Facial expressiveness and physiological arousal in frontotemporal dementia: Phenotypic clinical profiles and neural correlates

Beauty and Paintings: Aesthetic Experience in Patients with Behavioral Variant Frontotemporal Dementia When Viewing Abstract and Concrete Paintings

We assessed the aesthetic experience of patients with behavioral variant frontotemporal dementia (bvFTD) to understand their ability to experience feelings of the sublime and to be moved when viewing paintings. We exposed patients with bvFTD and control participants to concrete and abstract paintings and asked them how moved they were by these paintings and whether the latter were beautiful or ugly. Patients with bvFTD declared being less moved than control participants by both abstract and concrete paintings. No significant differences were observed between abstract and concrete paintings in both patients with bvFTD and control participants. Patients with bvFTD provided fewer "beautiful" and more "ugly" responses than controls for both abstract and concrete paintings. No significant differences in terms of "beautiful" and "ugly" responses were observed between abstract and concrete paintings in both patients with bvFTD and control participants. These findings suggest disturbances in the basic affective experience of patients with bvFTD when they are exposed to paintings, as well as a bias in their ability to judge the aesthetic quality of paintings.

Facial expression recognition deficits in frontotemporal dementia and Alzheimer's disease: a meta-analytic investigation of effects of phenotypic variant, task modality, geographical region and symptomatic specificity

Deficits in social cognition may be present in frontotemporal dementia (FTD) and Alzheimer's disease (AD). Here, we conduct a qualitative synthesis and meta-analysis of facial expression recognition studies in which we compare the deficits between both disorders. Furthermore, we investigate the specificity of the deficit regarding phenotypic variant, domain-specificity, emotion category, task modality, and geographical region. The results reveal that both FTD and AD are associated with facial expression recognition deficits, that this deficit is more pronounced in FTD compared to AD and that this applies for the behavioral as well as for language FTD-variants, with no difference between the latter two. In both disorders, overall emotion recognition was most frequently impaired, followed by recognition of anger in FTD and by fear in AD. Verbal categorization was the most frequently used task, although matching or intensity rating tasks may be more specific. Studies from Oceania revealed larger deficits. On the other hand, non-emotional control tasks were more impacted by AD than by FTD. The present findings sharpen the social cognitive phenotype of FTD and AD, and support the use of social cognition assessment in late-life neuropsychiatric disorders.

Combined effects of transcranial direct current stimulation and aerobic exercise on inhibitory control function in healthy young adults: An event-related potential study

Transcranial direct current stimulation (tDCS) and aerobic exercise (AE) have been demonstrated to enhance inhibitory control function in healthy individuals separately. However, the potential benefits of combining these two interventions have yet to be fully explored. In this study, we aimed to use multiple event-related potential (ERP) components (P200, N200, and N450) to investigate the combined effects of tDCS and AE on the improvement of inhibitory control ability in healthy young adults. We evaluated the influence of this combined intervention on cognitive tasks involving inhibitory control function and basic information processing by performing the Stroop Word Color task. Our results showed that compared to the application of tDCS or AE alone, the combined intervention of tDCS and AE had a greater effect on improving inhibitory control function in healthy young adults. The amplitude of P200, N200, and N450 ERP components also changed more significantly during the Stroop Word Color task. We concluded that the mechanism of tDCS combined with AE in improving inhibitory control ability may involve synergistic effects on brain structures at different levels, such as regulating interactions at the reticular activating system level and activating corresponding brain regions at the medial frontal lobe and frontal lobe levels.

The neutral past: emotional (dys)regulation of autobiographical memory in behavioural variant frontotemporal dementia

BACKGROUND

While affective disturbances are a key symptomatic indicator of behavioural variant frontotemporal dementia (bvFTD), little is known about how patients process the emotional load of their autobiographical (i.e. personal) memories.

METHODS

We assessed the interplay of emotional regulation and autobiographical memory by inviting 18 bvFTD and 20 control participants to remember past personal events. For each memory, participants rated its emotional valence "then" (i.e. when the event has occurred) vs "now" (i.e. when retrieving the event).

RESULTS

Patients with bvFTD described their memories as neutral at both times (p = .85), while control participants rated their memories as more positive during "then" than during "now" (p = .013). Autobiographical retrieval triggered fewer emotional words (p < .001) and less specificity (p < .001) in bvFTD patients compared to control participants.

CONCLUSIONS

The lack of significant differences between the emotional characteristics during "then" than "now" in patients with bvFTD (and the flattening of both) may mirror their hampered ability for emotional generation, which may be associated with difficulties in reframing their past experiences to modify and adapt their meaning. The hampered emotional regulation in bvFTD may also be associated with an avoidance strategy and a passive attitude toward the past.

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.

Diminished baseline autonomic outflow in semantic dementia relates to left-lateralized insula atrophy

In semantic dementia (SD), asymmetric degeneration of the anterior temporal lobes is associated with loss of semantic knowledge and alterations in socioemotional behavior. There are two clinical variants of SD: semantic variant primary progressive aphasia (svPPA), which is characterized by predominant atrophy in the anterior temporal lobe and insula in the left hemisphere, and semantic behavioral variant frontotemporal dementia (sbvFTD), which is characterized by predominant atrophy in those structures in the right hemisphere. Previous studies of behavioral variant frontotemporal dementia, an associated clinical syndrome that targets the frontal lobes and anterior insula, have found impairments in baseline autonomic nervous system activity that correlate with left-lateralized frontotemporal atrophy patterns and disruptions in socioemotional functioning. Here, we evaluated whether there are similar impairments in resting autonomic nervous system activity in SD that also reflect left-lateralized atrophy and relate to diminished affiliative behavior. A total of 82 participants including 33 people with SD (20 svPPA and 13 sbvFTD) and 49 healthy older controls completed a laboratory-based assessment of respiratory sinus arrhythmia (RSA; a parasympathetic measure) and skin conductance level (SCL; a sympathetic measure) during a two-minute resting baseline period. Participants also underwent structural magnetic resonance imaging, and informants rated their current affiliative behavior on the Interpersonal Adjective Scale. Results indicated that baseline RSA and SCL were lower in SD than in healthy controls, with significant impairments present in both svPPA and sbvFTD. Voxel-based morphometry analyses revealed left-greater-than-right atrophy related to diminished parasympathetic and sympathetic outflow in SD. While left-lateralized atrophy in the mid-to-posterior insula correlated with lower RSA, left-lateralized atrophy in the ventral anterior insula correlated with lower SCL. In SD, lower baseline RSA, but not lower SCL, was associated with lower gregariousness/extraversion. Neither autonomic measure related to warmth/agreeableness, however. Through the assessment of baseline autonomic nervous system physiology, the present study contributes to expanding conceptualizations of the biological basis of socioemotional alterations in svPPA and sbvFTD.

Hemispheric contributions toward interoception and emotion recognition in left-vs right-semantic dementia

BACKGROUND

The hemispheric contributions toward interoception, the perception of internal bodily cues, and emotion recognition remains unclear. Semantic dementia cases with either left-dominant (i.e., left-SD) or right-dominant (i.e., right-SD) anterior temporal lobe atrophy experience emotion recognition difficulties, however, little is known about interoception in these syndromes. Here, we hypothesised that right-SD would show worse interoception and emotion recognition due to right-dominant atrophy.

METHODS

Thirty-five participants (8 left-SD; 6 right-SD; 21 controls) completed a monitoring task. Participants pressed a button when they: (1) felt their heartbeat, without pulse measurement (Interoception); or (2) heard a recorded heartbeat (Exteroception-control). Simultaneous ECG was recorded. Accuracy was calculated by comparing the event frequency (i.e., heartbeat or sound) to response frequency. Emotion recognition was assessed via the Facial Affect Selection Task. Voxel-based morphometry analyses identified neural correlates of interoception and emotion recognition.

RESULTS

Right-SD showed worse interoception than controls and left-SD (both p's < 0.001). Both patient groups showed worse emotion recognition than controls (right-SD: p < .001; left-SD: p = .018), and right-SD showed worse emotion recognition than left-SD (p = .003). Regression analyses revealed that worse emotion recognition was predicted by right-SD (p = .002), left-SD (p = .005), and impaired interoception (p = .004). Interoception and emotion were associated with the integrity of right-lateralised structures including the insula, temporal pole, thalamus, superior temporal gyrus, and hippocampus.

CONCLUSION

Our study provides the first evidence for impaired interoception in right-SD, suggesting that impaired emotion recognition in this syndrome is driven by inaccurate internal monitoring. Further we identified a common neurobiological basis for interoception and emotion in the right hemisphere.

Thinking versus feeling: How interoception and cognition influence emotion recognition in behavioural-variant frontotemporal dementia, Alzheimer's disease, and Parkinson's disease

Disease-specific mechanisms underlying emotion recognition difficulties in behavioural-variant frontotemporal dementia (bvFTD), Alzheimer's disease (AD), and Parkinson's disease (PD) are unknown. Interoceptive accuracy, accurately detecting internal cues (e.g., one's heart beating), and cognitive abilities are candidate mechanisms underlying emotion recognition. One hundred and sixty-eight participants (52 bvFTD; 41 AD; 24 PD; 51 controls) were recruited. Emotion recognition was measured via the Facial Affect Selection Task or the Mini-Social and Emotional Assessment Emotion Recognition Task. Interoception was assessed with a heartbeat detection task. Participants pressed a button each time they: 1) felt their heartbeat (Interoception); or 2) heard a recorded heartbeat (Exteroception-control). Cognition was measured via the Addenbrooke's Cognitive Examination-III or the Montreal Cognitive Assessment. Voxel-based morphometry analyses identified neural correlates associated with emotion recognition and interoceptive accuracy. All patient groups showed worse emotion recognition and cognition than controls (all P's ≤ .008). Only the bvFTD showed worse interoceptive accuracy than controls (P < .001). Regression analyses revealed that in bvFTD worse interoceptive accuracy predicted worse emotion recognition (P = .008). Whereas worse cognition predicted worse emotion recognition overall (P < .001). Neuroimaging analyses revealed that the insula, orbitofrontal cortex, and amygdala were involved in emotion recognition and interoceptive accuracy in bvFTD. Here, we provide evidence for disease-specific mechanisms for emotion recognition difficulties. In bvFTD, emotion recognition impairment is driven by inaccurate perception of the internal milieu. Whereas, in AD and PD, cognitive impairment likely underlies emotion recognition deficits. The current study furthers our theoretical understanding of emotion and highlights the need for targeted interventions.

Temporopolar regions of the human brain

Following prolonged neglect during the formative decades of behavioural neurology, the temporopolar region has become a site of vibrant research on the neurobiology of cognition and conduct. This turnaround can be attributed to increasing recognition of neurodegenerative diseases that target temporopolar regions for peak destruction. The resultant syndromes include behavioural dementia, associative agnosia, semantic forms of primary progressive aphasia and semantic dementia. Clinicopathological correlations show that object naming and word comprehension are critically dependent on the language-dominant (usually left) temporopolar region, whereas behavioural control and non-verbal object recognition display a more bilateral representation with a rightward bias. Neuroanatomical experiments in macaques and neuroimaging in humans show that the temporoparietal region sits at the confluence of auditory, visual and limbic streams of processing at the downstream (deep) pole of the 'what' pathway. The functional neuroanatomy of this region revolves around three axes, an anterograde horizontal axis from unimodal to heteromodal and paralimbic cortex; a radial axis where visual (ventral), auditory (dorsal) and paralimbic (medial) territories encircle temporopolar cortex and display hemispheric asymmetry; and a vertical depth-of-processing axis for the associative elaboration of words, objects and interoceptive states. One function of this neural matrix is to support the transformation of object and word representations from unimodal percepts to multimodal concepts. The underlying process is likely to start at canonical gateways that successively lead to generic (superordinate), specific (basic) and unique levels of recognition. A first sign of left temporopolar dysfunction takes the form of taxonomic blurring where boundaries among categories are preserved but not boundaries among exemplars of a category. Semantic paraphasias and coordinate errors in word-picture verification tests are consequences of this phenomenon. Eventually, boundaries among categories are also blurred and comprehension impairments become more profound. The medial temporopolar region belongs to the amygdalocentric component of the limbic system and stands to integrate exteroceptive information with interoceptive states underlying social interactions. Review of the pertinent literature shows that word comprehension and conduct impairments caused by temporopolar strokes and temporal lobectomy are far less severe than those seen in temporopolar atrophies. One explanation for this unexpected discrepancy invokes the miswiring of residual temporopolar neurons during the many years of indolently progressive neurodegeneration. According to this hypothesis, the temporopolar regions become not only dysfunctional but also sources of aberrant outputs that interfere with the function of areas elsewhere in the language and paralimbic networks, a juxtaposition not seen in lobectomy or stroke.

A caregiver's perspective on clinically relevant symptoms in behavioural variant frontotemporal dementia: tools for disease management and trial design

BACKGROUND

Adequate detection of symptoms and disease progression in behavioural variant frontotemporal dementia (bvFTD) is complex. Dementia cohorts usually utilize cognitive and functional measures, which fail to detect dominant behavioural and social cognitive deficits in bvFTD. Moreover, since patients typically have a loss of insight, caregivers are important informants. This is the first qualitative study to investigate caregiver relevant symptoms during the disease course of bvFTD, aiming to improve tools for diagnosis, progression, and future clinical trials.

METHODS

Informal caregivers of patients in different disease stages of bvFTD (N = 20) were recruited from the neurology outpatient clinic of the Amsterdam UMC and a patient organization for peer support in the Netherlands. Their perspectives on clinical relevance were thoroughly explored during individual semi-structured interviews. Inductive content analysis with open coding was performed by two researchers independently to establish overarching themes and patterns.

RESULTS

Caregivers reported a variety of symptoms, in which (i) loss of emotional connection, (ii) preoccupation and restlessness, and (iii) apathy and dependency compose major themes of relevance for diagnosis and treatment. Within heterogeneous disease trajectories, symptom presence differed between stages and among individuals, which is relevant in the context of progression and outcome measures. Significant socio-emotional changes dominated in early stages, while severe cognitive, behavioural, and physical deterioration shifted focus from predominant personality change to quality of life in later stages.

CONCLUSIONS

Caregiver perspectives on target symptoms in bvFTD differ according to clinical stage and patient-caregiver characteristics, with significant socio-emotional changes characterizing early stages. These findings call for more appropriate tools and symptomatic treatments, as well as a personalized approach in treatment of bvFTD and a focus on early stage interventions in clinical trial design.

Social Cognition in Behavioral Variant Frontotemporal Dementia and Pathological Subtypes: A Narrative Review

Behavioral variant frontotemporal dementia (bvFTD) belongs to the spectrum of frontotemporal lobar degeneration (FTLD) and is characterized by frontal dysfunction with executive deficits and prominent socioemotional impairments. Social cognition, such as emotion processing, theory of mind, and empathy may significantly impact daily behavior in bvFTD. Abnormal protein accumulation of tau or TDP-43 are the main causes of neurodegeneration and cognitive decline. Differential diagnosis is difficult due to the heterogeneous pathology in bvFTD and the high clinicopathological overlap with other FTLD syndromes, especially in late disease stages. Despite recent advances, social cognition in bvFTD has not yet received sufficient attention, nor has its association with underlying pathology. This narrative review evaluates social behavior and social cognition in bvFTD, by relating these symptoms to neural correlates and underlying molecular pathology or genetic subtypes. Negative and positive behavioral symptoms, such as apathy and disinhibition, share similar brain atrophy and reflect social cognition. More complex social cognitive impairments are probably caused by the interference of executive impairments due to increasing neurodegeneration. Evidence suggests that underlying TDP-43 is associated with neuropsychiatric and early social cognitive dysfunction, while patients with underlying tau pathology are marked by strong cognitive dysfunction with increasing social impairments in later stages. Despite many current research gaps and controversies, finding distinct social cognitive markers in association to underlying pathology in bvFTD is essential for validating biomarkers, for clinical trials of novel therapies, and for clinical practice.

Altered reward processing underpins emotional apathy in dementia

Introduction

While apathy is broadly defined as a loss of motivation, it is increasingly recognised as a multidimensional syndrome spanning executive, emotional, and initiation domains. Emotional apathy is purportedly driven by deficits in using socioemotional rewards to guide behaviour, yet the link between these symptoms and reward processing, and their common neural correlates, has not been directly examined.

Methods

Sixty-four patients (33 behavioural-variant frontotemporal dementia, 14 Alzheimer’s disease, 8 semantic dementia, 6 progressive nonfluent aphasia, 3 logopenic progressive aphasia) were classified into high (HEA; n = 36) and low (LEA; n = 28) emotional apathy groups based on emotional apathy subscale scores on the Dimensional Apathy Scale. Patients and age-matched healthy controls (n = 27) performed an instrumental reward learning task where they learned to associate cues with either social or monetary outcomes.

Results

HEA patients showed impaired learning on both the social and monetary reward conditions, relative to LEA patients (p = 0.016) and controls (p = 0.005). Conversely, the LEA group did not differ from controls (p = 0.925). Importantly, multiple regression analyses indicated that social reward learning significantly predicted emotional apathy. Voxel-based morphometry analyses revealed that emotional apathy and social reward learning were both associated with orbitofrontal cortex, ventral striatum, and insula atrophy.

Discussion

Our results demonstrate a unique link between impaired social reward learning and emotional apathy in dementia and reveal a shared neurobiological basis. Greater understanding of these neurocognitive mechanisms of reward processing will help improve the identification of emotional apathy in dementia and inform the development of novel interventions to address these symptoms.

Behavioral Variant Frontotemporal Dementia and Social and Criminal Transgressions

OBJECTIVE

Behavioral variant frontotemporal dementia (bvFTD) is associated with social and criminal transgressions; studies from countries around the world have documented such behavior in persons with this condition. An overview and analysis of social and criminal transgressions in bvFTD and their potential neurobiological mechanisms can provide a window for understanding the relationship of antisocial behavior and the brain.

METHODS

This review evaluated the literature on the frequency of social and criminal transgressions in bvFTD and the neurobiological disturbances that underlie them.

RESULTS

There is a high frequency of transgressions among patients with bvFTD due to impairments in neurocognition, such as social perception, behavioral regulation, and theory of mind, and impairments in social emotions, such as self-conscious emotions and empathy. Additionally, there is significant evidence for a specific impairment in an innate sense of morality. Alterations in these neurobiological processes result from predominantly right-hemisphere pathology in frontal (ventromedial, orbitofrontal, inferolateral frontal), anterior temporal (amygdala, temporal pole), limbic (anterior cingulate, amygdala), and insular regions.

CONCLUSIONS

Overlapping disturbances in neurocognition, social emotions, and moral reasoning result from disease in the mostly mesial and right-sided frontotemporal network necessary for responding emotionally to others and for behavioral control. With increased sophistication in neurobiological interventions, future goals may be the routine evaluation of these processes among individuals with bvFTD who engage in social and criminal transgressions and the targeting of these neurobiological mechanisms with behavioral, pharmacological, and other interventions.

Alleviating Surgeons' Stress through Listening to Natural Sounds in a Half-Encapsulated Rest Space after an Operation: A Pilot, Longitudinal Field Study

BACKGROUND

Natural sounds are reportedly restorative, but most research has used one-off experiments conducted in artificial conditions. Research based on field experiments is still in its infancy. This study aimed to generate hypotheses on the restorative effects of listening to natural sounds on surgeons, representing professionals working in stressful conditions.

METHODS

Each of four surgeons (two experts and two residents) participated six times in an experiment where they took a 10-min break listening to natural sounds (four times) or without natural sounds (twice) after a surgical operation. We measured their skin conductance level, an indicator of sympathetic arousal, continuously during the break (measurement occasions N = 2520) and assessed their mood using two questionnaires before and after the break (N = 69 and N = 42). We also interviewed them after the break.

RESULTS

Based on statistical Linear Mixed-Effects modeling, we developed two hypotheses for further, more detailed studies: (H1) Listening to natural sounds after an operation improves surgeons' mood. (H2) Inexperienced surgeons' tension persists so long that the effect of natural sounds on their sympathetic arousal is negligible.

CONCLUSIONS

This risk-free, easy-to-use means of stress alleviation through natural sounds could benefit highly-stressed people working indoors.

Enhanced positive emotional reactivity in frontotemporal dementia reflects left-lateralized atrophy in the temporal and frontal lobes

In frontotemporal dementia (FTD), left-lateralized atrophy patterns have been associated with elevations in certain positive emotions. Here, we investigated whether positive emotional reactivity was enhanced in semantic variant primary progressive aphasia (svPPA), an FTD syndrome that targets the left anterior temporal lobe. Sixty-one participants (16 people with svPPA, 24 people with behavioral variant FTD, and 21 healthy controls) viewed six 90-sec trials that were comprised of a series of photographs; each trial was designed to elicit a specific positive emotion, negative emotion, or no emotion. Participants rated their positive emotional experience after each trial, and their smiling behavior was coded with the Facial Action Coding System. Results indicated that positive emotional experience and smiling were elevated in svPPA in response to numerous affective and non-affective stimuli. Voxel-based morphometry analyses revealed that greater positive emotional experience and greater smiling in the patients were both associated with smaller gray matter volume in the left superior temporal gyrus (pFWE < .05), among other left-lateralized frontotemporal regions. Whereas enhanced positive emotional experience related to atrophy in middle superior temporal gyrus and structures that promote cognitive control and emotion regulation, heightened smiling related to atrophy in posterior superior temporal gyrus and structures that support motor control. Our results suggest positive emotional reactivity is elevated in svPPA and offer new evidence that atrophy in left-lateralized emotion-relevant systems relates to enhanced positive emotions in FTD.

Pupillometry as an index for cognitive processing in behavioral variant FrontoTemporal Dementia: a series of case studies

We investigated whether pupil size can variate with the intensity of cognitive processing in patients with behavioral-variant-Frontotemporal-Dementia (bvFTD). We invited five bvFTD participants and 21 controls to perform forward spans and backward spans, and, in a control condition, to count aloud. We recorded pupil activity using eye-tracking-glasses during the spans and control condition. Analysis demonstrated larger pupil sizes during backward spans than during forward spans, and larger pupil sizes during forward spans than during counting in both bvFTD and control participants. These findings demonstrate how increased cognitive load triggers increased pupil size and how this connection is maintained in bvFTD.

Exploring the Relationship Between Deficits in Social Cognition and Neurodegenerative Dementia: A Systematic Review

Background

Neurodegenerative diseases might affect social cognition in various ways depending on their components (theory of mind, emotional processing, attribution bias, and social perception) and the subtype of dementia they cause. This review aims to explore this difference in cognitive function among individuals with different aetiologies of dementia.

Methods

The following databases were explored: MEDLINE via PubMed, Cochrane Library, Lilacs, Web of Science, and PsycINFO. We selected studies examining social cognition in individuals with neurodegenerative diseases in which dementia was the primary symptom that was studied. The neurodegenerative diseases included Alzheimer's disease, Lewy body disease and frontotemporal lobar degeneration. The search yielded 2,803 articles.

Results

One hundred twenty-two articles were included in the present review. The summarised results indicate that people with neurodegenerative diseases indeed have deficits in social cognitive performance. Both in populations with Alzheimer's disease and in populations with frontotemporal dementia, we found that emotional processing was strongly affected. However, although theory of mind impairment could also be observed in the initial stages of frontotemporal dementia, in Alzheimer's disease it was only appreciated when performing highly complex task or in advanced stages of the disease.

Conclusions

Each type of dementia has a differential profile of social cognition deterioration. This review could provide a useful reference for clinicians to improve detection and diagnosis, which would undoubtedly guarantee better interventions.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020152562, PROSPERO, identifier: CRD42020152562.

THE IMPLICATIONS OF FRONTOTEMPORAL DEMENTIA FOR BRAIN DYSFUNCTION IN PSYCHOPATHY

Understanding how psychopathy compares with brain disease can help clarify its underlying mechanisms. This literature review is a broad overview of the neurobiology of psychopathic traits in comparison to behavioral variant frontotemporal dementia (bvFTD), a disorder uniquely associated with criminal behavior. In addition to violation of social norms, both psychopathy and bvFTD result in impaired socioemotional perception and empathy, impulsivity, and altered moral judgment. Despite wide areas of decreased function in psychopathy, structural changes are primarily evident in amygdala and, to a lesser extent, anterior insula, whereas in bvFTD neuropathology involves a wider paralimbic region. In psychopathy, relatively intact medial prefrontal and anterior cingulate cortices facilitate theory of mind and psychopathic traits such as deceitfulness and manipulation, bold fearlessness, and risk-taking behavior. In conclusion, many frontotemporal areas are hypoactive in psychopathy and bvFTD, but differences in dysfunctional connectivity in psychopathy vs. direct involvement in bvFTD potentially explain similarities and differences between these two conditions.

An analysis of design recommendations for socially assistive robot helpers for effective human-robot interactions in senior care

As the global population ages, there is an increase in demand for assistive technologies that can alleviate the stresses on healthcare systems. The growing field of socially assistive robotics (SARs) offers unique solutions that are interactive, engaging, and adaptable to different users’ needs. Crucial to having positive human-robot interaction (HRI) experiences in senior care settings is the overall design of the robot, considering the unique challenges and opportunities that come with novice users. This paper presents a novel study that explores the effect of SAR design on HRI in senior care through a results-oriented analysis of the literature. We provide key design recommendations to ensure inclusion for a diverse set of users. Open challenges of considering user preferences during design, creating adaptive behaviors, and developing intelligent autonomy are discussed in detail. SAR features of appearance and interaction mode along with SAR frameworks for perception and intelligence are explored to evaluate individual developments using metrics such as trust, acceptance, and intent to use. Drawing from a diverse set of features, SAR frameworks, and HRI studies, the discussion highlights robot characteristics of greatest influence in promoting wellbeing and aging-in-place of older adults and generates design recommendations that are important for future development.

The Role of Oxytocin in Social Circuits and Social Behavior in Dementia

Administration of intranasal oxytocin has been found to improve social cognition in a number of brain conditions, including autism spectrum disorder and schizophrenia. Whether this approach is relevant in dementias is currently unknown, particularly in frontotemporal dementia, a younger-onset dementia characterized clinically by marked changes in social cognition and behavior and focal atrophy of the frontal and temporal lobes. This chapter provides an overview of the deficits in social cognition in frontotemporal dementia and reviews the emerging evidence of intranasal oxytocin administration as a potential treatment option for these deficits. Future research directions will also be discussed.

Considering Hemispheric Specialization in Emotional Face Processing: An Eye Tracking Study in Left- and Right-Lateralised Semantic Dementia

Face processing relies on a network of occipito-temporal and frontal brain regions. Temporal regions are heavily involved in looking at and processing emotional faces; however, the contribution of each hemisphere to this process remains under debate. Semantic dementia (SD) is a rare neurodegenerative brain condition characterized by anterior temporal lobe atrophy, which is either predominantly left- (left-SD) or right-lateralised (right-SD). This syndrome therefore provides a unique lesion model to understand the role of laterality in emotional face processing. Here, we investigated facial scanning patterns in 10 left-SD and 6 right-SD patients, compared to 22 healthy controls. Eye tracking was recorded via a remote EyeLink 1000 system, while participants passively viewed fearful, happy, and neutral faces over 72 trials. Analyses revealed that right-SD patients had more fixations to the eyes than controls in the Fear (p = 0.04) condition only. Right-SD patients also showed more fixations to the eyes than left-SD patients in all conditions: Fear (p = 0.01), Happy (p = 0.008), and Neutral (p = 0.04). In contrast, no differences between controls and left-SD patients were observed for any emotion. No group differences were observed for fixations to the mouth, or the whole face. This study is the first to examine patterns of facial scanning in left- versus right- SD, demonstrating more of a focus on the eyes in right-SD. Neuroimaging analyses showed that degradation of the right superior temporal sulcus was associated with increased fixations to the eyes. Together these results suggest that right lateralised brain regions of the face processing network are involved in the ability to efficiently utilise changeable cues from the face.

Primary Progressive Aphasia: Toward a Pathophysiological Synthesis

PURPOSE OF REVIEW

The term primary progressive aphasia (PPA) refers to a diverse group of dementias that present with prominent and early problems with speech and language. They present considerable challenges to clinicians and researchers.

RECENT FINDINGS

Here, we review critical issues around diagnosis of the three major PPA variants (semantic variant PPA, nonfluent/agrammatic variant PPA, logopenic variant PPA), as well as considering 'fragmentary' syndromes. We next consider issues around assessing disease stage, before discussing physiological phenotyping of proteinopathies across the PPA spectrum. We also review evidence for core central auditory impairments in PPA, outline critical challenges associated with treatment, discuss pathophysiological features of each major PPA variant, and conclude with thoughts on key challenges that remain to be addressed. New findings elucidating the pathophysiology of PPA represent a major step forward in our understanding of these diseases, with implications for diagnosis, care, management, and therapies.

Frontotemporal dementias: main syndromes and underlying brain changes

PURPOSE OF REVIEW

Frontotemporal dementia (FTD) is a rare dementia, that accounts for about 15% of all dementia cases. Despite consensus diagnostic criteria, FTD remains difficult to diagnose in life because of its complex and variable clinical phenomenology and heterogeneous disorders. This review provides an update on the current knowledge of the main FTD syndromes -- the behavioural variant, semantic variant, and nonfluent/agrammatic variant-- their brain abnormalities and genetic profiles.

RECENT FINDINGS

The complexity of the clinical features in FTD has become increasingly apparent, particularly in the domain of behaviour. Such behaviour changes are now also being recognized in the language variants of FTD. Initial interest on emotion processing and social cognition is now complemented by studies on other behavioural disturbance, that spans gambling, antisocial behaviours, repetitive behaviours, and apathy. At a biological level, novel pathological subcategories continue to be identified. From a genetic viewpoint, abnormalities in three genes explain nearly three quarters of familial cases of FTD.

SUMMARY

In the absence of effective drug treatments, novel approaches are needed to target some of the most disabling features of FTD, such as language loss or behaviour disturbance. Recent interventions appear promising but will require confirmation.

Measuring Behavior and Social Cognition in FTLD

Because changes to socioemotional cognition and behavior are an early and central symptom in many of the FTLD syndromes, an objective and standardized approach to patient identification and staging relies on availability of validated socioemotional measures. Such tests should reflect functioning in key selectively vulnerable brain networks central to socioemotional behavior, specifically the intrinsically connected networks underpinning salience (SN) and semantic appraisal (SAN). There have been many challenges to the development of appropriate tests for patients with the FTLD syndromes, including the difficulty of creating standardized evaluations for the highly idiosyncratic deficits caused by salience-driven attention impairments, the trade-off between behaviorally or psychophysiologically precise measures versus the need for easily administered measures that can scale to broader clinical contexts, and the complexities of measuring socioemotional behavior across linguistically and culturally diverse samples. A subset of available socioemotional tests are reviewed with respect to evidence for their ability to reflect structural and functional changes to the FTLD-specific SN and SAN networks, and their differential diagnostic utility in the neurodegenerative disease syndromes is discussed.

Frontotemporal Dementia: A Window to Alexithymia

Alexithymia is pervasive among psychiatric patients, but its neurobiological mechanism is unclear. Patients with alexithymia cannot "read emotions," a process involving interoception, or the perception of the body's internal state, primarily in the insulae. The frontotemporal dementias are also associated with inability to correctly read emotions; hence, these dementias can provide a window into the mechanism of alexithymia. Patients with behavioral variant frontotemporal dementia (bvFTD) have a weak emotional signal with impaired emotional recognition, hypoemotionality, and decreased physiological arousal. bvFTD affects the insulae, and the weak emotional signal facilitates impaired interoceptive accuracy, resulting in an overreliance on cognitive appraisal rather than on internal sensations. In contrast, patients with semantic dementia, another frontotemporal dementia syndrome, can have intact interoception, but they have disturbed cognitive appraisal of the meaning of their bodily sensations. This "alexisomia" in semantic dementia can lead to misinterpreted somatic symptoms. Together, the findings in alexithymic patients and frontotemporal dementia syndromes support the model of impaired interoceptive accuracy as the mechanism of alexithymia, possibly from dysfunction in the insulae.

Behavioural Variant Frontotemporal Dementia: Recent Advances in the Diagnosis and Understanding of the Disorder

Frontotemporal dementia (FTD), particularly the behavioural variant (bvFTD) form, has fascinated researchers. Recent years have seen an increasing interest in aspects of bvFTD that extend beyond the initial focus on cognitive changes and frontal executive dysfunction. Changes have been identified in aspects including fundamental changes in physiology and metabolism, and cognitive domains such as episodic memory. Work on social cognition has emphasised the importance of a breakdown in interpreting and expressing emotions, while the overlap between psychiatric disorders and bvFTD has been brought into focus by the finding of high rates of psychotic features in carriers of the c9orf72 gene expansion. We review these aspects in the chapter " Behavioural variant frontotemporal dementia: Recent advances in diagnosis and understanding of the disorder" and also potential markers of disease progression and early diagnosis that may aid in the development of treatment options, which have thus far eluded us.

Degenerative dementias: Alterations of emotions and mood disorders

Degenerative dementias such as Alzheimer's disease and frontotemporal dementia result in distinct alterations in emotional processing, emotional experiences, and mood. The neuropathology of these dementias extends to structures involved in emotional processing, including the basolateral limbic network (orbitofrontal cortex, anterior temporal lobe, amygdala, and thalamus), the insula, and ventromedial frontal lobe. Depression is the most common emotion and mood disorder affecting patients with Alzheimer's disease. The onset of depression can be a prodromal sign of this dementia. Anxiety can also be present early in the course of Alzheimer's disease and especially among patients with early-onset forms of the disease. In contrast, patients with behavioral variant frontotemporal dementia demonstrate hypoemotionality, deficits in the recognition of emotion, and decreased psychophysiological reactivity to emotional stimuli. They typically have a disproportionate impairment in emotional and cognitive empathy. One other unique feature of behavioral variant frontotemporal dementia is the frequent occurrence of bipolar disorder. The management strategies for these alterations of emotion and mood in degenerative dementias primarily involve the judicious use of the psychiatric armamentarium of medications.

EEG-Based Emotion Classification for Alzheimer's Disease Patients Using Conventional Machine Learning and Recurrent Neural Network Models

As the number of patients with Alzheimer's disease (AD) increases, the effort needed to care for these patients increases as well. At the same time, advances in information and sensor technologies have reduced caring costs, providing a potential pathway for developing healthcare services for AD patients. For instance, if a virtual reality (VR) system can provide emotion-adaptive content, the time that AD patients spend interacting with VR content is expected to be extended, allowing caregivers to focus on other tasks. As the first step towards this goal, in this study, we develop a classification model that detects AD patients' emotions (e.g., happy, peaceful, or bored). We first collected electroencephalography (EEG) data from 30 Korean female AD patients who watched emotion-evoking videos at a medical rehabilitation center. We applied conventional machine learning algorithms, such as a multilayer perceptron (MLP) and support vector machine, along with deep learning models of recurrent neural network (RNN) architectures. The best performance was obtained from MLP, which achieved an average accuracy of 70.97%; the RNN model's accuracy reached only 48.18%. Our study results open a new stream of research in the field of EEG-based emotion detection for patients with neurological disorders.

Social cognition impairment in genetic frontotemporal dementia within the GENFI cohort

A key symptom of frontotemporal dementia (FTD) is difficulty interacting socially with others. Social cognition problems in FTD include impaired emotion processing and theory of mind difficulties, and whilst these have been studied extensively in sporadic FTD, few studies have investigated them in familial FTD. Facial Emotion Recognition (FER) and Faux Pas (FP) recognition tests were used to study social cognition within the Genetic Frontotemporal Dementia Initiative (GENFI), a large familial FTD cohort of C9orf72, GRN, and MAPT mutation carriers. 627 participants undertook at least one of the tasks, and were separated into mutation-negative healthy controls, presymptomatic mutation carriers (split into early and late groups) and symptomatic mutation carriers. Groups were compared using a linear regression model with bootstrapping, adjusting for age, sex, education, and for the FP recognition test, language. Neural correlates of social cognition deficits were explored using a voxel-based morphometry (VBM) study. All three of the symptomatic genetic groups were impaired on both tasks with no significant difference between them. However, prior to onset, only the late presymptomatic C9orf72 mutation carriers on the FER test were impaired compared to the control group, with a subanalysis showing differences particularly in fear and sadness. The VBM analysis revealed that impaired social cognition was mainly associated with a left hemisphere predominant network of regions involving particularly the striatum, orbitofrontal cortex and insula, and to a lesser extent the inferomedial temporal lobe and other areas of the frontal lobe. In conclusion, theory of mind and emotion processing abilities are impaired in familial FTD, with early changes occurring prior to symptom onset in C9orf72 presymptomatic mutation carriers. Future work should investigate how performance changes over time, in order to gain a clearer insight into social cognitive impairment over the course of the disease.

Physiological correlates of subjective emotional valence and arousal dynamics while viewing films

An exploration of the physiological correlates of subjective emotional states has theoretical and practical significance. Previous studies have reported that subjective valence and arousal correspond to facial electromyography (EMG) and electrodermal activity (EDA), respectively, across stimuli. However, the reported results were inconsistent, no study investigated subjective-physiological concordance across time, and measures of arousal remain controversial. To investigate these issues, while healthy adults (n = 20) viewed emotional films, we assessed overall and continuous ratings of valence and arousal and recorded EMG from the corrugator supercilii and zygomatic major, EDA from the palms and forehead, and nose-tip temperature. The corrugator and zygomatic EMG were negatively and positively associated with valence ratings, respectively, across stimuli and time. EDA (both sites) and nose-tip temperature were positively and negatively associated with arousal ratings, respectively, across stimuli and time. It is concluded that subjective emotional valence and arousal dynamics have specific physiological correlates.

Interactions between decision-making and emotion in behavioral-variant frontotemporal dementia and Alzheimer's disease

Negative and positive emotions are known to shape decision-making toward more or less impulsive responses, respectively. Decision-making and emotion processing are underpinned by shared brain regions including the ventromedial prefrontal cortex (vmPFC) and the amygdala. How these processes interact at the behavioral and brain levels is still unclear. We used a lesion model to address this question. Study participants included individuals diagnosed with behavioral-variant frontotemporal dementia (bvFTD, n = 18), who typically present deficits in decision-making/emotion processing and atrophy of the vmPFC, individuals with Alzheimer’s disease (AD, n = 12) who present with atrophy in limbic structures and age-matched healthy controls (CTRL, n = 15). Prior to each choice on the delay discounting task participants were cued with a positive, negative or neutral picture and asked to vividly imagine witnessing the event. As hypothesized, our findings showed that bvFTD patients were more impulsive than AD patients and CTRL and did not show any emotion-related modulation of delay discounting rate. In contrast, AD patients showed increased impulsivity when primed by negative emotion. This increased impulsivity was associated with reduced integrity of bilateral amygdala in AD but not in bvFTD. Altogether, our results indicate that decision-making and emotion interact at the level of the amygdala supporting findings from animal studies.

Physiological, behavioral and subjective sadness reactivity in frontotemporal dementia subtypes

Frontotemporal dementia (FTD), a neurodegenerative disease broadly characterized by socioemotional impairments, includes three clinical subtypes: behavioral variant FTD (bvFTD), semantic variant primary progressive aphasia (svPPA) and non-fluent variant primary progressive aphasia (nfvPPA). Emerging evidence has shown emotional reactivity impairments in bvFTD and svPPA, whereas emotional reactivity in nfvPPA is far less studied. In 105 patients with FTD (49 bvFTD, 31 svPPA and 25 nfvPPA) and 27 healthy controls, we examined three aspects of emotional reactivity (physiology, facial behavior and subjective experience) in response to a sad film. In a subset of the sample, we also examined the neural correlates of diminished aspects of reactivity using voxel-based morphometry. Results indicated that all three subtypes of FTD showed diminished physiological responding in respiration rate and diastolic blood pressure; patients with bvFTD and svPPA also showed diminished subjective experience, and no subtypes showed diminished facial behavior. Moreover, there were differences among the clinical subtypes in brain regions where smaller volumes were associated with diminished sadness reactivity. These results show that emotion impairments extend to sadness reactivity in FTD and underscore the importance of considering different aspects of sadness reactivity in multiple clinical subtypes for characterizing emotional deficits and associated neurodegeneration in FTD.

Psychological and Cognitive Markers of Behavioral Variant Frontotemporal Dementia-A Clinical Neuropsychologist's View on Diagnostic Criteria and Beyond

Behavioral variant frontotemporal dementia (bvFTD) is the second leading cognitive disorder caused by neurodegeneration in patients under 65 years of age. Characterized by frontal, insular, and/or temporal brain atrophy, patients present with heterogeneous constellations of behavioral and psychological symptoms among which progressive changes in social conduct, lack of empathy, apathy, disinhibited behaviors, and cognitive impairments are frequently observed. Since the histopathology of the disease is heterogeneous and identified genetic mutations only account for ~30% of cases, there are no reliable biomarkers for the diagnosis of bvFTD available in clinical routine as yet. Early detection of bvFTD thus relies on correct application of clinical diagnostic criteria. Their evaluation however, requires expertise and in-depth assessments of cognitive functions, history taking, clinical observations as well as caregiver reports on behavioral and psychological symptoms and their respective changes. With this review, we aim for a critical appraisal of common methods to access the behavioral and psychological symptoms as well as the cognitive alterations presented in the diagnostic criteria for bvFTD. We highlight both, practical difficulties as well as current controversies regarding an overlap of symptoms and particularly cognitive impairments with other neurodegenerative and primary psychiatric diseases. We then review more recent developments and evidence on cognitive, behavioral and psychological symptoms of bvFTD beyond the diagnostic criteria which may prospectively enhance the early detection and differential diagnosis in clinical routine. In particular, evidence on specific impairments in social and emotional processing, praxis abilities as well as interoceptive processing in bvFTD is summarized and potential links with behavior and classic cognitive domains are discussed. We finally outline both, future opportunities and major challenges with regard to the role of clinical neuropsychology in detecting bvFTD and related neurocognitive disorders.