Table 4.

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

Variable	Accuracy	Sensitivity	Specificity	PPV	NPV	Criterion score
VOT-SDvoiced	68 (n.s.)	50	78	55	74	0.03
nPVI-V	79	85	76	65	90	57
Distortion errors	84	60	97	93	82	11%
1 Hz–2 Hz	81	80	81	70	88	0.32
4 Hz–8 Hz	77	65	84	68	82	0.65
16 Hz–32 Hz	82	70	89	78	85	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.