Objectives: The aim of this study was to explore what effects the carer's burden and patient's neuropsychiatric symptoms have on carer's report on patient's cognitive functioning and instrumental activities of daily living (IADL). Methods: We included 1,832 patients, 742 with mild cognitive impairment and 1,090 with dementia [mean age 75.2 years (SD 9.5), 56% women]. The following scales were used: Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), Lawton and Brody IADL Scale, Neuropsychiatric Inventory Questionnaire (NPI-Q), Relatives' Stress Scale (RSS), Mini-Mental State Examination (MMSE), and Clock Drawing Test (CDT). Correlation analyses and multiple linear regression analyses were carried out to explore which factors were associated with IQCODE and IADL. Results: Spouses scored lower on the IQCODE compared with non-spouses in spite of equivalent MMSE and CDT scores. In a multiple linear regression analysis using IQCODE as a dependent variable, beta for MMSE was -0.368 (p < 0.001) adjusted for demographic factors. After adjusting also for RSS and NPI-Q, MMSE beta was -0.279 (p < 0.001), RSS beta 0.294 (p < 0.001), and NPI beta 0.237 (p < 0.001). Similar results were found using IADL as the dependent variable. Conclusion: Carer's burden and neuropsychiatric symptoms of the patient are important biasing factors when carers report on cognitive function and IADL.

Keywords:
Dementia, Mild cognitive impairment, Carer burden, Carer information, Neuropsychiatric symptoms, Informant Questionnaire on Cognitive Decline in the Elderly, Instrumental activities of daily living
1.
American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, ed 5. Washington, American Psychiatric Publishing, 2013.
2.
World Health Organization: The ICD-10 Classification of Mental and Behavioural Disorders: Diagnostic Criteria for Research. Geneva, World Health Organization, 1993.
3.
McKhann GM, Knopman DS, Chertkow H, Hyman BT, Jack CR Jr, Kawas CH, et al: The diagnosis of dementia due to Alzheimer's disease: recommendations from the National Institute on Aging-Alzheimer's Association workgroups on diagnostic guidelines for Alzheimer's disease. Alzheimers Dement 2011;7:263-269.
4.
Waldemar G, Dubois B, Emre M, Georges J, McKeith IG, Rossor M, et al: Recommendations for the diagnosis and management of Alzheimer's disease and other disorders associated with dementia: EFNS guideline. Eur J Neurol 2007;14:e1-e26.
5.
SBU: Demenssjukdomar En systematisk litteraturöversikt 2006. http://www.sbu.se/upload/Publikationer/Content0/1/Demens_sammanfattning.pdf.
6.
Rosen HJ: Anosognosia in neurodegenerative disease. Neurocase 2011;17:231-241.
7.
Li F, Jia XF, Jia J: The Informant Questionnaire on Cognitive Decline in the Elderly individuals in screening mild cognitive impairment with or without functional impairment. J Geriatr Psychiatry Neurol 2012;25:227-232.
8.
Jorm AF, Jacomb PA: The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): socio-demographic correlates, reliability, validity and some norms. Psychol Med 1989;19:1015-1022.
9.
Jorm AF: Assessment of cognitive impairment and dementia using informant reports. Clin Psychol Rev 1996;16:51-73.
10.
Winblad B, Palmer K, Kivipelto M, Jelic V, Fratiglioni L, Wahlund LO, et al: Mild cognitive impairment - beyond controversies, towards a consensus: report of the International Working Group on Mild Cognitive Impairment. J Intern Med 2004;256:240-246.
11.
Spering CC, Hobson V, Lucas JA, Menon CV, Hall JR, O'Bryant SE: Diagnostic accuracy of the MMSE in detecting probable and possible Alzheimer's disease in ethnically diverse highly educated individuals: an analysis of the NACC database. J Gerontol A Biol Sci Med Sci 2012;67:890-896.
12.
Barona A, Reynolds CR, Chastain R: A demographically based index of premorbid intelligence for the WAIS-R. J Consult Clin Psychol 1984;52:885-887.
13.
Stein J, Luppa M, Brahler E, Konig HH, Riedel-Heller SG: The assessment of changes in cognitive functioning: reliable change indices for neuropsychological instruments in the elderly - a systematic review. Dement Geriatr Cogn Disord 2010;29:275-286.
14.
Nelson HE, O'Connell A: Dementia: the estimation of premorbid intelligence levels using the New Adult Reading Test. Cortex 1978;14:234-244.
15.
Mutchnick MG, Williams JM: Anxiety and memory test performance. Appl Neuropsychol Adult 2012;19:241-248.
16.
Dahlrup B, Nordell E, Andren S, Elmstahl S: Family caregivers' assessment of symptoms in persons with dementia using the GBS-scale: differences in rating after psychosocial intervention - an 18-month follow-up study. Clin Interv Aging 2011;6:9-18.
17.
Loewenstein DA, Arguelles S, Bravo M, Freeman RQ, Arguelles T, Acevedo A, et al: Caregivers' judgments of the functional abilities of the Alzheimer's disease patient: a comparison of proxy reports and objective measures. J Gerontol B Psychol Sci Soc Sci 2001;56:P78-P84.
18.
Dassel KB, Schmitt FA: The impact of caregiver executive skills on reports of patient functioning. Gerontologist 2008;48:781-792.
19.
Conde-Sala JL, Rene-Ramirez R, Turro-Garriga O, Gascon-Bayarri J, Juncadella-Puig M, Moreno-Cordon L, et al: Factors associated with the variability in caregiver assessments of the capacities of patients with Alzheimer disease. J Geriatr Psychiatry Neurol 2013;26:86-94.
20.
Zanetti O, Geroldi C, Frisoni GB, Bianchetti A, Trabucchi M: 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. J Am Geriatr Soc 1999;47:196-202.
21.
Mangone CA, Sanguinetti RM, Baumann PD, Gonzalez RC, Pereyra S, Bozzola FG, et al: Influence of feelings of burden on the caregiver's perception of the patient's functional status. Dementia 1993;4:287-293.
22.
Pfeifer L, Drobetz R, Fankhauser S, Mortby ME, Maercker A, Forstmeier S: Caregiver rating bias in mild cognitive impairment and mild Alzheimer's disease: impact of caregiver burden and depression on dyadic rating discrepancy across domains. Int Psychogeriatr 2013;25:1345-1355.
23.
Arguelles S, Loewenstein DA, Eisdorfer C, Arguelles T: Caregivers' judgments of the functional abilities of the Alzheimer's disease patient: impact of caregivers' depression and perceived burden. J Geriatr Psychiatry Neurol 2001;14:91-98.
24.
Schulz R, Cook TB, Beach SR, Lingler JH, Martire LM, Monin JK, et al: Magnitude and causes of bias among family caregivers rating Alzheimer disease patients. Am J Geriatr Psychiatry 2013;21:14-25.
25.
Arons AM, Krabbe PF, Scholzel-Dorenbos CJ, Van der Wilt GJ, Rikkert MG: Quality of life in dementia: a study on proxy bias. BMC Med Res Methodol 2013;13:110.
26.
Jorm AF, Scott R, Jacomb PA: Assessment of cognitive decline in dementia by informant questionnaire. Int J Geriatr Psychiatry 1989;4:35-39.
27.
Jorm AF: The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): a review. Int Psychogeriatr 2004;16:275-293.
28.
Ippen CG, Olin JT, Schneider LS: Can caregivers independently rate cognitive and behavioral symptoms in Alzheimer's disease patients?: a longitudinal analysis. Am J Geriatr Psychiatry 1999;7:321-330.
29.
Koss E, Patterson MB, Ownby R, Stuckey JC, Whitehouse PJ: Memory evaluation in Alzheimer's disease: caregivers' appraisals and objective testing. Arch Neurol 1993;50:92-97.
30.
McLoughlin DM, Cooney C, Holmes C, Levy R: Carer informants for dementia sufferers: carer awareness of cognitive impairment in an elderly community-resident sample. Age Ageing 1996;25:367-371.
31.
Cacchione PZ, Powlishta KK, Grant EA, Buckles VD, Morris JC: Accuracy of collateral source reports in very mild to mild dementia of the Alzheimer type. J Am Geriatr Soc 2003;51:819-823.
32.
Nygaard HA, Naik M, Geitung JT: The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) is associated with informant stress. Int J Geriatr Psychiatry 2009;24:1185-1191.
33.
Kirkevold Ø, Selbæk G: The agreement between the MMSE and IQCODE tests in a community-based sample of subjects aged 70 years or older receiving in-home nursing: an explorative study. Dement Geriatr Cogn Disord Extra 2015;5:32-41.
34.
Stratford JA, LoGiudice D, Flicker L, Cook R, Waltrowicz W, Ames D: A memory clinic at a geriatric hospital: a report on 577 patients assessed with the CAMDEX over 9 years. Aust NZ J Psychiatry 2003;37:319-326.
35.
Waltrowicz W, Ames D, McKenzie S, Flicker L: Burden and stress on relatives (informal carers) of dementia sufferers in psychogeriatric nursing homes. Aust J Ageing 1996;15:115-118.
36.
Fernandez-Martinez M, Molano A, Castro J, Zarranz JJ: Prevalence of neuropsychiatric symptoms in mild cognitive impairment and Alzheimer's disease, and its relationship with cognitive impairment. Curr Alzheimer Res 2010;7:517-526.
37.
De Jonghe JF, Kat MG, Kalisvaart CJ, Boelaarts L: Neuropsychiatric Inventory Questionnaire (NPI-Q): a validity study of the Dutch form (in Dutch). Tijdschr Gerontol Geriatr 2003;34:74-77.
38.
Albert MS, DeKosky ST, Dickson D, Dubois B, Feldman HH, Fox NC, et al: 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 Dement 2011;7:270-279.
39.
Mackinnon A, Mulligan R: Combining cognitive testing and informant report to increase accuracy in screening for dementia. Am J Psychiatry 1998;155:1529-1535.
40.
Braekhus A, Ulstein I, Wyller TB, Engedal K: The Memory Clinic - outpatient assessment when dementia is suspected. Tidsskr Nor Laegeforen 2011;131:2254-2257.
41.
Greene JG, Smith R, Gardiner M, Timbury GC: Measuring behavioural disturbance of elderly demented patients in the community and its effects on relatives: a factor analytic study. Age Ageing 1982;11:121-126.
42.
Jorm AF: A short form of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): development and cross-validation. Psychol Med 1994;24:145-153.
43.
Lawton MP, Brody EM: Assessment of older people: self-maintaining and instrumental activities of daily living. Gerontologist 1969;9:179-186.
44.
Vittengl JR, White CN, McGovern RJ, Morton BJ: Comparative validity of seven scoring systems for the instrumental activities of daily living scale in rural elders. Aging Ment Health 2006;10:40-47.
45.
Kaufer DI, Cummings JL, Ketchel P, Smith V, MacMillan A, Shelley T, et al: Validation of the NPI-Q, a brief clinical form of the Neuropsychiatric Inventory. J Neuropsychiatry Clin Neurosci 2000;12:233-239.
46.
Folstein MF, Folstein SE, McHugh PR: ‘Mini-mental state'. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189-198.
47.
Engedal K, Gilje K, Laake K: Prevalence of dementia in a Norwegian sample aged 75 years and over and living at home. Compr Gerontol A 1988;2:102-106.
48.
O'Connor DW, Pollitt PA, Hyde JB, Fellows JL, Miller ND, Brook CP, et al: The reliability and validity of the Mini-Mental State in a British community survey. J Psychiatr Res 1989;23:87-96.
49.
Engedal K, Haugen P, Gilje K, Laake P: Efficacy of short mental tests in the detection of mental impairment in old age. Compr Gerontol A 1988;2:87-93.
50.
Mainland BJ, Amodeo S, Shulman KI: Multiple clock drawing scoring systems: simpler is better. Int J Geriatr Psychiatry 2014;29:127-136.
51.
Shulman KI: Clock-drawing: is it the ideal cognitive screening test? Int J Geriatr Psychiatry 2000;15:548-561.
52.
Ulstein I, Bruun Wyller T, Engedal K: The Relative Stress Scale, a useful instrument to identify various aspects of carer burden in dementia? Int J Geriatr Psychiatry 2007;22:61-67.
53.
Boyer F, Novella JL, Morrone I, Jolly D, Blanchard F: Agreement between dementia patient report and proxy reports using the Nottingham Health Profile. Int J Geriatr Psychiatry 2004;19:1026-1034.
54.
Chan SW: Family caregiving in dementia: the Asian perspective of a global problem. Dement Geriatr Cogn Disord 2010;30:469-478.
55.
Liew TM, Luo N, Ng WY, Chionh HL, Goh J, Yap P: Predicting gains in dementia caregiving. Dement Geriatr Cogn Disord 2010;29:115-122.
56.
Dubois B, Feldman HH, Jacova C, Hampel H, Molinuevo JL, Blennow K, et al: Advancing research diagnostic criteria for Alzheimer's disease: the IWG-2 criteria. Lancet Neurol 2014;13:614-629.
© 2015 S. Karger AG, Basel
2015
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.