Brain aging is a heterogeneous phenomenon, and this thesis illustrates how the course of aging can vary within individuals over time and between individuals as a function of age, sex, and genetic variability. We used two contrasts from magnetic resonance imaging (MRI), namely spin-lattice T1-weighted imaging, and quantitative susceptibility mapping (QSM) from gradient-echo images, to picture the aging brain, by means of morphometric measures and brain-iron concentrations. Within each study, the same rigorous imaging acquisitioning protocols were used over large samples sizes of 167-183 individuals, which contribute to the uniqueness of the studies. Most of the current knowledge about the aging brain rests on the foundation of cross-sectional age-related differences, and studies I and III contribute to current knowledge with longitudinal designs to investigate individual rates of change. The importance of genetic variation in relation to regional brain changes was addressed with a specific emphasis on functional polymorphisms involved in pro-inflammatory responses. These studies further shed light on the importance of bi-directional relations between structural integrity and maintained cognitive abilities over time. Study II is the largest study to date to have quantitative susceptibility estimates examined in healthy adults, and the first in-vivo report to show a lowering in overall subcortical brain iron estimates in women from midlife to old age. Studies I and III are unique by examining longitudinal differences in anatomical brain regions using high resolution images from a 4 Tesla scanner. Peripheral vascular risk factors were not strong determinants of either brain- or cognitive changes in the studied samples. The results are discussed in the context of cognitive reserve, the brain maintenance hypothesis, and potential influences of hormones, inflammation and oxidative stress.

Submitted by Leonardo Barcellos (lpbarcellos@gmail.com) on 2017-06-20T00:02:43Z No. of bitstreams: 1 Final version - Dissertation paper - Leonardo Barcellos.pdf: 2615722 bytes, checksum: c5b3c3f34e1c9b8347aec530d34e7f74 (MD5) / Approved for entry into archive by ÁUREA CORRÊA DA FONSECA CORRÊA DA FONSECA (aurea.fonseca@fgv.br) on 2017-06-21T16:00:26Z (GMT) No. of bitstreams: 1 Final version - Dissertation paper - Leonardo Barcellos.pdf: 2615722 bytes, checksum: c5b3c3f34e1c9b8347aec530d34e7f74 (MD5) / Made available in DSpace on 2017-07-05T12:25:37Z (GMT). No. of bitstreams: 1 Final version - Dissertation paper - Leonardo Barcellos.pdf: 2615722 bytes, checksum: c5b3c3f34e1c9b8347aec530d34e7f74 (MD5) Previous issue date: 2017-06-07 / This dissertation paper gathers three studies on the relationship between accounting practice and certified public accountants’ (CPAs) cognitive reflection abilities (CR-ability). The first chapter summarizes the three studies, presenting contextual information about how the research ideas and identification strategies relate to my doctoral studies. The study in the second chapter maps Brazilian CPAs’ CR-abilities to demographic characteristics, providing not only the foundational insights for the studies in the next chapters but also evidence that male and younger CPAs tend to present higher CR-abilities than female and older CPAs, as well as that employer firm size may determine CR-abilities of preparers and managers. The study in the third chapter applies a quasi-experimental approach to examine whether auditing practice is more likely to prevent CR-abilities decline than financial reports elaboration practice. The paper explores the unique counterfactual opportunity provided by the accounting setting to find that aging leads human beings to adapt information processing strategies towards Type 1 of reasoning in detriment of Type 2. But auditing practice may curb this trend. These findings make several contributions to psychology and accounting fields. The paper in the fourth chapter examines the influence of stable CPAs’ individual characteristics, i.e., CR-ability and professional experience in pressured firms, on the professional judgments behind the recognition of assets and cash flows arising from audiovisual content (AV-content). The findings suggest that CR-ability drives differential AV-content assets and cash flows classification at recognition and, ultimately, incomparable financial statements, but professional experience in pressured firms is likely to refrain such differences in the case of assets. Finally, I present my concluding remarks in the fifth chapter.

Evidence for the utility of the Mild Cognitive Impairment (MCI) classification as a predictor of impending dementia in older adults is somewhat limited. Although individuals with MCI show elevated rates of conversion to dementia at the group level, heterogeneity of outcomes is common at the individual level. Using data from a prospective five-year longitudinal investigation of cognitive change in a sample of 262 healthy older adults aged 64 to 92 years, this study was designed to address key limitations in current MCI classification procedures which tend to rely on single occasion assessment (Traditional MCI) by evaluating an alternate operational definition of MCI requiring evidence of persistent cognitive impairment over multiple testing sessions (Persistent MCI), and four subsequent variations of this operational definition. It was hypothesized that: (1) prevalence of Traditional MCI would exceed prevalence of Persistent MCI across all variations in the operational definition, (2a) both the Traditional MCI and Persistent MCI groups would show lower levels of performance and greater decline in both cognitive and functional status over five years relative to Controls, (2b) the magnitude of these differences between those classified as Persistent MCI and Controls would exceed the magnitude of differences between those classified as Traditional MCI and Controls, and (3) the pattern of findings outlined in hypothesis 2 would persist under the four variations of the Traditional MCI and Persistent MCI inclusion criteria. Results were consistent with Hypothesis 1, and partially consistent with Hypotheses 2 and 3. In general, the Persistent MCI groups showed a lower mean baseline level of performance and a steeper trajectory of cognitive decline compared to the Control group and the Traditional MCI groups, although the sample-wide change in cognitive and functional status was small. There was some evidence that the variation of Persistent MCI classification which specified persistent memory impairment as an inclusion criteria achieved optimal prediction of cognitive and functional decline. Results are discussed with reference to retest effects, cognitive reserve, and clinical utility of the Persistent MCI concept for enhancing prediction of dementia in older adults.

No description available.

Depuis plusieurs années, la réalité virtuelle est largement utilisée en neuropsychologie, notamment dans le domaine de l’étude de la cognition spatiale. Son utilisation grandissante a pour but de répondre à la fois au manque de validité écologique des tests classiques et au manque de contrôle des évaluations en conditions réelles. Les études dans le domaine de la cognition spatiale ont permis de montrer la complexité de l’apprentissage et de la navigation dans les grands espaces et suggèrent également une origine cognitive multifactorielle des difficultés de navigation chez les personnes âgées. Le but de cette thèse sera tout d’abord de vérifier la validité écologique de notre application utilisant la réalité virtuelle par une comparaison directe des performances d’apprentissage et de navigation, entre apprentissages réels et virtuels chez des adultes jeunes et âgés. Il s’agira ensuite de confirmer les hypothèses sur l’origine à la fois mnésique et exécutive des difficultés de navigation liées au vieillissement. Enfin, le rôle du contrôle sensorimoteur dans l’apprentissage de grands espaces, peu étudiée pour le moment dans le cas du vieillissement sera abordé. A l’aide d’une application en réalité virtuelle, nécessitant de mémoriser un parcours dans un quartier virtuel, réplique d’un quartier de Bordeaux, nous avons étudiés les effets du vieillissement en termes de mémoire spatiale et de performance de navigation. Nous avons comparé directement les apprentissages en conditions réelles et virtuelles, en conditions actives (joystick) et passives, et nous avons mis en relation ces indicateurs avec des mesures neurocognitives et des questionnaires d’estimation des difficultés quotidiennes. Nos principaux résultats ont permis de montrer un effet négatif de l’âge sur les performances dans notre application avec des patterns équivalents entre apprentissages réels et virtuels chez les jeunes et les âgés. Nous avons obtenu une bonne relation entre les mesures obtenues grâce à notre application virtuelle et les difficultés rapportées par les jeunes mais pas de différences entre jeunes et âgés concernant les difficultés de navigation au quotidien. Ces résultats confirment la bonne validité écologique de notre application virtuelle chez les personnes âgées et favorisent ainsi l’utilisation de mesures directes de mémoire spatiale et de navigation plutôt que des questionnaires chez les personnes âgées. Ils ont également permis de montrer de manière directe le rôle des déclins mnésiques et exécutifs dans leurs difficultés de navigation. Contrairement à ce qui avait été obtenu chez les jeunes, le contrôle moteur a eu un effet négatif sur les performances de navigation chez les personnes âgées. Nous discuterons alors les hypothèses neurocognitives concernant l’origine des difficultés de navigation chez les personnes âgées, ainsi que le rôle de la dimension actif (joystick) vs. passif dans les performances de navigation des jeunes et des âgés. / Since several years, virtual reality is widely used in neuropsychology, especially for the study of spatial cognition. The goal of its use is to respond to the lack of ecological validity of classical tests and to the lack of experimental control of assessments in real situations. The studies in the domain of spatial cognition reveal the complexity of learning and navigation activities in large scales spaces and suggest a multifactorial origin to spatial learning and navigation in older adults. The aim of this thesis will be first to verify the ecological validity of our virtual reality application, with a direct comparison of spatial learning and navigation performances between real and virtual learning conditions, in young and old participants. Another goal will be to confirm the hypothesis on the role of executive and memory decline in age-related spatial learning and navigation difficulties. Finally, the role of motor control in spatial learning in large scale spaces, which is poorly studied within the framework of aging, will be tested. With the use of a virtual reality application, requiring memorizing a path in a virtual district replicating a district of Bordeaux, we have studied the effects of aging on spatial memory and navigation performances. We compared real and virtual, active and passive learning conditions and studied the relation between spatial memory and navigation performances with neurocognitive measures and self-report questionnaires on everyday navigation difficulties. Our main results showed a negative effect of aging on the performances in our application, with pattern of results similar between real and virtual learning conditions in young and old participants. We obtained a good relation between measures from our virtual application and everyday navigation difficulties reported by the young participants but no differences between young and old participants on everyday navigation difficulties. These results confirm the good ecological validity of our virtual application and favor the use of direct navigation and spatial memory measures instead of self-report questionnaires for older adults. They also showed directly the role of memory and executive decline in older adults’ navigation difficulties. Contrary to the results obtained with the young participants, the motor control had a negative effect on navigation performances in older adults. We will discuss of the neurocognitive hypothesis already proposed concerning the origin of navigation difficulties due to aging. Also, the role of motor activities and dual-task effect on spatial navigation performances in older adults will be examined.

A ce jour, nous savons peu de choses sur la manière dont la mémoire épisodique quotidienne, visuellement riche et complexe en termes d’éléments contextuels, est affectée par le vieillissement normal contrairement aux connaissances acquises dans le domaine du vieillissement sur la mémoire épisodique verbale ou visuelle au moyens des tests traditionnels ou des procédures de laboratoire comme le paradigme de rappel libres multi-essais (e.g., utilisé par le California Verbal Learning Test). La présente thèse s’est par conséquent attachée à implémenter ce paradigme traditionnel de rappels libres multi-essais d’évaluation de la mémoire épisodique au sein d’un dispositif RV simulant une visite dans un appartement, le HOMES test (Human Objet Memory of Everyday Scenes test). Cette procédure permet de dériver des indices d’apprentissage, de catégorisation, d’interférence proactive, de bénéfice de la reconnaissance comparée au rappel libre, et de fausses reconnaissances. A cela, nous nous sommes intéressés aux relations entre la mémoire quotidienne et l’action à travers l’effet denavigation active.A l’aide d’études comparatives, nous avons retrouvé le profil mnésique classiquement observé avec le test « papier-crayon », excepté pour l’interférence proactive qui n’est pas observée comme augmentée chez les participants âgés. En effet, des scores de rappel réduits,un bénéfice accru de la reconnaissance, une sensibilité augmentée aux fausses reconnaissances, et des capacités de regroupements sémantiques sont obtenus. Chez les jeunes adultes avec traumatisme crânien (étude 1), un profil identique est observé alors qu’un profil bien différent est obtenu auprès des patients avec maladie Alzheimer (étude 2) avec notamment un tableau associant des déficits plus marqués et des capacités de catégorisation altérées. Les études 3 et 4 adressant l’effet de navigation active chez le sujet jeune et âgé, ont mis en évidence un effet bénéfique de la navigation active sur la reconnaissance chez les deux groupes de sujets. Par contre, la navigation active diminuait les fausses reconnaissances des jeunes mais augmentait celles des âgés. Nous discutons les résultats de ces études sur la mémoire quotidienne à travers les hypothèses de déficit-item spécifique et du déclin fronto-exécutif du vieillissement normal. / To this day, very little is known about the way aging affects everyday episodic memory, which is a visually and contextually rich and complex memory. However, episodic memory is traditionally assessed using verbal tasks which are lacking such complexity. One of them, the California Verbal Learning Test (CVLT) uses the multi-trial free recall paradigm that we also implemented in the Human Object Memory of Everyday Scenes test using virtual reality to simulate a visit in an apartment (the HOMES test).This procedure allowed us to assess multiple memory processes such as learning, semantic clustering, proactive interference, recall versus recognition, and false recognitions. We also wanted to investigate the relationship between everyday memory and action through active navigation and its effects on each of these processes. We showed the typical profile of older adults usually obsereved using traditional paper-pencil tests on most of the memory indices except for proactive interference, which was not increased. In fact, older adults showed a reduced free recall performance despite a preserved learning ability across trials, a benefit from recognition but also a higher susceptibility to false recognitions. TBI patients (study 1) showed a profile similar to that of older adults, but patients with Alzheimer disease were impaired on all of the HOMES indices (study 2). Studies 3 and 4 examined the beneficial effect of active navigation in younger and older adults’ everyday memory and showed that that recognition was the measure that benefited the most in both age groups. In contrast, older adults while active navigation decreased false recognitions in younger adults, it actually increased false recognitions in older adults. Our results on everyday memory are discussed in terms of item-specific deficit and executive deficit hypotheses in normal aging.

Diversos estudos de ressonância magnética (RM) em idosos saudáveis tem avaliado a relação entre envelhecimento, diminuições volumétricas de substância cinzenta (SC) e desempenho cognitivo, usando desenhos de corte transversal e testes de correlação. No entanto, poucos estudos de volumetria baseada em voxel (VBM) tem relatado a diminuição de SC em idosos saudáveis com medições repetidas de RM nos mesmos indivíduos, e nenhum desses estudos longitudinais investigaram a relação entre as mudanças de SC e desempenho cognitivo ao longo do tempo. Além disso, não está claro em achados longitudinais qual a extensão da influência do APOE?4 sobre as reduções de SC em idosos saudáveis. Foram inicialmente avaliados 187 sujeitos idosos (acima de 65 anos) da comunidade, e após 3 anos, uma subamostra de 55 sujeitos realizaram um segundo exame de RM estrutural em equipamento de 1,5 Tesla, bem como reavaliação cognitiva com instrumentos padronizados e validados transculturalmente. Todos os sujeitos foram genotipados para determinar a presença/ausência do alelo APOEe4, bem como a avaliação clínica do grau do risco cardiovascular de acordo com escores de Framingham (FRS). Usando a técnica de VBM, testamos as hipóteses de que: a progressão da perda do desempenho cognitivo está associada a diminuições volumétricas de SC ao longo de 3 anos, envolvendo a região hipocampal e os neocórtices temporal e frontal; e perdas cognitivas associadas à diminuição progressiva de SC cerebral serão maiores em indivíduos com alto risco cardiovascular e em portadores de alelo da APOEe4. Foram encontradas reduções globais e regionais de SC no tálamo direito e giro parahipocampal esquerdo (p < 0,05, family-wise error corrigido para comparações múltiplas por todo o cérebro). Estes resultados não foram afetados pela influência da APOEe4. Foi detectada uma tendência (p=0,093) na correlação entre o grau de declínio cognitivo e redução volumétrica no tálamo direito. Este resultado se manteve quando um coeficiente parcial de correlação foi calculado levando em conta as variações nos escores FRS. Independentemente da APOEe4, as análises longitudinais de VBM mostraram que a região do hipocampo e tálamo são áreas críticas onde a redução de SC e maior que a redução volumétrica global em idosos saudáveis. Os resultados da associação entre a redução de SC no tálamo e a mudança no desempenho cognitivo ao longo do tempo, apoia o recente reconhecimento do papel do tálamo no declínio cognitivo sutil associado ao envelhecimento saudável / A number of magnetic resonance imaging (MRI) studies have investigated the relationship between aging, reduced gray matter (GM) volumes in the brain and cognitive performance, using cross-sectional designs and correlation tests. However, very few VBM studies have documented GM decrements in healthy elderlies with repeated MRI measurements obtained in the same subjects, and none of these longitudinal studies investigated the relationship between GM deficits and changes in cognitive performance over time. Also, it is unclear the extent to which the APOE e4 allele influences on longitudinal findings of GM reductions in healthy elderlies. Were initially evaluated 187 elderly subjects (over 65 years); after 3 years, a sub-sample of 55 individuals underwent a second MRI examination in a 1.5 Tesla equipment, and a cognitive re-evaluation using a structured, transculturally validated neuropsychological battery. All subjects also underwent genotyping for ascertainment of the presence of the APOEe4 allele, as well as clinical assessment of cardiovascular risk according with Framingham scores (FRS). Using voxel-based morphometry (VBM), we will test the following hypotheses: the progression of cognitive decline will be associated with volumetric reductions of GM over three years, involving the hippocampal region and the temporal and frontal neocortices; cognitive decline associated with progressive GM volume reductions will be greater in individuals with higher cardiovascular risk and carriers of the APOE?4 allele. We found global GM reductions as well as regional GM decrements that were significant in the right thalamus and left parahippocampal gyrus (p < 0.05, family-wise error corrected for multiple comparisons over the whole brain). These findings were not affected by APOE e4. A trend correlation (p=0.093) was detected between the degree of cognitive decline over time and right thalamic volume shrinkage. This finding retained statistical significance when a partial coefficient of correlation was calculated taking into account variations in FRS scores. Irrespective of APOEe4, longitudinal VBM analyses show that the hippocampal region and thalamus are critical sites where GM shrinkage is significantly greater than the degree of global brain volume reduction in healthy elders. The trend towards an association between thalamic GM decrement and cognitive performance change over time supports the recently recognized role of the thalamus in the subtle cognitive decline associated with healthy human aging

Au travers des données cognitives de la cohorte stéphanoise PROOF, l’objectif de ce travail de thèse a été de déterminer quelle pouvait être la valeur pronostique de plusieurs facteurs, entre autres psychosociaux et physiologiques, d’un maintien optimal du fonctionnement cognitif avec l’âge.Le premier axe de recherche de ce travail, a mis en évidence que 70% des 632 participants âgés de 67 ans à la première évaluation cognitive de l’étude PROOF, présentaient une stabilité de leur fonctionnement cognitif après 8 ans de suivi. Le principal facteur mis en cause dans le vieillissement cognitif de cette population, que nous avons qualifié de « réussi », était, pour ces participants, d’avoir un haut niveau d’implication dans des activités sociales.Le second axe de recherche de ce travail, a mis en évidence que la dégradation de la régulation autonomique, et non la présence de facteurs de risque cardiovasculaires classiques, avait un impact négatif sur le fonctionnement mnésique des participants. Confortant ces résultats, nous avons montré que les pathologies respiratoires liées au sommeil avaient un impact négatif sur le vieillissement cognitif normal, avec un impact délétère de la fragmentation autonomique nocturne sur l’évolution des capacités mnésiques. Une préservation de l’activité du Système Nerveux Autonome (SNA) pourrait donc être une clé d’un maintien optimal des capacités mnésiques au cours du vieillissement normal.Le troisième axe de recherche de ce travail, a mis en évidence que les plaintes, qu’elles soient cognitives ou liées à la qualité de sommeil, étaient stables au décours du vieillissement normal. Nous avons pu démontrer que ce n’est pas l’âge qui génère la plainte, mais la qualité de vie et l’état anxiodépressif des personnes qui les expriment. Ceci n’est pas sans nous rappeler que le sujet, son symptôme et son histoire sont autant de déterminants du vieillissement cognitif « réussi ». Le quatrième axe de recherche de ce travail, a enfin mis en exergue que la prise en compte de la richesse des interactions sociales menées tout au long de la vie était un élément déterminant du niveau de performances dans des tâches de cognition sociale de personnes agées de 78 ans, et ce, indépendamment de la nature du fonctionnement exécutif et du niveau socioculturel. En conclusion, le vieillissement cognitif « réussi » n’est pas uniquement une vision optimiste du bien vieillir, allant contre des stéréotypes négatifs sur une perte systématique des fonctions cognitives liée à l’âge. Il s’agit d’un concept multidimensionnel qu’il convient de bien cerner si l’on veut mettre en place des stratégies efficaces susceptibles d’intervenir sur le maintien des capacités cognitives avec l’âge. Ce travail de thèse a permis de mettre en évidence l’identification de quatre facteurs déterminant du vieillissement cognitif « réussi » (et pour lesquels une intervention est possible !) qui sont : 1) le maintien des activités sociales tout au long de sa vie ; 2) la préservation d’un bon équilibre du système sympathique-parasympathique ; 3) l’absence de pathologies respiratoires liés au sommeil ; 4) la stabilité des plaintes (sommeil, cognition) exprimées avec l’âge. / The aim of this thesis was to examine cognitive performances of a large French cohort study of elderlies, i.e. the Saint Etienne PROOF-Siempre cohort, in order to assess among several factors which of them could play a prognostic role on a successful cognitive aging including physiological and psychosocial factors. In order to assess these key factors we developped several research axes frequently examining the long-term changes.The first axis of the research consider the overtime evolution of cognitive function in this population. We found that 70% of the 632 participants 67 yrs old at their inclusion in the study with or without sleep related breathing disorders had stable cognitive data 8-yr later. In this sample that we defined as having a successful cognitive aging, the predictive factor was the "high level of social activities" without any contribution of the demographic data, the hypoxemic load or classical vascular and metabolic factors.The second axis of the research we examined the influence of the autonomic nervous system activity of cognitive performances. In a sample of 916 older people, we found that a parameter reflecting the parasympathetic arm of the ANS, the baroreceptor sensitivity, affect when it was found altered the memory function without interference of other cardiovascular risk factor. These results were confirmed in a 8-yr assessment on 425 subjects of the previous sample in whom again a alteration of baroreceptor sensitity affect the long-term changes on memory function with contribution of the other examined factors. This would suggest that autonomic nervous system may also influence the memory changes with aging and assuring a more successful cognitive aging.The third axis of the research was to define how subjective cognitive and sleep complaints remain stable across time and whether subjective estimation of sleep quality may affect the changes on the subjective cognitive complaints. We found again a stability of the subjective cognitive complaint without any interference of sleep quality and aging itself, the quality of life and the presence of anxiety and depression being the most important factors. The four axis of the research examined the possible effect of the degree of social interaction developed along lifetime on the social cognition. We found in group of 100 elderly aged 78 yrs that quality of social interactions in the life-span was the key factor implicated in late social cognitive skills in the elderly without any effect of the executive function status nor the educational and intellectual level.In conclusion, we have demonstrated that in contrast to the most common recognized of a systematic loss of cognitive functions related to age healthy elderlies may have a successful cognitive aging. The "successful" cognitive aging is a multidimensional concept that should clearly identify if one wants to adopt effective strategies to maintain cognitive abilities with age. The different aspects examined in this thesis have highlighted the identification of four determinants of a "successful" cognitive aging: 1) the maintenance of social activities throughout the life; 2) the preservation of a sympathetic-parasympathetic balance of the autonomic nervous system; 3) the lack of sleep-disordered breathing; and 4) the stability of sleep and cognitive complaints generally reported in older population. The application of those strategies may help to prevent the cognitive decline in older populations.

Depuis de nombreuses années, la littérature s’attache à mettre en évidence que, malgré les déficits cognitifs liés à l’avancée en âge, chaque individu peut bénéficier de ses expériences afin de les réinvestir quotidiennement à travers une optimisation de ses comportements, via le maintien d’un certain niveau de plasticité cognitive (i.e., théorie de l’enrichissement cognitif). Dans cette perspective, ce travail vise à appréhender l’étendue de la plasticité comportementale des seniors via l’étude du transfert d’apprentissage issu des exergames. Son ambition est d’établir quels peuvent être les bienfaits de la pratique des exergames afin de lutter contre les effets délétères du vieillissement cognitif normal. Il s’agit, au travers de deux études d’entrainement, d’identifier le potentiel de transférabilité de nouvelles acquisitions cognitives et motrices via cet outil d’entrainement virtuel. La première étude a mis en évidence qu’un programme d’entrainement en exergames de trois mois permet l’amélioration des fonctions exécutives et de la vitesse de traitement de l’information chez des personnes âgées sédentaires. Ces résultats suggèrent que ces améliorations cognitives pourraient prendre leurs sources explicatives, d’une part, via la sollicitation physique se traduisant ici par des améliorations physiques notamment au niveau de l’endurance cardiorespiratoire, et d’autre part, via l’intermédiaire de la stimulation cognitive induite par le jeu qui, grâce à la diversité des tâches et des interactions, a engendré un transfert vers les tests neuropsychologiques. La seconde étude a pour objectif d’identifier l’occurrence d’un transfert virtuel-réel au travers d’un contexte de similarité entre les éléments constituant nos deux tâches expérimentales, à partir d’une tâche de putting au golf. La comparaison de performances des deux groupes d’âges entrainés selon deux contextes d’apprentissage (réel versus virtuel) a mis en évidence que les adultes jeunes étaient parvenus à réinvestir les habiletés acquises issues du virtuel dans le contexte réel, à la différence des adultes âgés qui, bien qu’ils aient atteint une réelle acquisition motrice en contexte virtuel, n’ont pas réussi à réengager de façon optimale leur acquisition antérieure. Ce travail doctoral atteste que les exergames peuvent, à travers une stimulation à la fois physique et cognitive, être un moyen efficace de lutter contre les effets délétères liés à l’avancée en âge. / For years, research literature has underlined that, notwithstanding the cognitive deficits related to advancing age, individuals may continue to benefit from their prior experiences in the optimization of their behavior, aided by the maintenance of a certain level of cognitive plasticity (i.e., concept of enrichment effects). The present research aims to understand the extent of seniors’ behavioral plasticity and establish how exergames may assist them in countering the deleterious effects of normal cognitive aging. This research consists of two studies which aim to identify the potential for cognitive and motor acquisitions via the use of virtual training devices. The first study highlights that a three month exergame training program improved both executive functions and the speed of processing in sedentary seniors. These results suggest that such cognitive improvements may be explained by (1) physical solicitation resulting in improved cardiorespiratory endurance, and (2) by the game-related cognitive stimulation (due to the variety of tasks and interactions) further transferring to neuropsychological tests. The second study is designed to identify the occurrence of a virtual-real transfer through context similarity between our two experimental tasks, both based on a golf-putting task. Compared performances between the two age groups, having trained in one of two learning conditions (real versus virtual) underlined that young adults were able to reinvest the acquired skills from the virtual to the real context, in contrast to older adults. Even though the latter acquired actual motor skills in virtual context, they failed to optimally re-engage prior acquisitions. This doctoral research attests that exergames, through both physical and cognitive stimulation, may be an effective means to counter the deleterious effects related to advancing age.

Das dominante Datenmuster im Bereich des kognitiven Alterns ist der Alters-x-Komplexitätseffekt. Die vorliegende Studie untersucht, ob das Muster statt durch einen üblicherweise postulierten unspezifischen durch einen spezifischen Mechanismus erklärt werden kann: die mit dem Alter abnehmende Reliabilität episodischer Akkumulatoren. In sechs Reaktionszeit-Experimenten wurden junge und ältere Erwachsene verglichen, dabei wurden frühe kognitive (Stroop-Bedingung) und episodische Schwierigkeit (Reiz-Reaktions-Zuordnung) orthogonal manipuliert. Die vorhergesagte Dreifachinteraktion der beiden Faktoren mit dem Alter zeigte sich über die Experimente hinweg relativ konsistent. Eine modifizierte Brinley-Analyse ergibt deutlich unterschiedliche Steigungen der Regressionsgeraden im Alt-Jung-Raum für niedrige und hohe episodische Schwierigkeit. Als methodischer Beitrag wird im Anhang ein zur modifizierten Brinley-Analyse passendes Regressionsmodell entwickelt, das aus einigen einfachen Verarbeitungsannahmen folgt. Es wird gezeigt, dass in einer klassischen Brinley Metaanalyse die Steigung neben der theoretisch interessierenden Varianz von theoretisch uninteressanter Zwischen-Experiment-Varianz beeinflusst wird. / The age-by-complexity effect is the dominant empirical pattern in cognitive aging. The current report investigates whether a specific high-level mechanism---an age-related decrease in the reliability of episodic accumulators---can account for the age-by-complexity-effect, which is commonly assumed to be caused by an unspecific, low-level deficit. Groups of younger and older adults are compared in six reaction time experiments, using orthogonal manipulations of early cognitive difficulty (e.g., Stroop condition) and episodic demands (e.g., stimulus-response mapping). The predicted three-way interaction of age and the two factors was observed fairly consistently across experiments. A modified Brinley analysis shows that different regression slopes in old-young-space are required for conditions with low and high episodic difficulty. As a methodological contribution, a Brinley regression model following from certain simple processing assumptions is developed. It is shown that in contrast to a standard Brinley meta-analysis, the regression slopes in this model are not influenced by theoretically un-interesting between-experiment variance.