Interventional study of comparing body pressure in different prone positions in healthy young women.

[Purpose] Although prone positioning is used to increase oxygenation in various respiratory conditions, this positioning can lead to facial and limb pressure ulcers. The aim in this study was to investigate body pressure variations in the prone position for different facial orientations and upper extremity positions. [Participants and Methods] Nineteen healthy young women participated in this study. Body pressure (maximum body pressure on the face, chest, elbows, and knees) was measured in six different prone positions with different face orientations and upper extremity positions, and the median value of each body pressure measurement was compared among postures. [Results] Face pressure tended to decrease when face orientation coincided with the raised side of the upper limb. In contrast, elbow pressure tended to be lower when the orientation of the face did not coincide with that of the raised side of the upper limb. [Conclusion] Pressure on the face and elbows can be reduced by placing the upper limbs in the prone position. This suggests that targeted and specific positioning may be useful for limiting the incidence and severity of pressure ulcers in these areas.

Determinants of Perceived Comfort: Multi-Dimensional Thinking in Smart Bedding Design.

Sleep quality is an important issue of public concern. This study, combined with sensor application, aims to explore the determinants of perceived comfort when using smart bedding to provide empirical evidence for improving sleep quality. This study was conducted in a standard sleep laboratory in Quanzhou, China, from March to April of 2023. Perceived comfort was evaluated using the Subjective Lying Comfort Evaluation on a seven-point rating scale, and body pressure distribution was measured using a pressure sensor. Correlation analysis was employed to analyze the relationship between perceived comfort and body pressure, and multiple linear regression was used to identify the factors of perceived comfort. The results showed that body pressure was partially correlated with perceived comfort, and sleep posture significantly influenced perceived comfort. In addition, height, weight, and body mass index are common factors that influence comfort. The findings highlight the importance of optimizing the angular range of boards based on their comfort performance to adjust sleeping posture and equalize pressure distribution. Future research should consider aspects related to the special needs of different populations (such as height and weight), as well as whether users are elderly and whether they have particular diseases. The design optimization of the bed board division and mattress softness, based on traditional smart bedding, can improve comfort and its effectiveness in reducing health risks and enhancing health status.

Comparative evaluation of the sleep quality metrics between a cardboard bed and a camp cot: a randomized controlled crossover study.

Background: Health-beneficial emergency bedding has become increasingly important for dealing with natural disasters such as the anticipated Nankai Trough earthquake in Japan. When the Great East Japan Earthquake occurred, cardboard beds were provided to evacuees. However, there were concerns about lower back pain and sleep disturbances, as cardboard beds offer insufficient pressure distribution. This study aimed to compare the effects of cardboard beds with those of foldable camp cots on sleep quality. Methods: A randomized controlled crossover study involving 20 healthy participants aged 18-45 years was conducted between June 2022 and January 2023. Participants were asked to sleep for one night on a camp cot and for another night on a cardboard bed, with a minimum three-day washout period between the two nights. Body pressure distribution and sleep metrics obtained from polysomnography (PSG) and questionnaires were compared between the two-bed types (P < 0.05). Results: The camp cot exhibited better body pressure distribution than a cardboard bed, leading to improved sleep satisfaction, bedding comfort, and reduced morning sleepiness. Nevertheless, polysomnography revealed no notable differences in sleep metrics or sleep architecture between the two types of beds. Conclusions: Our findings indicate that cardboard beds have lower pressure dispersion capabilities than camp cots, leading to an increased number of position changes during sleep. Additionally, subjective sleep quality, such as alertness on waking, sleep comfort, and sleep satisfaction, was lower for cardboard beds, suggesting that camp cots might offer a more comfortable bedding option for evacuees. However, there were no discernible differences between the two-bed types in terms of objective sleep metrics derived from PSG. The potential for sleep disturbances caused by lower back pain from a hard mattress has been noted, and it is possible that a single night's experience in healthy individuals might not be enough for sleep issues to manifest.

Static sitting posture control during writing tasks in idiopathic scoliosis among freshmen.

BACKGROUND: The posture control deficit is one important dysfunction in adolescent idiopathic scoliosis (AIS) patients, which is related to the development of the disease. However, it is not apparent whether AIS could affect static sitting posture control in late adolescence. OBJECTIVE: This study aims to compare static sitting posture control in idiopathic scoliosis freshmen with normal peers to reveal possible differences in posture stability between them during writing tasks. METHODS: In total, there were 10 AIS patients and 11 normal college students chosen for the writing task test. Data on the distribution of gluteal pressure during sitting were gathered. The comparison between these two groups was made using the independent sample t-test. RESULTS: The total excursion (TE) of the center of pressure (COP) of the AIS group considerably increased in comparison with the control group (CON) (p = 0.029). The AIS group's average COP velocity in the anteroposterior (AP) direction was significantly higher than the CON group (p = 0.048). The peak gluteal pressure on the right side was significantly higher in the AIS group than in the CON group (p = 0.039). The right gluteal contact area dynamic variation was significantly higher in the AIS group compared to the CON group (p = 0.025). CONCLUSIONS: AIS patients showed increased gluteal pressure and lower sitting posture stability during writing tasks.

Assessment of a Person's Emotional State Based on His or Her Posture Parameters.

This article is devoted to the study of the correlation between the emotional state of a person and the posture of his or her body in the sitting position. In order to carry out the study, we developed the first version of the hardware-software system based on a posturometric armchair, allowing the characteristics of the posture of a sitting person to be evaluated using strain gauges. Using this system, we revealed the correlation between sensor readings and human emotional states. We showed that certain readings of a sensor group are formed for a certain emotional state of a person. We also found that the groups of triggered sensors, their composition, their number, and their location are related to the states of a particular person, which led to the need to build personalized digital pose models for each person. The intellectual component of our hardware-software complex is based on the concept of co-evolutionary hybrid intelligence. The system can be used during medical diagnostic procedures and rehabilitation processes, as well as in controlling people whose professional activity is connected with increased psycho-emotional load and can cause cognitive disorders, fatigue, and professional burnout and can lead to the development of diseases.

Comparison of body pressure distribution in healthy subjects between bubble wrap and an emergency mattress laid on a cardboard bed: a randomized controlled crossover trial.

Background: It has been pointed out that the poor environment of evacuation shelters causes health problems and disaster-related deaths among evacuees, and we are concerned that their environment will deteriorate, particularly during a large-scale disaster due to a shortage of daily necessities. In Japan, evacuees usually slept on floors with futons until the Great East Japan Earthquake, but cardboard beds were installed in evacuation shelters. Previous studies have suggested that cardboard beds can reduce cold air transmission from the floor. We have reported that a cardboard bed can have a low-contact pressure dispersion capacity and cannot reduce musculoskeletal strain, unlike a futon or mattress. In the Great East Japan Earthquake, 33% of disaster-related deaths were reported to have been caused by physical or mental fatigue due to living in evacuation shelters. When a large-scale disaster such as the Nankai Trough Earthquake generates huge numbers of evacuees, the supply of mattresses for evacuees will be very difficult. Therefore, we considered potential alternatives that could be produced in large quantities over a short period. Bubble wrap, with very lightweight and waterproofing, could be a good candidate for mattress replacement. This study aimed to investigate the improvement in body pressure distribution and pressure-sensing area when using bubble wrap. Methods: Twenty-seven healthy subjects allocated to sequences A and B with different intervention order were laid in supine and lateral positions on a cardboard bed without a mattress, bubble wrap, or air mattress: the mattress-body contact pressure and contour areas were measured, and subjective firmness and comfort during these conditions were also investigated using the visual analog scale (VAS). Acquired data were analyzed using a linear mixed-effects model and Bonferroni's post-hoc test, and P < 0.05 was considered statistically significant. Results: The mattress-body contact pressure and contour area showed significant differences with and without air mattresses. With the air mattresses, the pressure in the supine position decreased by 34%, and that in the lateral position decreased by 13%. However, the four-fold bubble wrap did not improve the mattress-body contact pressure and contour area; the change ratios were within 5% compared to the cardboard bed. However, there were significant differences in subjective firmness and comfort using the VAS among all experimental positions. Conclusion: Our study showed that bubble wrap could not significantly improve body pressure concentration and may not be a satisfactory substitute for air mattresses. Because of the improvement in subjective firmness and comfort with the bubble wrap, using it for an extended period may affect the incidence of back pain in evacuees. Finally, we hypothesize that the body pressure dispersion of the bubble wrap may be improved by changing the air-filling rate and the size of the air bubbles.

Effect of changing the lying posture angle by changing the bed posture on the average pressure, maximum pressure, and pressure area in the hip region.

BACKGROUND: An electric bed can easily change posture from a lying position and was effective in preventing pressure ulcer. OBJECTIVE: This study aimed to identify the optimal posture for the prevention of pressure ulcers by analyzing pressure changes applied to the pelvic region. METHODS: Pressure changes resulting from lateral rotations of the body using an electronic adjustable bed and changes in the posture and angles of the trunk and knees were assessed. Twelve conditions with varying angles of the trunk and knees (15-35∘ in 5∘ increments) and varying lateral angles (20-35∘ in 5∘ increments) were tested. The pressure (maximum and average) and contact area in the pelvic region of 20 individuals without disabilities were calculated. RESULTS: The conditions in which the average and maximum pressures did not increase according to the increase in angle were 25∘ for the upper body and knee angles and 35∘ for the side. CONCLUSIONS: The body pressure changed according to the posture rather than according to physical characteristics. Lateral rotation combined with changes in the angles of the trunk and knees effectively prevented pressure ulcers. Changes in the posture at various angles prevented an increased pressure on the body.

Cardboard Bed Without Mattress Is Ineffective in Improving the body Contact Pressure-a Preliminary Study Using a Dummy Model.

OBJECTIVE: This study aimed to describe and evaluate the dispersion of body-mattress contact pressure on a cardboard bed and investigate whether the cardboard bed has a positive effect on evacuees' musculoskeletal burden. MATERIALS AND METHODS: A high-performance nursing simulator was used to measure the contact pressure and the body surface contour area of the bed, and these values were collected with the patient in the supine position using the Body Pressure Measurement System. Data of each test were acquired 10 times and were compared among 4 conditions (plastic sheet, cardboard bed, cardboard bed with a blanket, and cardboard bed with a mattress-topper). The data analysis for body-mattress contacts pressure and the surface contour area of the whole body, head, chest, and buttocks were conducted by one-way repeated analysis of variance and Bonferroni post-hoc test. RESULTS: The average body-contact pressure on the cardboard bed did not decrease compared with that on the floor with plastic sheets. In contrast, the body surface contour area was significantly different among any other conditions, but the gap was only approximately 16%. However, the body-contact pressure and the body surface contour area were improved when a mattress-topper was added on the cardboard bed. When a blanket was laid on the cardboard bed, the contact area was increased. CONCLUSION: Our results indicate that the pressure dispersion ability of the cardboard bed was not sufficient; however, adding the mattress-topper or the blanket could contribute to an improvement in the evacuees' musculoskeletal burden. Many evacuees lay a mattress topper or futon on a cardboard bed after installing cardboard beds. Our findings may also support the scientific validity of the evacuees' actual sleeping style in Japan. This preliminary study provides the basis for future research on exploring an appropriate sleeping bed condition in evacuee shelters.

The Ideal Body: A Social Construct? Reflections on Body Pressure and Body Ideal Among Students in Upper Secondary School.

Several studies show that young people today are negatively impacted by body image ideals in social media. We studies young people's reflections on body image and body pressure. More precisely: How does a selected group of third-year upper secondary school students understand their body images and body pressures through social media? Eight third-year students, four of each gender, were interviewed from two upper secondary schools in a medium-sized city in Norway. An interesting find was that body pressure was not experienced solely as one-sided pressure exerted externally by media sources, but that they also personally influenced others through their own active use of social media channels like Facebook and Instagram. They reported having experienced body pressure in their own lives and in their immediate environment, and that both genders are affected. The study builds on sociocultural body theory based on Foucault's ideas and work, but also uses more recent media theory for the analysis and discussion. A BOPS model developed by the researchers was used for the operational parameters that is centered around the concepts of panopticon, synopticon and omniopticon.

Pillow Support Model with Partitioned Matching Based on Body Pressure Distribution Matrix.

(1) Objective: Sleep problems have become one of the current serious public health issues. The purpose of this research was to construct an ideal pressure distribution model for head and neck support through research on the partitioned support surface of a pillow in order to guide the development of ergonomic pillows. (2) Methods: Seven typical memory foam pillows were selected as samples, and six subjects were recruited to carry out a body pressure distribution experiment. The average value of the first 10% of the samples in the comfort evaluation was calculated to obtain the relative ideal body pressure distribution matrix. Fuzzy clustering was performed on the ideal matrix to obtain the support surface partition. The ideal body pressure index of each partition was calculated, and a hierarchical analysis of each partition was then performed to determine the pressure sensitivity weight of each partition. Using these approaches, the key ergonomic node coordinates of the partitions of four different groups of people were extracted. The ergonomic node coordinates and the physical characteristics of the material were used to design a pillow prototype. Five subjects were recruited for each of the four groups to repeat the body pressure distribution experiment to evaluate the pillow prototype. (3) Results: An ideal support model with seven partitions, including three partitions in the supine position and four partitions in the lateral position, was constructed. The ideal body pressure distribution matrix and ideal body pressure indicators and pressure sensitivity weights for each partition were provided. The pillow that was designed and manufactured based on this model reproduced the ideal pressure distribution matrix evaluated by various groups of people. (4) Conclusion: The seven-partition ideal support model can effectively describe the head and neck support requirements of supine and lateral positions, which can provide strong support for the development of related products.

Model construction and analysis of ride comfort for high-speed railway seat cushions.

BACKGROUND: More and more people choose to travel by high-speed railway. The seats in these vehicles are an important contact point and comfort of the seat cushions needs attention. OBJECTIVE: The aim of this study is to choose among three seat cushions, the one that creates most comfort for a high-speed train. METHODS: Twelve healthy volunteers were selected to participate in the experiment. Three different surface shape models of high-speed railway seat cushions were used. The Seat Pressure Distribution Index (SPD%) was calculated and analysed. A 7-point Likert scale questionnaire was applied for subjective evaluation. RESULTS AND CONCLUSION: The evaluation is based on subjective and objective data. The results showed that the front protruding cushion made the pressure distribution more even, while the flat cushion had the smallest SPD% and the static pressure was most evenly distributed. This knowledge was beneficial for the design of comfortable high-speed railway seat cushions.

Active Body Pressure Relief System with Time-of-Flight Optical Pressure Sensors for Pressure Ulcer Prevention.

A body pressure relief system was newly developed with optical pressure sensors for pressure ulcer prevention. Unlike a conventional alternating pressure air mattress (APAM), this system automatically regulates air flow into a body supporting mattress with adaptive inflation (or deflation) duration in response to the pressure level in order to reduce skin stress due to prolonged high pressures. The system continuously quantifies the body pressure distribution using time-of-flight (ToF) optical sensors. The proposed pressure sensor, a ToF optical sensor in the air-filled cell, measures changes in surface height of mattress when pressed under body weight, thereby indirectly indicating the interface pressure. Non-contact measurement of optical sensor usually improves the durability and repeatability of the system. The pressure sensor was successfully identified the 4 different-predefined postures, and quantitatively measured the body pressure distribution of them. Duty cycle of switches in solenoid valves was adjusted to 0-50% for pressure relief, which shows that the interface pressure was lower than 32 mmHg for pressure ulcer prevention.

Sleeping mattress determinants and evaluation: a biomechanical review and critique.

BACKGROUND: Sleeping mattress parameters significantly influence sleeping comfort and health, as reflected by the extensive investigations of sleeping support biomechanics to prevent sleep-related musculoskeletal problems. METHODOLOGY: Herein, we review the current trends, research methodologies, and determinants of mattress biomechanics research, summarizing evidence published since 2008. In particular, we scrutinize 18 articles dealing with the development of new designs, recommendation criteria, instruments/methods of spine alignment evaluation, and comparative evaluation of different designs. RESULTS: The review demonstrated that mattress designs have strived for customization, regional features, and real-time active control to adapt to the biomechanical features of different body builds and postures. However, the suggested threshold or target values for desirable spine alignment and body pressure distribution during sleep cannot yet be justified in view of the lack of sufficient evidence. CONCLUSIONS: It is necessary to formulate standard objectives and protocols for carrying out mattress evaluation.

Revisiting human cerebral blood flow responses to augmented blood pressure oscillations.

KEY POINTS: Cerebral autoregulation is most effective in buffering against pressure fluctuations slower than 0.03 Hz (∼30 s). This suggests that frequency bands for characterizing cerebral autoregulation should be redefined Low cross-spectral coherence below 0.03 Hz highlights the limitations of transfer function approaches Haemodynamic changes induced by lower body pressure could not fully explain the differences in autoregulation estimated from spontaneous vs. augmented fluctuations, and thus, observations of spontaneous fluctuations should not be relied on whenever possible. ABSTRACT: There is currently little empirical basis for time scales that are considered to be most significant in cerebrovascular counter-regulation of changes in arterial pressure. Although it is well established that cerebral autoregulation behaves as a 'high-pass' filter, recommended frequency bands have been largely arbitrarily determined. To test effectiveness of cerebral autoregulation, we refined oscillatory lower body pressure (LBP) to augment resting pressure fluctuations below 0.1 Hz by a factor of two in 13 young male volunteers, and thoroughly characterized the time and frequency responses of cerebral autoregulation. We observed that despite a threefold increase in arterial pressure power <0.03 Hz with oscillatory LBP, there was no change in cerebral blood flow power, indicating near perfect counter-regulation. By contrast, in the range 0.03-0.10 Hz, both cerebral blood flow and arterial pressure power more than doubled. Our data demonstrate that cerebral autoregulation is most effective in buffering against pressure fluctuations slower than 0.03 Hz (∼30 s). This suggests that frequency bands of interest should be redefined and recording length should be increased considerably to account for this. Furthermore, low cross-spectral coherence below 0.03 Hz, even when pressure fluctuations were augmented, highlights the uncertainty in transfer function approaches and the need to either report precision or use non-linear approaches. Finally, haemodynamic changes induced by LBP could not fully explain the differences in autoregulation estimated from spontaneous vs. augmented fluctuations, and thus, observations of spontaneous fluctuations should not be relied on whenever possible.

Analysis of body pressure distribution on car seats by using deep learning.

This study aimed to extract information from body pressure distribution, including comfort, participant body size, and seat characteristics by using supervised deep learning, and body pressure characteristics corresponding to sensory evaluation by using unsupervised deep learning. Body pressure data of 18 participants and 19 kinds of car seats were used for the analysis. Sensory evaluation of 9 items concerning cushion characteristics and seat comfort was conducted. From the analysis, we determined that body size and car seats could be classified with high precision by using body pressure distribution data. For the sensory evaluation items, the correct answer rate was high. By examining the importance of the cells of the mat, the features of the body pressure mat at the seat cushion and backrest, body size, car seat, and parts related to sensory evaluation could be determined in detail. The study findings can be applied in the development of car seats.

Relative contributions of systemic hemodynamic variables to cerebral autoregulation during orthostatic stress.

Postural changes impair the ability of the cerebrovasculature to buffer against dynamic pressure fluctuations, but the mechanisms underlying this impairment have not been elucidated. We hypothesized that autoregulatory impairment may reflect the impact of static central volume shifts on hemodynamic factors other than arterial pressure (AP). In 14 young volunteers, we assessed the relation of fluctuations in cerebral blood flow (CBF) to those in AP, cardiac output, and CO2, during oscillatory lower body pressure (LBP) (±20 mmHg at 0.01 and 0.06 Hz) at three static levels (-20, 0, and +20 mmHg). Static and dynamic changes in AP, cardiac output, and CO2 explained over 70% of the variation in CBF fluctuations. However, their contributions were different across frequencies and levels: dynamic AP changes explained a substantial proportion of the variation in faster CBF fluctuations (partial R2 = 0.75, standardized ß = 0.83, P < 0.01), whereas those in CO2 explained the largest portion of the variation in slow fluctuations (partial R2 = 0.43, ß = 0.51, P < 0.01). There was, however, a major contribution of slow dynamic AP changes during negative (ß = 0.43) but not neutral (ß = 0.05) or positive (ß = -0.07) LBP. This highlights the differences in contributions of systemic variables to dynamic and static autoregulation and has important implications for understanding orthostatic intolerance. NEW & NOTEWORTHY While fluctuations in blood pressure drive faster fluctuations in cerebral blood flow, overall level of CO2 and the magnitude of its fluctuations, along with cardiac output, determine the magnitude of slow ones. The effect of slow blood pressure fluctuations on cerebrovascular responses becomes apparent only during pronounced central volume shifts (such as when standing). This underlines distinct but interacting contributions of static and dynamic changes in systemic hemodynamic variables to the cerebrovascular regulation.

Finite element modeling for predicting the contact pressure between a foam mattress and the human body in a supine position.

In this paper, we generated finite element (FE) models to predict the contact pressure between a foam mattress and the human body in a supine position. Twenty-year-old males were used for three-dimensional scanning to produce the FE human models, which was composed of skin and muscle tissue. A linear elastic isotropic material model was used for the skin, and the Mooney-Rivlin model was used for the muscle tissue because it can effectively represent the nonlinear behavior of muscle. The contact pressure between the human model and the mattress was predicted by numerical simulation. The human models were validated by comparing the body pressure distribution obtained from the same human subject when he was lying on two different mattress types. The experimental results showed that the slope of the lower part of the mattress caused a decrease in the contact pressure at the heels, and the effect of bone structure was most pronounced in the scapula. After inserting a simple structure to function as the scapula, the contact pressure predicted by the FE human models was consistent with the experimental body pressure distribution for all body parts. These results suggest that the models proposed in this paper will be useful to researchers and designers of products related to the prevention of pressure ulcers.

Differences in the body pressure-related sensory changes between the floor and mattress in a static supine position for physiotherapy research: a randomized controlled pilot trial.

[Purpose] This study was performed to investigate the difference in body pressure-related sensory changes between the floor and mattress in a static supine position for physiotherapy research. [Subjects and Methods] To analyze body pressure, the Body Pressure Measurement System was used. Body pressure sensors were attached to mattresses and the floor beneath the subjects. The level of pain was evaluated using pain score tools before the static supine position was adopted, at 1, 5, 10, and 15 min, and in total for specific body points. [Results] In analysis of digitized images, there was no significant difference observed between floor and mattress body pressure values at the start position. However, the head pressure intensity was significantly higher than that of the other body parts. In analysis of pain scores, all body part pain scores except those for both legs were significantly higher for the floor than for the mattress. Furthermore, the pain scores of the floor group were significantly increased at minute 1 compared with those of the mattress group. [Conclusion] These results suggest that properties that change in a time-dependent manner and postural changes need to be carefully considered when applying physical therapy.