Multimodal assessment of motor pathways and intracortical connections in functional hemispherectomy.

Pilato, Fabio; Pravatà , Emanuele; Battaglia, Domenica; Calandrelli, Rosalinda; Massimi, Luca; Di Rocco, Concezio; Di Lazzaro, Vincenzo

PURPOSE For selected children with medically intractable epilepsy, hemispherectomy can be an excellent treatment option and its efficacy in achieving seizure freedom or reduction in seizure frequency has been shown in several studies, but patients' selection could not be straightforward and often it is taken on subjective basis. We described a multimodal approach to assess patient eligible for hemispherectomy and possibly predicting post-surgical outcomes. METHODS We describe pre- and post-surgical clinical features along with neuroradiological results by magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), MR-tractography (MRT), and neurophysiological study by single and paired pulses transcranial magnetic stimulation (TMS) in a child with cerebral palsy with epileptic encephalopathy, eligible for epilepsy surgery. RESULTS Presurgical TMS evaluation showed a lateralization of motor function on the left motor cortex for both arms, and results were confirmed by MRI studies. Interestingly, after surgery, both epilepsy and motor performances improved and TMS showed enhancement of intracortical inhibition and facilitation activity. CONCLUSION Functional hemispherectomy is an effective treatment for drug-resistant epilepsy, and multimodal presurgical assessment may be a useful approach to guide surgeons in selecting patients. Moreover, pre- and post-surgical evaluation of these patients may enhance our understanding of brain plasticity phenomena.