Authors :
Presenting Author: Bahram SarviZargar, MSc – Corewell Health
Jeremy Gurumendi, BS – Corewell Health
Erin Skrzypek, BS – Corewell Health
Veikko Jousmaki, PhD – Aalto University
Ammar kheder, MD – Corewell Health
Angel Hernandez, MD – Johns Hopkins All Children´s Hospital, Johns Hopkins University School of Medicine
Paul Ferrari, PhD – Corewell Health
Rationale:
Functional mapping using magnetoencephalography is a standard part of the pre-surgical workup for pediatric epilepsy and oncology patients undergoing surgical evaluation. Routinely, motor mapping is performed to assess the relative localization of motor eloquent cortex to epilepsy regions or tumor location. However, very young children or those with development delay may require sedation to comply with the functional exam precluding active participation in a motor task. While previous studies of passive motor mapping have shown motor specific activation patterns, there has not been any studies in sedated children validating passive motor mapping.
Methods:
17 children ages 3 -14 years and one adult aged 43 underwent passive MEG motor mapping of bilateral upper extremities under conscious sedation using dexmedetomidine. Two methods of passive movement were utilized. Either the patients index finger was manually moved to press a button response pad or the patient was automatically articulated via a custom non-ferrous device driven by a pneumatic system. There were at least 100 repetitions for each extremity. Source localization was performed using a standard equivalent dipole model, or in the case of dipole failure, an LCMV beamformer. Source localization of motor activation was compared to that of electrical median nerve stimulation.
Results: Successful somatosensory median nerve localization was accomplished bilaterally in all patients. Motor mapping was successful in 29 of 36 hemispheres, 80% . A beamformer was required to localize motor activity in 5 cases. Furthermore, in all successfully mapped hemispheres, motor related activity localized to the precentral gyrus in the vicinity of the hand region.
Conclusions:
Passive motor mapping can be performed in sedated individuals using MEG. The localization results of this study suggest that passive motor mapping in sedation provides additional functional information above passive somatosensory mapping.
Funding: None