Publications of Gilles Vandewalle
Bookmark and Share    
Full Text
See detailRepeatability of ultra-high-resolution Multi-Parametric Mapping across five 7T sites
Sherif, Siya ULiege; Aghaeifar, Ali; pine., Kerrin et al

Conference (2022)

Detailed reference viewed: 44 (2 ULiège)
Full Text
See detailENIGMA-Sleep: Challenges, opportunities, and the road map
Tahmasian, Masoud; Aleman, André; Andreassen, Ole A. et al

in Journal of Sleep Research (2021), e13347

Neuroimaging and genetics studies have advanced our understanding of the neurobiology of sleep and its disorders. However, individual studies usually have limitations to identifying consistent and ... [more ▼]

Neuroimaging and genetics studies have advanced our understanding of the neurobiology of sleep and its disorders. However, individual studies usually have limitations to identifying consistent and reproducible effects, including modest sample sizes, heterogeneous clinical characteristics and varied methodologies. These issues call for a large-scale multi-centre effort in sleep research, in order to increase the number of samples, and harmonize the methods of data collection, preprocessing and analysis using pre-registered well-established protocols. The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) consortium provides a powerful collaborative framework for combining datasets across individual sites. Recently, we have launched the ENIGMA-Sleep working group with the collaboration of several institutes from 15 countries to perform large-scale worldwide neuroimaging and genetics studies for better understanding the neurobiology of impaired sleep quality in population-based healthy individuals, the neural consequences of sleep deprivation, pathophysiology of sleep disorders, as well as neural correlates of sleep disturbances across various neuropsychiatric disorders. In this introductory review, we describe the details of our currently available datasets and our ongoing projects in the ENIGMA-Sleep group, and discuss both the potential challenges and opportunities of a collaborative initiative in sleep medicine. [less ▲]

Detailed reference viewed: 36 (3 ULiège)
Full Text
See detailTime course of cortical response complexity during extended wakefulness and its differential association with vigilance in young and older individuals
Gaggioni, Giulia ULiege; Shumbayawonda, Elizabeth; Montanaro, Umberto et al

in Biochemical Pharmacology (2021), epub ahead of print

Detailed reference viewed: 34 (10 ULiège)
Full Text
See detailCerebral functional networks during sleep in young and older individuals
Daneault, Véronique; Orban, Pierre; Martin, Nicolas et al

in Scientific Reports (2021), 11(1), 4905

Detailed reference viewed: 28 (4 ULiège)
Full Text
See detailBrain functional MRI responses to blue light stimulation in Leber’s hereditary optic neuropathy
Evangelisti, Stefania; La Morgia, Chiara; Testa, Claudia et al

in Biochemical Pharmacology (2021), epub ahead of print

Detailed reference viewed: 21 (6 ULiège)
Full Text
See detailVariability of sleep stage scoring in late midlife and early old age
Chylinski, Daphné ULiege; Berthomier, Christian; Lambot, Eric ULiege et al

in Journal of Sleep Research (2021)

Sleep stage scoring can lead to important inter-expert variability. Although likely, whether this issue is amplified in older populations, which show alterations of sleep electrophysiology, has not been ... [more ▼]

Sleep stage scoring can lead to important inter-expert variability. Although likely, whether this issue is amplified in older populations, which show alterations of sleep electrophysiology, has not been thoroughly assessed. Algorithms for automatic sleep stage scoring may appear ideal to eliminate inter-expert variability. Yet, variability between human experts and algorithm sleep stage scoring in healthy older individuals has not been investigated. Here, we aimed to compare stage scoring of older individuals and hypothesized that variability, whether between experts or considering the algorithm, would be higher than usually reported in the literature. Twenty cognitively normal and healthy late midlife individuals’ (61 ± 5 years; 10 women) night-time sleep recordings were scored by two experts from different research centres and one algorithm. We computed agreements for the entire night (percentage and Cohen's κ) and each sleep stage. Whole-night pairwise agreements were relatively low and ranged from 67% to 78% (κ, 0.54–0.67). Sensitivity across pairs of scorers proved lowest for stages N1 (8.2%–63.4%) and N3 (44.8%–99.3%). Significant differences between experts and/or algorithm were found for total sleep time, sleep efficiency, time spent in N1/N2/N3 and wake after sleep onset (p ≤ 0.005), but not for sleep onset latency, rapid eye movement (REM) and slow-wave sleep (SWS) duration (N2 + N3). Our results confirm high inter-expert variability in healthy aging. Consensus appears good for REM and SWS, considered as a whole. It seems more difficult for N3, potentially because human raters adapt their interpretation according to overall changes in sleep characteristics. Although the algorithm does not substantially reduce variability, it would favour time-efficient standardization. [less ▲]

Detailed reference viewed: 30 (3 ULiège)
Full Text
See detailPositive Effect of Cognitive Reserve on Episodic Memory, Executive and Attentional Functions Taking Into Account Amyloid-Beta, Tau, and Apolipoprotein E Status
Narbutas, Justinas ULiege; Chylinski, Daphné ULiege; Van Egroo, Maxime et al

in Frontiers in Aging Neuroscience (2021), 13

Studies exploring the simultaneous influence of several physiological and environmental factors on domain-specific cognition in late middle-age remain scarce. Therefore, our objective was to determine the ... [more ▼]

Studies exploring the simultaneous influence of several physiological and environmental factors on domain-specific cognition in late middle-age remain scarce. Therefore, our objective was to determine the respective contribution of modifiable risk/protective factors (cognitive reserve and allostatic load) on specific cognitive domains (episodic memory, executive functions, and attention), taking into account non-modifiable factors [sex, age, and genetic risk for Alzheimer’s disease (AD)] and AD-related biomarker amount (amyloid-beta and tau/neuroinflammation) in a healthy late-middle-aged population. One hundred and one healthy participants (59.4 ± 5 years; 68 women) were evaluated for episodic memory, executive and attentional functioning via neuropsychological test battery. Cognitive reserve was determined by the National Adult Reading Test. The allostatic load consisted of measures of lipid metabolism and sympathetic nervous system functioning. The amyloid-beta level was assessed using positron emission tomography in all participants, whereas tau/neuroinflammation positron emission tomography scans and apolipoprotein E genotype were available for 58 participants. Higher cognitive reserve was the main correlate of better cognitive performance across all domains. Moreover, age was negatively associated with attentional functioning, whereas sex was a significant predictor for episodic memory, with women having better performance than men. Finally, our results did not show clear significant associations between performance over any cognitive domain and apolipoprotein E genotype and AD biomarkers. This suggests that domain-specific cognition in late healthy midlife is mainly determined by a combination of modifiable (cognitive reserve) and non-modifiable factors (sex and age) rather than by AD biomarkers and genetic risk for AD. [less ▲]

Detailed reference viewed: 51 (9 ULiège)
Full Text
See detailAssociations between cognitive complaints, memory performance, mood and amyloid-β accumulation in healthy amyloid negative late-midlife individuals
Narbutas, Justinas ULiege; Van Egroo, Maxime; Chylinski, Daphné ULiege et al

in Journal of Alzheimer's Disease (2021), 83

Background. Cognitive complaints are gaining more attention as they may represent an early marker of increased risk for AD in individuals without objective decline at standard neuropsychological ... [more ▼]

Background. Cognitive complaints are gaining more attention as they may represent an early marker of increased risk for AD in individuals without objective decline at standard neuropsychological examination. Objective. Our aim was to assess whether cognitive complaints in late middle-aged individuals not seeking medical help are related to objective cognitive outcomes known as early markers for AD risk, concomitant affective state, and amyloid-β (Aβ) burden. Methods. Eighty-seven community-based cognitively normal individuals aged 50-69 years underwent neuropsychological assessment for global cognition, using Preclinical Alzheimer’s Cognitive Composite 5 (PACC5) score, and a more specific episodic memory measure. Affective state was based on self-assessment questionnaires for depression and anxiety. Aβ PET burden was assessed via [18F]Flutemetamol (N=84) and [18F]Florbetapir (N=3) uptake. Cognitive complaints were evaluated using Cognitive Difficulties Scale. Results. Higher cognitive complaints were significantly associated with lower episodic memory performance and worse affective state. Moreover, higher level of cognitive complaints was related to higher (but still sub-clinical) global Aβ accumulation (at uncorrected significance level). Importantly, all three aspects remained significant when taken together in the same statistical model, indicating that they explained distinct parts of variance. Conclusion. In healthy Aβ negative late middle-aged individuals, a higher degree of cognitive complaints is associated with lower episodic memory efficiency, more anxiety and depression, as well as, potentially, with higher Aβ burden, suggesting that complaints might signal subtle decline. Future studies should untangle how cognitive complaints in healthy aging populations are related to longitudinal changes in objective cognition and AD biomarker correlates. [less ▲]

Detailed reference viewed: 61 (6 ULiège)
Full Text
See detailHeterogeneity in the links between sleep arousals, amyloid-beta and cognition
Chylinski, Daphné ULiege; Van Egroo, Maxime; Narbutas, Justinas ULiege et al

in JCI Insight (2021)

BACKGROUND. Tight relationships between sleep quality, cognition and amyloid-beta (Aβ) accumulation, a hallmark of Alzheimer’s disease (AD) neuropathology, emerge in the literature. Sleep arousals become ... [more ▼]

BACKGROUND. Tight relationships between sleep quality, cognition and amyloid-beta (Aβ) accumulation, a hallmark of Alzheimer’s disease (AD) neuropathology, emerge in the literature. Sleep arousals become more prevalent with ageing and are considered to reflect poorer sleep quality. Yet, heterogeneity in arousals has been suggested while their associations with Aβ and cognition are not established. METHODS. We recorded undisturbed night-time sleep with EEG in 101 healthy individuals in late midlife (50-70y), devoid of cognitive and sleep disorders. We classified spontaneous arousals according to their association with muscular tone increase (M+/M-) and sleep stage transition (T+/T-). We assessed cortical Aβ burden over earliest affected regions via PET imaging, and cognition via extensive neuropsychological testing. RESULTS. Arousal types differed in their oscillatory composition in theta and beta EEG bands. Furthermore, T+M- arousals, which interrupt sleep continuity, were positively linked to Aβ burden (p=.0053, R²β*=0.08). By contrast, more prevalent T-M+ arousals, upholding sleep continuity, were associated with lower Aβ burden (p=.0003, R²β*=0.13), and better cognition, particularly over the attentional domain (p<.05, R²β*≥0.04). CONCLUSION. Contrasting with what is commonly accepted, we provide empirical evidence that arousals are diverse and differently associated with early AD-related neuropathology and cognition. This suggests that sleep arousals, and their coalescence with other brain oscillations during sleep, may actively contribute to the beneficial functions of sleep. This warrants re-evaluation of age-related sleep changes and suggests that spontaneous arousals could constitute a marker of favourable brain and cognitive health trajectories. [less ▲]

Detailed reference viewed: 28 (4 ULiège)
Full Text
See detailChanges in EEG Permutation Entropy in the evening and in the transition from wake to sleep
Hou, Fengzhen; Zhang, Lulu; Qin, Baokun et al

in Sleep (2020), 44

Detailed reference viewed: 28 (6 ULiège)
Full Text
See detailAssociation between sleep regulation and neuroimaging-derived myelin markers
Deantoni, Michele ULiege; Muto, Vincenzo ULiege; Hammad, Grégory ULiege et al

Conference (2020, September 22)

Introduction Sleep plays a crucial role in brain plasticity, and has been suggested to be involved in myelin organization. Here we assessed the association between sleep homeostatic responses and ... [more ▼]

Introduction Sleep plays a crucial role in brain plasticity, and has been suggested to be involved in myelin organization. Here we assessed the association between sleep homeostatic responses and quantitative MRI-derived myelin content in a sample of healthy young men. Methods: 238 male participants (age: 22.12.7) underwent an in-lab protocol to assess homeostatic responses in slow wave and REM sleep through a modulation of prior wakefulness and sleep duration. The protocol encompassed four conditions: a baseline night (BAS, duration adjusted on participant’s sleep-wake schedule), a 12h sleep extension night (EXT) followed by a 4-h nap and an 8-h sleep opportunity night (sleep saturation; SAT) and a 12h recovery night (REC) following 40-hours sleep deprivation. For each night, four sleep parameters were extracted: sleep slow wave activity at the beginning of the night (SWA0), its overnight exponential dissipation rate (tau), and overnight mean theta and beta power per REM epoch. Participants underwent a multiparameter brain MRI protocol at 3T to extract quantitative maps sensitive to different myelin biomarkers. F-contrasts were calculated to assess whether the modularity of sleep parameters across sleep conditions explains variance in myelin biomarkers. Reported statistics are family-wise-error corrected over the entire brain volume (pFWE <.05). Results: Slow wave sleep duration and SWA0 were modulated across all sleep conditions (REC>BAS>EXT>SAT; all p < 0.001), while REM sleep percentage significantly differed only between SAT and the other sleep contexts (F(3,1257)= 13.676743, p<.001). The modulation of NREM SWA0 was associated with myelin content in the medio-temporal lobe, encompassing the bilateral hippocampus and entorhinal cortex (grey and white matter), while the modulation of REM beta power was associated to myelin content in diffuse thalamocortical tracts and overhead cortices. Discussion: Spectral power in sleep-specific frequency bands across sleep homeostasis contexts is associated with myelin content in the hippocampus and surrounding cortices as well as thalamocortical fibers. The hippocampus has been proposed as a key player for temporal coupling of brain oscillations, while thalamocortical fibers myelination may facilitate the cortical response to sleep-dependent diencephalic activity. As myelin stands for conduction velocity, it could facilitate the modulation of brain electrical oscillations, and putatively also the homeostatic response of sleep. [less ▲]

Detailed reference viewed: 68 (2 ULiège)
Full Text
See detailIncreased cortical excitability but stable effective connectivity index during attentional lapses.
Cardone, Paolo ULiege; Van Egroo, Maxime ULiege; Chylinski, Daphné ULiege et al

in Sleep (2020)

Modern lifestyle curtails sleep and increases night-time work and leisure activities. This has a deleterious impact on vigilance and attention, exacerbating chances of committing attentional lapses, with ... [more ▼]

Modern lifestyle curtails sleep and increases night-time work and leisure activities. This has a deleterious impact on vigilance and attention, exacerbating chances of committing attentional lapses, with potential dramatic outcomes. Here, we investigated the brain signature of attentional lapses and assessed whether cortical excitability and brain response propagation were modified during lapses and whether these modifications changed with aging. We compared electroencephalogram (EEG) responses to transcranial magnetic stimulation (TMS) during lapse and no-lapse periods while performing a continuous attentional/vigilance task at night, after usual bedtime. Data were collected in healthy younger (N=12; 18-30 y) and older individuals (N=12; 50-70 y) of both sexes. The amplitude and slope of the first component of the TMS-Evoked Potential (TEP) were larger during lapses. In contrast, TMS response scattering over the cortical surface, as well as EEG response complexity, did not significantly vary between lapse and no-lapse periods. Importantly, despite qualitative differences, age did not significantly affect any of the TMS-EEG measures. These results demonstrate that attentional lapses are associated with a transient increase of cortical excitability. This initial change is not associated with detectable changes in subsequent effective connectivity - as indexed by response propagation - and are not markedly different between younger and older adults. These findings could contribute to develop models aimed to predicting and preventing lapses in real life situations. [less ▲]

Detailed reference viewed: 54 (11 ULiège)
Full Text
See detailExploring scoring methods for research studies: Accuracy and variability of visual and automated sleep scoring
Berthomier, Christian; Muto, Vincenzo ULiege; Schmidt, Christina ULiege et al

in Journal of Sleep Research (2020)

Sleep studies face new challenges in terms of data, objectives and metrics. This requires reappraising the adequacy of existing analysis methods, including scoring methods. Visual and automatic sleep ... [more ▼]

Sleep studies face new challenges in terms of data, objectives and metrics. This requires reappraising the adequacy of existing analysis methods, including scoring methods. Visual and automatic sleep scoring of healthy individuals were compared in terms of reliability (i.e., accuracy and stability) to find a scoring method capable of giving access to the actual data variability without adding exogenous variability. A first dataset (DS1, four recordings) scored by six experts plus an autoscoring al-gorithm was used to characterize inter-scoring variability. A second dataset (DS2, 88 recordings) scored a few weeks later was used to explore intra-expert variabil-ity. Percentage agreements and Conger's kappa were derived from epoch-by-epoch comparisons on pairwise and consensus scorings. On DS1 the number of epochs of agreement decreased when the number of experts increased, ranging from 86% (pairwise) to 69% (all experts). Adding autoscoring to visual scorings changed the kappa value from 0.81 to 0.79. Agreement between expert consensus and autoscor-ing was 93%. On DS2 the hypothesis of intra-expert variability was supported by a systematic decrease in kappa scores between autoscoring used as reference and each single expert between datasets (.75–.70). Although visual scoring induces inter- and intra-expert variability, autoscoring methods can cope with intra-scorer variabil-ity, making them a sensible option to reduce exogenous variability and give access to the endogenous variability in the data. [less ▲]

Detailed reference viewed: 113 (22 ULiège)
Full Text
See detailCognitive efficiency in late midlife is linked to lifestyle characteristics and allostatic load
Narbutas, Justinas ULiege; Van Egroo, Maxime ULiege; Chylinski, Daphné ULiege et al

in Aging (2019), 11

We investigated whether cognitive fitness in late midlife is associated with physiological and psychological factors linked to increased risk of age-related cognitive decline. Eighty-one healthy late ... [more ▼]

We investigated whether cognitive fitness in late midlife is associated with physiological and psychological factors linked to increased risk of age-related cognitive decline. Eighty-one healthy late middle-aged participants (mean age: 59.4 y; range: 50-69 y) were included. Cognitive fitness consisted of a composite score known to be sensitive to early subtle cognitive change. Lifestyle factors (referenced below as cognitive reserve factors; CRF) and affective state were determined through questionnaires, and sleep-wake quality was also assessed through actimetry. Allostatic load (AL) was determined through a large range of objective health measures. Generalized linear mixed models, controlling for sex and age, revealed that higher cognitive reserve and lower allostatic load are related to better cognitive efficiency. Crystallized intelligence, sympathetic nervous system functioning and lipid metabolism were the only sub-fields of CRF and AL to be significantly associated with cognition. These results show that previous lifestyle characteristics and current physiological status are simultaneously explaining variability in cognitive abilities in late midlife. Results further encourage early multimodal prevention programs acting on both of these modifiable factors to preserve cognition during the aging process. [less ▲]

Detailed reference viewed: 145 (55 ULiège)
Full Text
See detailPreserved wake-dependent cortical excitability dynamics predict cognitive fitness beyond age-related brain alterations.
Van Egroo, Maxime ULiege; Narbutas, Justinas ULiege; Chylinski, Daphné ULiege et al

in Communications Biology (2019), 2

Age-related cognitive decline arises from alterations in brain structure as well as in sleep-wake regulation. Here, we investigated whether preserved wake-dependent regulation of cortical function could ... [more ▼]

Age-related cognitive decline arises from alterations in brain structure as well as in sleep-wake regulation. Here, we investigated whether preserved wake-dependent regulation of cortical function could represent a positive factor for cognitive fitness in aging. We quantified cortical excitability dynamics during prolonged wakefulness as a sensitive marker of age-related alteration in sleep-wake regulation in 60 healthy older individuals (50-69 y; 42 women). Brain structural integrity was assessed with amyloid-beta- and tau-PET, and with MRI. Participants' cognition was investigated using an extensive neuropsychological task battery. We show that individuals with preserved wake-dependent cortical excitability dynamics exhibit better cognitive performance, particularly in the executive domain which is essential to successful cognitive aging. Critically, this association remained significant after accounting for brain structural integrity measures. Preserved dynamics of basic brain function during wakefulness could therefore be essential to cognitive fitness in aging, independently from age-related brain structural modifications that can ultimately lead to dementia. [less ▲]

Detailed reference viewed: 177 (29 ULiège)