Norton, M.C. , Piercy, K.W. , Rabins, P.V. , Green, R.C. , Breitner, J.C.S. , Østbye, T., Corcoran, C., Welsh-Bohmer, K.A. , Lyketsos, C.G. , & Tschanz, J.T. (2009). Caregiver – recipient closeness and symptom
progression in alzheimer disease. The cache county dementia progression study. Journal of Gerontology: Psychological Sciences, 64B(5), 560–568, doi:10.1093/geronb/gbp052. Advance Access publication
on June 29, 2009.
© The Author 2009. Published by Oxford University Press on behalf of The Gerontological Society of America.
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lion cases projected by the year 2050 in the United States
alone ( Alzheimer ’ s Association, 2008 ). Strong efforts have
been made to identify factors that might delay or prevent
its onset. These factors include several potentially disease-
modifying interventions intended to modify cleavage of
the amyloid precursor protein or to control the hyperphos-
phorylation of tau, infl ammation, oxidation, or excitotox-
icity ( Salloway, Mintzer, Weiner, & Cummings, 2008 ).
Less thoroughly studied are nonpharmacological factors
such as caregiving environment or practices that may delay
the progression of symptoms in AD.
Estimates from clinic-based studies suggest that the
cognitive abilities of persons with AD decline by 0.8 – 4.4
points per year on the Mini-Mental State Exam (MMSE),
with the typical decline of about 3 points per year ( Behl,
Stefurak, & Black, 2005 ). Two population-based studies
have reported decline rates of 2.3 – 2.9 MMSE points per
year ( Aguero-Torres, Fratiglioni, Guo, Viitanen, & Winblad,
1998 ; Slooter et al., 1999 ), and we recently published a
LZHEIMER ’ S dementia (AD) remains a major pub-
lic health problem, with a prevalence of 11 – 16 mil-
mean decline of 1.9 (95% CI = 1.7 – 2.1) MMSE points
per year in persons with newly diagnosed AD from the
population of Cache County, Utah ( Mielke et al., 2007 ).
More rapid decline has been associated with higher educa-
tion in some ( Stern, Albert, Tang, & Tsai, 1999 ; Teri,
McCurry, Edland, Kukull, & Larson, 1995 ) but not all
( Bowler, Munoz, Merskey, & Hachinski, 1998 ; Regan
et al., 2006 ; Small, Viitanen, Winblad, & Backman, 1997 )
samples. Similarly, more rapid decline has been reported
in the presence of comorbid medical conditions, especially
vascular risk factors ( Mielke et al., 2007 ) and with younger
onset age in some ( Teri et al., 1995 ; Lucca, Comelli,
Tettamanti, Tiraboschi, & Spagnoli, 1993 ) but not all
( Bowler et al., 1998 ; Small et al., 1997 ; R. G. Stern et al., 1994 )
Studies. Finally, more rapid cognitive decline has also been
associated with baseline behavioral disturbances such as
agitation and psychosis ( Scarmeas et al., 2005 ; Y. Stern
et al., 1994 ). Thus, there is evidence that education, co-
morbid medical conditions — in particular, vascular health
conditions — and behavioral disturbances are important
moderators of decline in AD.
Caregiver – Recipient Closeness and Symptom Progression
in Alzheimer Disease. The Cache County Dementia
Maria C. Norton , 1 , 2 , 3 Kathleen W. Piercy , 1 , 3 Peter V. Rabins , 4 Robert C. Green , 5 , 6 , 7 John C. S. Breitner , 8 , 9
Truls Østbye , 10 Christopher Corcoran , 3 , 11 Kathleen A. Welsh-Bohmer , 12 , 13
Constantine G. Lyketsos , 4 , * and JoAnn T. Tschanz 2 , 3 , *
1 Department of Family, Consumer and Human Development , 2 Department of Psychology , and 3 Center for Epidemiologic Studies,
Utah State University, Logan .
4 Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland .
5 Department of Neurology , and 6 Department of Medicine (Genetics), Boston University School of Medicine, Massachusetts .
7 Department of Epidemiology, Boston University School of Public Health, Massachusetts .
8 VA Puget Sound Health Care System, Seattle, Washington .
9 Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle .
10 Department of Community and Family Medicine, Duke University Medical Center, Durham, North Carolina .
11 Department of Mathematics and Statistics, Utah State University, Logan .
12 Department of Psychiatry and Behavioral Sciences , and 13 Bryan Alzheimer ’ s Disease Research Center, Duke University Medical
Center, Durham, North Carolina .
Applying Rusbult ’ s investment model of dyadic relationships, we examined the effect of caregiver – care recipient
relationship closeness (RC) on cognitive and functional decline in Alzheimer ’ s disease. After diagnosis, 167 par-
ticipants completed up to six visits, observed over an average of 20 months. Participants were 64% women, had a
mean age of 86 years, and mean dementia duration of 4 years. Caregiver-rated closeness was measured using a
six-item scale. In mixed models adjusted for dementia severity, dyads with higher levels of closeness ( p < .05) and
with spouse caregivers ( p = .01) had slower cognitive decline. Effect of higher RC on functional decline was greater
with spouse caregivers ( p = .007). These fi ndings of attenuated Alzheimer ’ s dementia (AD) decline with closer re-
lationships, particularly with spouse caregivers, are consistent with investment theory. Future interventions de-
signed to enhance the caregiving dyadic relationship may help slow decline in AD.
Key Words: Alzheimer ’ s disease — Caregiving — Interpersonal relations .
by guest on October 29, 2015
CAREGIVER CLOSENESS AND AD SYMPTOM PROGRESSION
Although several studies have examined the effects of
the clinical features of dementia on caregiver well-being
( Gaugler, Davey, Pearlin, & Zarit, 2000 ; Ory, Hoffman, Yee,
Tennstedt, & Schulz, 1999 ), little is known about the extent
to which decline in dementia is modifi ed by the care envi-
ronment. Kitwood (1993) has argued that dementia caregiv-
ing is a “ cooperative and reciprocal engagement ” (pp.
64 – 65) that requires a caregiver to be emotionally available
to the care recipient (CR), have high levels of empathy and
imagination, and engage in fl exible thinking. This approach
posits that acceptance of the validity of CRs ’ experiences
and accurate identifi cation of their needs are crucial to de-
velopment of a positive care environment. This hypothesis
is supported by studies demonstrating that “ nonadapting ”
(nonacceptance) strategies appear to predict worse out-
comes than “ supporting ” strategies (adapting to the CR ’ s
level; de Vugt et al., 2004 ), and a longitudinal study of spou-
sal dementia care demonstrating that positive spousal inter-
actions, high caregiver commitment, good caregiver health,
and shorter caregiving duration were all associated with de-
layed nursing home placement in dementia ( Wright, 1994 ).
Support for the hypothesis that the care environment infl u-
ences the progression of dementia symptoms is provided
by clinical trial fi ndings that caregiver interventions in-
tended to stimulate cognitive abilities in dementia patients
may also attenuate their cognitive decline ( Quayhagen &
Quayhagen, 2001 ), improve the quality of life for both care-
givers and their CRs ( Quayhagen & Quayhagen, 1996 ), and
delay nursing home placement ( Mittelman, Haley, Clay, &
Roth, 2006 ).
Several studies have examined the association of care-
giver and CR relationships and selected outcomes. Closer
perceived relationships are associated with better adjust-
ment to nursing home placement in persons with dementia
( Whitlatch, Schur, Noelker, Ejaz, & Looman, 2001 ) and
improved psychological well-being and problem-solving
abilities ( Burgener & Twigg, 2002 ). Conversely, avoid-
ance by caregivers or insecure attachment styles in their
CRs have been associated with more behavioral problems
in the latter ( Perren, Schmid, Herrmann, & Wettstein,
2007 ). Graham and Bassett ’ s (2006) longitudinal ethno-
graphic study of persons with Alzheimer ’ s disease and
their family caregivers presents strong evidence that car-
ing relationships are “ dynamic co-constructions built
upon everyday events, interactions, environments, and
disease progression ” (p. 335). In their study, cooperative
care relationships were built on foundations of mutual
respect and sensitivity to persons with dementia, whereas
lack of trust and compassion leads to unrealistic expecta-
tions and negative reciprocity. In the current study, we
used interdependence theory ( Kelley & Thibaut, 1978 )
and the investment model of commitment ( Rusbult &
Buunk, 1993 ) to guide development of hypotheses. For-
mulated to explain behavior in dyadic relationships, inter-
dependence theory holds that relationship partners become
interdependent over time through their interactions. As in-
terdependence increases, so does concern for the partner ’ s
outcomes, and a transformation of motives occurs from
motives of self-interest to prorelationship motives ( Lewis
et al., 2006 ). The investment model suggests that interde-
pendence is felt as commitment, characterized by desire
to maintain the relationship through good and bad times
( Rusbult & Buunk, 1993 ). To that end, investments are
made, including sacrifi ce for one ’ s partner. Using these
theories, and the signifi cant association between positive
spousal interactions, high caregiver commitment, and fa-
vorable outcomes in persons with dementia noted previ-
ously ( Wright, 1994 ), we would expect relationships
between AD caregivers and their CRs characterized as
close to result in more favorable cognitive and functional
Given the evidence that aspects of the care environment
are associated with more favorable outcomes in dementia,
we examined whether rate of progression of dementia is in-
fl uenced by type of relationship (spouse vs adult child) and
caregiver – CR relationship closeness (RC) in a population-
based sample of persons with AD. We hypothesized that
CRs with spouse caregivers, and those whose caregiver
rated their relationship as closer, would experience slower
rates of cognitive and functional decline.
The Cache County Dementia Progression Study (CC-DPS)
is one of few population-based studies of dementia progres-
sion in an incidence cohort, examining longitudinal cogni-
tive, functional, and behavioral outcomes and the factors
that may modify their course. Individuals were enrolled in
the CC-DPS between 2002 and 2004 after fi rst being diag-
nosed between 1998 and 2002 with new- onset dementia in
the Cache County Memory Study (CCMS), a longitudinal
population-based study of dementia that has now completed
four triennial “ waves ” of dementia ascertainment using a
multistage case detection protocol ( Breitner et al., 1999 ;
Miech et al., 2002 ). The CCMS has identifi ed 357 prevalent
and 473 new-onset (after baseline) cases of dementia.
Since the start of the CC-DPS in 2002, 241 individuals
(87% of those still living when recruited for CC-DPS) diag-
nosed in the parent study with new-onset dementia, along
with their principal caregivers, were enrolled. Among this
panel, 183 (75.9%) had been diagnosed by a clinical review
panel with possible or probable AD according to the National
Institute of Neurological and communicative Disorders and
Stroke and the Alzheimer’s Disease and Related Disorders
Association (NINCSA-ADRDA) criteria ( McKhann et al.,
1984 ). Of these, we excluded nine persons with dementia who
had caregivers other than spouses or adult children, two missing
relationship type, and fi ve whose caregiver did not complete
by guest on October 29, 2015
NORTON ET AL.
Whitlatch , C. J. , Judge , K. , Zarit , S. H. , & Femia , E. ( 2006 ). Dyadic inter-
vention for family caregivers and care receivers in early-stage de-
mentia . The Gerontologist , 46 , 688 – 694 .
Whitlatch , C. J. , Schur , D. , Noelker , L. S. , Ejaz , F. K. , & Looman , W. J.
( 2001 ). The stress process of family caregiving in institutional set-
tings . The Gerontologist , 41 , 462 – 473 .
Wright , L. K. ( 1994 ). Alzheimer ’ s disease affl icted spouses who remain at
home: Can human dialectics explain the fi ndings? Social Science &
Medicine , 38 , 1037 – 1046 .
Received October 27 , 2008
Accepted May 25 , 2009
Decision Editor: Rosemary Blieszner, PhD
by guest on October 29, 2015