Multi-link operation is a new feature of IEEE 802.11be Extremely High Throughput (EHT) that enables the utilization of multiple links using individual frequency channels to transmit and receive between EHT devices. This paper aims to illustrate enhanced multi-link channel access schemes, identify the associated coexistence challenge, and propose solutions. First, we describe the multi-link operation of IEEE 802.11be and how the asynchronous and synchronous channel access schemes facilitate multi-link utilization. Next, we describe the design variants of the synchronous channel access scheme and demonstrate the associated coexistence challenge. Subsequently, we propose four features to address this challenge by assigning penalties to multi-link devices  as well as five coexistence solutions derived from combinations of these features. Comparative simulation results are provided and analyzed for dense single-spot and indoor random deployment scenarios, demonstrating that the throughput and latency gains of multi-link operation differ between schemes. At the same time, we investigate the coexistence performance of multi-link operation with and without the capability of simultaneous transmission and reception and demonstrate that the proposed solutions mitigate the coexistence problem. In particular, compensating the backoff count achieves the highest coexistence performance among the proposed solutions, with a marginal throughput decrease of multi-link devices. A metric for evaluating both the throughput and latency gains and the coexistence performance of a multi-link channel access scheme using a single value is also proposed. Extremely High Throughput (EHT), is under development by the 802.11be task group of IEEE (TGbe) [Mobile data traffic is expected to grow at a compound annual growth rate (CAGR) of 46% by 2022 . One of E (TGbe) ,4, and iE (TGbe) ,6,7,8,9.multi-link operation. While physical-layer enhancements, including new bands, wider bandwidths, and higher spatial and modulation orders, are also to be adopted, as was done for prior generations, multi-link operation is a new approach being attempted for the first time in EHT. The idea is to enable a pair of devices to use multiple wireless links in different bands simultaneously for transmission and reception. The main benefit of this approach is the simultaneous exploitation of multiple bands at a lower hardware cost than that of a single multiband radio. This multi-link operation capability is different from the multiband support offered by the access points (APs) currently available on the market in that multi-link operation allows the concurrent use of multiple links at client devices and thus also enhances the throughput of a single data session .A new feature of the medium access control (MAC) layer for the realization of EHT is The main challenges of multi-link operation are (1) the design of channel access schemes with and without the presence of radio frequency (RF) power leakage between links, and (2) the coexistence of devices using multi-link channel access schemes with legacy devices. A straightforward approach to channel access in multi-link operation is to run individual links with independent channel access processes, as in the conventional case; however, this is only possible when no RF power leakage exists between the links. If RF power leakage is present between the links due to imperfect RF shielding, filter artifacts, etc., then synchronous channel access is preferred. Moreover, multi-link devices using these channel access schemes must coexist well with legacy devices when occupying the shared medium.There have been some research attempts toward multi-link aggregation in the unlicensed spectrum. Glia  is a sofThis paper aims to illustrate enhanced multi-link channel access schemes for IEEE 802.11be EHT, identify the associated coexistence challenge, and propose solutions applicable to cases both with and without the capability of simultaneous transmission and reception. First, we describe the concept, architecture, and asynchronous and synchronous channel access schemes of multi-link operation, along with the RF power leakage problem. Next, we describe the design variants of the synchronous channel access scheme and demonstrate the coexistence challenge of the enhanced scheme. Subsequently, we propose four features to mitigate this challenge by assigning penalties to multi-link devices: repicking a backoff count, doubling the contention window size, switching to another contention window set, and compensating the backoff count. Then, five coexistence solutions are derived from combinations of these features. Comparative evaluation results are provided and analyzed for dense single-spot and indoor random deployment scenarios, demonstrating that the throughput and latency gains of multi-link operation differ between schemes. We also investigate the coexistence performance of multi-link operation with and without the capability of simultaneous transmission and reception and demonstrate that the proposed solutions mitigate the coexistence problem to different degrees. In particular, compensating the backoff count achieves the highest coexistence performance among the proposed solutions, with a marginal throughput decrease of multi-link devices. A metric for evaluating both the throughput and latency gains and the coexistence performance of a multi-link channel access scheme using a single value is also proposed.Identification of the issue concerning the coexistence of an enhanced synchronous multi-link channel access scheme with legacy devices, which has not been explored yet in the literature.Design of features to assign a penalty to a backoff process and coexistence solutions derived from various feature combinations.Comprehensive simulation to illustrate the throughput and latency gains and coexistence performance of various multi-link channel access schemes including the proposed solutions when multi-link devices coexist with legacy devices.Design of a new metric for evaluating both the throughput and latency gains and the coexistence performance of multi-link operation using a single value.In summary, the main contributions of our work are listed as follows:The rest of this paper is organized as follows. Multi-link operation (MLO) is the concurrent utilization of multiple radio links of different frequency channels/bands by an AP, a client, or both. It is a MAC-layer solution for concurrently using multiple links and thus exposes a single MAC service access point (SAP) to the upper sublayer of the data link layer, i.e., the logical link control (LLC) layer. Therefore, existing user services and higher-layer protocols need not expend any effort to enjoy its benefits.n links can achieve identical throughput, their MLO should ideally achieve The motivation for MLO is to increase throughput by aggregating multiple bandwidths across bands at a low hardware cost. Ideally, the maximum achievable throughput of MLO is the sum of the achievable throughput for each link. For example, if each of This throughput increase enabled by MLO comes from the use of a wider bandwidth through the aggregation of multiple links. MLO has several advantages over conventional single-link operation (SLO) using a wide bandwidth. First, it allows the aggregation of available bandwidths across bands, such as 2.4, 5, 6 and even 60 GHz, at an affordable hardware cost by reusing most of the existing physical (PHY)-layer and lower-MAC (LMAC) functionalities while reinventing the upper-MAC (UMAC) component only. Second, it has the opportunity to run multiple channel access processes in individual links thanks to multiple RF chains. This is beneficial in exploiting each link’s bandwidth in a manner that is more adaptive to its conditions, such as contention intensity. In contrast, the conventional wideband operation of IEEE 802.11 runs a single channel access process in a primary channel only, and thus significantly depends on the conditions of this single channel; for example, if the primary channel is crowded, fewer transmission opportunities are available for wideband operation regardless of the conditions of the other channels.multi-link device (MLD), while a legacy device supporting SLO only is called a single-link device (SLD). Each link of an MLD is regarded as a conventional single-link station (STA), and an MLD is considered to be a device affiliated with more than one STA. In contrast, an SLD (legacy device) is affiliated with only a single STA. Thus, we use the terms “legacy device” and “legacy STA” interchangeably. MLDs can be further classified into two types based on the type of the affiliated STAs:AP multi-link device (AP MLD): each of the affiliated STAs is an AP.Non-AP multi-link device (non-AP MLD): each of the affiliated STAs is a non-AP (client) STA.The system architecture for MLO is illustrated in Each affiliated STA of an MLD is composed of PHY and LMAC components. On top of the set of affiliated STAs, an MLD has one UMAC component to aggregate its set of affiliated STAs and provide LLC with a single MAC SAP. An AP STA and any non-AP STAs associated with it form a basic service set (BSS). As illustrated in IEEE 802.11 defines a traffic identifier (TID) to classify a packet for differentiated service. The TID is represented as a four-bit number (0–7) identifying the desired quality of service (QoS) for the traffic. In MLO, the TID is used to determine which link(s) to use for traffic with a specific QoS. If a specific TID is mapped to a set of links, then any link within that set can be used to transmit data frames from that TID. By default, after multi-link setup, all TIDs are mapped to all established links. However, the TID-to-link mapping can specify either the same or different link sets for each TID. After multi-link setup, the TID-to-link mapping can be updated through negotiation.In this mapping strategy, each TID is mapped to a single link, meaning that traffic with a given TID will be transmitted using the associated dedicated link only. Distributing individual traffic flows defined by different TIDs to different links in this way will lead to increased throughput and decreased latency. However, since TID-to-link mapping updates may not be frequent, the effect of the throughput increase achieved with this strategy is somewhat limited; even if the amount of traffic associated with a particular TID is large and the corresponding link queue becomes congested, other links cannot be used for this TID. For the same reason, however, this mapping strategy is beneficial for high-priority TIDs because it physically isolates the associated link resources from other lower-priority TIDs.To fully exploit the throughput increase and latency decrease effects of MLO, a TID can be mapped to a set of multiple links, allowing traffic with that TID to be transmitted using any link in this set, as illustrated in However, such a strategy is inherently accompanied by the reordering of packets; thus, the UMAC on the receiver side must buffer the received traffic and pass packets in sequence only to the LLC layer. Therefore, received packets may wait in the receiver buffer until they can be arranged in sequence. To achieve this, multiple links for same-TID packets must use a common sequence number space shared across multiple links.For multi-link channel access, multiple operation options are considered. The usability of these options is related to the simultaneous transmission and reception (STR) capability of a device. In what follows, we first explain the STR capability, describe two basic multi-link channel access schemes, and present variants for enhancement along with the coexistence issue.Since multiple radio interfaces exist within a single MLD, near-band in-device interference may arise. STR MLD: A transmission on one link does not affect the operations of frame reception and CCA on other links. Therefore, individual links can operate independently of each other.Non-STR MLD: Operation on one link is restricted by operation on another link; a transmission on one link is not allowed if it will cause reception interruption on another link, or a reception or CCA on one link is not allowed if a transmission is ongoing on another link.If an MLD is equipped with high-fidelity filters and shielding, this RF power leakage problem can be avoided, thus enabling STR. However, if the level of power leakage to the nontransmitting links of an MLD ruins either their clear channel assessment (CCA), signal reception, or both (We consider the case in which the power leakage of a transmitting link ruins both the CCA and reception of other links in an MLD), it does not have the STR capability. Depending on whether they possess the STR capability, MLDs can be classified into the following two types:In general, an AP MLD should be capable of STR, while different non-AP MLDs may have different STR capabilities. Therefore, IEEE 802.11be WLANs support the following cases: STR AP MLDs with STR non-AP MLDs and non-STR non-AP MLDs. It is still important to provide non-STR MLDs with throughput enhancement and latency reduction close to those of STR MLDs.Asynchronous Operation (Async). The MLO functionality of EHT allows an asynchronous multi-link channel access scheme in which each of the STAs belonging to an MLD performs a channel access process  over its own link independently. Therefore, as illustrated in This Async scheme is ideal for STR MLDs. However, if it is applied to a non-STR MLD, as shown in Synchronous Operation (Sync). The synchronous multi-link channel access scheme of EHT is illustrated in The Sync scheme is specifically designed for non-STR MLDs but is also applicable to STR MLDs. Because it only allows simultaneous transmission initiation on all links, it is unaffected by RF power leakage between links and thus operates similarly in STR and non-STR MLDs. However, it may not utilize multiple channels as optimally as Async since all links must have backoff counts of zero when their individual channels are idle.Sync-PL: This scheme resembles the conventional wideband operation of IEEE 802.11 [E 802.11 ,18, as iSync-FT: This scheme is a hybrid of the Sync and Async schemes for faster transmission (FT) when a multi-link transmission opportunity is available, as illustrated in This operation scheme lessens the failure of link utilization in non-STR MLDs due to RF power leakage, thus enhancing their multi-link utilization. As illustrated in We consider two design variants of the Sync scheme for better exploitation of multi-link transmission opportunities:free-riding link in this paper. A free-riding link resumes its ongoing BO after transmission is complete, using the count value frozen immediately before the transmission. This behavior prioritizes channel access for the MLD and provides it with more TXOPs, resulting in long and frequent wait times for the legacy device. This behavior can also be interpreted as the free-riding link starting a new BO with a relatively deflated backoff count.In practical WLANs, legacy SLDs may coexist with EHT MLDs. Therefore, a coexistence issue arises between them. An illustration of such a coexistence scenario is given in In what follows, we describe the details of the proposed solutions. The approach of the proposed solutions is to assign a free-riding link a penalty for its subsequent channel access following a free-ride transmission so that each link of an MLD will experience a similar amount of backoff time as a legacy device does in the same channel. We propose four features for assigning penalties to free-riding links. Then, various combinations of these features are considered as solutions, as listed in Repick. Since the link may have performed a BO before the free-ride transmission and reduced the backoff count by some amount, allowing it to repick a new backoff count will increase its backoff time on average. In the example shown in the figure, the free-riding link (Link 2) with Repick starts a new BO with a backoff count of nine. Without this feature, the link would use the previous count of three (STR case) or one (non-STR case). The newly repicked count value is not affected by whether the free-riding transmission was successful. It follows the current CW value of the link.This feature allows a free-riding link to repick a new backoff count and restart a BO based on this new count immediately after a free-ride transmission ; thus, wDouble and Double + Repick, respectively. Double allows an STA to continue its BO with its remaining backoff count, as illustrated in The next feature uses CW doubling as a penalty. Upon completion of a free-riding transmission, the CW of the corresponding link is doubled; consequently, the next backoff count to be picked for this link will have a higher value on average. We propose two solutions that use this feature, which we call Switch. After a link is given a channel access opportunity by free riding, we switch the link to CW set B so that it has to wait longer on average for channel access due to its own BO completion. A timer (This feature is inspired by the multi-user mode of enhanced distributed channel access (MU-EDCA) in 802.11ax , which pb. Then, it performs a new BO with an initial count of Algorithm 1 Proposed multi-link channel access procedure of an STA.1:while the STA has a packet to transmit do2: 3:whiledo   4:if Other STA has completed a backoff process and is about to transmit a packet then  5:if the channel is idle for PIFS then   6:    Transmit the packet in the given channel  7:if the MLD uses the Switch Scheme then    8:     9:     Start a timer with an expiration time of 10:end if     11:if the MLD uses the Doubling Scheme then    12:     13:end if     14:if the MLD uses the Repick Scheme then    15:     16:end if     17:if the MLD uses the Compensation Scheme then    18:     19:end if     20:end if    21:end if   22:while the channel is sensed busy do  23:   Sense the channel for DIFS  24:end while   25:  26:end while  27: Transmit the packet in the given channel  28:if the MLD uses the Switch Scheme then 29:  30:end if  31:if the transmission succeeds then 32:  33:else 34:  35:end if  36:end while The last feature compensates the backoff count of a free-riding link by a certain amount such that it will ultimately go through the full backoff time length on average. The operation of the solution that utilizes this feature is illustrated in Single-spot deployment: All APs and devices are deployed at a single spot. APs/devices of the same type have the same modulation and coding scheme (MCS). This deployment scenario enables us to clearly observe and analyze the coexistence performance.Indoor random deployment: Following the 3rd Generation Partnership Project (3GPP)’s indoor evaluation scenario for coexistence in unlicensed spectrum [spectrum , the APsWe evaluate and compare the performance gain and coexistence performance of MLO under various channel access schemes through simulation (We used a Matlab-based in-house simulator). In addition to the two basic channel access schemes of EHT MLO, i.e., Async and Sync, we also evaluate Sync-PL and Sync-FT as well as the coexistence solutions for Sync-FT described in the previous section. In this evaluation, we consider two deployment scenarios:(Phase 1) Legacy devices only: Only legacy devices exist in the simulated environment.(Phase 2) MLD vs. legacy devices: Half of the legacy devices from the first phase are replaced with MLDs.The coexistence performance of MLO is investigated by comparing the throughput and latency performance of legacy devices between the cases without and with MLDs. To this end, two phases of simulation are performed, as illustrated in In the transition from Phase 1 to 2, one legacy device is replaced with one MLD. The purpose is to evaluate the coexistence performance of MLO when the number of coexisting devices remains unchanged. Phase 1 reflects the baseline performance of the conventional single-link channel access scheme. Phase 2 reveals, compared with the performance in Phase 1, how much of a performance gain MLO achieves and how much of a performance degradation the legacy devices suffer. As the performance of the legacy devices in Phase 2 decreases relative to that in Phase 1, the MLDs coexist more poorly with the legacy devices.The simulation parameters are listed in In this deployment scenario, we first investigate the throughput gain of MLO. Then, we present the coexistence performance and evaluate it using a new metric.First, we consider one MLD deployed with various numbers of overlapping BSSs (OBSSs) with legacy SLDs. The MLD is contending on both link 1 and link 2. OBSSs are added to each of the links at the same time, i.e., one OBSS means one legacy BSS on link 1 and link 2. The performance gain of MLO is evaluated in terms of throughput enhancement.The throughput performance results of MLO using different channel access schemes with coexisting legacy devices are presented in Next, we investigate the coexistence performance of MLO. The throughput results for the coexistence evaluation scenario in In the case with the STR capability, as shown in To evaluate both the throughput and latency gains and the coexistence performance between different schemes using a single metric, we introduce a new metric The new metrics, denoted by The new metric of throughput performance, i.e., In this simulation, the deployment scenario follows the 3GPP’s indoor coexistence evaluation scenario , as showIn this paper, we illustrated the MLO functionality of the upcoming IEEE 802.11be standard and described how the channel access schemes of IEEE 802.11be facilitates multi-link utilization. We demonstrated the coexistence challenge presented by the enhanced synchronous channel access scheme, and we proposed solutions to mitigate this challenge. Through comprehensive simulations, we evaluated the throughput and latency gains of MLO and the proposed solutions relative to legacy systems in various network environments. At the same time, we investigated the coexistence performance of MLO with and without the STR capability and demonstrated that the proposed solutions mitigate the coexistence problem of the enhanced synchronous channel access scheme to different degrees. A metric for evaluating both the throughput and latency gains and the coexistence performance of a multi-link channel access scheme using a single value was also proposed. The evaluation results showed that, among the proposed solutions, compensating the backoff count achieves the best coexistence performance with a marginal throughput decrease of MLDs. However, there may arise a backoff count overflow problem that the backoff count of an MLD accumulated by repeated compensations gets excessive, thus not giving a transmission opportunity to the MLD once an overflow occurs. We leave an extended design of the compensation feature to handle this problem as future work. As machine learning has been applied to a wide range of communication and networking problems , develop


Disease-related malnutrition is associated with adverse outcomes such as increased rates of morbidity and mortality, prolonged hospital stay, and extra costs of health care. This study was conducted to assess nutritional status among patients and to determine the risk factors for malnutrition in Iran university f.Persian Nutritional Survey In Hospitals (PNSI) was a cross-sectional study that conducted in 20 university hospitals across Iran. All the patients with age range of 18 to 65 years, who were admitted or discharged, were assessed by subjective global assessment (SGA).2, respectively. Malnutrition (SGA-B & C) was identified in 23.92% of the patients, 26.23 and 21% of whom were among the admitted and discharged patients, respectively. The highest prevalence of malnutrition was in burns (77.70%) and heart surgery (57.84%) patients. Multivariate analysis presented male gender , malignant disease , length of hospital stay , and polypharmacy  as independent risk factors for malnutrition. Malnutrition was not associated with age (P = 0.10).In total, 2109 patients were evaluated for malnutrition. Mean values of age and body mass index were 44.68 ± 14.65 years and 25.44 ± 6.25 kg/mThis study provides an overall and comprehensive illustration of hospital malnutrition in Iran university hospitals, finding that one out of four patients were malnourished; thus, appropriate consideration and measures should be taken to this issue.The online version contains supplementary material available at 10.1186/s12937-021-00741-1. Disease-related malnutrition is associated with adverse outcomes such as increased rates of morbidity and mortality, prolonged hospital stay, impaired wound healing, high readmission rate, and increased costs for health care –4.Malnutrition development is associated with insufficient dietary intake or malabsorption, increased nutritional needs, complications of the underlying disease, or a combination of these factors . There iStudies performed in the United States indicate that approximately 32.7% of hospital patients are either malnourished or at nutritional risk , they al2 [There are different reports of malnutrition prevalence in Iran, Hosseini reported 5.7% of patients on admission and 11% of discharged patients had malnutrition based on body mass index (BMI) ≤18.5 kg/m2 . Forty-t2 . Another2 . A recen2 .Proper nutritional status can play a notably important role in lowering the incidence of the malnutrition-disease defective cycle. Despite the importance of disease-related malnutrition and the great economic costs of this condition imposes on health systems, there is no comprehensive data on disease-related malnutrition and related risk factors in Iran hospitals. Therefore, this study aimed to assess nutritional status among patients in Iran hospitals and to determine different risk factors for malnutrition in hospitalized patients.P = 0.32, Z = 95%, d = 0.02) [Persian Nutritional Survey In Hospitals (PNSI) is a multicenter, cross-sectional study conducted in 20 public hospitals which were selected based on a random stratified-cluster method. The sample size was estimated as 2100 patients, based on the relevant formula , and dat = 0.02) . InformeIn each hospital, the investigators referred to included clinical wards and assessed newly admitted or discharged patients on a specified date consecutively. The inclusion criteria comprised of admitted or discharged patients within the age of 18 to 65 years with Iranian nationality, also we excluded duplicated patients. Patients undergoing surgery on the data collection day, outpatients, patients with trauma or eating disorders, and patients admitted to maternity, obstetric, pediatric, orthopedic, and emergency departments or intensive care units (ICUs) were excluded from the study. The study was conducted from 24th to 28th November 2015. STROBE checklist of study is available as supplementary material Patient characteristics, i.e., gender, date of birth (age), underlying disease, the main affected organ, comorbidity, the number of different prescriptions per day, and history of ICU stay and surgery were recorded. The length of hospital stay was calculated for discharged patients from the date of admission and date of the survey. Body weight was measured by standard Seca scale  in light clothes to the nearest 1 kg. Body height was assessed by Seca portable stadiometer  to the nearest 1 cm. Mid-arm circumference (MAC) was measured in mid-acromion and olecranon process interval at the non-dominant relaxed arm with a non-stretchable tape measure to the nearest 0.1 cm.The nutritional status of patients was assessed by subjective global assessment (SGA) and anthropometric measures (BMI and MAC) for all the admitted and discharged patients included in the study .SGA is a valid and reliable tool for assessing nutritional status in hospitalized patients , 20. Amo2) is most commonly used for assessing nutritional status. BMI was calculated as weight (kg) divided by squared height (m2) [Body mass index  . If BMI P-value less than 0.05 was considered statistically significant.Quantitative variables with normal distribution were expressed as mean, standard deviation, and range. Quantitative variables with non-normal distribution were reported as median and range. Stratified variables were reported as frequency and percentage. Analysis of nominal qualitative data was performed by non-parametric tests such as the Chi-squared test. Mann-Whitney test was used for ordinal qualitative variables; for quantitative variables with normal distribution, t-test was run. Odds ratios (OR) were reported with 95% confidence interval. To identify independent risk factors logistic regression was used. A n = 1055) were male and 50% (n = 1054) were female. Demographics of the study population are shown in Table 2, respectively. In 8.72% (n = 183) of the patients, BMI was less than 18.50 kg/m2.Participant flow chart is presented in Fig. n = 479 cases), which is determined by combining the SGA-B  and –C  also 76.07% (n = 1523) of patients were identified as SGA-A .The nutritional data of the patients are presented in Table n = 799) of the respondents, of whom 217 subjects were well-nourished and 36 subjects were malnourished.Weight loss in the last 3 months was reported by 37.31% (P < 0.05). The highest prevalence of malnutrition was observed in burns department (77.70%), followed by cardiac Surgery (57.84%), and hematology departments (50.00%). The lowest number of patients with malnutrition was in the ophthalmology department (2.51%) , malignant disease , number of medications  and length of hospital stay  were independent risk factors for malnutrition. Age and disease type were not associated with malnutrition (P > 0.05).Analysis of factors which may have been associated with malnutrition shows male gender  . In EuroThe results of the present study are in line with those of a national study conducted in Germany using SGA that reported 28% of patients suffered from malnutrition. A study in European hospitals showed that the prevalence of malnutrition ranged between 10 and 50% depending on the studied region . A studyThere are various reports on the prevalence of malnutrition around the world globe, which might be due to features of the studied samples, the tool used to identify malnutrition, and the type of assessed centers. Moreover, it should be noted that the mean age of patients in this study (44.68 years) was less than other studies (63.93 years) performed in Australia and (52.21 years) Latin America, while age was shown to be an independent risk factor for malnutrition. Additionally, most patients in the present study did not have malignant diseases that could affect the prevalence of malnutrition.The present study did not demonstrate any association between age and malnutrition that could be pertinent to the low mean age of the samples 44.68 years) [ years 8 and incoThe current study was the first national survey of hospital malnutrition and associated factors in Iran public hospitals which used a valid and reliable tool for nutritional assessment malnutrition, however, there were some limitations such as didn’t assess of malnutrition trend during hospitalization, because of the cross-sectional design of the study, another limitation was assessment by different investigators in hospitals. In further studies status of nutritional care and management of patients can be assessed, also effect of interventional measures in decline and management of problem could be evaluated.The data of this study provide an overall and comprehensive illustration of the nutritional status of patients and identify groups at higher risk for malnutrition in Iranian university hospitals. Control and management of this problem need a structural approach that should contain all these aspects: 1- administration of a universal assessment to screening patients for nutritional risk to identify patients with or at risk of malnutrition, 2- handle multidisciplinary supportive nutrition care to provide appropriate nutritional therapy, 3- take measures to promote continuity of care after discharge from acute care hospitals. Notable, improve knowledge and consciousness of clinician’s team to consider malnutrition as a specific disease entity that concludes significant patient and economic outcomes and requires active management.This study revealed that almost 24% of patients in public hospitals suffer from malnutrition. Male gender, malignancy, polypharmacy, and length of hospital stay were identified as independent risk factors for malnutrition. While the present study cannot determine to what extent and how malnutrition affects the outcomes, there is evidence showing effects on outcome and health costs, in this regard screening and nutrition interventions can improve the results.Additional file 1. STROBE checklist for nutritional epidemiologic studies.


Recently, there is an increased number of studies that use 360° virtual reality (VR) video for medical and rehabilitative purposes. However, the 360° VR video experience for older adults has not yet been investigated. This study aimed to examine the validity of an 360° VR video-based immersive cycling training system (360° VRCTS) for older adults and to provide preliminary evidence of efficacy.We developed a new virtual reality training system using an immersive environment 360° VRCTS. Five healthy older adults  participated in this study. The system was tested in a single training session (biking for 20 min while viewing a 360° VR video scene through a large curved screen) to identify its strengths and weakness. The usability and acceptability of our system were measured using the system usability scale (SUS) and the simulator sickness questionnaire (SSQ).All participants successfully completed the session without any discomfort. The average score for the SUS was 94.60 , indicating high usability of the technology. The average score for the SSQ was 2.24 (standard deviation = 2.05), indicating that the system is well tolerated and has few side effects.The 360° VRCTS may be a useful indoor training system for older adults due to its easy manipulation, high usability, and limited cybersickness.KCT0003555, Registered February 25, 2019, https://cris.nih.go.kr/cris/index/index.do.Clinical Research Information Services (CRiS),  An increase in the population of older adults is associated with an increase in the prevalence of physical, psychological, and social problems. Additionally, medical expenses have increased substantially over time, putting a strain on national finances. The limited financial support for medical expenses of older adults has resulted in a paradigm shift from existing policies focused on the treatment of diseases to policies for disease prevention by promoting exercise and physical activity , 2.The World Health Organization (WHO) recommends outdoor activities, such as walking and cycling, for older adults aged ≥ 65 years . Indeed,Physical activities that can be performed indoors are, in most cases, aerobic exercises using treadmills or stationary bicycles. Stationary cycle training is advantageous in that it can be applied to frail older adults as a non-weight bearing activity, with less impact on the joints , 9. HoweVR is a 3D graphic-based technology that provides a realistic experience to users using 360° virtual environments (VEs) that allows them to interact with images on a screen through a variety of interfaces . ImmersiRecently, interest in 360° VR videos has increased. Most 360° videos are made of ultra-high definition (UHD) video, 4 K UHD class or higher, to produce panoramic video in all directions (360°) with one or more cameras, typically filmed in real world locations. Unlike standard video in which the viewpoint is fixed by the person shooting the video, the 360° VR video allows for the use an input device, such as a keyboard, mouse, or accelerometer, in order to arbitrarily set the intended viewpoint . As inteHowever, since 360° VR video content still uses either stationary video or video-based content, users can only passively view content and are not able to participate through interaction, which is one of the main characteristics of VR. Furthermore, 360° VR video has not solved the problem of cybersickness, since it is provided through immersive HMDs and mobile phone-type HMDs with tracking technology to control 360° VR video. Calogiuri et al. (2017) argued that in order to utilize 360° VR video properly, side effects such as cybersickness should be resolved .Therefore, this study aimed to develop a 360° VR video-based immersive cycling training system (360° VRCTS) that responds to the user’s head movement to reduce cybersickness in HMD as reported in previous studies. We hypothesized that 360° VRCTS would result in a user experience characterized by high satisfaction and low cybersickness.This study was designed as a feasibility study in which healthy older adults were eligible to participate. To evaluate the usability of the 360° VRCTS, this study recruited older adults residing in B city in Gyeonggi Province.Individuals 65 ≥ years of age without previous experience with VR participated in the study. The participants had no eye diseases, such as cataracts, glaucoma, central and peripheral nerve injuries, or cardiopulmonary disease. Individuals who had previously experienced dizziness, vestibulopathy, or cyber sickness were excluded. Participants self-reported their general characteristics and medical histories. The minimum sample size required for usability studies was 5 subjects . Five pa The study was approved by the Institutional Review Board of Sahmyook University. The trial was registered with the International Clinical Trials Registry Platform (KCT0003555). All participants were provided with an explanation of the purpose and risk of the study prior to preparation of the consent form, and written informed consent was obtained based on the revised Declaration of Helsinki (2013).To develop cycle content based on the physical, psychological, and mental characteristics of older adults, the content must be designed to have a realistic background composition and easy-to-use controls to enable the user to have visual immersion. The 360° VRCTS consists of a visual display, cycle interface, and immersive interface that can provide real-time visual feedback.All data were processed in Arduino  and sent to Unity 3D . The laptop allow manual pedaling speed using magnets placed on the pedal arm through the reed switch sensors. The MPU6050 sensor was mounted on a Bluetooth headset to recognize the movement of the user’s head and set the camera’s movement within the sphere, which was implemented in Unity.The visual display of the cycleway was created using the Unity 5 engine. Figure The cycle interface portion of the setup consisted of a stationary recumbent cycle  on which cycling was tracked as cadence, by a mechanism in which a small magnet attached to a pedal arm crossed a Hall effect sensor placed on the chassis. Every time the magnet crosses the sensor, the sensor triggers and outputs a signal, which signifies a complete rotation cycle of the pedal arm Fig. . SimilarThe latest immersive devices available on the market provide many features using a variety of technologies; however, they are not easy for older adults to use. For older adults, the function of the hardware interface should be minimized and designed to be easily handled by a user. Taking this into account, a control device using Arduino Micro was fabricated and attached to a stationary recumbent cycle so that the content could be run by simple selection Fig. .Fig. 3TTo provide maximum immersion and sense of reality, we matched the 360° cycle video speed with the stationary recumbent cycle speed whenever possible. Using a magnetic sensor attached to the main body of the stationary recumbent cycle, the RPM based on the pedal rotation was acquired as the speed signal data by the switch. The 360° video playback speed was adjusted by substituting the speed data measured by the stationary recumbent cycle pedals into the Unity video playback speed . Speed was defined by calculating the contact signal generation period between the disk that rotated when the cycle pedal was moved and the magnetic sensor attached to the cycle body and combining this with the running distance per unit time (2π * radius of wheel). Exercise time and RPM were displayed on the screen to encourage subjects to participate in the exercise  stationary recumbent seating cycle , Arduino Micro (ATmega32U4) controller, laptop , and Bluetooth stereo headset .All participants fasted for 2 h before the experiment to distinguish discomfort caused by post-meal exercise and cybersickness. The laboratory temperature was maintained at 24 °C, and exercise was performed under low light to facilitate focus on the screen video. After the researcher’s demonstration, participants were asked to perform all the experimental procedures. The participants performed non-VR warm-up cycles for 3 min before the start of the experiment. During the warm-up exercises, the researchers explained and demonstrated how and when the 360° VRCTS began and ended, and its inherent characteristics. Participants were told to watch the video by moving it up/down and left/right, since it was a 360° video. While freely cycling for 20 min, the participants experienced a 360° VR video-based cycle system, in which the video speed varied depending on the cycle speed and, although it was a video, the screen viewpoint changed when it was moved up/down or left/right. If participants felt excessive eye fatigue, repulsion, or cybersickness during the cycle, they were instructed to raise their hand at any time to indicate their intention to quit or press the end button on the 360° VRCTS to exit. A researcher was always positioned next to the participant to ensure a safe experience.At the end of the 360° VRCTS session, the researcher helped the participant end the recumbent seating cycle and led them to the room next to the laboratory. Participants rested until they fully recovered, and then filled out a questionnaire provided by another researcher.In this study, usability is the extent to which a user experiences the developed VR system to accomplish quantified goals satisfactorily, safely, and efficiently within a well-constructed context . We asseCybersickness is a side effect felt after experiencing VR and its symptoms include nausea and dizziness . The stiAll data were recorded on a Microsoft 2016 Excel Spreadsheet and descriptive statistics were used to calculate the mean and standard deviation (M ± SD) of clinical and demographic variables. The SUS scores were calculated using the Brooke (1996) method. Based on the method proposed by Kennedy et al. (1993), SSQ scores were derived from the overall symptom value  and the values of three symptom subgroups .Patient demographics and raw SUS and SSQ scores are shown in Table This feasibility study was aimed at investigating the usability and stability of an immersive cycle training system based on 360° VR video, which was developed to improve indoor physical activity for older adults aged ≥ 65 years. The results of our study are encouraging. SUS scores (94.60 ± 3.85) were very high, indicating high levels of acceptability, ease of use, learnability, and confidence when using the system. Cybersickness is one of the most common side effects in VR applications, but we found that our 360° VRCTS elicited only minor symptoms of nausea (3.82 ± 5.34) or disorientation (2.24 ± 3.85).In previous studies –33, VR cDespite VR advantages, more than 60 % of users experience cybersickness when encountering VR, which can lead to unpleasant experiences for the user and can reduce the duration of VR use . One stuAnalysis of the SSQ total score showed that the 360° VRCTS developed by the authors did not cause cybersickness or the effect was minimal. Examination of the subscores  showed that two participants, one male and one female, had nausea symptoms (sweating), and another female participant had disorientation symptoms (pressure felt in the head), but all symptoms were insignificant (slight). The head pressure felt by one of the participants was due to use of the headphones. Indeed, this participant did not report any symptoms in the other subgroups , so it is thought that the felt head pressure may indeed have been caused by headset-wearing problems rather than disorientation caused by the 360° VRCTS. A previous study examined differences in the user’s VR experience based on HMD weight . ParticiIt is noteworthy that our study showed no oculomotor symptoms in any of the participants. Cybersickness, unlike common motion sickness, is mainly caused by vision –44. AccoThis study included multiple efforts to reduce cybersickness. First, visual elements fixed in 360° VRCTS videos were inserted based on the rest frame theory. At the start of the video, the environment seen from the front of the cycle was set as the user’s point of view, with the play time displayed at the top of the screen and the RPM speed at the bottom. Even if the user turned his/her head, the play time and RPM speed were fixed on the front of the screen so that the user could recognize the front of the screen to stabilize the point of view during the video. Another way we attempted to reduced cybersickness was making it so that our content only allowed a single rotational axis movement whenever user tried to move on the 360° video screen by moving his/her head. For the y-axis movement, the screen moved only left and right by blocking the z-axis and x-axis movements. When the x-axis movement occurred, the screen moved only up and down by preventing movement of the y-axis and the z-axis.The purpose and content of VR can be divided into active and passive experience types. In previous studies, users who consistently experienced passive experiences reported more severe cybersickness –50. ThesOwing to the nature of VR technology, the most direct way to realize a high-fidelity environment is to maximize the visual reality of the video by using the best graphic technology. To create a high-immersion VR experience for the user, the developers tried to implement a VR that was very similar to the real world. However, despite the expectation that cybersickness occurrence would decrease as VR becomes more similar to the real world, cybersickness symptoms have been shown to be exacerbated by the addition of texture detail to increase the graphic sense of reality , 53, andFinally, we did not use an HMD, which is a display method used by existing VR systems, or a CAVE system that uses multiple monitors or large screens, instead we used a curved TV, which is a new method for displaying VR. In other words, the shape of the screen widens the FOV, and the user experiences an improved sense of depth. This effect results in optimum immersion for the user. In a previous study on the occurrence of cybersickness caused by a specific display device, serious cybersickness occurred not only with an HMD, but also with a large flat-panel screen . Unlike Currently, a widely used method to measure cybersickness is the questionnaire, which relies on subjective reporting by individuals. The questionnaire measurement has the advantage that it is intuitive, and anyone can easily complete it. However, since cybersickness symptoms are collected from the user at the end of the VR experience, adverse reactions cannot be collected in real time. There are also the issues regarding differences in the definition of cybersickness among different individuals. The questionnaire used in this study was the SSQ . HoweverThis study is based on the development of a method that provides immersive content for cycle training based on 360° VR video, and attempts to increase interest to motivate older adults to perform indoor exercise. Although the study consisted of only five older adults , the results were very encouraging. Participants were very motivated to use the 360° cycle content, and it did not cause cybersickness, the most common obstacle to using VR in an older adult population. In addition, there were no major difficulties for older adults when using the system and no special training was required, resulting in very high usability.Based on these results, we believe that our 360° VRCTS can be safely used as an indoor exercise tool for older adults. Future research should focus on developing various exercise protocols using 360° VRCTS and verifying their effects using a larger number of participants. Furthermore, in combination with wearable devices that have recently attracted attention in the healthcare market, we believe that even more advanced 360° cycle content could be provided in the future.


Advance directives (AD) are a crucial method for individuals to communicate their directions regarding medical decisions to their families and health care professionals when they are no longer able to make these decisions for themselves. However, not many individuals have an AD. We present the results of a survey-based experiment on how message framing  in educational videos affects (a) the individual’s decision to acquire more information about an AD and (b) the change in stated likelihood of obtaining an AD. Our message framing is centered on the family burden aspect of end-of-life care. We also survey participants about which type of framing they view as more persuasive in terms of obtaining an AD. We find that participants who watched the negative framed video were more likely to request more information about ADs. However, for those who had not sought information on ADs prior to the study, positive framing has a small positive impact on the approximate change in stated likelihood of obtaining an AD. On average, positive framing is perceived as more convincing to obtain an AD. Ranking the positive framed video as first or second in terms of convincingness is correlated with self-reported creation of an AD, whereas ranking the negative framed video as first or second is correlated with not creating an AD. Individuals make many decisions about their personal health care. How individuals make these decisions and influencing factors are critical to understand. Often health care decisions are complex, especially about end-of-life care. Applying behavioral economics techniques, such as framing effects and social norms, can assist researchers and clinicians to investigate and better understand individual decision-making to support desired health outcomes.A critical but difficult task in health care is to ensure that end-of-life care is consistent with patient preferences. Many Americans will need critical healthcare decisions made near the end-of-life but will lack the capacity to make those decisions themselves  used in medical offices have a query if the patient has a current AD. It is unclear what, if any, follow-up is done if the patient answers no  report in April of 2015, even though major healthcare institutions must have written policies about advance directives and their use, staff and patients remain challenged to discuss end-of-life care. This further affirms the need for strategies to achieve completion of ADs.Unfortunately, even though many people would prefer to die more peacefully at home, over 80% of deaths occur in hospitals or nursing homes and are often associated with painful, expensive high-tech treatment  in a recent national study were not being aware of what an AD is and believing that family members already knew what the individual’s wishes were  or that it has a 95% survival rate (positive or gain-framed). Prior studies of framing related to health have shown that positive frames are more effective for prevention, while negative frames are more persuasive for detection. Rothman and Salovey  found thMcNeil, Pauker, Soc, and Tversky  studied Social norms describes the phenomena in human behavior in which people’s actions are influenced by what they perceive those around them are doing. There are several studies that explore the effect of social norms on health decisions and related issues. Zimmerman  studied Akin to that, powerful stories about events that happen to others can be especially effective in motivating behavior rather than statistics, especially for those who are not quantitatively inclined. A person’s story has the power to affect human behavior more than ‘faceless statistics’ , which will be referred to as the informational video. They then were asked questions (Appendix B) related to their personal experience with ADs, such as whether they have ever sought information about ADs, whether they have ever spoken to family members about end-of-life care, and the reasons they currently do not have an AD.There is a 1 min and 28 s negatively framed video that features a brother, sister and sister’s husband in a hospital waiting room trying to make an end-of-life care decision for their father who is incapacitated and who did not have an advance directive. This family is in grief and worries over the decisions they should make given they don’t know their father’s wishes (we will refer to this video as negative framed video). See Appendix C for a transcript and link to this video.Another video is a 1 min and 7 s positively framed video that features the same family in the previous video. This time their father had an advance directive, so while in grief, they are relieved their father’s wishes are carried out (we will refer to this video as the positive framed video). See Appendix D for a transcript and link to this video.The final 1 min and 37 s video uses a social norm to frame the decision to make an advance directive.Next, participants saw one of three videos with different message framing around the family burden aspect of end-of-life care.Video scripts were developed by the research team and reviewed by a clinical expert panel (5 nursing faculty experts). Videos were rated as to clarity and quality of message. Content validity was established at the 100% level. Additionally, a classroom pilot study of 35 students in a Master’s Economics class was conducted to obtain and analyze video ratings. Content validity was confirmed. The videos used professional actors and were approved by the UTA IRB.Participants were randomly divided into three groups, which we will refer to as conditions. Individuals assigned to each condition saw the videos in a different order as described in www.caringinfo.org). They were also offered the opportunity to set up a free AD at mydirectives.com.In each condition, after participants viewed their first video (and were unaware of other videos coming), they were asked questions (Appendix F) about the video and their opinion of its effectiveness in motivating to obtain an AD. They were also asked if they would like more information on advance directives. If they indicated they would, they were given the opportunity to learn more about ADs and end-of-life planning through a link at the end of part one of the survey that directed them to the National Hospice and Palliative Care Organization’s website .Part two of the study consisted of a brief follow-up survey conducted about one month after part one of the study, to determine if attitudes about ADs had changed and if participants had taken any self-reported actions surrounding ADs, including whether they had obtained an AD. Questions are available in Appendix J. For the follow-up survey, Qualtrics contacted all initial participants, and stopped the follow-up after 562 participants completed the follow-up study. The sample size of the follow-up survey was dictated by practicality  and budget.Our design intentionally has a within and between participant design. In the initial survey, participants indicate their interest in receiving more information about an advance directive and their likelihood of creating an AD after only seeing one framed video. Hence, we are able to analyze which frame , if any, affected these outcomes. Because of the random assignment to each condition, the relationship between framing type and these outcomes can be interpreted causallyIn part two, the follow-up survey, we were able to see if the videos in the initial survey nudged participants to obtain an advance directive. Because participants had seen all videos at this point, we cannot interpret any causal relationship between type of framing and self-reported obtainment of an AD. This design, of course, limits our ability to distinguish which type of framing is the most effective in convincing participants to obtain an advance directive. We decided obtaining participants’ ranking of the videos was important to do in part one because of our uncertainty of return rates for part two of the survey. Since we are at the beginning of this type of research , we decided obtaining a ranking of how convincing the videos are in relation to each other was important even though we lost some control in determining exactly which video prompted action beyond wanting to learn more information. We plan to address this and other related questions in subsequent projects.In addition to the variables of interest in the table above, we also consider a number of independent variables as controls. The continuous control variables include age and number of children. The categorical control variables include dummy variables for gender, relationship status , race , Hispanic heritage, educational attainment , self-reported health status , whether or not have a chronic health issue or disease, whether or not have health insurance, political views , frequency of church attendance , and reasons don't have an AD Independent Variables of Interest: Model 2: The second model is an OLS regression to determine if a relationship exists between message framing and a change in the stated likelihood of obtaining an AD. The initial likelihood is measured after watching the informational video, and the second stated likelihood is measured after watching the first framed video.Dependent Variable: ADdiff = ADLikelihood - SeekLikelihoodIndependent Variables of Interest: Condition 1, Condition 2 (Condition 3 is the base category)Models 3a, b, c: The third model is an ordered probit for each video to determine what factors are correlated with perceived convincingness to obtain an AD. The ranking of perceived convincingness was measured after watching all three framed videos.RankDependent Variable: Models 4a, b, c: The fourth model is a probit to determine what factors are correlated with self-reported creation of an AD after the initial survey but before the follow-up survey. One of these factors is how participants ranked the videos in terms of convincingness. We also estimate probits for those who did not create an AD, to determine what is correlated with having reported speaking to someone about an AD and stating that an AD will be created someday or soon.Dependent Variables: CreatedAD, SpokeAboutAD, WillCreateADIndependent Variables of Interest: Dummy variables for ranking negative framed video as most convincing and ranking positive framed video as most convincing, with ranking social norm video as most convincing as base category Model 1: The first model we estimate is a probit model, to determine if a relationship exists between message framing and wanting to know more information about ADs after watching the first framed video.Demographic data validate a diverse sample across ages, race/ethnic, and education levels. It is noted that the high percentage of females may be influenced by the older age groups in the sample. Eighty percent of the sample rated their health as good to excellent. Only one-third of the sample reported a chronic disease. Overall, the sample may be healthier than expected and this may be related to individuals who choose to participate in Qualtrics studies. In general, participants tended to an internal locus of control. They were more mid-point regarding risk-taking preference and present vs future orientation.ADlikelihood)How likely are you to ever obtain an advance directive, after seeing this video? Ranging from ‘Not At All Likely’ (1) to ‘Very Likely’ (5), please select one. (WantInfo)Would you like more information about advance directives, including how to set up a free advance directive? If so, we will provide that information at the end of the survey. (Yes/No) . The highest likelihood is associated with the social norm video, followed by the positive framed video and then the negative framed video. However, these differences are not statistically significant, according to a Bonferroni multiple-comparison test .WantInfo). There are statistically significant differences between the three condition groups in the proportion who chose to receive more information after viewing the first video, according to a Bonferroni multiple-comparison test .A higher percentage of the participants who viewed the negative framed video first indicated they wanted more information on ADs than any other video (SoughtInfo). Approximately 25% had done so prior to participating in our survey.Recall that after the informational video, but before seeing the first framed video, participants were asked if they had ever sought information about ADs (WantInfo) and whether a participant had sought information on ADs prior to our study (SoughtInfo). Of those who had sought information prior to our study (n = 286), 50% wanted more information about creating an AD after watching the first framed video, and 50% did not. Of those who had not sought information prior to our study (n = 874), 40% wanted more information after watching the first framed video, and 60% did not. So, those who had sought out information prior were 10 percentage points more likely than others to be information seekers after watching the first framed video.There is a relationship between wanting more information about creating an AD after viewing the first framed video (ADlikelihood) and whether a participant had sought information on ADs prior to our study (SoughtInfo). For those who had sought information prior to our study, the mean value of ADlikelihood is 3.95. For those who had not sought information prior to our study, the mean value of ADlikelihood is 3.6. Thus, the stated likelihood of obtaining an AD after watching the first framed video is higher for those who had already been information seekers.There is also a relationship between stated likelihood of obtaining an AD after watching the first framed video (n = 874) were asked the following: How likely are you to ever seek information about creating an advance directive, on a scale of Not at All Likely (1) to Very Likely (5) (SeekLikelihood). We can use the question about likelihood of obtaining an AD after watching the first framed video (ADLikelihood) to assess a change in attitudes.Respondents who had not sought any information on ADs prior to the study , since the assignment to groups was random and this question was asked prior to seeing any framed videos. We see slightly less variation in the mean of ADlikelihood across conditions, but these are not statistically significant . However, we do see variation in the difference of the means by condition, with the positive framed video having the largest increase in likelihood of obtaining an AD, followed by the social norm video. There was virtually no change associated with the negative framed video. This variation in the differences of the means is not statistically significant, according to a Bonferroni multiple comparison test . If we compare the difference in the means for two groups, those who saw the positive framed first and everyone else, the null hypothesis that the means are the same can be rejected at the 9.6% level  and at the 4.8% level .p < .001) compared to those who saw the positive framed video first. The coefficient for those in condition 2, who saw the social norm video first, is positive but not statistically significant. Therefore, compared to those who saw the positive video first, we can’t be sure that those in condition 2 are more likely to want more information about ADs.Appendix K shows our probit estimation results for wanting more information about ADs after viewing the first framed video (Model 1). The regression contains dummy variables for condition 1 and 2, with condition 3 being the base category. The results are consistent with the findings in p-value of .10 or less as a benchmark for statistical significance, several other variables are correlated with wanting more information about ADs. Those who have already spoken to their family about their end-of-life wishes are almost 10 percentage more likely to want more information about ADs compared to those who have not spoken to their family. Those who have had to make decisions about someone else’s end-of-life care are about 7 percentage points more likely to want more information about ADs than someone who has not been involved in these types of decisions for another person.Using a Most stated reasons for not having an AD were positively and statistically associated with wanting more information after watching the first framed video , with the exceptions of reporting that telling family end-of-life wishes is enough, doctor never discussed ADs, and ‘other’ category. Church goers also wanted more information on end-of-life care, relative to those who do not attend church. In addition, those who believe they have a great deal of choice over their life are significantly more likely to want information about an advance directive. Number of children is positively correlated with wanting more information. However, other demographic variables like race, gender, and age are not statistically significant.ADdiff (ADLikelihood – SeekLikelihood) for those who reported not having already sought information on ADs prior to participating in the study. This approximates the change in stated likelihood of obtaining an AD, from after watching the informational video to after watching the first framed video. Since ADLikelihood and SeekLikelihood are measured on a 1–5 scale, the difference ranges from −4 to 4, with the negative values corresponding to a decrease in likelihood and a value of 4 corresponding to the largest increase in likelihood.Appendix K also presents the OLS regression results for ADdiff, relative to seeing the positive framed video. Though seeing the social norm video first has a negative coefficient as well, it is not statistically significant. Thus, those who saw the positive framed video on average have a higher value of ADdiff compared to those who saw the negative video first, which means a higher approximate change in the stated likelihood of obtaining an AD. This is consistent with the summary statistics in We find that which video was seen first has a statistically significant but small effect on this change. Seeing the negative framed video has a negative effect on ADdiff. Age has a statistically significant but small impact on the change, with age slightly increasing the stated likelihood of taking action on ADs. Giving the reason of not having an AD because the participant didn’t know about them until now and because no one has encouraged them to get one also have positive and significant effects on the approximate change in stated likelihood of obtaining an AD. On the other hand, having already spoken to family members has a significant and negative impact. Having moderate or conservative political view relative to other views also has a negative impact, as does being more willing to take risks.A few control variables also statistically affect Result #1: Negative message framing about the family burden aspect of end-of-life care statistically increases the choice to obtain more information about advance directives. For those who had not sought information on ADs prior to the study, positive framing has a small positive impact on the approximate change in stated likelihood of obtaining an AD.The above analysis leads us to the answer to our first research question:Our within participant design results focus on how convincing participants perceived the framed videos to be. After viewing all three of the framed videos, participants were asked to rank the videos in order of how convincing they were (1 being the most convincing and 3 being the least convincing).z = 2.09, p = 0.037 and z = 3.87, p = 0.0001, respectively).Examining Result #2: On average, the positive messaging about the family burden aspect of end-of-life care is perceived as more convincing to obtain an AD, but more participants perceived negative messaging as most convincing over every other video.In fact, findings regarding the negative framed video seem to be quite polarizing. Most either ranked it at most effective (37.24%) or least effective (35.6%) as opposed to in the middle (27.16%). We also note many participants ranked the positive framed video as second (45.09%), which increased the positive video’s average rank. So, while on average the positive framed video ranked as more convincing, a larger number of participants ranked the negative framed video first, as the most convincing. Thus, we have the answer to our second research question.To further discern what significantly affected participant’s ranking of the videos, we estimate an ordered probit regression for the rankings of each of the videos. The results are in Appendix L. Most variables do not have a significant impact on how each video is ranked.Age does significantly affect ranking of the positive and negative framed videos. For the negative framed video, the positive coefficient on age indicates that as age increases, participants are more likely to rank the negative framed video with a higher number; in other words, older participants rank it as less convincing. For the positive framed video, age has a significant but negative effect. This means that the older a participant is, the more convincing they perceive the positive framed video. Thus, older participants found the positive framed video more convincing than the negative framed video. This result is relevant because the GAO Report  found agCorollary to Result #2: Positive messaging around the family burden aspect of end-of-life care is perceived as more convincing the older participants are, while the negative messaging is perceived as more convincing the younger participants are. Those with a chronic disease find social norm messaging involving someone without an ailment as more convincing, while those who are cohabitating find it less convincing relative to individuals who have never married.Those who are cohabitating but not married rank the negative framed video as more convincing and the social norm video as less convincing, relative to those who have never married. In addition, the dummy variable indicating if a person has a chronic disease statistically affects how the social norm video is ranked. Chronic disease has a negative coefficient, so a participant is more likely to view the social norm video as more convincing if they have a chronic disease.Of the 1,160 participants who participated in part one of the study, 562 answered our questions in part two of the study about one month later, the follow-up survey. Of the 562 participants, 106 (18.86%) self-reported they had created an advance directive.If participants reported they had not created an AD, they were asked if they had talked to anyone about creating their own AD, and if so, to whom they had talked. Of these 455 part two respondents, 113 reported talking to someone about creating and AD. The vast majority, 80% talked to a family member, 9% talked to a medical provider, over 3% to a lawyer, and about 8% to someone else such as a friend.The 455 participants who reported creating an AD were also asked if they planned to create one. About 14% said no, almost 7% said probably not, 35% said they had not decided, 33% said yes (someday), and almost 11% said yes (soon).order impacts whether or not someone obtained an AD, that effect can be interpreted causally. In other words, if we find a significant effect of which video was seen first (same as condition) on AD completion, then that must be viewed as an order effect.We present this information to explore a possible order effect. Which framed video participants saw first only has a causal interpretation on outcomes measured after the first framed video was seen (such as wanting more information about ADs), not on outcomes measured after all framed videos were seen (such as obtaining an AD). However, since participants were randomly assigned to each condition, if video p = 0.86). Nor are there differences between the conditions in the percentage who spoke to someone about an AD  or the percentage who said they would create an AD . Therefore, we find the order participants viewed the videos had no effect as to whether participants created an AD. This is not surprising because participants viewed all three videos in a very short amount of time.There are no statistically significant differences between the three conditions in the percentage who created an AD, according to a Bonferroni multiple-comparison test  by a fairly small margin compared to the positive framed video (34%). Again the positive framed video was most likely to be ranked in the middle in terms of being convincing (44%) and least likely to be ranked least convincing (22%) by quite a large amount.Looking down the columns of Thus, rating the positive framed video as convincing is correlated with reported action to create an AD. Another way to see the trend is in Not all of the participants who reported creating an AD in the follow-up survey had indicated they wanted more information after watching the first framed video in part one of the study. In fact, 55 of the 106 participants who reported obtaining an advance directive (51.89%) indicated they did not want additional information after the first framed video. Of those who reported creating an AD, 36 had sought information on ADs prior to participating in the study, and 22 had both sought info previously and wanted more information after watching the first framed video.A possible reason 51.89% of the participants that reported creating an advanced directive indicated they didn’t want additional information about ADs is they were already convinced to obtain one by the time they got to the end of the first framed video and didn’t need to spend the time reading additional information.ADLikelihood) and wanting more information on ADs (WantInfo), for those who indicated they created an AD, is shown in We return to a question asked of participants after they viewed their first framed video: ‘How likely are you to ever obtain an advance directive after seeing this video?’ A comparison between likeliness to obtain an AD . They saw the positive framed video first, and recall that at this time had only seen the positive framed video. This is also the only condition in which more participants indicated they did not want more information despite the fact that, of the 24 who said they did not want more information, 19 responded with a 3 or higher that they would be likely to create an advance directive after viewing this video. We’ve already seen that those who reported creating an AD ranked the positive video as most convincing, on average. Hence it is very possible that one reason the majority of the participants who reported creating an AD said they did not want additional information is they had already been convinced to create one. Additional research is needed to draw definitive conclusions.CreatedAD to investigate factors that may have affected whether an AD was created, for the participants who returned for part two of the study. Ranking the negative framed video as most convincing significantly decreases the likelihood of creating an AD. Thus, those who ranked the positive framed video and social norm video as most convincing are more likely to create an AD. Having sought information about ADs (SoughtInfo) prior to participation in part one of the study significantly increases the probability of obtaining an AD, by about 12 percentage points. Those who stated in part one of the study, prior to watching any framed videos, that they did not have an AD because they had made their wishes known to their family are more likely to report having created an AD.Several characteristics are correlated with self-reported AD creation. Appendix M reports the results of a probit regression with dependent variable age is negative and statistically significant; thus, the older a participant, the less likely they are to have created an advance directive. Females are less likely to report creating an AD. We find race to significantly affect the probability of creating an AD. White participants are more likely to complete an AD, relative to non-white, non-black participants. We also find black participants to be more likely to complete an advance directive than white participants and those of other races.Several demographic variables are statistically correlated with self-reported AD creation. The variable We also estimate probit models for whether or not participants reported having spoken to someone about ADs since the initial survey, and whether they said they will create an AD either someday or soon (Appendix M). Those who had already sought information about ADs prior to the study, spoken to family members prior to the study, and had been involved in deciding end-of-life care for someone else were more likely to have spoken to someone about ADs between the initial survey and the follow-up survey. Having sought information has the largest impact, increasing the probability of speaking to someone between surveys by over .25 percentage points.Result #3: Those who ranked the positive framed video and social norm video as most convincing were more likely to self-report creating an AD. Several other factors are positively correlated with self-reported AD creation, including being black and white (relative to other races) and choosing ‘my family knows my wishes’ as a reason to not have an AD prior to viewing the framed videos.Similarly, having previously sought information and having previously spoken to someone about ADs also significantly affects the likelihood that the participant said they would create an AD someday or soon in the follow-up survey. In addition, wanting for information after the initial video did have a positive impact on reporting AD creation would happen someday or soon, increasing it by about .18 percentage points.We present the results of a survey-based experiment on how message framing on the family burden aspect of end-of-life care is correlated with decisions around advance directives and perceived convincingness to obtain an AD. We find that negative message framing about the family burden aspect of end-of-life care is positively correlated with the choice to obtain more information about advance directives. However, the negative messaging was somewhat polarizing, with more people ranking it as least convincing than ranking it in the middle. For those who had not sought information on ADs prior to the study, positive framing has a small positive impact on the approximate change in stated likelihood of obtaining an AD. On average, positive framing is perceived as more convincing to obtain an AD. Last, ranking the positive framed video as first or second in terms of convincingness is correlated with self-reported creation of an AD, whereas ranking the negative framed video as first or second is correlated with not creating an AD. Social norm messaging is also positively correlated with self-reported obtainment of an AD.Negative framing may be most effective in encouraging information acquisition as opposed to action, while positive framing may be most effective in encouraging action as opposed to information acquisition. If we view obtaining an AD as preventing against bad circumstances in the future, then this result is consistent with the literature that finds that positive or gain-framed messaging is more effective at promoting prevention behaviors, such as Rothman and Salovey . HoweverPositive messaging around the family burden aspect of end-of-life care is perceived as more convincing the older participants are, while the negative messaging is perceived as more convincing the younger participants are. Older adults have been found to focus more on positive messages and emotionally positive goals as they age (Carstensen, Perceptions of how convincing the types of framing are also depend on whether an individual has a chronic disease, such that those with a chronic disease find social norm messaging involving someone without a chronic ailment as more convincing. This is an interesting result because the social norm video specifically mentions that the third party who passed away had no ailments. It is possible those with ailments find the video that specifies the participant had no ailments as more convincing. More analysis is needed to draw firm conclusions about this issue. In addition, those who are cohabitating but not married rank the negative framed video as more convincing and the social norm video as less convincing, relative to those who have never married. It could be that these participants are more likely to ignore social conventions in various aspects of their lives.Those who stated in part one of the study, prior to watching any framed videos, that they did not have an AD because making their wishes known to their family was enough were more likely to report having created an AD. Rao et al.  stated tDemographic results for participants who requested additional information about ADs and reported obtaining ADs did not generally support current literature. The GAO Report  found thWe also find that black individuals are more likely to report AD completion, compared to other races. This finding is interesting in conjunction with those of Kwak and Haley , who sugThis study is exploratory in nature and not without limitations. There is some variation in the length of the videos, which is a potential confounding variable. It is possible a slightly longer video may have more impact on decision making. However, we do find that the shortest video, the positive framed one, is correlated with several positive outcomes, such as having a small positive impact on the approximate change in stated likelihood of obtaining an AD, being ranked as most convincing on average, and being correlated with self-reported AD creation.In addition, we did not have a condition in which a group of participants watched only the informational video and not any framed videos. Thus, we can’t say that the framed videos alone had a causal impact on the decision to request more information about ADs. Rather, it would be the combination of the informational video and the framing that would have a causal impact. Some participants may have already decided they wanted more information after watching the informational video and before watching the first framed video. However, we do ask participants after the informational video how likely they are to seek information about creating an AD, if they had not already sought information, and are able to leverage this to look at a change in this attitude once they watch the first framed video.The decision to obtain an advance directive is important to limit the high costs of end-of-life medical care, the emotional and possible financial strain on families, and the possibility that someone does not get the healthcare they desire when they are unable to make their wishes known. This study adds to the sparse literature regarding use of behavioral economics to explore framing effects on decision making around ADs. It has provided several avenues for further research and can inform future studies in a clinical setting. Further studies of behavioral economics and framing can continue to assist policy makers and the medical community in providing the best care possible tailored to the wants and needs of each individual patient.


N = 6799, 4th, 6th, and 8th-grade students). Adolescents answered questionnaires examining the time spent playing video games, per day, on weekdays  and ACEs (eight types). Results: The results of the ordinal logistic regression analysis showed a positive association between ACE total score and time spent playing video games after adjusting for covariates . Regarding each type of ACE, the experiences of single parenthood, parental history of psychiatric disorders, and peer isolation were independently positively associated with time spent playing video games. Conclusions: Health policy to address ACEs might be important to shorten the time spent playing video games.Background: Excessive time spent playing video games is associated with adverse health outcomes in adolescents. Although poor child–parent relationship and social relations with peers are considered as possible predictors, little is known as to whether adverse childhood experiences (ACEs) are associated with time spent playing video games. The aim is to examine the association between ACEs and time spent playing video games in adolescents. Methods: We used pooled data from the Adachi Child Health Impact of Living Difficulty (A-CHILD) study in 2016 and 2018, which is a population-based cross-sectional study in Adachi City, Tokyo, Japan ( Excessive time spent playing video games in children and adolescents has been a public health issue globally. The American Psychiatric Association has defined “Internet gaming disorder (IGD)” which refers to “persistent and recurrent use of the Internet to engage in games, often with other players, leading to clinically significant impairment or distress” in the Diagnostic and Statistical Manual, Fifth Edition DSM-5) . The Wor . The WoPrevious studies have shown several predictors for excessive time spent playing video games in adolescents including problematic video gaming and IGD. The systematic review, which identified predictors for problematic video gaming in adolescents, showed that a poor quality of parent–child relationship  might predict problematic video gaming . AnotherACE is defined as childhood experiences before the age of 18 years including parental loss, household dysfunction such as parental divorce, and child maltreatment such as physical abuse and neglect . A recenN = 4654; sixth grade: N = 1016; eighth grade: N = 1129)  study in 2016 and 2018, which is a population-based cross-sectional study in Adachi City, Tokyo, Japan. The details of the A-CHILD study protocol are available from the protocol paper of the A-CHILD . In 2016 = 1129) .ACEs consist of the following eight types, which were based on a previous study : single Single parenthood was assessed on the caregiver’s questionnaire with a question about living with family members. When family members living together did not included a mother or father, single parenthood was coded as “1”. Parental history of psychiatric disorder was assessed by two questions  on the caregiver’s questionnaire. When the caregiver reported either maternal or paternal history of psychiatric disorders, parental history of psychiatric disorder was coded as “1”. Physical and psychological abuse, witness to domestic violence, and neglect were assessed via the caregiver questionnaires using seven items on a scale of 1 = “often”, 2 = “sometimes”, 3 = “rarely”, and 4 = “not at all.” Physical abuse was assessed from two questions: “hit the child’s body ”, in which the responses were dichotomized with “often” equated to a “yes” response, and “beat the child,” in which the responses were dichotomized with “rarely”, “sometimes”, or “often”, which equated to a “yes” response. When either item was classified as “yes,” physical abuse was coded as “1”. Psychological abuse was assessed by two questions: “yell at the child,” in which the responses were dichotomized with “often” equated to a “yes” response, and “insult the child repeatedly”, in which the responses were dichotomized with “sometimes” or “often”, which equated to a “yes” response. When either item was classified as “yes,” psychological abuse was coded as “1”. Witness to domestic violence was assessed by the question “have a big fight in front of the child,” in which the responses were dichotomized with “sometimes” or “often”, which were both equated to a “yes” response. Neglect was assessed by two questions: “shut the child outside” and “do not feed the child,” in which the responses were dichotomized with “rarely”, “sometimes”, or “often”, which equated to a “yes” response. When either item was classified as “yes”, neglect was coded as “1”. This coding was developed in a previous study . Low houThe amount of time spent playing video games on weekdays was measured by the adolescent questionnaires. Adolescents assessed the item on a scale of 1 = “not at all”, 2 = “30 min”, 3 = “1 h”, 4 = “1 h and a half”, 5 = “2 h”, 6 = “2 h and a half”, 7 = “3 h”, and 8 = “more than 3 h”. In this study, “not at all”, “30 min”, and “1 h” were categorized as “1” (less than 1 h), “1 h and a half”, “2 h”, “2 hours and a half”, and “3 h” were categorized as “2” (less than 3 h), and “more than 3 h” was categorized as “3” (more than 3 h).Covariates were the child’s sex, number of siblings, grade in school, and maternal age, which were measured via the questionnaire. These variables were selected as covariates because the child’s sex and maternal age were used as confounders in previous studies that examined the association between ACEs and addictive mobile phone use  and the This study was conducted according to the guidelines of the Declaration of Helsinki and approved by the institutional review board of the Tokyo Medical and Dental University (M2016-284).In the analyses, the cumulative ACE total score was calculated using all eight types and collapsed as 0, 1, 2, and 3+ due to the small sample size for 4+ cases . Each type of ACE was used in the separate analysis. Ordinal logistic regression analysis was performed to examine the association of the cumulative number of ACEs and each type of ACE with time spent playing games . After estimating the crude model, we examined the association between the cumulative number of ACEs and time spent playing games, adjusting for the child’s sex, grade in school, number of siblings, maternal age, and child’s school (Model 1). As for each type of ACE, Model 2 adjusted for child’s sex, grade, number of siblings, maternal age, and child’s schools. Model 3 included types of ACEs that were significant in Model 2. All analyses included the missing data as dummy variables and were weighted for the number of responses in each grade. We conducted all analyses using STATA version 15.0 SE. These analyses were not pre-registered.p < 0.001).p for trend < 0.001). After adjusting for covariates, the odds ratio (OR) of ACEs was significant . Regarding each type of ACE, the ORs of single parenthood , parental history of psychiatric disorders , peer isolation , and lower household income  were significant after adjusting for covariates. In Model 3, which added not only covariates, but also types of ACE that were associated with time spent playing video games , it was found that single parenthood , parental history of psychiatric disorders , and peer isolation  were independently associated with time spent playing video games.The results of the ordinal logistic regression analysis are shown in The current study found a positive relationship between the cumulative number of ACEs, which included the experiences of peer isolation and lower household income, and more time spent playing video games among Japanese adolescents. Specifically, adolescents living in single-parent families, adolescents who had parents with a history of psychiatric disorders, and adolescents with the experiences of peer isolation were more likely to spend time playing videogames per day on weekdays than those without such experiences. These three types of ACE were independently associated with longer amounts of time spent playing video games. Even though there is no consistent and standardized definition of excessive time spent playing video games, a previous study showed that adolescents who categorized as clinical group of IGD spent 27.8 h (SD = 13.3), those at risk of IGD spent 20.8 h (SD = 16.3), and those without problems spent 4.8 h (SD = 8.1) playing video games per week . The catOur findings, which had a positive relationship between ACEs and time spent playing video games, were consistent with the results of a previous study focusing on problematic video gaming among gamers . ACEs miThe positive association between the cumulative number of ACEs and time spent playing video games in adolescents may be explained by the following psychological and biological mechanisms. In terms of psychological mechanism, attachment style or child–parent relationship may mediate the association between ACEs and longer time spent playing video games. The previous systematic reviews regarding adolescent problematic gaming indicate that a poor parent–child relationship is a critical risk factor for problematic gaming including IGD ,36,37. AIn terms of biological mechanism, structural and functional brain alterations  might meThe current study has the following limitations. First, we cannot suggest a causal relationship between ACEs and time spent playing games due to the cross-sectional study, that is, reverse causation is likely. As for peer isolation, adolescents who spend longer amounts of time playing games might struggle with having friends with whom they can consult. Further longitudinal studies that examine the causal relationships are needed. Second, sexual abuse was not included in ACEs. In Japan, the prevalence of sexual abuse is low (0.5%)  and sexuTo prevent longer times spent playing video games in adolescents and eventually to prevent IGD and GD in children and adolescents, the development of self-regulation skills might need to be addressed in schools , targetiWe found that the cumulative number of ACEs was associated with longer time spent playing video games in adolescents. Regarding the types of ACEs, single parenthood, parental history of psychiatric disorders, and peer isolation were independently associated with longer times spent playing video games. To develop a population approach program designed to prevent longer times spent playing video games in adolescents, it may be needed to assess not only family background and relationships with their peers.