Comparison of Rossini–Rothwell and adaptive threshold‐hunting methods on the stability of TMS induced motor evoked potentials amplitudes

Abstract

Several methods can be used to determine the resting motor threshold (RMT) and by that recording transcranial magnetic stimulation (TMS) induced motor evoked potentials (MEPs). However, no research has compared the test retest reliability of these methods. Thus, the aim of this study was to determine intra- and inter-session reliability of Rossini-Rothwell (R-R) and parameter estimation by sequential testing (PEST) methods on TMS-induced MEPs and comparison of these two methods on RMT. Twelve healthy individuals participated in this study three times (T1, T2 and T3) over two days. TMS was applied using both R-R and PEST to estimate RMT and average of 25 MEPs were acquired at each of the three time points. The intra-class correlation coefficient indicated high intra-session reliability in the MEP amplitudes for both methods (0.79 and 0.88, R-R and PEST respectively). The RMT and MEP amplitudes had higher inter-session reliability in both methods (0.99 and 0.998, R-R and PEST respectively; 0.84 and 0.76, R-R and PEST respectively). There was no significant difference between methods for RMT at both T1 (maximum stimulator output of R-R vs. PEST, 33.7% ± 7.7% vs. 33.8% ± 7.6%, p = 0.75) and T3 (maximum stimulator output of R-R vs. PEST, 33.5% ± 7.3% vs. 33.7% ± 7.3%, p = 0.19). There was a significant positive correlation between the methods' estimates of RMT, with PEST requiring significantly fewer stimuli. This study shows that the R-R and PEST methods have high intra-and inter-session reliability and the same precision, with PEST having the advantage over R-R in speed of estimation of RMT.

Transcranial Random Noise Stimulation Acutely Lowers the Response Threshold of Human Motor Circuits

“…CC-BY-NC-ND 4.0 International license perpetuity. It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted February 24, 2021. ; https://doi.org/10.1101/2020.10.07.329813 doi: bioRxiv preprint (Kobayashi and Pascual-Leone 2003;Nitsche et al 2005;Hallett 2007;Livingston and Ingersoll 2008;Rossi et al 2009;Ngomo et al 2012;Hinder et al 2014;Schambra et al 2015;Davila-Pérez et al 2018;Dissanayaka et al 2018;Jannati et al 2019). For all experiments we ran additional control analyses by re-calculating MEP probabilities for other amplitude criteria, i.e., MEP amplitudes larger than or equal to 0.03, 0.04, 0.06 and 0.07 mV to ensure that the observed effects are not purely driven by the definition of the RMT.…”

“…In fact, the absolute changes in RMT were relatively small (even though statistical effect sizes were medium to large). This can be partly attributed to the fact that we aimed to modulate resting motor threshold, which is one of the most robust and reliable TMS measurements (Ngomo et al 2012;Dissanayaka et al 2018). Indeed, RMT has rarely been modulated by other forms of electrical stimulation (Nitsche et al 2005), including long-lasting effects of tRNS (Terney et al 2008).…”

Short-interval intracortical inhibition as a function of inter-stimulus interval: Three methods compared

“…T-SICIs and T-SICIp are not the only possible methods of measuring SICI as a change in stimulus for a constant response, rather than a change in response for a constant stimulus. Just as resting motor threshold (RMT) can be measured in different ways [12,13], so can the threshold for a conditioned response. For example, adaptive threshold hunting has been used by Cirillo and colleagues [14], using a 'maximum-likelihood parameter estimation by sequential testing' (PEST) [15,16].…”

Transcranial Random Noise Stimulation acutely lowers the response threshold of human motor circuits

“…In fact, the absolute changes in RMT were relatively small (even though statistical effect sizes were medium to large). This can be partly attributed to the fact that we aimed to modulate resting motor threshold, which is one of the most robust and reliable TMS measurements (Kobayashi and Pascual-Leone 2003;Hallett 2007;Livingston and Ingersoll 2008;Rossi et al 2009;Ngomo et al 2012;Hinder et al 2014;Schambra et al 2015;Davila-Pérez et al 2018;Dissanayaka et al 2018;Jannati et al 2019). In fact, RMT has rarely been modulated by other forms of electrical stimulation (Nitsche et al 2005), including long-lasting effects of tRNS (Terney et al 2008).…”

“…We decided to investigate RMT modulation since it allows us to assess the individual membrane excitability of the corticospinal tract neurons (Kobayashi and Pascual-Leone 2003;Hallett 2007;Rossi et al 2009). RMT serves as one of the most robust TMS measurements (Kobayashi and Pascual-Leone 2003;Nitsche et al 2005;Hallett 2007;Livingston and Ingersoll 2008;Rossi et al 2009;Ngomo et al 2012;Hinder et al 2014;Schambra et al 2015;Davila-Pérez et al 2018;Dissanayaka et al 2018;Jannati et al 2019). For all experiments we ran additional control analyses by re-calculating MEP probabilities for other amplitude criteria, i.e., MEP amplitudes larger than or equal to 0.03, 0.04, 0.06 and 0.07 mV to ensure that the observed effects are not purely driven by the definition of the RMT.…”