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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)

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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.