Combining Cardiac Monitoring with Actigraphy Aids Nocturnal Arousal Detection during Ambulatory Sleep Assessment in Insomnia

Study Objectives: The objective assessment of insomnia has remained difficult. Multisensory devices collecting heart rate (HR) and motion are regarded as the future of ambulatory sleep monitoring. Unfortunately, reports on altered average HR or heart rate variability (HRV) during sleep in insomnia are equivocal. Here, we evaluated whether the objective quantification of insomnia improves by assessing state-related changes in cardiac measures. Methods: We recorded electrocardiography, posture, and actigraphy in 33 people without sleep complaints and 158 patients with mild to severe insomnia over 4 d in their home environment. At the microscale, we investigated whether HR changed with proximity to gross (body) and small (wrist) movements at nighttime. At the macroscale, we calculated day-night differences in HR and HRV measures. For both timescales, we tested whether outcome measures were related to insomnia diagnosis and severity. Results: At the microscale, an increase in HR was often detectable already 60 s prior to as well as following a nocturnal chest, but not wrist, movement. This increase was slightly steeper in insomnia and was associated with insomnia severity, but future EEG recordings are necessary to elucidate whether these changes occur prior to or simultaneously with PSG-indicators of wakefulness. At the macroscale, we found an attenuated cardiac response to sleep in insomnia: patients consistently showed smaller day-night differences in HR and HRV. Conclusions: Incorporating state-related changes in cardiac features in the ambulatory monitoring of sleep might provide a more sensitive biomarker of insomnia than the use of cardiac activity averages or actigraphy alone

Sleep and circadian rhythms in the acute phase of moderate to severe traumatic brain injury

Les traumatismes craniocérébraux (TCC) sont la principale cause d’invalidité chez les jeunes adultes, engendrant d’importantes séquelles cognitives, physiologiques et comportementales. Les perturbations du cycle veille-sommeil sont parmi les symptômes les plus persistants à la suite d’un TCC et pourraient nuire à la récupération. En effet, le sommeil est nécessaire à l’apprentissage, la plasticité cérébrale et la génération de nouveaux neurones dans le cerveau adulte. Les observations cliniques suggèrent que ces perturbations apparaissent dès les premières semaines suivant le TCC et pourraient suggérer une altération de l’horloge circadienne. Cependant, aucune étude n’a encore documenté comment les perturbations du cycle veille-sommeil émergent et évoluent dans la phase aiguë du TCC, ni leur association à la récupération fonctionnelle et cognitive à court-terme. Conséquemment, cette thèse vise à caractériser le sommeil et les rythmes circadiens des patients hospitalisés avec un TCC modéré ou sévère et déterminer si les perturbations du cycle veille-sommeil sont causées par un dérèglement de l’horloge circadienne. Pour ce faire, nous avons utilisé des mesures objectives et quantitatives de sommeil et des rythmes circadiens, incluant l’actigraphie, la polysomnographie (PSG) et la mélatonine, dès la phase d’éveil aux soins intensif. Afin de comprendre le rôle du TCC dans ces perturbations, nous avons comparé les patients TCC à des patients hospitalisés avec blessures orthopédiques graves, sans TCC. Ce protocole a mené à cinq articles de recherche. En premier lieu, nous démontrons que le cycle veille-sommeil des patients TCC est sévèrement perturbé, mais s’améliore chez 50% d’entre eux au cours de leur séjour hospitalier. Les patients avec une amélioration de la consolidation du cycle veille-sommeil ont un meilleur fonctionnement cognitif et fonctionnel au congé de l’hôpital. Ensuite, dans une étude de cas, nous démontrons qu’un patient TCC peut avoir un cycle veille-sommeil complètement différent dans un même environnement, selon son stade de récupération. Notre troisième article confirme que la consolidation du cycle veille-sommeil évolue en synchronie avec la récupération de la conscience et des fonctions cognitives dans la phase aiguë du TCC. Notre quatrième article compare le sommeil des patients TCC à celui des blessés orthopédiques graves, sans TCC, en utilisant un système de PSG ambulatoire au chevet. Nous démontrons que, contrairement à notre hypothèse, le sommeil des patients TCC comprend tous les éléments et stades d’un sommeil normal. Cependant, ces patients s’endorment plus tôt et ont un sommeil de plus longue durée, mais plus fragmenté, que les patients sans TCC. Dans les deux groupes, le sommeil est de mauvaise qualité, reflétant probablement l’effet de facteurs non-spécifiques associés avec les blessures physiques et l’environnement hospitalier. Conséquemment, la PSG en phase aiguë permet difficilement de distinguer les patients TCC des patients sans TCC. Notre dernier article confirme que les patients avec TCC ont une consolidation du cycle veille-sommeil et une qualité de sommeil nocturne inférieures à celles des patients sans TCC, ce qui confirme le rôle du TCC dans les perturbations du cycle veille-sommeil. Cependant, malgré ces perturbations plus sévères, les patients TCC ont un rythme normal de la mélatonine et celui-ci n’est pas associé aux perturbations observées. Cet article suggère que des mécanismes neuronaux autres que l’horloge circadienne seraient responsables des perturbations du cycle veille-sommeil à la suite d’un TCC. Cette thèse est la première à évaluer le sommeil et le fonctionnement de l’horloge circadienne de patients hospitalisés avec un TCC modéré ou sévère ayant atteint la stabilité médicale. En isolant le rôle du TCC de celui du traumatisme physique et du milieu hospitalier, ces études contribuent à comprendre les caractéristiques, les conséquences et la pathophysiologie des perturbations du cycle veille-sommeil à la suite d’un TCC, ouvrant la voie à de possibles interventions visant à améliorer le sommeil et optimiser la récupération.Traumatic brain injuries (TBI) are the leading cause of disability among young adults, causing debilitating cognitive, psychological and behavioural impairments. Sleep-wake disturbances (SWD) are among the most persistent sequelae following TBI, and could impede recovery. Indeed, sleep is essential to learning, plasticity and neurogenesis. Clinical observations suggest that these disturbances arise in the first weeks following injury, and could suggest a circadian disturbance. However, no study has yet documented how SWD arise and evolve in the acute phase of TBI, or how they are associated to short-term cognitive and functional recovery. Consequently, this thesis aims to characterize the sleep and circadian rhythms of patients hospitalized with moderate or severe TBI, and determine whether SWD are caused by a deregulation of the circadian clock. To achieve this goal, we used objective and quantitative measures of sleep and circadian rhythms including actigraphy, polysomnography (PSG), and melatonin, beginning in the awakening stage in the Intensive Care Unit. In order to understand the specific role of TBI on SWD, we compared TBI patients to other hospitalized trauma patients, without TBI. Our comprehensive study protocol led to five research articles. First, we show that the sleep-wake cycle of TBI patients is severely disturbed, but improves for 50% of patients during their hospital stay. Patients whose sleep-wake cycle consolidation improves have better cognitive and functional outcome at hospital discharge. Then, in a single case study, we demonstrate how a patient can have drastically different sleep-wake patterns in the same environment, according to recovery stage. In our third research article, we show that the consolidation of sleep and wake states evolves synchronously with the recovery of consciousness and cognition in the acute phase of TBI. Our fourth article compares the sleep of TBI patients to that of non-TBI trauma patients using ambulatory PSG at bedside. Contrary to our hypothesis, TBI patients have normal sleep elements and normal proportions of each sleep stages. However, they have earlier sleep onset and longer nighttime sleep duration, but with greater fragmentation, than non-TBI patients. In both groups, sleep quality is poor, which most likely reflects non-specific factors associated with the physical trauma and hospital environment. Therefore, PSG reveals little information able to distinguish TBI patients from other non-TBI trauma patients at this stage post-injury. Our final article shows that TBI patients have poorer sleep-wake cycle consolidation and nighttime sleep quality than non-TBI patients, confirming the role of the TBI in altering sleep and wake states. However, despite having more severe SWD, TBI patients have a normal melatonin rhythm, and this rhythm is not associated with the observed SWD. This article suggests that neural mechanisms other than the circadian clock may be responsible for post-TBI SWD. This thesis is the first to investigate the sleep and circadian clock of hospitalized moderate to severe TBI patients who are medically stable. By isolating the role of the injured brain from that of overall trauma and the hospital setting, these studies contribute to understanding the characteristics, consequences and pathophysiology of post-TBI SWD, unlocking the possibility to design interventions aiming to improve sleep and optimize recovery

Early Postpartum Awakenings, Neurocognitive Performance, and Feeding Methods

This study investigated memory for brief nocturnal awakenings, characteristics of those awakenings in women during the early and late postpartum period, and how these awakenings were related to neurocognitive performance in exclusively breastfeeding and exclusively formula-feeding mothers.;The median duration of a nocturnal awakening necessary for morning recall was four minutes and 30 seconds, which closely resembles the current five-minute rule of thumb. There was normal variability in thresholds, indicating that other factors may influence memory for awakenings. During the postpartum period, women generally under-reported the number of awakenings experienced each night, but did increase in accuracy by week 12. Average number and duration of awakenings were not related to concurrent neurocognitive performance. There were no differences in number of lapses on the psychomotor vigilance test based on feeding method. However, exclusively formula-feeding mothers did have increased median reaction time overall compared to exclusively breastfeeding mothers, despite no significant differences in average number or duration of awakenings.;Findings from this work increase our basic understanding of memory formation during nocturnal awakenings, as well as how postpartum sleep disturbance changes over time and the associations between infant feeding method and maternal sleep disturbance

The Relationship Between Sleep Disturbances and Episodic Memory in Older Adults.

Impaired episodic memory in older adults has been posited to be related to sleep disturbances which are revealed by self-reported questionnaires and objective devices but the relationship between these two measured results is unclear. Sleep disturbances have been tied to declines in attention, executive function, and cognitive reserve, which may contribute to impaired episodic memory. However, how sleep disturbances relate to these cognitive functions and in turn influence episodic memory remains unclear. Age and depressive symptoms are correlated with sleep disturbances and episodic memory decline in older adults; however, the role of age and depressive symptoms in explaining the relationship between sleep disturbances and episodic memory remains unclear The specific aims were (a) to determine the conceptual structure of sleep disturbances in older adults; and (b) to determine the relationship between sleep disturbances and episodic memory in older adults, including the roles of attention, executive function, cognitive reserve, depressive symptoms, and aging in the relationship. This descriptive study included a convenience sample of (N=62) older adults (age 60-88). Two sleep questionnaires and actigraphy were used to measure sleep; the Hopkins Verbal Learning Test-Revised was used to assess episodic memory; the CogState computerized battery was used to evaluate attention and executive function; and the Wide Range Achievement Test 4-Reading subtest was used to measure cognitive reserve. Descriptive statistics, Pearson’s correlation, exploratory factor analysis, and hierarchical multiple regression analyses were conducted to analyze data. Self-reported sleep disturbances significantly correlated with objective sleep time and wakefulness during sleep periods, but this relationship was only substantial for objective sleep time. In older adults, more objective difficulty in falling and staying asleep, better executive function, more cognitive reserve and unexpectedly, higher level of daytime sleepiness explained better episodic memory after controlling for the covariates. The influence of sleep disturbances on episodic memory was stronger among those participants with more, as compared to less depressive symptoms. The study results suggest some possible directions to develop sleep interventions to prevent episodic memory declines in older adults. Future studies may focus on improving daytime sleepiness and difficulty in falling and staying asleep to prevent episodic memory declines.PhDNursingUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113327/1/anyun_1.pd

Intelligent Bed

Cílem této práce je studium rys fyzické aktivity v denním cyklu "spánek - bdění", stejně jako studium změn spánku pod vlivem vnějších faktorů pomocí vyvinutého hardware - softwarového monitorovacího systému. K dosažení tohoto cíle byly řešeny následující úkoly: 1. Vyhodnocen charakter distribuce fyzické aktivity účastníků studie v noci a ve dne. 2. Byla určena charakteristika motorické aktivity těchto dvou účastníků. 3. Byly vyhodnoceny vztahy změn ukazatelů fyzické aktivity s rostoucími vnějšími ovlivňujícími factory. 4. Byla vyhodnocena účinnost aktigrafie během výzkumu.The purpose of this work is to study features of physical activity in the daily cycle "sleep - wakefulness" as well as changes in sleep under the influence of external factors using developed hardware - software monitoring system. In order to achieve this goal the following tasks were solved: 1. Evaluate the distribution's character of physical activity of the participants of the study at night and daytime. 2. Identify the characteristics of motor activity of these two participants. 3. Evaluate relations of changes of physical activity indicators with increasing external influencing factors. 4. Evaluate the efficiency of actigraphy method during the research

Environment shapes sleep patterns in a wild nocturnal primate

Among primates, the suborder Haplorhini is considered to have evolved a consolidated monophasic sleep pattern, with diurnal species requiring a shorter sleep duration than nocturnal species. Only a few primate species have been systematically studied in their natural habitat where environmental variables, including temperature and light, have a major influence on sleep and activity patterns. Here we report the first sleep study on a nocturnal primate performed in the wild. We fitted seven wild Javan slow lorises (Nycticebus javanicus) in West Java, Indonesia with accelerometers that collected activity data, and installed climate loggers in each individual's home range to collect ambient temperature readings (over 321 days in total). All individuals showed a strictly nocturnal pattern of activity and displayed a striking synchronisation of onset and cessation of activity in relation to sunset and sunrise. The longest consolidated rest episodes were typically clustered near the beginning and towards the end of the light period, and this pattern was inversely related to daily fluctuations of the ambient temperature. The striking relationship between daily activity patterns, light levels and temperature suggests a major role of the environment in shaping the daily architecture of waking and sleep. We concluded that well-known phenotypic variability in daily sleep amount and architecture across species may represent an adaptation to changes in the environment. Our data suggest that the consolidated monophasic sleep patterns shaped by environmental pressures observed in slow lorises represent phylogenetic inertia in the evolution of sleep patterns in humans

Non-Contact Sleep Monitoring

"The road ahead for preventive medicine seems clear. It is the delivery of high quality, personalised (as opposed to depersonalised) comprehensive medical care to all." Burney, Steiger, and Georges (1964) This world's population is ageing, and this is set to intensify over the next forty years. This demographic shift will result in signicant economic and societal burdens (partic- ularly on healthcare systems). The instantiation of a proactive, preventative approach to delivering healthcare is long recognised, yet is still proving challenging. Recent work has focussed on enabling older adults to age in place in their own homes. This may be realised through the recent technological advancements of aordable healthcare sen- sors and systems which continuously support independent living, particularly through longitudinally monitoring deviations in behavioural and health metrics. Overall health status is contingent on multiple factors including, but not limited to, physical health, mental health, and social and emotional wellbeing; sleep is implicitly linked to each of these factors. This thesis focusses on the investigation and development of an unobtrusive sleep mon- itoring system, particularly suited towards long-term placement in the homes of older adults. The Under Mattress Bed Sensor (UMBS) is an unobstrusive, pressure sensing grid designed to infer bed times and bed exits, and also for the detection of development of bedsores. This work extends the capacity of this sensor. Specically, the novel contri- butions contained within this thesis focus on an in-depth review of the state-of-the-art advances in sleep monitoring, and the development and validation of algorithms which extract and quantify UMBS-derived sleep metrics. Preliminary experimental and community deployments investigated the suitability of the sensor for long-term monitoring. Rigorous experimental development rened algorithms which extract respiration rate as well as motion metrics which outperform traditional forms of ambulatory sleep monitoring. Spatial, temporal, statistical and spatiotemporal features were derived from UMBS data as a means of describing movement during sleep. These features were compared across experimental, domestic and clinical data sets, and across multiple sleeping episodes. Lastly, the optimal classier (built using a combina- tion of the UMBS-derived features) was shown to infer sleep/wake state accurately and reliably across both younger and older cohorts. Through long-term deployment, it is envisaged that the UMBS-derived features (in- cluding spatial, temporal, statistical and spatiotemporal features, respiration rate, and sleep/wake state) may be used to provide unobtrusive, continuous insights into over- all health status, the progression of the symptoms of chronic conditions, and allow the objective measurement of daily (sleep/wake) patterns and routines

Expression of interferon-inducible chemokines and sleep/wake changes during early encephalitis in experimental African trypanosomiasis

Background: Human African trypanosomiasis or sleeping sickness, caused by the parasite Trypanosoma brucei, leads to neuroinflammation and characteristic sleep/wake alterations. The relationship between the onset of these alterations and the development of neuroinflammation is of high translational relevance, but remains unclear. This study investigates the expression of interferon (IFN)-γ and IFN-inducible chemokine genes in the brain, and the levels of CXCL10 in the serum and cerebrospinal fluid prior to and during the encephalitic stage of trypanosome infection, and correlates these with sleep/wake changes in a rat model of the disease. Methodology/Principal findings: The expression of genes encoding IFN-γ, CXCL9, CXCL10, and CXCL11 was assessed in the brain of rats infected with Trypanosoma brucei brucei and matched controls using semi-quantitative end-point RT-PCR. Levels of CXCL10 in the serum and cerebrospinal fluid were determined using ELISA. Sleep/wake states were monitored by telemetric recording. Using immunohistochemistry, parasites were found in the brain parenchyma at 14 days post-infection (dpi), but not at 6 dpi. Ifn-γ, Cxcl9, Cxcl10 and Cxcl11 mRNA levels showed moderate upregulation by 14 dpi followed by further increase between 14 and 21 dpi. CXCL10 concentration in the cerebrospinal fluid increased between 14 and 21 dpi, preceded by a rise in the serum CXCL10 level between 6 and 14 dpi. Sleep/wake pattern fragmentation was evident at 14 dpi, especially in the phase of wake predominance, with intrusion of sleep episodes into wakefulness. Conclusions/Significance: The results show a modest increase in Cxcl9 and Cxcl11 transcripts in the brain and the emergence of sleep/wake cycle fragmentation in the initial encephalitic stage, followed by increases in Ifn-γ and IFN-dependent chemokine transcripts in the brain and of CXCL10 in the cerebrospinal fluid. The latter parameter and sleep/wake alterations could provide combined humoral and functional biomarkers of the early encephalitic stage in African trypanosomiasis

The Impact of Subthalamic Deep Brain Stimulation on Sleep–Wake Behavior: A Prospective Electrophysiological Study in 50 Parkinson Patients

Study objectives: This prospective observational study was designed to systematically examine the effect of subthalamic deep brain stimulation (DBS) on subjective and objective sleep-wake parameters in Parkinson patients. Methods: In 50 consecutive Parkinson patients undergoing subthalamic DBS, we assessed motor symptoms, medication, the position of DBS electrodes within the subthalamic nucleus (STN), subjective sleep-wake parameters, 2-week actigraphy, video-polysomnography studies, and sleep electroencepahalogram frequency and dynamics analyses before and 6 months after surgery. Results: Subthalamic DBS improved not only motor symptoms and reduced daily intake of dopaminergic agents but also enhanced subjective sleep quality and reduced sleepiness (Epworth Sleepiness Scale: -2.1 ± 3.8, p < .001). Actigraphy recordings revealed longer bedtimes (+1:06 ± 0:51 hours, p < .001) without shifting of circadian timing. Upon polysomnography, we observed an increase in sleep efficiency (+5.2 ± 17.6%, p = .005) and deep sleep (+11.2 ± 32.2 min, p = .017) and increased accumulation of slow-wave activity over the night (+41.0 ± 80.0%, p = .005). Rapid eye movement sleep features were refractory to subthalamic DBS, and the dynamics of sleep as assessed by state space analyses did not normalize. Increased sleep efficiency was associated with active electrode contact localization more distant from the ventral margin of the left subthalamic nucleus. Conclusion: Subthalamic DBS deepens and consolidates nocturnal sleep and improves daytime wakefulness in Parkinson patients, but several outcomes suggest that it does not normalize sleep. It remains elusive whether modulated activity in the STN directly contributes to changes in sleep-wake behavior, but dorsal positioning of electrodes within the STN is linked to improved sleep-wake outcomes