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Caregiver burden in mild cognitive impairment a
Matt Paradise , Donna McCade , Ian B. Hickie , Keri Diamond , Simon J.G. Lewis & Sharon L. Naismith
Brain & Mind Research Institute, University of Sydney, Camperdown, Australia Published online: 28 May 2014.
Click for updates To cite this article: Matt Paradise, Donna McCade, Ian B. Hickie, Keri Diamond, Simon J.G. Lewis & Sharon L. Naismith (2015) Caregiver burden in mild cognitive impairment, Aging & Mental Health, 19:1, 72-78, DOI: 10.1080/13607863.2014.915922 To link to this article: http://dx.doi.org/10.1080/13607863.2014.915922
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Aging & Mental Health, 2015 Vol. 19, No. 1, 7278, http://dx.doi.org/10.1080/13607863.2014.915922
Caregiver burden in mild cognitive impairment Matt Paradise*, Donna McCade, Ian B. Hickie, Keri Diamond, Simon J.G. Lewis and Sharon L. Naismith Brain & Mind Research Institute, University of Sydney, Camperdown, Australia
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(Received 26 November 2013; accepted 13 April 2014) Objectives: We aimed to compare the rates of burden amongst caregivers of participants with mild cognitive impairment (MCI), compared to a control group. We also aimed to identify factors in both the caregiver and patient that are associated with significant levels of burden. Method: This was a cross-sectional study. Sixty-four participants with MCI, 36 control-participants and their respective caregivers/informants were recruited to a university research clinic. The proportion of those who showed clinically significant levels of burden was determined by a Zarit Burden Interview score of >21. The associations of burden in MCIcaregivers were calculated in the following categories; participant characteristics (including depressive symptoms, cognition and informant ratings of cognitive and behavioural change); caregiver characteristics; and the caregiving context. Multivariate analyses were performed to examine the relative contribution of individual variables to burden amongst MCI-caregivers. Results: We found that 36% of MCI-caregivers reported clinically significant levels of burden, twice that of the control informant group. Participant behavioural problems contribute most to burden, with participant depression and possibly cognition also having a significant association. Conclusion: Caregiver burden is a considerable problem in MCI and shares some of the same characteristics as caregiver burden in dementia, namely a strong association with challenging behaviours in the patient. This has implications for further research and intervention studies. Keywords: mild cognitive impairment; caregivers; depression; burden
Introduction Extensive research has been undertaken regarding caregiver burden in dementia (Richardson, Lee, Berg-Weger, & Grossberg, 2013). Caregiver burden is not only associated with an adverse emotional state and psychiatric morbidity in the caregiver but has additional physical sequelae, financial and social consequences. Compared to non-caregivers, for example, caregivers are more likely to report worse health, utilize medical care more frequently and take psychotropic medication (Burns & Rabins, 2000; Etters, Goodall, & Harrison, 2008; Schulz & Martire, 2004). Caregiver burden also has deleterious consequences for the patient and is strongly associated with the need for institutionalization (Luppa, Luck, Brahler, Konig, & Riedel-Heller, 2008). Caregiver burden is common, with studies reporting that around 22% of caregivers experience clinical depression (Cuijpers, 2005), and some studies suggesting that up to 75% of caregivers experience significant depressive (Teri, 1994) and anxiety (Cooper, Balamurali, & Livingston, 2007) symptoms. Caregiver burden in dementia is associated with factors in three domains; patient characteristics, caregiver characteristics and the caregiving context (Burns & Rabins, 2000; Clyburn, Stones, Hadjistavropoulos, & Tuokko, 2000). With regard to patient characteristics, the frequency of behavioural problems in dementia has been identified as the strongest predictor of caregiver burden, more than the functional or cognitive impairments of the patient. Amongst caregiver characteristics, female caregivers and *Corresponding author. Email: [email protected]
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those with worse health are more likely to experience burden. Finally, research suggests that the caregiving experience is most difficult for spousal caregivers and that increased social support is important in mitigating caregiver burden (Joling et al., 2010). Comparatively however, the issue of caregiver burden in milder forms of cognitive impairment has been underresearched. Mild cognitive impairment (MCI) is a proposed interim stage between normal ageing and dementia, characterized by the presence of cognitive impairment in the context of essentially intact activities of daily living (Petersen et al., 1999). Since these original criteria were published however, studies have reported subtle impairments in functioning for up to two years before a diagnosis of dementia is made, as well as the presence of behavioural symptoms including irritability or depression (Gauthier et al., 2006). The prevalence of MCI is reported to be approximately 3%19% based on population-based epidemiological studies with approximately 10% of MCI cases converting to dementia each year (Gauthier et al., 2006). With an ageing population in the developed world, it is projected that the prevalence of MCI will rise. Seeher, Low, Reppermund, and Brodaty (2013) recently reviewed the published literature and reported data from 10 articles, representing nine distinct caregiving MCI cohorts. The studies were heterogeneous in nature and utilized several primary outcome measures, including depression, burden, stress and anxiety. There were several limitations to these papers, including lack of
Aging & Mental Health representativeness by reliance on only spousal caregivers, the lack of appropriate variables being entered into multivariate analyses and the lack of a control group in all but two studies (Muangpaisan, Intalapaporn, & Assantachai, 2008; Ready, Ott, & Grace, 2004). This paper therefore intends to expand the limited research in this field. The primary aim is to report the prevalence of significant levels of burden amongst caregivers of people with MCI, compared to informants of control-participants. Second, to identify which factors are associated with significant levels of burden based on findings from dementia research in three categories; patient characteristics, caregiver characteristics and the caregiving context.
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Methods Sixty-four participants with MCI and their caregivers were recruited from the Healthy Brain Ageing Clinic at the Brain and Mind Research Institute, University of Sydney. All participants were help-seeking to a specialist research clinic targeting healthy brain ageing and were reporting mood and/or cognitive symptoms. Participants were required to be aged 50 or above and to have adequate English proficiency for neuropsychological assessment. Exclusion criteria included: history of stroke, head injury with loss of consciousness for more than 30 minutes, neurological disorder, medical condition known to affect cognition (e.g., cancer), psychiatric disorder other than an affective disorder, mini-mental state examination (MMSE) score below 24 and/or diagnosis of dementia. Since the presence of a current full-threshold mood disorder is associated with cognitive decline (Naismith et al., 2003), individuals fulfilling the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) (American Psychiatric Association, 1994) criteria for major depressive disorder were also excluded. The choice of caregiver was determined by the participant, with the recommendation that the caregiver knew the participant well and was able and willing to fill in a questionnaire about the participant. These included spouses, family members and friends. Thirty-six control-participants and their significant others, to be called ‘informants’, were also recruited. These participants were cognitively intact individuals responding to adverts looking for controls as well as helpseeking individuals who were found on extensive testing not to fulfil diagnosis for MCI. Informants were chosen by control-participants in the same manner as caregivers were chosen by MCI-participants as above. Control-participants had the same assessment and battery of tests as MCI-participants and were also excluded if they had current DSM-IV diagnosed depression or any of the other exclusion criteria listed above. This study was approved by the University of Sydney Human Research Ethics Committee, and written informed consent was obtained from all participants and their caregivers/informants. MCI ratings were conducted by consensus of an old age psychiatrist and two clinical neuropsychologists. In
accordance with the Petersen et al. (1999) criteria, individuals were classified as having MCI if upon neuropsychological testing, they scored at least 1.5 standard deviations (SD) below their predicted level of intellectual functioning in at least one cognitive domain, while daily functioning remained largely intact. Daily functioning was assessed by a psychiatrist and neuropsychologist, with reference to additional caregiver-based interviews where warranted. All participants were rated on the Global Assessment of Functioning Scale (American Psychiatric Association, 1994) and obtained scores greater than 60, suggesting no greater than mild functional decline. MCI-participants were further classified as either amnestic or non-amnestic depending on whether their impairments affected the memory domain (Petersen & Morris, 2005). Note that the amnestic subtype was required to exhibit a memory deficit of the ‘hippocampaltype’ (i.e., memory storage impairment), as demonstrated by evidence of dysfunction on tests of delayed memory recall (i.e., not merely encoding deficits). Participant measures Demographic information including age, gender, and education was obtained. Severity of depressive symptoms was rated on the 17-item Hamilton Depression Rating Scale (HAM-D (Hamilton, 1960)). Physical health was recorded using the total score severity index of the Cumulative Illness Rating Scale, Geriatric Version (CIRS-G (Miller, 1991)). As described previously (Mowszowski et al., 2012), a neuropsychologist administered a battery of standardized tests to participants to assess cognition. For descriptive purposes, premorbid intelligence was estimated using the Wechsler Test of Adult Reading (Wechsler, 2001) and global cognitive functioning was measured using the MMSE (Folstein, Folstein, & McHugh, 1975). A measure of participant behaviour and function were obtained using the Cambridge Behavioural Inventory Revised (CBI-R (Wear, 2008)). The CBI-R is a 45-item questionnaire that was completed by the caregiver/informant and assesses changes in functional and behavioural domains including memory and orientation (eight items), everyday skills (five items), self-care (four items), abnormal behaviour (six items), mood (four items), beliefs (three items), eating habits (four items), sleep (two items), stereotypic and motor behaviours (four items) and motivation (five items). A total score was obtained by summing all domain scores. The frequency of symptoms present over the past month is rated on a scale from 0 to 4. Score 0 indicates no impairment; 1, a few times per month; 2, a few times per week; 3, a daily occurrence; and 4, constant occurrence. Caregiver/informant measures For the purposes of clarity and consistency, family members and friends who supported someone living with MCI were referred to as ‘caregivers’, although they may not
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have regarded themselves as such, or indeed fulfilled a caregiving role. This is consistent with the literature in MCI (Seeher et al., 2013) and dementia (Dean & Wilcock, 2012). The significant others of control-participants were referred to as ‘informants’. Caregivers and informants completed a questionnaire which included demographic information of age, gender, and education. If necessary, this was augmented by a phone call to obtain missing demographic details about the informant. Information about the nature of the relationship between the participant and caregiver/informant (i.e., spouse, relative, friend, or other) was obtained as well as information on whether the dyad lived together. The Hospital Anxiety and Depression Scale (HADS (Zigmond & Snaith, 1983)) was used to assess the caregiver/informant’s depressive and anxiety symptom severity. This 14-item Likert scale has seven items measuring anxiety and seven measuring depression. Each item is rated from 0 to 3, generating a total score between 0 and 21 for both anxiety and depression. Based on existing literature, a cut-off of 8 was used to identify borderline or significant cases of anxiety and/or depression (Bjelland, Dahl, Haug, & Neckelmann, 2002). The Zarit Burden Interview (ZBI (Zarit, Reever, & Bach-Peterson, 1980)) was the primary outcome measure of burden. This self-report questionnaire contains 22 questions with a Likert multiple choice response of the frequency of feelings, ranging from ‘Never’ (0), to ‘Nearly Always’ (4). A total score between 0 and 88 is generated. A score of 21 or greater was chosen to be clinically significant based on guidelines (Zarit & Zarit, 1987) and other papers in MCI (Bruce, McQuiggan, Williams, Westervelt, & Tremont, 2008). Statistical analyses All statistical analyses utilized the Statistical Package for the Social Sciences (IBM SPSS 20.0.0 for Windows, Chicago, IL, USA). Baseline characteristics for MCI-participants, control-participants, and their respective caregiver/ informants were obtained. Independent sample t-tests and chi-square tests were then performed to check for differences in characteristics between the MCI-participants and control-participants as well as between the two groups of caregiver/informants. Independent sample t-tests were used to compare the mean ZBI score for MCI-caregivers and control-informants. The proportion of individuals with clinically significant burden in each group was also reported, with chi-square testing the between-group differences. For the caregivers of MCI-participants, test of univariate association between mean ZBI score and participant characteristics, caregiver characteristics and caregiving context were then performed. For the dichotomous variables of participant gender, amnestic vs. non-amnestic MCI, caregiver/informant gender and whether the dyad co-habited, independent sample t-tests were used. For the categorical variables of participant educational level, caregiver/ informant educational level, and the relationship to the participant, analysis of variance (ANOVA) tests were used.
For continuous data, the participant’s age, clinician-rated participant depression (HAM-D), CBI data, and the informant’s age, both Pearson and Spearman correlation coefficients were used depending on the distribution of data. Assumptions of normality were based on visual inspection using histograms as well as KolmogorovSmirnov tests, with a p < 0.05 significance level chosen. Multivariate analyses were then performed to examine the relative contribution of individual variables to burden amongst MCI-informants. Significant variables at the p < 0.05 were entered simultaneously into a linear regression model. A sensitivity analysis was conducted with caregivers dichotomized into those who suffered significant informant stress (ZBI > 21) versus those who did not. The analyses described above were then repeated using caregiver/informant stress as a dichotomous rather than continuous outcome measure. Finally, HADS depressive and anxiety symptoms in the caregivers/informants were reported as both a mean score as well as a proportion of those who achieved borderline or significant caseness. The mean anxiety and depression scale scores were then correlated with burden. Results There was only minimal missing data. Two MCI-participants and one control-participant did not have an MMSE recorded. Age and education data was not provided by 13 MCI-informants and eight control-informants. One control-informant did not provide gender data and another control-informant did not provide CBI sleep and stereotypic subscales and thus CBI-Total. Characteristics of both the 64 MCI-participants and 36 control-participants and their respective caregiver/informants are reported in Table 1. There was a higher proportion of women in the control-participant group compared to the MCI-participant group (x2 ¼ 5.27, df ¼ 1, p ¼ 0.03) and as we would expect, a significantly reduced MMSE in the MCI-participant group compared to the control-participant group (t(88) ¼ 3.76; p < 0.001). There was no significant difference in the physical health (total CIRS-G score) between the MCI-participants and controlparticipants (t(97) ¼ 1.86; p ¼ 0.07). No other demographic information was significantly different between the two sets of groups. The primary outcome measure was mean ZBI score. The mean ZBI score for MCI-caregivers was 17.3 (SD 11.2; range 049) compared to the control-informants mean score of 11.6 (SD 1.1; range 045). This was a significant difference (t(98) ¼ 2.43, p ¼ 0.02). Twentythree of 64 MCI-caregivers (35.9%) reported clinically significant burden (ZBI > 21) compared with only 6 out of 36 control-informants (16.7%). This is a statistically significant difference (x2 ¼ 4.16, df ¼ 1, p ¼ 0.04). The univariate associations of participant and caregiver characteristics with burden in the 64 MCI-caregivers are reported in Table 2. The participants’ depression score (HAM-D) and their behavioural disturbance (CBI), either as a total score or 8 out of 10 subscales were associated
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Table 1. Characteristics of MCI and control-participants, and their caregivers/informants. Characteristic N Age in years, mean SD Female gender Education
MMSE, mean SD Relationship to participant
Did not complete high school Completed high school Completed higher study Partner/spouse
64 64.9 9.7
36 64.6 9.7
64 55.6 14.1
36 56.2 14.3
35 (54.7%) 17 (26.6%) 17 (26.6%) 30 (46.9%) 27.9 2.6
28 (77.8%) 13 (36.1%) 10 (27.8%) 13 (36.1%) 29.3 1.0
39 (61.9%) 11 (21.6%) 7 (13.7%) 33 (64.7%) 35 (54.7%)
20 (55.6%) 3 (10.7%) 5 (17.9%) 20 (71.4%) 22 (61.1%)
6 (9.4%) 20 (31.3%) 3 (4.7%) 45 (70.3%)
2 (5.6%) 12 (33.3%) 0 23 (63.9%)
Relative Friend Other Living with participant (yes)
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Notes: SD ¼ Standard deviation, MMSE ¼ Mini-mental state examination.
with greater burden in the informants of those looking after someone with MCI. Global cognition of the participant, as measured by the MMSE, just failed to achieve a significant association with burden (p ¼ 0.05). None of the other variables examined were associated with caregiver burden. These univariate results were then entered into a multivariate regression model (Table 3). The model included the depression score, total functional/behavioural disturbance and the MMSE as it trended towards significance with p ¼ 0.05. We found that total functional/behavioural disturbance score, measured by the CBI-R was the only factor independently associated with informant burden in MCI-informants. A further analysis was then performed with caregivers dichotomized into those who suffered significant informant stress (ZBI > 21) versus those who did not. Accordingly, the univariate results were very similar for these analyses, with depression and total functional/ behavioural disturbance, as reported in the CBI-R, being associated with the presence of informant burden. This was also the case for the MMSE. When the individual CBI-R subscales were examined, 7 of the 10 items were significant, with only memory problems, self-care, and abnormal beliefs not being associated with the presence of informant stress. Finally, depression and anxiety scores on the HADS were compared between the MCI-caregivers and controlinformant groups. There was no significant difference in the level of depressive symptoms reported by MCI-caregivers (M ¼ 4.27 4.34, n ¼ 55) and control-informants (M ¼ 3.48 3.25, n ¼ 33; t(86) ¼ 0.90, p ¼ 0.37). In contrast MCI-caregivers reported significantly greater anxiety (M ¼ 6.61 4.00, n ¼ 55) than control-informants (M ¼ 4.91 3.18, n ¼ 33; t(86) ¼ 2.09, p ¼ 0.04). Using a cut-off of eight to indicate caseness, 22/55 (40%) of MCI-caregivers experienced significant levels of anxiety and 10/55 (18%) of MCI-caregivers reported significant depression symptoms.
In MCI-caregivers, burden was significantly correlated with both the HADSanxiety scores (r ¼ 0.34; p ¼ 0.01) and HADSdepression scores (r ¼ 0.37; p ¼ 0.01). Discussion This study shows that burden is common in the caregivers of MCI-participants, with 36% reporting clinically significant levels of burden. This result was approximately double of that reported by the control group’s informants. When factors responsible for this burden were explored, depression reported by the MCI-participant, functional/ behavioural problems and possibly cognition were significant. On multivariate analysis, it was found that participant functional/behavioural problems as a whole contributed most to caregiver burden. We did not find that any of the caregiver characteristics measured (age, gender, education, and relationship to participant) or the caregiving context (whether the caregiver lived with the participant or not) were associated with the reported level of burden. Certain participant behaviours, namely problems with self-care and abnormal beliefs were not associated with informant stress. This is most likely because these behaviours were extremely rare in MCI, with the vast majority of caregivers in our study indicating that these problems had never occurred. The association of participant cognition and caregiver burden is less clear. Caregivers’ rating of the participant’s memory and orientation, as measured by the CBI-R, was associated with burden on univariate analysis, whereas clinician-scored cognition (i.e., MMSE) was not associated with burden. This may be due to the ceiling effect of the MMSE and its insensitivity for detecting the subtle cognitive changes of MCI (Nasreddine et al., 2005), compared to the sensitivity of the caregiver noticing even subtle cognitive changes (Tsang, Diamond, Mowszowski, Lewis, & Naismith, 2012). Our findings are consistent with the published literature. Garand, Dew, Eazor, DeKosky, and Reynolds (2005)
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Table 2. Univariate associations of participant, caregiver, and caregiving context characteristics with MCI-caregiver burden (mean ZBI score), n ¼ 64. Mean ZBI SD
r ¼ 0.08
17.9 11.2 16.8 11.3
t(62) ¼ 0.39
Did not complete high school Completed high school Completed higher study
17.2 12.0 19.8 11.2 15.9 10.8 17.3 10.7 17.3 11.6
Characteristic Participant characteristics
Age Gender MMSE Education
Depression (HAM-D) MCI subtype
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Amnestic Non-amnestic CBI-R (total)
rs ¼ 0.26 rs ¼ 0.40 rs ¼ 0.18 rs ¼ 0.55 rs ¼ 0.53 rs ¼ 0.22 rs ¼ 0.44 rs ¼ 0.33 rs ¼ 0.60 rs ¼ 0.44 r ¼ -0.05
Male Female Did not complete high school Completed high school Completed higher study Spouse
15.0 8.8 18.9 12.4 16.6 22.0 16.0 16.2
t(61) ¼ 1.33 N/A F(2,48) ¼ 0.93 F(3,60) ¼ 1.25
Relative Friend Other Yes No
19.2 20.0 8.0 17.1 10.6 17.7 12.6
t(62) ¼ 0.22
Age in years Gender Education
Relationship to participant
Living with participant
rs ¼ 0.52
Memory and orientation Everyday skills Self care Abnormal behavior Mood Beliefs Eating habits Sleep Stereotypic and motor behaviors Motivation Caregiver characteristics
rs ¼ 0.25 F(2,61) ¼ 0.65 r ¼ 0.30 t(62) ¼ 0.01
Notes: p < 0.05, p < 0.01, p < 0.001 SD ¼ Standard deviation, r ¼ Pearson’s correlation coefficient, t ¼ independent sample t test statistic, rs ¼ Spearman’s correlation coefficient, F ¼ F statistic ANOVA analysis. MMSE ¼ Mini-mental state examination, ZBI ¼ Zarit Burden Interview, HAM-D ¼ Hamilton Rating Scale for Depression and CBI-R ¼ Cambridge Behavioural Inventory Revised.
Table 3. Multivariate linear regression analysis; associations with burden in MCI-caregivers, n ¼ 61. Unstandardized coefficients Predictor variable MMSE score Depression (HAM-D) Functional/behavioural problems (CBI-R total)
0.15 0.65 0.29
0.55 0.33 0.06
0.04 0.23 0.55
Notes: p < 0.05, p < 0.01, p < 0.001. MMSE ¼ Mini-mental state examination, HAM-D ¼ Hamilton Rating Scale for Depression and CBI-R ¼ Cambridge Behavioural Inventory Revised.
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Aging & Mental Health interviewed the spouses of 27 participants recently diagnosed with MCI and reported that even at an early stage of cognitive impairment, spouses did have to take on additional caring responsibilities. Bruce et al. (2008) assessed 51 MCI patientcaregiver dyads and using the ZBI reported a similar figure of more than 30% (16 of 51 participants) of caregivers having clinically significant burden. They also reported similar factors were associated with burden included caregiver reports of more behavioural, memory and depressive symptoms, and the patient’s report of depression and cognitive difficulties. Burden was not associated with any of the neuropsychological measures tested. The study did not include measures of caregiver psychological distress or have a control group but did find the duration of cognitive symptoms to be a significant factor. The relationship between caregiver burden and depression is complex and to some extent multidirectional (Pearlin, Mullan, Semple, & Skaff, 1990). Clyburn et al. (2000) examined the nature of the association using structural equation modelling of four proposed mechanisms and found that in their study of Alzheimer’s disease and caregiver stress, a model where burden mediated depression produced the best fit. Accordingly, we found that caregiver burden was highly associated with both depressive and anxiety sub-scores on the HAD Scale. There has also been qualitative work into the MCIcaregiver experience (Adams, 2006; Blieszner & Roberto, 2010; Blieszner, Roberto, Wilcox, Barham, & Winston, 2007; Lu & Haase, 2009). A range of negative emotions are common including frustration, guilt and anger. The changing nature of the relationship between the dyad and the greater emphasis on caregiving, with a reduced level of intimacy and communication was frequently discussed. The experience of caring for someone with MCI may present different challenges and sources of burden when compared to caring for someone with diagnosed dementia. There is a much greater degree of prognostic uncertainty and generally, the caregivers will be at an early stage in their caregiving position and may have had less time to adjust to the role (Dean & Wilcock, 2012). There are several limitations to this study. Although this is one of the largest quantitative studies of caregiver burden in MCI to date, it is still relatively small, with just 64 MCI-caregivers. It is therefore liable to potential type II errors due to a lack of power. With greater numbers, certain factors, such as participant cognition may have achieved a statistically significant association with caregiver burden. Greater numbers would have also allowed for examination of the individual types of functional/ behavioural problems, to determine their relative contribution to informant burden. This was a cross-sectional study, so we cannot draw any inferences about the direction of causality between burden and anxiety and depressive symptoms. We also only had limited information about the history of our caregiver/informants and are thus unable to quantify the numbers of those who may have had pre-existing mental health problems, which may have had an impact on perceived burden. Equally, although the CBI-R measures change in the participant’s functional
and behavioural domains, we did not have a measure of the degree of caregiving responsibility, which would be useful to know as a possible contributor to burden. Finally, our cohort may not be a representative sample as all participants were seen in a university research clinic. The educational achievement in our cohort may be a reflection of this as well as a self-selection bias in those participants volunteering to take part in research studies. There is increasing recognition that there may be positive aspects of caregiving in MCI and this is something that would be valuable to explore in future studies (Werner, 2012). Our results suggest that burden is a considerable problem in MCI. Although it does not appear to be as prevalent as in dementia, caregiver burden in MCI shares some of the same characteristics, such as a strong association with challenging behaviours. Given that over half of participants with MCI will develop dementia within five years (Gauthier et al., 2006), the identification of burden early may allow timely intervention studies. These can hopefully prevent or reduce burden, with all it deleterious consequences for both patient and caregiver. To the best of our knowledge, only one such intervention study has been conducted, a cognitive behavioural therapy-based approach for both the patient with MCI and his/her caregiver. This intervention did not improve caregiver burden in their study, which may have been a reflection of the study size (JoostenWeyn Banningh, 2012). Future research should therefore involve further intervention studies as well as large prospective studies to allow detailed investigation of the etiology of caregiver burden and its relationship with anxiety and depression. Acknowledgements The authors would like to thank the participants and informants who participated in this study. We also gratefully acknowledge the contributions of Loren Mowzowski, Dr Zoe Terpening and Dr Louisa Norrie for their assistance with data collection.
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