Introduction
The number of patients with dementia (PwDs) has increased with the aging of the world's population (Alzheimer's Disease International, 2022). PwDs are mostly older adults who are prone to acute illnesses and conditions such as respiratory infections, pneumonia, urinary tract infections, and falling (Benner et al., 2016; Givens et al., 2012; Sampson et al., 2009). The annual hospitalization rate of PwDs is twice that of patients without dementia (Alzheimer's Association, 2017). The behavioral and psychological symptoms of dementia (BPSDs) experienced by PwDs are exacerbated by machine noise, unfamiliar environments, and other environmental disturbances occurring in hospitals (Houghton et al., 2016; Reilly & Houghton, 2019). BPSDs may increase the prevalence likelihood of falls, delirium, malnutrition, aggression, and even death (Featherstone et al., 2019; Fitzpatrick, 2018; Moyle et al., 2011). Avelino-Silva et al. (2017) found that the mortality rate of PwDs in hospitals was higher than that of other patients.
Family caregivers (FCGs) of hospitalized PwDs provide a sense of security and emotional support to the patient as well as act as advocates to ensure their special needs are met (Burgstaller et al., 2018; Clissett et al., 2013; Reilly & Houghton, 2019). Because PwDs are unable to express themselves clearly, FCGs help them articulate their wishes, preferences, and needs, thus preventing their input from being overlooked or ignored and enabling them to participate in medical decisions that may impact them (Reilly & Houghton, 2019). Furthermore, cooperating with FCGs not only allows healthcare professionals to more fully understand the demands and problems of PwDs but also is a key feature of person-centered care provided in hospitals (Burgstaller et al., 2018; Moyle et al., 2011). Therefore, understanding the difficulties faced by FCGs and the strategies they use while caring for PwDs in acute care settings is a prerequisite for healthcare professionals to be able to provide adequate quality of care to PwDs and their FCGs.
One qualitative systematic review was identified on the topic of the difficulties faced by FCGs while caring for relatives with dementia at home. This review, involving 58 qualitative research articles, found FCGs faced difficulties in coping effectively with BPSDs and often felt burdened and stressed (Braun et al., 2019). In addition, Burgstaller et al.'s (2018) meta-ethnographic synthesis of qualitative studies examining the experiences and needs of relatives of PwDs in hospitals found that most of these relatives had negative experiences, including being physically and emotionally exhausted, being excluded from medical decision making, receiving little information about the patients in their charge, and seeing patients not being given person-centered care. This review also identified a number of factors that put FCGs in a more positive frame of mind when dealing with healthcare professionals, including getting expertise, personalized interactions, effective communication, and a good discharge plan (Burgstaller et al., 2018). Furthermore, Beardon et al.'s (2018) systematic analysis of the perspective of informal caregivers on care delivery identified several factors related to the quality of care provided to PwDs. These included how well trained the nurses are, whether person-centered care is provided to the patient, the extent to which FCG is involved in the care plan, and whether the hospital offers a friendly environment.
Whereas the first review focused on the conditions regarding caring for PwDs at home, the other two focused mainly on the experience of FCGs accompanying PwDs in hospitals. None of these studies alone provides a complete picture of the difficulties faced by FCGs while caring for their relatives with dementia, nor do they address questions of how FCGs deal with the problems they encounter. Moreover, there is a lack in the existing literature of culturally appropriate data that may be used to help healthcare professionals in East Asian countries plan future care strategies for FCGs accompanying PwDs in the hospital. Therefore, the purpose of this study was to identify the difficulties faced by FCGs and the strategies they employ while engaged in providing care to PwDs in acute care wards.
Methods
Design
An exploratory design with content analysis and qualitative data collection were used to gain a deeper understanding of the context-related difficulties faced by FCGs and their related response strategies (Leininger & McFarland, 2002).
Context of the Researcher
One researcher who conducted the interviews and data analysis was experienced in conducting research in the realm of providing care for PwDs, had 3 years of experience in care work, and was a certified nurse working in dementia care. In addition, she is a doctoral student and had received trained in qualitative research methods.
Participants and Setting
Purposive sampling was used to recruit participants. People were invited to participate in the study if they were relatives of a PwD, had been serving as the PwD's primary caregiver for at least 6 months, and had borne full responsibility for their care. The data were collected in two acute care wards (neurological and geriatric) at a hospital in southern Taiwan.
Nine FCGs completed the interviews. The participants included seven women and two men who ranged in age from 39 to 78 years. The assessment of the severity of the symptoms of dementia manifested by the PwDs in their charge was carried out using the Clinical Dementia Rating scale, with scores ranging from 1 to 3. The demographic characteristics of the participants are presented on Table 1.
Data Collection
The head nurses of the two wards identified FCGs who met the eligibility criteria for this study and informed the researcher via LINE. The researcher then visited potential participants and scheduled an interview time and place convenient to the interviewee. If desired, the presence of PwDs during the interview was permitted. In this study, only two PwDs participated in the interview. The interviews were conducted based on a semistructured interview guide (Fylan, 2005). Participants were first asked to respond to the principal items: "Please describe any difficulties you have had in caring for your relative during hospitalization" and "Please describe strategies you have used in caring for your relative during hospitalization." Each interview lasted approximately 1 hour. An audio recording was made of each interview. Data were collected from October 2020 to January 2021. According to Patton (2002), qualitative research entails not only transcribing and analyzing audio recordings but also taking notes during interviews and reflecting on the data afterward to clarify the content of interviews. Therefore, the interviewer took field notes on observations and reflections in response to each interview shortly after it was conducted. Finally, recruitment of new participants stopped when data saturation was reached; that is, no additional or new data were found.
Data Analysis
The data were analyzed using a conventional content analysis approach (Graneheim & Lundman, 2004; Hsieh & Shannon, 2005). Analysis began with the researcher briefly reading each transcript from beginning to end once, after which a second, more careful reading was done, with the parts of the transcripts that appeared meaningful marked. After three or four transcripts were open coded, some of the participants' words were jotted down in the margins of the transcripts to highlight keywords and phrases, identifying preliminary codes to which new codes found in the remaining transcripts were then added. All of the transcripts were similarly coded. Finally, some of the identified codes were separated into subthemes and then gathered into categories that reflected the main themes.
Trustworthiness
Lincoln and Guba (1985) proposed four principles to ensure that the collection and analysis of qualitative data are rigorously conducted. To ensure credibility, we aimed to ensure the authenticity of the content of our research data. The interviewer had previous experience in dementia care and had completed a certification program in research training. A participant-centered approach was maintained while the audio recordings and notes were made during each interview. Throughout the data analysis, aspects of the data and the approach to coding were discussed regularly with members of the team, all of whom had experience in qualitative research and dementia care. Two nurse specialists reviewed two of the transcripts and coded them for peer debriefing purposes. The themes were validated by two other FCGs with dementia care experience for member-check purposes. To ensure transferability, we worked to maximize the extent to which the findings of this work are applicable to other circumstances. This study used thick descriptions to guarantee external validity. Because the findings and conclusions were clearly presented, they may be applied to a wider range of caregiver experiences, for example, to FCGs and paid caregivers who care for PwDs in other acute care facilities. In terms of dependability, we assumed that if the steps followed to conduct this study were repeated, similar results would be found. Furthermore, we clearly describe the research methodology and provide the original materials used, for example, the audio recordings and transcripts of the interviews, for verification. After completing the data analysis, the researcher randomly selected one transcript and then reanalyzed and recoded it. The reliability among different raters was found to be 81%. In terms of confirmability, we expected the findings to be generated from original data. During the research process, member checks and reflection journals were used to help the researcher clarify her thinking and elevate the trustworthiness of the research findings.
Ethical Considerations
The hospital institutional review board for ethical consideration approved this study (No. B-ER-108-464). The purpose of the study as well as the risks and benefits of participating were explained to FCGs. The informed, written consent of each participant was obtained before the interview was conducted. Participation was voluntary, and the anonymity and confidentiality of all the participants were emphasized.
Results
The extracted analysis components are presented in Table 2. The components of the difficulties and strategies faced by FCGs in caring for PwDs in the two wards addressed in this study were classified into two themes and seven subthemes.
Vicious Cycle Due to Multiple Factors
The daily routine of PwDs is dramatically transformed after hospitalization. They are challenged by external events such as the change in their surroundings and ongoing medical treatments. As a result, their FCGs experience greater difficulties.
Communication disturbance
Communication disturbance refers to the difficulties that arise when FCGs, PwDs, paid caregivers from Southeast Asia, and healthcare professionals attempt to communicate.
PwDs are not able to express their needs clearly, nor can they understand other people's messages. Thus, their FCGs sometimes need to guess the meaning PwDs try to convey. Such communication barriers may lead PwDs to exhibit disruptive behavior. On the other hand, as PwDs are prone to forgetting things, FCGs must convey information repeatedly, which can be annoying.
He can't speak clearly, so he can't express his needs clearly. (Case 8)
He would keep asking me," Where is your wallet?" and I would tell him it was at my side. And, after 5 seconds he would ask again. This would drive me crazy. (Case 9)
In Taiwan, each hospitalized patient is required to be accompanied by someone. It is common for a patient's personal foreign caregiver to take turns with FCGs to provide care. However, the native language of foreign caregivers is often different from that spoken in the patient's home and hospital, leading to communication difficulties with the patients and healthcare professionals. This makes the situation extremely difficult and burdensome for FCGs.
The paid caregiver is a foreigner. She cannot communicate with my father (the patient). (Case 6)
There was no way for the foreign caregiver to understand some of the information given by the doctor. In such cases, we had to come and listen to what the doctor had to say. (Case 5)
Because of the busy schedule of healthcare professionals, FCGs must often wait to be given the latest information on the patient's condition. In addition, some FCGs said that healthcare professionals only explain the condition of PwDs under their care to key decision-making members.
No one could tell me the exact time when the physician would visit and discuss the patient's condition with me. Although there is a relevant time schedule posted on the wall, I found the time always changed. So, I did not trust it. The only thing I could do was to wait for the physician. (Case 4)
The doctor would not tell me because he thought that the daughter was the decision-maker. (Case 8)
Endless worries
FCGs not only feel exhausted by the disruptive behavior and lack of self-control during hospitalization of their PwDs but also expressed being concerned about the potential problems they expect to face after discharge.
PwDs are sometimes unwilling to cooperate during their medical treatments, which can cause delays. FCGs do not know how to facilitate treatment under these circumstances, which becomes a source of hardship.
The nurse asked me to measure my mom's urine. But, my mom would not cooperate. (Case 4)
If he is in a good mood, he attempts to cooperate with his rehabilitation program. But, when he's in a bad mood, he may keep twisting around in the bed. (Case 7)
The risk of accidents faced by PwDs is likely to be higher in unfamiliar surroundings. FCGs fear falls or accidents may happen when the PwD under their care engages in bedside activities. Because of this anguish, FCGs are sometimes reluctant to help them perform rehabilitation exercises at the bedside, which causes delays in the implementation of care plans.
She kept getting up to go to the toilet frequently. I was afraid that she would fall. (Case 2)
The nurse practitioner told me we had to let him out of bed to do rehabilitation exercises. But I was worried he would fall. (Case 6)
When disturbed by noises in their environment, PwDs are likely to respond by making unwelcome/annoying noises of their own. FCGs are concerned that such behaviors may affect the other people in a ward.
I remember that day in the ward when a stranger next to my mother-in-law's bed was talking on the phone, and she kept interjecting in the conversation. (Case 4)
He talked all the time, and I was so afraid he would disturb the other patients. (Case 7)
Dementia care puts enormous financial pressure on families both during hospitalization and after discharge. As FCGs are not available for care around the clock, paid caregivers are often called upon to assist with caregiving tasks. FCGs said that not every family in Taiwan can access public resources such as welfare and social services. In addition, trying to pay the costs involved in postdischarge care can seem like a never-ending battle, which adds to the distress felt by the FCGs for the future.
The financial pressure has been really heavy since we had to hire a 24-hour caregiver at NT$2400 a day, which is really stressful for us. (Case 8)
Although we have the Long-Term Care 2.0 Plan in Taiwan, these services are not very useful to us. (Case 9)
I don't know where it will be better for him to live after being discharged. Should he live at home, be transferred to another hospital, or go to a nursing home? (Case 8)
Inadequate care skills of paid caregivers
The inadequate care skills of paid caregivers refer to their inability to adequately assess the needs of PwDs and their lack of skills essential to providing appropriate care, which may exacerbate the condition of their care recipients. FCGs expressed particular concern regarding the safety risks to PwDs caused by inappropriate care provided by paid caregivers.
Most paid caregivers fail to accurately assess PwDs' needs and cannot properly satisfy their desires. The FCGs shared that PwDs become agitated when their needs are not properly met, and they worry that this situation may affect optimal care delivery.
I think when my father-in-law doesn't sleep well, he becomes more agitated. At such times, you need to comfort him. But the paid caregiver does not know this. (Case 7)
I ask him to nod, shake his head, or move his eyes because he cannot verbally express his meaning clearly. But I find that the paid caregiver is unable to do this. (Case 8)
Paid caregivers lack knowledge of dementia and thus use inappropriate patient care skills, which may worsen the care recipient's condition. FCGs said that some of the paid caregivers have scolded PwDs for their disruptive behavior, which increased the severity of their agitation and delirium.
[horizontal ellipsis]the last paid caregiver kept scolding him. (Case 8)
I found that, after being placed in her care, my father started crying and screaming often. You cannot know the quality of their caregiving, so I came to the hospital every day after getting off work to check on my father's condition. (Case 6)
Physical and psychological exhaustion
Although most FCGs desire to take good care of PwDs, their own physical limitations because of older age, chronic illness, or muscle weakness lead them to fall short of this goal. In addition, the frequent occurrence of unexpected events often leads to FCGs getting inadequate sleep.
The FCGs expressed often feeling exhausted caring for PwDs because of their own chronic health conditions. They also shared that many of their afflictions affected not only their physical condition but also their psychological health.
I have systemic lupus erythematosus and stroke. So, my biggest difficulty in taking care of him is that I can't do it well, although I am willing to do it. (Case 7)
The psychological pressure is really huge. (Case 8)
FCGs often need to take care of PwDs at night. At these times, they often do not dare to sleep soundly because they worry that the PwD may arise in the middle of the night and fall or remove their catheters.
I could not sleep all night because my mother kept repeatedly saying that she had to get up to pee. (Case 2)
We dare not fall asleep because we are afraid that he will pull out his catheter when no one is watching. (Case 7)
Do Everything
In the face of the difficulties involved in PwD care, FCGs do everything and develop their own unique strategies. These strategies focus mainly on meeting the PwDs' needs and seeking resources.
Management of the behavioral and psychological symptoms of dementia
Caring for a patient with BPSDs in a hospital can be a struggle. PwDs are unable to express their needs verbally and so often use disruptive, nonverbal behaviors. FCGs recognize the unexpressed needs that underlie these behaviors, which they then try to satisfy. They often use strategies such as keeping the patient company, distracting them, and comforting them. However, they also sometimes employ negative strategies such as threats.
You have to patiently observe his behavior and think about what he wants. (Case 6)
She felt insecure when she was in the hospital, so she had to have someone beside her. (Case 1)
Because we are Catholic, when I saw him like this (uncooperative during the treatments), I would read the Bible out loud or pray with him. Then, he calmed down. (Case 8)
His son[horizontal ellipsis]bought him his favorite dessert. He became peaceful after eating the dessert. (Case 3)
When she was agitated, I often said to her, "If you don't cooperate, you can't go home." Then she became quiet. (Case 2)
Constant accompaniment of the patient
FCGs are hesitant to leave the PwD in their charge alone because they fear that, without them by their side, the PwD may have an accident. Even if FCGs only leave for a short time, they are concerned about harm coming to the PwD and so try to find someone to watch them or ask a nurse for assistance.
I had to keep watching him because I was afraid that he would pull out the tube. (Case 5)
He would follow others. He got lost like that before. So, I couldn't let him out of my sight. (Case 9)
When I left to buy food, if no other family member was there, I often asked a nurse to help me watch her. (Case 2)
Seeking sources of support
The competence and energy of FCGs are limited, so they require assistance from outside sources such as other relatives, long-term care resources, and hired manpower. Emotional or material support is also regularly sought, all of which are very valuable.
My aunt's daughter taught me how to take care of him because she is a nurse. (Case 7)
My mother has four children, and three of them are in Tainan (near the hospital). We cooperate with each other very well. (Case 2)
Some FCGs hired paid caregivers to help care for the PwD in their charge during hospitalization. They found that this resource reduced their burden, which allowed them to rest.
I felt that the paid caregiver really helped us a lot and allowed me to take a break. (Case 7)
Discussion
To the authors' knowledge, this is the first study designed to explore the difficulties encountered and the coping strategies used by FCGs who are responsible for PwD care and accompaniment during hospitalization in Taiwan. The focus of this study differs from that of studies conducted outside Taiwan, which largely have focused on the experience of FCGs with regard to the dementia care provided by hospitals. The following discussion is organized in the same order as the information presented in the previous sections on the themes and subthemes of this study.
Vicious Cycle Due to Multiple Factors
Communication disturbance
The findings indicate that the subtheme of "communication disturbance" involves three types of communication problems in the relationships among FCGs, PwDs, paid caregivers, and healthcare professionals. First, because dementia affects the language area of the brain, the effects of acute illness may significantly impede a patient's ability to convey their ideas (Alzheimer's Association, 2022).
The second problem involves paid caregivers in Taiwan, most of whom are foreigners who face obstacles to communicating with other care stakeholders. Because they speak languages different from those spoken in Taiwan, foreign caregivers cannot accurately convey their meanings to healthcare professionals or clearly understand the information received from healthcare professionals. Asis and Carandang (2020) studied immigrant caregivers working in Japan and found they faced huge difficulties during the caregiving process that were attributable to language differences.
The final type of problem affects FCGs, not all of whom are the primary decision-makers for the well-being of PwDs in their charge. This situation hinders the access of FCGs to the latest updates on and understanding of the PwD's condition. This is consistent with a study by the Alzheimer's Society (2009), which pointed out that more than 40% of FCGs were not allowed to participate in medical decision making. Furthermore, Burgstaller et al. (2018) found that healthcare professionals do not volunteer relevant information on PwDs. The FCGs in this study stated they felt excluded from knowing about medical decisions affecting PwDs in their charge.
Endless worries
The well-being of PwDs is a constant source of worry for their FCGs, as are the opinions that other people have of the PwD and the FCGs' lack of resources. PwDs' disruptive behavior may cause them to be uncooperative during treatment, which may cause accidents and bother others who are trying to rest nearby. For example, disruptive behavior has been shown to produce severe negative outcomes such as falling and getting lost, which accelerates disease progression (Parke et al., 2016; Rowe, 2008). It is also true that most people do not understand dementia well and cannot empathize with related behaviors. Therefore, FCGs must not only bear the pressure of caring for PwDs but also be wary of what happens around them.
These findings are consistent with those of a study by Hynninen et al. (2015) conducted on a group of Finnish FCGs responsible for PwD care. They found that FCGs not only were worried that their patient's disruptive behavior would bother others but also experienced shame as a result. Similarly, because of the influence in Taiwan of traditional Chinese cultural values grounded in collectivism and Confucianism (Hwang, 2009; Ting-Toomey & Kurogi, 1998), inappropriate behaviors instigated by PwDs in the hospital may be viewed as scandalous. Finally, as PwDs are more difficult to care for than many other patients (Clissett et al., 2013), the severity of dementia-associated BPSDs and the interference problems associated with BPSDs coupled with the low birthrate in Taiwan leave FCGs to face a difficult situation with inadequate resources.
Inadequate care skills of paid caregivers
The FCGs expressed concern that foreign caregivers were not capable of truly understanding the demands of PwDs, lacked sufficient caregiving skills, and thus may actually hinder the provision of optimal care. Little training on assessing and understanding the needs of PwDs is provided to foreign caregivers working in Taiwan. According to Kovach et al. (2005), PwDs commonly use disruptive behaviors to communicate frustration associated with unmet needs. However, a scoping review designed to examine the experience of foreign caregivers of PwDs living in long-term care facilities found that foreign caregivers in some cultural contexts believe PwDs exhibit disruptive behavior intentionally, with the primary goal of annoying their caregivers (Adebayo et al., 2020). Consequently, both a limited understanding of dementia and negative cultural attitudes may limit the ability of foreign caregivers to provide sufficient care to PwDs.
Physical and psychological exhaustion
Because of the dramatic changes in PwDs' needs and conditions caused by hospitalization, the FCGs in this study experienced frequent sleep interruptions and were constantly in a state of high alert to be ready to prevent accidents. As a result, FCGs were often under heavy pressure and felt exhausted. This finding aligns with those of Clissett et al. (2013), who studied a group of caregivers of hospitalized patients. They found that FCGs felt caring for patients with cognitive impairments to be more distressing than caring for those without these impairments. In addition, it has been shown that when caregivers who experience poor health are placed in a high-pressure and unfamiliar environment, they tend to develop physical and mental problems such as fatigue, depression, and insomnia, which decreases their quality of life (Beardon et al., 2018). People tend to ignore these possible impacts, which transforms FCGs into "invisible patients." Furthermore, filial piety is a culturally important concept in ethnic Chinese societies. Thus, FCGs in Taiwan may feel they would be shirking their duties if they do not take good care of their parents. In addition, the cultural concept of "face" may cause Taiwanese FCGs to fear being labeled as unfilial, further increasing their psychological distress (Chiu & Chang, 2018).
Do Everything
Management of the behavioral and psychological symptoms of dementia
FCGs have a better understanding of the history and preferences of the PwDs in their charge than others because they have lived and interacted with them for a long time and are familiar with their idiosyncrasies. Kovach et al. (2005) suggested that the disruptive behaviors of PwDs are manifestations of unmet needs, which are generally rooted in background factors (e.g., neurological and cognitive impairments) and more-proximal factors (e.g., pain, fatigue). Therefore, when PwDs are not able to convey their desires clearly, they may exhibit unreasonable patterns of behavior. This finding aligns with those of other studies that have found fully understanding the needs of a PwD to be a key feature of person-centered care (Burgstaller et al., 2018; Moyle et al., 2011).
Constant accompaniment of the patient and seeking sources of support
Because of their close relationship, the two remaining subthemes are discussed together in this section. As PwDs face a higher risk of accidents in unfamiliar surroundings, caregivers feel obligated to ensure they are not left alone and either try to constantly remain with the PwD or seek assistance from official and unofficial sources of support. Some caregivers are extremely appreciative of the efforts of healthcare professionals to provide assistance and some temporary relief from the responsibilities of caregiving, according to Beardon et al. (2018). Our study finding may be partially explained by hospital regulations. However, in the Taiwanese context, this finding may also be explained by the cultural belief that, because the family is the fundamental unit of society, taking care of sick family members is a core responsibility (Chan, 2010; Ting-Toomey & Kurogi, 1998). The FCGs in this study tended to seek help from other family members before looking to others for help (e.g., hiring an outside caregiver or entrusting care to healthcare professionals). This finding is consistent with Sakanashi et al. (2021), who found that Japanese FCGs of community-dwelling PwDs developed ways to strengthen themselves from caring experiences, and they build relationships based on a mutual understanding of their adversity.
Limitations
The interviewer is a relative of a former PwD. Thus, her preexisting understanding and prior experience may have introduced presuppositions, biases, and a fixed mindset into the interview process. Conscious of this possibility, the interviewer continually reflected on how this past exposure to the context under observation may influence the study. This "setting aside" of the interviewer's preexisting understanding opened the possibility of experiencing new impressions, which helped her eliminate potential blind spots and increase the objectivity with which study data were interpreted.
Conclusions
The clarification in this study of the problems faced by their FCGs can facilitate the provision of more appropriate, better targeted care by healthcare professionals. In addition to meeting the needs/demands of PwDs, high-quality inpatient care must also take into consideration the needs of the person(s) accompanying the patient, who in some cases are foreign caregivers requiring education and training in both language communication and dementia care skills.
Relevance to Clinical Practice
Future research should expand the pool of participants to include healthcare professionals, paid caregivers, and PwDs to better identify the related difficulties and strategies from all relevant perspectives to formulate optimal, high-quality care plans. Moreover, others (e.g., healthcare professionals working in medical and surgical wards) may have specific difficulties that should be considered as well. In addition, related training programs should focus on improving BPSD-related communication and management skills. Furthermore, cultural competence training programs should also be developed to foster attitudes conducive to working effectively in cross-cultural environments. In the ward, healthcare professionals may provide educational information to caregivers via online platforms, brochures, and/or leaflets; assist FCGs to obtain adequate resources; and invite FCGs to participate in the care plan development process. With this in mind, the government should increase public awareness of dementia to better foster a dementia-friendly social environment.
Author Contributions
Study conception and design: KXC, JJW
Data collection: KXC
Data analysis and interpretation: KXC, PCH, FPL
Drafting of the article: KXC, JJW
Critical revision of the article: JNL, JJW
References