'RMT-Finder': An automated procedure to determine the Resting Motor Threshold for Transcranial Magnetic Stimulation

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.

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.

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 statistically 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 min with only 33-34 pulses.

'RMT-Finder' provides a reliable and time-efficient alternative to manual approaches. This procedure can improve standardization and reproducibility in TMS studies.

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.