Neuronal and Cerebrovascular Response to tDCS in Multiple Sclerosis: A Simultaneous tDCS-MRI Study

Motivation: The cerebral metabolic underpinnings of tDCS, both during the stimulation itself and as result of repeated sessions are still not fully understood. Goal(s): To quantify the immediate tDCS effects (simultaneous) using real-time tDCS-MRI and treatment-related effects (cumulative after repeated sessions) in multiple sclerosis (MS) patients. Approach: MS patients had tDCS-MRI performed at baseline and after 20 tDCS treatment sessions. Imaging measurements were acquired pre-, during- (2.0mA left frontal anodal) and post-tDCS. Results: During tDCS, at baseline, we observed a 7.6% increase in cerebral metabolic rate of oxygen (CMRO2). tDCS-treatment induced a 9.6% increase of the pre-tDCS CMRO2 levels. Impact: The significant increase in neuronal metabolism following both real-time and repeated tDCS treatment in MS patients offers valuable insights into the biophysiological mechanisms regarding acute and cumulative tDCS effects, informing future clinical applications in MS and other neurodegenerative diseases.