Transcranial magnetic stimulation reveals an interhemispheric asymmetry of cortical inhibition in focal epilepsy
作者:
Paola Cicinelli,
Donatella Mattia,
Francesca Spanedda,
Raimondo Traversa,
Maria Marciani,
Patrizio Pasqualetti,
Paolo Rossini,
Giorgio Bernardi,
期刊:
NeuroReport
(OVID Available online 2000)
卷期:
Volume 11,
issue 4
页码: 701-707
ISSN:0959-4965
年代: 2000
出版商: OVID
关键词: Focal epilepsy;Inhibition;TCS
数据来源: OVID
摘要:
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.
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