Skip to main content
NCBI home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2018 Jun 20.
Published in final edited form as: Arch Basic Appl Med. 2018 Feb 5;6(1):45–49.

Validation and Reliability of the 12-item Zarit Burden Interview among Informal Caregivers of Elderly Persons in Nigeria

OO Ojifinni 1,*, OC Uchendu 2
PMCID: PMC6010072  NIHMSID: NIHMS968406  PMID: 29938213

Abstract

Research on ageing in Nigeria has shown that informal care places economic and psychological strain on the caregivers of the elderly persons. However, objective method of assessment of the burden of care for the elderly among caregivers is lacking. This study was aimed at validating the 12-item Zarit Burden Interview (ZBI) among caregivers of elderly persons in Nigeria in correlation with the Katz Index of Independence in Activities of Daily Living (Katz-ADL), the General Health Questionnaire (GHQ-12) and the Modified Conflicts Tactics Scale for Elder Abuse (MCTS). Eighty primary caregivers of community-dwelling elders were selected using a two-stage cluster sampling from two communities. Principal component analysis with varimax rotation was used to determine the factor structure of the ZBI. Construct validity was assessed using Spearman’s correlations between the ZBI, the GHQ-12, Katz ADL and MCTS. Internal consistency and instrument reliability were examined with the Cronbach’s alpha split-half correlation. Three factors with eigenvalues greater than 1.0 were extracted on the exploratory factor analysis comprising all 12 items accounting for 68.0% of the total item variance. The reliability analysis gave a Cronbach’s α of 0.90 and a split-half correlation coefficient of 0.84. Spearman’s correlation (rs) showed good correlation between the ZBI scores and GHQ-12 (rs=0.44, p<0.001), MCTS (rs=0.43, p<0.001) and Katz ADL (rs= −0.50, p <0.001). The 12-item ZBI is a valid and reliable tool for assessing burden in informal settings among caregivers of elderly persons. The tool can be used to assess burden of care among caregivers of elderly persons in community settings.

Keywords: burden of care, Zarit burden interview, caregivers of the elderly, validity and reliability

INTRODUCTION

The proportion of elderly persons is increasing globally and this increase has been found to be greater in developing countries especially (Beach et al. 2010). The reduction in physical strength that occurs with ageing reduces the capacity of older people to work and increases their dependence on others for their daily needs (Ani 2014). The likelihood of having disabilities leading to dependence also increases with age due to the possibility of accumulating health risks across a lifespan of disease, injury and chronic illness (Beach et al. 2005, 2010). Care giving may therefore become burdensome to the caregiver and impact negatively on their health resulting in poor quality of care and in some instances abuse of the care recipient (Beach et al. 2005; Chattat et al. 2011). The experience of burden of care among caregivers may be modified by factors like the available support system, the level of dependence of the care recipient, socio-cultural demands and expectations as well as the socioeconomic ability of the caregiver.

Studies in developed countries have assessed the burden of care on caregivers of elderly persons who have some form of cognitive impairment (Brandl and Raymond 2012; Steadman, Tremont, and Davis 2007). In some instances, the burden of care has been related with the perpetration of elder abuse either within community settings or in institutions of care of the elderly (Cooper et al. 2010; Caciula et al. 2010). Findings from Gureje et al’s assessment of functional disability among elderly persons in Nigeria revealed that about 19% of the elderly persons were disabled (Oye Gureje et al. 2006). Many of these disabled elderly persons had an unmet need for care as there was no caregiver available to assist in their area of limitation (Oye Gureje et al. 2006). Other studies in Nigeria have examined the socio-cultural expectations from caregivers of elderly persons (Mudiare 2013; Sijuwade 2008; Ajomale 2007a; Uwakwe and Modebe 2007). The expectation is that the care of the elderly remains within the family whether or not the family members have the wherewithal to provide adequate care (Ajomale 2007a; Mudiare 2013; Oye Gureje et al. 2006). This form of informal care is usual within many African communities (Mudiare 2013). Research on ageing in Nigeria has shown that informal care often places a strain on the caregivers of the elderly persons both economically and psychologically (Oye Gureje et al. 2006; Mudiare 2013; Ajomale 2007b). However, research objectively assessing the burden of care for the elderly on the caregivers in this environment is lacking.

The Zarit Burden Interview (ZBI) is a standardized and validated tool, which has been used widely for the assessment of caregiver burden (Bedard et al. 2001; Flynn Longmire and Knight 2011; Braun et al. 2010). The tool has proven reliability for the subjective assessment of burden of caregivers of dementia patients in different settings (Bedard et al. 2001; Wang et al. 2008). Both the 22-item and the 12-item ZBI for the assessment of caregiver burden have been validated in different settings (Bedard et al. 2001; Flynn Longmire and Knight 2011; Wang et al. 2008; Cooper et al. 2009; Hirono, Kobayashi, and Mori 1998; Braun et al. 2010; Seng et al. 2010; Chattat et al. 2011; Ballesteros et al. 2012; Higginson et al. 2010). Higginson et al demonstrated that the 12-item ZBI performs as well as the 22-item ZBI in clinical conditions like advanced cancer, dementia, acute brain injury and palliative care (Higginson et al. 2010). The 12-item ZBI has however not been tested among informal caregivers of elderly persons with no clinical diagnosis of illness. The aim of this study was to validate the12-item version of the ZBI for use among informal caregivers of elderly persons irrespective of level of cognition within the Nigerian cultural context. The reliability of the ZBI for assessing burden of care experienced by the informal caregivers was assessed. The correlation of the ZBI with the Katz Index of Independence in Activities of Daily Living (Katz ADL) for the care recipients,(Wallace and Shelkey 2007; Katz et al. 1963) the 12-item General Health Questionnaire (GHQ-12) (O Gureje 1991; Chattat et al. 2011) and the Modified Conflicts Tactics Scale for Elder Abuse (MCTS) (Cooper et al. 2009, 2008) was also tested. Burden of care (measured by the ZBI) which may predispose caregivers to perpetrate elder abuse is determined by their perception of the level of disability of the elderly (measured with the Katz ADL), their ability to successfully handle conflict (measured using the MCTS) and their own mental health status (assessed by the GHQ-12) which may be affected by care giving. It is expected that the ZBI will be used in combination with the other three tools to assess the burden of care experienced by informal caregivers of elderly persons within communities or in health facilities.

MATERIALS AND METHODS

Ethical approval

Ethical approval for the study was obtained from the Oyo State Ministry of Health Ethics Committee. The approval number for the study was AD/13/479/794.

Methodology

This was a community-based cross-sectional study carried out in Oyo State, Nigeria between February and June 2016. Primary caregivers (aged 18 to 59 years) of community-dwelling elderly persons were selected by a two-stage cluster sampling from two communities (one urban and one rural). Stage one involved the selection of one rural (from 12) and one urban from (12) Local Government Areas (LGAs) in Oyo State by balloting. Ibarapa (rural) LGA and Akinyele (urban) LGA were the selected for the study. The second stage involved the selection of one out of 10 wards in each of the selected LGAs by balloting. The third stage was the selection of one community from each of the selected wards in the study LGAs by balloting. All eligible and consenting caregivers in the selected communities were interviewed. Health workers in the primary health care centres covering the selected communities assisted with the data collection.

Measures and instruments

Sociodemographic information was obtained from the caregivers using semi-structured, interviewer-administered questionnaires. Other aspects of the questionnaire were the 12-item ZBI (Bedard et al. 2001), the Katz ADL (Wallace and Shelkey 2007), the GHQ-12 (Craig Jackson 2007) and the MCTS for elder abuse (Cooper et al. 2008, 2009).

The Zarit Burden Interview

This study used the 12-item version of the ZBI to assess caregiver burden.(Bedard et al. 2001) The short version was preferred in this context for its length and easier administration. The 12-item ZBI had responses never, rarely, sometimes, quite frequently and nearly always graded from 0 to 4. The cut-off points for the varying degrees of burden for the short version were measured in quartiles with the first quartile equivalent to mild burden being three (3) followed by 9, the second quartile and 17, the third quartile (Bedard et al. 2001). The ZBI has been shown in different studies to have good construct validity and internal consistency, with Cronbach α ranging between 0.83 and 0.95 (Bedard et al. 2001; Chattat et al. 2011; Cooper et al. 2010). The internal consistency for the short version developed by Bédard et al was 0.88 and the findings were comparable to both the 22 and 18-item formats (Bedard et al. 2001). The 12-item version has also been shown to have good discriminatory ability in determining caregivers with low and high burden in different contexts (Higginson et al. 2010).

Other measures

The level of dependence of the elderly care recipients on the caregivers was assessed using the Katz ADL (Wallace and Shelkey 2007). The Katz ADL measures independence of function in six domains – bathing, dressing, toilet, transfer, continence and feeding. The caregivers in this study described the level of dependence of the elderly care recipients using the scores in the Katz ADL. The GHQ-12 was used to assess the level of psychological distress among the informal caregivers (Craig Jackson 2007) while the MCTS was used to determine the perpetration of physical or psychological elder abuse by the caregivers (Cooper et al. 2009, 2008).

The instrument was translated into Yoruba, the local language using the iterative back-translation method and administered by health workers in the primary health care centres of the selected communities who had been trained for this purpose.

Data analysis

The data obtained were analysed using SPSS version 22. Exploratory factor analysis of the burden data was conducted using principal components analysis and varimax rotation to determine the factorial structure in the data. The adequacy of the sample was evaluated using the Bartlett test of sphericity and the Kaiser-Meyer-Olkin (KMO) test. Internal consistency was determined with the Cronbach’s alpha where a Cronbach’s α of at least 0.70 was accepted as demonstrating good internal consistency (Bedard et al. 2001; Chattat et al. 2011). The instrument reliability was also tested with the Guttman split-half correlation, a correlation coefficient calculated between the scores on two halves of the test. A high value >0.70 means good reliability (Chattat et al. 2011). Consistency of the items in the scale was assessed using item total correlations. Construct validity was assessed using Spearman’s correlations between the ZBI and the GHQ-12, the Katz ADL and the MCTS for elder abuse perpetration.

Limitation

Most studies found in literature have reviewed the 22-item version of the ZBI in different settings. However, the preference for the short version of the ZBI in this study was for easier administration in community settings where caregivers are likely to be less responsive when the tool is lengthy. This study was therefore unable to compare the mean ZBI scores with those derived from previous validity tests of the ZBI.

RESULTS

Sociodemographic information

Data obtained from 80informal caregivers were analyzed. All the caregivers were unpaid relatives of the elderly persons to whom they provided care. The mean age of the respondents was 35.8±9.7 years with 50 (62.5%) in the 21–39-year age bracket (Table 1). There were more females (57.5%) than males and the most common occupation was trading (51.2%).

Table 1.

Sociodemographic characteristics of the study participants

Variable Frequency (%) N=80
Age (years)
≤ 20 3 (3.8)
21–39 50 (62.5)
≥ 40 27 (33.7)
Sex
Male 34 (42.5)
Female 46 (57.5)
Marital status
Single 21 (26.3)
Married 59 (73.7)
Occupation
Farming 8 (10.0)
Trading 41 (51.2)
Artisan 18 (22.5
Civil servant 8 (10.0)
Unemployed 5 (6.3)
Tribe
Yoruba 77 (96.2)
Others 3 (3.8)
Level of education
No formal 9 (11.32
Completed primary 18 (22.5)
Completed secondary 37 (46.3)
Completed tertiary 16 (20.0)
Religion
Christianity 46 (57.5)
Islam 33 (41.3)
Traditional 1 (1.2)
Open in a new tab

Construct validity

The correlation of the ZBI with other instruments is shown in Table 3. Spearman’s correlation (rs) showed a significant positive correlation between the ZBI scores and GHQ-12 (rs = 0.44, p = <0.001). There was also a positive correlation with the MCTS for elder abuse perpetration scale (rs = 0.43, p = <0.001). On the other hand, the Spearman’s correlation between the ZBI scores and Katz assessment of ADL for the care recipients was a significant negative correlation (rs = −0.50, p <0.001).

Table 3.

Correlation of ZBI with other tools

Measure tools N=80 Correlation with total ZBI scores p value
The General Health Questionnaire (GHQ-12) 0.440 <0.001
Katz assessment of functional Activities of Daily Living (ADL) −0.501 <0.001
Modified Conflict Tactics Scale for Elder Abuse perpetration (MCTS) 0.427 <0.001
Open in a new tab

Reliability

The reliability analysis gave a Cronbach’s α of 0.90 and a Guttman split-half correlation coefficient of 0.84. The internal consistency of the scale was not improved by withdrawal of any of the items (Table 2). The total scores of the individual items in the ZBI ranged from 0.00 to 41.00 while the mean scores ranged from 0.36 to 1.08 and the corrected item-total correlation was positive (>0.50) for all the items in the ZBI.

Table 2.

Mean score for items and item-total (corrected) correlation for ZBI reliability analysis

Item description Mean ± SD Corrected item total correlation Cronbach’s α if deleted
1. Not enough time for myself 0.85±1.12 .551 .885
2. Stressed for caring & other responsibilities 0.81±1.03 .583 .883
3. Feel angry 0.38±0.89 .545 .885
4. Negative effect on relationships 0.36±0.75 .709 .879
5. Feel strained 0.33±0.84 .623 .881
6. Health has suffered 0.58±1.07 .726 .875
7. Lack of privacy 0.44±0.91 .579 .883
8. Lack of social life 0.36±0.72 .698 .880
9. Lost control of life 0.38±0.91 .738 .875
10. Uncertain about what to do 0.50±1.04 .625 .880
11. Should do more 1.08±1.36 .478 .893
12. Could do a better job caring 1.08±1.19 .555 .885
Open in a new tab

Factor analysis

The Bartlett Test of Sphericity was statistically significant (χ2 = 516.08, df = 66, p < 0.001) while the Kaiser-Meyer-Olkin measure of sample adequacy was 0.831, which was an excellent justification for the factor analysis. Three factors with eigenvalues greater than 1.0were extracted on the exploratory factor analysis comprising all 12 items and these accounted for 68%.0 of the total item variance (Table 4). Seven items (1, 2, 4, 5, 6, 9 and 10) loaded on the first factor, which accounted for 48.5% of the total item variance while the second (items 8, 11 and 12) and third (items 3 and 7) factors accounted for 10.7% and 8.8% of the total variance respectively.

Table 4.

Factor loadings from exploratory factor analysis for ZBI

Item No Item description Factor loadings
Subtheme 1
1 Not enough time for myself 0.771
2 Stressed for caring & other responsibilities 0.880
4 Negative effect on relationships 0.539
5 Feel strained 0.657
6 Health has suffered 0.738
9 Lost control of life 0.592
10 Uncertain about what to do 0.617
Subtheme 2
8 Lack of social life 0.519
11 Should do more 0.851
12 Could do a better job caring 0.786
Subtheme 3
3 Feel angry 0.858
7 Lack of privacy 0.856
Open in a new tab

DISCUSSION

The results of this study demonstrate strong construct validity of the tool. There was a good correlation between the ZBI and GHQ-12 scores in this study. Strong correlation between GHQ-12 and GHQ-28 scores and the 22-item ZBI has been reported in previous studies (Seng et al. 2010; Chattat et al. 2011). Other studies have also shown correlation between burden scores on the ZBI and emotional or psychological distress in the caregivers (Braun et al. 2010; Scazufca 2002; Hébert, Bravo, and Préville 2000). The correlation of the 12-item ZBI with the GHQ is consistent with these findings making it an appropriate format for the assessment of caregiver burden in relation with psychological distress in instances where the length of the full ZBI may be a problem. The relationship between subjective caregiver burden and psychological distress can be explored by combining the tools.

The Katz ADL and the MCTS also showed good correlation with the 12-item ZBI. Although the ZBI has been found to correlate well with level of independence among the care recipients (Bedard et al. 2001), this is the first time the 12-item ZBI has been correlated with the Katz ADL. The significant negative correlation of the ZBI with the Katz ADL implies an inverse relationship between caregiver burden and independence in the care recipient. One can therefore infer that caregivers whose care recipients are independent are likely to have lower ZBI scores. When used in combination with the Katz ADL, associations between the ZBI scores and the care recipient’s independence for functional activities of daily living can be explored. The MCTS has been validated in previous studies and shown to be acceptable for assessing elder abuse by their caregivers (Cooper et al. 2008). This study shows good correlation of the MCTS with the 12-item ZBI making it an ideal tool for testing the association between caregiver burden and elder abuse perpetration. Thus, this short form of the ZBI is a versatile tool that can be used in conjunction with other instruments in the assessment of caregiver burden in relation with other factors affecting the caregiving process.

The results of this study also show that the 12-item ZBI has good internal consistency with a high Cronbach α (0.90) and split-half correlation coefficient (0.84). This implies that the tool can be reliably used in the study population. The Cronbach α in this study was slightly higher than that derived by Bédard (0.88) for the same version which was used among caregivers of elders with cognitive impairment (Bedard et al. 2001). The value obtained in this study was within the same range as that derived for the full ZBI in studies conducted in Brazil (0.87) (Scazufca 2002), Singapore (0.93) (Seng et al. 2010), Italy (0.90) (Chattat et al. 2011), Japan (0.88) (Hirono, Kobayashi, and Mori 1998) and Germany (0.92) (Braun et al. 2010). Thus, the 12-item ZBI compares favorably with the full version in terms of its reliability.

In conclusion, the 12-item ZBI is a valid and reliable tool for assessing burden in informal settings among caregivers of elderly persons without cognitive impairment or any known medical illness. The tool also has good correlation with the 12-item General Health Questionnaire, the Katz Index of Independence in Activities of Daily Living and the Modified Conflicts Tactics Scale for elder abuse when administered to the caregivers of elderly persons. These instruments have been used in assessing factors associated with caregiver burden.

Acknowledgments

I acknowledge MEPIN for providing me with hand on skill in manuscript writing. Data analysis and writing of this paper was supported by the University of Ibadan Medical Education Partnership Initiative Junior Faculty Training Programme (UI-MEPI-J) project funded by Fogarty International Center, National Institute of Health under Award Number D43TW010140. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding organizations.

References

  1. Ajomale Olayinka. Country Report: Ageing in Nigeria – Current State, Social and Economic Implications. Sociology of Aging Oxford. 2007a:15–20. [Google Scholar]
  2. Ajomale Olayinka. Elder Abuse; The Nigerian Experience 2007b [Google Scholar]
  3. Ani Judith Ifunanya. Care and Support for the Elderly in Nigeria: A Review. The Nigerian Journal of Sociology and Anthropology. 2014;12(1):9–27. [Google Scholar]
  4. Ballesteros Javier, Santos Borja, González-Fraile Eduardo, Muñoz-Hermoso Paula, Domínguez-Panchón Ana I, Martín-Carrasco Manuel. Unidimensional 12-Item Zarit Caregiver Burden Interview for the Assessment of Dementia Caregivers’ Burden Obtained by Item Response Theory. Value in Health. 2012;15(8):1141–47. doi: 10.1016/j.jval.2012.07.005. [DOI] [PubMed] [Google Scholar]
  5. Beach Scott R, Schulz à Richard, Williamson Gail M, Miller L Stephen, Weiner Myron F, Lance Charles E. Risk Factors for Potentially Harmful Informal Caregiver Behavior. Journal of the American Geriatrics Society. 2005;53(2):255–61. doi: 10.1111/j.1532-5415.2005.53111.x. [DOI] [PubMed] [Google Scholar]
  6. Beach Scott R, Schulz Richard, Castle Nicholas G, Rosen Jules. Financial Exploitation and Psychological Mistreatment among Older Adults: Differences between African Americans and Non-African Americans in a Population-Based Survey. The Gerontologist. 2010 doi: 10.1093/geront/gnq053. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Bedard M, Molloy DW, Squire L, Dubois S, Lever JA, O’Donnell M. The Zarit Burden Interview: A New Short Version and Screening Version. The Gerontologist. 2001;41(5):652–57. doi: 10.1093/geront/41.5.652. [DOI] [PubMed] [Google Scholar]
  8. Brandl Bonnie, Raymond Jane A. Policy Implications of Recognizing That Caregiver Stress Is Not the Primary Cause of Elder Abuse. Journal of the American Society on Aging. 2012;36(3):32–39. [Google Scholar]
  9. Braun Melanie, Scholz Urte, Hornung Rainer, Martin Mike. The Burden of Spousal Caregiving: A Preliminary Psychometric Evaluation of the German Version of the Zarit Burden Interview. Aging & Mental Health. 2010;14(2):159–67. doi: 10.1080/13607860802459781. [DOI] [PubMed] [Google Scholar]
  10. Caciula Ioana, Livingston Gill, Caciula Rodica, Cooper Claudia. Recognition of Elder Abuse by Home Care Workers and Older People in Romania. International Psychogeriatircs. 2010;22(3):403–8. doi: 10.1017/S104161020999161X. [DOI] [PubMed] [Google Scholar]
  11. Chattat Rabih, Cortesi Valeria, Izzicupo Fabio, Letizia Del Re Maria, Sgarbi Cinzia, Fabbo Andrea, Bergonzini Elisa. The Italian Version of the Zarit Burden Interview: A Validation Study. International Psychogeriatrics. 2011;23(5):797–805. doi: 10.1017/S1041610210002218. [DOI] [PubMed] [Google Scholar]
  12. Cooper Claudia, Blanchard Martin, Selwood Amber, Walker Zuzana, Livingston Gill. Family Carers’ Distress and Abusive Behaviour: Longitudinal Study. The British Journal of Psychiatry. 2010;196(6):480–85. doi: 10.1192/bjp.bp.109.071811. [DOI] [PubMed] [Google Scholar]
  13. Cooper Claudia, Manela Monica, Katona Cornelius, Livingston Gill. Screening for Elder Abuse in Dementia in the LASER-AD Study: Prevalence, Correlates and Validation of Instruments. International Journal of Geriatric Psychiatry. 2008;23(3):283–88. doi: 10.1002/gps.1875. [DOI] [PubMed] [Google Scholar]
  14. Cooper Claudia, Maxmin Kate, Selwood Amber, Blanchard Martin, Livingston Gill. The Sensitivity and Specificity of the Modified Conflict Tactics Scale for Detecting Clinically Significant Elder Abuse. International Psychogeriatrics/IPA. 2009;21(4):774–78. doi: 10.1017/S1041610209009387. [DOI] [PubMed] [Google Scholar]
  15. Craig Jackson. The General Health Questionnaire. Occupational Medicine. 2007;57(79) doi: 10.1093/occmed/kql169. 2007. [DOI] [Google Scholar]
  16. Flynn Longmire Crystal V, Knight Bob G. Confirmatory Factor Analysis of a Brief Version of the Zarit Burden Interview in Black and White Dementia Caregivers. The Gerontologist. 2011;51(4):453–62. doi: 10.1093/geront/gnr011. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Gureje O. Reliability and the Factor Structure of the Yoruba Version of the 12 Item General Health Questionnaire. Acta Psychiatr Scand. 1991;84:126–29. doi: 10.1111/j.1600-0447.1991.tb03115.x. [DOI] [PubMed] [Google Scholar]
  18. Gureje Oye, Ogunniyi Adesola, Kola Lola, Afolabi Ebenezer. Functional Disability among Elderly Nigerians: Results from the Ibadan Study of Ageing. Journal of the American Geriatrics Society. 2006;54(11):1784–89. doi: 10.1111/j.1532-5415.2006.00944.x.Functional. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Hébert Réjean, Bravo Gina, Préville Michel. Canadian Journal on Aging/La Revue Canadienne Du Vieillissement. 4. Vol. 19. Cambridge University Press; 2000. Reliability, Validity and Reference Values of the Zarit Burden Interview for Assessing Informal Caregivers of Community-Dwelling Older Persons with Dementia; pp. 494–507. [DOI] [Google Scholar]
  20. Higginson Irene J, Gao Wei, Jackson Diana, Murray Joanna, Harding Richard. Journal of Clinical Epidemiology. 5. Vol. 63. Elsevier Inc; 2010. Short-Form Zarit Caregiver Burden Interviews Were Valid in Advanced Conditions; pp. 535–42. [DOI] [PubMed] [Google Scholar]
  21. Hirono N, Kobayashi H, Mori E. Caregiver Burden in Dementia: Evaluation with a Japanese Version of the Zarit Caregiver Burden Interview. Nō to Shinkei = Brain and Nerve. 1998;50(6):561–67. [PubMed] [Google Scholar]
  22. Katz Sidney, Ford Amasa B, Moskowitz Roland W, Jackson Beverly A, Jaffe Marjorie W. Studies of Illness in the Aged. The Index of ADL: A Standardized Measure of Biological and Psychosocial Function. JAMA. 1963;185(12):914–19. doi: 10.1001/jama.1963.03060120024016. [DOI] [PubMed] [Google Scholar]
  23. Mudiare Edirin, Ukiri Patience. Abuse of the Aged in Nigeria : Elders Also Cry. International Journal of Contemporary Research. 2013;3(9):79–87. [Google Scholar]
  24. Scazufca Marcia. Brazilian Version of the Burden Interview Scale for the Assessment of Burden of Care in Carers of People with Mental Illnesses. Revista Brasileira de Psiquiatria. 2002;24(1):10–15. doi: 10.1590/S1516-44462002000100006. [DOI] [Google Scholar]
  25. Seng Boon Kheng, Luo Nan, Ng Wai Yee, Lim June, Chionh Hui Ling, Goh Jenny, Yap Philip. Validity and Reliability of the Zarit Burden Interview in Assessing Caregiving Burden. Annals of the Academy of Medicine Singapore. 2010;39(10):759–63. [PubMed] [Google Scholar]
  26. Sijuwade Phillip O. Elderly Care by Family Members: Abandonment, Abuse and Neglect. The Social Sciences. 2008;3(8):542–47. [Google Scholar]
  27. Steadman Pamela Lea, Tremont Geoffrey, Duncan Davis Jennifer. Premorbid Relationship Satisfaction and Caregiver Burden in Dementia Caregivers. Journal of Geriatric Psychiatry and Neurology. 2007;20(2):115–19. doi: 10.1177/0891988706298624. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Uwakwe R, Modebe I. Disability and Caregiving in Old Age in a Nigerian Community. Nigerian Journal of Clinical Practice. 2007;10(1):58–65. [PubMed] [Google Scholar]
  29. Wallace Meredith, Shelkey Mary. Katz Index of Independence in Activities of Daily Living (ADL) Try This: Best Practices in Nursing Care to Older Adults. 2007;(2):21–22. [Google Scholar]
  30. Wang Gang, Cheng QI, Wang Ying, Deng Yu-lei, Ren Ru-jing, Xu Wei, Zeng Jie, Bai Li, Chen Sheng-di. The Metric Properties of Zarit Caregiver Burden Scale: Validation Study of a Chinese Version. Alzheimer Disease and Associated Disorders. 2008;22(4):321–26. doi: 10.1097/WAD.0b013e3181902334. [DOI] [PubMed] [Google Scholar]

RESOURCES