Association between Proximity of the Elementary School and Depression in Japanese Older Adults: A Cross-Sectional Study from the JAGES 2016 Survey

Depression among older adults is one of the most critical public health issues. The proximity of elementary schools has been positively associated with neighborhood social cohesion and quality of life. However, no studies have identified an association between the proximity of elementary school and older adults’ mental health. Therefore, this study aimed to examine the association between the proximity of elementary schools, one of the core facilities of neighborhood communities in Japan, and depression in older adults. A total of 131,871 participants (63,430 men 73.7 ± 6.1 years, 68,441 women 73.8 ± 6.2 years) were analyzed from the Japan Gerontological Evaluation Study (JAGES) 2016 survey. Logistic regression analysis showed that there was no association between distance to elementary school and depression among males. However, among females, compared with the participants living within 400 m from the nearest elementary school, the odds ratio of depression for those living between 400 and 799 m and more than 800 m away were 1.06 (95% confidence interval (CI) 1.00–1.12) and 1.07 (95% CI 1.00–1.15), respectively. The findings may be useful when considering the design of communities around elementary schools and the planning of facilities as a population-based approach to promote mental health of older women.

Introduction
The incidence of depression is increasing worldwide, and a World Health Organization (WHO) report estimated that more than 300 million people, equivalent to 4.4% of the world's population, had depression in 2017. The total population with depression increased by 18.4% between 2005 and 2015 [1], and its prevalence is exceptionally high among older adults [1]. The age-standardized incidence of depression worldwide is also increasing in regions with higher sociodemographic indicators [2]. Depression significantly reduces the quality of life and increases the risk of suicide, dementia, functional decline, elder abuse, and disability in older adults [3][4][5][6][7], and constitutes a significant public health issue.
In 2006, the WHO advocated for primordial prevention by recommending a change of attitudes, behaviors, and social values, which can be achieved by encouraging positive health behaviors, preventing the adoption of risk behaviors, eliminating established risk behaviors, and promoting the concept of health as a social good [8]. Primordial prevention requires a population-based approach, which targets the whole population irrespective of the risk level, and this is different from the high-risk approach, which focuses only on individuals or population groups with the highest risk of disease. In addition, it must confront the social, cultural, and community aspects of increased risk. Moreover, population-based approaches achieve considerably greater health gains than high-risk approaches due to the larger number of people involved [9].
These trends have intensified research on neighborhood environments that improve health [9,10]. There are many reports on the relationship between neighborhood environment and physical health, such as the impact of parks, sidewalks, or other built environments on physical activity and obesity rates [11,12]. There have also been studies on how the neighborhood environment affects mental health in older adults [13]. For example, the neighborhood built environment comprising high walkability, better access to transportation and destinations, better street connectivity, traffic safety, large amount of greenspace, and the social environment, such as high local social capital, is possibly related to improved mental health in older adults [14][15][16][17][18][19].
To develop a healthy neighborhood environment, the WHO has published the agefriendly cities guide that promotes active aging of older adults [20]. This guideline has indicators such as the accessibility of destinations, traffic safety, and social inclusion, and recommends the use of community facilities such as schools and recreation centers by all community members, including older adults, to help them participate in community activities and intergenerational exchange [21]. This implies that elementary schools can be considered components of age-friendly cities.
However, the relationship between elementary schools and the health of older adults has not been sufficiently studied. For example, the proximity to an elementary school, which represents the distance between the elementary school and the place of residence, has been shown to enhance neighborhood social cohesion as a place for increased interaction and group activities, improved quality of life, and increased children's physical activity [22][23][24][25][26]. These participants may encompass the entire population of residents, including older adults and children. Furthermore, none of the previous studies examined the relationship between proximity to an elementary school and older adults' health, particularly depression.
Therefore, we hypothesized that proximity to an elementary school might be associated with improved mental health of older adults. In Japan, elementary schools are one of the core facilities of a neighborhood community and are often used for local events, such as elections and athletic events, which may enhance social capital that is said to be associated with the health of individual or community health. In addition, the vicinity of the elementary schools may influence the safety of elementary school children on their way to and from school. Furthermore, people residing near elementary schools have many potential opportunities for daily contact with children, such as seeing, hearing, and talking to elementary school students on their way to and from school, which may promote intergenerational exchange. The purpose of this study was to examine the relationship between proximity to elementary schools and depression among Japanese older adults.

Population and Settings
This study used cross-sectional data from the Japanese Gerontological Evaluation Study (JAGES) conducted in 2016 [27]. JAGES is an epidemiological research-based project conducted every 3 years from 2010 and focuses on older adults from different regions across Japan. It aims to build scientific evidence on the role of preventive medicine in a healthy aging society. Participants were older adults in a community (age ≥65 years) who did not have physical or cognitive disabilities and had not received a certification of long-term care [27,28]. Thirty-nine municipalities in 19 prefectures across Japan participated in this research project. The survey was a self-administered questionnaire that was returned by postal mail from October 3 to December 5, 2016. The questionnaire forms were distributed to participants via the local government. Although the local governments were not randomly selected, they covered a wide range of characteristics in terms of region and population size in Japan. The questionnaire examined health status, psychological status, social support, social participation, hobbies, frequency of outings, life habitats, and demographic information, including sex, age, education level, equivalent income (annual household income), marital status, living arrangement, self-reported socioeconomic status, etc. A total of 180,021 data points (response rate: 70.2%) were identified in 2016. We excluded older adults who did not live independently with regards to their daily living based on their response to the following questions evaluating independence of activities of daily living (ADLs): "Do you regularly receive care and assistance for walking, bathing, toileting, etc.?"; the responses included (1) does not need care or assistance, (2) needs care or assistance but does not receive it, and (3) needs care or assistance but does receive it. We defined (3) as being dependent for activities of daily living [29]. A total of 131,871 individuals without missing data for the outcome (i.e., depression) and residential information for the explanatory variables were included in the analysis.

Outcome Variable
The outcome variable was depression. A short version of the Geriatric Depression Scale (GDS-15) was used to identify depression, which was indicated by a GDS-15 score of 5 or more in this study [30,31].

Explanatory Variable
The explanatory variable was the distance from the respondents' place of residence to the nearest elementary school. For accuracy, we used the latitude and longitude of a representative point in the city-level location reference information provided by the Ministry of Land, Infrastructure, Transport and Tourism, rather than the respondent's residence address. The network distance from the representative point of the respondent's residence to the nearest elementary school was calculated using ArcGIS ver. 10.3.1 (Esri, Redlands, CA, USA) [32]. The network distances were categorized into four groups for every 400 m (<400, 400-799, 800-1199, and ≥1200 m). The 400-m category was determined on the basis of prior literature and guidelines on the proximity to the destinations [33][34][35]. Walking distance within five minutes of walking time was often represented by a radius measuring 400 m among urban planners [36]. The neighborhood concept proposed by Clarence Stein also suggests that elementary schools should be located at the center of neighborhood units within a 400-m walking distance of all residents [37].

Statistical Analysis
Descriptive statistics were used to summarize the participants' characteristics, their number, and the sex-stratified percentage of subjects for each variable. Chi-square tests were used to report sex-related differences for each variable. Logistic regression analysis was performed to investigate the association between depression and accessibility to the elementary school. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by sex because of the possibility of sex-related differences in descriptive statistics. Stata 16.1/IC (StataCorp, College Station, TX, USA) was used for all statistical analyses. Table 1 shows the sex-stratified results of the descriptive statistics of the 131,871 individuals. The incidence of depression was higher in males than in females (22.9% and 22.3%, respectively, p < 0.001). Among the older adults, 15.2% lived near an elementary school (<400 m), and there were no sex-related differences in the proximity to an elementary school. The percentage of the target population of females (51.9%) was higher than that of males (48.1%). The results of the chi-square test showed that a higher proportion of males had more than 10 years of education (70.5% of male participants and 64.4% of female participants, p < 0.001) and employment (31.4% male participants and 20.1% female participants, p < 0.001). Moreover, men were more likely to be married (84.8% of males and 61.6% of females, p < 0.001) and less likely to live alone (37.9% of males and 48.9% of females, p < 0.001). A higher percentage of male participants drove cars than female participants (76.1% and 40.1%, respectively, p < 0.001). Regarding psychosocial factors, female participants tended to meet with friends more frequently than the male participants (more than once a week: 48.9% and 37.9%, respectively, p < 0.001). The OR and 95% CI for the association between living near an elementary school and depression are shown in Table 2. Among male participants, there was no significant association between distance to the elementary school and the incidence of depression. However, among female participants, compared with the participants who lived less than 400 m away from the nearest elementary school, those who lived 400-799, 800-1199, and >1200 m away were 1.06 (95% CI 1.00-1.12), 1.07 (95% CI 1.00-1.14), and 1.07 (95% CI 1.00-1.15) times, respectively, more likely to have depression. In terms of the association between covariates and depression, the risk of depression was higher for both men and women with lower education and income, no job, unmarried, living alone, not living in an owned house, and no driving habits. Less frequent going out and seeing friends was associated with a higher risk of depression for both men and women, but this trend was more pronounced in women than in men. Considering age group as a covariate, older age was associated with a lower risk of depression for both men and women aged 70 years and older compared to those aged 65-69 years. The risk of depression has been reported to increase with age, although this trend was reversed when educational history, income, employment, and marital status were included as covariates in this analysis [42,47]. Among the associations between covariates and depression, the trend for men and women differed in duration of residence. Men aged 60 years and older were at a higher risk of depression than those who lived for less than 20 years, but there was no association between duration of residence and depression in women.

Discussion
The present study confirmed the association between depression and basic demographic information as reported in previous studies: Frequency of going out and visiting friends, home ownership, length of residence in a community, and population density. For example, a significant association was found between higher education and higher income and lower risk of depression. Being married, having a family, and having a job were also associated with a lower risk of depression. Further, those who went out more frequently and had frequent interactions with friends had a lower risk of depression. Regarding the residential environment, the results suggest that owning a house and having a longer residence duration may be protective factors for the risk of depression in men. Although the association between population density and risk of depression was been consistent, the present study showed an association between higher population density and lower risk of depression [14,48].
The present analysis also suggests that older women who live near an elementary school may have a lower risk of depression than those who do not, even after controlling for basic demographic information such as frequency of going out, frequency of meeting friends, household status, duration of residence, and population density, which are reported to be associated with depression [31][32][33][34][35][36][37][38][39]. The ORs for the association between elementary school proximity and depression were smaller than those of basic demographic information and other data; however, the large number of participants analyzed in this study allowed us to detect the effect. We discuss several mechanisms by which the environment near an elementary school may reduce the risk of depression among older women.

High Social Capital as the Center of the Community in the Elementary School Neighborhood Environment
Social capital may be related to the association between high proximity to an elementary school and low depression. Putnam defined social capital as "features of social organization, such as networks, norms, and social trust that facilitate coordination and cooperation for mutual benefit" [49]. In addition, evidence suggests that areas with higher social capital, that is, more connected people and more cooperative behavior, have lower rates of anxiety, depression, and other psychiatric disorders. A study examining the relationship between public space and sense of community in Australian neighborhoods reported a significant association between distance to the nearest school and sense of community, with greater distance to the nearest school being linked with a lower sense of community [50]. The authors considered that participation in more neighborhood and school activities may contribute to expanding social networks, developing friendships, and a greater sense of community. In contrast, an American study reported no linear association between the distance to a school and social cohesion, which is one index of social capital [51]. The lack of association was assumed to be related to the means of transportation for getting to school. If a school has many students who commute to school by bus or private transportation, there may be fewer opportunities to increase the school's collective effects. In other words, students are more likely to walk to school in their neighborhood up to a certain threshold distance, and there is a positive relationship between social cohesion and school proximity up to that threshold. However, the relationship between social cohesion and school proximity may disappear farther away from that threshold [51]. Thus, we can speculate that the association between elementary school proximity and social capital is related to whether the school is within walking distance. More than 90% of Japanese elementary school students walk to school [52]. This study found a higher odds ratio for depression among female older adults living at a distance of more than 400 m from an elementary school, which roughly supports the findings of previous studies.
Moreover, the Ministry of Health, Labour and Welfare suggests that elementary schools can be a base for social capital because they are a venue for student activities and a place for interaction between parents and community members. Moreover, it cites the fact that the activities of community organizations are often organized within the elementary school district as a possible reason for the above factors [53]. A questionnaire survey of Japanese adults older than 65 years reported that women were less likely to go out, work, and engage in hobby activities than men. However, in contrast, women were more likely to participate in neighborhood and community association activities [54]. Given that participation in elementary school-based activities of community organizations is relevant in the mechanism by which high elementary school proximity contributes to improved social capital, sex-related differences in community activity participation may explain the association, especially for women.

The Safety of the Elementary School Neighborhood Environment
The second factor regarding high proximity to elementary schools that was associated with lower depression among older adults can be assumed to be the high safety level in the environment near elementary schools. The Cabinet Office in Japan promotes traffic safety on school routes through the cooperation of residents, schools, boards of education, municipalities, and the police, which includes community-based supervision, police patrols, and traffic restrictions [55]. In Japan, school zones are designated as critical areas for traffic safety policies to protect children from traffic accidents and are located within a 500-m radius of an elementary school on the school route. The school zone imposes various traffic restrictions, such as installing new crosswalks and curb mirrors, sidewalk widening, one-way traffic and speed restrictions, and a ban on traffic during school hours [56]. These strategies have contributed to traffic-related safety in the elementary school neighborhood environment.
Perceived neighborhood traffic-related safety was negatively related to possible depression in older adults [57,58]. Furthermore, neighborhood risk perceptions are reported to be higher in women than in men [59]. Thus, women may be more sensitive and stressed about low traffic safety in their neighborhoods. The results of this study match those of earlier studies about the high incidence of depression in women living at a greater distance from elementary schools.

Potential for Contact and Intergenerational Interaction with Children in an Elementary School Neighborhood Environment
A third factor that may contribute to less depression as elementary school proximity increases is that more frequent contact with children in the elementary school neighborhood environment may foster generativity. Erikson defined the concept of generativity as an interest in contributing to the well-being of others, especially the younger generation, and as a developmental challenge in middle age and later years [60,61]. Childbearing, parenting, and social interactions possibly foster generativity by increasing interest in the younger generation's development and well-being [60,62,63]. Furthermore, higher levels of generational interest and more frequent generational interactions, that is, greater generativity are associated with better mental health in old age [62][63][64][65]. According to the findings of a US study, intergenerational exchange was associated with improved subjective health status and psychological well-being [66]. In another study of older Japanese adults, positive intergenerational interaction was suggested to foster generativity and improve well-being in older age [61]. Previous research reported that generativity tends to be higher in women than in men [67]. Another study has shown that generativity impacts subjective well-being, with the trend being more robust in women than in men [62]. The results of this study are consistent with previous research findings, which showed that women tend to have greater generativity and better well-being.

Strengths and Limitations
The strength of this study is that it is one of the few studies that investigated the relationship between elementary school proximity and depression among older adults in a large epidemiological dataset covering both urban and rural areas. Understanding the relationship between depression in older adults and their neighborhood environment is essential for supporting community-dwelling older adults. Clarifying the health risk-preventing effects of elementary school neighborhoods, which exist in tens of thousands of locations nationwide, may have implications for city design, such as developing senior living centers near elementary schools.
Another strength of this analysis is that it uses objective data as an explanatory variable. Subjective indicators using questionnaires have often been used to analyze environmental factors; however, it has been noted that there are individual differences in the perception of subjectively measured environmental factors. The use of objective data as an indicator facilitates objective assessment and comparison of regional differences.
Nonetheless, this study has the following limitations. First, the cross-sectional design precludes the identification of a causal relationship. The second limitation is that respondents who needed long-term care and were not independent in their activities of daily living (ADLs) were excluded from this analysis. The results are only for community-dwelling older adults who can live independently before being certified for long-term care. The third limitation is that some of the residential data used in the analysis may differ from the actual address. For privacy reasons, the participant's residence point data were substituted with the latitude and longitude of the representative points of the block-level location reference information provided by the Ministry of Land, Infrastructure, and Transport. Therefore, the network distance to the nearest elementary school, which is the explanatory variable in this study, differs from the actual distance from the point of residence. However, since the average radius at the block was 258.7 m, few respondents were expected to move across this explanatory variable's 400-m category. Finally, we cannot precisely discern how elementary school proximity affects depression among older female respondents because our results did not specifically identify the factors in the elementary school neighborhood environment that prevent depression among older women. It is unknown whether it is the elementary school environment's safety and walkability or influence by direct or indirect contact with children that contributes to the abovementioned effect. A more detailed analysis is needed in the future, as clarification of the mechanisms will allow more effective and specific interventions to be implemented.
Despite the limitations described above, this study presents findings that can help create a community that prevents depression among older adults.

Conclusions
This study suggests that proximity to an elementary school may be a protective factor for the mental health of community-dwelling older women living independently in the community, confirming part of our hypothesis. It may encourage participation in community activities based on the elementary school and promotes interaction with children, as promoted by the age-friendly cities guide [20]. In the future, clarifying the mechanism of the protective effect of elementary school proximity on depression among older women may help examine specific interventions to prevent depression. Furthermore, examining the mechanisms underlying the gender differences in this study may help develop effective approaches for both men and women. The above research to elucidate such mechanisms could contribute to a design guide for age-friendly cities. Informed Consent Statement: Potential participants received written information on the purpose and significance of the JAGES study; the burden, expected risks, and possible benefits of study participation; voluntary consent and withdrawal of consent; and handling of personal information and privacy protection, and that the submission of the completed survey form would be regarded as their consent for study participation.
Data Availability Statement: Data is not suitable for public deposition due to ethical concerns. Data are from the JAGES study. Requests for data may be sent to the data management committee: dataadmin@jages.net.


extfieldsofstudy:
Computer Science
Psychology

text:
Evaluation of Factors Affecting Student Participation in Peer-Assisted English Learning Based on Online Education Platform

Through a questionnaire survey, this study explored the factors affecting student participation in peer-assisted English learning (PAEL) based on online education platforms. Specifically, the authors constructed the system of PAEL contents, analyzed the online PAEL behaviors of students, and evaluated the student participation in online PAEL from both surface participation and deep participation. On this basis, the influencing factors of student participation in online PAEL were evaluated thoroughly. In the end, several countermeasures were presented to solve the problems with student participation in online PAEL. The results show that: the online PAEL face such problems like low-level knowledge structure and poor interaction quality, weak intensity of interaction, and inactive atmosphere of collaboration; In general, the students are not actively participating in online PAEL; the student participation in online PAEL is greatly affected by teachers, students, teaching contents, and online education platforms; the low participation in online PAEL mainly arises from the weak motives of students for online PAEL, the inadequate teaching design and supervision of teachers, and the imperfect functions of online education platform. The research enriches the theoretical and practical results on the factors affecting student participation in online PAEL. Keywords—Online education platform, peer-assisted English learning (PAEL), interaction behavior, influencing factors of participation

Introduction
The popularization and application of Internet technology has greatly changed people's learning methods, breaking the limitations of time and space of traditional teaching method, now students can learn according to their own needs anytime and anywhere [1], and online education platforms are providing an excellent environment for teacher-student exchanges [2]. Especially in recent years, colleges and universities have gradually realized the importance of online teaching, and they have established various online education platforms successively.
Student participation is a necessary condition for online learning, the degree of participation directly determines the teaching effect of online learning [3]. Peer-assisted learning is a learning method with the interaction between peers as its core content, in an online learning environment, the quality and features of such interactive behavior between learners have a direct impact on learners' learning efficiency and their enthusiasm to participate in online learning [4]. In view of this matter, scholars at home and abroad have conducted researches on student participation and peer-assisted learning in the context of online learning, and have achieved fruitful results. In terms of online learning participation, scholars have analyzed from the aspects of the concept of student participation in online learning, the online learning participation behavior, the influencing factors of student online learning, and the promotion strategies for online learning participation of college students [5]. In terms of peer-assisted learning, scholars have studied from the aspects of the theories of peer-assisted learning, the patterns and strategies of peer-assisted learning, and the application of peer-assisted learning, etc. [6]. After reviewing related reference literatures, it's found that current research on the influencing factors of student participation in peer-assisted learning based on online learning is insufficient [7]. Therefore, based on the above analysis, this paper attempts to analyze and study the influencing factors of student participation in online PAEL based on online education platforms.

2
Interactive Behavior of Students' Online PAEL Based on Online Education Platforms

Construction of the interactive content system of PAEL
The determination of interactive content of students' online PAEL is the core content for the analysis on the interactive behavior of students' online PAEL [8]. Therefore, from the perspectives of learning community and knowledge construction, this paper constructed the interactive content system of PAEL [9], as shown in Figure 1.

2.2
The interactive behavior analysis of PAEL 145 students from 3 classes of non-English majors in a university were chosen as the research objects to conduct interactive behavior analysis on students' online PAEL. According to the interactive content system of PAEL established above, the contents of online posts generated during students' online PAEL were collected, classified, and converted to analyze students' interactive behavior during online PAEL [10].  1. Overall content analysis Table 1 shows the statistics of the percentages of various types of posts about PAEL topics posted by students on online education platforms. According to statistics, the top 3 were emotional posts, posts for asking questions or starting topics, and posts for answering questions, accounting for 23%, 21% and 14% respectively. Emotional posts are mostly good-hearted emotional output, the post contents are usually evaluations, encouragement, and affirmation given by students to their peers or team leaders for their PAEL; although these posts are not that related to the learning content, they can promote emotional communication and exchanges between peers, and they are helpful for PAEL. Posting for asking questions or starting topics are mostly about the problems encountered by students during English learning, and they post them to seek answers from their peers, such as the rules of English grammar, the differences in sentence patterns, etc., this is the basic stage of the cognitive development of learners and the foundation of students' PAEL in subsequent stage. Compared with the posts of raising questions and initiating topics, the number of posts answering questions is much less, only accounting for 14%, indicating that students' PAEL is in a poor mutual beneficial status, during interactive activities, most students are in a "receiving" status without "output". According to the statistics, the bottom 4 were learning reflection posts (3%), information sharing posts (5%), agreements or doubts (7%), and opinion summary (7%), indicating that only a small number of students can summarize and reflect on the knowledge they learnt and sublimate the knowledge to another level, most of them lack independent thinking when studying, and they are used to follow the herd. In addition, posts unrelated to learning and topic discussion accounted for 8%, indicating that students' PAEL lacks effective teaching organization and management.

Cognitive and interactive behavior analysis
The learner's cognitive and interactive behaviors have an important impact on their knowledge structure construction. To further explore the interactive behaviors among students during online PAEL and understand the interaction quality of learners, this paper analyzed the conversions between learner behaviors from the cognition and interaction aspect with the largest number of student posts. Table 2 shows the frequency and score statistics of learners' behavior sequences. Rows in the table represent the initial behavior, and the columns represent the subsequent behavior. For example, P2P4 represents that a student performs creation behavior immediately after the demonstration behavior. SPSS was used to convert the behavior frequency to Zscore to obtain the learner behavior scores [11]. According to the table, among the learning behavior sequences, only four reached the significant level, namely P1-P1, P1-P2, P3-P1, and P4-P4, indicating that the students' cognition structures during PAEL were mostly at the first, third, and fourth stages; the learning behavior sequences did not proceed according to the cognitive level from low to high, and this means that the students' overall knowledge structure is at a relatively low level.

Problems in the interactive behavior of students' online PAEL
The above analysis results suggest that there're a few problems with students' online PAEL: first, the low-level knowledge structure and poor interaction quality of learners, specific manifestations are: the dialogue between peers is superficial and of low reciprocity level (less mutually beneficial), the dialog content is random and discrete, and the individual behavior is irregular; second, weak interaction intensity of learners, and inactive atmosphere of collaboration, specific manifestations are: the interaction between students lacks effective replies, and it's in short of effective instructions from teachers and administrators.

Influencing Factors of Student Participation in PAEL Based on Online Education Platform and the Evaluation
Analysis suggests that there are still many problems with students' PAEL based on online education platforms. In order to improve the efficiency of online PAEL, combining with relevant reference literatures, this paper gave an overall evaluation to students' online PAEL from two aspects of surface participation and deep participation [12]. Then by conducting questionnaire survey and interviews, the influencing factors of student participation in PAEL based on online education platforms were further analyzed and evaluated.

Surface participation and evaluation indicators
Surface participation refers to the explicit learning behaviors of students during their online learning process recorded by the management system of online education platforms [13], such as the time spent on watching videos, and the status of homework completion, etc. By analyzing students' online learning data, this paper determined three evaluation indicators for the surface participation of students, namely clickbrowse, create-reply, and complete-submit; under each evaluation indicator, there're several second-level evaluation indicators, as shown in Figure 2. By sorting out the platform data and calculating one by one according to the corresponding standards, the evaluation indicators of both levels were eventually shown in a hundred-mark system.

Deep participation and evaluation indicators
From the two aspects of homework correct rate and post content quality, this paper determined the evaluation indicators for the deep participation of students, then, based on whether an indicator can be directly measured or not, the evaluation indicators were divided into two kinds: direction measurement and indirect measurement, as shown in Figure 3; then, standard reference measurement methods were adopted for the statistical analysis of relevant data [14].

3.3
Overall evaluation of students' participation in online PAEL Figure 4 shows the statistical results of students' participation in online PAEL, it can be seen from the figure that the data exhibit a high degree of dispersion. For the degree of participation of students in online PAEL, the highest score was 88 points, the lowest score was 2 points, the average score was 62 points, and the standard deviation was 14, indicating that the overall situation of student participation in online PAEL was not good.
In order to further figure out the participation status of students in online PAEL, this paper analyzed the current status of students' surface participation and deep participation in PAEL, and the results are shown in Figure 5. According to the figure, we can see that the data of participation degree showed high-degree dispersion and large fluctuations, indicating that the situation of students' surface participation and deep participation was not good.

Statistics of students' participation in PAEL
Still, the 145 students from 3 classes of non-English majors in a university were taken as the research objects. After reviewing relevant domestic and foreign documents, the Questionnaire for Investigating Influencing Factors of Student Participation in Online PAEL [15] was designed. A total of 145 questionnaires were distributed, 132 valid questionnaires were returned, the effective rate was 91.03%. Then the questionnaires were sorted out to analyze the influencing factors of student participation in online PAEL. Figure 6 shows the survey results of students' willingness to participate in online PAEL. The students who are reluctant and very reluctant to participate in online PAEL accounted for 1.6% and 13.7%, respectively. Students who participate in PAEL as required accounted for the highest proportion of 59.4%, which is more than half of the total, indicating that most students do not participate in PAEL out of their own willingness or learning needs, they just complete them as learning tasks per the teachers' requests.  Figure 7 gives respondent students' descriptions of their participation in online PAEL, according to the figure, students who are not involved in or rarely involved in PAEL accounted for 22% of the total number; students who always participate in or often participate in PAEL accounted for 1.5% and 22.2% respectively, indicating that the situation of students' participation in online PAEL is not optimistic. Figure 8 shows the survey results of students' satisfaction with online PAEL, it can be seen from the figure that students who chose "not so satisfied" accounted for 34.4% of the total number, and those who are satisfied and quite satisfied accounted for 37.5% and 20.8%, respectively, indicating that although most students are satisfied with their online PAEL results, still, some students are not that satisfied.  Figure 9 gives the statistics of students' perceptions of the influence of teachers on student participation in online PAEL, we can see from the figure that among the several teacher factors, three factors have greater influence on student participation in PAEL, namely: whether teachers provide guidance and help for PAEL; whether teachers assign online learning tasks; whether teachers guide and encourage online PAEL. As for other teacher factors, the percentages of students who believed these factors also have an impact on PAEL were all above 40%. Therefore, this indicates that the teachers' influence on student participation in online PAEL is non-ignorable.
ii. Student factors Figure 10 gives the statistics of the percentages of students choosing agree with the 6 questions about PAEL participation, the data suggests that more than half of the students agreed that "having positive expectations for online learning tasks" and "the selection and application of learning methods" have great influence on their participation in PAEL; except for the question of "are you interested", as for the other questions, the percentages of students who agreed these factors have an impact on PAEL were all above 45%, indicating that students themselves have a great influence on their participation in online PAEL. iii. Teaching content factors Figure 11 shows the survey results of the influence of teaching content on student participation in online PAEL. Statistical data tells us that the two most influential teaching content factors for student participation in online PAEL are "types of questions for online assignments" and "peer communication and feedback"; except for the two factors of "clear teaching objectives and content" and "online and offline teaching content consistency", for the other factors, the percentages of students who agreed these factors have an impact on PAEL were all above 45%, indicating that the teaching content does have a great impact on student participation in online PAEL.
iv. Online education platform factors Figure 12 shows the survey results of the influence of online education platform on student participation in online PAEL. From the figure we can read that students believe the resource compatibility has the greatest impact, followed by the "interesting and interactive learning resources" and "resource update range and frequency". Except for the factor "time and space convenience of platform use", for the other factors, the percentages of students who agreed these factors have an impact on PAEL were all above 45%, indicating that the online education platforms also have a great impact on student participation in online PAEL. Fig. 11. Influence of teaching content on student participation in online PAEL

3.5
Problems and countermeasures for student participation in online PAEL

Problems
Through the above analysis, we have found three problems with student participation in online PAEL, namely: i. Weak motives of students for online PAEL The English subject has always been a headache for students. The difficult learning content and uselessness are the general reasons for their lack of interest in English learning. Besides, some students feel that online learning is not real enough, they have weak sense of knowledge gaining and the online learning takes up their spare time, therefore, students are interested in online PAEL; moreover, some students rarely take the initiative to conduct online learning since their self-learning ability is weak.
ii. Inadequate teaching design and supervision of teachers The teaching contents prepared by teachers for online education platforms are mostly in the form of text, courseware, or videos; the teaching content is basically the same with the textbooks, there's nothing new nor interesting, therefore they can hardly attract students' attention. Meanwhile, teachers' supervision on students' online PAEL and homework completion is inadequate. Teachers invest few time and energy in students' PAEL and seldom participate in the discussion and exchange of students, and the teachers' feedbacks are always delayed, all these are reasons for students' low participation in online PEAL [16].
iii. Imperfect functions of online education platforms Online education platforms are the main front for students to conduct PAEL, however, in the design of online education platforms, some functions are flawed, causing inconvenience for operations, such as the poor compatibility of platform resources, some content cannot be viewed on mobile phones and it has certain adverse influence on students' online PAEL; in addition, there're few extended content for English teaching and learning on the online education platforms, the contents on these platforms are mostly the contents of textbooks, teaching materials, and courses, which is not attractive to students and is not conducive to students' extended learning.

Countermeasures
Based on the survey results and data analysis of students' online PAEL situations, this paper proposed following suggestions and countermeasures for improving students' participation in online PAEL [17]: Students are the subjects of online PAEL activities; therefore, they must be fully aware that they are the dominant party in learning, they should improve their selflearning ability and self-management ability, make full use of the resources of online education platforms, conduct autonomous online learning, and use the platforms to interact with their peers, thereby forming a good learning atmosphere for mutual assistance.
ii. Teachers First, teachers should carefully design the teaching content, provide comprehensive, rich and diverse teaching resources for students' online PAEL, reasonably arrange and design the teaching tasks, and stimulate students' interest in PAEL; second, teachers should formulate proper assessment standards for students' PAEL, strengthen supervision and assessment on students' online PAEL, urging students to perform online PAEL through supervision and assessment and cultivate good online PAEL habits; third, teachers should actively participate in students' online PAEL, offer technical supports, participate in the question discussion of students, and promote teacher-student and student-student PAEL.
iii. Online education platforms When designing and upgrading online education platforms, platform designers and administrators should take the teachers' and students' PAEL requirements as the starting point, constantly improve the various functions of the platforms, create more real scenes for the knowledge and skill transfer of students, supply rich extended resources for teaching, set more interactive activities, thereby enhancing and enriching students' experience in online PAEL.

Conclusion
Student participation is a necessary condition for online learning. The quality and features of such interactive behavior between learners have a direct impact on learners' learning efficiency and their enthusiasm to participate in online learning. This paper conducted a research on the influencing factors of student participation in online PAEL and obtained the following conclusions: 1. This paper analyzed the interactive behavior of students' online PAEL based on online education platforms and the results showed that there're a few problems with student participation in online PAEL, namely the low-level knowledge structure and poor interaction quality, the weak intensity of interaction, and the inactive atmosphere of collaboration. 2. From the two aspects of surface participation and deep participation, this paper gave an overall evaluation to students' online PAEL and the results showed that overall situation of student participation is not satisfactory, both the surface participation and deep participation of students are not good. 3. The survey results on the influencing factors of student participation in online PAEL showed that teachers, students, teaching contents, and online education platforms all have great influence on student participation; the weak motives of students for online PAEL, the inadequate teaching design and supervision of teachers, and the imperfect functions of online education platform are all causes for the low participation of students in online PAEL; aiming at these problems, the paper proposed a few suggestions and countermeasures.


Study of virtual reality for mild cognitive impairment: A bibliometric analysis using CiteSpace

Objectives Non-invasive and low-cost virtual reality (VR) technology is important for early evaluation and intervention in mild cognitive impairment (MCI). This study aimed to demonstrate the current status of overseas and domestic research as well as the focus and frontier of VR technology among individuals with MCI through a bibliometric analysis. Methods Studies from the core collection of Web of Science™ between 1995 and 2020 were used; furthermore, CiteSpace 5.7 R3 was utilized to analyse information on authors/cited authors, keywords, burst words, and cited references. Results In total, 230 publications were identified. Most studies were published in the USA (45 publications) and Italy (41 publications), where Guiseppe Riva ranks first (14 publications), and Tarnanas I is the author with the highest centrality (0.44). The hot topics in VR applications in the MCI population are ‘physical activity,’ ‘people,’ ‘single-blind,’ ‘disease,’ ‘walking,’ ‘technology,’ ‘working memory,’ and ‘risk’ in recent years. The keyword ‘mild cognitive impairment’ has attracted extensive attention since 2012, showing the strongest citation outbreak (8.28). The clustering results of the literature show the research types and emerging trends, including ‘exergame,’ ‘serious games,’ ‘spatial navigation,’ ‘activities of daily living,’ ‘exercise,’ ‘enriched environment’ and ‘wayfinding.‘ Conclusions Cognitive assessment and nonpharmacological intervention research on patients with MCI have become the focus of dementia prevention in recent years. Virtual technology, combined with traditional methods such as exercise therapy, provides new ideas for innovative cognitive evaluation and cognitive intervention.

Introduction
With the increasing trend of population aging, the number of elderly people with dementia is increasing each year. It is estimated that by 2050, the number of dementia patients in the United States will exceed 13.8 million. These increases will have a marked impact on the healthcare system. Mild cognitive impairment (MCI) is a grey area between normal cognitive aging and dementia. According to the 2018 American Academy of Neurology updated guideline, the incidence rates of MCI were 6.7%, 8.4%, 10.1%, 14.8%, and 25.2% for those aged 60e64, 65e69, 70e74, 75e79, and 80e84 years, respectively [1]. These individuals have a tenfold greater risk of progression to dementia than the normal elderly population [2,3]. Early cognitive management for patients with MCI not only slows or reverses the downward trend from MCI to dementia but also reduces health care expenditure.
Virtual reality (VR) is a computer-generated effect that can simulate a given scene in the real world through three-dimensional (3D) graphics and other sensory experiences (vision, touch, and motion feeling). Users can interact with such virtual environments through special electronic devices [4]. VR application in the cognitive management of MCI patients remains a topic under research. A study developed the virtual supermarket, which had a correct classification rate (CCR) of 87.3% in distinguishing MCI patients from healthy people [5]. Researchers considered that VR might be more ecologically effective than a paper and pencil or computer evaluation because participants can navigate in the virtual scene from a 3D 360 'first-person' perspective [6]. Moreover, the interactivity of VR allows patients to interact with characters/ scenes in the virtual environment through different interactive devices and to obtain timely feedback. For example, VR intervention, based on visual feedback, enables patients to see their actions and to constantly adjust their position in the virtual scene [7,8]. Patient satisfaction surveys show that compared with the traditional paper and pen intervention, VR cognitive intervention is more attractive to older adults [9,10]. Therefore, VR is a promising tool for neuropsychological assessment and cognitive intervention.
Bibliometrics is a common analysis method for evaluating or quantifying research literature and information. CiteSpace software is a web-based Java application developed in 2004 by Professor Chaomei Chen for exploring the trends and patterns in a knowledge domain [11]. CiteSpace involves three core metrics: burst detection, betweenness centrality, and heterogeneous networks. These metrics are useful for describing the nature of a research front, detecting existing scientific schools and academic networks, and identifying emerging research fronts and abrupt changes. One study examined 21,167 worldwide literature about VR from 1970 to 2018, analysing these materials and evaluating VR development trends and future research directions [12]. Studies on VR application in MCI patients have been published worldwide. However, no research has gathered systematic data on this global scientific output yet. Therefore, it is necessary to make sense of the ballooning information in this research field by visualised analysis. Accordingly, we aimed to investigate the current status of overseas and domestic research as well as the focus and frontier of VR technology through a bibliometric analysis among individuals with MCI.

Data collection
This research involved the core collection materials of the Science Citation Database (Web of Science), including SCI-EXPANDED, SSCI, A&HCI, CPCIeS, CPCI-SSH, BKCIeS, BKCI-SSH, ESCI, CCR-EXPANDED, and IC. Advanced retrieval of subject words was adopted. The retrieval formula is as follows: #1 comprised 'virtual reality' OR '3D environment' OR 'immersive virtual reality' OR 'simulated environment', #2 comprised 'mid neurocognitive disorder$' OR 'mild cognitive improvement$' OR 'cognitive improvement$' OR 'cognitive improvement$' OR 'cognitive disability$' OR 'cognitive decision$' OR 'mental differentiation$' OR 'cognition disorder' OR 'cognitive dysfunction,' and for #3, #1, and #2. The first article about the application of VR to the MCI population was published by Pugnetti et al., in 1995. Thus, the time span for the search was from 1995 to 2020 (retrieval date: February 20, 2021). Thus, 394 studies were initially found, including original articles and reviews. After filtering based on the literature exclusion criteria, the dataset was reduced to 230 records, which contained 571 references.

Inclusion criteria
The inclusion criteria were 1) peer-reviewed published original articles on VR application to the MCI population, including basic and clinical research, 2) related reviews, 3) articles published from 1995 to 2021, and 4) English articles.

Exclusion criteria
The exclusion criteria were 1) articles not officially published, 2) conference abstracts and proceedings, corrigendum documents, 3) repeated publications, and 4) unrelated articles.

Analysis tool
In recent years, CiteSpace has grown into the most characteristic and influential information visualisation software. CiteSpace is used for bibliometric analysis through a six-step procedure: time slicing, thresholding, modelling, pruning, merging, and mapping [11]. The visualisation knowledge network created by CiteSpace comprised nodes and links. Difference items, such as authors, countries, institutions, and cited references, are represented by different nodes. The size of each node indicates the count of literature. High centrality nodes using purple trims represent the turning points or pivotal points in one field. The lines between nodes indicate cooperation or co-occurrence or co-citation relationships: the thicker the line, the tighter the connection [13e16].
The parameters of CiteSpace in this study were as follows: time slicing (1990e2020), years per slice (1), term source (all selections), node type (choose one at a time), selection criteria (top 50 objects), and pruning (pathfinder). To understand the frontiers of VR usage among people with mild cognitive impairment and to examine development trends in the latest research, this study analysed coword networks of keywords.

Publication output
The first paper about VR application for cognitive impairment, 'Evaluation and retraining of adults' cognitive impairment: which role for virtual reality technology?', was published in 1995 by Pugnetti et al. [17], which suggests the beginning of VR application in people with cognitive impairment. Since then, publications about VR application in MCI patients have increased persistently. Fig. 1 shows the distribution of volume and time regarding these papers. This research was divided into three stages: the embryonic stage (1995e2005), the slow development stage (2005e2011), and the rapid development stage (2011e2020). During the embryonic stage, few studies examined VR use in MCI patients, with the first article published in 1995. During the slow development stage, publications showed a slow-growth trend, with an average of 20 papers being published yearly. During the rapid development stage, the number of publications increased. The year 2020 saw the largest number of publications on related topics (65 articles in total). The statistics for the types of documents showed 131 original articles (56.91% of the total number of articles), including 98 articles in the past five years (75% of the total number of original articles). Additionally, since 1995, there have been 99 reviews overall, most of which were published in 2019. These results indicate that VR, as an emerging auxiliary technology, is receiving increasing attention, and consequently, more research is being conducted. However, compared with other research areas, research on VR application in people with MCI is still nascent.

Author and co-authorship
Authors play a critical role in promoting scientific development, especially in defining the past, present, and future disciplines in this field [12]. There were 547 nodes and 696 links in the author collinear map generated using CiteSpace. Therefore, 230 documents involving 547 authors in total were generated. Table 1 shows the top ten authors who published articles related to the application of VR among MCI populations. These authors were active professionals in this field. Guiseppe Riva, a professor in the Department of Psychology at the Catholic University of Sacred Heart in Italy, published the highest number of such articles (14 articles). His research direction over the past five years has shifted to tapping the potential of VR technologies for assessing early cognitive function among patients with cognitive impairments such as Alzheimer's disease, MCI, Parkinson's disease, and posttraumatic cognitive impairment. He considers VR as an innovative and promising neuroscience assessment tool [18e20]. In addition, we found that four cooperative groups with five or more cooperating authors. However, the centrality value for such collaborations was 0; this shows that the cooperation relationship between the authors was not close.
An analysis of author co-citations showed that the number of literature citations was directly proportional to the author's contributions to this field's development. An author co-citation map was generated, including 125 nodes and 177 links. Table 2 shows the top ten co-cited authors and the top ten authors in terms of centrality value. They can be regarded as influential authors for VR application research in MCI populations. For example, Tarnanas's recent five-year research focused on applying VR techniques in the early screening of populations with cognitive impairment [21e23]. In a study, he used Virtual Reality Day-Out Task (VR-DOT) environments to assess their predictive value for MCI patients; he concluded that virtual technology, which is a noninvasive and low-cost computer cognitive assessment method, could provide additional predictive information [22]. Regarding the oriented application of VR technology in cognitive assessment, Plancher's research was similar to that of Tarnanas, and he focused more on the correlation between VR technology and episodic memory diagnosis [24,25]. Optale, Coyle, and others applied VR technology in cognitive interventions for MCI patients. Coyle studied the application of VR cognitive training among MCI patients based on a meta-analysis [26]. One of Optale's studies tested the effects of VR cognitive interventions on memory improvement among older adults and concluded that VR cognitive interventions could improve memory function by enhancing hearing stimulation [27].

Co-occurring keywords and burst keywords
A keyword co-occurrence map can reflect the most popular research topic during any given period and burst keywords (keywords that are cited frequently over some time) can forecast future research trends in a given field [14].
A time span from 1995 to 2020 was selected for the analysis, and the top 50 most cited or occurred items from each slice were chosen. A total of 47 co-occurring keywords appeared, reflecting the range of research topics on VR application among MCI patients. An analysis in terms of co-occurrence frequency revealed that the top ten hot keywords were 'virtual reality,' 'Alzheimer's disease,' 'dementia,' 'mild cognitive impairment,' 'older adult,' 'memory,' 'rehabilitation,' 'episodic memory,' 'cognitive impairment,' and 'performance.' (Table 3).
Burst words refer to the keywords, which are cited frequently in a certain period and considered to be indicators of research frontier topics [14]. Fig. 2 shows the top 25 keywords with the strongest citation bursts between 2010 and 2020. The most recent burst keywords were 'physical activity,' 'people,' 'single-blind,' 'disease,' 'walking,' 'technology,' 'working memory,' and 'risk.' The keyword 'mild cognitive impairment,' showing the strongest citation burst (8.28), emerged from 2012.

Co-citation analysis
Analysing the document co-citation facilitated our understanding of the current highly cited literature; accordingly, we obtained more influential views and ideas in this field [12].
A co-citation network were generated through the cluster functionality using CiteSpace results (Fig. 3). Subsequently, 354 unique nodes, 337 links, and seven main clusters were generated with a modularity Q of 0.6711 and a means silhouette of 0.9772. These references are represented as nodes in a co-citation network. Each node is depicted with a series of tree-rings across the time slices. The size of the node indicates the strength of citations the reference received. The connectivity between the nodes of such references represents how often they are cited by similar articles. Silhouette values of homogenous clusters are closer to 1, which means that the clustering result is more persuasive.
Tables 4 and 5 present the top five co-cited references in terms of frequency and centrality for VR application among the MCI  population. Nodes with high co-citation counts and centrality can be considered as essential references in a certain field. When ranked by citation counts, the first two articles focused on the role of virtual technology in the assessment of episodic memory among MCI patients. Weniger et al. were the first to demonstrate that VR technology was feasible to study spatial memory deficits of persons with amnesic MCI (aMCI) [28]. Plancher et al. found the beneficial effect of active encoding on spatial allocentric memory assessments for distinguishing aMCI patients from healthy older adults [25]. Other papers focused on cognitive training using VR. For example, Man et al. [29] and Manera et al. [10] designed two kinds of nonimmersive VR-based memory training programs and investigated their effectiveness among old patients with questionable dementia and MCI. With the increasing application of VR technology in cognitive intervention among MCI patients, Coyle et al. [26] published the first related review in 2014. Based on the evidence reviewed, VR cognitive training was beneficial to the cognitive domain of attention, working memory, executive function, and so on. When ranked by centrality, the first paper was published by Manera in 2015. The research team developed a serious game (SG), named 'Kitchen and cooking,' and found this virtual game playing a dual role in cognitive assessment and training for MCI populations [30]. Additionally, the virtual scene of a supermarket was the most widely used in cognitive management among MCI populations [5,31e33]. Tarnanas et al. [22] used a VR-DOT environment to evaluate its predictive value in MCI patients. The results of VR evaluation were compared with magnetic resonance imaging, event-related potential, and neuropsychological tests, and VR-DOT performance strongly correlated with existing predictive biomarkers.
The clustering results of the literature show the research types and emerging trends in some knowledge fields. As shown in Fig. 3, the network was divided into seven co-citation clusters: #0 exergame, #1 serious games, #2 spatial navigation, #3 activities of daily living, #4 exercise, #5 enriched environment, and #6 wayfinding. 'exercise' is the largest cluster (#0) consisting 195 nodes. Alves et al.
[34] published a paper named 'Cognitive stimulation for Portuguese older adults with cognitive impairment: a randomized controlled trial of efficacy, comparative duration, feasibility, and experiential relevance,' which has been impacting many authors. The second-largest cluster (#1), 'serious game,' has 30 member articles and an average publication year of 2012. The most active citer in this cluster is Tarnanas et al. [35] in 'Ecological validity of virtual reality daily living activities screening for early dementia: Longitudinal study,' focusing on establishing ecological validity and initial construct validity of a VR-based serious game as a screening tool for early dementia. In the third-largest cluster (#2), the most active citer is Cushman LA. et al. [36] in 'Detecting combined with navigational deficits in cognitive aging and Alzheimer disease using virtual reality,' comparing the performance of self-orientation and scene localization tests among older people with different degrees of cognitive impairment in the real world and the virtual world for the first time and found similar profiles of impairment in realworld and virtual testing.

Interpretation of the results
VR application among MCI patients has become a subject of growing study and an increasingly important area of research. In this study, CiteSpace, a bibliometrics software, was used for author and co-authorship analysis, co-occurring and burst keywords, and co-citation analysis to identify the research focuses and reveal the trends in the past 25 year on VR technology applications among MCI patients.
Bibliometric analysis in our study showed that the application and promotion of VR usage among MCI populations technology are closely related to the development of VR technology.
As early as the 1990s, virtual reality technology had entered the stage of theoretical improvement and application [37]. In 1994, Japanese game companies SEGA and Nintendo launched Sega VR-1 and Virtual Boy, respectively, for the game industry [38]. However, due to the high cost and low resolution of VR equipment at this time, it has not been widely used in the field of cognitive medicine, but some scholars had proposed to apply virtual technology to the field of cognitive evaluation [17]. In 2012, the advent of Oculus Rift ushered in a new wave of development of VR technology [39]. Low costs made VR a big step closer to the public's vision, and also greatly increased the application research of VR technology in people with mild cognitive impairment. However, compared with other fields, the application research of VR among MCI populations is still in the preliminary stage, and there is great potential in this field in the future. The visual analysis of authors and co-citation authors can not only help researchers accurately locate the most popular scholars in this research field, but also reflect the research direction concerned by scholars at home and abroad. In the application research field of VR among MCI populations, the contents of research by the authors with the largest number of papers and the top 10 co-cited authors can be divided into two categories: cognitive assessment and cognitive training. The results of the keyword co-occurrence analysis further confirmed this conclusion. We found that virtual technology has been mainly used in episodic memory training/ assessment, cognitive rehabilitation, and navigation training for people with MCI in the past 25 years. Virtual technology has unique advantages in cognitive assessment and cognitive rehabilitation training in the MCI population. First, several studies have shown that VR technology can simulate daily life scenes to enable patients to reproduce their real cognitive performance in a virtual environment [40,41], which makes cognitive assessment and cognitive training more ecologically effective. In other words, VR-based cognitive assessment can better reflect the real cognitive status of patients [5,42] and VR-based cognitive interventions can transform the training effect to real life [30]. Second, the convenience of virtual technology makes cognitive assessment and intervention break through the constraints of time and space and effectively reduce medical costs and care burden [43,44]. However, at present, researchers still have different views on the acceptance of virtual technology among older adults. Some researchers found that older adults are more interested in VR, whereas others pointed out that older adults have a low acceptance of the new technology because of simulator sickness, reduced vision, and other sensory problems. There are certain security risks as virtual technology use leads to simulator diseases [45]. Therefore, in recent years, 'technology' and 'risk' have become the burst keywords. In the future, more research is needed on how to develop VR technology that is truly suitable for older adults.
As discussed, VR makes it possible to examine and exercise brain activity during dynamic, complex, and realistic situations. In applied domains of prevention and treatment of MCI patients, VR methods continue to accumulate more clinical evidence. This trend should continue as these methods become widely used and are extended to patients with varying degrees of cognitive impairment and broader therapeutic research. The future of VR in MCI is strongly tied to developments in information technology that help to immerse the user in the immersive virtual environment. However, technology is a double-sided mirror. In future research, we should pay more attention to the characteristics of the elderly and

Limitation
Our study has one limitation. We only selected a database, Web of Science, to conduct a comprehensive citation analysis, thus inevitably losing part of the information. In previous studies [13e15], Web of Science was the main literature source of Cite-Space, covering most of the leading research information, which maximised the potential of CiteSpace. Noteworthily, previous studies of VR usage among MCI populations were often based on qualitative analyses of numerous studies in literature, suggesting subjectivity regarding literature selection, classification criteria, hot spot tracking, and direction control. This study quantified the retrieved documents in the form of a visual network, thus increasing the objectivity of the results and providing valuable information on VR and MCI, especially the choice of research direction, cooperation agencies, and references.

Conclusions
Our research mainly analysed the number of publications and trends in the changes of virtual technology in patients with MCI through metrological methods based on CiteSpace, aiming to provide evidence of VR development for researchers, policymakers, and leaders. Firstly, the analysis of author and co-authorship identified that Guiseppe Riva ranked first and Tarnanas I was the author with the highest centrality. Secondly, the analysis of keywords identified 'physical activity,' 'people,' 'single-blind,' 'disease,' 'walking,' 'technology,' 'working memory,' and 'risk,' suggesting that they are hot topics of research in recent years. Last, we found the most influential references through co-citation analysis. These research results may assist future researchers to better comprehend the current situation and future direction in this field.

Data availability statement
We declare the absence of shared data in the present study.

Declaration of competing interest
We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, 'Study of Virtual Reality for Mild Cognitive Impairment: A Bibliometric Analysis Using CiteSpace'.


Literacy Skills as an Effort to Maintain Quality Culture in Mu- hammadiyah Elementary Schools in Malang City During the Covid-19 Pandemic

This research has been conducted based on the declining condition of literacy in Indonesia since 2017. Since quality culture is crucial during this time, a research on literacy skills in elementary schools needs to be done. This is a qualitative descriptive research. It aims to analyze the literacy skills in maintaining the quality culture in Muhammadiyah elementary schools in Malang City during the Covid-19 pandemic. Moreover, the instruments used in this research are interviews and documentation. The research subjects comprise teachers, headmasters, and students of Muhammadiyah elementary schools in Malang City. The results show that during the pandemic, the subjects have applied digital and informational literacy skills in the learning process through several platforms. Moreover, using these skills, the teachers have co-written a compilation of best practic-es registered on ISBN. Supporting factors in literacy skills as a quality culture in Muhammadiyah elementary schools include the intensity to access more information, optimization of teacher skills through various workshops and peer tutors, and improvement of existing infrastructure in schools. While the hindering factor is the understanding of educators and education on the school literacy movement is school literacy.

INTRODUCTION
The unpredicted Covid-19 pandemic originated from Wuhan, China (Ding et al., 2020;Zhou et al., 2020) has changed the lives of people in various sectors around the world (Khasanah et al., 2020). In Indonesia, the cases of people who contracted the Coronavirus are increasing day by day (Setiawan, 2020). According to the data updated by the government, in July 2020, there are 78.572 cases. 3.710 people are dead and 37.636 are cured. This increasing case can threaten the education sector (Zaharah et al., 2020). One of the efforts done by the Ministry of Education and Culture of the Republic of Indonesia to mitigate the spread of Covid-19 is temporarily closing the educational institutions on all levels.
Competence is the ability that a person has to carry out his profession well. The recent year"s PISA results have become an early reminder to change the educational paradigm in Indonesia. According to the research by the National Library of the Republic of Indonesia in 2017, the people"s level of reading interest is 36.48% (low). This result is in line with what was stated by Wandasari (2017) who shows that according to an Indonesian author Ajip Rosidi, in a year, Indonesian children only read 17 pages of a book and take 15 days to finish a page. Moreover, an Indonesian poet and senior author Taufik Ismail states that since the country gained its independence, no school has a single mandatory literary book. This tragedy is known as "Nol Buku Indonesia (Zero Indonesian Book)" (Tim Warta, 2016).
The results of the literacy activity index in Indonesia in 2019 show that out of 34 provinces, East Java ranked 26 (Rahman & Kosasih, 2019). The literacy level of the province is 33.19% (low). Malang City is known as the City of Education (Kadir, 2009;Situmorang et al., 2019;Wirawan, 2015) due to a large number of schools and colleges. There are more than 80 colleges in Malang (Y. I. Permatasari, 2019;Pisdon, 2018). Meanwhile, there are 195 public elementary schools, and 87 private elementary schools spread over five districts (Candrawati & Widiani, 2015). Specifically, in Malang City, there are six Muhammadiyah elementary schools, namely SDM (Sekolah Dasar Muhammadiyah) 1, SDM 3 Assalam, SDM 4, SDM 5, SDM 8 K.H. Mas Mansur, and SDM 9 Panglima Sudirman. SDM 8 K.H. Mas Mansur and SDM 5 have parallel classes. Based on the interview from teachers and hadmasters, the human resources in the school are 40% fresh graduates. The literacy activities have been applied in the schools. Various innovations have been designed to maintain and improve the quality culture of the schools, an example is participating in various literacy workshops. In quality culture, learning, and instruction activities closely related to literacy (Hunt & Birks, 2004;Kurbanoglu, 2003;Olsson & Edman-Staalbrant, 2008). With all limitations and obstructions in the learning process, the schools strive to improve the literacy level through online learning.
Based on the data, literacy is important to be studied as one of the quality culture programs. As a manifestation of quality culture in schools, the Ministry of Education and Culture through the Directorate of Elementary School Development has organized various programs to improve quality learning, such as facilities improvement, school management, character building improvement, school literacy movement, healthy school program, and library performance optimization (Jannah, 2010;Untari, 2017;Widodo, 2018;Zahroh, 2014). Regarding the literacy movement, the Ministry of Education and Culture has stipulated the Decree of the Minister Number 23/2015 on Character Building (Rahayu, 2016) comprising the habituation of literacy culture. This decree has generated the GLS (School Literacy Movement) and became the government"s program (Akbar, 2017;Pradana, 2017) in creating a literate environment in schools (Hidayat & Basuki, 2018;Naibaho, 2007).
This movement is the right momentum to maintain the quality of education. Through this education, literacy can be maintained. The education sector as one of the fields responsible to prepare excellent human resources always gets special attention. Maintaining the quality of education during the Covid-19 pandemic becomes a real challenge (Azzahra, 2020;Pujilestari, 2020). The policy regarding the learning process also has changed. Nowadays, all learning activities are conducted online from home (Liguori & Winkler, 2020; Pena & Lim, 2020). This government"s instruction to maintain physical and social distancing (Masrul et al., 2020;Nurhalimah, 2020;Paramitha, 2020) should be obeyed and thus, the learning process is conducted online (Hiltz & Turoff, 2005).
Direct learning with face-to-face interaction is now limited and even negated (Purwanto et al., 2020). With all the limitations, the education sector suddenly applies the online system. Despite the pros and cons, school residents should adjust to online learning activities. The activities must be designed well to maintain the quality of national education.
Learning and instruction activities are part of a quality culture that can be maintained by every educational institution. The concept of quality culture is a factor in educating people to be noble, honest, responsible, optimistic, brave, skillful, cooperative, resilient, discipline, and having integrity. An important, yet either often missing in Indonesia for literacy is that literacy is primarily a language process.
A school with an excellent quality culture can be identified through several variables, such as school management, learning process, curricular activities, library performance, and health service (Basri, 2011;Puspitasari, 2018). However, the development of quality culture in school requires the participation of all the school residents and the stakeholders, including the parents. Therefore, managerially, the school"s headmaster is responsible for the development of quality culture. Operationally, all school residents and stakeholders are responsible for the school"s daily activities.
This research aims to analyze the implementation of literacy to maintain the quality culture of Muhammadiyah elementary schools in Malang City and to describe the obstacle factor in implementing the literacy to maintain the quality culture of Muhammadiyah elementary schools in Malang City during the pandemic of Covid-19. This research found the implementation of literacy in quality culture in Muhammadiyah elementary schools in Malang

METHODS
The type of qualitative research used is descriptive research. Descriptive research aims to describe the situation of an activity or event. This is in accordance with (Sukmadinata, n.d.) that descriptive research is the most basic form of research to describe the existing phenomena, both the natural phenomena and man-made engineering. This study used descriptive qualitative research to describe the implementation of literacy to maintain the quality culture and its obstacle factor in Muhammadiyah elementary schools in Malang City.
This research was conducted in SD Muhammadiyah 8 K.H. Mas Mansur and SD Muhammadiyah 5 in Malang City in the academic year 2019/2020. The two schools are the members of K3S (the Headmasters Work Group). The subjects are the headmasters, teachers, and students. The data sources comprise words, observation, and interview from the informants, and supporting documents regarding the implementation of literacy as an effort to maintain the quality culture in the elementary schools.
Similar to the other qualitative descriptive studies, the data collection in this study used a minimally to moderately-structured open-ended interviews. The interview process was done through an online platform and filled in a prepared form. During the data collection, a data validity check was required. The data validation in this research used the source"s triangulation. After collected, the data were analyzed. Below is the instrument used in the research. The data analysis method used by the researcher is the Miles and Huberman model started from data reduction, data description, and conclusion (Miles & Huberman, 2007b, 2007a

RESULTS AND DISCUSSION
During the Covid-19, all activities in the society are restricted, including the education sector. Nowadays, all education levels engage in "study at home". Base don the documentation study, the study-at-home policy was implemented on March 9, 2020, after the Ministry of Education and Culture issued the Decree Number 2 and 3 Year 2020 on Online Learning and Work-From-Home to Prevent the Spread of Covid-19. During this pandemic, all activities including learning are conducted at home (Almanthari et al., 2020;Kong, 2020;Moszkowicz et al., 2020).
Despite the emergency, the quality culture of the school should be maintained. Based on the interview results, the quality culture during the pandemic can be maintained through the school literacy movement. This program can be conducted both offline and online. As private schools, both of the schools face a great challenge to maintain their existence in education. One of the efforts is maintaining the quality culture (Ehlers, 2009;Harvey & Stensaker, 2008;Strydom et al., 2004;Yorke, 2000).
The implementation of the quality culture in SD Muhammadiyah 8 K.H. Mas Mansur and SD Muhammadiyah 5 requires time, process, and tenaciousness. All the steps are taken structurally. Based on the interview results, both of the schools have implemented literacy. All the literacy activities were coordinated by a coordinator. Various types of literacy have helped the students to obtain knowledge independently (Latip, 2020;A. Permatasari, 2015;Pratiwi et al., n.d.) The observations are made through observing literacy activities carried out by Muhammadiyah elementary school teachers. Based on the observation results, the learning and instruction activities in both of the schools are conducted online. During the Covid-19 pandemic, learning changed. All face-toface learning activities are now conducted online (Liguori & Winkler, 2020). Recently, almost all the educational institutions in Indonesia conduct digitalbased learning. Even though easy access to information becomes a supporting factor in learning activities, the implementation requires guidelines and supervision.
To maintain the quality culture, the stakeholders should cooperate in succeeding in the program. The stakeholders comprise the headmaster as the policymaker, coordinator as activity commander, classroom teachers as the facilitator of learning activity, and parents/guardian as students' supervisor at home. Based on the interview results, in literacy activities, students are allowed to choose any book they want. However, teachers and parents do not recommend any book that is not in accordance with the students' abilities.
The literacy planning by the schools centralized on the policy made by each of the headmasters, through literacy coordinators, and classroom teachers. The following figure is a structure of roles in the literacy activities of the schools.
One of the activities is reading storybooks at home. Based on the interview results, the students also looked for information and insight on the internet under the supervision of their parents and the guidelines by their classroom teachers. The activities will be evaluated after submitting the tasks to their teachers online. This evaluation is used after each lesson. It takes various forms, the teacher asks the child to retell the reading that has been read. The form of evaluation carried out is also equipped with a rubric.
Various types of literacy are not directly accessed by students at home. The students and teachers are demanded to use technology wisely to support the quality culture of the schools. The benefit that can be gained during this pandemic is an increasing level of literacy. The use of digital literacy keeps developing. The following is one of the forms of literacy done by the students with teachers' guidelines and under parental control.

Figure 1. Teacher"s Instruction in Implementing Literacy
The Figure 1 shows that literacy is designed in form of learning. The learning design is essential to help the students accomplish the learning objectives. As anticipation, the Ministry of Education and Culture has developed a learning program on TVRI channel to be accessed by all students and teachers in Indonesia.
Digital literacy done by students, teachers, and parents during the pandemic has assisted the users to share information (Martin & Grudziecki, 2006). The recent learning process applies to the flexible learning process (Huang et al., 2020). The two schools use it to maintain the existence of quality culture. The characteristics of the learning are 1) the learning process can be done everywhere and anywhere. This is based on the documentation results showing that literacy activity and learning activity can be done every time; 2) the students can learn everything they want; 3) the learning source can be accessed from anywhere; 4) the teachers can innovate in determining the implementation of learning; 5) the implementation can be done flexibly. In the literacy activity, support from the management party becomes the success of elearning (Agustina et al., 2016).
From the teachers' perspective, they can implement literacy by developing the learning materials. The materials are sent to the parents through the provided platform. The parents of both schools use the WhatsApp group chat to communicate. Moreover, as professional development during the pandemic, the teachers keep implementing literacy. The teachers' professional development comprises the practice of science, technology, and skills to improve the quality of the learning process and professionalism of the educators.
The professional development activities are 1) composing scientific works in the educational field; 2) inventing educational technology; 3) designing learning equipment/props/guidance tools' 4) composing scientific writings and participating in curriculum development activities. Based on the interview results during the pandemic, the teachers strove to discuss with each other to compose the best-practice articles. The compilation of the articles is now registered on the ISBN 978-623-7446-13-2 entitled Bakti dari Hati, Senarai Karya Guru, SD Muhammadiyah Kota Malang. The work shows that the teachers still develop information literacy regarding their experiences at school.
Supporting factors in literacy skills as a quality culture in Muhammadiyah elementary schools include the intensity to access more information, optimization of teacher skills through various workshops and peer tutors, and improvement of existing infrastructure in schools. While the hindering factor is the understanding of educators and education on the school literacy movement is school literacy.

CONCLUSION
Due to the decreasing level of literacy in Indonesia, the Minister of Education and Culture formed the School Literacy Movement. The literacy forms implemented in Muhammadiyah elementary schools in Malang City are information literacy and digital literacy. during the pandemic, all learning activities are conducted online. The quality culture of the schools should be maintained. Therefore, the two schools have maximized online learning activity through information literacy and digital literacy. In the implementation, the teachers designed the activities and communicated to the parents. Then, under the supervision of the parents, the students conducted literacy activity through online learning. Supporting factors in literacy skills as a quality culture in Muhammadiyah elementary schools include the intensity to access more information, optimization of teacher skills through various workshops and peer tutors, and improvement of existing infrastructure in schools. While the hindering factor is the understanding of educators and education on the school literacy movement is school literacy. Moreover, to maintain the quality culture, the teachers also implemented information literacy. from the activity, the teachers have composed scientific work in form of book registered on ISBN.
Assalamualaikum Wr. Wb. Good morning, children and mothers at home.
The following is an online home study assignment for grade 3 A / B / C students.
Please cooperate to assist students in completing assignments.
Tuesday, April 14, 2020 Duty: 1. Join a study program at TVRI at 08.30-09.00 a.m. The material is the operation of counting whole numbers and answering the 3 questions. The results of student work are photographed and sent to the class teacher. No later than 09.00 pm.

Mathematics
Please access the link below.
https: // formgle / V1jbggRKK3XvXYeA7 The password Bismillah Material about circumference and irregular shape area.