Sleep Does not Help Relearning Declarative Memories in Older Adults

International audienceHow sleep affects memory in older adults is a critical topic, since age significantly impacts both sleep and memory. For declarative memory, previous research reports contradictory results, with some studies showing sleep-dependent memory consolidation and some other not. We hypothesize that this discrepancy may be due to the use of recall as the memory measure, a demanding task for older adults. The present paper focuses on the effect of sleep on relearning, a measure that proved useful to reveal subtle, implicit memory effects. Previous research in young adults showed that sleeping after learning was more beneficial to relearning the same Swahili-French word pairs 12 hours later, compared with the same interval spent awake. In particular, those words that could not be recalled were relearned faster when participants previously slept. The effect of sleep was also beneficial for retention after a one-week and a 6-month delay. The present study used the same experimental design in older adults aged 71 on average but showed no significant effect of sleep on consolidation, on relearning, or on long-term retention. Thus, even when using relearning speed as the memory measure, the consolidating effect of sleep in older adults was not demonstrated, in alignment with some previous findings

Four types of scrapie in goats differentiated from each other and bovine spongiform encephalopathy by biochemical methods

Scrapie in goats has been known since 1942, the archetype of prion diseases in which only prion protein (PrP) in misfolded state (PrPSc) acts as infectious agent with fatal consequence. Emergence of bovine spongiform encephalopathy (BSE) with its zoonotic behaviour and detection in goats enhanced fears that its source was located in small ruminants. However, in goats knowledge on prion strain typing is limited. A European-wide study is presented concerning the biochemical phenotypes of the protease resistant fraction of PrPSc (PrPres) in over thirty brain isolates from transmissible spongiform encephalopathy (TSE) affected goats collected in seven countries. Three different scrapie forms were found: classical scrapie (CS), Nor98/atypical scrapie and one case of CH1641 scrapie. In addition, CS was found in two variants—CS-1 and CS-2 (mainly Italy)—which differed in proteolytic resistance of the PrPres N-terminus. Suitable PrPres markers for discriminating CH1641 from BSE (C-type) appeared to be glycoprofile pattern, presence of two triplets instead of one, and structural (in)stability of its core amino acid region. None of the samples exhibited BSE like features. BSE and these four scrapie types, of which CS-2 is new, can be recognized in goats with combinations of a set of nine biochemical parameters

Déficits attentionnels diurnes et syndrome d'apnées obstructives au cours du sommeil (évaluation des capacités cognitives)

La somnolence diurne excessive correspond à la principale plainte des patients présentant un syndrome d'apnées du sommeil. De ce fait, la vigilance diurne est la composante attentionnelle la plus souvent investiguée au cours de cette pathologie. L'objectif de ce travail a été de mettre en évidence l'étendu des déficits attentionnels des patients apnéiques, afin de comprendre si seule la somnolence pouvaient expliquer les atteintes cognitives de ces patients. Nos résultats ont mis en évidence que l'ensemble des fonctions attentionnelles étaient déficitaires, la vigilance, mais également l'attention sélective et divisée ainsi que le contrôle exécutif de l'attention pouvaient être altérés de façon spécifique et isolée. Notre recherche menée en situation réelle de conduite automobile a également montré que ces patients présentaient un allongement marqué de leurs temps de réaction au volant et que ces performances étaient corrélées avec celles d'un test d'attention divisée réalisé en laboratoire. L'ensemble de ces résultats indique que les patients apnéiques présentent un déficit attentionnel multiple n'impliquant pas uniquement la vigilance diurne.Excessive daytime sleepiness represents the major complaint of patients with obstructive sleep apnea (OSA). As a result, daytime vigilance is the most frequently examined component of attention in this disorder. The overall aim of this work was to establish the depth of attention deficits in OSA patients, in order to investigate whether sleepiness alone could explain cognitive deficits in these patients. Our results show that all attentional functions were altered, vigilance but also selective and divided attention as well as executive control of attention could be specifically altered. In addition, our work in a real automobile driving setting showed that OSA patients exhibited a marked increase in their reaction time while driving and that these performances were correlated with a laboratory setting divided attention test. Our findings indicate that OSA patients suffer from a multiple attentional deficit which does not implicate daytime vigilance exclusively.GRENOBLE1-BU Médecine pharm. (385162101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Ouverture de la journée "Les jeunes, le numérique, regards croisés sur des usages"

Ouverture de la journée "Les jeunes, le numérique, regards croisés sur des usages" par Pascal Robert, directeur de recherche à l’Enssib et Stéphanie Mazza, directrice adjointe de la recherche à l’Insp

How Sleep Affects Relearning and Long-Term Retention: Age Matters

International audienceIn young adults, sleeping after learning has been shown to facilitate relearning and long-term retention, compared to staying awake (Mazza et al., in revision). Children (aged 8) and elderly people (aged 71) learned Swahili-French word pairs to criterion during a learning session taking place in the morning or evening (Wake and Sleep group, respectively). Participants spent 12 hours filled with wakefulness or a night of sleep, then performed a relearning session to criterion either in the evening (Wake) or the following morning (Sleep). One week later, retention was tested. Sleep appeared to affect memory differently according to age. The groups of children did not differ during the relearning session whereas the Sleep outperformed the Wake group after one week. In elderly participants, no effect of sleep was observed. Thus, the enhancing effect of sleep is most pronounced inadults, moderate in children, and weak in elderly people

A comprehensive literature review of chronic pain and memory

International audienceChronic pain patients often complain of their "poor memory" and numerous studies objectively confirmed such difficulties in reporting working memory (WM) and long-term memory (LTM) dysfunctions. This paper provides a comprehensive review of the literature on memory impairment in chronic pain (CP) patients. Twenty-four observational studies evaluating WM or/and LTM in a chronic pain group and a control group were included in this review. Results showed that studies consistently reported a moderate decline, in both WM and LTM performances in CP patients. Even if CP patients complained about forgetfulness, objective measurements did not permit to conclude to a long-term storage impairment. CP patients exhibited more specifically encoding or retrieving difficulties compared to controls. Results showed that chronic pain selectively impacted the most attention-demanding memory processes, such as working memory and recollection in long-term memory. Results also demonstrated that CP patients exhibited a memory bias directed towards painful events compared to control subjects. Several authors have suggested that CP could be a maladaptive consequence of memory mechanisms. The long-lasting presence of pain continuously reinforces aversive emotional associations with incidental events. The inability to extinguish this painful memory trace could explain the chronic persistence of pain even when the original injury has disappeared. A major concern is the need to extricate pain-related cognitive effects from those resulting from all the co-morbidities associated with CP which both have a deleterious effect on cognitive function

How Sleep Affects Relearning and Long-Term Retention: Age Matters

International audienceIn young adults, sleeping after learning has been shown to facilitate relearning and long-term retention, compared to staying awake (Mazza et al., in revision). Children (aged 8) and elderly people (aged 71) learned Swahili-French word pairs to criterion during a learning session taking place in the morning or evening (Wake and Sleep group, respectively). Participants spent 12 hours filled with wakefulness or a night of sleep, then performed a relearning session to criterion either in the evening (Wake) or the following morning (Sleep). One week later, retention was tested. Sleep appeared to affect memory differently according to age. The groups of children did not differ during the relearning session whereas the Sleep outperformed the Wake group after one week. In elderly participants, no effect of sleep was observed. Thus, the enhancing effect of sleep is most pronounced inadults, moderate in children, and weak in elderly people