Facial emotion impairment in multiple sclerosis is linked to modifying observation strategies of emotional faces.

BACKGROUND: Facial emotion recognition (FER) may be impaired in patients with multiple sclerosis (MS). Nevertheless, the literature is heterogeneous, with studies not highlighting this kind of impairment. Moreover, most studies have not explored differences between MS spectrum disorders (radiologically isolated syndrome (RIS), clinically-isolated syndrome (CIS), relapsing-remitting (RRMS), and progressive (primary - (PPMS) and secondary - (SPMS)). One hypothesis would be that FER impairment results from an alteration of eye-gaze strategies while observing emotional faces. Consequently, a FER deficit would be found in MS patients for whom these observation strategies would be disturbed and more frequent in the progressive forms. METHODS: We prospectively enroled 52 patients (10 RIS, 10 CIS, 12RRMS, 10 SPMS, 10 PPMS) and 23 healthy controls (HC) to assess FER using Ekman Faces Test. Eye movements (number and duration of fixations) were recorded with an eye-tracking device. RESULTS: 21% of the MS participants had significant FER impairment. This impairment was observed in all phenotypes. In progressive forms, FER impairment was more frequent, more severe, and associated with modified emotional face observation strategies. MS participants with significant FER impairment had significantly more modification of eye-gaze strategies during observation of expressive faces than MS participants without FER impairment. CONCLUSION: FER impairment seems to be linked to a deficit of attention orientation in MS. Remediation of eye-gaze strategies during observation of emotional faces could be beneficial, as observed in other neurological diseases.

Eye-gaze Strategies During Facial Emotion Recognition in Neurodegenerative Diseases and Links With Neuropsychiatric Disorders.

BACKGROUND: Facial emotion recognition (FER) is primarily and severely impaired in individuals with the behavioral variant of frontotemporal dementia (bvFTD) and is often mildy impaired in individuals with Alzheimer disease (AD) or Parkinson disease (PD). Such impairment is associated with inappropriate social behaviors. OBJECTIVE: To determine whether FER impairment is linked to the use of inappropriate eye-gaze strategies to decode facial emotions, leading to misinterpretation of others' intentions and then to behavioral disorders. METHOD: We assessed FER in 9 individuals with bvFTD, 23 with AD, and 20 with PD, as well as 22 healthy controls (HC), using the Reading the Mind in the Eyes (RME) Test and the Ekman Faces Test. Eye movements (number and duration of fixations) were recorded with an eye-tracking device. Behavior was assessed using the Neuropsychiatric Inventory. RESULTS: FER was mildly impaired in the AD and PD groups and severely impaired in the bvFTD group. FER impairment was accompanied by an increase in the number of fixations and a more attracted gaze toward the lower part of one's face. FER impairment and an increase in the number of fixations were positively correlated with behavioral disorders. CONCLUSION: Our study demonstrated a link between FER impairment, modification of eye-gaze strategies during the observation of emotional faces, and behavioral disorders in individuals with bvFTD and those with AD or PD. These results suggest that an eye-gaze strategy rehabilitation program could have beneficial effects on emotion recognition and behavioral disorders in individuals with these diseases.

[Theory of mind, empathy and eye gaze strategies during an artwork observation in neurodegenerative pathologies]. / Théorie de l'esprit, empathie et stratégies de regard durant l'observation d'une œuvre d'art dans les pathologies neurodégénératives.

OBJECTIVE: Theory of mind (ToM) and empathy are severely impaired in the behavioral-variant of frontotemporal dementia (bvFTD) and more mildly in Alzheimer's (AD) and Parkinson's diseases (PD). Such impairments are associated with behavioral disorders (BD). Modification of visual scanning strategies of complex visual scenes is also found in these pathologies. We hypothesized that these patients applied atypical gaze strategies when observing social events, which would not allow to properly process social cues and would result in the production of erroneous inferences and lack of empathy towards others. METHODS: Fifty-five participants were divided into four groups: five bvFTD, 19 AD, 17 PD and 14 matched controls subjects. ToM and empathy were assessed by eye movements recording (eye-tracking) and by a questionnaire during a painting observation. Scores obtained were compared between each group and to social cognition reference tests, and correlated to the NeuroPsychiatric Inventory. RESULTS: Our paradigm was suitable for assessing cognitive ToM while it lacked sensitivity for empathy assessment. Severe ToM impairment was highlighted in bvFTD while milder difficulties were observed in AD and for PD. bvFTD and AD groups produced erroneous inferences from cognitive mental states. ToM performances were linked to visual exploration strategies of the painting. Atypical visual observation was highlighted in bvFTD and AD groups causing a time shift in perspective taking of the character. Finally, we have highlighted that social cognition performances, gaze strategies and BD were correlated. CONCLUSION: The observation of a painting in association with eye-tracking technology can be a good support for social cognition assessment. We highlighted a link between atypical visual scanning strategies, ToM impairment and BD in these pathologies. ToM skills could be improved by training in the search for visual social cues. Therefore, this kind of remediation could have positive effects on BD.

Regional brain stem atrophy in idiopathic Parkinson's disease detected by anatomical MRI.

Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder characterized by the dysfunction of dopaminergic dependent cortico-basal ganglia loops and diagnosed on the basis of motor symptoms (tremors and/or rigidity and bradykinesia). Post-mortem studies tend to show that the destruction of dopaminergic neurons in the substantia nigra constitutes an intermediate step in a broader neurodegenerative process rather than a unique feature of Parkinson's disease, as a consistent pattern of progression would exist, originating from the medulla oblongata/pontine tegmentum. To date, neuroimaging techniques have been unable to characterize the pre-symptomatic stages of PD. However, if such a regular neurodegenerative pattern were to exist, consistent damages would be found in the brain stem, even at early stages of the disease. We recruited 23 PD patients at Hoenn and Yahr stages I to II of the disease and 18 healthy controls (HC) matched for age. T1-weighted anatomical scans were acquired (MPRAGE, 1 mm3 resolution) and analyzed using an optimized VBM protocol to detect white and grey matter volume reduction without spatial a priori. When the HC group was compared to the PD group, a single cluster exhibited statistical difference (p<0.05 corrected for false detection rate, 4287 mm3) in the brain stem, between the pons and the medulla oblongata. The present study provides in-vivo evidence that brain stem damage may be the first identifiable stage of PD neuropathology, and that the identification of this consistent damage along with other factors could help with earlier diagnosis in the future. This damage could also explain some non-motor symptoms in PD that often precede diagnosis, such as autonomic dysfunction and sleep disorders.