A method for calculating vector forces at human-mattress interface during sleeping positions utilizing image registration.

The vector forces at the human-mattress interface are not only crucial for understanding the distribution of vertical and shear forces exerted on the human body during sleep but also serves as a significant input for biomechanical models of sleeping positions, whose accuracy determines the credibility of predicting musculoskeletal system loads. In this study, we introduce a novel method for calculating the interface vector forces. By recording indentations after supine and lateral positions using a vacuum mattress and 3D scanner, we utilize image registration techniques to align body pressure distribution with the mattress deformation scanning images, thereby calculating the vector force values for each unit area (36.25 mm × 36.25 mm). This method was validated through five participants attendance from two perspectives, revealing that (1) the mean summation of the vertical force components is 98.67% ± 7.21% body weight, exhibiting good consistency, and mean ratio of horizontal component force to body weight is 2.18% ± 1.77%. (2) the predicted muscle activity using the vector forces as input to the sleep position model aligns with the measured muscle activity (%MVC), with correlation coefficient over 0.7. The proposed method contributes to the vector force distribution understanding and the analysis of musculoskeletal loads during sleep, providing valuable insights for mattress design and evaluation.

Heart rate detection method based on Ballistocardiogram signal of wearable device：Algorithm development and validation.

Background: Heart rate, as the four vital signs of human body, is a basic indicator to measure a person's health status. Traditional electrocardiography (ECG) measurement, which is routinely monitored, requires subjects to wear lead electrodes frequently, which undoubtedly places great restrictions on participants' activities during the normal test. At present, the boom of wearable devices has created hope for non-invasive, simple operation and low-cost daily heart rate monitoring, among them, Ballistocardiogram signal (BCG) is an effective heart rate measurement method, but in the actual acquisition process, the robustness of non-invasive vital sign collection is limited. Therefore, it is necessary to develop a method to improve the robustness of heart rate monitoring. Objective: Therefore, in view of the problem that the accuracy of untethered monitoring heart rate is not high, we propose a method aimed at detecting the heartbeat cycle based on BCG to accurately obtain the beat-to-beat heart rate in the sleep state. Methods: In this study, we implement an innovative J-wave detection algorithm based on BCG signals. By collecting BCG signals recorded by 28 healthy subjects in different sleeping positions, after preprocessing, the data feature set is formed according to the clustering of morphological features in the heartbeat interval. Finally, a J-wave recognition model is constructed based on bi-directional long short-term memory (BiLSTM), and then the number of J-waves in the input sequence is counted to realize real-time detection of heartbeat. The performance of the proposed heartbeat detection scheme is cross-verified, and the proposed method is compared with the previous wearable device algorithm. Results: The accuracy of J wave recognition in BCG signal is 99.67%, and the deviation rate of heart rate detection is only 0.27%, which has higher accuracy than previous wearable device algorithms. To assess consistency between method results and heart rates obtained by the ECG, seven subjects are compared using Bland-Altman plots, which show no significant difference between BCG and ECG results for heartbeat cycles. Conclusions: Compared with other studies, the proposed method is more accurate in J-wave recognition, which improves the accuracy and generalization ability of BCG-based continuous heartbeat cycle extraction, and provides preliminary support for wearable-based untethered daily monitoring.

A prematuridade afeta as práticas maternas brasileiras relacionadas ao posicionamento de lactentes? / Does premature birth affect Brazilian parents' practices related to infant positioning?

Abstract Objective: To verify whether the time spent in prone, supine, or seated positions differed between term and preterm infants; and to determine whether a single verbal guidance session for parents changed the time spent in different positions, and, consequently, the motor development scores, after one month in preterm infants. Methods: Sixty-one infants from a full-term and preterm group from Brazil were included. Motor development was assessed by the Alberta Infant Motor Scale (AIMS) and the parents registered the time spent in each position on a 24-hour schedule. A month after verbal guidance, a second assessment was performed only on the preterm infants. Results: The positioning times awake determined for the full-term and preterm parents were similar. Preterm infants spent more time in the prone sleeping position (2.1 vs. 0.8 h; p=0.037) than full-term infants. The AIMS percentile scores did not differ significantly between the groups. For preterm infants, the time spent in all positions did not change during the second assessment (n=18). Conclusions: The fact that some parents position their infants in the prone posture during sleeping periods reinforce the importance of parental education approaches for sudden infant death syndrome (SIDS) prevention during the first months of life. The verbal guidance provided to parents of preterm infants did not influence the AIMS percentile and time spent in various positions but increased preterm parents' confidence in placing their infants in a prone position to play.

RESUMO Objetivo: Verificar se o tempo nas posições prono, supino ou sentado difere entre lactentes a termo e pré-termo; bem como determinar se uma única sessão de orientação verbal aos pais alterou o tempo despendido nas diferentes posições e, consequentemente, o escore de desenvolvimento motor, após um mês em lactentes pré-termo. Métodos: Foram incluídos 61 lactentes brasileiros nos grupos a termo e pré-termo. O desenvolvimento motor foi avaliado pela Alberta Infant Motor Scale (AIMS), e os pais registraram o tempo despendido em cada posição em uma linha do tempo de 24 horas. Um mês após a orientação verbal, uma segunda avaliação foi realizada apenas nos lactentes pré-termo. Resultados: O tempo de posicionamento acordado determinado pelos pais de lactentes a termo e pré-termo foi semelhante. Os lactentes pré-termo passaram mais tempo dormindo na posição prona (2,2 vs. 0,8 h; p=0,037) do que os lactentes a termo. Os escores de percentil AIMS não diferiram significativamente entre os grupos. Para lactentes pré-termo, o tempo despendido em todas as posições não se modificou durante a segunda avaliação (n=18). Conclusões: O fato de alguns pais posicionarem os lactentes em decúbito ventral durante os períodos de sono reforça a importância das abordagens educativas parentais para a prevenção da síndrome da morte súbita do lactente (SMSL) durante os primeiros meses de vida. A orientação verbal fornecida aos pais de prematuros não influenciou o percentil da AIMS e o tempo de permanência em várias posições, mas aumentou a confiança dos pais de lactentes prematuros em utilizar a posição prona para brincar.

Effect of sleeping position on cardiac output, pulmonary pressure, and superior vena cava flow in healthy term infants.

BACKGROUND: Although the mechanism of action in newborns is unknown, sleep positioning is associated with many pathophysiological events. This study aimed to compare the effects of supine and prone sleeping positions on cardiac output (CO), systolic pulmonary arterial pressure (SPAP), and superior vena cava (SVC) flow in healthy newborns. METHODS: In the first 24-72 h of life, 40 healthy term newborns born in the same hospital were included in this prospective, cross-sectional, observational study. CO, SVC flow, and SPAP values of newborns in the supine and prone sleeping positions were calculated using echocardiographic examination. The measurements were statistically compared. RESULTS: In the supine sleeping position, CO, SVC flow, and SPAP were 235.00 (193.07-283.30) ml/kg/min, 92.80 (77.82-121.87) ml/kg/min, and 27.85 (24.70-30.48) mmHg. In the prone sleeping position, CO, SVC flow, and SPAP were measured as 195.35 (166.00-229.40) ml/kg/min, 67.25 (51.82-96.66) ml/kg/min, 31.60 (28.45-37.20) mmHg, respectively. Depending on sleeping position, these variables were significantly different between the groups. CONCLUSION: SVC flow and CO decreased in the prone sleeping position compared to the supine sleeping position in healthy newborns, whereas SPAP increased. The different hemodynamic effects of sleeping position on the cardiac, pulmonary, and nervous systems should be considered as flow and pressure changes are important in newborns.

Involvement of the Superior Colliculus in SIDS Pathogenesis.

The aim of this study was to investigate the involvement of the mesencephalic superior colliculus (SC) in the pathogenetic mechanism of SIDS, a syndrome frequently ascribed to arousal failure from sleep. We analyzed the brains of 44 infants who died suddenly within the first 7 months of life, among which were 26 infants with SIDS and 18 controls. In-depth neuropathological investigations of serial sections of the midbrain showed the SC layered cytoarchitectural organization already well known in animals, as made up of seven distinct layers, but so far never highlighted in humans, albeit with some differences. In 69% of SIDS cases but never in the controls, we observed alterations of the laminar arrangement of the SC deep layers (precisely, an increased number of polygonal cells invading the superficial layers and an increased presence of intensely stained myelinated fibers). Since it has been demonstrated in experimental studies that the deep layers of the SC exert motor control including that of the head, their developmental disorder could lead to the failure of newborns who are in a prone position to resume regular breathing by moving their heads in the sleep-arousal phase. The SC anomalies highlighted here represent a new step in understanding the pathogenetic process that leads to SIDS.

The Practice of Infant Sleep Position among Mothers in Jimma Town Public Health Institutions, Jimma, Oromia, South West Ethiopia, 2022.

Background: One of the important interventions in the infantile period is the selection of appropriate infant sleeping position. Unsafe infant sleep position is associated with sudden unexpected death in infancy. Yet, little is known about the practice of infant sleep position in Ethiopia. This study aimed to assess the practice of infant sleep position among mothers attending mother and child health service in Jimma town public health institutions, South West Ethiopia, 2022. Methods: An institutional based cross-sectional study design was conducted on 409 women attending Maternal and child health service in Jimma town public health facilities. The data were collected using a pre-tested and semi- structured questionnaire. Binary Logistic regression was used to analyze the association between the practice infant sleeping positions and explanatory variables. The strength of association was evaluated using an odds ratio at a 95% confidence interval and a P-value ≤ .05 was considered to declare significant associations. Results: Four hundred nine women participated in the study, with a response rate of 97%. The practice of recommended infant sleeping position (supine position) in this study was 33.5% [95% CI (28.9% - 38.6%)]. Being married Adjusted odds ratio (AOR) 2.6; 95% CI (1.04-6.48)), residence (AOR 1.88; 95% CI (1.1-3.31)) multi gravidity (AOR 1.6; 95% CI (1.02-2.59)) and having good knowledge of sleeping position (AOR 1.55; 95% CI (1.01-2.38)) were significantly associated with the practice of infant sleep position. Conclusion: The practice of medically recommended infant sleep position in this study was low. Being married, residence, multi gravidity and having good knowledge of sleeping position were significantly associated with the practice of infant sleep position. Therefore, considering these associated factors during health care provision and disseminating information on safe sleep practices for mothers is needed. Also, different stakeholders, including the federal ministry of health, health professionals, and health institutions at different levels, need to give attention to such problems in addition to the service to reduce infant mortality.

Does premature birth affect Brazilian parents' practices related to infant positioning? / A prematuridade afeta as práticas maternas brasileiras relacionadas ao posicionamento de lactentes?

Abstract Objective: To verify whether the time spent in prone, supine, or seated positions differed between term and preterm infants; and to determine whether a single verbal guidance session for parents changed the time spent in different positions, and, consequently, the motor development scores, after one month in preterm infants. Methods: Sixty-one infants from a full-term and preterm group from Brazil were included. Motor development was assessed by the Alberta Infant Motor Scale (AIMS) and the parents registered the time spent in each position on a 24-hour schedule. A month after verbal guidance, a second assessment was performed only on the preterm infants. Results: The positioning times awake determined for the full-term and preterm parents were similar. Preterm infants spent more time in the prone sleeping position (2.1 vs. 0.8 h; p=0.037) than full-term infants. The AIMS percentile scores did not differ significantly between the groups. For preterm infants, the time spent in all positions did not change during the second assessment (n=18). Conclusions: The fact that some parents position their infants in the prone posture during sleeping periods reinforce the importance of parental education approaches for sudden infant death syndrome (SIDS) prevention during the first months of life. The verbal guidance provided to parents of preterm infants did not influence the AIMS percentile and time spent in various positions but increased preterm parents' confidence in placing their infants in a prone position to play.

RESUMO Objetivo: Verificar se o tempo nas posições prono, supino ou sentado difere entre lactentes a termo e pré-termo; bem como determinar se uma única sessão de orientação verbal aos pais alterou o tempo despendido nas diferentes posições e, consequentemente, o escore de desenvolvimento motor, após um mês em lactentes pré-termo. Métodos: Foram incluídos 61 lactentes brasileiros nos grupos a termo e pré-termo. O desenvolvimento motor foi avaliado pela Alberta Infant Motor Scale (AIMS), e os pais registraram o tempo despendido em cada posição em uma linha do tempo de 24 horas. Um mês após a orientação verbal, uma segunda avaliação foi realizada apenas nos lactentes pré-termo. Resultados: O tempo de posicionamento acordado determinado pelos pais de lactentes a termo e pré-termo foi semelhante. Os lactentes pré-termo passaram mais tempo dormindo na posição prona (2,2 vs. 0,8 h; p=0,037) do que os lactentes a termo. Os escores de percentil AIMS não diferiram significativamente entre os grupos. Para lactentes pré-termo, o tempo despendido em todas as posições não se modificou durante a segunda avaliação (n=18). Conclusões: O fato de alguns pais posicionarem os lactentes em decúbito ventral durante os períodos de sono reforça a importância das abordagens educativas parentais para a prevenção da síndrome da morte súbita do lactente (SMSL) durante os primeiros meses de vida. A orientação verbal fornecida aos pais de prematuros não influenciou o percentil da AIMS e o tempo de permanência em várias posições, mas aumentou a confiança dos pais de lactentes prematuros em utilizar a posição prona para brincar.

The Relationship between Sleeping Position and Sleep Quality: A Flexible Sensor-Based Study.

The use of flexible wearable sensors to monitor the impact of sleeping position and turning frequency on sleep and to study sleep patterns can help bedridden patients heal and recover. The flexible wearable sleeping-position monitoring device was designed and developed using a flexible angle sensor and a six-axis motion sensor to measure the dynamic changes in body posture during sleep. Based on the changes in the output parameters of the flexible angle sensor and the six-axis motion sensor, we determined the change in the subject's lying position, verifying and analyzing the relationship between lying position preference, turning frequency, and sleep quality in healthy subjects. The sleeping-position monitoring device was worn by 13 subjects (7 males and 6 females) without sleep disorders before the sleep experiment. They performed more than 50 sleeping-position changes to ensure the accuracy of the monitoring device. Subjects slept in their beds for 8 h per night for 15 nights. During that time, they wore the sleeping-position monitoring device and a wristband sleep-monitoring bracelet on their left hand, and gathered the subjective sleep data using questionnaires. The results show that the most critical influencing factors are sleeping-position preference and frequency of turning. Data analysis reveals that subjects with a preference for right-sided lying and a lower frequency of turning had better sleep quality.

US county-level estimation for maternal and infant health-related behavior indicators using pregnancy risk assessment monitoring system data, 2016-2018.

BACKGROUND: There is a critical need for maternal and child health data at the local level (for example, county), yet most counties lack sustainable resources or capabilities to collect local-level data. In such case, model-based small area estimation (SAE) could be a feasible approach. SAE for maternal or infant health-related behaviors at small areas has never been conducted or evaluated. METHODS: We applied multilevel regression with post-stratification approach to produce county-level estimates using Pregnancy Risk Assessment Monitoring System (PRAMS) data, 2016-2018 (n = 65,803 from 23 states) for 2 key outcomes, breastfeeding at 8 weeks and infant non-supine sleeping position. RESULTS: Among the 1,471 counties, the median model estimate of breastfeeding at 8 weeks was 59.8% (ranged from 34.9 to 87.4%), and the median of infant non-supine sleeping position was 16.6% (ranged from 10.3 to 39.0%). Strong correlations were found between model estimates and direct estimates for both indicators at the state level. Model estimates for both indicators were close to direct estimates in magnitude for Philadelphia County, Pennsylvania. CONCLUSION: Our findings support this approach being potentially applied to other maternal and infant health and behavioral indicators in PRAMS to facilitate public health decision-making at the local level.

Trends in infant mortality: an evaluation of forensic autopsied infants in Eastern Denmark over 39 years.

BACKGROUND: SIDS is a diagnosis of exclusion applied to the death of an infant < 1 year of age after an extensive post-mortem investigation. From 1980 to 2018, a total of 870 infants have been autopsied at the Section of Forensic Pathology, Department of Forensic Medicine, UCPH, covering East Denmark. In the same period, Danish national guidelines for infant care have been revised to avoid infants dying of SIDS. OBJECTIVE: This study aimed to describe trends in infant autopsies regarding cause and manner of death, gender, age, month of death, sleeping position, and bed-sharing. The trends were compared to the change in national SIDS guidelines during the period of this study. DESIGN: Information from autopsy reports from 1980 to 2018 were collected into 55 categories designed specifically for this study. Data from 7 of these categories were chosen and processed in Excel for basic epidemiological comparison. RESULTS: The trends show that most infants in the study die of natural manner and most predominant causes of death are SIDS, infection, and congenital malformations. A change in national guidelines in 1991 recommending supine- or side sleeping position coincided with a reduction in the overall infant mortality and cases of SIDS. The peak age in the cohort is 90 days, but stratification in decades shows the infants dying younger each decade. Through the study period, the number of infants found dead sleeping in the prone position has declined. Relatively more infants in this cohort have been found dead while bed-sharing, even though the prevalence of these cases has remained largely the same for four decades.

The effect of body position on maternal cardiovascular function during sleep and wakefulness in late pregnancy.

INTRODUCTION: An association between the increased risk of late stillbirth and the maternal supine sleeping position has been recently established. The risk of stillbirth following supine sleep has been suspected to occur as a result of aortocaval compression by the gravid uterus. A number of studies conducted during wakefulness have reported compromised cardiovascular function during supine rest, as demonstrated by reductions in cardiac output, blood pressure and utero-placental blood flow. It remains unclear whether similar effects are also present during sleep, due to the presence of key sleep-specific changes in cardiovascular function. OBJECTIVE: To investigate the changes in maternal cardiovascular function between the supine and left-lateral positions during wakefulness and non-rapid eye movement (NREM) sleep in late pregnancy. METHODS: Twenty-nine women with a singleton pregnancy between 24.7 and 36.7 weeks' gestation participated in a single overnight sleep study. Physiological measures (blood pressure, heart rate, heart rate variability - HRV, and pulse arrival time - PAT) were measured and recorded throughout the night using standard polysomnography equipment and the Portapres Model-2 device. As the present study evaluated cardiovascular changes during natural rest and sleep in pregnancy, participants were not given explicit instructions on which position to adopt. Body position was continuously recorded using a position monitor and verified with video recording. RESULTS: No changes in systolic, diastolic or mean arterial blood pressure were observed between the left-lateral and supine positions during wakefulness or sleep. However, heart rate was significantly higher in the supine position compared to the left during wakefulness (p= .03), with a similar trend present during sleep (p= .11). A significantly shorter PAT was measured in the supine position (compared to the left) during wakefulness (p= .01) and sleep (p= .01). No change in HRV measures was observed between the left and supine positions in either state. CONCLUSION: Blood pressure did not appear to differ significantly between the left-lateral and supine positions during wakefulness and sleep. The lack of blood pressure differences may reflect elevated sympathetic activity during rest and sleep in the supine position (compared to the left), suggesting that some degree of compensation for aortocaval compression may still be possible during sleep.

Standardized framework to report on the role of sleeping position in sleep apnea patients.

PURPOSE: Sleep apnea is a multifactorial illness which can be differentiated in various physiological phenotypes as a result of both anatomical and non-anatomical contributors (e.g., low respiratory arousal threshold, high loop gain). In addition, the frequency and duration of apneas, in the majority of patients with OSA, are influenced by sleeping position. Differences in characteristics between non-positional patients (NPP) and positional patients (PP) suggest another crucial phenotype distinction, a clinical phenotype focusing on the role of sleeping position on sleep apnea. Since this clinical phenotype distinction has therapeutic implications, further research is necessary to better understand the pathophysiology behind this phenotypic trait and to improve management of PP. Therefore, we suggest a standardized framework that emphasizes the role of sleeping position when reporting clinical and research data on sleep apnea. METHODS: We identified 5 key topics whereby a standardized framework to report on the role of sleeping position would be of added value: (1) sleep study data, (2) anatomical, morphological and physiological factors, (3) drug-induced sleep endoscopy (DISE) findings, (4) sleep apnea management, and (5) effectiveness versus efficacy of positional therapy in sleep apnea management. We performed a literature search to identify evidence to describe and support the rationale behind these 5 main recommendations. RESULTS: In this paper, we present the rationale behind this construct and present specific recommendations such as reporting sleep study indices (disease severity) and sleep time spent in various sleeping positions. The same is suggested for DISE findings and effect of treatment. Sleep study indices (disease severity), anatomical, morphological, and physiological factors in sleep apnea patients should be reported separately for PP and NPP. CONCLUSION: Applying these suggestions in future research will improve patient care, assist in better understanding of this dominant phenotype, and will enhance accurate comparisons across studies and future investigations.

Maternal intentions towards infant sleeping practices in Ireland.

AIM: Mortality from Sudden Infant Death Syndrome (SIDS) has reduced by 50%-85% globally. Despite improvements from 1990 to 2009, the Irish SIDS rate has plateaued. Reasons for this are unclear, but may be related to a reduced parental SIDS awareness. Our study aimed to assess intentions regarding infant sleeping practices in mothers in Ireland. METHODS: A cross-sectional survey of post-partum mothers was performed in the Rotunda Hospital over a four month period. Mothers with a history of SIDS, miscarriage or neonatal admissions were excluded. RESULTS: Of 451 participants, unsafe sleeping positions were intended by 15.4%, reduced by Irish ethnicity [AOR = 0.52, 95% CI = 0.277-0.959, P = .036]. Safe sleep locations were intended by 66%, increased by Irish ethnicity [AOR = 2.6, 95% CI = 1.617-4.191, P < .001], and reduced by young maternal age [AOR = 0.15, 95% CI = 0.03-0.713, P = .02]. Maternal smoking was more likely in mothers with lower educational level [AOR = 3.51, 95% CI = 1.169-10.56, P = .03]. Soft bedding use was intended by 34.8%, increased in younger mothers [AOR = 2.28, 95% CI = 1.04-4.98, P = .04]. Breastfeeding was intended by 72.2%, decreased by Irish ethnicity [AOR = 0.14, 95% CI = 0.067-0.271, P < .001], and low maternal education [AOR = 0.22, 95% CI = 0.117-0.406, P < .001]. CONCLUSION: Educational campaigns on safe sleep for infants in Ireland need to address modifiable SIDS risks factors, focusing on younger, non-Irish mothers, with lower educational attainment.

Swedish survey of infant sleep practices showed increased bed-sharing and positive associations with breastfeeding.

AIM: Many countries lack monitoring of infant sleep practices, despite associations with sudden infant death. We studied sleep positions, bed-sharing and breastfeeding in a new birth cohort. METHODS: Data were obtained from a prospective, population-based cohort study of children born in western Sweden in 2018. The parents of 9,465 six-month-old infants, via postal questionnaires, were asked about their infants' sleeping positions at three and six months, including where they slept and any bed-sharing arrangements. The data were compared with our earlier 2003-2004 birth cohort. RESULTS: Questionnaires were completed by the parents of 3,590 (38%) infants. At three months, 54% of the infants slept in a separate cot in their parents' room. A further 43% slept in their parents' bed: 42% in baby nests and 42% in close contact with their parents. At six months, 33% bed-shared, compared with 20% in 2003-2004 (p < 0.001). Bed-sharing was positively associated with breastfeeding (odds ratio at three months: 1.5-2.8, 95% confidence interval: 1.1-4.5). CONCLUSION: Most infants slept in separate cots during the first three months. However, bed-sharing showed an increasing trend and baby nests were popular. Bed-sharing was positively associated with breastfeeding, but the association may not be causal.

Incorrect sleeping position and eye rubbing in patients with unilateral or highly asymmetric keratoconus: a case-control study.

PURPOSE: To evaluate eye rubbing and sleeping position in patients with Unilateral or Highly Asymmetric Keratoconus (UHAKC). METHODS: Case-control study of consecutive UHAKC patients diagnosed at the Rothschild Foundation. Controls were age- and sex-matched, randomly selected refractive surgery clinic patients. Patients self-administered questionnaires regarding their family history of keratoconus, eye rubbing, and sleeping habits. All the eyes underwent a comprehensive ocular examination. Logistic regression was used to analyze univariate and multivariate data to identify risk factors for keratoconus. RESULTS: Thirty-three UHAKC patients and 64 controls were included. Univariate analyses showed that daytime eye rubbing [OR = 172.78], in the morning [OR = 24.3], or in eyes with the steepest keratometry [OR = 21.7] were significantly different between groups. Allergy [OR = 2.94], red eyes in the morning [OR = 6.36], and sleeping on stomach/sides [OR = 14.31] or on the same side as the steepest keratometry [OR = 94.72] were also significantly different. The multivariate model also showed statistical significance for most factors including daytime eye rubbing [OR = 134.96], in the morning [OR = 24.86], in the steepest eye [OR = 27.56], and sleeping on stomach/sides [OR = 65.02] or on the steepest side [OR = 144.02]. A univariate analysis in UHAKC group, comparing the worse and better eye, showed that eye rubbing [OR = 162.14] and sleeping position [OR = 99.74] were significantly (p < 0.001) associated with the worse eye. CONCLUSION: Our data suggests that vigorous eye rubbing and incorrect sleeping position are associated with UHAKC. This is especially true in rubbing the most afflicted eye, and contributory sleep position, including positions placing pressure on the eye with the steepest keratometry.

Impact of sleeping position, gravitational force & effective tissue stiffness on obstructive sleep apnoea.

Accurate prediction of deformation and collapse of the upper airway during breathing is required for effective and personalised treatment of obstructive sleep apnoea (OSA). While numerical modelling techniques such as fluid-structure interaction (FSI) are promising, an outstanding challenge is to accurately predict the deformation of the airway during breathing and thus the occurrence of OSA. These difficulties arise because the effective stiffness of the soft tissue in the human upper airway varies due to neuromuscular effects on the stiffness of the underlying muscles. In addition, both the elasticity and anisotropy of the soft tissues along the upper airway are poorly characterised. Finally, gravitational effects on anatomic features are yet to be considered. In this study, a validated FSI technique is introduced that allows prediction of the extent and position of the major deformation in the upper airway. This technique is used to analyse the behaviour of the upper airway in the two most common sleeping positions and for a range of effective tissue stiffnesses. The results demonstrate that sleeping position, gravity and soft tissue stiffness (used here as a proxy for neuromuscular effects) are the main factors that affect upper airway collapse. Therefore, this study provides new insights into the mechanisms of OSA and a new methodology that significantly advances the patient-specific treatment of OSA.

Impaired ability to turn in bed in parkinson's disease as a potential rare cause of positional asphyxia: a sensor-based analysis.

BACKGROUND: Nocturnal hypokinesia commonly affects Parkinson's disease (PD) patients, manifesting primarily as an impaired ability to turn in bed and sleeping in specific positions, such as prone that potentially poses the risk of positional asphyxia. OBJECTIVE: To objectively evaluate, using axial inertial sensors (the NIGHT-Recorder), the ability of PD patients and controls to turn in bed from prone to supine position and to correlate these parameters with disease severity scores. PATIENTS AND METHODS: Turning in bed from prone to supine position was assessed in 16 PD patients with a moderate disease stage and 16 age-matched controls using the NIGHT-Recorder. Successful turning was defined as a full 180 ° turn from prone to supine position as evidenced by the NIGHT-Recorder. Objective parameters included duration, velocity, and acceleration of turn. The ability to turn in bed was determined by torque per kilogram body weight (T/kg). RESULTS: Two out of 16 PD patients (12.5%) could not initiate their turns. PD patients turned with a significant longer duration (p = 0.04), slower velocity (p = 0.04), and acceleration (p = 0.04) compared to controls. Although PD patients had lower T/kg than controls, the difference was not significant. Several significant correlations were demonstrated between turning parameters and clinical rating scales (Duration vs. UPDRS axial: r=0.51, p = 0.04; T/kg vs. PDSS-2: r=0.53, p = 0.03; T/kg vs. NHQ: r=0.52, p = 0.03). CONCLUSION: Our study provides objective evidence of impaired turning in bed from prone to supine position in PD patients with nocturnal hypokinesia. Appropriate measures should be taken to improve nocturnal mobility in those at risk.

A Survey of Koreans on Sleep Habits and Sleeping Symptoms Relating to Pillow Comfort and Support.

The number of people who complain of sleep disturbances is steadily increasing. An understanding of sleep-related factors is required to address sleep problems. This survey study investigated the sleep habits and sleeping symptoms relating to the comfort and support characteristics of pillows and the relationship between sleep quality and pillow design factors. The study utilized data from 332 participating Korean adults aged 20-76 years (mean age ± SD: males, 40.4 ± 15.2; females, 42.9 ± 15.4). We developed a questionnaire that evaluated sleep habits (sleep duration, bedtime, wake-up time and sleeping position); sleeping symptoms (snoring or coughing, breathing and sleepiness during waking hours) based on the Korean version of the Pittsburgh Sleep Quality Index (PSQI-K) questionnaire; and pillow-related factors (support, comfort, fatigue, height and shape) from existing pillow studies. The average sleep duration was 6.8 h, with more than half (52%) of participants sleeping in the supine position. The overall score for sleep quality was considered poor (4.84 points on a seven-point Likert scale), with some degree of sleepiness during waking hours (4.4 points on a seven-point Likert scale). Females went to bed earlier than males and were more likely to sleep in the lateral position compared to males. The number of toss and turn or waking events during sleep increased with age, and older individuals went to sleep earlier and woke up earlier. Among the symptoms of fatigue, pain, discomfort with changing position, snoring, coughing and breathing discomfort, participants reported their highest levels of discomfort due to sleepiness after waking, and they experienced the least head pain. Participants who used a regular-type pillow had poorer satisfaction on multiple comfort and support factors (support, comfort, height suitability, shape suitability) compared with those who used a functional-type pillow. Less head fatigue, less neck fatigue and less shoulder pain had significant effects on sleep quality. To reduce neck fatigue and shoulder pain, designers should consider the height for neck support in the lateral position. To reduce neck fatigue, it is desirable to use materials like latex or memory foam that provide neck support, which can improve sleep quality. The findings of this study contribute to a better understanding of sleep habits and characteristics of pillow comfort and provide practical guidelines for better pillow designs.

Is prone sleeping dangerous for neonates? Polysomnographic characteristics and NDN gene analysis.

OBJECTIVE: Prone sleep is an identified risk factor for sudden infant death syndrome, possibly due to reduced blood pressure, cerebral oxygenation, and impaired cerebral vascular control. Cardiac and respiratory responses in neonates during supine and prone sleep have not been reported. MATERIALS AND METHODS: In this study, daytime polysomnography (PSG) data from 17 neonates aged 2-3 days during supine and prone sleep were reported and the NDN gene, an important gene for neonatal respiratory control, was sequenced for correlation with neonatal respiratory parameters. Heart rate (HR), oxygen saturation, carbon dioxide concentration, sleep stages, central apnea index (CAI), obstructive apnea/hypopnea index (OAHI), and oxygen nadir were compared between supine and prone sleep and between participants with different single-nucleotide polymorphisms (SNPs) in the NDN gene. RESULTS: During prone sleep, neonates had a faster HR, decreased oxygen saturation, and a longer duration of oxygen saturation <90% than during supine sleep, suggesting that cardiopulmonary responsiveness was impaired. Sleep efficiency, sleep stages, oxygen nadir, and carbon dioxide tension were not different during supine and prone sleep. Central apnea occurred more significantly than obstructive apnea. During supine and prone sleep, the CAI was 3.3 ± 2.9/h and 2.3 ± 2.6/h and the OAHI was 0.6 ± 0.7/h and 0.6 ± 0.8/h, respectively. We found one SNP rs3743340 in the NDN gene that had no effect on the sleep and respiratory parameters of PSG. CONCLUSION: Tachycardia and respiratory instability were recorded in neonates during prone sleep, suggesting that neonates are vulnerable to cardiopulmonary events during prone sleep. Therefore, young neonates should be kept in the supine sleep position unless there are contraindications.

[Effects of sleep body posture on subjective sleepiness in patients with OSAHS].

Objective:To observe the effects of sleep body posture on subjective sleepiness in patients with OSAHS.Method: We assessed the sleeping body position, the sleep structure, position specific AHI and the Epworth Sleepiness Scale (ESS) in a total of 90 patients with OSAHS. The patients were grouped according to AHI: mild OSAHS (5≤AHI<15), moderate (15≤AHI<30) and severe (AHI≥30). The polysomnography data and clinical characteristics were compared between each group.Result: There was statistically significant difference in arousal index，MinSpO2，REM% and NREM% among three groups (F value was 12.10,43.67,15.81,13.17，respectively，P<0.05). Compared with supine，the severe OSAHS group had significantly bigger changes in MinSpO2， REM% and NREM%（t value was 3.02,2.41,2.90，respectively，P<0.05）. For mild-to-moderate groups，there was no correlation between the ESS and the AHI at any position（P>0.05）. For severe group，the ESS was significantly correlated with L-AHI（r=0.454，P<0.01)；the REM L-AHI and NREM L-AHI was also significantly correlated with ESS of severe group (r=0.522 and 0.425，P<0.01). Conclusion:The sleep body posture had significant effects on sleep structure and respiratory events in severe OSAHS group. The L-AHI was found to have a closer association with daytime sleepiness in severe OSAHS than other groups.