniques have revealed that widespread networks of brain regions, rather than a single epileptogenic region, are implicated in focal epileptic activity. Sophisticated multimodal imaging and analysis strategies of brain connectivity patterns have been developed to characterize the spatio-temporal relationships within these networks by combining the strength of both techniques to optimize spatial and temporal resolution with whole-brain coverage and directional connectivity. In this paper, we review the potential clinical contribution of these functional mapping techniques as well as invasive electrophysiology in human beings and animal models for characterizing network connectivity.

Recognition of facial emotions and identity in patients with mesial temporal lobe and idiopathic generalized epilepsy: an eye-tracking study

PURPOSE

To describe visual scanning pattern for facial identity recognition (FIR) and emotion recognition (FER) in patients with idiopathic generalized (IGE) and mesial temporal lobe epilepsy (MTLE). Secondary endpoint was to correlate the results with cognitive function.

METHODS

Benton Facial Recognition Test (BFRT) and Ekman&Friesen series were performed for FIR and FER respectively in 23 controls, 20 IGE and 19 MTLE patients. Eye movements were recorded by a Hi-Speed eye-tracker system. Neuropsychological tools explored cognitive function.

RESULTS

Correct FIR rate was 78% in controls, 70.7% in IGE and 67.4% (p=0.009) in MTLE patients. FER hits reached 82.7% in controls, 74.3% in IGE (p=0.006) and 73.4% in MTLE (p=0.002) groups. IGE patients failed in disgust (p=0.005) and MTLE ones in fear (p=0.009) and disgust (p=0.03). FER correlated with neuropsychological scores, particularly verbal fluency (r=0.542, p<0.001). Eye-tracking revealed that controls scanned faces more diffusely than IGE and MTLE patients for FIR, who tended to top facial areas. A longer scanning of the top facial area was found in the three groups for FER. Gap between top and bottom facial region fixation time decreased in MTLE patients, with more but shorter fixations in bottom facial region. However, none of these findings were statistically significant.

CONCLUSION

FIR was impaired in MTLE patients, and FER in both IGE and MTLE, particularly for fear and disgust. Although not statistically significant, those with impaired FER tended to perform more diffuse eye-tracking over the faces and have cognitive dysfunction.

Empathy and emotion recognition in patients with idiopathic generalized epilepsy

Patients with epilepsy have deficits in social cognition. In this study, we examined the changes in empathy and eye emotion recognition using the Interpersonal Reactivity Index and eye emotion recognition tasks. Forty-two patients with idiopathic generalized epilepsy and 47 healthy controls were involved. The eye emotion recognition and cognitive empathy abilities of the patients with IGE were impaired, but the affective empathy was intact. The cognitive empathy performance of the patients with IGE was positively correlated with their performance in sadness recognition, MoCA, verbal fluency, and the Stroop test. These results suggest that the empathy ability was impaired in patients with IGE, and this impairment may be caused by deficits in frontal lobe function.

Social inference deficits in temporal lobe epilepsy and lobectomy: risk factors and neural substrates

In temporal lobe epilepsy and lobectomy, deficits in emotion identification have been found consistently, but there is limited evidence for complex social inference skills such as theory of mind. Furthermore, risk factors and the specific neural underpinnings of these deficits in this population are unclear. We investigated these issues using a comprehensive range of social inference tasks (emotion identification and comprehension of sincere, deceitful and sarcastic social exchanges) in individuals with temporal lobe epilepsy or lobectomy (n = 87). We observed deficits across patient groups which were partly related to the presence of mesial temporal lobe sclerosis, early age of seizure onset and left lobectomy. A voxel-based morphometry analysis conducted in the pre-operative group confirmed the importance of the temporal lobe by showing a relationship between left hippocampal atrophy and overall social inference abilities, and between left anterior neocortex atrophy and sarcasm comprehension. These findings are in keeping with theoretical proposals that the hippocampus is critical for binding diverse elements in cognitive domains beyond canonical episodic memory operations, and that the anterior temporal cortex is a convergence zone of higher-order perceptual and emotional processes, and of stored representations. As impairments were frequent, we require further investigation of this behavioural domain and its impact on the lives of people with epilepsy.

The affective value of faces in patients achieving long-term seizure freedom after temporal lobectomy

We investigated different aspects of facial expression evaluation in a homogeneous cohort of 42 seizure-free patients with 5 or more years of follow-up after temporal lobectomy (TL), with the aim of further characterizing the impairment in emotion and social cognition among patients. A group of healthy subjects matched for sex, age, and education served as controls. Four tasks of facial expression evaluation were used: (a) facial expression recognition, (b) rating of the intensity of facial expression, and (c) rating of valence (pleasantness) and (d) rating of arousal induced by facial expressions. Patients had a worse performance in the recognition task for all negative emotions, while no differences in intensity ratings were found. They also reported lower arousal ratings than controls for faces showing fear, anger, disgust, and neutral expressions, as well as lower valence ratings for all facial expressions except those showing happiness. Longer epilepsy duration before TL was negatively associated with ratings of arousal and intensity and positively associated with valence ratings for fearful facial expressions. This study showed that patients who become seizure-free after TL present long-term deficits in several aspects of facial expression evaluation. Longitudinal, prospective studies are needed to evaluate if social cognition improves or declines after TL.

Ambiguous emotion recognition in temporal lobe epilepsy: the role of expression intensity

The lateralization of emotion processing is currently debated and may be further explored by examining facial expression recognition (FER) impairments in temporal lobe epilepsy (TLE). Furthermore, there is also debate in the literature whether FER deficits in individuals with TLE are more pronounced in the right than in the left hemisphere. Individuals with TLE were tested with an FER task designed to be more sensitive than those classically used to shed light on this issue. A total of 25 right- and 32 left-TLE patients, candidates for surgery, along with controls, underwent an FER task composed of stimuli shown not only at full-blown intensities (100 %), but also morphed to lower-intensity display levels (35 %, 50 %, and 75 %). The results showed that, as compared to controls, right-TLE patients showed deficits in the recognition of all emotional categories. Furthermore, when considering valence, right-TLE patients were impaired only in negative emotion recognition, but no deficits for positive emotions were highlighted in left-TLE patients. Finally, only the right-TLE patients' impairment was found to be related to the age of epilepsy onset. Our work demonstrates that the FER deficits in TLE span multiple emotional categories and show manifestations dependent on the laterality of the epileptic focus. Taken together, our findings provide the strongest evidence for the right-hemisphere model, but they also partially support the valence model. We suggest that current models are not exhaustive at explaining emotional-processing cerebral control, and further that multistep models should be developed.

Lesion side matters - an fMRI study on the association between neural correlates of watching dynamic fearful faces and their evaluation in patients with temporal lobe epilepsy

Most studies assessing facial affect recognition in patients with TLE reported emotional disturbances in patients with TLE. Results from the few fMRI studies assessing neural correlates of affective face processing in patients with TLE are divergent. Some, but not all, found asymmetrical mesiotemporal activations, i.e., stronger activations within the hemisphere contralateral to seizure onset. Little is known about the association between neural correlates of affect processing and subjective evaluation of the stimuli presented. Therefore, we investigated the neural correlates of processing dynamic fearful faces in 37 patients with mesial temporal lobe epilepsy (TLE; 18 with left-sided TLE (lTLE), 19 with right-sided TLE (rTLE)) and 20 healthy subjects. We additionally assessed individual ratings of the fear intensity and arousal perception of the fMRI stimuli and correlated these data with the activations induced by the fearful face paradigm and activation lateralization within the mesiotemporal structures (in terms of individual lateralization indices, LIs). In healthy subjects, whole-brain analysis showed bilateral activations within a widespread network of mesial and lateral temporal, occipital, and frontal areas. The patient groups activated different parts of this network. In patients with lTLE, we found predominantly right-sided activations within the mesial and lateral temporal cortices and the superior frontal gyrus. In patients with rTLE, we observed bilateral activations in the posterior regions of the lateral temporal lobe and within the occipital cortex. Mesiotemporal region-of-interest analysis showed bilateral symmetric activations associated with watching fearful faces in healthy subjects. According to the region of interest and LI analyses, in the patients with lTLE, mesiotemporal activations were lateralized to the right hemisphere. In the patients with rTLE, we found left-sided mesiotemporal activations. In patients with lTLE, fear ratings were comparable to those of healthy subjects and were correlated with relatively stronger activations in the right compared to the left amygdala. Patients with rTLE showed significantly reduced fear ratings compared to healthy subjects, and we did not find associations with amygdala lateralization. Although we found stronger activations within the contralateral mesial temporal lobe in the majority of all patients, our results suggest that only in the event of left-sided mesiotemporal damage is the right mesial temporal lobe able to preserve intact facial fear recognition. In the event of right-sided mesiotemporal damage, fear recognition is disturbed. This underlines the hypothesis that the right amygdala is biologically predisposed to processing fear, and its function cannot be fully compensated in the event of right-sided mesiotemporal damage.

Resting state networks in temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is typically described as a neurologic disorder affecting a cerebral network comprising the hippocampus proper and several anatomically related extrahippocampal regions. A new level of complexity was recently added to the study of this disorder by the evidence that TLE also appears to chronically alter the activity of several brain-wide neural networks involved in the control of higher order brain functions and not traditionally linked to epilepsy. Recently developed brain imaging techniques such as functional magnetic resonance imaging (fMRI) analysis of resting state connectivity, have greatly contributed to these observations by allowing the precise characterization of several brain networks with distinct functional signatures in the resting brain, and therefore also known as "resting state networks." These significant advances in imaging represent an opportunity to investigate the still elusive origins of the disabling cognitive and psychiatric manifestations of TLE, and could have important implications for its pathophysiology and, perhaps, its therapy. Herein we review recent studies in this field by focusing on resting state networks that have been implicated in the pathophysiology of psychiatric disorders and cognitive impairment in patients with epilepsy: the default mode network, the attention network, and the reward/emotion network.

A critical evaluation of the lateralizing significance of material-specific memory deficits in patients with mesial temporal lobe epilepsy with hippocampal sclerosis

To critically assess the value of material-specific memory deficits in lateralizing temporal lobe dysfunction preoperatively, we compared the neuropsychological data of 50 consecutive patients with unilateral mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS; right: 31, left: 19) with those of 50 age- and education-matched healthy control subjects. On case-control comparison, both the subcohorts with left and right MTLE-HS performed poorly on intelligence tests, in addition to individual memory tests. However, comparison of the verbal and visual memory functions between subcohorts with right and left MTLE-HS revealed that learning trials and delayed word list recall were the only tests that hypothesized left temporal lobe dysfunction. We conclude that material-specific memory deficits are largely test driven, but there is a lateralizing role for task-specific deficits in left MTLE-HS. Although neuropsychological data help to define baseline neuropsychological impairment, caution should be exercised in interpreting the lateralizing value of material-specific memory deficits prior to surgery.

Hippocampal sclerosis of aging, a prevalent and high-morbidity brain disease

Hippocampal sclerosis of aging (HS-Aging) is a causative factor in a large proportion of elderly dementia cases. The current definition of HS-Aging rests on pathologic criteria: neuronal loss and gliosis in the hippocampal formation that is out of proportion to AD-type pathology. HS-Aging is also strongly associated with TDP-43 pathology. HS-Aging pathology appears to be most prevalent in the oldest-old: autopsy series indicate that 5-30 % of nonagenarians have HS-Aging pathology. Among prior studies, differences in study design have contributed to the study-to-study variability in reported disease prevalence. The presence of HS-Aging pathology correlates with significant cognitive impairment which is often misdiagnosed as AD clinically. The antemortem diagnosis is further confounded by other diseases linked to hippocampal atrophy including frontotemporal lobar degeneration and cerebrovascular pathologies. Recent advances characterizing the neurocognitive profile of HS-Aging patients have begun to provide clues that may help identify living individuals with HS-Aging pathology. Structural brain imaging studies of research subjects followed to autopsy reveal hippocampal atrophy that is substantially greater in people with eventual HS-Aging pathology, compared to those with AD pathology alone. Data are presented from individuals who were followed with neurocognitive and neuroradiologic measurements, followed by neuropathologic evaluation at the University of Kentucky. Finally, we discuss factors that are hypothesized to cause or modify the disease. We conclude that the published literature on HS-Aging provides strong evidence of an important and under-appreciated brain disease of aging. Unfortunately, there is no therapy or preventive strategy currently available.

A more realistic approach, using dynamic stimuli, to test facial emotion recognition impairment in temporal lobe epilepsy

To explore potentially impaired social functioning in patients with mesial temporal lobe epilepsy (MTLE), we evaluated facial emotion recognition (FER) using dynamic facial stimuli. We evaluated FER in 88 patients with MTLE, including 25 posttemporal lobectomy (PTL) patients, when they watched videos of actors expressing the six basic emotions of happiness, sadness, anger, fear, surprise, and disgust. Thirty-two healthy subjects were examined as controls. The relationships between task, performance, and neurophysiological and radiological variables potentially affecting the ability to recognize moving facial emotions were examined by multivariate analysis. Both the patients with MTLE and the PTL subset demonstrated significantly impaired FER compared with healthy controls. Of the six emotions, they showed impaired recognition of sadness, fear, and disgust. Facial emotion recognition was impaired in patients with chronic MTLE, particularly those with bilateral damage. Failure to recognize emotional expressions, particularly fear, disgust, and sadness, may contribute to difficulties in social functioning and relationship building.

Emotion processing bias and age of seizure onset among epilepsy patients with depressive symptoms

The current study examined whether mood-congruent biases in emotion processing extend to epilepsy patients with depressive symptoms and the potentially moderating effects of age of seizure onset on these biases. In addition, we examined associations between depression (Beck Depression Inventory - 2nd Edition; BDI-II) and quality of life (Quality of Life in Epilepsy - 10-item questionnaire; QOLIE-10). Data from 101 epilepsy patients were analyzed, including 61 females and 40 males. Measures included the Comprehensive Affect Testing System - Abbreviated (CATS-A), from which indices of mood-congruent bias were derived. A significant interaction between BDI-II raw scores and age of seizure onset was found for mood-congruent bias scores in the facial affect modality (β=-0.24, p<.03). Beck Depression Inventory - 2nd Edition raw scores were significantly and positively correlated with quality of life (QOLIE-10; r=.69, p<.01). Results of the current study show that epilepsy patients with an early age of seizure onset may be most at risk for mood-congruent biases when experiencing depressive symptoms and that such symptoms have real-world implications for quality of life for persons living with epilepsy.

Hemispheric asymmetries and prosodic emotion recognition deficits in Parkinson's disease

While Parkinson's disease (PD) has traditionally been described as a movement disorder, there is growing evidence of cognitive and social deficits associated with the disease. However, few studies have looked at multi-modal social cognitive deficits in patients with PD. We studied lateralization of both prosodic and facial emotion recognition (the ability to recognize emotional valence from either tone of voice or from facial expressions) in PD. The Comprehensive Affect Testing System (CATS) is a well-validated test of human emotion processing that has been used to study emotion recognition in several major clinical populations, but never before in PD. We administered an abbreviated version of CATS (CATS-A) to 24 medicated PD participants and 12 age-matched controls. PD participants were divided into two groups, based on side of symptom onset and unilateral motor symptom severity: left-affected (N = 12) or right-affected PD participants (N = 12). CATS-A is a computer-based button press task with eight subtests relevant to prosodic and facial emotion recognition. Left-affected PD participants with inferred predominant right-hemisphere pathology were expected to have difficulty with prosodic emotion recognition since there is evidence that the processing of prosodic information is right-hemisphere dominant. We found that facial emotion recognition was preserved in the PD group, however, left-affected PD participants had specific impairment in prosodic emotion recognition, especially for sadness. Selective deficits in prosodic emotion recognition suggests that (1) hemispheric effects in emotion recognition may contribute to the impairment of emotional communication in a subset of people with PD and (2) the coordination of neural networks needed to decipher temporally complex social cues may be specifically disrupted in PD.

Recognition of emotions from faces and voices in medial temporal lobe epilepsy

Patients with chronic medial temporal lobe epilepsy (MTLE) can be impaired in different tasks that evaluate emotional or social abilities. In particular, the recognition of facial emotions can be affected (Meletti S, Benuzzi F, Rubboli G, et al. Neurology 2003;60:426-31. Meletti S, Benuzzi F, Cantalupo G, Rubboli G, Tassinari CA, Nichelli P. Epilepsia 2009;50:1547-59). To better understand the nature of emotion recognition deficits in MTLE we investigated the decoding of basic emotions in the visual (facial expression) and auditory (emotional prosody) domains in 41 patients. Results showed deficits in the recognition of both facial and vocal expression of emotions, with a strong correlation between performances across the two tasks. No correlation between emotion recognition and measures of IQ, quality of life (QOLIE-31), and depression (Beck Depression Inventory) was significant, except for a weak correlation between prosody recognition and IQ. These data suggest that emotion recognition impairment in MTLE is not dependent on the sensory channel through which the emotional stimulus is transmitted. Moreover, these findings support the notion that emotional processing is at least partly independent of measures of cognitive intelligence.