References of "Schmidt, Christina"
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See detailAging reduces the circadian modulation of cortical reactivity during sleep loss and modifies its link with cognition
Gaggioni, Giulia ULiege; Ly, Julien; Muto, Vincenzo ULiege et al

in Neurobiology of Aging (2019), in press

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See detailLa sieste comme indice de fragmentation du cycle de veille-sommeil : impact sur la cognition
Reyt, Mathilde ULiege; Latteur, Alizée; Schmidt, Christina ULiege et al

Conference (2018, November 23)

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See detailLes horloges biologiques
Schmidt, Christina ULiege

Conference given outside the academic context (2018)

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See detailSleep fragmentation is associated with brain tau but not amyloid-β burden in healthy older adults
Chylinski, Daphné ULiege; Rudzik, Franziska; Coppieters't Wallant, Dorothe ULiege et al

Conference (2018, November 09)

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See detailArousals during sleep are associated with brain tau burden in healthy older individuals
Chylinski, Daphné ULiege; Rudzik, Franziska; Coppieters't Wallant, Dorothe ULiege et al

Poster (2018, October 19)

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See detailImpact of age and napping on actimetry-derived sleep and 24-h rest-activity indices
Reyt, Mathilde ULiege; Latteur, Alizée; Maire, Micheline et al

Poster (2018, September 26)

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See detailNew spectral analysis method to identify trait-like features in NREM sleep power spectra
Hammad, Grégory ULiege; Muto, Vincenzo ULiege; Gaggioni, Giulia ULiege et al

Conference (2018, September 26)

Introduction: Variability among individuals in sleep/wake biology and behaviour is pervasive. Sleep/wake-related variability involves individual trait-like features (ITLF). In order to study ITLF, we ... [more ▼]

Introduction: Variability among individuals in sleep/wake biology and behaviour is pervasive. Sleep/wake-related variability involves individual trait-like features (ITLF). In order to study ITLF, we developed an advanced spectral analysis method (ASAM) to compare in a systematic and reproducible way 3 features of NREM power spectra (PS). As sleep spindles (SS) have been reported several times to be an important ITLF, we focused on a broad range of sigma activity (10 − 18Hz). Methods: The ASAM is composed of three main steps. First, EEG sleep recording is preprocessed and the NREM PS is computed for each channel of interest. Second, three characteristic features from the NREM PS related to sigma peak activity are extracted: magnitude, peak location and standard deviation. Third, the intra-individual stability and the inter-individual variability of these features, as well as the influence of sleep perturbations, are statistically tested using the Intra-Class Correlation (ICC) coefficient and the Wald Z-test. The performance of the ASAM was assessed using different polysomnography-derived sleep recordings from 16 healthy young male subjects (18-30 years). For each subject, these recordings were acquired in 5 different “sleep contexts”: the acquisition was varied from 4h to 12h and was performed at different circadian phases. Results: All three features of sigma activity (magnitude, peak location and its standard deviation) were recognized as important ITLFs (ICC = 0.74, 0.94 and 0.63 respectively). Furthermore, the inter-individual variability of these three features was significant different from zero (Wald Z-test ps < 0.05). Conclusion: Three aspects of NREM PS sigma activity are recognized as important ITLFs. It is also showed that even though these features changed according to sleep context, they remained specific to the individuals. Establishing the trait-specific nature of variability in sleep/wake parameters could elucidate genetic mechanisms. [less ▲]

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See detailAge-related changes in circadian sleep-wake regulation: Impact on cognitive performance and cerebral correlates
Schmidt, Christina ULiege; Reichert, Carolin; Deantoni, Michele ULiege et al

in Journal of Sleep Research. Supplement (2018, September 26)

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See detailTemporal constraints on sleep and cognition: importance for brain health during ageing
Schmidt, Christina ULiege

Conference (2018, September 26)

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See detailInter- and intra-expert variability in sleep scoring: comparison between visual and automatic analysis
Muto, Vincenzo ULiege; Berthomier, Christian; Schmidt, Christina ULiege et al

in Journal of Sleep Research. Supplement (2018, September 11)

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See detailAssociation of circadian sleep-wake regulation and brain structure in older adults: a multi-modal approach
Deantoni, Michele ULiege; Hammad, Grégory ULiege; Maire, Micheline et al

Conference (2018, September)

Introduction: The temporal organization of sleep and wakefulness evolves throughout the lifespan, leading to an increased sleep-wake fragmentation with ageing. However, how circadian aspects of sleep-wake ... [more ▼]

Introduction: The temporal organization of sleep and wakefulness evolves throughout the lifespan, leading to an increased sleep-wake fragmentation with ageing. However, how circadian aspects of sleep-wake regulation relate to brain structure during ageing is not known. We aimed at exploring whether grey matter volume and surface measures are associated to an electrophysiology-derived index of circadian sleep-wake regulation. Methods: Eleven older participants (55-75 years; 7 men) underwent a 40-h multiple nap protocol encompassing 10 nap periods. Nap sleep efficiency over the circadian cycle was obtained with polysomnography and used as an index of circadian sleep-wake promotion. The difference between the sleep ability during the night and day sleep, here called circadian sleep amplitude (CSA) was taken as an indicator of circadian integrity. T1-weighted brain scans were analysed with two complementary approaches: Voxel-Based Morphometry (VBM) to extract total grey matter volume, and Surface-Based Morphometry to extract total cortical thickness. Results: Contrary to our hypothesis, a correlation analysis revealed that grey matter volume was negatively associated with CSA (r2= 0.385, p= 0.042), while cortical thickness was not significantly correlated. Remarkably, grey matter volume was also negatively associated with cortical thickness (r2= 0.454, p= 0.023). Since VBM fails to properly detect folding structures inside the brain, we calculated the local gyrification index for each participant using a surface-based morphometry approach. We observed that the mean of local gyrification indices across the brain showed a trend for a positive correlation with CSA (r2= 0.324, p= 0.067). Conclusions: Despite the small sample size, our data suggest that a less folded brain has more “visible” grey matter detectable with the VBM approach, explaining the negative link between grey matter volume and cortical thickness but also with CSA. The results highlight the necessity of analysing surface indices in addition to volumetry. Within this context, our data suggest that a more “folded” brain, an index of brain fitness at older age, is associated with circadian integrity and should be considered in models linking sleep-wake regulation to brain ageing. Future region-based analyses of brain surface indices will be performed. Disclosures of potential conflict of interest: the authors do not disclose a potential conflict of interest [less ▲]

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See detailArousals during sleep are associated with brain tau and amyloid-β burden in healthy older adults
Chylinski, Daphné ULiege; Rudzik, Franziska; Coppieters't Wallant, Dorothe ULiege et al

Conference (2018, September)

Detailed reference viewed: 66 (26 ULiège)