Personality, Alzheimer's disease and behavioural and cognitive symptoms of dementia: the PACO prospective cohort study protocol

International audienceBACKGROUND: Alzheimer's disease is characterised by a loss of cognitive function and behavioural problems as set out in the term "Behavioural and Psychological Symptoms of Dementia". These behavioural symptoms have heavy consequences for the patients and their families. A greater understanding of behavioural symptoms risk factors would allow better detection of those patients, a better understanding of crisis situations and better management of these patients. Some retrospective studies or simple observations suggested that personality could play a role in the occurrence of behavioural symptoms. Finally, performance in social cognition like facial recognition and perspective taking could be linked to certain personality traits and the subsequent risks of behavioural symptoms. We propose to clarify this through a prospective, multicentre, multidisciplinary study. Main Objective: -To assess the effect of personality and life events on the risk of developing behavioural symptoms. Secondary Objectives: -To evaluate, at the time of inclusion, the connection between personality and performance in social cognition tests; -To evaluate the correlation between performance in social cognition at inclusion and the risks of occurrence of behavioural symptoms; -To evaluate the correlation between regional cerebral atrophy, using brain Magnetic Resonance Imaging at baseline, and the risk of behavioural symptoms.METHODS/DESIGN: Study type and Population: Prospective multicentre cohort study with 252 patients with Alzheimer's disease at prodromal or mild dementia stage. The inclusion period will be of 18 months and the patients will be followed during 18 months. The initial evaluation will include: a clinical and neuropsychological examination, collection of behavioural symptoms data (Neuropsychiatric-Inventory scale) and their risk factors, a personality study using both a dimensional (personality traits) and categorical approach, an inventory of life events, social cognition tests and an Magnetic Resonance Imaging. Patients will be followed every 6 months (clinical examination and collection of behavioural symptoms data and risk factors) during 18 months.DISCUSSION: This study aims at better identifying the patients with Alzheimer's disease at high risk of developing behavioural symptoms, to anticipate, detect and quickly treat these disorders and so, prevent serious consequences for the patient and his caregivers.TRIAL REGISTRATION: ClincalTrials.gov: NCT01297140

De la représentation des émotions en mémoire (arguments théoriques et expérimentaux en faveur de l'hypothèse d'une double représentation émotionnelle en mémoire à long-terme)

L'objectif de nos recherches était d'étudier l'organisation des connaissances émotionnelles en mémoire à long-terme (MLT) en nous situant dans un modèle épisodique de la MLT. Nous avons utilisé le paradigme d'amorçage comme outil d'investigation. Dans une première série d'expériences, la relation amorce-cible et le délai entre la présentation de l'amorce et de la cible (SOA) étaient manipulés. Des effets d'amorçage émotionnels à court-terme ont été observés quels que soient le type de tâche émotionnelle et la population expérimentale (jeune, âgée ou patient Alzheimer) mais variaient en fonction du SOA et de la connotation des amorces. Ces résultats ont été interprétés en termes de double représentation de l'émotion en MLT, l'une purement émotionnelle, l'autre dérivée des propriétés sémantiques des stimuli, en termes de différence qualitative entre les émotions négatives et positives, en termes de préservation de l'activation automatique émotionnelle chez les patients DTA et en termes de déficit précoce de l'hémisphère gauche chez ces patients. Dans une seconde série d'expériences, les participants étaient confrontés à deux phases expérimentales. Dans une première phase, les participants devaient émettre une évaluation émotionnelle sur des stimuli cibles verbaux ou non verbaux présentés soit seuls, soit superposés à une image neutre ou émotionnelle. Dans une seconde phase (phase test), les participants étaient soumis soit à une catégorisation émotionnelle sur les stimuli cibles, soit à une catégorisation de genre, soit à une dénomination. Des effets d'amorçage à long-terme et des effets de l'image sur le traitement des stimuli en phase test ont été observés et variaient en fonction du type de stimuli-cibles et du type de tâches. Ces résultats ont été interprétés en termes de différence qualitative entre deux types de représentations émotionnelles et confirment l'hypothèse d'une influence spécifique de chacune de ces connaissances sur le fonctionnement cognitif.LYON2/BRON-BU (690292101) / SudocSudocFranceF

L’enfant Zèbre et le lapin : apport de la médiation assistée par le lapin

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Prefrontal cortex and impulsivity : interest of noninvasive brain stimulation

Introduction: Impulsivity has been reported in many psychiatric conditions and includes deficits in several cognitive functions such as attention, inhibitory control, risk taking, delay discounting and planning. Many studies have shown that noninvasive brain stimulation (NIBS) techniques modulate the activity of the prefrontal cortex and the functions involved in impulsivity. Objective: This article aims to review the literature on the effect of NIBS on impulsivity in healthy subjects aged 18–65 years old, and to highlight research avenues to develop therapeutic alternatives for such disorders. Method: We performed a systematic review of the literature in the PubMed database following PRISMA method with “transcranial magnetic stimulation”, “repetitive transcranial magnetic stimulation”, “transcranial direct current stimulation”, “inhibition”, “risk”, “impulsive behavior”, “attention”, “reward”, “delay discounting”, “delay task”, “planning”, “prefrontal cortex” as key words. Results: We selected fifty-six studies showing modulation of the cognitive functions involved in impulsivity through NIBS. Conclusions: The data led us to consider new therapeutic alternatives in impulsive disorders by modulating prefrontal cortex activity through NIBS

Neuroanatomical Correlates of Recognizing Face Expressions in Mild Stages of Alzheimer's Disease

Early Alzheimer's disease can involve social disinvestment, possibly as a consequence of impairment of nonverbal communication skills. This study explores whether patients with Alzheimer's disease at the mild cognitive impairment or mild dementia stage have impaired recognition of emotions in facial expressions, and describes neuroanatomical correlates of emotion processing impairment. As part of the ongoing PACO study (personality, Alzheimer's disease and behaviour), 39 patients with Alzheimer's disease at the mild cognitive impairment or mild dementia stage and 39 matched controls completed tests involving discrimination of four basic emotions-happiness, fear, anger, and disgust-on photographs of faces. In patients, automatic volumetry of 83 brain regions was performed on structural magnetic resonance images using MAPER (multi-atlas propagation with enhanced registration). From the literature, we identified for each of the four basic emotions one brain region thought to be primarily associated with the function of recognizing that emotion. We hypothesized that the volume of each of these regions would be correlated with subjects' performance in recognizing the associated emotion. Patients showed deficits of basic emotion recognition, and these impairments were correlated with the volumes of the expected regions of interest. Unexpectedly, most of these correlations were negative: better emotional facial recognition was associated with lower brain volume. In particular, recognition of fear was negatively correlated with the volume of amygdala, disgust with pallidum, and happiness with fusiform gyrus. Recognition impairment in mild stages of Alzheimer's disease for a given emotion was thus associated with less visible atrophy of functionally responsible brain structures within the patient group. Possible explanations for this counterintuitive result include neuroinflammation, regional β-amyloid deposition, or transient overcompensation during early stages of Alzheimer's disease

Influence of Emotional Content and Context on Memory in Mild Alzheimer's Disease

International audienceHealthy subjects remember emotional stimuli better than neutral, as well as stimuli embedded in an emotional context. This better memory of emotional messages is linked to an amygdalo-hippocampal cooperation taking place in a larger fronto-temporal network particularly sensitive to pathological aging. Amygdala is mainly involved in gist memory of emotional messages. Whether emotional content or context enhances memory in mild Alzheimer's disease (AD) patients is still debated. The aim of the present study is to examine the influence of emotional content and emotional context on the memory in mild AD, and whether this influence is linked to amygdala volume. Fifteen patients affected by mild AD and 15 age-matched controls were submitted to a series of negative, positive, and neutral pictures. Each series was embedded in an emotional or neutral sound context. At the end of each series, participants had to freely recall pictures, and answer questions about each picture. Amygdala volumes were measured on patient 3D-MRI scans. In the present study, emotional content significantly favored memory of gist but not of details in healthy elderly and in AD patients. Patients' amygdala volume was positively correlated to emotional content memory effect, implying a reduced memory benefit from emotional content when amygdala was atrophied. A positive context enhanced memory of pictures in healthy elderly, but not in AD, corroborating early fronto-temporal dysfunction and early working memory limitation in this disease

Impaired Facial Emotion Recognition and Gaze Direction Detection in Mild Alzheimer's Disease: Results from the PACO Study

BACKGROUND: Facial emotion recognition (FER) and gaze direction (GD) identification are core components of social cognition, possibly impaired in many psychiatric or neurological conditions. Regarding Alzheimer's disease (AD), current knowledge is controversial. OBJECTIVE: The aim of this study was to explore FER and GD identification in mild AD compared to healthy controls. METHODS: 180 participants with mild AD drawn from the PACO study and 74 healthy elderly controls were enrolled. Participants were asked to complete three socio-cognitive tasks: face sex identification, recognition of facial emotions (fear, happiness, anger, disgust) expressed at different intensities, and GD discrimination. Multivariate analyses were conducted to compare AD participants and healthy controls. RESULTS: Sex recognition was preserved. GD determination for subtle deviations was impaired in AD. Recognition of prototypically expressed facial emotions was preserved while recognition of degraded facial emotions was impacted in AD participants compared to controls. Use of multivariate analysis suggested significant alteration of low-expressed fear and disgust recognition in the AD group. CONCLUSION: Our results showed emotion recognition and GD identification in patients with early-stage AD compared to elderly controls. These impairments could be the object of specific therapeutic interventions such as social cognition remediation or raising awareness of primary caregivers to improve the quality of life of patients with early AD

Brain Volume Predicts Behavioral and Psychological Symptoms in Alzheimer’s Disease

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