Caregiver Burden and Depression in Mild Cognitive Impairment

Abstract

Little is known about contributors to burden and depression in caregivers of patients with mild cognitive impairment (MCI) even though these patients experience cognitive, emotional, and behavioral changes. We examined caregiver burden and depression in 43 caregivers for patients with MCI as well as their associations with patients’ neuropsychological status and behavioral symptoms. Almost 30% of caregivers reported clinically significant burden, whereas <5% reported significant depression. Increased caregiver burden was associated with greater disinhibited behaviors by patients, whereas increased caregiver depressive symptoms were associated with greater disinhibited behaviors as well as instrumental activity of daily living (ADL) impairments. Caregiver burden and depression were not associated with patients’ neuropsychological performance. Results suggest these caregivers would benefit from interventions addressing both practical methods to provide ADL assistance and behavioral methods to address inappropriate behaviors in patients in the predementia stages.

Keywords

caregiver burden caregiver depression mild cognitive impairment

Many older adults with cognitive impairments are cared for at home, and providing care can have significant consequences for caregivers. Dementia caregivers have poorer overall physical health, increased rates of emotional distress, increased utilization of health services, and higher mortality risk than noncaregiving individuals (Adams, Smyth, & McClendon, 2005; Baumgarten et al., 1992; Schulz & Beach, 1999; Sorensen, Duberstein, Gill, & Pinquart, 2006; Stevenson, 1990). Furthermore, as many as 50% of dementia caregivers experience caregiver burden, and frequent behavioral problems in dementia patients are associated with heightened caregiver burden (Davis & Tremont, 2007; Mohamed, Rosenheck, Lyketsos, & Schneider, 2010; Rymer et al., 2002).

However, little is known about the contributions to depression and burden in caregivers of patients with mild cognitive impairment (MCI), even though these patients experience cognitive, emotional, and behavioral changes. Lu et al. (2007) found 24.6% of MCI caregivers reported clinically significant depression. The odds of being depressed were significantly higher in younger, nonspousal caregivers with less education who cared for patients with lower levels of daily function, as well as in caregivers who perceived greater relational deprivation. However, neither did this study examine the presence of subclinical depression in caregivers nor did it use detailed measures of patients’ cognition. Blieszner and Roberto (2009) found increased MCI caregiver depressive symptoms were associated with poorer caregiver physical health, less caregiver knowledge about dementia, increased caregiver burden, and increased patient behavioral problems. However, they did not examine the types of behavioral problems leading to increased depression.

To date, only three studies have examined caregiver burden within the MCI population. In a series of interviews with 27 spouses of MCI patients, caregivers reported elevated levels of burden and burden was associated with depression and anxiety (Garand, Dew, Eazor, DeKosky, & Reynolds, 2005). However, this study was limited by its small sample size and predominantly female caregiver sample.

Caregiver burden was significantly correlated with patients’ MMSE scores, functional status, total caregiving hours, and neuropsychiatric symptoms in a mixed sample of patients diagnosed with MCI and AD (Gallagher et al., 2011). In a subsample of patients with milder impairment (MMSE > 20), only functional impairment emerged as a significant predictor of burden. Unfortunately, only 17% of patients had an MCI diagnosis, limiting the applicability of these findings to the MCI population.

In a retrospective chart review of 51 MCI patients, more than 30% of caregivers reported clinically significant burden (Bruce, McQuiggan, Williams, Westervelt, & Tremont, 2008). Increased caregiver burden was associated with a longer course of cognitive symptoms, patient reports of worse depression and greater cognitive difficulties, and caregiver reports of increased patient behavior, mood, and memory problems. Burden was not associated with patients’ cognition. However, this study did not include measures of caregivers’ emotional well-being (e.g., depression) and also did not examine the specific types of behavioral problems contributing to increased caregiver burden.

The purpose of this study was to cross-validate the findings of MCI caregiver burden in a new sample and examine different predictors of caregiver burden. We sought to explore the relationships between caregiver burden and depression in MCI and examine the associations with patients’ neuropsychological status and specific behavioral symptoms.

Method

Participants

This retrospective review included 43 patients (32 female) referred for a neuropsychological evaluation and diagnosed with amnestic or amnestic-plus MCI consistent with Petersen’s criteria (Petersen, 2004). All patients scored >1.5 standard deviations (SD) below the population mean on at least 1 neuropsychological test, although most were impaired on at least 1 additional measure. Patients were excluded if they had a history of traumatic brain injury, stroke, severe psychiatric illness, other neurological illnesses (e.g., seizure), drug/alcohol abuse, or developmental disability. All patients brought caregivers to the evaluation who participated in the clinical interview and completed questionnaires measuring their mood and perceived burden as well as patients’ functional impairment and behavioral problems. Caregiver reports were primarily completed by patients’ spouses (n = 24) and adult children (n = 16), with the remaining 3 caregivers identifying as friends or other family members. Sixty-five percent of caregivers were female, and 63% lived with the patient. This study was approved by the institutional review board.

Measures

Patient cognition

All participants completed a comprehensive neuropsychological evaluation assessing multiple domains which was administered according to standardized procedures. Composite indices for each domain were created by combining z scores based on the sample mean and standard deviation. Attention was measured with the Trail Making Test Part A (Reitan, 1958) and Digit Span forward subtest from the Wechsler Adult Intelligence Scales–III (Wechsler, 1997). The executive function domain was composed of the Trail Making Test Part B (Reitan, 1958) and the Controlled Oral Word Association (COWA) Test (Benton & Hamsher, 1989). Language was measured with the Boston Naming Test (Kaplan, Goodglass, & Weintraub, 1983) and Animal Fluency Test (Goodglass & Kaplan, 1983). Visuospatial skills were assessed with the Judgment of Line Orientation (Benton, Hamsher, Varney, & Spreen, 1983) and the Rey-Osterrieth Complex Figure Copy (Stern et al., 1999). The learning domain was composed of Hopkins Verbal Learning Test–Revised (HVLT-R; Brandt & Benedict, 2001) and Brief Visuospatial Memory Test–Revised (BVMT-R; Benedict, 1997) total learning scores. Delayed recall was assessed with the HVLT-R and BVMT-R delayed recall scores. For all indices, higher z scores indicate better performance.

Patient depression

The Beck Depression Inventory (BDI-II; Beck, Steer, & Brown, 1996) measured patients’ depressive symptoms. This 21-item self-report questionnaire measures affective, cognitive, and vegetative symptoms of depression, with greater scores indicating higher levels of depression. High internal consistency (α = .86) was observed in a sample of older adults (Segal, Coolidge, Cahill, & O’Riley, 2008).

Patient behavioral disturbance

Frontal systems behavior change was measured with the Frontal Systems Behavior Scale (FrSBe; Grace & Malloy, 2001). This 46-item scale is completed by the caregiver and measures behaviors associated with frontal systems dysfunction. The measure yields three subscale scores, apathy, disinhibition, and executive dysfunction, as well as a total score. Strong internal consistency has been observed for the 3 subscales in both healthy and neurological samples (α = .78-.91; Grace & Malloy, 2001).

Patient activities of daily living (ADLs)

Caregivers completed the Lawton-Brody Activities of Daily Living Questionnaire (Lawton & Brody, 1969), which measures patients’ degree of independence in basic (e.g., grooming, eating) and instrumental (e.g., medication and financial management) ADLs. Higher scores reflect greater functional independence. Good correlations have been demonstrated between the Lawton-Brody scale and other ADL measures (Lawton & Brody, 1969).

Caregiver burden

The 22-item Zarit Burden Interview (ZBI; Zarit, Reever, & Bach-Peterson, 1980), a self-report measure of perceived burden, assessed caregiver burden. Higher scores indicate higher levels of burden. High internal consistency (α = .92) was shown in a sample of informal dementia caregivers participating in the Canadian Study of Health and Aging (Herbert, Bravo, & Preville, 2000).

Caregiver depression

The Center for Epidemiologic Studies Depression Scale (CES-D; Radloff, 1977) measured caregivers’ depressive symptoms. This 20-item self-report measure assesses the extent to which caregivers experienced various symptoms of depression during the past week. Higher scores indicate higher levels of depression. Good sensitivity and specificity using a cutoff score of 16, as well as high internal consistency (α = .82), have been demonstrated in a sample of older adults (Lewinson, Seeley, Roberts, & Allen, 1997).

Statistical Analyses

Nonparametric Spearman correlational analyses examined relationships between caregivers’ perceived burden and mood and patients’ neuropsychological composite scores, frontal systems behavioral problems, and ADLs. Forward stepwise linear multiple regressions identified significant predictors of caregiver burden and depression. For each outcome variable, all bivariate significant predictors were candidates to enter the multiple regression equation. A candidate predictor variable could enter and remain in the multivariate equation if the p value associated with its multivariate regression coefficient was ≤.05. Analyses were performed using SPSS 12.0 [Statistical Package for the Social Sciences (SPSS), 2003].

Results

Demographic and clinical information can be found in Tables 1 and 2. Of the caregivers, 27.9% reported clinically significant burden (ZBI ≥ 21). Caregiver burden was not associated with patient age, gender, or education and was also not related to caregiver age or gender. No relationship between caregiver burden and whether patients lived with their caregiver or independently was observed. In contrast to almost 30% of caregivers reporting significant burden, only 2 caregivers reported clinically significant depression (CES-D ≥ 16). Caregiver depressive symptoms were positively correlated with patient age (r = .33, p < .05) but were not associated with patient gender or education, caregiver age or gender, or whether the caregiver was living with the patient.

Table 1.

Demographic Characteristics.

	M	SD	Range
Patient age	75.86	6.27	65-89
Patient education	13.21	3.36	7-20
Caregiver age	63.33	13.25	42-88
Caregiver education	14.86	2.33	12-20
ZBI	16.00	10.06	2-38
CESD	6.44	6.07	0-27
FrSBe
Apathy	28.72	8.14	16-44
Disinhibition	21.12	6.40	14-37
Executive dysfunction	37.47	11.05	17-63
Total	87.30	22.99	50-136
Lawton-Brody
Basic ADLs	11.68	0.61	10-12
Instrumental ADLs	13.78	2.54	7-16
Total	25.46	2.99	17-28

Note: ZBI = Zarit Burden Interview; CESD = Center for Epidemiological Studies Depression Scale; FrSBe = Frontal Systems Behavior Scale; ADL = activities of daily living. N = 43.

Table 2.

MCI Patients’ Neuropsychological Test Results.

	M	SD	Range
MMSE	26.07	2.27	20-30
WAIS-III Digit Span Forward	8.74	1.84	5-13
Trail Making Test A (sec)	52.21	24.40	19-136
Trail Making Test B (sec)	201.24	82.65	62-301
COWAT	29.98	10.56	12-53
Boston Naming Test	44.51	8.84	18-58
Animal fluency	11.81	4.61	5-24
ROCF copy	14.89	2.82	9-19
JOLO	10.00	2.78	5-15
HVLT-R total learning	14.79	3.81	6-20
BVMT-R total learning	7.60	2.99	2-14
HVLT-R delayed recall	2.02	2.38	0-7
BVMT-R delayed recall	2.05	1.57	0-5

Note: MMSE = Mini Mental State Examination; WAIS-III = Wechsler Adult Intelligence Scale, 3rd edition; COWAT = Controlled Oral Word Association Test; ROCF = Rey-Osterrieth Complex Figure; HVLT-R = Hopkins Verbal Learning Test–Revised; BVMT-R = Brief Visuospatial Memory Test–Revised. N = 43.

As expected, burden was positively correlated with caregiver depressive symptoms (r = .37, p < .05). Increased caregiver burden was also associated with caregiver report of increased patient frontal systems behavioral problems, including apathy (r = .46, p < .01), disinhibition (r = .44, p < .01), and executive dysfunction (r = .42, p < .01). However, no significant relationships were found between caregiver burden and patients’ neuropsychological or functional status or between caregiver burden and patient report of increased depressive symptoms.

Caregiver depressive symptoms were inversely correlated with patients’ instrumental ADLs (r = –.35, p < .05), with caregivers reporting higher levels of depressive symptoms as patients’ functional abilities declined. Increases in patients’ disinhibited behaviors were also associated with increased caregiver depressive symptoms (r = .32, p < .05). Caregiver depressive symptoms were not associated with patients’ cognition, apathetic or dysexecutive behavioral problems, or depressive symptoms.

Because caregiver burden was significantly correlated with caregiver depression and the three FrSBe subscales, the stepwise regression analysis performed for burden used these four variables as candidate predictors. At an entry level of p < .05, only FrSBe disinhibition (β = .51, p = .001) entered the regression equation; model fit: R² = .26, F(1, 40) = 13.72, p = .001.

Given that caregiver depression was significantly correlated with patients’ instrumental ADLs, patients’ disinhibited behaviors, and caregiver burden, these variables were entered into the stepwise multiple linear regression. Results show that instrumental ADLs (β = –.36, p < .05) and FrSBe disinhibition (β = –.30, p < .05) entered the regression equation; model fit: R² = .26, F(2, 37) = 6.44, p < .01.

Discussion

Findings confirm the presence of burden in caregivers of patients with MCI, with almost 30% of caregivers in this sample reporting clinically significant burden. This is very consistent with previous findings in different samples of MCI patients (Bruce et al., 2008). Patients’ level of disinhibition emerged as the only unique predictor of caregiver burden, and caregiver depressive symptoms were uniquely predicted by patients’ disinhibited behaviors and instrumental ADL impairments. Interestingly, degree of cognitive impairment was not correlated with caregiver burden or depressive symptoms. Furthermore, in line with previous research in MCI populations, caregiver burden was not associated with either patient or caregiver demographic characteristics.

When considering the specific types of frontal system behaviors which contribute to caregiver burden in the MCI population, findings suggest disinhibition was uniquely predictive of burden, whereas apathy and dysexecutive behaviors were not. Although the contributions of different types of behavioral disturbances to caregiver burden in MCI populations have not been examined, similar relationships have been found in dementia populations. Rymer et al. (2002) found disinhibited behaviors were more strongly associated with caregiver burden than apathy or dysexecutive symptoms in a sample of AD patients and their caregivers. Similarly, Davis and Tremont (2007) found a relationship between caregiver burden and both disinhibited and dysexecutive behaviors after controlling for dementia severity and caregiver depression. Taken together, these findings suggest disinhibited behaviors may be more difficult for caregivers to manage and may form a key point for intervention.

In addition, although caregiver burden and depression were correlated, findings suggest these are not interchangeable constructs. Although almost 30% of caregivers reported clinically significant burden, less than 5% of caregivers reported clinically significant depression and only one of these individuals reported significant caregiving burden. Furthermore, neither caregiver burden nor depressive symptoms emerged as unique predictors of the other in regression analyses. Caregivers not only reported increased burden and depressive symptoms as patients became more disinhibited but also reported increasing depressive symptoms as patients required more assistance with higher level ADLs such as financial and medication management, suggesting that caregivers’ mood may decline as they are required to provide more assistance with daily activities.

This study is limited by its cross-sectional nature, limiting any inferences about causality that could be answered through longitudinal designs. Research from dementia populations suggests that patients’ awareness of their cognitive and functional impairments may serve as important predictors of caregiver burden (Rymer et al., 2002; Seltzer, Vasterling, Yoder, & Thompson, 1997), and future studies may benefit from inclusion of awareness measures. In addition, patient depression was based on self-report. As some evidence exists to suggest some MCI patients may not be reliable self-reporters (Ready, Ott, & Grace, 2006), use of informant-rated measures of patients’ mood in future studies may be beneficial. Studies that include more caregivers with clinical depression, as well as comparisons to caregivers for other substantial illnesses (e.g., cancer), may also be informative.

Overall, findings from this study demonstrate the contributions of patients’ functional status and disinhibited behaviors to caregiver burden and depression. Results suggest interventions to alleviate caregiver burden and depression are important in the predementia stages, and these caregivers would benefit by addressing both practical methods to provide assistance with ADLs as well as behavioral methods to address inappropriate behaviors in patients.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Author Biographies

Beth Springate, PhD (clinical psychology/neuropsychology, University of Connecticut), is a postdoctoral fellow in neuropsychology at Rhode Island Hospital and the Alpert Medical School of Brown University. Her research interests include awareness of cognitive decline in dementia, dementia caregiving, and the cognitive effects of cerebrovascular disease.

Geoffrey Tremont, PhD (clinical psychology/neuropsychology, Nova Southeastern University), is an associate professor of psychiatry and human behavior at the Alpert Medical School of Brown University and director of neuropsychology at Rhode Island Hospital. His research interests include assessment methods and interventions for individuals with dementia and their caregivers.

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