Short Description
Transcranial magnetic stimulation (TMS) is used to investigate pathophysiological changes in the motor system in a number of neurological conditions including epilepsy. A coil is placed over the scalp, and a changing current within it generates a magnetic field, which in turn induces a current within the motor cortex. Corticospinal motorneurons are excited to firing potential via interneurons triggered by the current, and this activity can be recorded as a motor evoked potential (MEP) from a small hand muscle (Fig. 115-1 ). The minimum stimulus intensity required to evoke an MEP of 50–100 μV peak–peak amplitude in more than 50% of 10–20 trials is termed the motor threshold for that hemisphere.
Experimental set up of transcranial magnetic stimulation and motor evoked potential
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Abbreviations
- AEDs:
-
Anti-epileptic drugs
- CR:
-
Conditioning response
- IGE:
-
Idiopathic generalized epilepsy
- ISIs:
-
Interstimulus intervals
- MEP:
-
Motor evoked potential
- TMS:
-
Transcranial magnetic stimulation
- TR:
-
Test response
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Macdonell, R.A.L., Badawy, R.A.B. (2010). Transcranial Magnetic Stimulation in Epilepsy. In: Panayiotopoulos, C.P. (eds) Atlas of Epilepsies. Springer, London. https://doi.org/10.1007/978-1-84882-128-6_115
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DOI: https://doi.org/10.1007/978-1-84882-128-6_115
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