Early and late intracortical inhibition in juvenile myoclonic epilepsy

Paolo Manganotti, Luigi Giuseppe Bongiovanni, Gianpietro Zanette, Antonio Fiaschi

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: We investigated 15 patients with juvenile myoclonic epilepsy (JME) by subjecting them to single and paired transcranial magnetic stimulation to test the hypothesis that motor cortical inhibition may be abnormal in this form of benign epilepsy. Methods: Different conditioning paradigms of paired transcranial magnetic stimulation were used with interstimulus intervals (ISIs) of varying lengths (1 to 400 milliseconds) to investigate changes in balance between excitatory and inhibitory intracortical circuits. Results: Motor evoked potential (MEP) inhibition at ISIs of 1 to 4 milliseconds was significantly lower in JME patients than in age-matched healthy controls (p <0.001), whereas no significant differences in MEP inhibition were noted at long ISIs (100 to 150 milliseconds). This pattern was observed in both hemispheres in seven of seven patients studied bilaterally and was present in both treated and untreated patients. There were no group differences between JME patients and controls in intracortical facilitation, motor threshold, MEP amplitude, and cortical silent period. Conclusions: We documented a different pattern of MEP inhibition in JME patients, suggesting impaired functioning of inhibitory interneuronal circuits, which may account for the hyperexcitability of the motor system in this form of epilepsy.

Original languageEnglish
Pages (from-to)1129-1138
Number of pages10
JournalEpilepsia
Volume41
Issue number9
Publication statusPublished - 2000

Keywords

  • Cortical inhibition
  • Epilepsy
  • GABA inhibition
  • Magnetic stimulation
  • Motor cortex

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

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