Adaptation , linguistic and clinimetric validation of the Bangla version of Zarit Burden Interview

The aim of this study was to develop a culturally adapted and validated Bangla version of Zarit Burden Interview (ZBI-B) questionnaire for use in Bangla speaking caregiver of patient with dementia. This study was conducted on 100 caregivers related to consecutively attending outpatients with a previously established primary diagnosis of dementia, according to DSM-IV criteria. Validity and reliability were evaluated by comparing with the caregiver burden inventory (CBI). An exploratory factor analysis with the principle component with varimax rotation was used to detect the factorial structure in observed measurements. To attain the best-fitting structure and the correct number of factors, the following criteria were used: Eigen values >1.0, factor loadings >0.30. The Cronbach’s alpha value was 0.847 for test and 0.839 retest. The intra-class correlation for the test-retest reliability was 0.89. The ZBI score was highly correlated with the CBI score (Pearson’s correlation coefficient, r = 0.909, p = 0.001). From the exploratory factor analysis six factors comprising 20 items were extracted with Eigen values higher than 1.00 accounting for 69% of the total item variance. In conclusion, ZBI-B is valid, reliable and useful for use in clinical contexts and in future studies that could lead to a better understanding of caregiver burden in dementia. Article Info Depart e t of Psy hiatry, Holy Fa ily Red Cres e t Medi al College, Eskato Garde , Dhaka, Ba gladesh FR ; Depart e t of Psy hiatry, Fa ulty of Medicine, Ba ga a dhu Sheikh Muji Medi al U i ersity, Shah ag, Dhaka, Ba gladesh JSN, MSIM, HUA For Corresponden e: Farza a Ra i drfarza ara i @yahoo. o Re ei ed: O to er A epted: No e er A aila le O li e: De e er ISSN: O li e Pri t


Introduction
Psychiatric patients need assistance or supervision in their daily activities and this often places a major burden on their caregivers, thereby placing the caregiver at a great risk of mental and physical health problems. 1 Identifying the challenges and potential impacts of caregiving will facilitate the plan of management or care of the patient.
Several scales are already developed to measure caregiver burden based on experience of different country. 4,9-12The Zarit Burden Interview (ZBI), which provides a comprehensive assessment of both objective and subjective burden, is one of the most commonly used burden measures and has been validated in many culturally or ethnically different populations.The ZBI was primarily developed to measure subjective burden among the caregivers of people with dementia. 4ere is still no validated instrument to measure the caregiver burden in Bangladesh.

ZBI-B
The ZBI is a 22 item instrument for measuring the caregiver's perceived burden of providing family care. 4The 22 items are assessed on a 5 point Likert scale, ranging from 0 = 'never' to 4 = 'nearly always'.Item scores are added up to give a total score ranging from 0 to 88, with higher scores indicating greater burden.The questions focus on major areas such as caregiver's health, psychological well-being, finances, social life and the relationship between the caregiver and the patient.

Bangla version of caregiver burden inventory
Burden of caregivers was also assessed with another instrument "Caregiver burden inventory" (CBI). 12e investigator administered the inventory by reading the statement and marking the responses.It is a 24 item multi-dimensional questionnaire measuring caregiver burden with 6 subscales: a) Time dependence; b) Developmental; c) Behavior; d) Physical burden; e) Social burden; and f) Emotional burden.Scores for each item were evaluated using a 5 point Likert scale ranging from 0 (not at all disruptive) to 4 (very disruptive).

Procedure of the data collection
One hundred diagnosed cases of dementia were selected from the Dementia Clinic at the Neurology and Psychiatry Outpatient Department.One of his/ her selected caregivers was enrolled.When more than one caregiver of a particular patient were attended, who contributed more was selected by the researcher.After taking informed written consent, the socio-demographic information of patient and caregiver was documented in the questionnaire to identify the socio-demographic characteristics by face to face interview.
The caregivers were asked to self-administer the ZBI-B questionnaire that comprised questions assessing demographics and some standardized instruments including the ZBI.Although the questionnaire was designed to be self-administered, the subject was first given an explanation and rundown on the questionnaire by the investigator before being left to complete the questionnaire.The same caregiver was also asked to fill-up the questionnaire second time 2 weeks after completion of first survey for the assessment of test-retest reliability.Another scale CBI was also used by investigator to test the validity by asking questions and filling up the response.

Cross-cultural adaptation 13
Stage I: The ZBI questionnaire was translated initially by two persons (T1 by a medical person and T2 by a person who had no medical or clinical background).
Stage II: Two translations were synthesized into one translation (T-12).
Stage III: This part (T-12) was translated back to the original (English) (BT1 and BT2) by two individuals who had competency on both Bangla and English.
Stage IV: To consolidate all the versions of the questionnaire and to develop what would be considered the prefinal version of the questionnaire for field testing an expert committee was formed.The committee was composed of methodologists, health professionals (psychiatrist and clinical psychologists), language professionals, and the translators (forward and backward translators) involved in the process up to this point.The committee reviewed all the translations and reach a consensus on any discrepancy.The material at the disposal of the committee includes the original questionnaire, and each translation (T1, T2, T12, BT1, BT2) together with corresponding written reports (which explain the rationale of each decision at earlier stages).

Stage V (Pretesting):
The final stage of adaptation process was the pretest.This field test of the new questionnaire used the prefinal version in 30 subjects or patients from the Neurology and Psychiatry Outpatient Department.Each subject completed the questionnaire, and was interviewed to probe about what he or she thought was meant by each questionnaire item and the chosen response.Both the meaning of the items and responses were explored.

Assessment of validity and reliability of ZBI-B
Caregivers (n=100) aged ≥18 years attending patients with dementia were evaluated thoroughly.All were asked for occupation, level of education and social status.ZBI-B questionnaire was served individually.The reliability of the ZBI-B was assessed by test-retest reliability test, the concurrent validity and face validity were seen by comparing with CBI.

Ethical issue
Patients and all caregivers were informed about the purpose of the study and ethical issues were explained.The study protocol was approved by Institutional Review Board of Bangabandhu Sheikh Mujib Medical University.We have contacted the author and the permission was taken for validation of its ZBI-B.

Results
Mean ZBI score of individual item ranged from 0.1 ± 0.4 to 2.1 ± 0.9.The highest score was 2.1 ± 0.9 for the item 7 "Are you afraid what the future holds for your relative?"followed by item 21 "Do you feel you could do a better job in caring for your relative?"(1.9 ± 1.1) and item 20 "Do you feel you should be doing more for your relative?"(1.9 ± 1.0)  IV).In principle, component analysis six components Eigen values greater than one and this six components explain the total variance is 68.9 (Table V).

Reliability and validity
The Cronbach's alpha value was 0.847 for test and

Factor analysis
Exploratory factor analysis on the ZBI-B was performed based on the principle component method with a varimax rotation, to detect the factor structure in the observed variables.From the exploratory factor analysis six factors comprising 20 items were extracted with Eigen values higher than

Discussion
The ZBI has been translated into many languages-Chinese, 14 Japanese, 15 Italian, 16 Korean, 17 German, 18 Brazilian 19 and Turkish 20 and has been adopted for assessing caregiver burden in many different patient populations, for example dementia, cancer populations, psychiatric illness, multiple sclerosis, stroke, Parkinson's disease and chronic obstructive pulmonary disease.Currently, a Bangla version of the ZBI is not available and the present study therefore aims to validate the Bangla version of the 22 item ZBI (ZBI-B), evaluating its reliability, calculating its internal consistency and concurrent validity.It was studied on 100 caregiver of people with dementia measuring caregiver burden with ZBI-B and comparing that with CBI (caregivers burden inventry). 12 the current study minimum and maximum total ZBI-B score was 10.0 and 61.0 and mean score of 27.3 ± 11.2 for test and 27.2 ± 10.8 for retest, which are comparable to those reported by Zarit et al. 4 and other validation studies.determined their Turkish version of the ZBI had a three-factor structure with an Eigen value of >1.In the current study, the first factor accounts for the majority of the variance and has the majority of the items loading on to it, followed by the second factor.Even if this instrument shows a high internal consistency it seems to have a multi-factorial structure.The reports of high internal consistency and multiple subfactors are not necessarily contradictory, because psychometric theory shows that a multi-factorial scale can achieve high α levels if the items are evenly apportioned across the subscales.Two items (3 and 9) have not been found to be fit for any factor of ZBI-B.
Pearson correlation for test-retest reliability of ZBI-B was r=0.896 (p=0.001).The acceptable minimum point for test-retest reliability is 0.70 according to previous literature. 28The Zarit Burden score was highly correlated with the CBI score (Pearson's correlation coefficient, r=0.909, p=0.001).

Conclusion
The results of this study indicate good psychometric properties of the ZBI-B.

Figure 1 :
Figure 1: (A) Correlation of ZBI-B test score with ZBI-B retest score.Pearson's correlation show that ZBI-B score is significantly correlated with its retest score.(B) Correlation of ZBI-B score with CBI score.Pearson's correlation show that ZBI-B score is significantly correlated with CBI score

Mullick, Helal Uddin Ahmed and Nafia Farzana
A Jour al of Ba ga a dhu Sheikh Muji Medi al U i ersity, Dhaka, Ba gladeshAdaptation, linguistic and clinimetric validation of the Bangla version of Zarit Burden InterviewFarzana Rabin, Jhunu Shamsun Nahar, Mohammad S. I.

Table IV ZBI intraclass correlation and Cronbach's alpha
0.839 retest which was examined with 95 subjects.The intra-class correlation for the test-retest reliability, which was examined with 95 subjects, was 0.89 (When interpreting Cronbach's alpha or the intra class R, a value >0.7 reflects good reliability).

Table V Analysis of principle components
16,21-24 "Are you afraid what the future holds for your relative?"item 7 had highest mean ZBI score, similarly in previous studies it had high burden score. 16,18,21,24In those studies item 8 "I feel the patient is too dependent"

Table VI Rotated component matrix by principle component analysis
27 variance.Item 3 and 9 of the do not represent any factor in original ZBI version and not suitable in the Bangla version.In previous studies for Chinese version five factors had an Eigen value greater than 1.00 and accounted for 56.4% of total variance, for Italian version five factors comprising all 22 items were extracted with Eigen values higher than 1.00 accounting for 60% of the total item variance.İnci and Erdem27