Recruitment of Contralateral Supplementary Motor Area in Functional Recovery Following Medial Frontal Lobe Surgery: An fMRI Case Study

BACKGROUND AND OBJECTIVE: Supplementary motor area (SMA) syndrome, an executive disorder with motor and speech dysfunctions, is rather unpredictable with typically a complete or almost complete functional recovery within weeks or months. Compensatory mechanisms are associated with contralateral cortical recruitment of the lateral premotor circuitry. We sought to investigate the role of healthy SMA for motor recovery following surgery in the medial frontal lobe. METHODS: A 48-year-old right-handed man presented with focal motor seizures. The diagnostic work-up revealed a low-grade glioma at the superior frontal gyrus. The patient was operated on with intraoperative monitoring of motor pathways, and resection was taken to the functional boundaries. RESULTS: Postoperatively, the patient experienced a typical SMA syndrome that almost completely resolved in the long term. Motor recovery occurred concurrently with a shift of SMA activation to the healthy hemisphere together with an increased lateral premotor circuitry, especially for the hand map. CONCLUSION: Our results confirm brain remodeling of the lateral premotor cortex, as previously described, and indicate that functional improvement is also paralleled with a shift of SMA activation toward the healthy hemisphere.