IMT Institutional Repository: No conditions. Results ordered -Date Deposited. 2024-03-29T02:02:13ZEPrintshttp://eprints.imtlucca.it/images/logowhite.pnghttp://eprints.imtlucca.it/2017-09-05T06:41:38Z2017-09-05T06:41:38Zhttp://eprints.imtlucca.it/id/eprint/3781This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37812017-09-05T06:41:38ZThe effects of acute, short-term visual deprivation
on low-frequency EEG activity during wakefulness and sleepIntroduction: experimental evidence indicates that regional changes in slow-wave activity (SWA, 0.5-4.5 Hz) during NREM-sleep, and in theta activity (5-9 Hz) during wakefulness may reflect local variations in sleep need induced by recent experience-dependent brain plasticity1. However, such evidence is mainly based on studies involving the sensorimotor domain. Previous attempts to extend these findings to a purely sensory system –such as the visual system– provided contradictory results. To clarify this issue, here we evaluated the effects of short-term visual deprivation on low-frequency EEG activity during wakefulness and sleep.
Materials and Methods: twelve healthy volunteers (25.5±3.7 yrs, 6 M) participated to two experimental sessions (order counterbalanced across participants), each lasting from ~2.30 pm to ~8.30 am of the following day: a visual deprivation (VD) condition, during which subjects were blindfolded, and a visual stimulation (VS) condition. All activities were rigorously regulated: in VD, subjects had to listen to audiobooks for ~6 h, while in VS they watched movies for a similar amount of time. All participants slept for ~7.5 h (11.30 pm – 7.00 am), while their brain activity was recorded using high-density (hd-)EEG (256 electrodes). Brief test sessions including an auditory psychomotor vigilance test (aPVT) and Likert-scales for sleepiness, alertness and mood were completed every 2 h and ~40 min after awakening. Three 2 min eyes closed hd-EEG recordings were obtained before and after sleep to investigate potential variations in local theta power. Mean SWA, slow wave density and amplitude6 were calculated for the first 20 min of NREM-sleep. Statistical analyses (paired t-tests) were restricted to an occipital and a centro-frontal region of interest (ROI).
Results: relative to VS, VD was associated with reduced N1 and REM latency and with increased REM duration and proportion (p < 0.05). No differences were observed in other sleep parameters. No significant differences between VS and VD were observed in aPVT reaction time, subjective sleepiness, alertness and mood either before or after sleep. In eyes-closed wake recordings before sleep, occipital (but not frontal) theta power was higher after VS than after VD (p < 0.03; ~11.00 pm) and this difference disappeared after a night of sleep (p > 0.23; ~8.00 am). During the first 20 min of NREM-sleep, SWA and slow wave amplitude showed no significant differences across experimental condition. However, the density of occipital (but not frontal) slow waves tended to be higher in VS (p = 0.09). Additional analyses showed that small (amplitude < 30 µV), occipital (but not large and/or frontal) slow waves were significantly more numerous after VS than after VD (p < 0.02).
Discussion: short-term visual deprivation is associated with an occipital decrease in theta activity during wakefulness, and in the density of small, local slow waves during NREM-sleep, likely reflecting local, experience-related changes in cortical plasticity. However, in contrast to previous observations involving the sensorimotor domain, sleep SWA and slow wave amplitude showed no clear changes, suggesting that important regional differences may exist with respect to the morphology of slow waves and their relation to experience-dependent modifications.Giulio BernardiMonica Bettamonica.betta@imtlucca.itJacinthe CataldiAndrea LeoEmiliano Ricciardiemiliano.ricciardi@imtlucca.itJ. Haba-RubioPietro Pietrinipietro.pietrini@imtlucca.itR. HeinzerFrancesca Siclari2017-09-04T15:21:57Z2017-09-04T15:21:57Zhttp://eprints.imtlucca.it/id/eprint/3780This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37802017-09-04T15:21:57ZQuantifying peripheral sympathetic activation during sleep by means of an automatic method for pulse wave amplitude drop detectionIntroduction: drops in pulse wave amplitude (PWA) measured by finger photoplethysmography (PPG) are known to reflect peripheral vasoconstriction resulting from sympathetic activation. Quantifying the amount of sympathetic activation during sleep would be useful to investigate the link between sleep disorders, like sleep apnea, and cardio-vascular morbidity-mortality. However, automatic algorithms allowing for a simple and rapid extraction and characterization of PWA parameters are not readily available. Therefore, in the present study we developed and validated a novel automatic approach to detect and characterize PWA-drops in whole-night polysomnographic (PSG) data.
Materials and Methods: PSG recordings of 9 patients (52±5yrs, 7F) from the HypnoLaus Sleep Cohort were analyzed. The PPG signal was smoothed and detrended before extraction of the PWA signal, defined at each cardiac cycle as the difference between the peak and nadir values of the corresponding PPG-waveform. The time-courses of PWA variance and first-derivative were then evaluated using a moving-window over 5 heartbeats. Candidate time-points for potential PWA-drops were defined as local peaks in the PWA-variance showing correspondent first-derivative negative values. For each PWA-drop candidate, an observation interval was delimited between the closest previous and subsequent PWA maxima, and the maximum percent decrease (amplitude) was computed with respect to the mean of the previous 5 PWA values extracted from stable signal tracts (low local variance and duration >2sec). Then, PWA-drops with amplitude >30% and duration >4 heartbeats were identified, and their amplitude (%), descending slope (%/s) and total duration (s) were estimated. The PWA-drop index was calculated as the number of drops per hour. The algorithm detections were compared with those of an expert scorer who marked PWA-drops with amplitudes >30% (3min scoring window).
Results: with respect to the human scorer, the algorithm achieved a sensitivity of 97.4%, a specificity of 89.5%, and a precision of 49.6%. In spite of the apparently low precision, both visual inspection and a direct comparison between false positive (FP) and true positive (TP) detections showed that the algorithm correctly identified above-threshold drops that were missed by the human scorer (minimum amplitude was 32.1±1.5% for FP, and 37.6±3.7% for TP). Only ~31% of all detected PWA-drops were associated with a (visually scored) EEG-arousal, whereas most EEG-arousals (~72%) showed an association with a PWA-drop. Interestingly, among PWA-drops that were not associated with a scored EEG-arousal, 19-55% (depending on sleep stage) were nevertheless accompanied by a strong increase in high-frequency EEG-power, potentially reflecting a cortical activation not visible to the human eye. Finally, the index, amplitude and duration tended to decrease from light (N1) to deep (N3) NREM sleep (p<0.05, rmANOVA), while REM sleep showed a significantly higher PWA-drop index compared to NREM stages (53.5±19.3d/h vs. 42.1±18.7d/h in N1).
Discussion: the automatic algorithm allowed to reliably detect PWA-drops occurring in all sleep stages, including events not recognized upon standard visual inspection. This automatic algorithm may represent a simple and useful tool to quantify the degree of peripheral sympathetic activation during sleep and may provide relevant information about associated ‘cortical activations’ during sleep.Monica Bettamonica.betta@imtlucca.itGiulio BernardiEmiliano Ricciardiemiliano.ricciardi@imtlucca.itPietro Pietrinipietro.pietrini@imtlucca.itJ. Haba-RubioFrancesca SiclariR. Heinzer2017-09-04T14:50:49Z2017-09-04T14:50:49Zhttp://eprints.imtlucca.it/id/eprint/3779This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37792017-09-04T14:50:49ZRegionally specific features of low-frequency EEG oscillations during REM-sleepGiulio BernardiMonica Bettamonica.betta@imtlucca.itYu XiaoqianEmiliano Ricciardiemiliano.ricciardi@imtlucca.itJ. Haba-RubioR. HeinzerPietro Pietrinipietro.pietrini@imtlucca.itGiulio TononiFrancesca Siclari2017-09-04T14:47:55Z2017-09-04T14:47:55Zhttp://eprints.imtlucca.it/id/eprint/3778This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37782017-09-04T14:47:55ZSpontaneous, localized EEG activations in REM sleep: an high-density EEG investigationMonica Bettamonica.betta@imtlucca.itGiulio BernardiDanilo MenicucciJ. Haba-RubioR. HeinzerAngelo GemignaniAlberto LandiGiulio TononiFrancesca Siclari2017-09-04T14:28:17Z2017-09-04T14:28:17Zhttp://eprints.imtlucca.it/id/eprint/3777This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37772017-09-04T14:28:17ZOptimal Varicella immunization programs for both Varicella and Herpes Zoster ControlA main obstacle to the widespread adoption of varicella immunization in Europe has been the fear of a subsequent boom in natural herpes zoster caused by the decline in the protective effect of natural immunity boosting due to reduced virus circulation. We apply optimal control to simple models for VZV transmission and reactivation to investigate existence and feasibility of temporal paths of varicella childhood immunization that are optimal in controlling both varicella and zoster. We analyze the optimality system numerically focusing on the role played by the structure of the cost functional, the relative cost zoster-varicella, and the length of the planning horizon. We show that optimal programs exist but will mostly be unfeasible in real public health contexts due to their complex temporal profiles. This complexity is the consequence of the intrinsically antagonistic nature of varicella immunization programs when aimed to control both varicella and herpes zoster. However we could show that gradually increasing, smooth – thereby feasible - vaccination schedules, can perform largely better than routine programs with constant vaccine uptake. Moreover we show the optimal temporal profiles of feasible immunization
programs targeting with priority the mitigation of the post-immunization natural zoster boom.Monica Bettamonica.betta@imtlucca.itMarco LaurinoAndrea PuglieseGiorgio GuzzettaAlberto LandiPiero Manfredi2017-09-04T14:16:28Z2017-09-04T14:17:39Zhttp://eprints.imtlucca.it/id/eprint/3776This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37762017-09-04T14:16:28ZPerspectives on optimal control of Varicella and Herpes Zoster by mass routine varicella vaccination: the effects of Immunity BoostingMonica Bettamonica.betta@imtlucca.itMarco LaurinoA. PuglieseGiorgio GuzzettaAlberto LandiPiero Manfredi2017-09-04T14:07:48Z2017-09-04T14:07:48Zhttp://eprints.imtlucca.it/id/eprint/3775This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37752017-09-04T14:07:48ZAlgoritmo per il riconoscimento, classificazione e rimozione degli artefatti da movimenti oculari dal segnale EEG durante il sonno REMMonica Bettamonica.betta@imtlucca.itDanilo MenicucciMarco LaurinoA. PiarulliAlberto LandiAngelo Gemignani2017-09-04T13:57:00Z2017-09-04T13:57:00Zhttp://eprints.imtlucca.it/id/eprint/3774This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37742017-09-04T13:57:00ZDetection and removal of ocular artifacts from EEG signals for an automated REM sleep analysisRapid eye movements (REMs) are a prominent feature of REM sleep, and their distribution and time density over the night represent important physiological and clinical parameters. At the same time, REMs produce substantial distortions on the electroencephalographic (EEG) signals, which strongly affect the significance of normal REM sleep quantitative study. In this work a new procedure for a complete and automated analysis of REM sleep is proposed, which includes both a REMs detection algorithm and an ocular artifact removal system. The two steps, based respectively on Wavelet Transform and adaptive filtering, are fully integrated and their performance is evaluated using REM simulated signals. Thanks to the integration with the detection algorithm, the proposed artifact removal system shows an enhanced accuracy in the recovering of the true EEG signal, compared to a system based on the adaptive filtering only. Finally the artifact removal system is applied to physiological data and an estimation of the actual distortion induced by REMs on EEG signals is supplied.Monica Bettamonica.betta@imtlucca.itAngelo GemignaniAlberto LandiMarco LaurinoPaolo PiaggiDanilo Menicucci2017-09-04T13:51:16Z2017-09-04T13:51:16Zhttp://eprints.imtlucca.it/id/eprint/3773This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37732017-09-04T13:51:16ZCombining pharmacological therapy and vaccination in Chronic Myeloid Leukemia via model predictive controlThis paper describes a simulation study which aims at optimizing the therapy for the control of Chronic Myeloid Leukemia according to the following objectives: the reduction of the administered drug and vaccine amounts, the establishment of a auto-immune response and the long-term control of disease without reducing the effective of therapy with respect to the full treatment. A therapy optimization method is developed defining and solving a Model Predictive Control algorithm, preceded by an accurate Initial Guess search based on Monte-Carlo like approach. Simulation results show that the suggested procedure achieves the proposed goals.Marco LaurinoMaurizio StanoMonica Bettamonica.betta@imtlucca.itGabriele PannocchiaAlberto Landi2017-09-04T13:48:18Z2017-09-04T13:48:18Zhttp://eprints.imtlucca.it/id/eprint/3772This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37722017-09-04T13:48:18ZA Classification method for eye movements direction during REM sleep trained on wake electro-oculographic recordingsRapid eye movements (REMs) are a peculiar and intriguing aspect of REM sleep, even if their physiological function still remains unclear. During this work, a new automatic tool was developed, aimed at a complete description of REMs activity during the night, both in terms of their timing of occurrence that in term of their directional properties. A classification stage of each singular movement detected during the night according to its main direction, was in fact added to our procedure of REMs detection and ocular artifact removal. A supervised classifier was constructed, using as training and validation set EOG data recorded during voluntary saccades of five healthy volunteers. Different classification methods were tested and compared. The further information about REMs directional characteristic provided by the procedure would represent a valuable tool for a deeper investigation into REMs physiological origin and functional meaning.Monica Bettamonica.betta@imtlucca.itMarco LaurinoAngelo GemignaniAlberto LandiD. Menicucci2017-09-04T13:44:51Z2017-09-04T13:44:51Zhttp://eprints.imtlucca.it/id/eprint/3771This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37712017-09-04T13:44:51ZProcoagulant control strategies for the human blood clotting processThis paper describes the comparison between two drug control strategies to hemophilia A. To emulate blood clotting and the pathological condition of hemophilia, a mathematical model composed by 14 ordinary differential equations is considered. We adopt a variable structure non-linear PID approach and a Model Predictive Control in order to control the dosage of procoagulant factor used in the treatment of hemophiliac patient. The two control actions are sampled for a practical application. Finally, we discuss and compare the results of the two control approaches, introducing a suited control index (eINR).Marco LaurinoTommaso MenaraAlessandro StellaMonica Bettamonica.betta@imtlucca.itAlberto Landi2017-09-04T13:40:21Z2017-09-04T13:40:21Zhttp://eprints.imtlucca.it/id/eprint/3770This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/37702017-09-04T13:40:21ZPerspectives on optimal control of varicella and herpes zoster by mass routine varicella vaccinationHerpes zoster arises from reactivation of the varicella–zoster virus (VZV), causing varicella in children. As reactivation occurs when cell-mediated immunity (CMI) declines, and there is evidence that re-exposure to VZV boosts CMI, mass varicella immunization might increase the zoster burden, at least for some decades. Fear of this natural zoster boom is the main reason for the paralysis of varicella immunization in Europe. We apply optimal control to a realistically parametrized age-structured model for VZV transmission and reactivation to investigate whether feasible varicella immunization paths that are optimal in controlling both varicella and zoster exist. We analyse the optimality system numerically focusing on the role of the cost functional, of the relative zoster–varicella cost and of the planning horizon length. We show that optimal programmes will mostly be unfeasible for public health owing to their complex temporal profiles. This complexity is the consequence of the intrinsically antagonistic nature of varicella immunization programmes when aiming to control both varicella and zoster. However, we show that gradually increasing—hence feasible—vaccination schedules can perform better than routine programmes with constant vaccine uptake. Finally, we show the optimal profiles of feasible programmes targeting mitigation of the post-immunization natural zoster boom with priority.Monica Bettamonica.betta@imtlucca.itMarco LaurinoAndrea PuglieseGiorgio GuzzettaAlberto LandiPiero Manfredi2017-03-21T13:49:11Z2017-09-04T13:34:32Zhttp://eprints.imtlucca.it/id/eprint/3678This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/36782017-03-21T13:49:11ZLow-frequency oscillations in REM-sleep: a high density
EEG studyObjectives: Slow waves (0.5–4 Hz) of non-rapid eye movement
(NREM) sleep occur and are regulated locally, in an experiencedependent
manner. However, recent work in mice showed that
region-specific slow waves may also occur in REM sleep. Here we
investigated the presence and cortical distribution of low-frequency
oscillations in human REM sleep using high-density EEG.Giulio BernardiMonica Bettamonica.betta@imtlucca.itX. YuEmiliano Ricciardiemiliano.ricciardi@imtlucca.itJ. Haba-RubioR. HeinzerPietro Pietrinipietro.pietrini@imtlucca.itGiulio TononiFrancesca Siclari