Working memory impairment in pilots exposed to acute hypobaric hypoxia.

INTRODUCTION: During an acute hypoxia exposure, impairment of memory is one of the most frequently reported symptoms, either during hypoxia awareness training of aircrews or after an in-flight hypoxic incident. However, the effects of acute hypoxia on memory have been little studied in laboratory-controlled conditions. Moreover, none of these studies were performed in hypobaric conditions. The main aim of our study was to investigate the effects of acute hypobaric hypoxia on working memory (WM). This study also aimed to find links between physiological measurements and cognitive performance during acute hypoxia exposure. METHODS: During hypoxia awareness training, 28 subjects (experimental group) were exposed to a simulated altitude level of 10,000 m (31,000 ft) in a hypobaric chamber, while 29 subjects (control group) stayed at sea level. WM was assessed in both groups with the Paced Auditory Serial Addition Test (PASAT). Peripheral oxygen saturation (SpO2) and heart rate were recorded. RESULTS: WM was strongly impaired in the hypoxic group. One major finding is that hypoxia highly increased the mean error frequency rate. WM performance decreased linearly with hypoxemia, but SpO2 was weakly predictive of PASAT performance and vice versa. DISCUSSION: WM is impaired by acute hypobaric hypoxia. Given the importance of WM in aircraft piloting and its sensitivity to hypoxia, the PASAT, in association with SpO2 and EEG recordings, could improve both hypoxia training and our understanding of the effects of hypoxia on memory.

Neutralizing antibody response to SARS-CoV-2 persists 9 months post symptom onset in mild and asymptomatic patients.

OBJECTIVE: A better understanding of the immune response against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is critical to predict its dynamics within the general population and its impact on the vaccination strategy. This study assessed the persistence of neutralizing antibody (Nab) activity and SARS-CoV-2 serology in serum samples of mild and asymptomatic patients 9 months post symptom onset (PSO) in a primary care context among immunocompetent adults. METHODS: A longitudinal cohort of crew members (CMs) exposed to coronavirus disease 2019 (COVID-19) during an outbreak of SARS-CoV-2 on the French aircraft carrier 'Charles de Gaulle' in April 2020 was created. CMs infected with COVID-19 and with positive serology at the end of quarantine were tested 9 months PSO. Samples were collected 18 and 280 days PSO. For each patient, both serology and serum viral neutralizing activity were performed. RESULTS: In total, 86 CMs were analysed. Samples were collected 18 and 280 days PSO. The seroconversion rates were 100% and 93% (82/86) at 18 and 280 days PSO, respectively, and 72.7% of patients exhibited persistent Nab activity at 9 months, regardless of disease severity. CONCLUSION: Nab activity persists for up to 9 months following asymptomatic/mild COVID-19 among young adults, regardless of serological results.

Resilience after trauma: The role of memory suppression.

In the aftermath of trauma, little is known about why the unwanted and unbidden recollection of traumatic memories persists in some individuals but not others. We implemented neutral and inoffensive intrusive memories in the laboratory in a group of 102 individuals exposed to the 2015 Paris terrorist attacks and 73 nonexposed individuals, who were not in Paris during the attacks. While reexperiencing these intrusive memories, nonexposed individuals and exposed individuals without posttraumatic stress disorder (PTSD) could adaptively suppress memory activity, but exposed individuals with PTSD could not. These findings suggest that the capacity to suppress memory is central to positive posttraumatic adaptation. A generalized disruption of the memory control system could explain the maladaptive and unsuccessful suppression attempts often seen in PTSD, and this disruption should be targeted by specific treatments.

Feasibility of high-throughput sequencing in clinical routine cancer care: lessons from the cancer pilot project of the France Genomic Medicine 2025 plan.

BACKGROUND: Whole exome sequencing and RNA sequencing (WES/RNASeq) should now be implemented in the clinical practice in order to increase access to optimal care for cancer patients. Providing results to Tumour Boards in a relevant time frame-that is, compatible with the clinical pathway-is crucial. Assessing the feasibility of this implementation in the French care system is the primary objective of the Multipli study, as one of the four pilot projects of the national France Genomic Medicine 2025 (FGM 2025) plan. The Multipli study encompasses two innovative trials which will be driven in around 2400 patients suffering from a soft-tissue sarcoma (Multisarc) or a metastatic colorectal carcinoma (Acompli). METHODS: Prior to launching the FGM 2025 cancer pilot study itself, the performance of the Multipli genomic workflow has been evaluated through each step, from the samples collection to the Molecular Tumour Board (MTB) report. Two Multipli-assigned INCa-labelled molecular genetics centres, the CEA-CNRGH sequencing platform and the Institut Bergonié's Bioinformatics Platform were involved in a multicentric study. The duration of each step of the genomic workflow was monitored and bottlenecks were identified. RESULTS: Thirty barriers which could affect the quality of the samples, sequencing results and the duration of each step of the genomic pathway were identified and mastered. The global turnaround time from the sample reception to the MTB report was of 44 calendar days. CONCLUSION: Our results demonstrate the feasibility of tumour genomic analysis by WES/RNASeq within a time frame compatible with the current cancer patient care. Lessons learnt from the Multipli WES/RNASeq Platforms Workflow Study will constitute guidelines for the forthcoming Multipli study and more broadly for the future clinical routine practice in the first two France Genomic Medicine 2025 platforms.

Brief Working Memory and Physiological Monitoring During a High-Altitude Expedition.

Malle, Carine, Benoît Ginon, and Cyprien Bourrilhon. Brief working memory and physiological monitoring during a high-altitude expedition. High Alt Med Biol. 17:359-364, 2016.-Background: Various studies have shown the deleterious effects of high-altitude hypoxia on cognitive functions, including attention and memory. Since optimal cognitive abilities may be crucial for mountain safety, this study was aimed to assess the relevance of a brief working memory test to quickly assess cognition at high altitude. METHODS: A set of physiological and cognitive measurements were collected from four professional climbers at various time points during the course of an expedition to Shishapangma (8043 m). RESULTS: Progressive high-altitude exposure induced a classical physiological response (i.e., decreased SpO2 and increased heart rate). Except for the final ascent, no participants suffered from acute mountain sickness and perceived exertion remained low. With the exception of an increased number of night awakenings, reported sleep quality was good. No working memory decline was observed in any of the participants, even at the highest altitudes. CONCLUSION: Altogether, these findings show that the participants were properly acclimatized to altitude. They also highlight the technical feasibility of assessing cognitive functions all along high-altitude expeditions. The direct access of such tools on a smartphone may improve mountain climbing safety.

Physiological and Cognitive Effects of Acute Normobaric Hypoxia and Modulations from Oxygen Breathing.

INTRODUCTION: The emergence of normobaric devices for hypoxia awareness training makes crucial the study of physiological and cognitive effects induced by acute normobaric hypoxia (NH) exposure. Our study aimed to 1) investigate the effects of acute NH exposure on physiological variables and working memory; and 2) investigate the physiological and cognitive effects of oxygen breathing before and after acute NH exposure. METHODS: There were 86 healthy men who were randomized into 4 groups: the Normoxia-Air group (N = 23), whose subjects were breathing air; the Hypoxia-Air group (N = 22), where NH exposure was preceded and followed by air breathing; the Normoxia-O2group (N = 21), whose protocol was similar to the Normoxia-Air group, except with the addition of 100% O2breathing periods; and the Hypoxia-O2group (N = 20), whose participants were exposed to 100% O2before and after NH exposure. Working memory was assessed with the Paced Auditory Serial Addition Test. Peripheral oxygen saturation (Spo2), heart rate (HR), and electroencephalogram (EEG) were recorded. RESULTS: Acute NH exposure induced a classical physiological response (i.e., decreased Spo2and increased HR), but not identical to the well-described physiological response to acute hypobaric hypoxia. Acute NH also caused a strong impairment in working memory. Oxygen breathing following NH exposure induced a slowing in the EEG associated with a worsening of working memory performance. DISCUSSION: Acute NH exposure revealed a good surrogate for the classical hypobaric chamber for refresher hypoxia awareness training. Because the association between hypoxia and hyperoxia seems deleterious for the brain, we suggest that NH exposure should be surrounded by air breathing.

[The role of sleep in memory consolidation: effects of age and Alzheimer's disease]. / Le rôle du sommeil dans la consolidation mnésique : effets de l'âge et de la maladie d'Alzheimer.

Sleep favors memory consolidation. Studies conducted in recent years allowed to reveal the neurobiological underpinnings underlying the beneficial effect of sleep on memory. They also have led to the proposal of two theoretical models: the "hippocampo-neocortical dialogue" and the "synaptic downscaling hypothesis". Normal ageing and, even more markedly Alzheimer's disease, are associated with sleep changes that may alter sleep-dependent memory consolidation. This paper presents a review of studies investigating the relationships between sleep and memory and how these links are affected by ageing and Alzheimer's disease.