EEG microstates as a “real time” feedback for rTMS treatment efficacy in MCI subjects

Abstract Background New treatments for the Alzheimer’s disease (AD) are evolving. There is a need for cheap, immediate and available treatment feedback biomarker which can demonstrate rapidly treatment success/failure. We used EEG microstates for this purpose while using repetitive Trans Magnetic stimulation (rTMS) treatment. Four types of microstates are identified according to EEG topography. They are characterized by their duration, frequent appearance and the transitions among the different microstates. The possibility of using microstates properties as a biomarker for rTMS treatment efficacy in mild cognitive impairment (MCI) subjects was explored. Methods We recruited 14 MCI subject to receive 16 rTMS sessions. EEG microstates were analyzed immediately before and after each treatment. We used 3 rTMS predefined protocols. The preferred protocol, for each patient, was selected using microstates duration. All patients performed a comprehensive neuro‐cognitive evaluation before rTMS treatment. 11 subjects completed a second neuro‐cognitive evaluation after treatment period ended. Results Microstates duration change was noticed before and after each rTMS treatment. Duration variation aided deciding which rTMS protocol is preferred in all participants. Moreover, new rTMS protocol was designed, for 3 patients, using microstates parameters. Cognitive performance was associated with microstate duration (p<0.05). Conclusions Microstates duration may serve as a “real time” treatment efficacy biomarker for MCI subjects. Further work should be done in order to validate this method.