Elias Paolo Casula1, Michele Maiella2, Maria Concetta Pellicciari3, Francesco Porrazzini3, Alessia D'Acunto3, Lorenzo Rocchi4, Giacomo Koch2. 1. Non-Invasive Brain Stimulation Unit/Department of Behavioral and Clinical Neurology, Santa Lucia Foundation, Via Ardeatina 354, 00179 Rome, Italy; Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, Queen Square 33, WC1N 3BG London, United Kingdom. Electronic address: elias.casula@gmail.com. 2. Non-Invasive Brain Stimulation Unit/Department of Behavioral and Clinical Neurology, Santa Lucia Foundation, Via Ardeatina 354, 00179 Rome, Italy; Department of System Medicine, University of Tor Vergata, Via Oxford 81, 00133 Rome, Italy. 3. Non-Invasive Brain Stimulation Unit/Department of Behavioral and Clinical Neurology, Santa Lucia Foundation, Via Ardeatina 354, 00179 Rome, Italy. 4. Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, Queen Square 33, WC1N 3BG London, United Kingdom.
Abstract
OBJECTIVE: To validate two indexes of interhemispheric signal propagation (ISP) and balance (IHB) by combining transcranial magnetic stimulation (TMS) and electroencephalography (EEG). METHODS: We used TMS-EEG to non-invasively stimulate the two hemispheres of 50 healthy volunteers and measured interhemispheric dynamics in terms of ISP and IHB. We repeated our evaluation after three weeks to assess the reliability of our indexes. We also tested whether our TMS-EEG measures were correlated with traditional interhemispheric inhibition (IHI), as measured with motor-evoked potentials (MEPs). RESULTS: Our main results showed that ISP and IHB (1) have a high reproducibility among all the participants tested; (2) have a high test-retest reliability (3) are linearly correlated with IHI, as measured with MEPs. CONCLUSIONS: The main contribution of this study lies in the proposal of new TMS-EEG cortical measures of interhemispheric dynamics and in their validation in terms of intra- and inter-subject reliability. We also provide the first demonstration of the correlation between ISP and IHI. SIGNIFICANCE: Our results are relevant for the investigation of interhemispheric dynamics in clinical populations where MEPs are not reliable.
OBJECTIVE: To validate two indexes of interhemispheric signal propagation (ISP) and balance (IHB) by combining transcranial magnetic stimulation (TMS) and electroencephalography (EEG). METHODS: We used TMS-EEG to non-invasively stimulate the two hemispheres of 50 healthy volunteers and measured interhemispheric dynamics in terms of ISP and IHB. We repeated our evaluation after three weeks to assess the reliability of our indexes. We also tested whether our TMS-EEG measures were correlated with traditional interhemispheric inhibition (IHI), as measured with motor-evoked potentials (MEPs). RESULTS: Our main results showed that ISP and IHB (1) have a high reproducibility among all the participants tested; (2) have a high test-retest reliability (3) are linearly correlated with IHI, as measured with MEPs. CONCLUSIONS: The main contribution of this study lies in the proposal of new TMS-EEG cortical measures of interhemispheric dynamics and in their validation in terms of intra- and inter-subject reliability. We also provide the first demonstration of the correlation between ISP and IHI. SIGNIFICANCE: Our results are relevant for the investigation of interhemispheric dynamics in clinical populations where MEPs are not reliable.
Authors: Elias Paolo Casula; Maria Concetta Pellicciari; Sonia Bonnì; Barbara Spanò; Viviana Ponzo; Ilenia Salsano; Giovanni Giulietti; Alex Martino Cinnera; Michele Maiella; Ilaria Borghi; Lorenzo Rocchi; Marco Bozzali; Fabrizio Sallustio; Carlo Caltagirone; Giacomo Koch Journal: Hum Brain Mapp Date: 2021-01-13 Impact factor: 5.038
Authors: Camarin E Rolle; Fiona M Baumer; Joshua T Jordan; Ketura Berry; Madelleine Garcia; Karen Monusko; Hersh Trivedi; Wei Wu; Russell Toll; Marion S Buckwalter; Maarten Lansberg; Amit Etkin Journal: BMC Neurol Date: 2021-07-16 Impact factor: 2.474