Defective interhemispheric inhibition in drug-treated focal epilepsies

Gionata Strigaro, Erica Matino, Lina Falletta, Chiara Pizzamiglio, Giacomo Tondo, Radwa Badawy, Roberto Cantello

Risultato della ricerca: Contributo su rivistaArticolo in rivistapeer review

Abstract

Background Focal epilepsies (FEs) arise from a lateralized network, while in generalized epilepsies (GEs) there is a bilateral involvement from the outset. Intuitively, the corpus callosum is the anatomical substrate for interhemispheric spread. Objective We used transcranial magnetic stimulation (TMS) to explore whether there are any physiological differences in the corpus callosum of drug-treated patients with FE and those with genetic GE (GGE), compared to healthy subjects (HS). Methods TMS was used to measure the interhemispheric inhibition (IHI) from right-to-left primary motor cortex (M1) and viceversa in 16 patients with FE, 17 patients with GGE and 17 HS. A conditioning stimulus (CS) was given to one M1 10 and 50 ms before a test stimulus delivered to the contralateral M1. Motor evoked potentials (MEPs) were analysed both as a function of the side of stimulation and of the epileptic focus (left-right). Results In HS, IHI was reproducible with suppression of MEPs at ISIs of 10 and 50 ms. Similar effects occurred in GGE patients. FE patients behaved differently, since IHI was significantly reduced bilaterally. When FE patients were stratified according to the side of their epileptic focus, the long-ISI IHI (=50 ms) appeared to be defective only when the CS was applied over the “focal” hemisphere. Conclusions FE patients had a defective inhibitory response of contralateral M1 to inputs travelling from the “focal” hemisphere that was residual to the drug action. Whilst IHI changes would not be crucial for the GGE pathophysiology, they may represent one key factor for the contralateral spread of focal discharges, and seizure generalization.

Lingua originaleInglese
pagine (da-a)579-587
Numero di pagine9
RivistaBrain Stimulation
Volume10
Numero di pubblicazione3
DOI
Stato di pubblicazionePubblicato - mag 2017

Fingerprint

Entra nei temi di ricerca di 'Defective interhemispheric inhibition in drug-treated focal epilepsies'. Insieme formano una fingerprint unica.

Cita questo