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Stimulus waveform influences the efficacy of repetitive transcranial magnetic stimulation.
J Affect Disord. 2007 Jan; 97(1-3):271-6.JA

Abstract

BACKGROUND

Optimising stimulus parameters is important in maximising the efficacy of repetitive transcranial magnetic stimulation (rTMS) in treatment applications. RTMS over motor cortex has been reported as more effective in producing corticospinal inhibition when a monophasic rather than a biphasic stimulus waveform is used. However, non-optimal coil orientation and high intensities of monophasic rTMS may have influenced previous results.

METHODS

In eight healthy subjects, we measured motor evoked potentials (MEPs) in a hand muscle after monophasic and biphasic rTMS (1 Hz for 15 min) over the motor cortex with the coil always in the optimal orientation. MEPs were evoked by both monophasic and biphasic stimuli.

RESULTS

MEPs were initially significantly reduced after monophasic but not biphasic rTMS. However, a late reduction was seen after biphasic rTMS.

LIMITATIONS

These motor cortical findings may not be directly applicable to prefrontal rTMS.

CONCLUSIONS

This study confirms that low frequency rTMS with monophasic pulses produces more corticospinal inhibition than with biphasic pulses, even when the direction of current and intensity are as well-matched as possible.

Authors+Show Affiliations

Prince of Wales Medical Research Institute, Randwick, NSW, Australia.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16887197

Citation

Taylor, Janet L., and Colleen K. Loo. "Stimulus Waveform Influences the Efficacy of Repetitive Transcranial Magnetic Stimulation." Journal of Affective Disorders, vol. 97, no. 1-3, 2007, pp. 271-6.
Taylor JL, Loo CK. Stimulus waveform influences the efficacy of repetitive transcranial magnetic stimulation. J Affect Disord. 2007;97(1-3):271-6.
Taylor, J. L., & Loo, C. K. (2007). Stimulus waveform influences the efficacy of repetitive transcranial magnetic stimulation. Journal of Affective Disorders, 97(1-3), 271-6.
Taylor JL, Loo CK. Stimulus Waveform Influences the Efficacy of Repetitive Transcranial Magnetic Stimulation. J Affect Disord. 2007;97(1-3):271-6. PubMed PMID: 16887197.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Stimulus waveform influences the efficacy of repetitive transcranial magnetic stimulation. AU - Taylor,Janet L, AU - Loo,Colleen K, Y1 - 2006/08/02/ PY - 2006/05/30/received PY - 2006/06/30/revised PY - 2006/06/30/accepted PY - 2006/8/5/pubmed PY - 2007/3/21/medline PY - 2006/8/5/entrez SP - 271 EP - 6 JF - Journal of affective disorders JO - J Affect Disord VL - 97 IS - 1-3 N2 - BACKGROUND: Optimising stimulus parameters is important in maximising the efficacy of repetitive transcranial magnetic stimulation (rTMS) in treatment applications. RTMS over motor cortex has been reported as more effective in producing corticospinal inhibition when a monophasic rather than a biphasic stimulus waveform is used. However, non-optimal coil orientation and high intensities of monophasic rTMS may have influenced previous results. METHODS: In eight healthy subjects, we measured motor evoked potentials (MEPs) in a hand muscle after monophasic and biphasic rTMS (1 Hz for 15 min) over the motor cortex with the coil always in the optimal orientation. MEPs were evoked by both monophasic and biphasic stimuli. RESULTS: MEPs were initially significantly reduced after monophasic but not biphasic rTMS. However, a late reduction was seen after biphasic rTMS. LIMITATIONS: These motor cortical findings may not be directly applicable to prefrontal rTMS. CONCLUSIONS: This study confirms that low frequency rTMS with monophasic pulses produces more corticospinal inhibition than with biphasic pulses, even when the direction of current and intensity are as well-matched as possible. SN - 0165-0327 UR - https://www.unboundmedicine.com/medline/citation/16887197/Stimulus_waveform_influences_the_efficacy_of_repetitive_transcranial_magnetic_stimulation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0165-0327(06)00294-1 DB - PRIME DP - Unbound Medicine ER -