Learning-by-Concordance (LbC): introducing undergraduate students to the complexity and uncertainty of clinical practice

Background: A current challenge in medical education is the steep exposure to the complexity and uncertainty of clinical practice in early clerkship. The gap between pre-clinical courses and the reality of clinical decision-making can be overwhelming for undergraduate students. The Learning-by-Concordance (LbC) approach aims to bridge this gap by embedding complexity and uncertainty by relying on real-life situations and exposure to expert reasoning processes to support learning. LbC provides three forms of support: 1) expert responses that students compare with their own, 2) expert explanations and 3) recognized scholars’ key-messages.Method: Three different LbC inspired learning tools were used by 900 undergraduate medical students in three courses: Concordance-of-Reasoning in a 1st-year hematology course; Concordance-of-Perception in a 2nd-year pulmonary physio-pathology course, and; Concordance-of-Professional-Judgment with 3rd-year clerkship students. Thematic analysis was conducted on freely volunteered qualitative comments provided by 404 students.Results:  Absence of a right answer was challenging for 1st year concordance-of-reasoning group; the 2nd year visual concordance group found radiology images initially difficult and unnerving and the 3rd year concordance-of-judgment group recognized the importance of divergent expert opinion.Conclusions: Expert panel answers and explanations constitute an example of “cognitive apprenticeship” that could contribute to the development of appropriate professional reasoning processes

Gray matter hypertrophy and thickening with obstructive sleep apnea in middle-aged and older adults

Rationale: Obstructive sleep apnea causes intermittent hypoxemia, hemodynamic fluctuations, and sleep fragmentation, all of which could damage cerebral gray matter that can be indirectly assessed with neuroimaging. Objectives: To investigate whether markers of obstructive sleep apnea severity are associated with gray matter changes among middle-aged and older individuals. Methods: Seventy-one subjects (ages: 55 to 76; apnea–hypopnea index: 0.2 to 96.6 events/h) were evaluated with magnetic resonance imaging. Two techniques were used: 1) voxel-based morphometry, which measures gray matter volume and concentration; 2) FreeSurfer automated segmentation, which estimates the volume of predefined cortical/subcortical regions and cortical thickness. Regression analyses were performed between gray matter characteristics and markers of obstructive sleep apnea severity (hypoxemia, respiratory disturbances, sleep fragmentation). Measurements and Main Results: Subjects had few symptoms, i.e. sleepiness, depression, anxiety and cognitive deficits. While no association was found with voxel-based morphometry, FreeSurfer revealed increased gray matter with obstructive sleep apnea. Higher levels of hypoxemia correlated with increased volume and thickness of the left lateral prefrontal cortex as well as increased thickness of the right frontal pole, the right lateral parietal lobules, and the left posterior cingulate cortex. Respiratory disturbances positively correlated with right amygdala volume while more severe sleep fragmentation was associated with increased thickness of the inferior frontal gyrus. Conclusions: Gray matter hypertrophy and thickening were associated with hypoxemia, respiratory disturbances, and sleep fragmentation. These structural changes in a group of middle-aged and older individuals may represent adaptive/reactive brain mechanisms attributed to a presymptomatic stage of obstructive sleep apnea

Obstructive sleep apnea during REM sleep and daytime cerebral functioning : a regional cerebral blood flow study using high-resolution SPECT

Obstructive sleep apnea (OSA) predominantly during rapid eye movement (REM) sleep may have impacts on brain health, even in milder OSA cases. Here, we evaluated whether REM sleep OSA is associated with abnormal daytime cerebral functioning using high-resolution single-photon emission computed tomography (SPECT). We tested 96 subjects (25 F, age: 65.2 ± 6.4) with a wide range of OSA severity from no OSA to severe OSA (apnea–hypopnea index: 0–97 events/h). More respiratory events during REM sleep were associated with reduced daytime regional cerebral blood flow (rCBF) in the bilateral ventromedial prefrontal cortex and in the right insula extending to the frontal cortex. More respiratory events during non-REM (NREM) sleep were associated with reduced daytime rCBF in the left sensorimotor and temporal cortex. In subjects with a lower overall OSA severity (apnea–hypopnea index<15), more respiratory events during REM sleep were also associated with reduced daytime rCBF in the insula and extending to the frontal cortex. Respiratory events that characterized OSA during NREM versus REM sleep are associated with distinct patterns of daytime cerebral perfusion. REM sleep OSA could be more detrimental to brain health, as evidenced by reduced daytime rCBF in milder forms of OSA

Altered resting-state functional connectivity patterns in late middle-aged and older adults with obstructive sleep apnea

IntroductionObstructive sleep apnea (OSA) is increasingly recognized as a risk factor for cognitive decline, and has been associated with structural brain alterations in regions relevant to memory processes and Alzheimer’s disease. However, it is unclear whether OSA is associated with disrupted functional connectivity (FC) patterns between these regions in late middle-aged and older populations. Thus, we characterized the associations between OSA severity and resting-state FC between the default mode network (DMN) and medial temporal lobe (MTL) regions. Second, we explored whether significant FC changes differed depending on cognitive status and were associated with cognitive performance.MethodsNinety-four participants [24 women, 65.7 ± 6.9 years old, 41% with Mild Cognitive Impairment (MCI)] underwent a polysomnography, a comprehensive neuropsychological assessment and a resting-state functional magnetic resonance imaging (MRI). General linear models were conducted between OSA severity markers (i.e., the apnea-hypopnea, oxygen desaturation and microarousal indices) and FC values between DMN and MTL regions using CONN toolbox. Partial correlations were then performed between OSA-related FC patterns and (i) OSA severity markers in subgroups stratified by cognitive status (i.e., cognitively unimpaired versus MCI) and (ii) cognitive scores in the whole sample. All analyzes were controlled for age, sex and education, and considered significant at a p &lt; 0.05 threshold corrected for false discovery rate.ResultsIn the whole sample, a higher apnea-hypopnea index was significantly associated with lower FC between (i) the medial prefrontal cortex and bilateral hippocampi, and (ii) the left hippocampus and both the posterior cingulate cortex and precuneus. FC patterns were not associated with the oxygen desaturation index, or micro-arousal index. When stratifying the sample according to cognitive status, all associations remained significant in cognitively unimpaired individuals but not in the MCI group. No significant associations were observed between cognition and OSA severity or OSA-related FC patterns.DiscussionOSA severity was associated with patterns of lower FC in regions relevant to memory processes and Alzheimer’s disease. Since no associations were found with cognitive performance, these FC changes could precede detectable cognitive deficits. Whether these FC patterns predict future cognitive decline over the long-term needs to be investigated

Dynamique sédimentaire du littoral de Sables d'Or les Pins (Côtes d'Armor)

Located on the eastern coast of St Brieuc bay, the Sables d’Or les Pins beach is formed by a sand spit, covered by dunes, isolating an internal lagoon from the sea. Morphological, topographical and sedimentological surveys emphasize the coastal evolution : erosion processes occur at the eastern part of the spit whereas longshore current produces sand drifting towards the western head of the spit.La plage des Sables d'Or les Pins, située sur la côte Est de la baie de Saint-Brieuc, est adossée à une flèche littorale sableuse surmontée de massifs dunaires. La flèche s'étend d'Est en Ouest sur une longueur de près de 2 km et subit des érosions importantes dans sa partie centrale, tandis que son extrémité progresse vers l'Ouest, isolant derrière elle une lagune en voie de colmatage. L'analyse morphologique, topographique et sédimentologique du site permet de mettre en évidence la dynamique sédimentaire qui y règne et de suivre son évolution. L'érosion des massifs dunaires et le recul du trait de côte observé depuis plusieurs années nécessitent des aménagements en vue de protéger l'environnement et les installations de la station touristique des Sables d'Or.Bonnot-Courtois Chantal, Lafond Louis-Robert. Dynamique sédimentaire du littoral de Sables d'Or les Pins (Côtes d'Armor). In: Cahiers du Centre nantais de recherche pour l'aménagement régional, n°41-42, 1994. Défense des côtes ou protection de l'espace littoral, quelles perspectives ? Actes du colloque international (17-20 octobre 1991) pp. 106-115

Le laboratoire de géomorphologie de l'Ecole Pratique des Hautes Etudes en 1989-1990

Bonnot-Courtois C, Verger Fernand, Lafond Louis Robert, Le Rhun Jeannine. Le laboratoire de géomorphologie de l'Ecole Pratique des Hautes Etudes en 1989-1990. In: Norois, n°151, Juillet-Septembre 1991. pp. 315-322

What governs marine fouling assemblages on chemically-active antifouling coatings?

From an environmental perspective, there is a need to reduce the amount of biocides in chemically-active antifouling (AF) coatings, as these biocides can cause severe damage to marine life. In this study, six active molecules known as booster biocides were added at 3 wt% in solvent and aqueous-based acrylic paints. DCOIT, dichlofluanid, zinc pyrithione, copper pyrithione, tralopyril and zineb were used alone and mixed with a lower amount of copper (I) oxide and copper thiocyanate (10 wt%) than is currently used or with zinc oxide fillers. Field immersion tests were carried out in the Atlantic Ocean (Ste Anne du Portzic) and the Mediterranean Sea (Toulon), with contrasting physicochemical properties of water and macrofoulers' biodiversity. Microscopic analyses showed that AF coatings reduced the bacterial density differently for short immersion times at Ste Anne du Portzic. After four/five months of immersion, results, including multidimensional analyses, showed first specific patterns in the macrofoulers' assemblages depending on the site. In addition, the structure of macrofoulers' assemblages was affected by the biocide itself and by the combination of the biocide and the binder. When efficient, AF coatings appeared to decrease the richness with a strongest effect at Toulon. DCOIT was the most performing booster biocides whatever the immersion site and the polymer binder used. DCOIT was found to be efficient against marine bacteria and macrofoulers at Ste Anne du Portzic. The combination of zinc pyrithione with ZnO fillers in an aqueous-based AF paints exhibited the highest activity in the Mediterranean Sea over 16 months of immersion