Implicit Sensitivity to Disgust-inducing Stimuli in Self-neglect FTD Patients

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.

TD: The case of Diogenes Syndrome-deficit or denial?

Diogenes Syndrome (DS) is characterised by extreme self-neglect, domestic squalor, hoarding, social withdrawal, and lack of concern and shame for the individual's residential situation. This paper describes TD who was unable to identify emotional expressions of disgust and was borderline-impaired for facial recognition associated with perceptual difficulties. Problems interpreting expressions of disgust were interesting as TD was living in squalor, neglecting himself, and lacked concern for his circumstances. This led us to question whether the basis of his difficulties were neuropsychological or psychological in nature, which became the objective of this study, with a focus on shame and disgust. TD completed neuropsychological and psychological assessments alongside an experimental task investigating processing of disgust and his living situation. Results highlighted executive dysfunction but understanding of living with the consequences of squalor was spared as was emotion based decision-making. Assessment indicated difficulties with olfactory processing and aspects of interoceptive awareness. TD showed poor awareness of his living conditions and a lack of shame. Disgust sensitivity was unimpaired. It is unclear if TD's difficulties were caused by psychological or neuropsychological impairments, although both likely play a part. Further research is required to understand processes underpinning DS, particularly disgust and shame.

Ugly aesthetic perception associated with emotional changes in experience of art by behavioural variant of frontotemporal dementia patients

The aesthetic experience through art is a window into the study of emotions. Patients with behavioural variant of frontotemporal dementia (bvFTD) have early alteration of emotional processing. A new appreciation of art has been reported in some of these patients. We designed a computerized task using 32 abstract paintings that allowed us to investigate the integrity of patients' emotions when viewing the artwork. We evaluated both conscious and explicit appraisal of emotions [aesthetic judgment (beautiful/ugly), emotional relevance (affected or not by the painting), emotional valence (pleasant/unpleasant), emotional reaction (adjective choice) and arousal] and unconscious processing. Fifteen bvFTD patients and 15 healthy controls were included. BvFTD patients reported that they were "little touched" by the paintings. Aesthetic judgment was very different between the two groups: the paintings were considered ugly (negative aesthetic bias) and unpleasant (negative emotional bias) more often by the patients than by controls. Valence and aesthetic judgments correlated in both groups. In addition, there was a positive bias in the implicit task and for explicit emotional responses. Patients frequently chose the word "sad" and rarely expressed themselves with such adjectives as "happy". Our results suggest that bvFTD patients can give an aesthetic judgment, but present abstraction difficulties, as spectators, resulting from impairments in the cognitive processes involved. They also have difficulties in terms of emotional processes with the loss of the ability to feel the emotion per se (i.e., to feel an emotion faced with art) linked to behaviour assessment. This cognitive approach allows us to better understand which spectators are bvFTD patients and to show interactions between emotions and behavioural disorders.

Processing emotion from abstract art in frontotemporal lobar degeneration

art may signal emotions independently of a biological or social carrier: it might therefore constitute a test case for defining brain mechanisms of generic emotion decoding and the impact of disease states on those mechanisms. This is potentially of particular relevance to diseases in the frontotemporal lobar degeneration (FTLD) spectrum. These diseases are often led by emotional impairment despite retained or enhanced artistic interest in at least some patients. However, the processing of emotion from art has not been studied systematically in FTLD. Here we addressed this issue using a novel emotional valence matching task on abstract paintings in patients representing major syndromes of FTLD (behavioural variant frontotemporal dementia, n=11; sematic variant primary progressive aphasia (svPPA), n=7; nonfluent variant primary progressive aphasia (nfvPPA), n=6) relative to healthy older individuals (n=39). Performance on art emotion valence matching was compared between groups taking account of perceptual matching performance and assessed in relation to facial emotion matching using customised control tasks. Neuroanatomical correlates of art emotion processing were assessed using voxel-based morphometry of patients' brain MR images. All patient groups had a deficit of art emotion processing relative to healthy controls; there were no significant interactions between syndromic group and emotion modality. Poorer art emotion valence matching performance was associated with reduced grey matter volume in right lateral occopitotemporal cortex in proximity to regions previously implicated in the processing of dynamic visual signals. Our findings suggest that abstract art may be a useful model system for investigating mechanisms of generic emotion decoding and aesthetic processing in neurodegenerative diseases.

Impaired emotional processing in a patient with a left posterior insula-SII lesion

The present case-report investigated the influence of a lesion in the left posterior insula-SII cortices on the processing of emotions. MB and 16 normal controls explicitly rated the valence and the intensity of both facial expressions and emotional words. In addition, they had to perform a number comparison task and a lexical decision task without focusing their attention on emotional components of stimuli. MB identified the valence of emotional words as well as the control group. Nevertheless, she provided higher intensity scores for disgusted words and her responses in the lexical decision task were significantly delayed for these stimuli. In addition, MB's response times were not differently influenced by the presence of irrelevant emotional faces. However, she explicitly identified fewer facial expressions of disgust and she assessed them as significantly less intense. This pattern of results contributes to highlight the psychological and behavioral disorders observed after a left posterior insular stroke.

Diminished disgust reactivity in behavioral variant frontotemporal dementia

Frontotemporal dementia is a neurodegenerative disease that impacts emotion and social behavior. Using laboratory measures of emotional reactivity, our past work has found that reactivity to loud noises and to thematically simple happy and sad emotional films are preserved in the early stages of the disease while other emotional responses (e.g., embarrassment) are severely compromised. In the present study we examined disgust, an emotion whose function is to distance us from offending objects and situations. We measured disgust reactivity in 21 patients with behavioral variant frontotemporal dementia (bvFTD, a subtype of frontotemporal dementia characterized by emotional blunting) and 25 neurologically healthy controls. Disgust is an emotion of particular interest in bvFTD, due to caregiver and clinician reports that patients engage in acts that suggest this emotion may be compromised; in addition, the pattern of neurodegeneration in bvFTD includes atrophy of key frontotemporal structures (e.g., anterior insula) with known roles in visceral emotions such as disgust. In the present study, participants had their emotional facial behavior, physiology, and self-reported emotional experience measured while watching a disgust-eliciting film. We found that behavioral, physiological, and self-reported experiential responses were all reduced in bvFTD patients compared to controls (with behavioral and physiological differences still found after controlling for patients' cognitive deficits). We discuss the implications of these findings for bvFTD patients' problems in social functioning and their typical patterns of neurodegeneration.

Living in squalor: neuropsychological function, emotional processing and squalor perception in patients found living in squalor

BACKGROUND

Patients living in squalor have a wide range of psychiatric diagnoses, but these may have a common neural basis involving frontal systems. This study investigated frontal executive function, theory of mind, emotional processing including disgust, and appreciation of squalor in elderly patients found living in squalor.

METHODS

Six patients referred to an old age psychiatry service underwent a battery of neuropsychological tests, assessment of living conditions and awareness of self and others' squalor.

RESULTS

All six patients showed impairment in frontal executive function, typically accompanied by amnesic deficits. Theory of mind and emotional processing were surprisingly preserved. While five of the patients could recognize severely unclean or cluttered living conditions in newspaper photographs, more than half did not appreciate that their own living conditions were squalid.

CONCLUSION

Deficits in frontal executive function appear important in the genesis of squalor although functions linked to orbito-frontal ability appear preserved.