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Table 3 Sensitivity and specificity of peroneal CMAP reduction to diagnose critical illness myopathy and/or neuropathy

From: Simplified electrophysiological evaluation of peripheral nerves in critically ill patients: the Italian multi-centre CRIMYNE study

  

Time of development

Sensitivity

Specificity

  

ICU day

(True-positive rate)

(True-negative rate)

 

Number (%)

Median (IQR)

  

1. One peroneal CMAP reduced according to criterion A

64 (69.6)

3 (2–5)

28/28 = 100%

28/64 = 44%

2. One peroneal CMAP reduced according to criterion B

49 (53.3)

4 (2–7)

28/28 = 100%

43/64 = 67%

3. Both peroneal CMAPs reduced according to criterion A

26 (28.3)

6 (3–10)

21/28 = 75%

59/64 = 92%

4. One peroneal CMAP reduced according to criterion A plus the

contralateral peroneal CMAP reduced according to criterion B

23 (25.0)

6 (3–10)

21/28 = 75%

62/64 = 97%

5. Both peroneal CMAPs reduced according to criterion B

16 (17.4)

6 (3.5–10)

16/28 = 57%

64/64 = 100%

  1. Criterion A = CMAP amplitude reduced by more than 25% of its initial value (at ICU admission) but less than two standard deviations (SDs) of its normal value. Criterion B = CMAP reduced by more than 2 SDs of its normal value. Note that the five categories are not mutually exclusive (for example, the 16 patients in category 5 are also included in category 2). CMAP, compound muscle action potential; ICU, intensive care unit; IQR, interquartile range.