Table 2.

Diagnostic parameters for GNP, WIV and the combination of the two metrics across AD, MCI, and HC

		HC versus AD	HC versus MCI	MCI versus AD
GNP	AUC (±95% CI)	0.99 (0.99–1.0)	0.94 (0.92–0.96)	0.81 (0.78–0.85)
	Sensitivity/Specificity	0.98/0.96	0.85/0.88	0.71/0.76
	Youden Index	0.94	0.73	0.47
	Cutoff#	−0.86	−0.52	−1.85
	Classification Accuracy	94%	85%	74%
WIV	AUC (±95% CI)	0.96 (0.95–0.98)	0.89 (0.86–0.91)	0.72 (0.68–0.76)
	Sensitivity/Specificity	0.88/0.93	0.79/0.83	0.64/0.73
	Youden Index	0.81	0.62	0.37
	Cutoff	1.26	1.09	1.64
	Classification Accuracy	90%	80%	70%
GNP+WIV	AUC (±95% CI)	0.99 (0.99–1.0)	0.95 (0.94–0.97)*	0.81 (0.78–0.85)
	Sensitivity/Specificity	0.98/0.97	0.85/0.93	0.71/0.76
	Youden Index	0.95	0.78	0.47
	Classification Accuracy	98%	94%	83%

Bold text indicated the best model for predicting group.

^*Overall AUC is significantly improved with the addition of a measure of variability (WIV).

^#GNP Cutoff scores are reported as a Z-score.

AD, Alzheimer’s disease; AUC, area under the curve; CI, confidence interval; GNP, global neuropsychological performance; HC, healthy participants; MCI, mild cognitive impairment; WIV, within-individual variability.