OBJECTIVE: Approximately 30% of patients with newly diagnosed epilepsy do not respond to antiepileptic drugs (AEDs), but this is not predictable. We used transcranial magnetic stimulation to determine the effect of AEDs on cortical excitability in patients with epilepsy and correlated this with a successful response to treatment. METHODS: Ninety-nine drug-naïve patients with newly diagnosed epilepsy (55 idiopathic generalized epilepsy, 44 focal epilepsy) were evaluated. Motor threshold and cortical excitability on recovery curve analysis were measured before and 4 to 16 weeks after starting medication. After 1 year of treatment, 43 of 55 idiopathic generalized epilepsy and 26 of 44 focal epilepsy patients were seizure free. RESULTS: A decrease in cortical excitability occurred in the seizure-free group as indicated by an increase in motor threshold (p < 0.05) and intracortical inhibition on recovery curve analysis, maximum at the 250-millisecond interstimulus interval (p < 0.01) compared with pretreatment values. These changes were not present in the group with ongoing seizures. INTERPRETATION: Seizure freedom is marked by a reduction in transcranial magnetic stimulation measures of cortical excitability, evident shortly after beginning therapy. This virtual normalization of cortical excitability occurred regardless of the seizure characteristics or AED used. Failure to show this response to AED treatment may be valuable as an early predictor of pharmacoresistance in individual patients.
OBJECTIVE: Approximately 30% of patients with newly diagnosed epilepsy do not respond to antiepileptic drugs (AEDs), but this is not predictable. We used transcranial magnetic stimulation to determine the effect of AEDs on cortical excitability in patients with epilepsy and correlated this with a successful response to treatment. METHODS: Ninety-nine drug-naïve patients with newly diagnosed epilepsy (55 idiopathic generalized epilepsy, 44 focal epilepsy) were evaluated. Motor threshold and cortical excitability on recovery curve analysis were measured before and 4 to 16 weeks after starting medication. After 1 year of treatment, 43 of 55 idiopathic generalized epilepsy and 26 of 44 focal epilepsypatients were seizure free. RESULTS: A decrease in cortical excitability occurred in the seizure-free group as indicated by an increase in motor threshold (p < 0.05) and intracortical inhibition on recovery curve analysis, maximum at the 250-millisecond interstimulus interval (p < 0.01) compared with pretreatment values. These changes were not present in the group with ongoing seizures. INTERPRETATION:Seizure freedom is marked by a reduction in transcranial magnetic stimulation measures of cortical excitability, evident shortly after beginning therapy. This virtual normalization of cortical excitability occurred regardless of the seizure characteristics or AED used. Failure to show this response to AED treatment may be valuable as an early predictor of pharmacoresistance in individual patients.
Authors: Mouhsin M Shafi; Marine Vernet; Debby Klooster; Catherine J Chu; Katica Boric; Mollie E Barnard; Kelsey Romatoski; M Brandon Westover; Joanna A Christodoulou; John D E Gabrieli; Susan Whitfield-Gabrieli; Alvaro Pascual-Leone; Bernard S Chang Journal: Ann Neurol Date: 2015-01-29 Impact factor: 10.422
Authors: Prisca R Bauer; Annika A de Goede; William M Stern; Adam D Pawley; Fahmida A Chowdhury; Robert M Helling; Romain Bouet; Stiliyan N Kalitzin; Gerhard H Visser; Sanjay M Sisodiya; John C Rothwell; Mark P Richardson; Michel J A M van Putten; Josemir W Sander Journal: Brain Date: 2018-02-01 Impact factor: 13.501
Authors: Mustafa Q Hameed; Sameer C Dhamne; Roman Gersner; Harper L Kaye; Lindsay M Oberman; Alvaro Pascual-Leone; Alexander Rotenberg Journal: Curr Neurol Neurosci Rep Date: 2017-02 Impact factor: 5.081
Authors: Mouhsin M Shafi; Susan Whitfield-Gabrieli; Catherine J Chu; Alvaro Pascual-Leone; Bernard S Chang Journal: J Vis Exp Date: 2016-11-13 Impact factor: 1.355