'RMT-FINDER' : AN AUTOMATED PROCEDURE TO DETERMINE THE RESTING MOTOR THRESHOLD FOR TRANSCRANIAL MAGNETIC STIMULATION

Background: Transcranial Magnetic Stimulation (TMS) studies identify the Resting Motor Threshold (RMT) to calibrate stimulation intensity. However, this procedure is time-consuming and subject to variability. We developed an automated procedure to improve the efficiency and standardization of RMT determination.
New method: We developed an algorithm that measures MEP amplitudes and automatically adjusts stimulation intensity to determine the RMT. Experiment 1 compared this automated method with the manual procedure in terms of reliability and equivalence. Experiment 2 developed a “Fast” automated process, assessing it against both the manual and initial automated procedures.
Results: Across both experiments the automated approach demonstrated excellent test-retest reliability and strong agreement with the manual method (Intraclass Correlation Coefficients ≥0.95), giving estimates of RMT equivalent to those of manual measurements within ±3% MSO, with the majority of comparisons within ±2% MSO. Experiment 2 optimized the procedure, allowing empirical determination of the RMT in an average of <3 minutes with only 33-34 pulses.
Comparison with existing methods: ‘RMT-Finder’ provides a reliable and time-efficient alternative to manual approaches. To the best of our knowledge RMT-Finder presents the first ‘closed-loop feedback’ approach to identify the RMT without manual intervention. This procedure can improve standardization and reproducibility in TMS studies.
Conclusions: Automating RMT assessment allows rapid and highly reproducible assessment of this standard TMS measurement, making it viable for inclusion in routine clinical applications that require standardized procedures.