Transcranial magnetic stimulation reveals an interhemispheric asymmetry of cortical inhibition in focal epilepsy

Paola Cicinelli, Donatella Mattia, Francesca Spanedda, Raimondo Traversa, Maria Grazia Marciani, Patrizio Pasqualetti, Paolo Maria Rossini, Giorgio Bernardi

Research output: Contribution to journalArticlepeer-review

Abstract

Transcranial magnetic stimulation (TCS) was applied to both hemispheres of 16 patients affected by criptogenic focal epilepsy to evaluate the interhemispheric symmetry of the motor cortex excitability. The amplitude of the motor evoked potentials (MEPs) and the duration of the post-MEP silent period (SP) were measured at threshold (THR) and at increasing TCS stimulation intensities. The THR was significantly higher in patients than in 16 age-matched control subjects (p <0.01). No interhemispheric differences were found in MEP amplitude. In controls the correlation between SP duration and increasing TCS stimulus intensity was linear with a symmetrical progression of the SP duration over the two hemispheres. In patients this linear SP progression was lacking on the 'epileptic' hemisphere: the SP duration did not increase following TCS > 40% above THR, indicating abnormal interhemispheric asymmetry. This finding suggests a selective dysfunction of inhibition in the epileptic hemisphere as signaled by an abnormal SP duration in response to progressively higher TCS intensities. (C) 2000 Lippincott Williams and Wilkins.

Original languageEnglish
Pages (from-to)701-707
Number of pages7
JournalNeuroReport
Volume11
Issue number4
Publication statusPublished - Mar 20 2000

Keywords

  • Focal epilepsy
  • Inhibition
  • TCS

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Transcranial magnetic stimulation reveals an interhemispheric asymmetry of cortical inhibition in focal epilepsy'. Together they form a unique fingerprint.

Cite this