FUNCTIONAL REORGANIZATION OF THE FACE MOTOR AREA IN PATIENTS WITH EPILEPTOGENIC LESIONS OF THE CENTRAL REGION
Abstract number :
B.05
Submission category :
Year :
2003
Submission ID :
3590
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Alexandre Carpentier, Stephane Clemenceau, Stephane Lehericy, Remy van Effenterre, Michel Baulac Departments of Neurosurgery, Neuroradiology and Epilepsy, Hopital de la Pitie-Salpetriere, Universite Paris VI, Paris, France
Slowly evolving brain damage such as low grade tumor may result in plastic changes of cortical motor networks. The nature of these plastic changes and the factors related to these changes are largely unknown in patients with brain tumor although their knowledge may have important functional value. Functional magnetic resonance imaging (fMRI) is a powerful tool in the evaluation of motor cortex functionality in the pre-operative planning of surgical procedures in and around the Rolandic region. We used fMRI to determine the factors related to reorganization of motor circuits in the presence of a brain epileptogenic lesions.
10 normals and 76 patients (45 low grade astrocytomas, 20 high grade gliomas, 11 congenital vascular malformations) were studied using fMRI with a face motor paradigm. Activation maps were constructed for each subject, and changes in position/amplitude/surface of the motor activation on the lesion side were compared with the activation pattern obtained in the hemisphere contralateral to the lesion. Histology, lesion location, primary face motor area infiltration, mass effect, epilepsy, and facial palsy were studied in terms of impact on cortical motor fMRI interhemispheric asymmetry index using a multivariate statistical analysis. In the motor cortex, a laterality index (LI) was calculated as follows: LI=[(L-R)/(L+R)] with L and R being the numbers of activated voxels in the left and right hemispheres, respectively.
Asymmetric pixel count in motor cortex activation was observed in patients presenting with face area infiltration (p[lt]0.0001), mass effect (p[lt]0.002) and high epileptic seizures frequency (p=0.0035). Histology, age, handedness, lesion side, epilepsy duration and age of epilepsy onset had no impact on cortical activation. Only 3 patients had pre-operative facial palsy. Post-operative facial palsy occurred in 6 patients and resolved completely within 15 ([plusmn]30) days.
Three main factors were associated with reorganization of the primary face motor area: motor cortex infiltration, mass effect and epileptic seizures frequency. Post-operative findings show that functional motor recovery occurs even in patients with direct lesion of the primary motor face area. This study supports the specificity of epilepsy as a cortical plasticity inductor.
[Supported by: Assistance Publique - Hopitaux de Paris - INSERM EMI 0224 and EPI007]