A Study on the Reliability and Validity of Seoul-Instrumental Activities of Daily Living(S-IADL)

Abstract

OBJECTIVES: Seoul-Instrumental Activities of Daily Living (S-IADL) was developed to assess elderly person's instrumental everyday activities. This study aims to develop standardized IADL assessment scale and to confirm the reliability and validity of the S-IADL. METHODS: The 336 controls were included in standardization study. Reliability and validity of S-IADL were tested by 72 Alzheimer's disease patients and 72 controls matched to age, sex, and education. We also conducted Receiver Operating Characteristics curve for sensitivity and specificity of S-IADL. RESULTS: Because of positively skewed distribution of S-IADL, standardization data were presented using 1SD and 2SD value. Internal consistency, test-retest reliability, and interrater reliability were statistically significant. Principal axis factoring analysis revealed two factors that accounted for 59.95% of the total variance, and second factor was items sensitive to sex (3.preparing food/cooking, 4.household chores). S-IADL was correlated significantly with other standardized cognitive measures, demonstrating good convergent validity. With a cut-off point of 8, the S-IADL had a sensitivity of 83.3% and specificity of 93.1% in the diagnosis of dementia. Also, with a 2SD standardized data, sensitivity was 81.9% and specificity was 93.1%. CONCLUSION: Our study showed that the S-IADL could be a reliable and valid tool for the assessment of functional disabilities of Korean dementia patients. Particularly, S-IADL had higher sensitivity and specificity than other IADL instruments, suggesting that it is useful to early detection of dementia.