Discrepancies between preoperative stereoencephalography language stimulation mapping and intraoperative awake mapping during resection of focal cortical dysplasia in eloquent areas.
OBJECTIVE
To compare the reliability of preoperative stereoencephalography (SEEG) and intraoperative electrostimulation regarding functional mapping, and to select the indication for surgery for focal cortical dysplasia (FCD) in language areas.


METHODS
The authors present the case of a 21-year-old, right-handed female, suffering from chronic pharmacologically resistant epilepsy since the age of 8. MRI showed a subcortical hypersignal on FLAIR and T(2) sequences at the posterior end of the left superior temporal sulcus compatible with an FCD. SEEG invasive monitoring was performed to precisely identify the epileptogenic zone (EZ) and for functional language mapping.


RESULTS
The stimulation of the contacts implicated in the EZ through SEEG leads induced language disturbances, which were not reproducible. Surgery was performed under local anesthesia with awake corticosubcortical mapping. Direct intraoperative stimulation in the EZ, including FCD, did not induce language disturbances. Thus, EZ could be removed completely without any postoperative language deficit.


CONCLUSIONS
The present case suggests that when language disturbances which occur during invasive SEEG functional mapping, in eloquent areas, are not reproducible, resection can be considered using intraoperative electrical mapping, without inducing permanent language impairment. This may be explained by a certain degree of plasticity and reshaping of functional areas associated with a congenital lesion and chronic epilepsy.
Gil Robles
Santiago
S
Department of Neurosurgery, Gui de Chauliac Hospital, CHU Montpellier, Montpellier, France.
Gelisse
Philippe
P
Vergani
Francesco
F
Moritz-Gasser
Sylvie
S
Rigau
Valerie
V
Coubes
Philippe
P
Crespel
Arielle
A
Duffau
Hugues
H
D000513:Alpha Rhythm / Q000379:methods*; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology / Q000601:surgery; D005260:Female; D006801:Humans; D007802:Language; D054220:Malformations of Cortical Development / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D016343:Monitoring, Intraoperative / Q000379:methods*; D011300:Preoperative Care / Q000379:methods*; D055815:Young Adult