Fetal Vibroacoustic Stimulation in Computerized Cardiotocographic Analysis: The Role of Short-Term Variability and Approximate Entropy

Table 6

Sensitivity and specificity analysis.

(a) High-risk pregnancies

	Positive perinatal outcome	Negative perinatal outcome
Positive VAS Test	31	8
Negative VAS Test	49	33

Sensitivity = 31/(31 + 49) = 0,39 = 39%.
95% confidence interval = 0,39 ± 1,96 √ 0,39 · (1 − 0,39)/(31 + 49) = 0,2831–0,4969.
Specificity = 33/(8 + 33) = 0,8 = 80%.
95% confidence interval = 0,8 ± 1,96 √ 0,8 · (1 − 0,8)/(8 + 33)= 0,6776–0,9224.

(b) Low-risk pregnancies

	Positive perinatal outcome	Negative perinatal outcome
Positive VAS Test	32	4
Negative VAS Test	54	5

Sensitivity = 32/(32 + 54) = 0,37 = 37%.
95% confidence interval = 0,37 ± 1,96 √ 0,37 · (1 − 0,37)/(32 + 54) = 0,27–0,47.
Specificity = 5/(4 + 5) = 0,55 = 55%.
95% confidence interval = 0,55 ± 1,96 √ 0,55 · (1− 0,55)/(4 + 5) = 0,23–0,87.