C. Social Support and Social Activity
Ⅲ. MATERIALS AND METHODS
A. Research Model and Hypothesis
To look at the investigated contents from the precedent studies, as the cause that is identified most importantly about dementia patient caregiver’s depression, patient state is being emphasized (Jang, 2013; Hong, 2016), and caregiver activity (Kim, 2000; Bae et al., 2018) and burden (Pearlin, 1990;
Tennstedt, McKnightly and Sullivan, 1989) are also reported as the factors that have an impact on depression.
And based on the studies that social support and social activity have a positive impact on dementia patient caregiver (Park and Park 2015; Rho and Mo, 2007; Lee et al., 2004) as well as the studies that patient state causes care activity (Kwon et al., 2002), the studies that patient state also has an impact on care burden (Song et al., 2013; Bae et al., 2006), and the studies that there is a significant relationship between care activity and care burden (Song et al., 2013; Kwon et al., 2015), this study set the conceptual model like in <Figure 1> below.
<Figure 1> Conceptual Model
In the research model set up, as the cause that is identified most importantly about the dementia patient caregiver’s depression, patient state is being emphasized (Jang, 2013; Hong, 2016), and based on the investigated contents from the precedent studies that caregiver activity (Kim, 2000; Bae et al., 2018) and burden (Pearlin, 1990; Tennstedt et al., 1989) are the factors that have an impact on depression, the studies that patient state has an impact on care burden (Song et al., 2013; Bae et al., 2006), and the studies that there is a significant relationship between care activity and care burden (Song et al., 2013; Kwon et al., 2015) and the studies that patient state causes care activity (Kwon et al., 2002), we presented the following direct effect hypothesis and the direct effect hypothesis model like in <Figure 2>.
<Figure 2> Hypothesis Model: direct effect
H1-1. Dementia patient state will have a significant impact on caregiver depression.
H1-2. Dementia patient state will have a significant impact on caregiver’s activity.
H1-3. Dementia patient state will have a significant impact on caregiver burden.
H1-4. Dementia patient caregiver’s activity will have a significant impact on the burden that they feel.
H1-5. Dementia patient caregiver’s activity will have a significant impact on their depression.
H1-6. Dementia patient caregiver’s burden will have a significant impact on their depression.
Inferring from the investigated contents from the precedent studies so far and the Research Hypothesis H1, we presented the following mediating effect hypothesis and the mediating effect hypothesis model like in <Figure 3>.
<Figure 3> Hypothesis Model: mediating effect
H2-1. Caregiving activity will have a significant mediating effect in the relationship between dementia patient state and caregiver depression.
H2-2. Care burden will have a significant mediating effect in the relationship between dementia patient state and caregiver depression.
H2-3. Care burden will have a significant mediating effect in the relationship between dementia patient caregiver’s activity and depression.
Furthermore, based on the studies that social support and social activity have a positive impact on dementia patient caregiver (Park and Park, 2015;
No and Mo, 2007; Lee et al., 2004), we presented the following moderating effect hypotheses and the moderating effect hypothesis model like in
<Figure 4>.
<Figure 4> Hypothesis Model: moderating effect
H3-1. Social support will have a significant moderating effect on each route between dementia patient state, caregiver’s activity, burden, and depression.
H3-2. Social activity will have a significant moderating effect on each route between dementia patient state, caregiver’s activity, burden, and depression.
B. Operational Definition of Variables and Configuration of Measurement Tools
1. Depression
Depression refers to emotional disturbance representing worry, gloom, lethargy and valuelessness ranging from emotional mood changes to pathological condition (Beck et al., 1961).
This study tells the scores measured by BDI.
BDI screening test is a depression diagnostic scale that measures the depressive symptom, developed by Beek(1961) and composed of 21 question items including cognitive, emotional, synchronous, and physical symptom areas of depression.
By comprehensively summarizing the symptoms that appear a lot in depressed patients who receive psychotherapy and patients’ attitudes, we extracted 21 question items and scaled them. Subjects were asked to
respond to the specific statements representing the degree of symptom for each question item.
They are encouraged to choose the contents that represent their mood state the best for the past one week among the four items summarized by symptom. Each question item was scored in a 4-point scale ranging from 0 to 3 point and evaluated in the category of 0-63 point.
To look at the content and score of the first question item, I don't feel sadness =0 point, I feel sadness =1 point, I always feel sadness and can’t dispel it=2 point, and I am so sad and unhappy and can’t endure it=3 point.
In interpreting the result, the cutting point for diagnosing the depression is presented at 21 point in Korea. But in general, 0-9 point is understood as non-depressed state, 10-15 point as mild depression state, 16-23 point as heavy depression state, and 24-63 point as severe depression state.
As a result of reliability analysis of 21 question items for depression conducted in this study, it was found that Cronbach's α was .971, which showed a high reliability.
2. Dementia Patient State
Most studies pointed out that dementia elderly’s functional disturbance is the primary care burden inducing factor, based on whichever conceptual definition, among various concepts on care burden. Especially dementia elderly’s functional disorders, the cognitive disorders including memory disorder, disorientation, and impaired judgment and the accompanying psychiatric symptoms and problem behaviors are regarded as the most central care burden inducing factors.
In this study, dementia patient state means a value identified by measuring S-SDQ, NPI, S-ADL, and S-IADL.
(A) Patient’s Cognitive Function (S-SDQ)
Cognitive function refers to memory, orientation, attention, language, perception and neuromotor function (Kim et al., 2005). In this study, we used the score measured by S-SDQ developed by Choi et al.(1996). This instrument consists of 15 question items measuring patient’s cognitive function state and daily activity function based on the reports by the families living with the dementia patient. Total sum of the scores for question items was 30 point. If the score is 8 point or higher, dementia is suspected. This instrument has an advantage in that it can distinguish the possibility of dementia in a short time and is relatively less influenced by patient’s education level and age. But it has limitations in that patient evaluation can depend on the families who are subject to the test and the test only relies on the questionnaire without face to face with the patient.
As a result of reliability analysis of 15 questions for patient’s cognitive function conducted in this study, it was found that Cronbach's α was .932, which showed a high reliability.
(B) Patient’s Problem Behavior (NPI)
This study measured patient’s problem behavior with the Neuropsychiatric Inventory (NPI). The formula of scoring is frequency of behavior symptom (0, 1) multiplied by severity (1=mild, 2=moderate,
3=severe). This means that the higher the total score, the more severe the overall problem behavior. Also the caregiver’s level of pain by item (0=not at all, 1=very low, 2=mild, 3=moderate, 4=severe, 5=very severe) was evaluated and the obtained value was multiplied by patient’s problem behavior for calculating the total score. The higher the total score, the bigger the caregiver’s pain.
Neuropsychiatric Inventory was evaluated with more than 12 abnormal behavior symptoms that appear commonly in the dementia patients -delusion, hallucination, agitation/aggression, depression/dysphoria, anxiety, euphoria/elation, disinhibition, irritability/instability, apathy/indifference, aberrant motor behavior, sleep/night-time behavior, appetite/eating change, and simultaneously subsequent caregiver’s level of pain is evaluated. This is not only useful for evaluating the psychopathology of dementia but also helpful for determining the type of dementia and observing the changes of symptom depending on treatment effect. Moreover, it has a big advantage in that caregiver’s level of pain can be evaluated and this can be reflected into treatment.
As a result of reliability analysis of patient’s problem behavior conducted in this study, it was found that Cronbach's α was .951, which showed a high reliability.
(C) Patient’s Activities of Daily Living Evaluation (S-ADL, S-IADL)
The skill required for human’s daily activities consists of daily activity skills-basic required for taking care of one’s body and daily activity skills-instrumental required for enjoying social activity. In this study, we
measured the daily activity skills-basic and the daily activity skills-instrumental through the interview with patient caregivers by the clinicians who were well-informed of how to implement, with S-ADL and S-IADL developed by Gue et al.(2004).
Total score of S-ADL ranged from 0 point to 24 point. This means that the higher the score, the more difficult the independence performance of the daily activity skills-basic. S-IADL consists of 15 question items in a 0~3 point scale. The score range is from 0 point to 45 point. and the sum of raw scores is calculated before evaluation. Therefore, the higher the score of S-IADL, there is more disturbance in daily activities-instrumental.
Also considering the cultural difference or gender difference, it was divided into ‘currently executing’ and latent ability for evaluation. “Currently executing” is the degree that the patient currently can perform the instrumental daily activities independently. On the other hand, “latent ability” is the ability to perform considering the patient’s latent ability despite the current inability to perform the instrumental daily activities independently.
The score range of S-IADL was from 0 point to 45 point. This means that the higher the score is, the performance of instrumental daily activities required for social life deteriorates.
As a result of reliability analysis on patient’s daily activities evaluation conducted in this study, it was found that Cronbach's α (basic) was .942 and Cronbach's α (instrumental) was .952, which showed a high reliability.
3. Care Activity
To measure care time, two methods have been used: recording the total time used for helping with dementia patient’s activity and fragmenting the time used for helping with a certain activity. The example for the latter is represented by Caregiver Activities Time Survey and CAS(Caregiver Activity Survey).
CAS was designed to investigate the information on the time that dementia elderly supporters spared for the past 24 hours from the time of the investigation (Davis et. al.,1997). CAS was segmented into the following six subareas related to assistance with dementia patient’s activities of daily living and behavioral management: communicating with the person, using transportation, dressing, eating, looking after one's appearance, and supervising the person. In this study, we measured by recording total hours a day.
4. Care Burden
Care burden is defined as a physical and mental or psychological or emotional/social/economic problem experienced by the family members who take care of the elderly who are disabled (George and Gwyther, 1986). In this study, we used the score measured by Zarit et al.(1986)’s Zarit Burden Interview. This scale is composed of total 22 question items asking caregivers how they felt about health, finance, social life, and interpersonal relationship while looking after the dementia patient. The type is a self report, and the responses to the question how often caregivers feel about each question were scored at “not at all=0”, “very occasionally so=1”,
“sometimes so=2”, “often so=3”, and “almost always so=4.” The total score
was 88 point. Usually, 0-20 point is classified as no burden or extremely mild, 21-40 point as mild to moderate, 41-60 point as moderate to severe, and 61-88 point as severe. This means that in general, the higher the score, the bigger the care burden. If it is 51 point or higher, the care burden means rather high. If it is 69 point or higher, it means very high.
As a result of reliability analysis of care burden conducted in this study, it was found that Cronbach's α was .938, which showed a high reliability.
5. Social Support and Social Activity
Social support is a subjective thing recognized by the family care providers and thus refers to a physical and psychological help that subjects receive through interpersonal interaction with spouse, family, friend, and neighbor (Norbeck, et al., 1981). This study has three subfactors of emotional support, instrumental support, and care support for social support and classified the group into two groups: the group who receives social support perceived by individuals and the group who does not.
As a result of reliability analysis of social support conducted in this study, it was found that Cronbach's α was .606, which showed a moderate reliability.
Individual’s social participation activity is sometimes limited to one activity, but many people are participating in multiple social activities including socializing activity among relatives or friends, religious activity, sports activity, and volunteer work activity. Therefore, as the necessity of conducting a study encompassing the entire social participation activity rather than analyzing the effect of one social participation activity has been
raised (Jeon, 2017), social activity was used as the item for measuring the social activity participation level included in Aging Research Panel Survey.
The seven questionnaire items for identifying how often they participated in social activity for the past one month included meeting with relatives, friends, and neighbors, participation in religious gathering including church, Catholic church, and temple, leisure activity, club and social gathering, political/social organization participation, learning/teaching activity, and volunteer work activity, and the presence of care for the others other than patient was scored in the following manner: not at all=0, once a month=1, 2~3 times a month=2, once a week=3, 2~3 times a week=4, and 4 times a week or more=5, and the group was divided into two groups: the group who participated in social activity a lot and the group who did not for analysis.
As a result of reliability analysis of social activity conducted in this study, it was found that Cronbach's α was .642, which showed a moderate reliability.
6. Configuration of Survey
In this study, the important variables are patient state, caregiving activity, care burden and depression, and social support and social activity.
Accordingly, this study extracted the items that were important variables for this study and conducted analysis based on the questionnaire items of CREDOS.
The questionnaire items in the measurement tools used for this study are like in <Table 1> below.
<Table 1> Questionnaire items
Dependent variable depression was composed of 21 question items and independent variable patient state was composed of largely 15 question items for cognitive function, 12 for problem behavior, 15 for activities of daily living-basic, and 12 for activities of daily living-instrumental (total 44). Intervening variable caregiving activity was composed of largely two items: 1 for time and 1 for number of days. And mediating variable care
Constructs Variables Number
of items Supporting literature
Careegiver Depression BDI 21 Beek(1961)
Dementia patient
burden was composed of 22 items, and moderating variable social support was composed of 3 items and social activity of 7 items. Personal background was composed of total 5 items including gender and age.
Therefore, the total number of questions was 114.
C. Data Collection and Analytical Procedure
1. Data Collection
This study used the data from The CARE Study: Caregivers of Alzheimer’s Disease Research. The survey was conducted in cooperation with 12 medical institutions nationwide including Ajou University Hospital, Gachon University Gil Medical Center, Bucheon St. Mary’s Hospital Catholic University, Konkuk University Medical Center, Kwandong University Myungji Hospital, National Health Insurance Ilsan Hospital, Dong-A University Medical Center, and the questionnaire was administered in one-on-one interview by trained nurses.
The subjects selected were the main caregivers of the patients who were included in the patient inclusion criteria. The family members (spouse, daughter-in-law, daughter, son, etc) who spent the most time in looking after the patient were selected. The patient inclusion criteria included subjects of follow-up investigation who were registered in the CREDOS(Clinical Research Center for Dementia of South Korea) database, and they were the patients who were diagnosed with Alzheimer's disease or subcortical vascular dementia. The period of investigation was from
2012 till 2013 as first year survey, and among 600 main caregivers of the patients who are residing at home at the point of survey, 476 caregivers only were used for our final analysis.
And interview research was conducted after signing the informed consent and approved from the Ajou University Medical Center Institutional Review Board(AJIRB-MED-SUR-12-046).
2. Analytical Procedure
The analytical procedure conducted in this study is as follows:
First, for refining the data used in this study, we conducted a missing value test, normality test, and outlier test. The samples whose response rate was low in the missing value test were removed by the Listwise deletion method, but in nature of survey content, the presence of missing values should also be considered and so some missing values were allowed. For normality test, skew and kurtosis were drawn And it was found that skew was less than 2, absolute value and kurtosis was less than 4, absolute value. For the items beyond the normality, we conducted outlier test, and the samples that were outliers beyond IQR*1.5 were removed by the Listwise deletion method.
Second, for identifying the sociodemographic status of the subjects surveyed, we conducted frequency analysis.
Third, for identifying the validity of the measurement tools, we conducted confirmatory factor analysis. At this time, some missing values were allowed. So we used FIML(Full Information Maximum Likelihood).
Fourth, for hypothesis testing, we conducted structural equation modeling
analysis. For mediating effect testing, we conducted Sobel test, and for moderating effect testing, we used the parametric comparative analysis from the multiple group analysis.
The analysis so far was conducted with statistical package programs SPSS 20.0 and AMOS 20.0.
Ⅳ. RESULTS
A. Demographic Status of Subjects Surveyed
The number of subjects who responded to the survey for this study was 600 individuals in the beginning, among which, the samples who were removed by the Listwise deletion method because the response rate was low or the response was odd was 124. Therefore, the final sample for the analysis was 476 individuals, and the results of frequency analysis conducted for identifying such sociodemographic status appeared like in
<Table 2> below.
Among the total 476 individuals, there were 154 males (32.4%) and 322 females (67.6%). In the relationship with dementia patient, spouse occupied 183 individuals (38.5%), which was the highest, daughter 127 (26.7%), daughter-in-law 82 (17.2%), and son 72 (15.1%). In average monthly income level, 1.5 ~ 3.5 million won occupied 185 individuals (39.0%), which was the highest. In academic ability, high school graduate occupied 170 individuals (35.7%) and college graduate 161 (33.8%). The care period for dementia patient was 4.3 years on average, 26.5 days on monthly average, and 14.1 hours on daily average. And care burden showed 40.5 point on average in the range from point 0 to point 88, and depression showed 14.1 point on average in the range from point 0 to point 59.
<Table 2> Characteristics of Caregiver
Categories mean ± SD / N (%)
Age (y) 57.0 ± 13.0
Gender
Male 154 (32.4)
Female 322 (67.6) Relationship to patient Spouse (M) 76 (16.0) Spouse (F) 107 (22.5) Daughter-in-law 82 (17.2) Son 72 (15.1) Daughter 127 (26.7) Others (Son-in-law ) 12 (2.5) Monthly income(won) <150 153 (32.2)
150-350 185 (39.0)
≥350 136 (28.7) Education level No formal education 11 (2.3)
Elementary school 46 (9.7) Middle school 61 (12.8) High school 170 (35.7) College or university 161 (33.8) Graduate school 27 (5.5) Duration of caring (y) 4.3 ± 4.6 Caring day per month (d) 26.5 ± 8.2 Caring time per day (h) 14.1 ± 8.4
ZBI 40.5 ± 20.2
BDI 14.1 ± 10.0
* Characteristics of the categorical variables described as N (%), and characteristics of continuous variables described as Mean (SD)
And the results of descriptive statistic analysis conducted to look at the status of dementia patient state appeared as shown in the following
<Table 3>.
<Table 3> Dementia Patient state Categories mean ± SD
S-SDQ 21.3 ± 7.4 NPI 39.1 ± 36.1 S-ADL 5.9 ± 6.5 S-IADL 28.5 ± 13.1
Cognitive function (S-SDQ) was at 21.3 point on average in the range from point 0 min. to point 30 max. Problem Behavior (NPI) appeared at 39.1 point on average in the range from point 1 min. to 180 point max.
And Activities of Daily Living-Basic(S-ADL) appeared at 5.9 point on average in the range from point 0 min. to 24 point max. and Activities of Daily Living-Instrumental (S-IADL) appeared at 28.5 point on average in the range from point 0 min. to 45 point max.
B. Confirmatory Factor Analysis
The measurement tools used in this study are depression, patient state,
The measurement tools used in this study are depression, patient state,