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Early Cognitively Based Functional Limitations Predict Loss of Independence in Instrumental Activities of Daily Living in Older Adults

Published online by Cambridge University Press:  22 September 2015

Karen M. Lau ,
Mili Parikh ,
Danielle J. Harvey ,
Chun-Jung Huang  and
Sarah Tomaszewski Farias
Karen M. Lau
Affiliation:
San Francisco Veterans Affairs Medical Center, San Francisco, California Department of Neurology, School of Medicine, University of California, Davis, Sacramento, California
Mili Parikh
Affiliation:
Veterans Affairs Northern California Health Care System, Mather, California
Danielle J. Harvey
Affiliation:
Division of Biostatistics, Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, California
Chun-Jung Huang
Affiliation:
Division of Biostatistics, Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, California
Sarah Tomaszewski Farias*
Affiliation:
Department of Neurology, School of Medicine, University of California, Davis, Sacramento, California
*
Correspondence and reprint requests to: Sarah Tomaszewski Farias, Department of Neurology, School of Medicine, University of California, Davis, 4860 Y Street, Suite 3700, Sacramento, CA 95817. E-mail: sarah.farias@ucdmc.ucdavis.edu
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Abstract

Older adults with early forms of neurodegenerative disease are at risk for functional disability, which is often defined by the loss of independence in instrumental activities of daily living (IADLs). The current study investigated the influence of mild changes in everyday functional abilities (referred to as functional limitations) on risk for development of incident functional disability. A total of 407 participants, who were considered cognitively normal or diagnosed with mild cognitive impairment (MCI) at baseline, were followed longitudinally over an average 4.1 years (range=0.8–9.2 years). Informant-based ratings from the Everyday Cognition (ECog; Farias et al., 2008) and the Instrumental Activities of Daily Living (Lawton & Brody, 1969) scales assessed the degree of functional limitations and incident IADL disability, respectively. Cox proportional hazards models revealed that more severe functional limitations (as measured by the Total ECog score) at baseline were associated with approximately a four-fold increased risk of developing IADL disability a few years later. Among the ECog domains, functional limitations in Everyday Planning, Everyday Memory, and Everyday Visuospatial domains were associated with the greatest risk of incident functional disability. These results remained robust even after controlling for participants’ neuropsychological functioning on tests of executive functions and episodic memory. Current findings indicate that early functional limitations have prognostic value in identifying older adults at risk for developing functional disability. Findings highlight the importance of developing interventions to support everyday abilities related to memory, executive function, and visuospatial skills in an effort to delay loss of independence in IADLs. (JINS, 2015, 21, 688–698)

Keywords

Alzheimer’s diseaseDementiaEveryday functionInstrumental activities of daily livingCognitionDisability
Type
Research Articles
Information
Journal of the International Neuropsychological Society , Volume 21 , Issue 9 , October 2015 , pp. 688 - 698
Copyright
Copyright © The International Neuropsychological Society 2015 

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References

Albert, M.S., DeKosky, S.T., Dickson, D., Dubois, B., Feldman, H.H., Fox, N.C., & Phelps, C.H. (2011). The diagnosis of mild cognitive impairment due to Alzheimer’s disease: Recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease. Alzheimers & Dementia, 7(3), 270–279. doi:10.1016/j.jalz.2011.03.008 Google Scholar
Alzheimer’s Association Expert Advisory Workgroup on NAPA (2012). Workgroup on NAPA’s scientific agenda for a national initiative on Alzheimer’s disease. Alzheimers & Dementia, 8(4), 357–371. doi:10.1016/j.jalz.2012.04.003 Google Scholar
American Psychiatric Association (1987). Diagnostic and statistical manual of mental disorders: DSM-III-R (3rd ed.). Washington, DC: American Psychiatric Association.Google Scholar
Andersen, C.K., Wittrup-Jensen, K.U., Lolk, A., Andersen, K., & Kragh-Sorensen, P. (2004). Ability to perform activities of daily living is the main factor affecting quality of life in patients with dementia. Health and Quality of Life Outcomes, 2, 52. doi:10.1186/1477-7525-2-52 CrossRefGoogle ScholarPubMed
Aretouli, E., Okonkwo, O.C., Samek, J., & Brandt, J. (2011). The fate of the 0.5s:predictors of 2-year outcome in mild cognitive impairment. Journal of the International Neuropsychological Society, 17(2), 277–288. doi:10.1017/S1355617710001621 Google Scholar
Barberger-Gateau, P., Alioum, A., Peres, K., Regnault, A., Fabrigoule, C., Nikulin, M., &Dartigues, J.F. (2004). The contribution of dementia to the disablement process and modifying factors. Dementia and Geriatric Cognitive Disorders, 18(3-4), 330–337. doi:10.1159/000080127 Google Scholar
Barberger-Gateau, P., Fabrigoule, C., Amieva, H., Helmer, C., & Dartigues, J.F. (2002). The disablement process: A conceptual framework for dementia-associated disability. Dementia and Geriatric Cognitive Disorders, 13(2), 60–66. doi:48635 Google Scholar
Bertrand, R.M., & Willis, S.L. (1999). Everyday problem solving in Alzheimer’s patients: A comparison of subjective and objective assessments. Aging and Mental Health, 3(4), 281–293.Google Scholar
Biegel, D.E., Bass, D.M., Schulz, R., & Morycz, R. (1993). Predictors of in-home and out-of-home service use by family caregivers of Alzheimer’s disease patients. Journal of Aging and Health, 5(4), 419–438.Google Scholar
Boyle, P.A., Malloy, P.F., Salloway, S., Cahn-Weiner, D.A., Cohen, R., & Cummings, J.L. (2003). Executive dysfunction and apathy predict functional impairment in Alzheimer disease. The American Journal of Geriatric Psychiatry, 11(2), 214–221.Google Scholar
Brown, P.J., Devanand, D.P., Liu, X., & Caccappolo, E., Alzheimer’s Disease Neuroimaging Initiative. (2011). Functional impairment in elderly patients with mild cognitive impairment and mild Alzheimer disease. Archives of General Psychiatry, 68(6), 617–626. doi:10.1001/archgenpsychiatry.2011.57 Google Scholar
Buckner, R.L. (2004). Memory and executive function in aging and AD: Multiple factors that cause decline and reserve factors that compensate. Neuron, 44(1), 195–208. doi:10.1016/j.neuron.2004.09.006 CrossRefGoogle Scholar
Burton, C.L., Strauss, E., Bunce, D., Hunter, M.A., & Hultsch, D.F. (2009). Functional abilities in older adults with mild cognitive impairment. Gerontology, 55(5), 570–581. doi:10.1159/000228918 Google Scholar
Cahn-Weiner, D.A., Farias, S.T., Julian, L., Harvey, D.J., Kramer, J.H., Reed, B.R., & Chui, H. (2007). Cognitive and neuroimaging predictors of instrumental activities of daily living. Journal of the International Neuropsychological Society, 13(5), 747–757. doi:10.1017/S1355617707070853 Google Scholar
Cahn-Weiner, D.A., Malloy, P.F., Boyle, P.A., Marran, M., & Salloway, S. (2000). Prediction of functional status from neuropsychological tests in community-dwelling elderly individuals. The Clinical Neuropsychologist, 14(2), 187–195. doi:10.1076/1385-4046(200005)14:2;1-Z;FT187 Google Scholar
Cahn-Weiner, D.A., Ready, R.E., & Malloy, P.F. (2003). Neuropsychological predictors of everyday memory and everyday functioning in patients with mild Alzheimer’s disease. Journal of Geriatric Psychiatry and Neurology, 16(2), 84–89.Google Scholar
Chaytor, N., & Schmitter-Edgecombe, M. (2003). The ecological validity of neuropsychological tests: A review of the literature on everyday cognitive skills. Neuropsychology Review, 13(4), 181–197.Google Scholar
Conde-Sala, J.L., Garre-Olmo, J., Turro-Garriga, O., Lopez-Pousa, S., & Vilalta-Franch, J. (2009). Factors related to perceived quality of life in patients with Alzheimer’s disease: The patient’s perception compared with that of caregivers. International Journal of Geriatric Psychiatry, 24(6), 585–594. doi:10.1002/gps.2161 Google Scholar
Farias, S.T., Chou, E., Harvey, D.J., Mungas, D., Reed, B., DeCarli, C., & Beckett, L. (2013). Longitudinal trajectories of everyday function by diagnostic status. Psychology and Aging, 28(4), 1070–1075. doi:10.1037/a0034069 Google Scholar
Farias, S.T., Mungas, D., & Jagust, W. (2005). Degree of discrepancy between self and other-reported everyday functioning by cognitive status: Dementia, mild cognitive impairment, and healthy elders. International Journal of Geriatric Psychiatry, 20(9), 827–834. doi:10.1002/gps.1367 Google Scholar
Farias, S.T., Mungas, D., Reed, B., Haan, M.N., & Jagust, W.J. (2004). Everyday functioning in relation to cognitive functioning and neuroimaging in community-dwelling Hispanic and non-Hispanic older adults. Journal of the International Neuropsychological Society, 10(3), 342–354. doi:10.1017/S1355617704103020 CrossRefGoogle ScholarPubMed
Farias, S.T., Mungas, D., Reed, B.R., Cahn-Weiner, D., Jagust, W., Baynes, K., & Decarli, C. (2008). The measurement of everyday cognition (ECog): Scale development and psychometric properties. Neuropsychology, 22(4), 531–544. doi:10.1037/0894-4105.22.4.531 CrossRefGoogle ScholarPubMed
Farias, S.T., Mungas, D., Reed, B.R., Harvey, D., Cahn-Weiner, D., & Decarli, C. (2006). MCI is associated with deficits in everyday functioning. Alzheimer Disease and Associated Disorders, 20(4), 217–223. doi:10.1097/01.wad.0000213849.51495.d9 Google Scholar
Farias, S.T., Mungas, D., Reed, B.R., Harvey, D., & DeCarli, C. (2009). Progression of mild cognitive impairment to dementia in clinic- vs community-based cohorts. Archives of Neurology, 66(9), 1151–1157. doi:10.1001/archneurol.2009.106 Google Scholar
Farias, S.T., Park, L.Q., Harvey, D.J., Simon, C., Reed, B.R., Carmichael, O., & Mungas, D. (2013). Everyday cognition in older adults: Associations with neuropsychological performance and structural brain imaging. Journal of the International Neuropsychological Society, 19(4), 430–441. doi:10.1017/S1355617712001609 Google Scholar
Gallagher, D., Ni Mhaolain, A., Crosby, L., Ryan, D., Lacey, L., Coen, R.F., & Lawlor, B.A. (2011). Dependence and caregiver burden in Alzheimer’s disease and mild cognitive impairment. American Journal of Alzheimer’s Disease and Other Dementias, 26(2), 110–114. doi:10.1177/1533317510394649 Google Scholar
Gaugler, J.E., Hovater, M., Roth, D.L., Johnston, J.A., Kane, R.L., & Sarsour, K. (2013). Analysis of cognitive, functional, health service use, and cost trajectories prior to and following memory loss. The Journals of Gerontology. Series B: Psychological Sciences and Social Sciences, 68(4), 562–567. doi:10.1093/geronb/gbs078 CrossRefGoogle ScholarPubMed
Gaugler, J.E., Kane, R.L., Kane, R.A., Clay, T., & Newcomer, R. (2003). Caregiving and institutionalization of cognitively impaired older people: Utilizing dynamic predictors of change. Gerontologist, 43(2), 219–229.Google Scholar
Glosser, G., Gallo, J., Duda, N., de Vries, J.J., Clark, C.M., & Grossman, M. (2002). Visual perceptual functions predict instrumental activities of daily living in patients with dementia. Neuropsychiatry, Neuropsychology, and Behavioral Neurology, 15(3), 198–206.Google Scholar
Gomar, J.J., Bobes-Bascaran, M.T., Conejero-Goldberg, C., Davies, P., & Goldberg, T.E., Alzheimer’s Disease Neuroimaging Initiative (2011). Utility of combinations of biomarkers, cognitive markers, and risk factors to predict conversion from mild cognitive impairment to Alzheimer disease in patients in the Alzheimer’s disease neuroimaging initiative. Archives of General Psychiatry, 68(9), 961–969. doi:10.1001/archgenpsychiatry.2011.96 Google Scholar
Gonzalez, H.M., Mungas, D., & Haan, M.N. (2002). A verbal learning and memory test for English- and Spanish-speaking older Mexican-American adults. The Clinical Neuropsychologist, 16(4), 439–451. doi:10.1076/clin.16.4.439.13908 Google Scholar
Greenaway, M.C., Duncan, N.L., & Smith, G.E. (2013). The memory support system for mild cognitive impairment: Randomized trial of a cognitive rehabilitation intervention. International Journal of Geriatric Psychiatry, 28(4), 402–409. doi:10.1002/gps.3838 Google Scholar
Greenaway, M.C., Hanna, S.M., Lepore, S.W., & Smith, G.E. (2008). A behavioral rehabilitation intervention for amnestic mild cognitive impairment. American Journal of Alzheimer’s Disease and Other Dementias, 23(5), 451–461. doi:10.1177/1533317508320352 Google Scholar
Hsiung, G.Y., Alipour, S., Jacova, C., Grand, J., Gauthier, S., Black, S.E., &Feldman, H.H. (2008). Transition from cognitively impaired not demented to Alzheimer’s disease: An analysis of changes in functional abilities in a dementia clinic cohort. Dementia and Geriatric Cognitive Disorders, 25(6), 483–490. doi:10.1159/000126499 Google Scholar
Jack, C.R. Jr., Knopman, D.S., Jagust, W.J., Shaw, L.M., Aisen, P.S., Weiner, M.W., & Trojanowski, J.Q. (2010). Hypothetical model of dynamic biomarkers of the Alzheimer’s pathological cascade. The Lancet. Neurology, 9(1), 119–128. doi:10.1016/S1474-4422(09)70299-6 Google Scholar
Jacoby, M., Averbuch, S., Sacher, Y., Katz, N., Weiss, P.L., & Kizony, R. (2013). Effectiveness of executive functions training within a virtual supermarket for adults with traumatic brain injury: A pilot study. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 21(2), 182–190. doi:10.1109/TNSRE.2012.2235184 Google Scholar
Jefferson, A.L., Barakat, L.P., Giovannetti, T., Paul, R.H., & Glosser, G. (2006). Object perception impairments predict instrumental activities of daily living dependence in Alzheimer’s disease. Journal of Clinical and Experimental Neuropsychology, 28(6), 884–897. doi:10.1080/13803390591001034 Google Scholar
Jette, A.M. (2006). Toward a common language for function, disability, and health. Physical Therapy, 86(5), 726–734.Google Scholar
Jette, D.U., Manago, D., Medved, E., Nickerson, A., Warzycha, T., & Bourgeois, M.C. (1997). The disablement process in patients with pulmonary disease. Physical Therapy, 77(4), 385–394.Google Scholar
Jorm, A.F., Christensen, H., Henderson, A.S., Korten, A.E., Mackinnon, A.J., & Scott, R. (1994). Complaints of cognitive decline in the elderly: A comparison of reports by subjects and informants in a community survey. Psychological Medicine, 24(2), 365–374.Google Scholar
Lawton, M.P., & Brody, E.M. (1969). Assessment of older people: Self-maintaining and instrumental activities of daily living. Gerontologist, 9(3), 179–186.Google Scholar
Levine, B., Schweizer, T.A., O’Connor, C., Turner, G., Gillingham, S., Stuss, D.T., & Robertson, I.H. (2011). Rehabilitation of executive functioning in patients with frontal lobe brain damage with goal management training. Frontiers in Human Neuroscience, 5, 9. doi:10.3389/fnhum.2011.00009 Google Scholar
Levine, B., Stuss, D.T., Winocur, G., Binns, M.A., Fahy, L., Mandic, M., & Robertson, I.H. (2007). Cognitive rehabilitation in the elderly: Effects on strategic behavior in relation to goal management. Journal of the International Neuropsychological Society, 13(1), 143–152. doi:10.1017/S1355617707070178 Google Scholar
Marshall, G.A., Zoller, A.S., Kelly, K.E., Amariglio, R.E., Locascio, J.J., … Johnson, K.A., For The Alzheimer’s Disease Neuroimaging Initiative (2014). Everyday cognition scale items that best discriminate between and predict progression from clinically normal to mild cognitive impairment. Current Alzheimer Research, 11(9), 853–861.Google Scholar
McAlister, C., & Schmitter-Edgecombe, M. (2013). Naturalistic assessment of executive function and everyday multitasking in healthy older adults. Neuropsychology, Development, and Cognition. Section B, Aging, Neuropsychology and Cognition, 20(6), 735–756. doi:10.1080/13825585.2013.781990 Google Scholar
McDonough, C.M., & Jette, A.M. (2010). The contribution of osteoarthritis to functional limitations and disability. Clinics in Geriatric Medicine, 26(3), 387–399. doi:10.1016/j.cger.2010.04.001 Google Scholar
Morales, J.M., Bermejo, F., Romero, M., & Del-Ser, T. (1997). Screening of dementia in community-dwelling elderly through informant report. International Journal of Geriatric Psychiatry, 12(8), 808–816.Google Scholar
Morris, J.C., Weintraub, S., Chui, H.C., Cummings, J., Decarli, C., Ferris, S., & Kukull, W.A. (2006). The Uniform Data Set (UDS): Clinical and cognitive variables and descriptive data from Alzheimer Disease Centers. Alzheimer Disease and Associated Disorders, 20(4), 210–216. doi:10.1097/01.wad.0000213865.09806.92 CrossRefGoogle ScholarPubMed
Mungas, D., Reed, B.R., Crane, P.K., Haan, M.N., & Gonzalez, H. (2004). Spanish and English Neuropsychological Assessment Scales (SENAS): Further development and psychometric characteristics. Psychological Assessment, 16(4), 347–359. doi:10.1037/1040-3590.16.4.347 Google Scholar
Mungas, D., Reed, B.R., Marshall, S.C., & Gonzalez, H.M. (2000). Development of psychometrically matched English and Spanish language neuropsychological tests for older persons. Neuropsychology, 14(2), 209–223.Google Scholar
Mungas, D., Reed, B.R., Tomaszewski Farias, S., & DeCarli, C. (2005). Criterion-referenced validity of a neuropsychological test battery: Equivalent performance in elderly Hispanics and non-Hispanic Whites. Journal of the International Neuropsychological Society, 11(5), 620–630. doi:10.1017/S1355617705050745 Google Scholar
Nelson, P.T., Braak, H., & Markesbery, W.R. (2009). Neuropathology and cognitive impairment in Alzheimer disease: A complex but coherent relationship. Journal of Neuropathology and Expimental Neurology, 68(1), 1–14. doi:10.1097/NEN.0b013e3181919a48 Google Scholar
Panza, F., Solfrizzi, V., Barulli, M.R., Santamato, A., Seripa, D., Pilotto, A., &Logroscino, G. (2015). Cognitive frailty - Epidemiological and neurobiological evidence of an age-related clinical condition: A systematic review. Rejuvenation Research, doi:10.1089/rej.2014.1637 Google Scholar
Peres, K., Helmer, C., Amieva, H., Matharan, F., Carcaillon, L., Jacqmin-Gadda, H., & Dartigues, J.F. (2011). Gender differences in the prodromal signs of dementia: Memory complaint and IADL-restriction. a prospective population-based cohort. Journal of Alzheimer’s Disease, 27(1), 39–47. doi:10.3233/JAD-2011-110428 Google Scholar
Peres, K., Helmer, C., Letenneur, L., Jacqmin-Gadda, H., … Barberger-Gateau, P. (2005). Ten-year change in disability prevalence and related factors in two generations of French elderly community dwellers: Data from the PAQUID study. Aging Clinical and Experimental Research, 17(3), 229–235.Google Scholar
Peres, K., Verret, C., Alioum, A., & Barberger-Gateau, P. (2005). The disablement process: Factors associated with progression of disability and recovery in French elderly people. Disability and Rehabilitation, 27(5), 263–276.Google Scholar
Perneczky, R., Pohl, C., Sorg, C., Hartmann, J., Komossa, K., Alexopoulos, P., & Kurz, A. (2006). Complex activities of daily living in mild cognitive impairment: Conceptual and diagnostic issues. Age and Ageing, 35(3), 240–245. doi:10.1093/ageing/afj054 Google Scholar
Possin, K.L. (2010). Visual spatial cognition in neurodegenerative disease. Neurocase, 16(6), 466–487. doi:10.1080/13554791003730600 Google Scholar
Purser, J.L., Fillenbaum, G.G., Pieper, C.F., & Wallace, R.B. (2005). Mild cognitive impairment and 10-year trajectories of disability in the Iowa Established Populations for Epidemiologic Studies of the Elderly cohort. Journal of the American Geriatrics Society, 53(11), 1966–1972. doi:10.1111/j.1532-5415.2005.53566.x Google Scholar
Razani, J., Kakos, B., Orieta-Barbalace, C., Wong, J.T., Casas, R., Lu, P., & Josephson, K. (2007). Predicting caregiver burden from daily functional abilities of patients with mild dementia. Journal of the American Geriatrics Society, 55(9), 1415–1420. doi:10.1111/j.1532-5415.2007.01307.x Google Scholar
Rebok, G.W., Ball, K., Guey, L.T., Jones, R.N., Kim, H.Y., King, J.W., & Group, A.S. (2014). Ten-year effects of the advanced cognitive training for independent and vital elderly cognitive training trial on cognition and everyday functioning in older adults. Journal of the American Geriatrics Society, 62(1), 16–24. doi:10.1111/jgs.12607 Google Scholar
Robertson, I.H. (1996). Goal management training: A clinical manual. Cambridge: PsyConsult.Google Scholar
Robinson, K.M., Buckwalter, K.C., & Reed, D. (2005). Predictors of use of services among dementia caregivers. Western Journal of Nursing Research, 27(2), 126–140; discussion 141–147. doi:10.1177/0193945904272453 Google Scholar
Rueda, A.D., Lau, K.L., Saito, N., Harvey, D., Risacher, S.L., & Aisen, P.S., Alzheimer’s Disease Neuroimaging Initiative. (inpress). Self-rated and informant-rated everyday function in comparison to objective markers of Alzheimer’s disease. Alzheimers & Dementia, doi:http://dx.doi.org/10.1016/j.jalz.2014.09.002 Google Scholar
Ruscio, J. (2008). A probability-based measure of effect size: Robustness to base rates and other factors. Psychological Methods, 13(1), 19–30. doi:10.1037/1082-989X.13.1.19 Google Scholar
Safren, S.A., Sprich, S., Mimiaga, M.J., Surman, C., Knouse, L., Groves, M., & Otto, M.W. (2010). Cognitive behavioral therapy vs relaxation with educational support for medication-treated adults with ADHD and persistent symptoms: A randomized controlled trial. Journal of the American Medical Association, 304(8), 875–880. doi:10.1001/jama.2010.1192 Google Scholar
Schinka, J.A. (2010). Use of informants to identify mild cognitive impairment in older adults. Current Psychiatry Reports, 12(1), 4–12. doi:10.1007/s11920-009-0079-9 Google Scholar
Schmitter-Edgecombe, M., Woo, E., & Greeley, D.R. (2009). Characterizing multiple memory deficits and their relation to everyday functioning in individuals with mild cognitive impairment. Neuropsychology, 23(2), 168–177. doi:10.1037/a0014186 Google Scholar
Solanto, M.V., Marks, D.J., Mitchell, K.J., Wasserstein, J., & Kofman, M.D. (2008). Development of a new psychosocial treatment for adult ADHD. Journal of Attention Disorders, 11(6), 728–736. doi:10.1177/1087054707305100 Google Scholar
Spooner, D.M., & Pachana, N.A. (2006). Ecological validity in neuropsychological assessment: A case for greater consideration in research with neurologically intact populations. Archives of Clinical Neuropsychology, 21(4), 327–337. doi:10.1016/j.acn.2006.04.004 Google Scholar
Tabert, M.H., Albert, S.M., Borukhova-Milov, L., Camacho, Y., Pelton, G., Liu, X., & Devanand, D.P. (2002). Functional deficits in patients with mild cognitive impairment: Prediction of AD. Neurology, 58(5), 758–764.Google Scholar
Tucker-Drob, E.M. (2011). Neurocognitive functions and everyday functions change together in old age. Neuropsychology, 25(3), 368–377. doi:10.1037/a0022348 Google Scholar
Verbrugge, L.M., & Jette, A.M. (1994). The disablement process. Social Science & Medicine (1982), 38(1), 1–14.Google Scholar
Wattmo, C., Londos, E., & Minthon, L. (2014). Solitary living in Alzheimer’s disease over 3 years: Association between cognitive and functional impairment and community-based services. Clinical Interventions in Aging, 9, 1951–1962. doi:10.2147/CIA.S71709 Google Scholar
Weintraub, S., Salmon, D., Mercaldo, N., Ferris, S., Graff-Radford, N.R., Chui, H., & Morris, J.C. (2009). The Alzheimer’s Disease Centers’ Uniform Data Set (UDS): The neuropsychologic test battery. Alzheimer Disease and Associated Disorders, 23(2), 91–101. doi:10.1097/WAD.0b013e318191c7dd Google Scholar
Willis, S.L., Tennstedt, S.L., Marsiske, M., Ball, K., Elias, J., & Koepke, K.M., Active Study Group (2006). Long-term effects of cognitive training on everyday functional outcomes in older adults. Journal of the American Medical Association, 296(23), 2805–2814. doi:10.1001/jama.296.23.2805 Google Scholar
Zanetti, O., Geroldi, C., Frisoni, G.B., Bianchetti, A., & Trabucchi, M. (1999). Contrasting results between caregiver’s report and direct assessment of activities of daily living in patients affected by mild and very mild dementia: The contribution of the caregiver’s personal characteristics. Journal of the American Geriatric Society, 47(2), 196–202.CrossRefGoogle ScholarPubMed
Zhu, C.W., Leibman, C., McLaughlin, T., Zbrozek, A.S., Scarmeas, N., Albert, M., & Stern, Y. (2008). Patient dependence and longitudinal changes in costs of care in Alzheimer’s disease. Dementia and Geriatric Cognitive Disorders, 26(5), 416–423. doi:10.1159/000164797 Google Scholar