Exploration des mécanismes cognitifs, métacognitifs et autobiographiques dans le déficit d'insight dans la schizophrénie

Dans la schizophrénie, le déficit d insight est d une importance clinique majeure de fait de son lien étroit avec l observance médicamenteuse et l alliance thérapeutique. Ce travail propose au moyen de trois études l exploration du concept d insight, précisant les mécanismes cognitifs sous-tendus et évaluant les effets de 3 nouvelles prises en charge sur son niveau d évolution. Nous nous sommes basés pour cela sur trois modèles théoriques, celui de Conway (2005) qui établit des liens étroits entre le self et la mémoire autobiographique, celui de Larøi et al., (2004) suggérant à l origine du déficit d insight un trouble de la conscience autonoétique en lien avec la mémoire autobiographique, et enfin, celui de Agnew et Morris (1989) incriminant une palette de troubles cognitifs et métacognitifs dans le déficit d insight. Nos résultats soulignent le rôle primordial de la mémoire autobiographique dans le déficit d insight et notamment la qualité des souvenirs sur la période supérieur à >20 ans. De plus les résultats indiquent que, les modèles autobiographique et métacognitif prédisent mieux le déficit d insight comparés au modèle cognitif de base. Parmi les trois programmes thérapeutiques, le programme RECOS (Vianin, 2007), améliore de manière significative le fonctionnement cognitif. Le programme REMAu (Piolino, 2006), visant la reconstruction des souvenirs autobiographique en lien avec le self, améliore de façon significative la conscience du trouble mental et la qualité du rappel épisodique. Le programme MBCT (Segal, Williams et Teasdale, 2002), visant la prise de conscience du moment présent, améliore de façon significative la capacité à attribuer la symptomatologie à la maladie mentale, l estime de soi et la théorie de l esprit. Ces résultats nous amènent à proposer un modèle explicatif et multidimensionnel du déficit d insight dans la schizophrénie, intégrant les trois modèles étudiés ; cognitif, métacognitif et autobiographique.The origins of poor insight in schizophrenia are still unclear. We contrasted the changes in clinical insight, basic cognitive processes, autobiographical memory and metacognition in 63 outpatient s with schizophrenia pseudo-randomly assigned to one of three cognitive remediation groups: one targeting basic cognitive processes (RECOS), a second autobiographical memory (REMAu), and a third metacognitive deficits (MBCT). Three dimensions of insight (awareness of: mental illness, benefit of treatment, psychosocial consequences) improved after treatment, regardless of the group. In addition, the REMAu and MBCT showed an improvement on other dimensions of insight (symptomatic awareness and symptomatic attribution, respectively). Poor insight and its improvement after treatment were best predicted by a combination of basic cognitive, autobiographical and metacognitive measures. This study supports a multidimensional conception of insight and recommends the combination of remediation therapies to improve clinical insight in schizophrenia.PARIS5-Bibliotheque electronique (751069902) / SudocSudocFranceF

Episodic Memory Assessment and Remediation in Normal and Pathological Aging Using Virtual Reality: A Mini Review

Life expectancy is constantly increasing in developed countries. Unfortunately, a longer life does not always correspond to a healthier life, as even normal aging is associated with cognitive decline and increased risk factors for neurodegenerative diseases. Episodic memory (EM) is one of the most vulnerable cognitive functions in aging, and its decline is the hallmark of typical Alzheimer’s disease. This memory system is defined as the ability to acquire and recollect personally experienced episodes associated with a specific affective, spatial, and temporal context. However, most of the neuropsychological and experimental tasks currently employed to assess EM consist in learning simple material (e.g., list of words) in highly stereotyped contexts. In the same vein, classical paper-and-pencil or numeric remediation tools have shown their limitations in the transfer of acquired skills to daily life. Virtual reality (VR), thanks to its immersive properties, and the possibility of delivering realistic and complex scenarios, seems a promising tool to address the limitations of the assessment and remediation of EM. Here, we review existing studies employing VR in normal and pathological aging to assess and reeducate EM. Overall, we show that VR has been mainly used via non-immersive systems. Further studies should, therefore, test the impact of different degrees of immersion. Moreover, there is a lack of VR remediation tools specifically targeting EM. We propose that future studies should fill this gap, addressing in particular the adaptivity of VR remediation protocols

Virtual enactment effect on memory in young and aged populations: a systematic review

Background: Spatial cognition is a critical aspect of episodic memory, as it provides the scaffold for events and enables successful retrieval. Virtual enactment (sensorimotor and cognitive interaction) by means of input devices within virtual environments provides an excellent opportunity to enhance encoding and to support memory retrieval with useful traces in the brain compared to passive observation. Methods: We conducted a systematic review with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines concerning the virtual enactment effect on spatial and episodic memory in young and aged populations. We aim at giving guidelines for virtual enactment studies, especially in the context of aging, where spatial and episodic memory decline. Results: Our findings reveal a positive effect on spatial and episodic memory in the young population and promising outcomes in aging. Several cognitive factors (e.g., executive function, decision-making, and visual components) mediate memory performances. Findings should be taken into account for future interventions in aging. Conclusions: The present review sheds light on the key role of the sensorimotor and cognitive systems for memory rehabilitation by means of a more ecological tool such as virtual reality and stresses the importance of the body for cognition, endorsing the view of an embodied mind

Young and Older Adults Benefit From Sleep, but Not From Active Wakefulness for Memory Consolidation of What-Where-When Naturalistic Events

An extensive psychological literature shows that sleep actively promotes human episodic memory (EM) consolidation in younger adults. However, evidence for the benefit of sleep for EM consolidation in aging is still elusive. In addition, most of the previous studies used EM assessments that are very different from everyday life conditions and are far from considering all the hallmarks of this memory system. In this study, the effect of an extended period of sleep was compared to the effect of an extended period of active wakefulness on the EM consolidation of naturalistic events, using a novel (What-Where-When) EM task, rich in perceptual details and spatio-temporal context, presented in a virtual environment. We investigated the long-term What-Where-When and Details binding performances of young and elderly people before and after an interval of sleep or active wakefulness. Although we found a noticeable age-related decline in EM, both age groups benefited from sleep, but not from active wakefulness. In younger adults, only the period of sleep significantly enhanced the capacity to associate different components of EM (binding performance) and more specifically the free recall of what-when information. Interestingly, in the elderly, sleep significantly enhanced not only the recall of factual elements but also associated details and contextual information as well as the amount of high feature binding (i.e., What-Where-When and Details). Thus, this study evidences the benefit of sleep, and the detrimental effect of active wakefulness, on long-term feature binding, which is one of the core characteristics of EM, and its effectiveness in normal aging. However, further research should investigate whether this benefit is specific to sleep or more generally results from the effect of a post-learning period of reduced interference, which could also concern quiet wakefulness

The Integration of Realistic Episodic Memories Relies on Different Working Memory Processes: Evidence from Virtual Navigation

Memory is one of the most important cognitive functions in a person’s life as it is essential for recalling personal memories and performing many everyday tasks. Although a huge number of studies have been conducted in the field, only a few of them investigated memory in realistic situations, due to methodological issues. The various tools that have been developed using virtual environments (VEs) have gained popularity in cognitive psychology and neuropsychology because they enable to create naturalistic and controlled situations, and are thus particularly adapted to the study of episodic memory (EM), for which an ecological evaluation is of prime importance. EM is the conscious recollection of personal events combined with their phenomenological and spatiotemporal encoding contexts. Using an original paradigm in a VE, the objective of the present study was to characterize the construction of episodic memories. While the concept of working memory has become central in the understanding of a wide range of cognitive functions, its role in the integration of episodic memories has seldom been assessed in an ecological context. This experiment aimed at filling this gap by studying how EM is affected by concurrent tasks requiring working memory resources in a realistic situation. Participants navigated in a virtual town and had to memorize as many elements in their spatiotemporal context as they could. During learning, participants had either to perform a concurrent task meant to prevent maintenance through the phonological loop, or a task aimed at preventing maintenance through the visuospatial sketchpad, or no concurrent task. EM was assessed in a recall test performed after learning through various scores measuring the what, where and when of the memories. Results showed that, compared to the control condition with no concurrent task, the prevention of maintenance through the phonological loop had a deleterious impact only on the encoding of central elements. By contrast, the prevention of visuo-spatial maintenance interfered both with the encoding of the temporal context and with the binding. These results suggest that the integration of realistic episodic memories relies on different working memory processes that depend on the nature of the traces

Mémoire Autobiographique Episodique et Sémantique dans le Vieillissement Normal et dans la maladie d'Alzheimer (Etudes Comportementale et en IRM fonctionnelle)

Au cours de cette thèse, nous nous sommes intéressés au fonctionnement de la mémoire autobiographique, permettant de rappeler nos souvenirs personnels. L autobiographie d une personne fonde son identité et comporte, outre les souvenirs personnels d événements singuliers, phénoménologiquement riches et détaillés (souvenirs épisodiques), des connaissances personnelles détachées de tout contexte particulier. Cette dernière composante stocke un ensemble de connaissances très abstraites sur soi et des souvenirs d événements généraux répétés ou étendus (souvenirs et connaissances sémantisés), issus de sources d encodage multiples et sans accès spontané à un contexte d encodage particulier. L effet de l âge sur ces différents types de matériels autobiographiques fait l objet d études récentes qui ont permis de montrer que les difficultés des sujets âgés sains portent principalement sur les souvenirs épisodiques dont la restitution nécessite une recherche active en mémoire, préservant les souvenirs sémantisés et quelques souvenirs épisodiques, le tout maintenant un sentiment d identité et de continuité dans le temps. Une autre spécificité du vieillissement cognitif réside dans la nécessité de faire face à certains changements liés à l identité qui peuvent être déstabilisant, pendant la vieillesse. Dans ce cadre, les souvenirs personnels constituent le matériel brut grâce auquel notre identité peut graduellement se modifier aux grés des différentes étapes de la vie. Le but de ce travail était de spécifier les processus sous-tendant ces modifications liées au vieillissement. Dans ce cadre, nous avons tenté de mieux comprendre la distinction épisodique/sémantique en mémoire autobiographique et le lien entre cette mémoire et le concept d identité dans le vieillissement normal et dans la maladie d Alzheimer par le biais du concept de souvenirs définissant le Soi. Nous avons également mené une méta-analyse nous permettant de préciser au niveau neural le processus d abstraction des souvenirs et de différencier les substrats cérébraux correspondant à la récupération de matériels autobiographiques, mais aussi à la récupération d informations plus élaborées liées directement à l identité (jugements personnels liés aux traits de personnalités). Pour terminer, nous présentons des résultats permettant de déterminer les modifications cérébrales liées au vieillissement lors de la récupération de souvenirs autobiographiques épisodiques et sémantisés. L ensemble de ces résultats nous a permis de proposer de nouvelles pistes de recherche concernant les causes du déclin cognitif associé à la mémoire autobiographique dans le vieillissement, notamment en termes de lien entre mémoire autobiographique et Soi mais également par rapport au rôle des fonctions exécutives et de leurs substrats cérébraux lors du processus de récupérationIn this work, we investigated the functioning of autobiographical memory which enables the recall of personal past. Autobiographical memory provides the raw material from which identity is constructed and encompasses various types of knowledge from the general knowledge (i.e., semantic component) of a person s past comprising abstracted personal information as well as repeated and extended events to very specific personal events (i.e., episodic component) situated in a particular time and space, for which the subject can mentally travel back through subjective time, reliving the encoding context. Several behavioral studies could show that episodic (which necessitate an active research) but not semantic retrieval become less easy to access in aging. Based on their capacity to retrieve semantic memories and some episodic memories, older people ensure a sense of identity and continuity in time. AM contributes to different aspects of identity and the access to personal memories enable the gradual changes of identity throughout lifespan and aging is a particular phase of change. The aim of this work was to investigate the processes underlying cognitive changes in aging. In this framework, we tried to understand more precisely the link between memory retrieval and the Self in normal aging and Alzheimer s disease studying the Self-defining memories. We also conducted a meta-analysis determining the neural substrates of autobiographical episodic memories, autobiographical semantic memories and self-trait judgments. Finally, we propose fMRI results concerning aging effects on the neural substrates of episodic and semantic autobiographical memory retrieval. Taken together, these results set us on several causes of cognitive decline with aging in the context of autobiographical retrieval; in particular concerning the link between autobiographical memory and the Self and also concerning the role of executive functions during autobiographical retrievalPARIS5-Bibliotheque electronique (751069902) / SudocSudocFranceF

Impaired capacity for prospection in the dementias - Theoretical and clinical implications

International audienceProspection, or future thinking, refers to the ability to mentally simulate plausible events at a future point in time and draws heavily upon the capacity to retrieve autobiographical details from the past. This review examines the extent to which prospection is compromised in neurodegenerative disorders with a view to identifying (1) underlying mechanisms of future thinking disruption and (2) the impact of future thinking deficits on everyday adaptive functioning.MethodsPubMed and MEDLINE were searched for peer-reviewed articles published or in press up to 14 October 2014. The key criterion for inclusion was that the primary outcome measure concerned the envisaging of episodic events at a future time point. Search terms of ‘future thinking’, ‘prospection’, and ‘future simulation’ were used in combination with the following terms: ‘dementia’, ‘Mild Cognitive Impairment’, ‘Alzheimer's disease’, ‘semantic dementia’, ‘frontotemporal dementia’, ‘Parkinson's disease’, ‘Motor Neuron disease’, ‘Vascular dementia’, and ‘Dementia with Lewy bodies’ (e.g., ‘future thinking’ AND ‘Alzheimer's disease’). Searches were limited to articles published in English.ResultsA total of nine unique papers were identified in which prospection was the main outcome measure in dementia. Collectively, these studies reveal marked impairments in the ability to simulate personally relevant events at a future time point in dementia syndromes.ConclusionsFuture research investigating the real-world implications of prospection deficits in dementia is crucial to elucidate the interplay between future-oriented thought and everyday adaptive functions such as prospective memory, decision-making, and maintaining a coherent sense of self over time.Practitioner pointsMarked deficits in future thinking are present in neurodegenerative disorders.Prospection disruption relates to changes in episodic and semantic memory, and executive function.Future studies elucidating the precise mechanisms mediating prospection deficits in dementia are warranted.The potential relationship between future thinking deficits and functional impairment in dementia remains unexplored

LES COMPOSANTES EPISODIQUE ET SEMANTIQUE DE LA MEMOIRE DU PASSE LOINTAIN (ETUDES DANS LE VIEILLISSEMENT NORMAL ET DANS LE SYNDROME AMNESIQUE)

CETTE THESE, CONSACREE A L'ETUDE DE LA MEMOIRE DU PASSE LOINTAIN, EXAMINE LES BASES HISTORIQUES DES TRAVAUX, LES DIFFERENTES COMPOSANTES DE CETTE MEMOIRE ET LES DIVERSES METHODES QUI PERMETTENT DE L'EVALUER EN REFERENCE A LA DICHOTOMIE EPISODIQUE/SEMANTIQUE DE TULVING. L'ACCENT EST PORTE TOUT PARTICULIEREMENT SUR LES MODELES DE LA MEMOIRE AUTOBIOGRAPHIQUE CHEZ L'HOMME NORMAL ET DANS L'AMNESIE. UNQUESTIONNAIRE ORIGINAL PERMETTANT D'EVALUER LES COMPOSANTES EPISODIQUE ET SEMANTIQUE DE LA MEMOIRE AUTOBIOGRAPHIQUE EN FONCTION DE LA DUREE DE L'INTERVALLE DE RETENTION EST PROPOSE DANS UNE PREMIERE ETUDE A UN GROUPE DE 52 SUJETS D'AGE DIFFERENT ET DANS UNE SECONDE ETUDE A UN GROUPE DE 7 PATIENTS PRESENTANT UN SYNDROME AMNESIQUE PERMANENT. NOS RESULTATS MONTRENT QUE LA MEMOIRE EPISODIQUE EST PLUSSENSIBLE AUX EFFETS DE L'AGE, DE L'INTERVALLE DE RETENTION ET DE L'AMNESIE QUE LA MEMOIRE SEMANTIQUE. NEANMOINS, QUELQUES SOUVENIRS EPISODIQUES ANCIENS PERSISTENT DANS LE VIEILLISSEMENT NORMAL ET CERTAINES AMNESIES. LA LOI DE RIBOT SELON LAQUELLE LE PASSE LOINTAIN EST MIEUX PRESERVE QUE LE PASSE RECENT SE VERIFIE DANS LE SYNDROME AMNESIQUE PERMANENT, NOTAMMENT DANS LE SYNDROME DE KORSAKOFF, MAIS PAS DANS LE VIEILLISSEMENT NORMAL. TOUTEFOIS, CE GRADIENT TEMPOREL TRADUIT UNE PRESERVATION DE LA MEMOIRE SEMANTIQUE ET NON DE LA MEMOIRE EPISODIQUE. CES RESULTATS CONFORTENT LA THEORIE DE LA SEMANTISATION SELON LAQUELLE LES SOUVENIRS EPISODIQUES ACQUIERENT AU COURS DU TEMPS ET DES REPETITIONS UNE NATURE SEMANTIQUE MAIS CONTREDISENT LE CARACTERE SYSTEMATIQUE DE CE MODELE. DES ETUDES CORRELATIONNELLES ENTRE LES PERFORMANCES AUTOBIOGRAPHIQUES ET LES PERFORMANCES A DES TESTS NEUROPSYCHOLOGIQUES CLASSIQUES INDIQUENT QUE LES CORRELATIONS DIFFERENT EN FONCTION DE L'INTERVALLE DE RETENTION SUGGERANT UNE REORGANISATION DES PROCESSUS MNESIQUES AU COURS DU TEMPS. CES DONNEES APPORTENT DES ARGUMENTS EN FAVEUR DES MODELES NEUROMIMETIQUES ACTUELS DE LA CONSOLIDATION DE LA TRACE MNESIQUE.CAEN-BU Droit Lettres (141182101) / SudocSudocFranceF

Virtual Reality for Assessment of Episodic Memory in Normal and Pathological Aging

Memory is one of the most important cognitive functions in a person’s life. Memory is essential for recalling personal memories and for performing many everyday tasks, such as reading, playing music, returning home, and planning future actions, and, more generally, memory is crucial for interacting with the world. Determining how humans encode, store, and retrieve memories has a long scientific history, beginning with the classical research by Ebbinghaus in the late 20th century (Ebbinghaus, 1964). Since this seminal work, the large number of papers published in the domain of memory testifies that understanding memory is one of the most important challenges in cognitive neurosciences. With population growth and population aging, understanding memory failures both in the healthy elderly and in neurological and psychiatric conditions is a major societal issue. A substantial body of evidence, mainly from double dissociations observed in neuropsychological patients, has led researchers to consider memory not as a unique entity but as comprising several forms with distinct neuroanatomical substrates (Squire, 2004). With reference to long-term memory, episodic memory may be described as the conscious recollection of personal events combined with their phenomenological and spatiotemporal encoding contexts, such as recollecting one’s wedding day with all the contextual details (Tulving, 2002). Episodic memory is typically opposed to semantic memory, which is viewed as a system dedicated to the storage of facts and general decontextualized knowledge (e.g., Paris is the capital of France), including also the mental lexicon. Episodic memory was initially defined by Tulving as a memory system specialized in storing specific experiences in terms of what happened and where and when it happened (Tulving, 1972). Later, phenomenological processes were associated with the retrieval of memories (Tulving, 2002). Episodic memory is assumed to depend on the self, and involves mental time travel and a sense of reliving the original encoding context that includes autonoetic awareness (i.e., the awareness that this experience happened to oneself, is not happening now, and is part of one’s personal history)

Episodic foresight in normal cognitive and pathological aging

International audienceRésumé. Les recherches de cette dernière décennie témoignent de l’intérêt croissant pourla capacité de l’individu à se projeter dans le futur et à imaginer/prévoir des évènementsdans un futur personnel. Différentes théories ont été proposées pour essayer d’expliquerles mécanismes cognitifs sous-jacents à cette capacité. Dans cet article, nous nous intéressons à la capacité de prospection épisodique dans le vieillissement cognitif normal etpathologique en particulier dans la maladie d’Alzheimer et la démence sémantique. Nousdiscuterons ensuite le rôle des représentations sémantiques personnelles en fonction dela distance temporelle dans la projection épisodique en proposant un nouveau modèle(TEDIFT) qui postule l’intervention de deux processus, la continuité phénoménologiqueou la continuité sémantique en fonction de la distance temporelle de prospection ou derécupération