TABLE 3

Diagnostic Performance Measures at Different Probability Thresholds

Risk ThresholdSensitivity (95% CI)Specificity (95% CI)PPV (95% CI)NPV (95% CI)Balanced Accuracy (95% CI)
0.200.73 (0.62–0.82)0.82 (0.73–0.89)0.76 (0.68–0.83)0.79 (0.72–0.84)0.78 (0.71–0.83)
0.350.70 (0.59–0.80)0.91 (0.84–0.96)0.87 (0.78–0.93)0.79 (0.73–0.84)0.82 (0.76–0.87)
0.500.62 (0.51–0.72)0.96 (0.90–0.99)0.93 (0.83–0.97)0.76 (0.70–0.80)0.81 (0.74–0.86)
0.650.51 (0.40–0.62)0.98 (0.93–1.00)0.96 (0.84–0.99)0.71 (0.66–0.75)0.77 (0.70–0.83)
0.800.18 (0.10–0.28)0.99 (0.05–1.00)0.94 (0.67–0.99)0.60 (0.57–0.62)0.63 (0.55–0.70)
  • Obtained from the multivariate model including both clinical and EEG predictor variables. For example, when using the risk threshold of 20%, all patients with a probability > 0.2 will be scored as cases, and the accuracy statistics are computed on the basis of these data. Thresholds are chosen on a cost-benefit analysis of false-positive and false-negative findings and can be changed according to the clinical situation. Sensitivity and specificity were corrected for prevalence of epilepsy in our training cohort.27 To assess the potential value of the model in less straightforward cases, we separately assessed the model in a subgroup of children of the validation cohort in whom diagnosis remained uncertain after first evaluation and where ancillary investigations or follow-up were needed for a definitive diagnosis.