Effect of epilepsy on primary hand motor map: A single center study using fMRI and TMS
Abstract number :
1059
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2020
Submission ID :
2423392
Source :
www.aesnet.org
Presentation date :
12/7/2020 1:26:24 PM
Published date :
Nov 21, 2020, 02:24 AM
Authors :
Mitchell Batschelett, Rhodes College and Le Bonheur Neuroscience Institute; Basanagoud Mudigoudar - University of Tennessee Health Science Center, Le Bonheur Children’s Hospital; Savannah Gibbs - Le Bonheur Children's Hospital Neuroscience Institute; Asim
Rationale:
Transcranial Magnetic Stimulation (TMS) and functional MRI (fMRI) are used routinely to obtain preoperative cortical motor maps in patients of various ages. Cortical motor maps obtained using TMS and fMRI, especially primary hand motor cortex (M1hand) maps, follow a fairly well-defined spatial representation localized to the precentral gyrus (PrG). However, in patients with structural brain lesions that are within or close to primary motor cortex, the M1hand may reorganize to juxtalesional or contralateral cortices, depending on various factors. Although the reorganizational consequences of injury to the primary motor cortex are reasonably understood, the reorganizational implications of epilepsy are still unclear. In this study, we used both TMS and fMRI to localize M1hand in patients with lesional or non-lesional focal and generalized epilepsy. Furthermore, we examined the magnitude of motor cortex distortion by observing the location of M1hand in relation to the PrG.
Method:
We retrospectively reviewed charts of all patients who underwent motor mapping of both the hemispheres using TMS, with or without fMRI. Patients with lesions within or close to the primary motor cortex or the pyramidal tracts were excluded. The center of gravity (CoG) of M1hand representation was calculated for each patient. We compared M1hand location in lesional focal, non-lesional focal, and generalized epilepsy. Statistical analyses were conducted using Chi-Square testing.
Results:
Data from 76 patients (age 5 to 44 years) with epilepsy who underwent motor mapping of both hemispheres using TMS with or without fMRI were included in the final analysis, for a total of 240 hemispheres mapped with either modality. No significant effect was observed on M1hand localization in either the affected or unaffected hemispheres within any type of epilepsy. PrG was the most prominent localization area for the M1hand in all groups. Furthermore, TMS and fMRI found similar patterns of topography with high concurrence rates (81%).
Conclusion:
The results showed that M1hand localization remains unaffected in various types of epilepsy. Our study suggests little to no structural or functional change to the M1hand as a consequence of a host of epileptic disorders. It also demonstrates high concurrence rates between TMS and fMRI in localization of primary hand motor area.
Funding:
:Neuroscience Scholar award by Rhode College and Le Bonheur Neuroscience Institute
Neurophysiology