Changes in cerebral cortex activity during a simple motor task after MRgFUS treatment in patients affected by essential tremor and Parkinson's disease: a pilot study using functional NIRS

Objective: Magnetic Resonance Imaging-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive thermal ablation method that involves high-intensity Focused Ultrasound Surgery (FUS) and Magnetic Resonance Imaging (MRI) for anatomical imaging and real-time thermal mapping. This technique is widely employed for the treatment of patients affected by essential tremor (ET) and Parkinson's disease (PD). In the current study, functional Near-Infrared Spectroscopy (fNIRS) was used to highlight hemodynamics changes in cerebral cortex activity, during a simple hand motor task, i.e., unimanual left and right finger-tapping, in ET and PD patients. Approach: All patients were evaluated before, one week and one month after MRgFUS treatment. Main results: fNIRS revealed cerebral hemodynamic changes one week and one month after MRgFUS treatment, especially in the ET group, that showed a significant clinical improvement in tremor clinical scores. Significance: To our knowledge, our study is the first that showed the use of fNIRS system to measure the cortical activity changes following unilateral Ventral Intermediate Nucleus (VIM) thalamotomy after MRgFUS treatment. Our findings showed that therapeutic MRgFUS promoted the remodeling of neuronal networks and changes in cortical activity in association with symptomatic improvements.