What is the role of motor evoked potentials (MEPs) in the treatment of epilepsy?

Updated: Aug 20, 2019
  • Author: Jasvinder Chawla, MD, MBA; Chief Editor: Selim R Benbadis, MD  more...
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Answer

Answer

Some believe that TMS induces seizures when used to evaluate patients with partial epilepsy. TMS has actually appeared to be poorly epileptogenic at low frequencies of stimulation (induction rate in epileptic patients: 0-92%). To what extent low-rate TMS may induce seizures, even in susceptible individuals, remains questionable. Although rTMS can provoke seizures, the effect depends on the individual (epileptic vs nonepileptic), antiepileptic treatment, and stimulus type (intensity-frequency).

Therapeutic benefit of rTMS

Intracortical inhibition is reduced in epileptic patients. Because low-rate rTMS can increase intracortical inhibition, this paradigm was used as a treatment in patients with intractable epilepsy. A substantial reduction of seizure frequency was reported in an open study.

Determination of language dominance before surgical procedures

Induction of speech arrest after stimulation of the dominant hemisphere is possible, but the reported success rate ranges from between 50-100% of subjects. This seems to depend at least partly on the stimulation technique (ie, coil type) used, but it remains to be clarified fully in further studies.


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