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Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation protocols on human motor cortex excitability.
Clin Neurophysiol. 2008 Jun; 119(6):1393-9.CN

Abstract

OBJECTIVE

Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation (rTMS) protocols on human motor cortex excitability.

METHODS

Stimulation of dominant hand abductor digiti minimi muscle representation of motor cortex in nine healthy right-handed subjects utilising two different MagPro stimulators to generate TMS pulses of distinct monophasic, half sine and biphasic shape with anteriorly or posteriorly directed current flow, measuring resting and active motor threshold and motor-evoked potential (MEP) amplitude. Comparison of two different conventional rTMSs and eight different theta burst stimulation (TBS) protocols.

RESULTS

Continuous TBS (cTBS) yielded an inhibition, and intermittent TBS (iTBS) a facilitation of MEP amplitudes. These effects were not significantly influenced by waveform or current orientation. Compared to conventional rTMS paradigms, neither cTBS nor iTBS showed significantly stronger effects. In addition and confirming earlier findings, the asymmetric monophasic pulse and a posteriorly directed current flow yielded a higher threshold than all other TMS types. The less asymmetric half-sine pulse had a lower threshold for postero-anterior current than in the opposite direction. The biphasic stimuli yielded the lowest motor threshold particularly with an antero-posterior current direction.

CONCLUSIONS

TBS did not depend on current direction or on pulse configuration in this sample of healthy subjects. In addition, TBS effect size was not clearly superior to conventional rTMS protocols.

SIGNIFICANCE

This systematic comparison of three waveforms, two current directions and two different interventional protocols allows a better understanding of the mechanisms of TMS on human motor cortex.

Authors+Show Affiliations

Department of Clinical Neurophysiology, University of Göttingen, Robert-Koch-Street 40, 37075 Göttingen, Germany.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18400556

Citation

Zafar, Noman, et al. "Comparative Assessment of Best Conventional With Best Theta Burst Repetitive Transcranial Magnetic Stimulation Protocols On Human Motor Cortex Excitability." Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology, vol. 119, no. 6, 2008, pp. 1393-9.
Zafar N, Paulus W, Sommer M. Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation protocols on human motor cortex excitability. Clin Neurophysiol. 2008;119(6):1393-9.
Zafar, N., Paulus, W., & Sommer, M. (2008). Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation protocols on human motor cortex excitability. Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology, 119(6), 1393-9. https://doi.org/10.1016/j.clinph.2008.02.006
Zafar N, Paulus W, Sommer M. Comparative Assessment of Best Conventional With Best Theta Burst Repetitive Transcranial Magnetic Stimulation Protocols On Human Motor Cortex Excitability. Clin Neurophysiol. 2008;119(6):1393-9. PubMed PMID: 18400556.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation protocols on human motor cortex excitability. AU - Zafar,Noman, AU - Paulus,Walter, AU - Sommer,Martin, Y1 - 2008/04/08/ PY - 2007/11/19/received PY - 2008/01/22/revised PY - 2008/02/13/accepted PY - 2008/4/11/pubmed PY - 2008/7/11/medline PY - 2008/4/11/entrez SP - 1393 EP - 9 JF - Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology JO - Clin Neurophysiol VL - 119 IS - 6 N2 - OBJECTIVE: Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation (rTMS) protocols on human motor cortex excitability. METHODS: Stimulation of dominant hand abductor digiti minimi muscle representation of motor cortex in nine healthy right-handed subjects utilising two different MagPro stimulators to generate TMS pulses of distinct monophasic, half sine and biphasic shape with anteriorly or posteriorly directed current flow, measuring resting and active motor threshold and motor-evoked potential (MEP) amplitude. Comparison of two different conventional rTMSs and eight different theta burst stimulation (TBS) protocols. RESULTS: Continuous TBS (cTBS) yielded an inhibition, and intermittent TBS (iTBS) a facilitation of MEP amplitudes. These effects were not significantly influenced by waveform or current orientation. Compared to conventional rTMS paradigms, neither cTBS nor iTBS showed significantly stronger effects. In addition and confirming earlier findings, the asymmetric monophasic pulse and a posteriorly directed current flow yielded a higher threshold than all other TMS types. The less asymmetric half-sine pulse had a lower threshold for postero-anterior current than in the opposite direction. The biphasic stimuli yielded the lowest motor threshold particularly with an antero-posterior current direction. CONCLUSIONS: TBS did not depend on current direction or on pulse configuration in this sample of healthy subjects. In addition, TBS effect size was not clearly superior to conventional rTMS protocols. SIGNIFICANCE: This systematic comparison of three waveforms, two current directions and two different interventional protocols allows a better understanding of the mechanisms of TMS on human motor cortex. SN - 1388-2457 UR - https://www.unboundmedicine.com/medline/citation/18400556/Comparative_assessment_of_best_conventional_with_best_theta_burst_repetitive_transcranial_magnetic_stimulation_protocols_on_human_motor_cortex_excitability_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1388-2457(08)00147-8 DB - PRIME DP - Unbound Medicine ER -