ASSESSMENT OF THE INSTRUMENTAL ACTIVITIES OF DAILY LIVING IN MILD COGNITIVE IMPAIRMENT AND DEMENTIA DUE TO ALZHEIMER'S DISEASE: DIAGNOSTIC ACCURACY OF THE SERBIAN VERSION OF THE AMSTERDAM IADL QUESTIONNAIRE

Abstract

To establish a diagnosis of dementia, it is necessary, in addition to cognitive impairment, to prove the existence of a disorder of instrumental activities of daily living (IADL). The Amsterdam IADL Questionnaire is a reliable instrument translated into different languages. This study aims to assess the diagnostic accuracy of the Serbian version of the Amsterdam IADL Questionnaire. The study included 75 patients with mild cognitive impairment (MCI) and dementia due to Alzheimer's disease. The questionnaire was scored using the weighted average (WA) and item response theory (IRT) scoring method. Diagnostic accuracy was examined using receiver–operating characteristic (ROC) curves. The area under the curves (AUC) was calculated with 95% confidence intervals (CI). The correlation between IRT and WA scores was strong and significant (r=-0.980, p<0.001). The AUC for the IRT scores of A-IADL-Q was 0.832 (95% CI: 0.729 to 0.909), while the AUC for the WA scores of A-IADL-Q was 0.848 (95% CI: 0.746 to 0.920). Both were significantly different from the AUC of 0.5 (p<0.001). There was no significant difference between the AUCs of IRT and WA scoring (z=1.157; p=0.247). Cutoffs and the highest combination of sensitivity and specificity for the IRT (sensitivity 0.767; specificity 0. 844) and WA (sensitivity 0.744; specificity 0. 844) scores of A-IADL-Q were calculated. We have shown that A-IADL-Q has moderate diagnostic accuracy in differentiating dementia and MCI. This instrument can be used in combination with cognitive measures to diagnose dementia in its early stages.