Reliability and validity of a short form of the Severe Impairment Battery in Korean Alzheimer's disease patients

AbstractThe objective of this study was to evaluate the reliability and validity of a short form of the Severe Impairment Battery (SIB) for a Korean population. Eighty‐four Alzheimer's disease patients with Clinical Dementia Rating (CDR) stages 2 (n = 32) or 3 (n = 52) and scores of less than 15 on the Korean version‐Mini Mental State Examination (K‐MMSE) participated in this study. Seventeen of the patients were men and 67 were women, and the mean age was 75 (SD = 10.4). Cronbach's coefficient alpha of the shortened SIB (SIB‐S) was 0.93, and the item‐total correlation was significant. Test–retest correlation for the total SIB‐S score and subscale scores was significant, with the exception of the ‘orienting to name’ subscale. Construct validity was confirmed by evaluating the correlation between the SIB‐S and the SIB, K‐MMSE, CDR, and S‐ADL; Spearman correlation coefficients were 0.96, 0.88, −0.67, and −0.63, respectively, which were found to be significant. The difference in the total SIB‐S score and its subscale scores between the CDR 2 and CDR 3 groups was significant, except for the ‘orienting to name’ subscale. More severely demented patients also showed a wide range of the SIB‐S score. Finally, the diagnostic accuracy of the SIB‐S was high (AUC = 89.5%) in the differentiation of the CDR 2 and 3 patients. The sensitivity and specificity of the SIB‐S were 91% and 80%, respectively, when the cut‐off score was 32.5. Our results indicate that the SIB‐S is a reliable and valid instrument for evaluating patients with severe dementia in the Korean population. Copyright © 2006 John Wiley & Sons, Ltd.