Expression of praxis induction on cortical excitability in juvenile myoclonic epilepsy.
This study aimed to evaluate the effects of praxis induction on sensorimotor cortical and transcallosal excitability in juvenile myoclonic epilepsy (JME).



A total of 36 subjects (18-62years) were included. The JME group was screened by video-electroencephalography neuropsychological protocol and divided into 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 (SEPs).



Motor and transcallosal excitabilities 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 the P27 component of the non-dominant hemisphere (p=0.03, Cohen's d=0.98), N35 in the dominant hemisphere (p=0.04, Cohen's d=0.96), and P27-35 interpeak amplitude in both somatosensory cortices of the JME-PI group (p=0.03, Cohen's d=0.96; p=0.02, Cohen's d=1.05) when compared with healthy controls. Giant SEPs were observed in two (16.7%) and five (50%) patients of the JME-WI and JME-PI groups, respectively. Cortical latencies did not reveal differences.



Praxis induction was associated with enhanced excitability in the somatosensory cortex of JME patients.



These findings may help clarifying the less favorable therapeutic response in the JME-PI group and indicate identifying praxis induction as an important determinant in differentiating between JME patients.
Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil. Electronic address: dourado@unifesp.br.
Marcos
M
Vidal-Dourado
Department of Neurology and Neurosurgery, Division of Neurology, Section of Clinical Neurophysiology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Karlo Faria
KF
Nunes
Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Mirian Salvadori Bittar
MS
Guaranha
Department of Neurology and Neurosurgery, Division of Neurology, Section of Clinical Neurophysiology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Lydia Maria Pereira
LM
Giuliano
Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Elza Márcia Targas
EM
Yacubian
Department of Neurology and Neurosurgery, Division of Neurology, Section of Clinical Neurophysiology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Gilberto Mastrocola
GM
Manzano
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020190:Myoclonic Epilepsy, Juvenile / Q000503:physiopathology*; D011597:Psychomotor Performance; D012018:Reflex; D050781:Transcranial Magnetic Stimulation
Idiopathic generalized epilepsy; Reflex epilepsies; Somatosensory evoked potential; Transcallosal excitability; Transcranial magnetic stimulation