Age Differences in the Organization and Acquisition-Forgetting Processes in a Multi-Free-Recall Task

Cette étude s’adresse aux relations entre les processus d’organisation et les processus d’acquisition et d’oubli.Vingt-deux participants jeunes et 22 participants âgés ont été soumis à deux tâches de rappels libres successifs (3 présentations suivies chacune d’un rappel) variant par la nature du matériel à mémoriser (liste de mots reliés vs. non reliés).  Les performances obtenues à chaque essai de rappel ont été analysées en termes de nombre de mots rappelés, de mesures d’organisation (scores PF et ARC) et de gains / pertes (mots gagnés ou perdus entre deux essais) (Dunlosky & Salthouse, 1996). Les résultats indiquent que les essais successifs sont plus bénéfiques pour les âgés lorsque le matériel est relié révélant ainsi une difficulté à auto-initier les processus d’organisation. Aussi, cette difficulté intéresse principalement la composante épisodique des mécanismes d’organisation (effet significatif de l’âge sur les scores PF) plutôt que la composante sémantique (absence d’effet d’âge sur les scores ARC). De plus, les résultats portant sur les gains et les pertes indiquent que les mécanismes d’acquisition jouent un rôle plus important dans les différences liées à l’âge dans l’apprentissage d’un matériel non-relié alors que les processus d’oubli contribuent  plus  aux difficultés d’apprentissage d’un matériel relié. Enfin, la composante épisodique des mécanismes d’organisation semble jouer un rôle préventif contre l’oubli (corrélation négative entre les pertes et les scores PF) chez les participants jeunes, et ce rôle est diminué avec l’âge.This study addressed the relationships between organizational processing and acquisition / forgetting processes. Twenty-two young and 22 older adults were tested using three study and free-recall test trials involving related or unrelated words. Performances in all trials were analyzed in terms of the number of words recalled, clustering measures (PF and ARC), and words gained and lost (Dunlosky & Salthouse, 1996). For material manipulation, the older group benefited more from repeated trials when the words were related, indicating that organizational processes are less spontaneously initiated with age. This finding is confirmed by a significant age effect on the episodic component of organizational processing (PF clustering scores), but no age effect on its semantic component (ARC scores). For gain and loss scores, gains (acquisition processes) played a major role in age differences in the learning of unrelated words while losses (forgetting processes) had more impact on the learning of related words. In addition, the correlational results indicated that the episodic organization component (PF scores) seemed to prevent item losses in the younger group, whereas it was less salient in the older adults

Role of cognitive resources on everyday functioning among oldest-old physically frail

International audienceBackground : Everyday functioning becomes a challenge with aging, particularly among frail oldest-old adults. Several factors have been identified as influencing everyday activities realization, including physical and cognitive functioning. However, the influence of cognitive resources as a compensatory factor in the context of physical frailty deserves further consideration.Aims :This study aims to investigate in older adults physically frail the possible compensatory role of cognitive resources to perform everyday tasks.Methods :Two groups of community-dwelling old participants (n = 26 per group) matched for their age and cognitive resources, have been drawn according to their level of physical functioning. Two measures of everyday functioning have been assessed: one self-reported by the participant (the IADL scale) and one performance-based measure (the TIADL tasks).Results: Participants performed equally the TIADL tasks irrespective of their physical condition. Contrariwise, participants with low physical functioning reported more everyday difficulties than their counterparts with a high level of physical functioning. Additionally, regressions analyses revealed differential influence of cognitive resources on performance and reported measures of everyday functioning.Discussion : Our data suggests that cognitive resources are more strongly involved in the performance-based IADL measure in situation of physical frailty. Additionally, for participants with low physical functioning, lower cognitive resources are associated with more perceived difficulties in everyday life.Conclusion: These results highlight the compensatory role of cognitive resources in physically frail older adults, and suggest that an overestimation of everyday difficulties compared to performance on IADL tasks is an early indicator of physical decline and cognitive compensation

Predicting mental imagery based BCI performance from personality, cognitive profile and neurophysiological patterns

Mental-Imagery based Brain-Computer Interfaces (MI-BCIs) allow their users to send commands to a computer using their brain-activity alone (typically measured by ElectroEncephaloGraphy— EEG), which is processed while they perform specific mental tasks. While very promising, MI-BCIs remain barely used outside laboratories because of the difficulty encountered by users to control them. Indeed, although some users obtain good control performances after training, a substantial proportion remains unable to reliably control an MI-BCI. This huge variability in user-performance led the community to look for predictors of MI-BCI control ability. However, these predictors were only explored for motor-imagery based BCIs, and mostly for a single training session per subject. In this study, 18 participants were instructed to learn to control an EEG-based MI-BCI by performing 3 MI-tasks, 2 of which were non-motor tasks, across 6 training sessions, on 6 different days. Relationships between the participants’ BCI control performances and their personality, cognitive profile and neurophysiological markers were explored. While no relevant relationships with neurophysiological markers were found, strong correlations between MI-BCI performances and mental-rotation scores (reflecting spatial abilities) were revealed. Also, a predictive model of MI-BCI performance based on psychometric questionnaire scores was proposed. A leave-one-subject-out cross validation process revealed the stability and reliability of this model: it enabled to predict participants’ performance with a mean error of less than 3 points. This study determined how users’ profiles impact their MI-BCI control ability and thus clears the way for designing novel MI-BCI training protocols, adapted to the profile of each user

Projet de vie : regard des adultes avec une trisomie 21 et des aidants (familles et professionnels)

Le projet de vie occupe une place centrale dans l’accompagnement de personnes en situation de handicap. En effet, avoir des projets a des répercussions favorables notamment sur l’inclusion sociale. Cette pré-étude fut réalisée dans le but de préciser cette notion ainsi que les enjeux qu’elle représente pour les personnes présentant une déficience intellectuelle (DI) et pour leur entourage. L’analyse d’entretiens permet de proposer une définition du projet de vie et de souligner les difficultés rencontrées par les différentes parties prenantes dans l’accompagnement des personnes avec DI. Suite à cette pré-étude, les chercheurs ont pu concevoir un assistant numérique d’aide à l’élaboration d’un projet de vie répondant aux remarques et difficultés soulevées par les futurs utilisateurs et l’ensemble des personnes concernées.The life plan has a central role in supporting people with disabilities. Indeed, having projects has a positive impact, particularly on social inclusion. A pre-study has been conducted to clarify this notion, as well as its issues for people with intellectual disability (ID) and their entourage. The analysis of interviews allows to propose a definition of the life plan and to highlight the difficulties encountered by the different stakeholders in the accompaniment of people with ID. Following this pre-study, researchers were able to design a digital assistant to assist in the development of a life plan responding to the remarks and difficulties raised by future users and all those concerned

Estimation of Distances in 3D by Orthodontists Using Digital Models

In the field of orthodontics, digital dental arch models are increasingly replacing plaster models in orthodontic diagnostics. This change in interface from physical plaster models to digital image-based models raises the question of how orthodontists interpret intra- and inter-arch relationships from an image on a screen. In particular, the issue of the accuracy of the distances estimated on numerical models is crucial since the estimation of distances is the basis of the therapeutic decision-making process. Studies have shown that distances were well estimated on plaster models, but no study has verified this point on numerical models. This is the question that our study addresses. The experimental protocol consisted of collecting estimates of measurements made by orthodontists using digital models. The reliability of these measurements was then assessed by comparing them to the actual physical distances. We asked 31 orthodontists (19 women and 12 men; an average age of 37 years) to generate 3D model-based measurements of seven different elements: mandibular congestion, the maxillary intermolar distance, Spee’s curve, 16/26 symmetry, the right canine class, overbite, and overjet. These values were then compared to the actual measurements calculated using Insignia® software (ORMCO Corporation: Brea, CA, USA), using single sample t-tests. This test makes it possible to compare a distance estimated by the participants with a reference value, which corresponds here to the real distance. The results indicate that, overall, the distance estimates made on the 3D models differ significantly from the actual distances measured using the Insignia® software. This was particularly so for mandibular crowding (test value = 0; t (30) = 10.74; p ≤ 0.01), test value = 1; t (30) = 6.23; p ≤ 0.01). Although no study has focused on distance estimation on numerical models in the field of orthodontics, our results agree with the conclusions of studies showing that distances are not estimated in the same way in real environments and virtual environments. Additional studies will make it possible to identify more clearly the parameters (individual factors, equipment, etc.), which make it possible to improve the estimation of distances in the practice of orthodontics. In any case, these studies are necessary to improve the training of future practitioners in the use of virtual models for decision-making and to support them in the digital transition

Identifying factors influencing the outcome of BCI-based post stroke motor rehabilitation towards its personalization with Artificial Intelligence

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Independent linear discriminant analysis : The first step in including covariates in EEG classification

International audienceThe classifiers commonly used in BCIs do not take into account covariates such as changes in users’ mental states, eg., motivation or fatigue, which can influence EEG dynamic [1] and affect classification performances. We propose a linear discriminant analysis (LDA) variant [2] to account for these interfering covariates and improveperformance

Towards including patient-specific factors in BCI-based post-stroke rehabilitation using artificial intelligence

International audienceStroke is the leading cause of complex disability. Indeed, 40% of person suffering from stroke present loss for motor function in their upper limp. Promising results have been shown with brain-computer interfaces (BCI) for improving motor rehabilitation. Recent meta-analysis have shown positive effects of BCI on motor rehabilitation of stroke patients. Most studies give a sensory feedback that can be either kinetic (robotic orthosis or neuromuscular electrical stimulation) or visual. The training seems to be more efficient when it includes somatosensory feedback. However, some issues need to be addressed to popularize BCI in hospitals. Two aspects in particular need to be improved: the personalisation of the training by taking into account the specificity of users (demographics data, cognitive and personality profiles, mental states) and the improvement of the classification performances including data of the profile and states of the user. Among the factors related to users, the somatosensory impairments related to the stroke certainly plays an important role in the motor recovery capacities, but this factor is not often taken into account. Considering user’s characteristics to improve the effects of BCI is a challenge that could be addressed with artificial intelligence (AI) algorithms. However this approach requires a better understanding of the factors affecting BCI-based post-stroke motor recovery in order to calibrate the algorithms used. In this presentation, we elaborate on the state-of-the-art of the individual factors that influence BCI motor rehabilitation. Also, we present the protocol of our study, which objective is to collect data regarding patients’ characteristics (demographic, cognitive, and personality) that would allow us to identify which patients best benefit from BCI-based motor recovery. Particular attention will be paid to the effect of stroke-related somatosensory impairment, fatigue and attention on post-stroke motor rehabilitation by BCI

Transfer of spatial knowledge from a virtual environment to reality: Impact of route complexity and subject’s strategy on the exploration mode

The use of virtual reality as tool in the area of spatial cognition raises the question of the quality of learning transfer from a virtual to a real environment. It is first necessary to determine with healthy subjects, the cognitive aids that improve the quality of transfer and the conditions required, especially since virtual reality can be used as effective tool in cognitive rehabilitation. The purpose of this study was to investigate the influence of the exploration mode of virtual environment (Passive vs. Active) according to Route complexity (Simple vs. Complex) on the quality of spatial knowledge transfer in three spatial tasks. Ninety subjects (45 men and 45 women) participated. Spatial learning was evaluated by Wayfinding, sketch-mapping and picture classification tasks in the context of the Bordeaux district. In the Wayfinding task, results indicated that active learning in a Virtual Environment (VE) increased the performances compared to the passive learning condition, irrespective of the route complexity factor. In the Sketch-mapping task, active learning in a VE helped the subjects to transfer their spatial knowledge from the VE to reality, but only when the route was complex. In the Picture classification task, active learning in a VE when the route was complex did not help the subjects to transfer their spatial knowledge. These results are explained in terms of knowledge levels and frame/strategy of reference [SW75, PL81, TH82]