{"doi":"10.1016/j.brs.2024.04.008","title":"Together towards more accessible, standardized TMS protocols: Reply to Sorkhabi and Leedham","abstract":"We would like to thank Sorkhabi and Leedham for their careful consideration of our recent transcranial magnetic stimulation (TMS) study [[1]Wang Y. Vora I. Huynh B.P. Picard-Fraser M. Daneshzand M. Nummenmaa A. Kimberley T.J. Coils are not created equal: effects on TMS thresholding.Brain Stimul: Basic, Translational, and Clinical Research in Neuromodulation. 2024; 17: 1-3Google Scholar] and the Brain Stimulation Editors for this opportunity to clarify our findings further. Our study was motivated by a notable lack of clarity in many repetitive TMS (rTMS) papers regarding the issue of re-thresholding between non-cooled (typically used for hotspot search and motor thresholding, i.e., “assessment”) and cooled coils (typically for rTMS or theta-burst stimulation, i.e., “treatment”). That is, “if I am using coil-stimulator A for assessment, do I need to re-threshold with coil-stimulator B for treatment?” Given that the re-thresholding process can be time intensive, the empirical interchangeability or a constant change factor between assessment and treatment coils would be a pragmatic benefit to clinical use or time-strapped experiments. Specifically, we found that with identical stimulator and pulse delivery, Magstim Alpha and Remote coils are interchangeable with each other but not with AirFilm, while MagVenture C–B60 can interchange with Cool-B65. A set of conversion factors within Magstim was proposed, which needs additional validation. We also measured the magnetic field pulses of additional coil-stimulator setups beyond the default, because these alternative setups and their impact on TMS pulses are often unclear. As reinforced in Sorkhabi and Leedham's reply, it is essential to account for differences in coil-stimulator designs, the convention of which can be arbitrary and manufacturer-specific. Importantly, all coils and stimulators we tested behaved consistently from a technical standpoint, as their product design states. However, if not considered and reported, seemingly mundane choices (e.g., using a different TMS system to replicate a paper's protocol, switching between non-cooled and cooled coils on the same stimulator, changing the pulse waveform without inverting the current direction, etc.) can impact appropriate treatment dosing and repeatability between studies. To demonstrate potential dosing errors by a naive operator using all default settings, we decided to threshold with Alpha and Remote on a monophasic stimulator and AirFilm on a biphasic stimulator [[1]Wang Y. Vora I. Huynh B.P. Picard-Fraser M. Daneshzand M. Nummenmaa A. Kimberley T.J. Coils are not created equal: effects on TMS thresholding.Brain Stimul: Basic, Translational, and Clinical Research in Neuromodulation. 2024; 17: 1-3Google Scholar]. The significantly lower rMT using Alpha/Remote vs. AirFilm cannot be attributed to pulse waveform differences alone because the Alpha/Remote-associated monophasic pulses typically elicit a higher rMT compared to biphasic pulses regardless of current direction ([[2]Sommer M. Alfaro A. Rummel M. Speck S. Lang N. Tings T. Paulus W. Half sine, monophasic and biphasic transcranial magnetic stimulation of the human motor cortex.Clin Neurophysiol. 2006; 117: 838-844Crossref PubMed Scopus (152) Google Scholar], albeit in this paper, it was assessed with a bent, rather than flat, figure-of-8 coil). The primary factor is likely the higher absolute maximum stimulator output (MSO) for the monophasic (BiStim2/2002) stimulator, which was confirmed with our magnetic field measurements below (Fig. 1a vs 1c; also see MSO reported in [[3]Sorkhabi MM Wendt K O’Shea J Denison T Pulse width modulation-based TMS: Primary motor cortex responses compared to conventional monophasic stimuli.Brain Stimul. 2022; 15: 980-983Abstract Full Text Full Text PDF Scopus (4) Google Scholar]) and found in an earlier model [[4]Kammer T. Beck S. Thielscher A. Laubis-Herrmann U. Topka H. Motor thresholds in humans: a transcranial magnetic stimulation stu","journal":"Brain stimulation","year":2024,"id":497113,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9691,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":297460,"name":"Aapo Nummenmaa","orcid":"0000-0002-6452-7958","position":1,"is_corresponding":false},{"id":341449,"name":"Teresa J. Kimberley","orcid":"0000-0001-6397-4054","position":2,"is_corresponding":false},{"id":1117236,"name":"Yuchao Wang","orcid":"0000-0001-9871-3006","position":0,"is_corresponding":true}],"reference_count":9,"raw_metadata":null,"created_at":"2026-07-19T02:09:30.779495Z","pmid":"38685264","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}