Publications

Berthomier C., Electroencéphalogramme, retour vers le futur ? Une mesure de la charge cognitive par EEG bientôt sur le terrain. Le Magazine des ingénieurs de l’armement – n°131 – Facteur humain, mars 2024

> Accéder à l’article complet Electroencéphalogramme, retour vers le futur ? Une mesure de la charge cognitive par EEG bientôt sur le terrain

Muto V. & Berthomier C., Looking for a balance between visual and automatic sleep scoring, NPJ Digit Med. 2023 Sep 5;6(1):165. doi: 10.1038/s41746-023-00915-7. PMID: 37670135; PMCID: PMC10480143.

> Accéder à l’article Looking for a balance between visual and automatic sleep scoring.

Berthomier C, Brandewinder M, Sleep scoring: man vs. machine ?, Sleep Breath. 17 (2):461-462, 2013

The automated analysis of sleep has grown in interest in the past decade. Advances in computing have brought the needed intensive calculations within reach; while simultaneously, there is an increasing demand for sleep diagnosis and analysis. The prevalence of sleep troubles is high, and the awareness of their consequences is spreading among patients, health authorities, and clinicians. This awareness is directing more and more patients to sleep centers. The upward trend in demand for sleep evaluations concerns not only sleep specialists. Sleep appears to be an extremely promising territory for other fields, such as cardiology and nutrition for example. Needs exceed capacities by this far. Data analysis has been identified as one of the bottlenecks in the sleep evaluation process, making clear the importance of developing tools to facilitate analysis. These developments have an impact that is medical, as well as economical and social.

 
>Accéder à l’article complet : Sleep scoring: man vs. machine ?

Tankéré P, Taillard J, Stauffer E, Petitjean T, Berthomier C, Strauss M, Tamisier R, Peter-Derex L. Phenotyping patients treated for obstructive sleep apnea with persistent objective impaired alertness or subjective sleepiness. Sleep Med. 2024 Oct;122:221-229. doi: 10.1016/j.sleep.2024.08.001. Epub 2024 Aug 23. PMID: 39208521.

> Abstract Phenotyping patients treated for obstructive sleep apnea with persistent objective impaired alertness or subjective sleepiness

F. Gobert, I. Merida, E. Maby, P. Seguin, J. Jung, D. Morlet, N. André-Obadia, F. Dailler, Ch. Berthomier, A. Otman, D. Le Bars, Ch. Scheiber, A. Hammers, E. Bernard, N. Costes, R. Bouet, J. Mattout. A disorder of consciousness rather than complete locked-in may be the final stage of ALS. medRxiv 2024.06.21.24307994; doi: https://doi.org/10.1101/2024.06.21.24307994

> Article A disorder of consciousness rather than complete locked-in may be the final stage of ALS

Deantoni M, Reyt M, Dourte M, de Haan S, Lesoinne A, Vandewalle G, Phillips C, Berthomier C, Maquet P, Muto V, Hammad G, Schmidt C, Baillet M. Circadian rapid eye movement sleep expression is associated with brain microstructural integrity in older adults. Commun Biol. 2024 Jun 22;7(1):758. doi: 10.1038/s42003-024-06415-y. PMID: 38909162; PMCID: PMC11193799.

> Abstract Circadian rapid eye movement sleep expression is associated with brain microstructural integrity in older adults

Billat, V.; Berthomier, C.; Clémençon, M.; Brandewinder, M.; Essid, S.; Damon, C.; Rigaud, F.; Bénichoux, A.; Maby, E.; Fornoni, L.; et al. Electroencephalography Response during an Incremental Test According to the V̇O2max Plateau Incidence. Appl. Sci. 2024, 14, 5411. https://doi.org/10.3390/app14135411

> Abstract Electroencephalography Response during an Incremental Test According to the V̇O2max Plateau Incidence

REM sleep quality is associated with balanced tonic activity of the locus coeruleus during wakefulness. N Mortazavi, P Talwar, E Koshmanova, R Sharifpour, E Beckers, A Berger, et al. bioRxiv, 2024.07. 12.603275

> Abstract REM sleep quality is associated with balanced tonic activity of the locus coeruleus during wakefulness

F Palacin, L Poinsard, J Mattei, C Berthomier, V Billat, Brain, Metabolic, and RPE Responses during a Free-Pace Marathon: A Preliminary Study, International Journal of Environmental Research and Public Health 21 (8), 1024

> Article Brain, Metabolic, and RPE Responses during a Free-Pace Marathon: A Preliminary Study

P Tankéré, J Taillard, T Petitjean, C Berthomier, M Strauss, LP Derex, Somnolence diurne excessive et SAHOS traité: facteurs prédictifs des tests de maintien d’éveil, Médecine du Sommeil 21 (1), 22

> Abstract Somnolence diurne excessive et SAHOS traité: facteurs prédictifs des tests de maintien d’éveil

Deantoni M, Reyt M, Baillet M, Dourte M, De Haan S, Lesoinne A, Vandewalle G, Maquet P, Berthomier C, Muto V, Hammad G, Schmidt C. Napping and circadian sleep-wake regulation during healthy aging. Sleep. 2024 May 10;47(5):zsad287. doi: 10.1093/sleep/zsad287. PMID: 37943833.

> Abstract Napping and circadian sleep-wake regulation during healthy aging.

Sadoc M, Clairembault T, Coron E, Berthomier C, Le Dily S, Vavasseur F, Pavageau A, St Louis EK, Péréon Y, Neunlist M, Derkinderen P, Leclair-Visonneau L. Wake and non-rapid eye movement sleep dysfunction is associated with colonic neuropathology in Parkinson’s disease. Sleep. 2024 Mar 11;47(3):zsad310. doi: 10.1093/sleep/zsad310. PMID: 38156524.

> Texte complet Wake and non-rapid eye movement sleep dysfunction is associated with colonic neuropathology in Parkinson’s disease.

Talwar P, Deantoni M, Van Egroo M, Muto V, Chylinski D, Koshmanova E, Jaspar M, Meyer C, Degueldre C, Berthomier C, Luxen A, Salmon E, Collette F, Dijk DJ, Schmidt C, Phillips C, Maquet P, Sherif S, Vandewalle G. Author Correction: In vivo marker of brainstem myelin is associated to quantitative sleep parameters in healthy young men. Sci Rep. 2024 Mar 13;14(1):6124. doi: 10.1038/s41598-024-56474-8. Erratum for: Sci Rep. 2023 Nov 27;13(1):20873. doi: 10.1038/s41598-023-47753-x. PMID: 38480866; PMCID: PMC10937964.

> Abstract Author Correction: In vivo marker of brainstem myelin is associated to quantitative sleep parameters in healthy young men

Cajochen C, Reichert CF, Münch M, Gabel V, Stefani O, Chellappa SL, Schmidt C. Ultradian sleep cycles: Frequency, duration, and associations with individual and environmental factors-A retrospective study. Sleep Health. 2024 Feb;10(1S):S52-S62. doi: 10.1016/j.sleh.2023.09.002. Epub 2023 Oct 31. PMID: 37914631.

> Article Ultradian sleep cycles: Frequency, duration, and associations with individual and environmental factors-A retrospective study

Talwar P, Deantoni M, Van Egroo M, Muto V, Chylinski D, Koshmanova E, Jaspar M, Meyer C, Degueldre C, Berthomier C, Luxen A, Salmon E, Collette F, Dijk DJ, Schmidt C, Phillips C, Maquet P, Sherif S, Vandewalle G. In vivo marker of brainstem myelin is associated to quantitative sleep parameters in healthy young men. Sci Rep. 2023 Nov 27;13(1):20873. doi: 10.1038/s41598-023-47753-x. Erratum in: Sci Rep. 2024 Mar 13;14(1):6124. doi: 10.1038/s41598-024-56474-8. PMID: 38012207; PMCID: PMC10682495.

> Abstract In vivo marker of brainstem myelin is associated to quantitative sleep parameters in healthy young men

Gobert F, Corneyllie A, Bastuji H, Berthomier C, Thevenet M, Abernot J, Raverot V, Dailler F, Guérin C, Gronfier C, Luauté J, Perrin F. Twenty-four-hour rhythmicities in disorders of consciousness are associated with a favourable outcome. Commun Biol. 2023 Nov 29;6(1):1213. doi: 10.1038/s42003-023-05588-2. PMID: 38030756; PMCID: PMC10687012.

> Texte complet Twenty-four-hour rhythmicities in disorders of consciousness are associated with a favourable outcome.

Deantoni M, Reyt M, Baillet M, Dourte M, De Haan S, Lesoinne A, Vandewalle G, Maquet P, Berthomier C, Muto V, Hammad G, Schmidt C. Napping and circadian sleep-wake regulation during healthy aging. Sleep. 2023 Nov 7:zsad287. doi: 10.1093/sleep/zsad287. Epub ahead of print. PMID: 37943833.

> Texte complet Napping and circadian sleep-wake regulation during healthy aging.

Deantoni M, Reyt M, Berthomier C, Muto V, Hammad G, De Haan S, Dourte M, Taillard J, Lambot E, Cajochen C, Reichert CF, Maire M, Baillet M, Schmidt C. Association between circadian sleep regulation and cortical gyrification in young and older adults. Sleep. 2023 Sep 8;46(9):zsad094. doi: 10.1093/sleep/zsad094. PMID: 37010079.

> Texte complet Association between circadian sleep regulation and cortical gyrification in young and older adults.

Koshmanova E, Berger A, Beckers E, Campbell I, Mortazavi N, Sharifpour R, Paparella I, Balda F, Berthomier C, Degueldre C, Salmon E, Lamalle L, Bastin C, Van Egroo M, Phillips C, Maquet P, Collette F, Muto V, Chylinski D, Jacobs HI, Talwar P, Sherif S, Vandewalle G. Locus coeruleus activity while awake is associated with REM sleep quality in older individuals. JCI Insight. 2023 Oct 23;8(20):e172008. doi: 10.1172/jci.insight.172008. PMID: 37698926; PMCID: PMC10619502.

> Texte complet Locus coeruleus activity while awake is associated with REM sleep quality in older individuals.

Deantoni M, Baillet M, Hammad G, Berthomier C, Reyt M, Jaspar M, Meyer C, Van Egroo M, Talwar P, Lambot E, Chellappa SL, Degueldre C, Luxen A, Salmon E, Balteau E, Phillips C, Dijk DJ, Vandewalle G, Collette F, Maquet P, Muto V, Schmidt C. Association between sleep slow-wave activity and in-vivo estimates of myelin in healthy young men. Neuroimage. 2023 May 15;272:120045. doi: 10.1016/j.neuroimage.2023.120045. Epub 2023 Mar 29. PMID: 36997136; PMCID: PMC10112274.

> Texte complet Association between sleep slow-wave activity and in-vivo estimates of myelin in healthy young men. 

André C, Champetier P, Rehel S, Kuhn E, Touron E, Ourry V, Landeau B, Le Du G, Mézenge F, Segobin S, de la Sayette V, Vivien D, Chételat G, Rauchs G; Medit-Ageing Research Group. Rapid Eye Movement Sleep, Neurodegeneration, and Amyloid Deposition in Aging. Ann Neurol. 2023 May;93(5):979-990. doi: 10.1002/ana.26604. Epub 2023 Jan 27. PMID: 36641644.

> Texte complet Rapid Eye Movement Sleep, Neurodegeneration, and Amyloid Deposition in Aging.

Scott L, Puryear CB, Belfort GM, Raines S, Hughes ZA, Matthews LG, Ravina B, Wittmann M. Translational Pharmacology of PRAX-944, a Novel T-Type Calcium Channel Blocker in Development for the Treatment of Essential Tremor. Mov Disord. 2022 Jun;37(6):1193-1201. doi: 10.1002/mds.28969. Epub 2022 Mar 7. PMID: 35257414; PMCID: PMC9310641.

> Accéder à l’article Translational Pharmacology of PRAX-944, a Novel T-Type Calcium Channel Blocker in Development for the Treatment of Essential Tremor

Koshmanova E, Muto V, Chylinski D, Mouraux C, Reyt M, Grinard M, Talwar P, Lambot E, Berthomier C, Brandewinder M, Mortazavi N, Degueldre C, Luxen A, Salmon E, Georges M, Collette F, Maquet P, Van Someren E, Vandewalle G. Genetic risk for insomnia is associated with objective sleep measures in young and healthy good sleepers. Neurobiol Dis. 2022 Nov 9:105924. doi: 10.1016/j.nbd.2022.105924. Epub ahead of print. PMID: 36371058.

> Accéder à l’article Genetic risk for insomnia is associated with objective sleep measures in young and healthy good sleepers.

> Accéder à l’article Sleep-dependent memory consolidation in breast cancer: Use of a virtual reality prospective memory task.

> Accéder à l’article Frontal grey matter microstructure is associated with sleep slow waves characteristics in late midlife. 

Chylinski D, Van Egroo M, Narbutas J, Muto V, Bahri MA, Berthomier C, Salmon E, Bastin C, Phillips C, Collette F, Maquet P, Carrier J, Lina JM, Vandewalle G. Timely coupling of sleep spindles and slow waves linked to early amyloid-β burden and predicts memory decline. Elife. 2022 May 31;11:e78191. doi: 10.7554/eLife.78191. PMID: 35638265..

> Accéder à l’article Timely coupling of sleep spindles and slow waves linked to early amyloid-β burden and predicts memory decline

Analyse de l’électroencéphalogramme (EEG) de l’éveil et du sommeil chez l’homme–Monitoring EEG de gestion veille-sommeil, C Berthomier & M Brandewinder, Médecine du Sommeil, Elsevier, 2021

> Accéder à l’article Analyse de l’électroencéphalogramme (EEG) de l’éveil et du sommeil chez l’homme–Monitoring EEG de gestion veille-sommeil

Daphne O. Chylinski, Maxime Van Egroo, Justinas Narbutas, Martin Grignard, Ekaterina Koshmanova, Christian Berthomier, Pierre Berthomier, Marie Brandewinder, Eric Salmon, Mohamed Ali Bahri, Christine Bastin, Fabienne Collette, Christophe Phillips, Pierre Maquet, Vincenzo Muto, and Gilles Vandewalle. Heterogeneity in the links between sleep arousals, amyloid-β, and cognition. JCI Insight. 2021;6(24):e152858. https://doi.org/10.1172/jci.insight.152858.

> Accéder à l’article Heterogeneity in the links between sleep arousals, amyloid-β, and cognition

Sleep parameters improvement in PTSD soldiers after symptoms remission. Rousseau, P. F., Vallat, R., Coste, O., Cadis, H., Nicolas, F., Trousselard, M., Ruby P. & Khalfa, S. Scientific reports, 11(1), 1-13.

Muto V, Koshmanova E, Ghaemmaghami P, Jaspar M, Meyer C, Elansary M, Van Egroo M, Chylinski D, Berthomier C, Brandewinder M, Mouraux C, Schmidt C, Hammad G, Coppieters W, Ahariz N, Degueldre C, Luxen A, Salmon E, Phillips C, Archer SN, Yengo L, Byrne E, Collette F, Georges M, Dijk DJ, Maquet P, Visscher PM, Vandewalle G. Alzheimer’s disease genetic risk and sleep phenotypes in healthy young men: association with more slow waves and daytime sleepiness. Sleep. 2021 Jan 21;44(1):zsaa137. doi: 10.1093/sleep/zsaa137. PMID: 32671396.

Study objectives: Sleep disturbances and genetic variants have been identified as risk factors for Alzheimer’s disease (AD). Our goal was to assess whether genome-wide polygenic risk scores (PRS) for AD associate with sleep phenotypes in young adults, decades before typical AD symptom onset.

Methods: We computed whole-genome PRS for AD and extensively phenotyped sleep under different sleep conditions, including baseline sleep, recovery sleep following sleep deprivation, and extended sleep opportunity, in a carefully selected homogenous sample of 363 healthy young men (22.1 years ± 2.7) devoid of sleep and cognitive disorders.

Results: AD PRS was associated with more slow-wave energy, that is, the cumulated power in the 0.5-4 Hz EEG band, a marker of sleep need, during habitual sleep and following sleep loss, and potentially with larger slow-wave sleep rebound following sleep deprivation. Furthermore, higher AD PRS was correlated with higher habitual daytime sleepiness.

Conclusions: These results imply that sleep features may be associated with AD liability in young adults, when current AD biomarkers are typically negative, and support the notion that quantifying sleep alterations may be useful in assessing the risk for developing AD.

> Accéder à l’article Alzheimer’s disease genetic risk and sleep phenotypes in healthy young men: association with more slow waves and daytime sleepiness

Giulia Gaggioni, Julien Q.M. Ly, Vincenzo Muto, Sarah L. Chellappa, Mathieu Jaspar, Christelle Meyer, Tillo Delfosse, Amaury Vanvinckenroye, Romain Dumont, Dorothée Coppieters ‘t Wallant, Christian Berthomier, Justinas Narbutas, Maxime Van Egroo, Andé Luxen, Eric Salmon, Fabienne Collette, Christophe Phillips, ChristinanSchmidt, Gilles Vandewalle, Age-related decrease in cortical excitability circadian variations during sleep loss and its links with cognition, Neurobiology of Aging 2019; 78, 52-63

Cortical excitability depends on sleep-wake regulation, is central to cognition, and has been implicated in age-related cognitive decline. The dynamics of cortical excitability during prolonged wakefulness in aging are unknown, however. Here, we repeatedly probed cortical excitability of the frontal cortex using transcranial magnetic stimulation and electroencephalography in 13 young and 12 older healthy participants during sleep deprivation. Although overall cortical excitability did not differ between age groups, the magnitude of cortical excitability variations during prolonged wakefulness was dampened in older individuals. This age-related dampening was associated with mitigated neurobehavioral consequences of sleep loss on executive functions. Furthermore, higher cortical excitability was potentially associated with better and lower executive performance, respectively, in older and younger adults. The dampening of cortical excitability dynamics found in older participants likely arises from a reduced impact of sleep homeostasis and circadian processes. It may reflect reduced brain adaptability underlying reduced cognitive flexibility in aging. Future research should confirm preliminary associations between cortical excitability and behavior and address whether maintaining cortical excitability dynamics can counteract age-related cognitive decline.

> Accéder à l’article complet : Age-related decrease in cortical excitability circadian variations during sleep loss and its links with cognition

Jacques Taillard, Patricia Sagaspe, Christian Berthomier, Marie Brandewinder, Hélène Amieva, Jean-François Dartigues, Muriel Rainfray, Sandrine Harston, Jean-Arthur Micoulaud-Franchi and Pierre Philip, Non-REM Sleep Characteristics Predict Early Cognitive Impairment in an Aging Population, Front. Neurol., Frontiers in Neurology 2019; 10, 197

Objective: Recent research suggests that sleep disorders or changes in sleep stages or EEG waveform precede over time the onset of the clinical signs of pathological cognitive impairment (e.g., Alzheimer’s disease). The aim of this study was to identify biomarkers based on EEG power values and spindle characteristics during sleep that occur in the early stages of mild cognitive impairment (MCI) in older adults.
Methods: This study was a case-control cross-sectional study with 1-year follow-up of cases. Patients with isolated subjective cognitive complaints (SCC) or MCI were recruited in the Bordeaux Memory Clinic (MEMENTO cohort). Cognitively normal controls were recruited. All participants were recorded with two successive polysomnography 1 year apart. Delta, theta, and sigma absolute spectral power and spindle characteristics (frequency, density, and amplitude) were analyzed from purified EEG during NREM and REM sleep periods during the entire second night.
Results: Twenty-nine patients (8 males, age = 71 ± 7 years) and 29 controls were recruited at T0. Logistic regression analyses demonstrated that age-related cognitive impairment were associated with a reduced delta power (odds ratio (OR) 0.072, P < 0.05), theta power (OR 0.018, P < 0.01), sigma power (OR 0.033, P < 0.05), and spindle maximal amplitude (OR 0.002, P < 0.05) during NREM sleep. Variables were adjusted on age, gender, body mass index, educational level, and medication use. Seventeen patients were evaluated at 1-year follow-up. Correlations showed that changes in self-reported sleep complaints, sleep consolidation, and spindle characteristics (spectral power, maximal amplitude, duration, and frequency) were associated with cognitive impairment (P < 0.05).
Conclusion: A reduction in slow-wave, theta and sigma activities, and a modification in spindle characteristics during NREM sleep are associated very early with a greater risk of the occurrence of cognitive impairment. Poor sleep consolidation, lower amplitude, and faster frequency of spindles may be early sleep biomarkers of worsening cognitive decline in older adults.

> Accéder à l’article complet : Non-REM Sleep Characteristics Predict Early Cognitive Impairment in an Aging Population

Maire M, Reichert CF, Gabel V, Viola AU, Phillips C, Berthomier C, Borgwardt S, Cajochen C, Schmidt C. Human brain patterns underlying vigilant attention: impact of sleep debt, circadian phase and attentional engagement. Scientific reports 2018; 8(1), 1-13.

Sleepiness and cognitive function vary over the 24-h day due to circadian and sleep-wake-dependent mechanisms. However, the underlying cerebral hallmarks associated with these variations remain to be fully established. Using functional magnetic resonance imaging (fMRI), we investigated brain responses associated with circadian and homeostatic sleep-wake-driven dynamics of subjective sleepiness throughout day and night. Healthy volunteers regularly performed a psychomotor vigilance task (PVT) in the MR-scanner during a 40-h sleep deprivation (high sleep pressure) and a 40-h multiple nap protocol (low sleep pressure). When sleep deprived, arousal-promoting thalamic activation during optimal PVT performance paralleled the time course of subjective sleepiness with peaks at night and troughs on the subsequent day. Conversely, task-related cortical activation decreased when sleepiness increased as a consequence of higher sleep debt. Under low sleep pressure, we did not observe any significant temporal association between PVT-related brain activation and subjective sleepiness. Thus, a circadian modulation in brain correlates of vigilant attention was only detectable under high sleep pressure conditions. Our data indicate that circadian and sleep homeostatic processes impact on vigilant attention via specific mechanisms; mirrored in a decline of cortical resources under high sleep pressure, opposed by a subcortical « rescuing » at adverse circadian times.

> Accéder à l’article complet : Human brain patterns underlying vigilant attention: impact of sleep debt, circadian phase and attentional engagement

Dang-Vu TT, Hatch B, Salimi A, Mograss M, Boucetta S, O’Byrne J, Brandewinder M, Berthomier C, Gouin JP., Sleep spindles may predict response to cognitive behavioral therapy for chronic insomnia, Sleep Med. 2017 Nov;39:54-61. doi: 10.1016/j.sleep.2017.08.012.

BACKGROUND: While cognitive-behavioral therapy for insomnia constitutes the first-line treatment for chronic insomnia, only few reports have investigated how sleep architecture relates to response to this treatment. In this pilot study, we aimed to determine whether pre-treatment sleep spindle density predicts treatment response to cognitive-behavioral therapy for insomnia. METHODS: Twenty-four participants with chronic primary insomnia participated in a 6-week cognitive-behavioral therapy for insomnia performed in groups of 4-6 participants. Treatment response was assessed using the Pittsburgh Sleep Quality Index and the Insomnia Severity Index measured at pre- and post-treatment, and at 3- and 12-months’ follow-up assessments. Secondary outcome measures were extracted from sleep diaries over 7 days and overnight polysomnography, obtained at pre- and post-treatment. Spindle density during stage N2-N3 sleep was extracted from polysomnography at pre-treatment. Hierarchical linear modeling analysis assessed whether sleep spindle density predicted response to cognitive-behavioral therapy. RESULTS: After adjusting for age, sex, and education level, lower spindle density at pre-treatment predicted poorer response over the 12-month follow-up, as reflected by a smaller reduction in Pittsburgh Sleep Quality Index over time. Reduced spindle density also predicted lower improvements in sleep diary sleep efficiency and wake after sleep onset immediately after treatment. There were no significant associations between spindle density and changes in the Insomnia Severity Index or polysomnography variables over time. CONCLUSION: These preliminary results suggest that inter-individual differences in sleep spindle density in insomnia may represent an endogenous biomarker predicting responsiveness to cognitive-behavioral therapy. Insomnia with altered spindle activity might constitute an insomnia subtype characterized by a neurophysiological vulnerability to sleep disruption associated with impaired responsiveness to cognitive-behavioral therapy.

> Accéder au résumé : Sleep spindles may predict response to cognitive-behavioral therapy for chronic insomnia.

Reichert CF, Maire M, Gabel V, Viola AU, Götz T, Scheffler K, Klarhöfer M, Berthomier C, Strobel W, Phillips C, Salmon E, Cajochen C, Schmidt C., Cognitive brain responses during circadian wake-promotion: evidence for sleep-pressure-dependent hypothalamic activations, Scientific reports 2017; 7(1), 1-9.

The two-process model of sleep-wake regulation posits that sleep-wake-dependent homeostatic processes interact with the circadian timing system to affect human behavior. The circadian timing system is fundamental to maintaining stable cognitive performance, as it counteracts growing homeostatic sleep pressure during daytime. Using magnetic resonance imaging, we explored brain responses underlying working memory performance during the time of maximal circadian wake-promotion under varying sleep pressure conditions. Circadian wake-promoting strength was derived from the ability to sleep during an evening nap. Hypothalamic BOLD activity was positively linked to circadian wake-promoting strength under normal, but not under disproportionally high or low sleep pressure levels. Furthermore, higher hypothalamic activity under normal sleep pressure levels predicted better performance under sleep loss. Our results reappraise the two-process model by revealing a homeostatic-dose-dependent association between circadian wake-promotion and cognition-related hypothalamic activity.

> Accéder à l’article complet : Cognitive brain responses during circadian wake-promotion: evidence for sleep-pressure-dependent hypothalamic activations

Vallat R, Lajnef T, Eichenlaub JB, Berthomier C, Jerbi K, Morlet D, Ruby PM., Increased Evoked Potentials to Arousing Auditory Stimuli during Sleep: Implication for the Understanding of Dream Recall. Front Hum Neurosci. 2017 Mar 21;11:132. doi: 10.3389/fnhum.2017.00132. eCollection 2017.

High dream recallers (HR) show a larger brain reactivity to auditory stimuli during wakefulness and sleep as compared to low dream recallers (LR) and also more intra-sleep wakefulness (ISW), but no other modification of the sleep macrostructure. To further understand the possible causal link between brain responses, ISW and dream recall, we investigated the sleep microstructure of HR and LR, and tested whether the amplitude of auditory evoked potentials (AEPs) was predictive of arousing reactions during sleep. Participants (18 HR, 18 LR) were presented with sounds during a whole night of sleep in the lab and polysomnographic data were recorded. Sleep microstructure (arousals, rapid eye movements (REMs), muscle twitches (MTs), spindles, KCs) was assessed using visual, semi-automatic and automatic validated methods. AEPs to arousing (awakenings or arousals) and non-arousing stimuli were subsequently computed. No between-group difference in the microstructure of sleep was found. In N2 sleep, auditory arousing stimuli elicited a larger parieto-occipital positivity and an increased late frontal negativity as compared to non-arousing stimuli. As compared to LR, HR showed more arousing stimuli and more long awakenings, regardless of the sleep stage but did not show more numerous or longer arousals. These results suggest that the amplitude of the brain response to stimuli during sleep determine subsequent awakening and that awakening duration (and not arousal) is the critical parameter for dream recall. Notably, our results led us to propose that the minimum necessary duration of an awakening during sleep for a successful encoding of dreams into long-term memory is approximately 2 min.

> Accéder à l’article complet : Increased Evoked Potentials to Arousing Auditory Stimuli during Sleep: Implication for the Understanding of Dream

Eichenlaub JB, Bertrand O, Morlet D, Ruby P. Brain Reactivity Differentiates Subjects with High and Low Dream Recall Frequencies during Both Sleep and Wakefulness. Cereb. Cortex 24 (5): 1206-1215. 2014

The neurophysiological correlates of dreaming remain unclear. According to the « arousal-retrieval » model, dream encoding depends on intrasleep wakefulness. Consistent with this model, subjects with high and low dream recall frequency (DRF) report differences in intrasleep awakenings. This suggests a possible neurophysiological trait difference between the 2 groups. To test this hypothesis, we compared the brain reactivity (evoked potentials) of subjects with high (HR, N = 18) and low (LR, N = 18) DRF during wakefulness and sleep. During data acquisition, the subjects were presented with sounds to be ignored (first names randomly presented among pure tones) while they were watching a silent movie or sleeping. Brain responses to first names dramatically differed between the 2 groups during both sleep and wakefulness. During wakefulness, the attention-orienting brain response (P3a) and a late parietal response were larger in HR than in LR. During sleep, we also observed between-group differences at the latency of the P3a during N2 and at later latencies during all sleep stages. Our results demonstrate differences in the brain reactivity of HR and LR during both sleep and wakefulness. These results suggest that the ability to recall dreaming is associated with a particular cerebral functional organization, regardless of the state of vigilance.

> Accéder à l’article complet : Brain Reactivity Differentiates Subjects with High and Low Dream Recall Frequencies during Both Sleep and Wakefulness

Ruby P, Blochet C, Eichenlaub J-B, Bertrand O, Morlet D, Bidet-Caulet A. Alpha Reactivity to Complex Sounds Differs during REM Sleep and Wakefulness. PLoS ONE 8(11): e79989, 2013.

We aimed at better understanding the brain mechanisms involved in the processing of alerting meaningful sounds during sleep, investigating alpha activity. During EEG acquisition, subjects were presented with a passive auditory oddball paradigm including rare complex sounds called Novels (the own first name – OWN, and an unfamiliar first name – OTHER) while they were watching a silent movie in the evening or sleeping at night. During the experimental night, the subjects’ quality of sleep was generally preserved. During wakefulness, the decrease in alpha power (8–12 Hz) induced by Novels was significantly larger for OWN than for OTHER at parietal electrodes, between 600 and 900 ms after stimulus onset. Conversely, during REM sleep, Novels induced an increase in alpha power (from 0 to 1200 ms at all electrodes), significantly larger for OWN than for OTHER at several parietal electrodes between 700 and 1200 ms after stimulus onset. These results show that complex sounds have a different effect on the alpha power during wakefulness (decrease) and during REM sleep (increase) and that OWN induce a specific effect in these two states. The increased alpha power induced by Novels during REM sleep may 1) correspond to a short and transient increase in arousal; in this case, our study provides an objective measure of the greater arousing power of OWN over OTHER, 2) indicate a cortical inhibition associated with sleep protection. These results suggest that alpha modulation could participate in the selection of stimuli to be further processed during sleep.

> Accéder à l’article complet : Alpha Reactivity to Complex Sounds Differs during REM Sleep and Wakefulness

Ruby P, Blochet C, Eichenlaub JB, Bertrand O, Morlet D, Bidet-Caulet A. Alpha reactivity to first names differs in subjects with high and low dream recall frequency. Front Psychol.;4:419, 2013.

Studies in cognitive psychology showed that personality (openness to experience, thin boundaries, absorption), creativity, nocturnal awakenings, and attitude toward dreams are significantly related to dream recall frequency (DRF). These results suggest the possibility of neurophysiological trait differences between subjects with high and low DRF. To test this hypothesis we compared sleep characteristics and alpha reactivity to sounds in subjects with high and low DRF using polysomnographic recordings and electroencephalography (EEG). We acquired EEG from 21 channels in 36 healthy subjects while they were presented with a passive auditory oddball paradigm (frequent standard tones, rare deviant tones and very rare first names) during wakefulness and sleep (intensity, 50 dB above the subject’s hearing level). Subjects were selected as High-recallers (HR, DRF = 4.42 ± 0.25 SEM, dream recalls per week) and Low-recallers (LR, DRF = 0.25 ± 0.02) using a questionnaire and an interview on sleep and dream habits. Despite the disturbing setup, the subjects’ quality of sleep was generally preserved. First names induced a more sustained decrease in alpha activity in HR than in LR at Pz (1000–1200 ms) during wakefulness, but no group difference was found in REM sleep. The current dominant hypothesis proposes that alpha rhythms would be involved in the active inhibition of the brain regions not involved in the ongoing brain operation. According to this hypothesis, a more sustained alpha decrease in HR would reflect a longer release of inhibition, suggesting a deeper processing of complex sounds than in LR during wakefulness. A possibility to explain the absence of group difference during sleep is that increase in alpha power in HR may have resulted in awakenings. Our results support this hypothesis since HR experienced more intra sleep wakefulness than LR (30 ± 4 vs. 14 ± 4 min). As a whole our results support the hypothesis of neurophysiological trait differences in high and low-recallers.

> Accéder à l’article complet : Alpha reactivity to first names differs in subjects with high and low dream recall frequency  

Schmidt C, Peigneux P, Leclercq Y, Sterpenich V, Vandewalle G, Philips C, Berthomier P, Berthomier C, Tinguely G, Gais S, Schabus M, Desseilles M, Dang-Vu T, Salmon E, Degueldre C, Balteau E, Luxen A, Cajochen C, Maquet P, Collette F. Circadian preference modulates the neural substrate of conflict processing across the day. PLoS One. 2012;7(1):e29658. 2012 Jan 4. PLoS One. 2012;7(1):e29658. 2012 Jan 4.

Human morning and evening chronotypes differ in their preferred timing for sleep and wakefulness, as well as in optimal daytime periods to cope with cognitive challenges. Recent evidence suggests that these preferences are not a simple by-product of socio-professional timing constraints, but can be driven by inter-individual differences in the expression of circadian and homeostatic sleep-wake promoting signals. Chronotypes thus constitute a unique tool to access the interplay between those processes under normally entrained day-night conditions, and to investigate how they impinge onto higher cognitive control processes. Using functional magnetic resonance imaging (fMRI), we assessed the influence of chronotype and time-of-day on conflict processing-related cerebral activity throughout a normal waking day. Sixteen morning and 15 evening types were recorded at two individually adapted time points (1.5 versus 10.5 hours spent awake) while performing the Stroop paradigm. Results show that interference-related hemodynamic responses are maintained or even increased in evening types from the subjective morning to the subjective evening in a set of brain areas playing a pivotal role in successful inhibitory functioning, whereas they decreased in morning types under the same conditions. Furthermore, during the evening hours, activity in a posterior hypothalamic region putatively involved in sleep-wake regulation correlated in a chronotype-specific manner with slow wave activity at the beginning of the night, an index of accumulated homeostatic sleep pressure. These results shed light into the cerebral mechanisms underlying inter-individual differences of higher-order cognitive state maintenance under normally entrained day-night conditions.

> Accéder à l’article complet : Circadian preference modulates the neural substrate of conflict processing across the day

Tankéré P, Taillard J, Armeni MA, Petitjean T, Berthomier C, Strauss M, Peter-Derex L. Revisiting the maintenance of wakefulness test: from intra-/inter-scorer agreement to normative values in patients treated for obstructive sleep apnea. J Sleep Res. 2024 May;33(3):e13961. doi: 10.1111/jsr.13961. Epub 2023 Jun 7. PMID: 37287324.

Variability of sleep stage scoring in late midlife and early old age, Chylinski D., Berthomier C., Lambot E., Frenette S., Brandewinder M., Carrier J., Vandewalle G. & Muto V.  J Sleep Res. 2021 Jun 24:e13424. doi: 10.1111/jsr.13424. Epub ahead of print. PMID: 34169604.

Study objectives: To assess the performance of the single-channel automatic sleep staging (AS) software ASEEGA in adult patients diagnosed with various sleep disorders.

Methods: Sleep recordings were included of 95 patients (38 women, 40.5 ± 13.7 years) diagnosed with insomnia (n = 23), idiopathic hypersomnia (n = 24), narcolepsy (n = 24), and obstructive sleep apnea (n = 24). Visual staging (VS) was performed by two experts (VS1 and VS2) according to the American Academy of Sleep Medicine rules. AS was based on the analysis of a single electroencephalogram channel (Cz-Pz), without any information from electro-oculography nor electromyography. The epoch-by-epoch agreement (concordance and Conger’s coefficient [κ]) was compared pairwise (VS1-VS2, AS-VS1, AS-VS2) and between AS and consensual VS. Sleep parameters were also compared.

Results: The pairwise agreements were: between AS and VS1, 78.6% (κ = 0.70); AS and VS2, 75.0% (0.65); and VS1 and VS2, 79.5% (0.72). Agreement between AS and consensual VS was 85.6% (0.80), with the following distribution: insomnia 85.5% (0.80), narcolepsy 83.8% (0.78), idiopathic hypersomnia 86.1% (0.68), and obstructive sleep disorder 87.2% (0.82). A significant low-amplitude scorer effect was observed for most sleep parameters, not always driven by the same scorer. Hypnograms obtained with AS and VS exhibited very close sleep organization, except for 80% of rapid eye movement sleep onset in the group diagnosed with narcolepsy missed by AS.

Conclusions: Agreement between AS and VS in sleep disorders is comparable to that reported in healthy individuals and to interexpert agreement in patients. ASEEGA could therefore be considered as a complementary sleep stage scoring tool in clinical practice, after improvement of rapid eye movement sleep onset detection.

> Access Variability of sleep stage scoring in late midlife and early old age

Exploring scoring methods for research studies: Accuracy and variability of visual and automated sleep scoring. Berthomier C, Muto V, Schmidt C, Vandewalle G, Jaspar M, Devillers J, Gaggioni G, Chellappa SL, Meyer C, Phillips C, Salmon E, Berthomier P, Prado J, Benoit O, Bouet R, Brandewinder M, Mattout J, Maquet P. Journal of sleep research 2020; 29(5):e12994.

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 algorithm was used to characterize inter-scoring variability. A second dataset (DS2, 88 recordings) scored a few weeks later was used to explore intra-expert variability. 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 autoscoring 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 variability, making them a sensible option to reduce exogenous variability and give access to the endogenous variability in the data.

> Accéder à l’article Exploring scoring methods for research studies: Accuracy and variability of visual and automated sleep scoring

Berthomier C; Drouot X; Herman-Stoïca M; Berthomier P; Prado J; Bokar-Thire D; Benoit O; Mattout J; d’Ortho MP., Automatic Analysis of Single-Channel Sleep EEG: Validation in Healthy Individuals, Sleep 2007;30(11):1587-1595.

STUDY OBJECTIVE: To assess the performance of automatic sleep scoring software (ASEEGA) based on a single EEG channel comparatively with manual scoring (2 experts) of conventional full polysomnograms. DESIGN: Polysomnograms from 15 healthy individuals were scored by 2 independent experts using conventional R&K rules. The results were compared to those of ASEEGA scoring on an epoch-by-epoch basis. SETTING: Sleep laboratory in the physiology department of a teaching hospital. PARTICIPANTS: Fifteen healthy volunteers. MEASUREMENTS AND RESULTS: The epoch-by-epoch comparison was based on classifying into 2 states (wake/sleep), 3 states (wake/REM/ NREM), 4 states (wake/REM/stages 1-2/SWS), or 5 states (wake/REM/ stage 1/stage 2/SWS). The obtained overall agreements, as quantified by the kappa coefficient, were 0.82, 0.81, 0.75, and 0.72, respectively. Furthermore, obtained agreements between ASEEGA and the expert consensual scoring were 96.0%, 92.1%, 84.9%, and 82.9%, respectively. Finally, when classifying into 5 states, the sensitivity and positive predictive value of ASEEGA regarding wakefulness were 82.5% and 89.7%, respectively. Similarly, sensitivity and positive predictive value regarding REM state were 83.0% and 89.1%. CONCLUSIONS: Our results establish the face validity and convergent validity of ASEEGA for single-channel sleep analysis in healthy individuals. ASEEGA appears as a good candidate for diagnostic aid and automatic ambulant scoring.

> Accéder à l’article complet : Automatic Analysis of Single-Channel Sleep EEG: Validation in Healthy Individuals

Association of Alzheimer’s disease genetic risk and EEG features of the awake brain in healthy young men, N Mortazavi, E Koshmanova, V Muto, D Chylinski, M Jaspar, C Meyer, R Sharifpour, A Berger, I Paparella, I Campbell, E Beckers, C Degueldre, C Berthomier, C Schmidt, F Collette, D Dijk, C Phillips, P Maquet, P Talwar, G Vandewalle

26th Conference of the European Sleep Research Society (ESRS 2022)

Locus coeruleus reactivity during wakefulness is associated with REM sleep intensity, E Koshmanova, A Berger, N Mortazavi, E Beckers, J Ji, I Campbell, R Sharifpour, I Paparella, D Chylinski, V Muto,

26th Conference of the European Sleep Research Society (ESRS 2022)

Alzheimer’s disease genetic risk and electroencephalography signals during wakefulness: Insights into the possible disease correlation, N Mortazavi, E Koshmanova, V Muto, D Chylinski, M Jaspar, C Meyer, R Sharifpour, A Berger, I Paparella, I Campbell, E Beckers, C Degueldre, C Berthomier, C Schmidt, F Collette, DJ Dijk, C Phillips, P Maquet, P Talwar, G Vandewalle

The 26th Conference of the European Sleep Research Society (ESRS 2022)

Modelling age-related changes in human sleep across the 24h-cycle: impact of circadian amplitude and wake-promoting inputs to the monoaminergic system, S de Haan, M Baillet, M Deantoni, M Reyt, M Dourte, V Muto, C Phillips, C Phillips, P Maquet, C Berthomier, S Postnova, C Schmidt, G Hammad

Sleep Europe 2022

Spindle-slow wave coupling is linked to early amyloid-β burden and predicts memory decline, D Chylinski, M Van Egroo, J Narbutas, V Muto, MA Bahri, C Berthomier, M Brandewinder,, E Salmon, C Bastin, C Phillips

Gordon conference on Sleep Function, 2022

Timely sleep coupling: phase locked slow wave-spindle pairing is linked to AD neuropathology and forecasts cognitive decline, D Chylinski, M Van Egroo, J Narbutas, C Berthomier, M Brandewinder, E Salmon, MA Bahri, V Muto, C Bastin, F Collette

Belgian Association for Sleep research and Sleep medicine, 2021

Ghaemmaghami P, Muto V, Jaspar M, Meyer C, Elansary M, VanEgroo M, Berthomier C, Lambot E, Brandewinder M, Luxen A, Degueldre C, Salmon E, Archer SN, Phillips C, Dijk D, Posthuma D, Van Someren E, Collette F, Georges M, Maquet P and Vandewalle G (2018). The genetic liability for insomnia is associated with lower amount of slow wave sleep in young and healthy individuals. Front. Neurosci. Conference Abstract: Belgian Brain Congress 2018 — Belgian Brain Council. doi: 10.3389/conf.fnins.2018.95.00069

> Accéder à l’article : The genetic liability for insomnia is associated with lower amount of slow wave sleep in young and healthy individuals.

Sagaspe P, Taillard J, Chaufton C, Berthomier C, Brandewinder M, Amiéva H, Dartigues J-F, Philip P. Polysomnographic data in patients with isolated memory complaints or mild cognitive impairment. J. Sleep Res., 23 Suppl. 1:240, 2014 22nd ESRS Congress, Tallinn, Estonia 16 – 20 September 2014

P. J. Escourrou, M. Brandewinder, C. Berthomier, P. Berthomier, G. Baffet, Z. Balekji, N. Puisais, G. Roisman, Respiratory events during stable wake in sleep apnea patients: occurrence and mechanism., European Respiratory Journal 2018 52: PA2509; DOI: 10.1183/13993003.congress-2018.PA2509

Escourrou P., Berthomier C., Belkji Z., Brandewinder M., Berthomier P., Piedvache C., Agostini H., Puisais N., Roisman G., Polygraphy + with one EEG Channel Improves OSAS Severity Classification, Sleep, Volume 41, Issue suppl_1, April 2018, Page A185, https://doi.org/10.1093/sleep/zsy061.491

APSS Baltimore
June 2018

O’Byrne J, Boucetta S, Reed L,Malhi O, Zhang V, Arcelin A, Wenzel K, Brandewinder M, Berthomier C, Gouin J-P, Dang-Vu TT. Spindles and slow waves predict treatment responses to cognitive-behavioural therapy for chronic primary insomnia. J. Sleep Res., 23 Suppl. 1:209, 2014 22nd ESRS Congress, Tallinn, Estonia 16 – 20 September 2014