I`m choosing between active active and resting motor threshold for our rTMS study in patients. Do you know any study where their relationship has been comprehensively studied? I found quite variable reports - from 120% to 130-140%. My doubt is that AMT is much more difficult to get in patients, so would be enough to rely on RMT percentage if the previous studies used AMT? Thank you advance!
If rTMS will be delivered during activation of your target muscle, AMT may be more informative. Otherwise, the obvious value in AMT is ease of hot spot localization at lower stimulation. So, if AMT instead renders calibration more difficult, why not use RMT, more accurately modeling the state under which rTMS will be delivered?
Thank you for your answer! Do you know if anybody really compared them in a special study using nTMS?
May depend on type of patients and any medication that they are taking. For example, RMT may be more difficult to find on epileptic patients who are medicated compared to those who have stopped medication. Most likely the choice of stimulation intensity percentages above threshold would be limited by patients with high thresholds.
Paula Rowe thanks for answering! They are stroke patients, and the target is contralesional hemis[here, so it should not be too high RMT. The thing is that I`d like to use a protocol from another study where they used AMT.
Maria Nazarova I have an interest in stroke but have only used single or paired pulse TMS for epileptic patients and healthy controls.
A number of studies have used rTMS over contralesional hemisphere at 80%, 90% or 100% RMT at low frequencies.
For example see Sandrini M, Cohen LG. Noninvasive brain stimulation in neurorehabilitation. Handb Clin Neurol. 2013;116:499–524. doi:10.1016/B978-0-444-53497-2.00040-1
No doubt there are, but I'm afraid I'm not familiar with similar studies using AMT.
Good luck with your research.
I have seen that 70% AMT is equal to 100% RMT, but do not rememmber which paper.
Hope this help.
"2007, Hanajima et al., Comparison of different methods for estimating motor threshold with TMS "
Hi, Maria, I found out your question! Did you figure out that? Also, when you apply rTMS using AMT the subject need to do muscle contraction? I mean in the moment of rTMS.
Hi, Gleydciane Alexandre Fernandes ! Not 100%=)), but I orient to around 70-80%, as we piloted it ourselves, also the paper recommended above is useful. As you do AMT based rTMS no contraction is usually used, while the question about the activity-dependent AMT-based stimulation is interesting by itself. You may want to see
Hebbian-Type Primary Motor Cortex Stimulation: A Potential Treatment of Impaired Hand Function in Chronic Stroke Patients by Revill et al.
70% RMT is close to 80% AMT.
Goldsworthy MR, Pitcher JB, Ridding MC. The application of spaced theta burst protocols induces long-lasting neuroplastic changes in the human motor cortex. Eur J Neurosci. 2012 Jan;35(1):125-34.
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