Objective: To examine the validity and reliability of the application of Chinese version of AD8 among patients with Alzheimer's disease (AD), and to explore the discriminative properties of AD8 including score boundaries, sensitivity and specificity in differentiating AD and normal controls.
Methods: A total of 240 subjects were recruited, including 75 cognitively intact subjects as normal control and 165 patients with AD. Normal control and patients with AD were assessed with Clinical Dementia Rating (CDR), Mini-Mental State Examination (MMSE), and Clock Drawing Test (CDT). All informed normal controls and informants of patients with AD were asked about Chinese version of AD8, among which, 158 informants of patients with AD received AD8 examination again.
Results: (1) The Cronbach alpha for Chinese version of AD8 was 0.78. The intraclass correlation coefficient (ICC) of retest reliability was 0.96 (P < 0.01). (2) The correlation coefficients between each item of AD8 ranged from 0.36 to 0.69 (P < 0.01). Chinese version of AD8 total scores were strongly positively correlated with CDR global score (r = 0.82, P < 0.01), and CDR-SB(r = 0.80, P < 0.01), and negatively correlated with the total score of MMSE (r = -0.75, P < 0.01) and CDT (r = -0.53, P < 0.01). (3) For discrimination between normal controls and patients with AD, the AUC was 0.93. Using a cutoff of 2 or greater on Chinese version of AD8 to discriminate dementia, the sensitivity was 93.9%, and specificity was 76.0%.
Conclusion: Chinese version of AD8 is a brief and sensitive screening measure with good validity and reliability.