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Monitoring cortical excitability during repetitive transcranial magnetic stimulation in children with ADHD: a single-blind, sham-controlled TMS-EEG study.
PLoS One 2012; 7(11):e50073Plos

Abstract

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) allows non-invasive stimulation of the human brain. However, no suitable marker has yet been established to monitor the immediate rTMS effects on cortical areas in children.

OBJECTIVE

TMS-evoked EEG potentials (TEPs) could present a well-suited marker for real-time monitoring. Monitoring is particularly important in children where only few data about rTMS effects and safety are currently available.

METHODS

In a single-blind sham-controlled study, twenty-five school-aged children with ADHD received subthreshold 1 Hz-rTMS to the primary motor cortex. The TMS-evoked N100 was measured by 64-channel-EEG pre, during and post rTMS, and compared to sham stimulation as an intraindividual control condition.

RESULTS

TMS-evoked N100 amplitude decreased during 1 Hz-rTMS and, at the group level, reached a stable plateau after approximately 500 pulses. N100 amplitude to supra-threshold single pulses post rTMS confirmed the amplitude reduction in comparison to the pre-rTMS level while sham stimulation had no influence. EEG source analysis indicated that the TMS-evoked N100 change reflected rTMS effects in the stimulated motor cortex. Amplitude changes in TMS-evoked N100 and MEPs (pre versus post 1 Hz-rTMS) correlated significantly, but this correlation was also found for pre versus post sham stimulation.

CONCLUSION

The TMS-evoked N100 represents a promising candidate marker to monitor rTMS effects on cortical excitability in children with ADHD. TMS-evoked N100 can be employed to monitor real-time effects of TMS for subthreshold intensities. Though TMS-evoked N100 was a more sensitive parameter for rTMS-specific changes than MEPs in our sample, further studies are necessary to demonstrate whether clinical rTMS effects can be predicted from rTMS-induced changes in TMS-evoked N100 amplitude and to clarify the relationship between rTMS-induced changes in TMS-evoked N100 and MEP amplitudes. The TMS-evoked N100 amplitude reduction after 1 Hz-rTMS could either reflect a globally decreased cortical response to the TMS pulse or a specific decrease in inhibition.

Authors+Show Affiliations

University Hospital for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe University, Frankfurt/Main, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

23185537

Citation

Helfrich, Christian, et al. "Monitoring Cortical Excitability During Repetitive Transcranial Magnetic Stimulation in Children With ADHD: a Single-blind, Sham-controlled TMS-EEG Study." PloS One, vol. 7, no. 11, 2012, pp. e50073.
Helfrich C, Pierau SS, Freitag CM, et al. Monitoring cortical excitability during repetitive transcranial magnetic stimulation in children with ADHD: a single-blind, sham-controlled TMS-EEG study. PLoS ONE. 2012;7(11):e50073.
Helfrich, C., Pierau, S. S., Freitag, C. M., Roeper, J., Ziemann, U., & Bender, S. (2012). Monitoring cortical excitability during repetitive transcranial magnetic stimulation in children with ADHD: a single-blind, sham-controlled TMS-EEG study. PloS One, 7(11), pp. e50073. doi:10.1371/journal.pone.0050073.
Helfrich C, et al. Monitoring Cortical Excitability During Repetitive Transcranial Magnetic Stimulation in Children With ADHD: a Single-blind, Sham-controlled TMS-EEG Study. PLoS ONE. 2012;7(11):e50073. PubMed PMID: 23185537.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Monitoring cortical excitability during repetitive transcranial magnetic stimulation in children with ADHD: a single-blind, sham-controlled TMS-EEG study. AU - Helfrich,Christian, AU - Pierau,Simone S, AU - Freitag,Christine M, AU - Roeper,Jochen, AU - Ziemann,Ulf, AU - Bender,Stephan, Y1 - 2012/11/21/ PY - 2012/08/09/received PY - 2012/10/15/accepted PY - 2012/11/28/entrez PY - 2012/11/28/pubmed PY - 2013/5/15/medline SP - e50073 EP - e50073 JF - PloS one JO - PLoS ONE VL - 7 IS - 11 N2 - BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) allows non-invasive stimulation of the human brain. However, no suitable marker has yet been established to monitor the immediate rTMS effects on cortical areas in children. OBJECTIVE: TMS-evoked EEG potentials (TEPs) could present a well-suited marker for real-time monitoring. Monitoring is particularly important in children where only few data about rTMS effects and safety are currently available. METHODS: In a single-blind sham-controlled study, twenty-five school-aged children with ADHD received subthreshold 1 Hz-rTMS to the primary motor cortex. The TMS-evoked N100 was measured by 64-channel-EEG pre, during and post rTMS, and compared to sham stimulation as an intraindividual control condition. RESULTS: TMS-evoked N100 amplitude decreased during 1 Hz-rTMS and, at the group level, reached a stable plateau after approximately 500 pulses. N100 amplitude to supra-threshold single pulses post rTMS confirmed the amplitude reduction in comparison to the pre-rTMS level while sham stimulation had no influence. EEG source analysis indicated that the TMS-evoked N100 change reflected rTMS effects in the stimulated motor cortex. Amplitude changes in TMS-evoked N100 and MEPs (pre versus post 1 Hz-rTMS) correlated significantly, but this correlation was also found for pre versus post sham stimulation. CONCLUSION: The TMS-evoked N100 represents a promising candidate marker to monitor rTMS effects on cortical excitability in children with ADHD. TMS-evoked N100 can be employed to monitor real-time effects of TMS for subthreshold intensities. Though TMS-evoked N100 was a more sensitive parameter for rTMS-specific changes than MEPs in our sample, further studies are necessary to demonstrate whether clinical rTMS effects can be predicted from rTMS-induced changes in TMS-evoked N100 amplitude and to clarify the relationship between rTMS-induced changes in TMS-evoked N100 and MEP amplitudes. The TMS-evoked N100 amplitude reduction after 1 Hz-rTMS could either reflect a globally decreased cortical response to the TMS pulse or a specific decrease in inhibition. SN - 1932-6203 UR - https://www.unboundmedicine.com/medline/citation/23185537/Monitoring_cortical_excitability_during_repetitive_transcranial_magnetic_stimulation_in_children_with_ADHD:_a_single_blind_sham_controlled_TMS_EEG_study_ L2 - http://dx.plos.org/10.1371/journal.pone.0050073 DB - PRIME DP - Unbound Medicine ER -