The Reliability and Validity of the Korean Instrumental Activities of Daily Living (K-IADL Sue J. Kang, M.S., Seong Hye Choi, M.D.*, Byung H. Lee, M.A., Jay C. Kwon, M.D., Duk L. Na, M.D., Seol-Heui Han M.D., Korean Dementia Research Group Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Neurology, College of Medicine, Inha University*, Department of Neurology, Chungbuk National University College of Medicine Background : The measurement of functional disabilities in patients with dementia is one of the essential parts of evaluation for dementia from the viewpoint of diagnosis and therapeutic intervention. Nevertheless, few standardized scales for the instrumental activities of daily living (IADL are available in Korea. The purpose of this study was to test the reliability and validity of the Korean IADL (K-IADL. M e t h o d s : K-IADL is comprised of 11 items that were selected by the Representative Committee of the Korean Dementia Research Group. These include: (1 shopping, (2 mode of transportation, (3 ability to handle finances, (4 house keeping, (5 preparing food, (6 ability to use a telephone, (7 responsibility for own medication, (8 recent memory, (9 hobbies, (10 watching television, and (11 fixing around the house. K-IADL was administered to informants of 114 dementia patients and age and sex matched 106 controls. The informants rated each item as follows: 0=normal, 1=with some assistance, 2=with much assistance, 3=unable to do, NA=not applicable. Results : Internal consistency (Cronbach s alpha=0.96 and the test-retest reliability(r=0.94 of K-IADL were significant. A principle component factor analysis extracted a single factor that accounted for 70.3% of the total variance (Eigenvalue: 7.74, and K-IADL was correlated significantly with other general cognitive indices, demonstrating good validity. With a cut-off point of 0.43, the K-IADL had a sensitivity of 83% and a specificity of 82% in the diagnosis of dementia. Conclusions : Our results showed that K-IADL could be a reliable and valid tool for the quantification of functional disabilities of Korean dementia patients. J Korean Neurol Assoc 20(1:8~14, 2002 Key Words : Dementia, K-IADL, Reliability, Validity Seol-Heui Han, M.D. 8 Copyright 2002 by the Korean Neurological Association
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Table 1. Demographic data of the subjects Dementia patients (n=114 Control subjects (n=106 p Age (yr: M±SD 68.75±6.67 66.97±7.02 ns Sex (male/female 43/71 41/65 ns Education (yr: M±SD 7.86±4.84 6.60±4.79 ns CDR (M±SD 1.14±0.65 0.16±0.25 <.001 GDS (M±SD 4.12±0.94 2.01±0.76 <.001 K-MMSE (M±SD 19.80±5.63 25.57±3.11 <.001 S-SDQ (M±SD 15.98±6.90 4.14±3.87 <.001 K-IADL (M±SD 1.20±0.80 0.21±0.28 <.001 CDR : Clinical Dementia Scale, GDS : Global Deterioration Scale, K-MMSE : Korean version of Mini-Mental State Examination, S- SDQ: Short Form of Samsung Dementia Questionnaire, K-IADL: Korean instrumental activities of daily living, M: mean, SD: standard deviation, yr: years, ns: not significant Table 2. Internal consistency for K-IADL K-IADL items Corrected item-total correlation Alpha if item deleted 1. Shopping.83.95 2. Travel (mode of transportation.81.95 3. Ability to handle finances.86.94 4. House keeping (use of electronic devices.67.95 5. Preparing food.85.94 6. Ability to use telephone.78.95 7. Responsibility for own medication.81.95 8. Recent memory.79.95 9. Hobbies.84.95 10. Watching TV.77.95 11. Fixing around the house.75.95 Alpha=.955, Standardized item alpha=.957 10 J Korean Neurol Assoc / Volume 20 / January, 2002
Table 3. Factor loading of K-IADL Factor 1 Factor Loading 1. Shopping.75 2. Travel (mode of transportation.72 3. Ability to handle finances.78 4. House keeping (use of electronic devices.52 5. Preparing food.78 6. Ability to use telephone.67 7. Responsibility for own medication.72 8. Recent memory.70 9. Hobbies.75 10. Watching TV.66 11. Fixing around the house.64 Eigenvalue 7.74 Variance explained (% 70.38 Figure 1. The receiver operating characteristic curve of the K-IADL Table 4. Correlation between K-IADL and cognitive measures (CDR, GDS, K-MMSE, S-SDQ CDR GDS K-MMSE S-SDQ K-IADL CDR 1.00 GDS 0.88* 1.00 K-MMSE -0.81* -0.79* 1.00 S-SDQ 0.81* 0.83* -0.73* 1.00 K-IADL 0.81* 0.79* -0.73* 0.84* 1.00 CDR: Clinical Dementia Scale, GDS: Global Deterioration Scale, K-MMSE: Korean version of Mini-Mental State Examination, S- SDQ: Short Form of Samsung Dementia Questionnaire, K-IADL: Korean instrumental activities of daily living, *p<.001 Table 5. Means and standard deviations of K-IADL for each CDR and GDS group CDR 0 CDR0.5 CDR1 CDR2 CDR3 p N(% 73(33.2 66(30.0 50(22.7 29(13.2 2(0.9 M±SD 0.11±0.15 0.52±0.42 1.05±0.61 2.08±0.56 2.14(0.83 <.001 GDS 1 GDS 2 GDS 3 GDS 4 GDS 5 GDS 6 p N(% 29(13.2 51(23.2 56(25.5 39(17.7 42(19.1 3(1.4 M±SD 0.05±0.10 0.16±0.17 0.52±0.42 0.91±0.50 1.86±0.67 2.20(0.60 <.001 CDR: Clinical Dementia Scale, GDS: Global Deterioration Scale J Korean Neurol Assoc / Volume 20 / January, 2002 11
Table 6. Not applicable items of K-IADL for each gender Not applicable items Total Male Female (n=220 (n=84 (n=136 p 1. Shopping 21 16 5 <.001 2. Travel (mode of transportation 9 4 5 ns 3. Ability to handle finances 18 10 8 ns 4. House keeping (use of electronic devices 32 29 3 <.001 5. Preparing food 68 63 5 <.001 6. Ability to use telephone 3 3 0. 7. Responsibility for own medication 4 3 1 ns 8. Recent memory 1 0 1. 9. Hobbies 36 10 26 ns 10. Watching TV 5 1 4 ns 11. Fixing around the house 60 20 40 <.01 ns: not significant 11. American Psychiatris Association. Diagnostic and Statistical Manual Disorders. 4th ed. Washinton, DC : American Psychiatric Association, 1994;143-146. 12. Juva K, Markela M, Erkinjuntti T, Sulkava R, Ylikoski R, Valvanne J, et al. Functional assessment scales in detecting dementia. Age Ageing 1997;26:393-400. 13. Curran S, Russell E, Burns A. Treatment of cognitive deficits in Alzheimer s disease. Prim Care Psychiatry 1 9 9 7 ; 3 : 1 5 1-1 6 1. 12 J Korean Neurol Assoc / Volume 20 / January, 2002
14. Jorm AF, Korten AE. Assessment of cognitive decline in elderly by informant interview. Br J Psychiatry 1 9 8 8 ; 1 5 2 : 2 0 9-2 1 3. 15. Rubin EH, Morris C, Grant EA, Vendega T. Very mild senile dementia of the Alzheimer s type I: Clinical assessment. Arch Neurol 1989;46:379-382. 16. Morris JC, McKeel DW, Storandt M, Rubin EH, Price JC, Grant EA, et al. Very mild Alzheimer s disease: Informantbased clinical, psychometric, and pathologic distinction form normal aging. N e u r o l o g y 1 9 9 1 ; 4 1 : 4 6 9-4 7 8. 17. Mahoney FI, Bathel DW. Function evaluation: the Bathel Index. Md Med J 1965;14:61-65. 18. Lawton MP, Brody EM. Assessment of older people: Self- Maintaining and instrumental activities of daily living. Gerontologist 1969;9:179-186. 19. Galasko D, Bennett D, Sano M, Ernesto C, Thomas R, Grundman M, et al. An inventory to assess activities of daily living for clinical trials in Alzheimer s disease. The Alzheimer s Disease Cooperative Study. Alzheimer Dis Assoc Disord 1997;11(suppl 2:S33-39. 10. Hindmarch I, Lehfeld H, Jongh PD, Erzigkeit H. The Bayer activities of daily living scale (B-ADL. D e m e n t Geriatr Cogn Disord 1998;9(suppl 2:20-26. 11. Pfeffer RI, Kurrosaki TT, Harrah CH, Chance JM, Filos S. Measurement of functional activities in older adult in the community. J Geront 1982;37:323-329. 12. Fillenbaum G. Screening the elderly: A brief instrumental activities of daily living measure. J Am Geriatr Soc 1 9 8 5 ; 3 3 : 6 9 8-7 0 5. 13. Loewenstein DA, Amigo E, Duara R, Guterman A, Hurwitz D, Berkowitz N, et al. A new scale for the assessment of functional status in Alzheimer s disease and related disorders. J Gerontol 1989;44:114-121. 14. Blessed G, Tomlinson BE, Roth M. The association between quantitative measures of dementia and of senile change in the cerebral grey matter of elderly subjects. Br J Psychiatry 1968;114:797-811. 15. Kartz S, Ford AB, Moskowitz RW, Jaffe MW. Studies of illness in the aged. The index of ADL: A standardized measure of biological and psychosocial function. J A M A 1963;185:914-919. 16. Lehfeld H, Reisberg B, Finkel S, Kanowski S, Wied V, Pittas J, et al. Informant-rated activities-of-daily-living (ADL assessments: results of a study of 141 items in the U.S.A., Germany, Russia, and Greece from the International ADL Scale Development Project. Alzheimer Dis Assoc D i s o r d 1997;11(suppl 4:S39-44. 17. Reisberg B. Functional assessment staging (FAST. Psychopharmacol Bull 1988;24:653-9. 18. Mckhann G, Drachman D, Folstein M, Katzman H, Price D, Stadian EM. Clinical diagnosis of Alzheimer s disease: report of the NINCDS-ADRDA Work Group under the auspices of department of health and human services task force on Alzheimer s disease. N e u r o l o g y 1 9 8 4 ; 3 4 : 9 3 9-944. 19. Chi HC, Victoroff JI, Margolin D, Jagust W, Shankle R, Katzman R. Criteria for the diagnosis of ischemic vascular dementia proposed by the state of California Alzeheimer s disease diagnostic and treatment centers. N e u r o l o g y 1992;42:473-480. 20. Morris JC. The clinical dementia rating (CDR; current version and scoring rules. Neurology 1993;43:2412-2414. 21. Reisberg B, Ferris SH, de Leon MJ, Crook T. Global Deterioration Scale (GDS. Psychopharmacol Bull 1 9 8 8 ; 2 4 : 6 6 1-6 6 3. 22. Kang Y, Na DL, Hahn S. A validity study on the Korean Mini-Mental State Examination (K-MMSE in dementia patients. J Korean Neurol Assoc 1 9 9 7 ; 1 5 : 3 0 0-3 0 7. 23. Choi SH, Na DL, Oh KM, Park BJ. A short form of Samsung Dementia Questionnaire (S-SDQ: development and cross-validation. J Korean Neurol Assoc 1999;17:253-258. J Korean Neurol Assoc / Volume 20 / January, 2002 13
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