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

Area of Science:

• Neuroscience
• Biomedical Engineering
• Clinical Research

Background:

• Transcranial Magnetic Stimulation (TMS) relies on Resting Motor Threshold (RMT) for calibrating stimulation intensity.
• Current manual RMT determination is time-consuming and prone to variability.
• There is a need for improved efficiency and standardization in RMT assessment.

Purpose of the Study:

• To develop and validate an automated procedure for determining the Resting Motor Threshold (RMT).
• To enhance the efficiency, reliability, and standardization of RMT measurement in TMS studies.
• To provide a viable alternative for routine clinical applications.

Main Methods:

• An algorithm was developed to automatically measure motor evoked potential (MEP) amplitudes and adjust stimulation intensity for RMT determination.
• Two experiments were conducted: Experiment 1 compared the automated method with manual procedures for reliability and equivalence.
• Experiment 2 introduced a "Fast" automated process and assessed its performance against manual and initial automated methods.

Main Results:

• The automated approach demonstrated excellent test-retest reliability and strong agreement with manual methods (ICC ≥0.95).
• RMT estimates from the automated method were statistically equivalent to manual measurements (within ±3% MSO).
• An optimized automated procedure determined RMT in under 3 minutes using approximately 33-34 pulses.

Conclusions:

• Automated RMT assessment offers a rapid and highly reproducible method for TMS.
• This automated procedure, 'RMT-Finder', provides a reliable and time-efficient alternative to manual approaches.
• The automation enhances standardization and reproducibility, making it suitable for routine clinical TMS applications.