Table 4. Sensitivity, specificity of each instrument completed by informants at different cut-off scores for discriminating dementia (normal vs. dementia).

Cut-off score		Normal (n = 200)	Dementia (n = 170)	Sensitivity (95% CI)	Specificity (95% CI)	AUC (95% CI)
i-KDSQ-C						0.92 (0.89–0.95)
	< 9	185	36	0.79 (0.72–0.85)	0.93 (0.88–0.96)
	≥ 9a	15	134
	< 6	158	26	0.85 (0.78–0.90)	0.79 (0.73–0.84)
	≥ 6	42	144
i-AD8						0.93 (0.90–0.95)
	< 3	177	29	0.83 (0.76–0.88)	0.89 (0.83–0.93)
	≥ 3a	23	141
	< 2	161	17	0.90 (0.84–0.94)	0.81 (0.74–0.86)
	≥ 2	39	153
i-SMCQ						0.92 (0.89–0.95)
	< 5	166	21	0.88 (0.82–0.92)	0.83 (0.77–0.88)
	≥ 5a	34	149
	< 6	173	32	0.81 (0.74–0.87)	0.87 (0.81–0.91)
	≥ 6	27	138

AUC = area under the curve, CI = confidence interval, i-KDSQ-C = informant-completed Korean Dementia Screening Questionnaire-Cognition, i-AD8 = informant-completed Alzheimer Disease 8, i-SMCQ = informant-completed Subjective Memory Complaints Questionnaire.

^aOptimal cut-off by Youden's index.