La plasticité cérébrale donne l’opportunité à chaque individu de maximiser son fonctionnement cognitif via l’adoption de comportements enrichis (i.e., théorie de l’enrichissement cognitif). Suivant cette perspective, nous avons articulé dans le cadre de ce travail doctoral des hypothèses inhérentes au rôle modérateur du style de vie sur le déclin cognitif tout au long de la vie adulte, et avons observé le rôle du sexe dans cette relation. La contribution scientifique de ce travail se manifeste au travers de la création et la validation d’un outil de mesure du style de vie (étude 2), et de deux études observationnelles portant (i) sur l’activité physique (étude 1) et (ii) sur le style de vie global (étude 3). Les résultats de cette thèse mettent en évidence l’existence de différents patterns influant sur le vieillissement cognitif, ainsi qu’un important rôle modérateur du sexe dans la relation entre style de vie et déclin cognitif lié à l’âge. Plus précisément, les résultats montrent que le style de vie global, ainsi que les dimensions incluant les relations sociales, les activités physiques pratiquées à long terme et les autres activités de loisirs, sont efficaces pour freiner le vieillissement cognitif chez les femmes uniquement. Si les sollicitations cognitives ne permettent pas, quant à elles, de ralentir la courbe du déclin cognitif, elles influencent de manière positive les performances cognitives tant chez les femmes que chez les hommes. Ce travail doctoral atteste que le style de vie peut représenter un moyen efficace pour lutter contre les effets délétères liés à l’avancée en âge, et permettre non seulement d’ajouter des années à la vie, mais aussi de la vie aux années. / Cerebral plasticity provides an opportunity for each individual to maximize his/her cognitive performance through the adoption of enriched behaviors (i.e., Cognitive Enrichment Theory). From this perspective, we had articulated work hypotheses inherent to the moderating role of lifestyle on the age-related cognitive decline throughout adult lifespan, and we observed the role of sex in this relationship. The scientific contribution of this work occurred through the creation and validation of a lifestyle questionnaire (study 2) and two observational studies about (i) physical activity (study 1) and (ii) the general lifestyle (study 3). Results of this thesis showed the existence of different models influencing cognitive aging, as well as an important moderating role of sex in the relationship between lifestyle and age-related cognitive decline. More specifically, results highlighted that general lifestyle, as well as dimensions including social relationships, long-term physical activities and other leisure activities, were effective for cognitive aging in women only. While cognitive solicitations did not show to slow down the cognitive decline, they had a positive influence on cognitive performances in both women and men. This PhD demonstrated that lifestyle can be an effective way to combat the deleterious effects of aging and could not only add years to life, but also add life to years.

This systematic review aims to investigate the effects of aerobic exercise on the neuroal basis of memory functions in healthy elderly individuals. The search was conducted in accordance with PRISMA and covered three electronic databases, namely PubMed, Scopus, and Web of Science, for peer-reviewed published, and original research. Six studies met the inclusion criteria and were included in the review. The studies utilized various behavioral or cognitive tasks related to memory, including the Sternberg Working Memory Task, Spatial Memory tests, and neuroimaging techniques such as magnetic resonance imaging (MRI). This systematic review suggests that aerobic exercise can improve memory in healthy elderly individuals, including spatial, working, and short- and long-term memory. As revealed by neuroimaging techniques, memory function improvement was accompanied by changes in brain structure and function in memory-processing regions. These findings provide evidence that aerobic exercise can improve the neurological basis of memory function in healthy elderly individuals. The beneficial effects of aerobic exercise on memory have significant implications for the aged population. Memory loss is a common and often debilitating issue in older adults, and the ability to recall and learn new information is crucial for maintaining independence and quality of life. Therefore, aerobic exercise is a promising intervention to improve memory function in healthy elderly individuals.

The number of older adults is estimated to double from 52 million to 95 million by 2060. Approximately 80-85% of older adults are diagnosed with a chronic health condition. Many of these chronic health conditions are influenced by diet and exercise, suggesting improved diet and eating behaviors could improve health-related outcomes. One factor that might improve dietary habits in older adults is food-related inhibitory control. We tested whether food-related inhibitory control, using behavioral (response time, error rate) and scalp-recorded event-related potential (ERP; N2 and P3 components) measures of food-related inhibitory control differed between younger and older adults over age 55. Fifty-nine older adults (31 females [52.5%], Mage=64, SDage=7.5) and 114 younger adults (82 females [71.9%], Mage=20.8) completed two go/no-go tasks, one inhibiting to high-calorie stimuli and one inhibiting to low-calorie stimuli, while electroencephalogram (EEG) data were recorded. Older adults had slower overall response times than younger adults, but this was not specific to either food task. There was not a significant difference for accuracy between younger and older adults, but both groups' accuracy and response times were significantly improved during the high-calorie task than the low-calorie task. For both the N2 and P3 ERP components, younger adults had greater amplitude than older adults, but this effect was not food-specific, reflecting overall generalized lower inhibitory processing in older adults. Of note, P3 amplitude for the younger adults demonstrated a specific food-related effect (greater P3 amplitude for high-calorie no-go) that was not present for older adults. Findings support previous research demonstrating age related differences in inhibitory control though those differences may not be specific to inhibiting to high-calorie foods.

Yes / Objective: We conducted a U.K.-wide survey to collect information on people's beliefs, fears, perceptions, and attitudes to cognitive aging. Methods: This community-based aging survey included 3,146 adults aged 40 years and over. Results: Respondents believed memory might be the earliest cognitive skill to decline (mean: 59.4 years), followed by speed of thinking (mean: 64.9). Those in their 40s were more pessimistic, because they estimated cognitive changes would start up to 15 years earlier than respondents aged over 70. Having a purpose in life, healthy eating, challenging the mind, sleep, and physical activity ranked higher in terms of perceived importance for maintaining or improving cognitive skills. However, less than 50% engaged in any of these activities. Although 91% believed there are things people can do to maintain or improve their cognitive skills, more than 40% were unsure or did not know how to do so. Respondents who strongly agreed that changes in cognitive skills might be a sign of something more serious were significantly more likely to do various activities to benefit their cognitive skills. Conclusion: Results suggest that people are less aware of the potential cognitive benefits of certain activities, such as exercise and diet. It is important to build awareness about the benefits of lifestyles and activities for cognitive health. / Velux Stiftung (Project No. 1034).

Yes / Purpose: Listening-related fatigue is a potential negative consequence of challenges experienced during everyday listening, and may disproportionately affect older adults. Contrary to expectation, we recently found that increased reports of listening-related fatigue were associated with better performance on a dichotic listening task (McGarrigle et al., 2021a). However, this link was found only in individuals who reported heightened sensitivity to a variety of physical, social, and emotional stimuli (i.e., increased ‘sensory-processing sensitivity’; SPS). The current study examined whether perceived effort may underlie the link between performance and fatigue. Methods: 206 young adults, aged 18-30 years (Experiment 1) and 122 older adults, aged 60-80 years (Experiment 2) performed a dichotic listening task and were administered a series of questionnaires including: the NASA task load index of perceived effort, the Vanderbilt Fatigue Scale (measuring daily life listening-related fatigue) and the Highly Sensitive Person Scale (measuring SPS). Both experiments were completed online. Results: SPS predicted listening-related fatigue but perceived effort during the listening task was not associated with SPS or listening-related fatigue in either age group. We were also unable to replicate the interaction between dichotic listening performance and SPS in either group. Exploratory analyses revealed contrasting effects of age; older adults found the dichotic listening task more effortful, but indicated lower overall fatigue. Conclusions: These findings suggest that SPS is a better predictor of listening-related fatigue than performance or effort ratings on a dichotic listening task. SPS may be an important factor in determining an individual’s likelihood of experiencing listening-related fatigue irrespective of hearing or cognitive ability. / This research was supported by an ESRC New Investigator Award (ES/R003572/1) to Ronan McGarrigle.

Avec l’avancée en âge, l’efficience de l’ensemble des fonctions cognitives, en particulier la mémoire épisodique, tend à diminuer. L’étude des effets Dm et old/new et des résultats de la méthode sLORETA a permis de caractériser sur un plan neurofonctionnel deux types de vieillissement non pathologique chez les seniors. D’une part, le vieillissement cognitif stable se traduit par des processus d’encodage identiques à ceux observés chez des sujets jeunes alors que les processus de récupération nécessitent un recrutement bilatéral des lobes temporaux médians, cette activation étant unilatérale chez les sujets jeunes. Ces résultats vont dans le sens du modèle HAROLD qui suggère une réduction de l’asymétrie hémisphérique avec l’âge. D’autre part, le vieillissement cognitif altéré proviendrait d’une altération des réseaux cérébraux dès la phase d’encodage. La baisse d'activité au niveau du cortex préfrontal gauche, siège des fonctions exécutives, suggèrerait une difficulté de mise en œuvre de stratégies d'encodage efficaces et aurait un impact direct sur l'activité observée au niveau du lobe temporal médian de façon bilatérale ce qui pourrait donc expliquer une difficulté de stockage de l'information. / With advancing age, the efficiency of all cognitive functions, especially episodic memory, tends to decrease. The study of Dm and old/new effects and of the results of the sLORETA method allowed to characterize, on a neurofunctionnal level, two types of non-pathological aging among seniors. On the one hand, stable cognitive aging results in encoding processes similar to those observed in young subjects while the retrieval processes require a bilateral recruitment of the medial temporal lobes, this activation being unilateral in young subjects. These results are in line with the HAROLD model, suggesting a reduction of hemispheric asymmetry with age. On the other hand, the altered cognitive aging might come from an alteration of brain networks at the early stage of the encoding phase. The decline of activity in the left prefrontal cortex, seat of executive functions, would suggest a difficult implementation of effective encoding strategies and have a direct impact on the activity observed in the medial temporal lobe bilaterally which could therefore explain information storage difficulties.

Inspection of the published research shows that sex differences in cognition in the general population have been widely cited with the direction of the advantage depending on the domain being examined. The most prevalent claims are that men are better than women at visuospatial and mathematical tasks whereas women have superior verbal skills and perform better than men on tasks assessing episodic memory. There is also some evidence that women are more accurate than men at identifying facial expressions of emotion. A more in-depth examination of the literature, however, reveals that evidence of such differences is not as conclusive as would at first appear. Not only is the direction and magnitude of sex differences dependent on the cognitive domain but also on the individual tasks. Some visuospatial tasks show no difference (e.g. figure copying) whist men have been shown to be better than women at confrontation naming (a verbal task). Alzheimer’s disease is a heterogeneous illness that affects the elderly. It manifests with deficits in cognitive abilities and behavioural difficulties. It has been suggested that some of the behavioural issues may arise from difficulties with recognising facial emotion expressions. There have been claims that AD affects men and women differently: women have been reported as being more likely to develop AD and showing a greater dementia severity than men with equivalent neuropathology. Despite this, research into sex differences in cognition in AD is scarce, and conflicting. This research was concerned with the effect of sex on the cognitive abilities of AD patients. The relative performance of men and women with AD was compared to that of elderly controls. The study focused on the verbal, visuospatial and facial emotion recognition domains. Data was collected and analysed from 70 AD patients (33 male, 37 female), 62 elderly controls (31 male, 31 female) and 80 young adults (40 male, 40 female). Results showed those with AD demonstrate cognitive deficits compared to elderly controls in verbal and visuospatial tasks but not in the recognition of facial emotions. There were no significant sex differences in either the young adults or the healthy elderly controls but sex differences favouring men emerged in the AD group for figure copying and recall and for confrontation naming. Given that elderly men and women perform equivalently for these tasks, this represents a deterioration in women’s cognitive abilities, relative to men’s. Further evidence of such an adverse effect of AD was apparent in other tasks, too: for most verbal and visuospatial tasks, either an effect favouring women in the elderly is reversed or a male advantage increases in magnitude. There is no evidence of sex differences in facial emotion recognition for any group. This suggests that the lack of published findings reporting on sex differences in this domain is due to the difficulty in getting null findings accepted for publication. The scarcity of research examining sex differences in other domains is also likely to be due to this bias.

L'objectif général de ce travail de thèse était d'étudier le phénomène de répétition stratégique et son évolution au cours du vieillissement normal et pathologique ; mais aussi de mettre en évidence les mécanismes impliqués lors du choix d'une stratégie. Pour atteindre ces objectifs, nous avons conduit trois études, pour lesquelles nous avons adopté une approche expérimentale où nous avons utilisé des stratégies arithmétiques (i.e., méthodes utilisées par un individu pour résoudre une tâche cognitive donnée). Nous avons recueilli nos données auprès d'individus jeunes, âgés sains et patients atteints de la maladie d'Alzheimer (i.e., MA). Les principaux résultats montraient que (a) les adultes âgés répétaient significativement plus que les adultes jeunes, et ce d'autant plus lorsque la stratégie était fortement active en mémoire de travail ; cependant, (b) ils réussissaient à changer de stratégie de manière comparable aux adultes jeunes lorsque les latences entre leurs réponses et les stimuli suivant augmentaient ; et (c) les patients atteints de la MA avaient plus de difficultés à sélectionner la meilleure stratégie que les adultes âgés, et ce d'autant plus lorsque le problème était difficile. Ce travail a donc permis de préciser les processus cognitifs impliqués lors de la sélection stratégique et de comprendre les effets du vieillissement normal et pathologique sur ceux-ci. Nous discutons également de l'implication possible de ces résultats quant aux modèles théoriques de la sélection stratégique. / The main goals of this thesis were (a) to study the strategy repetition phenomenon and its evolution during normal and pathological aging and (b) to highlight mechanisms involved in the strategy selection. To achieve these purposes, we collected strategy selection data from young, healthy older adults, and patients with Alzheimer's disease (i.e., AD). Our main results showed that (a) older adults repeated strategies significantly more than young adults, and especially when this strategy was highly active in working memory, however, (b) they were able to change strategies in a comparable way to young adults when latencies between their response and the next stimulus increased, and (c) AD patients had more difficulties selecting the best strategy than healthy older adults, especially on the most difficult problems (i.e., heterogeneous problems). This work helped in clarifying cognitive processes involved in strategy selection and in understanding effects of normal and pathological aging. We also discuss the implications of these results for theoretical models of strategyselection.

Rechercher de l’information sur Internet avec un moteur de recherche est une activité complexe qui exige des utilisateurs un grand nombre de traitements. Les travaux de recherche sur les effets du vieillissement en RI ont montré que les utilisateurs âgés ont de moins bonnes performances, passent plus de temps à évaluer les pages de résultats du moteur de recherche et reformulent moins que les jeunes. Ces difficultés seraient dues au déclin des habiletés cognitives fluides comme la flexibilité cognitive, la vitesse de traitement ou le rafraichissement en mémoire de travail. Pour comprendre comment le vieillissement cognitif affecte l’activité de RI, nos travaux ont investigué les stratégies de recherche élaborées par les utilisateurs jeunes et âgés ainsi que les processus cognitifs impliqués. La première partie de ce travail s’est attaché à étudier, au travers de 2 expérimentations, comment les connaissances antérieures peuvent soutenir l’activité de recherche des utilisateurs plus âgés et les aider à répondre aux exigences de la RI selon le niveau de complexité des tâches de recherche. La deuxième partie du travail de recherche a investigué le rôle de deux dispositifs d’aide à la RI : l’un maximisant les effets bénéfiques des connaissances antérieures par un dispositif de pré-activation (étude 3), et l’autre soutenant le maintien du but en mémoire de travail (étude 4). Nos résultats ont montré que les utilisateurs plus âgés ont davantage de difficultés que les jeunes à évaluer les pages de résultats du moteur de recherche et à reformuler leurs requêtes (ils produisent moins de nouveaux mots clés et utilisent plus de mots clés issus des problèmes de recherche). En outre, la phase initiale de l’activité de recherche s’est avérée être plus critique pour les adultes âgés qui produisent des requêtes initiales moins élaborées et passent plus de temps sur la première page de résultats du moteur de recherche. Les connaissances antérieures sur le domaine peuvent toutefois soutenir le niveau d’élaboration des requêtes des utilisateurs plus âgés et améliorer les stratégies de recherche. Par ailleurs, pré-activer les connaissances antérieures peut soutenir l’élaboration de stratégies de recherche descendantes et améliorer le contenu sémantique des requêtes des âgés (particulièrement dans un domaine pour lequel ils ont de faibles connaissances antérieures). Enfin, l’outil d’aide soutenant le maintien du but en mémoire de travail favorise des stratégies de recherche plus flexibles en améliorant la reformulation des requêtes (temps de reformulation plus courts) et en aidant l’exploration en début d’activité. Ces travaux de recherche posent les bases d’un nouveau modèle cognitif de l’activité des RI pour les utilisateurs plus âgés. / Searching for information with a search engine is a complex activity that requires users to perform a series of cognitive processes. Prior works showed that older users can have lower search performance, they spent more time on the search engine result pages and they produce fewer queries than young ones. Older users’ difficulties are mainly caused by the age-related decline of fluid abilities such as cognitive flexibility, processing speed or update in working memory. To understand the effects of aging on information search with a search engine, we studied the search strategies elaborated and the cognitive processes involved by young and older adults. The first part of the present work investigated how prior knowledge about the search topic can support older users’ on-line search behavior and help them deal with the search task complexity (2 experiments). The second part of our work analyzed the role of two information search support tools. One tool aimed at optimizing the benefits of domain knowledge by pre-activating prior knowledge (experiment 3) whereas the other aimed at supporting search goal refreshing in working memory (experiment 4). Results showed that older users had more difficulties evaluating the search engine results pages and reformulating than young ones (i.e. they produced fewer new keywords and used more keywords extracted from the search problem statement in their queries). The initial stage of the search represented a challenge for older users who formulated initial queries that were less elaborate and spent longer dwell time on the first search engine page than young ones. Prior knowledge can improve older users’ reformulation and support more elaborate search strategies. In addition, pre-activating prior knowledge can foster top-down search strategies and improve the semantic content of the queries produced by older users (especially in a domain for which they have low prior knowledge). The support tool helping search goal refreshing in working memory fostered more flexible search strategies and improved reformulation (i.e. reduced the time needed by older users to reformulate). Eventually, our research work led us to elaborate a new cognitive model of information search with a search engine that takes into account the role of aging.

Der vorliegende Arbeit systematisiert Befunde aus dem Gebiet der exekutiven Funktionen und ihren Modulationen durch verschiedene Parameter (d.h. Shifting, Inhibition, Updating, Dual tasking). Diese Parameter werden in einer entsprechenden Rahmenkonzeption illustriert und umfassen die Parameter Kontext, Training, Alter und ihre Kombinationen. Die vorliegende Arbeit zeigt Beispiele, wie diese Parameter in Bezug auf exekutive Funktionen realisiert werden können. Im Rahmen des Kontext-Parameters wird beispielsweise gezeigt, wie die Vorhersagbarkeit von Aufgaben und Aufgabenreihenfolgen Dual tasking (Heinrich et al., 2012) und wie aktuelle Anforderungen an das Arbeitsgedächtnis Inhibition (Soutschek et al., 2013) modulieren kann. Allerdings zeigen Töllner et al. (2012) auch Grenzen des Kontext-Parameters bei der Modulation der erstgenannten exekutiven Funktion. Der Parameter Training wurde realisiert mit Fokus auf (1) Shifting (Strobach et al., 2012a) und (2) Updating (Salminen et al., 2011, 2012). Schubert and Strobach (2012) sowie Strobach et al. (2012b) untersuchten den Transfereffekt von Video-game- und Arbeitsgedächtnistraining auf Dual tasking und Shifting. Schließlich zeigen Strobach et al. (2012c, 2012d) Modulationseffekte bei der Kombination des Alters- und Trainingsparameters auf die exekutive Funktion Dual tasking. Abschließend systematisiert die vorgestellte Rahmenkonzeption die Lücken und Ziele zukünftiger Forschung zur Modulation von exekutiven Funktionen. / The present review aims at a systematization of findings in the field of executive functions and their modulation due to different operational parameters (i.e., dimensions). This systematization is realized in the form of the Framework on modulations of executive functions. Basically, this framework illustrates how different types of executive functions (i.e., Shifting, Inhibition, Updating, Dual tasking) are modulated by their context (Context dimension), training (Training dimension), age (Age dimension), and combinations of these dimensions. The present review includes examples of studies that demonstrate a realization of each of these dimensions and their effects on executive function types. In detail, the Context dimension modulates the executive function type Dual tasking (i.e., due to task order predictability in dual tasks; Hendrich et al., 2012 ) and Inhibition (i.e., due to the level of concurrent working memory demand in a Stroop task; Soutschek et al., 2013); however, Töllner et al. (2012) demonstrated that Context also affects processes that are not related with executive functioning (i.e., perception and motor processes) in a dual-task situation. The framework’s Training dimension was realized when (1) Strobach et al. (2012a) investigated effects of training on the executive function Shifting in a task switching situation and (2) Salminen et al. (2011, 2012), Schubert and Strobach (2012), as well as Strobach et al. (2012b) investigated transfer effects on executive functioning of Dual tasking and Shifting after video game and working memory training. Finally, Strobach et al. (2012c, 2012d) illustrated modulation effects of age and training (i.e., the combination of Age and Training dimension) on the executive function type Dual tasking. In sum, this framework helps to systematize research gaps and future studies in this field (i.e., executive functions).