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Table 3 Measurements of motor cortex parameters using transcranial magnetic stimulation (n = 47)

From: Association of anxiety with intracortical inhibition and descending pain modulation in chronic myofascial pain syndrome

Cortical excitability measures   
  Before QST evoked pain After QST evoked pain
  Mean±SD Median (Q25, Q75) Mean±SD Median (Q25, Q75)
Motor Threshold (MT) 42.65 (7.39) 41 (37.5, 46) ---- -----
Motor evoked potential (mV) 1.74 (0.71) 1.53 (1.27, 2.20) 2.13 (0.93) 1.93 (1.58, 2.58)
Intracortical Facilitation (ratio: ICF/test stimulus) 1.16 (0.42) 1.11 (1, 1.23) 1.25 (0.59) 1.15 (0.92, 1.44)
Short Interval Intracortical Inhibition (ratio: SICI/test stimulus) 0.32 (0.14) 0.28 (0.22, 0.35) 0.34 (0.19) 0.29 (0.21, 0.43)
Cortical Silent Period (CSP) 65.42 (19.64) 66.25 (47.9, 79.31) 66.16 (20.16) 68.30 (50.59, 81.71)
  1. (Motor evoked potential: MEP); Interquartile interval (Q); Intra-cortical inhibition (ICI) expresses the relationship between the amplitude of wave and motor evoked potentials (relative amplitude, express in%), at inter-stimuli intervals (ISIs) of 2 ms with paired-pulse. The first is a sub-threshold stimulus [80% of the rest motor threshold (rMT)] followed by the second one which is a suprathreshold stimulus (130% rMT). (B) Cortical silent period (CSP) expressed in milliseconds (ms); (C) Motor-evoked potentials (MEP) expressed in mV, evoked by a stimulus of 130% the intensity of the rMT, and should have peak-to-peak MEP amplitude of at least 1 mV.