Expression of praxis induction on cortical excitability in juvenile myoclonic epilepsy

Publication date: Available online 12 April 2016
Source:Clinical Neurophysiology
Author(s): Marcos Vidal-Dourado, Karlo Faria Nunes, Mirian Salvadori Bittar Guaranha, Lydia Maria Pereira Giuliano, Elza Márcia Targas Yacubian, Gilberto Mastrocola Manzano
ObjectiveTo evaluate the effects of praxis induction on sensorimotor cortical and transcallosal excitability in juvenile myoclonic epilepsy (JME).MethodsThirty-six subjects (18-62 years) were included. JME group was screened by video-electroencephalography neuropsychological protocol and divided as JME without praxis induction [JME-WI (n=12)], JME with praxis-induced seizures or epileptiform discharges [JME-PI (n=10)] and healthy controls (n=14). Motor and somatosensory cortical excitability and transcallosal pathways were evaluated through single pulse transcranial magnetic stimulation (sTMS) and somatosensory evoked potentials (SEP).ResultsMotor and transcallosal excitability tested with sTMS were not different in the motor dominant or non-dominant hemisphere among groups. Significant differences were found in cortical SEP amplitudes in P27 component in non-dominant hemisphere (p=0.03, Cohen's d=0.98), N35 in dominant hemisphere (p=0.04, Cohen's d=0.96) and P27-35 interpeak amplitude in both somatosensory cortex of JME-PI group (p=0.03, Cohen's d=0.96; p=0.02, Cohen's d=1.05) when comparing to healthy controls. Giant SEPs were observed in two (16.7%) patients of JME-WI and five (50%) of JME-PI group. Cortical latencies did not reveal differences.ConclusionsPraxis induction was associated with enhanced excitability in somatosensory cortex of JME patients.SignificanceThese findings may help clarifying the less favorable therapeutic response in JME-PI and point to identifying praxis induction as important determinant in differentiating between JME patients.



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