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Table 5 SSEPs findings in different myoclonus subtypes according to anatomical classification

From: Electrophysiological characteristics and anatomical differentiation of epileptic and non-epileptic myoclonus

  Cortical (N = 10) Subcortical (N = 12) Cortical–subcortical (N = 28) Control (N = 30) P P1 P1 P3
Right median nerve
 N20 amplitude 2.1 ± 0.6 1.9 ± 0.7 1.9 ± 0.8 2.2 ± 0.8 0.62 0.86 0.25 0.25
 N20 latency 23.2 ± 0.1 23.2 ± 0.1 23.3 ± 0.2 23.3 ± 0.2 0.28 0.08 0.536 0.96
 P24 amplitude 20.9 ± 27.5 7.2 ± 1.9 3.29 ± 2.4 2.7 ± 0.8 0.005*  < 0.001*  < 0.001* 0.004*
 P24 latency 24.8 ± 0.6 25.2 ± 0.8 25.1 ± 0.3 25.2 ± 0.2 0.3 0.14 0.864 0.61
 N33 amplitude 24.5 ± 30.8 9.7 ± 1.8 4.4 ± 2.9 3.9 ± 1.3 0.004* 0.006*  < 0.001* 0.005*
 N33 latency 33.5 ± 0.2 34.1 ± 0.5 34.1 ± 0.4 34.1 ± 0.2 0.003*  < 0.001* 0.89 0.87
 P24–N33 complex amp 45.4 ± 58.3 16.5 ± 3.4 7.7 ± 5.2 5.8 ± 1.9 0.004*  < 0.001*  < 0.001* 0.002*
Left median nerve
 N20 amplitude 2 ± 0.7 2.1 ± 0.7 1.9 ± 0.7 2.1 ± 0.7 0.76 0.89 0.25 0.48
 N20 latency 23.2 ± 0.1 23.3 ± 0.1 23.2 ± 0.1 23.2 ± 0.2 0.05 0.14 0.54 0.86
 P24 amplitude 19.4 ± 22.5 7.3 ± 2.3 3.3 ± 1.9 2.4 ± 0.9 0.002* 0.041*  < 0.001* 0.034*
 P24 latency 25.2 ± 0.9 24.9 ± 0.2 25.1 ± 0.1 25.2 ± 0.2 0.39 0.83 0.86 0.11
 N33 amplitude 23.5 ± 26.5 8.8 ± 2.69 4.6 ± 2.2 3.5 ± 1.3 0.002* 0.041*  < 0.001* 0.029*
 N33 latency 33.6 ± 0.6 33.97 ± 0.52 34.1 ± 0.3 34.1 ± 0.2 0.104 0.040* 0.895 0.746
 P24–N33 complex amp 42.9 ± 49 16.1 ± 4.9 7.9 ± 4 5.7 ± 2 0.002* 0.040*  < 0.001* 0.024*
 EEG Spike/polyspike wave complex 10 (100%) 4 (33.3%) 18 (64.3%) 0 0.005*  < 0.001  < 0.001  < 0.001
  1. P: all patients according to anatomical subtypes vs control (one-way Anova test); P1: cortical myoclonus vs control (Student t-test); P2: subcortical myoclonus vs control (Student t-test); P3: cortical–subcortical myoclonus vs control (Student t-test)