Spontaneous and TMS-related EEG changes as new biomarkers to measure anti-epileptic drug effects

Biondi, Andrea; Rocchi, Lorenzo; Santoro, Viviana; Rossini, Pierre; Beatch, Gregory N.; Richardson, Mark P.; Premoli, Isabella

doi:10.1038/s41598-022-05179-x

Cited by 18 publications

(10 citation statements)

References 60 publications

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“…It is possible that, as for M1, different neuronal populations can be activated in the pre–SMA by varying CO and SI; however, investigating this outside M1 is difficult due to the absence of a direct readout such as MEP. This problem can be solved with the use of combined TMS and electroencephalography (TMS–EEG), which allows to record postsynaptic potentials generated by the magnetic pulse in the form of transcranial evoked potentials (TEPs) [ 7 , 18 , 19 , 20 ] or oscillations [ 21 , 22 ], and, thus, to have a readout from cortical areas outside M1.…”

Section: Introductionmentioning

confidence: 99%

“…To assess cortical excitability, we analysed TEPs in terms of discrete peaks and local mean field potential (LMFP), a reference–free measure commonly used to measure local excitability of a specific area, from a cluster of nearby electrodes [ 6 , 23 , 24 ]. To assess cortical oscillations, we computed TMS–related spectral perturbation (TRSP), a measure reflecting the power of TMS–evoked response in the frequency domain [ 21 , 22 , 24 ]. These variables were computed locally to the SMA since we were interested in the response of this area obtained with three different SIs (100%, 120% and 140%) of resting motor threshold (RMT) and four different COs (0°, 90°, 180° and 270°, starting with the coil handle pointing posteriorly on the transverse plane and proceeding counterclockwise).…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Coil Orientation on the Stimulation of the Pre–Supplementary Motor Area: A Combined TMS and EEG Study

et al. 2022

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Studies using transcranial magnetic stimulation (TMS) have demonstrated the importance of direction and intensity of the applied current when the primary motor cortex (M1) is targeted. By varying these, it is possible to stimulate different subsets of neural elements, as demonstrated by modulation of motor evoked potentials (MEPs) and motor behaviour. The latter involves premotor areas as well, and among them, the presupplementary motor area (pre−SMA) has recently received significant attention in the study of motor inhibition. It is possible that, similar to M1, different neuronal populations can be activated by varying the direction and intensity of TMS; however, the absence of a direct electrophysiological outcome has limited this investigation. The problem can be solved by quantifying direct cortical responses by means of combined TMS and electroencephalography (TMS−EEG). We investigated the effect of variable coil orientations (0°, 90°, 180° and 270°) and stimulation intensities (100%, 120% and 140% of resting motor threshold) on local mean field potential (LMFP), transcranial evoked potential (TEP) peaks and TMS−related spectral perturbation (TRSP) from pre−SMA stimulation. As a result, early and late LMFP and peaks were larger, with the coil handle pointing posteriorly (0°) and laterally (90°). This was true also for TRSP in the β−γ range, but, surprisingly, θ−α TRSP was larger with the coil pointing at 180°. A 90° orientation activated the right M1, as shown by MEPs elicitation, thus limiting the spatial specificity of the stimulation. These results suggest that coil orientation and stimulation intensity are critical when stimulating the pre−SMA.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Coil Orientation on the Stimulation of the Pre–Supplementary Motor Area: A Combined TMS and EEG Study

et al. 2022

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“…The study also found that 20 mg of XEN1101 reduced cortical and corticospinal excitability, similar to other AEDs. These findings suggest that TMS can be a valuable tool for informing early-stage clinical trials 9 .…”

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confidence: 86%

XEN1101, a novel potassium channel opener: hope or hype for adults with focal seizure

Fareed,

Sohail,

Siddiqui

et al. 2024

Annals of Medicine &Amp; Surgery

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“…Nonetheless, adequate masking of the auditory evoked potential (AEP) facilitates evaluation of delayed cortical responses to the magnetic field (ter Braack et al, 2015 ), supporting their application as supplementary markers of cortical excitability, both locally and on global scales (Du et al, 2017 ; Roos et al, 2021 ). Investigation of TIO allows the characterisation of rhythmic changes to TMS and can be employed as markers of response to anti‐seizure medications (Biondi et al, 2022 ). Interestingly, early phase synchronisation was found to be linearly dependent on stimulation intensities thus offering an attractive alternative to conventional EMG based cortical excitability markers that may be flawed by spinal excitability (Saari et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

Transcranial magnetic stimulation‐evoked electroencephalography responses as biomarkers for epilepsy: A review of study design and outcomes

Gefferie

Jiménez‐Jiménez

Visser

et al. 2023

Human Brain Mapping

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Transcranial magnetic stimulation (TMS) with electroencephalography (EEG), that is TMS‐EEG, may assist in managing epilepsy. We systematically reviewed the quality of reporting and findings in TMS‐EEG studies on people with epilepsy and healthy controls, and on healthy individuals taking anti‐seizure medication. We searched the Cochrane Library, Embase, PubMed and Web of Science databases for original TMS‐EEG studies comparing people with epilepsy and healthy controls, and healthy subjects before and after taking anti‐seizure medication. Studies should involve quantitative analyses of TMS‐evoked EEG responses. We evaluated the reporting of study population characteristics and TMS‐EEG protocols (TMS sessions and equipment, TMS trials and EEG protocol), assessed the variation between protocols, and recorded the main TMS‐EEG findings. We identified 20 articles reporting 14 unique study populations and TMS methodologies. The median reporting rate for the group of people with epilepsy parameters was 3.5/7 studies and for the TMS parameters was 13/14 studies. TMS protocols varied between studies. Fifteen out of 28 anti‐seizure medication trials in total were evaluated with time‐domain analyses of single‐pulse TMS‐EEG data. Anti‐seizure medication significantly increased N45, and decreased N100 and P180 component amplitudes but in marginal numbers (N45: 8/15, N100: 7/15, P180: 6/15). Eight articles compared people with epilepsy and controls using different analyses, thus limiting comparability. The reporting quality and methodological uniformity between studies evaluating TMS‐EEG as an epilepsy biomarker is poor. The inconsistent findings question the validity of TMS‐EEG as an epilepsy biomarker. To demonstrate TMS‐EEG clinical applicability, methodology and reporting standards are required.

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Spontaneous and TMS-related EEG changes as new biomarkers to measure anti-epileptic drug effects

Cited by 18 publications

References 60 publications

The Effect of Coil Orientation on the Stimulation of the Pre–Supplementary Motor Area: A Combined TMS and EEG Study

The Effect of Coil Orientation on the Stimulation of the Pre–Supplementary Motor Area: A Combined TMS and EEG Study

XEN1101, a novel potassium channel opener: hope or hype for adults with focal seizure

Transcranial magnetic stimulation‐evoked electroencephalography responses as biomarkers for epilepsy: A review of study design and outcomes

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