Table 2.

Classification results of MCI subtypes: features measured at baseline, wave-2 and longitudinally are used and compared.

Task	No. of minority class	No. of majority class	Method	Accuracy (%)	Sensitivity (%)	Specificity (%)	AUC
aMCI vs. CN	aMCI = 42	CN = 115	Baseline	0.64	0.42	0.71	0.68
			Wave-2	0.81*	0.68	0.85	0.74
			Longitudinal	0.73	0.53	0.80	0.75
naMCI vs. CN	naMCI = 27	CN = 115	Baseline	0.67	0.37	0.75	0.57
			Wave-2	0.65	0.30	0.74	0.58
			Longitudinal	0.70	0.23	0.82	0.60
naMCI vs. aMCI	naMCI = 27	aMCI = 42	Baseline	0.77*	0.70*	0.82	0.84*
			Wave-2	0.71	0.57	0.82	0.70
			Longitudinal	0.61	0.40	0.78	0.71

wave-2, 2-year follow-up; MCI, mild cognitive impairment; CN cognitively normal; aMCI, amnestic MCI; naMCI, non-amnestic MCI; AUC, area under the receiver operating characteristic curve.

^*Significantly different from the method using longitudinal features; results are from t-test (p < 0.05).