Figure 4.

TMS motor mapping demonstrating cortical reorganization in children under 3 years of age. (A): TMS motor mapping in a 1.7-year-old male with history of refractory seizures involving left-sided tonic flexion with a cortical dysplasia in the medial frontal side of the right frontal lobe on the pre- and post-central gyrus. TMS localized left hand and forearm representation to the precentral gyrus. Additionally, MEPs in the hand and forearm muscles were elicited while stimulating the area of cortical dysplasia. No MEPs were elicited in the left lower extremity even at 100% of stimulator output. The child underwent surgical resection of the lesion. At 9 months follow up, he was seizure-free with intact left-hand function and mild left leg monoparesis. (B): A 2-year-old male with history of left hemisphere perinatal stroke and right hemiparesis presenting with refractory epilepsy. TMS motor mapping demonstrated no motor representation for right upper extremity in the left hemisphere. Instead, both left and right upper extremities were represented around the precentral gyrus in the right hemisphere. The left hemisphere is on the left side of the image.