Table 5.

Classification accuracy, sensitivity, specificity, and positive and negative predictive values (PPV, NPV, respectively) of each individual variable for the AOS-Aphasia group relative to the Aphasia Only group.

Variable	Accuracy	Sensitivity	Specificity	PPV	NPV	Criterion score
VOT-SDvoiced	63 (n.s.)	50	75	63	64	0.03
nPVI-V	75	85	67	68	84	56.8
Distortion errors	80	60	96	92	74	11%
1 Hz–2 Hz	75	70	79	74	76	0.33
4 Hz–8 Hz	71	60	79	71	70	0.40
16 Hz–32 Hz	80	70	88	82	78	0.24

Note. All variables yielded significant predictive models with the exception of the VOT-SD_voiced variable (n.s. = nonsignificant). The last column reports the criterion score for the given variable's sensitivity/specificity. The two predictors with highest values for each metric are presented in bold and underlined text.

AOS = apraxia of speech; VOT-SD = standard deviation of voice onset time; nPVI-V = normalized Pairwise Variability Index–Vowels.