Reducing motor evoked potential amplitude variability through normalization
BackgroundTranscranial Magnetic Stimulation (TMS) is used for in vivo assessment of human motor cortical excitability, with application of TMS pulses over the motor cortex resulting in muscle responses that can be recorded with electromyography (EMG) as Motor Evoked Potentials (MEPs). These have bee...
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| Format: | Article |
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Frontiers Media S.A.
2024-01-01
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| Series: | Frontiers in Psychiatry |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fpsyt.2024.1279072/full |
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| author | Francisco Faro Viana Francisco Faro Viana Gonçalo Cotovio Gonçalo Cotovio Gonçalo Cotovio Gonçalo Cotovio Daniel Rodrigues da Silva Daniel Rodrigues da Silva Carolina Seybert Carolina Seybert Patrícia Pereira Patrícia Pereira Patrícia Pereira Artur Silva Filipe Carvalho Albino J. Oliveira-Maia Albino J. Oliveira-Maia Albino J. Oliveira-Maia |
| author_facet | Francisco Faro Viana Francisco Faro Viana Gonçalo Cotovio Gonçalo Cotovio Gonçalo Cotovio Gonçalo Cotovio Daniel Rodrigues da Silva Daniel Rodrigues da Silva Carolina Seybert Carolina Seybert Patrícia Pereira Patrícia Pereira Patrícia Pereira Artur Silva Filipe Carvalho Albino J. Oliveira-Maia Albino J. Oliveira-Maia Albino J. Oliveira-Maia |
| author_sort | Francisco Faro Viana |
| collection | DOAJ |
| description | BackgroundTranscranial Magnetic Stimulation (TMS) is used for in vivo assessment of human motor cortical excitability, with application of TMS pulses over the motor cortex resulting in muscle responses that can be recorded with electromyography (EMG) as Motor Evoked Potentials (MEPs). These have been widely explored as potential biomarkers for neuropsychiatric disorders but methodological heterogeneity in acquisition, and inherent high variability, have led to constraints in reproducibility. Normalization, consisting in scaling the signal of interest to a known and repeatable measurement, reduces variability and is standard practice for between-subject comparisons of EMG. The effect of normalization on variability of MEP amplitude has not yet been explored and was assessed here using several methods.MethodsThree maximal voluntary isometric contractions (MVICs) and 40 MEPs were collected from the right hand in healthy volunteers, with a retest session conducted 4 to 8 weeks later. MEP amplitude was normalized using either external references (MVICs) or internal references (extreme MEPs). Iterative re-sampling of 30 normalized MEPs per subject was repeated 5,000 times to define, for each normalization method, distributions for between-subject coefficients of variation (CV) of the mean MEP amplitude. Intra-class correlation coefficients (ICC) were used to assess the impact of normalization on test–retest stability of MEP amplitude measurements.ResultsIn the absence of normalization, MEPs collected from the right hand of 47 healthy volunteers were within reported values regarding between-subject variability (95% confidence intervals for the CV: [1.0567,1.0577]) and showed good temporal stability (ICC = 0.77). Internal reference normalization substantially reduced between-subject variability, by values of up to 64%, while external reference normalization had no impact or increased between-subject variability. Normalization with the smallest references reduced test–retest stability, with use of the largest references resulting in slight reduction or improvement of ICCs. Internal reference normalization using the largest MEPs was found to be robust to several sensitivity analyses.ConclusionInternal, but not external, reference normalization reduces between-subject variability of MEP amplitude, and has a minimal impact on within-subject variability when conducted with the largest references. Additional research is necessary to further validate these normalization methods toward potential use of MEPs as biomarkers of neuropsychiatric disorders. |
| first_indexed | 2024-03-08T09:31:31Z |
| format | Article |
| id | doaj.art-f4fa56ec72374a2aaa5e7d2d66d9e77b |
| institution | Directory Open Access Journal |
| issn | 1664-0640 |
| language | English |
| last_indexed | 2024-03-08T09:31:31Z |
| publishDate | 2024-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Psychiatry |
| spelling | doaj.art-f4fa56ec72374a2aaa5e7d2d66d9e77b2024-01-31T04:23:15ZengFrontiers Media S.A.Frontiers in Psychiatry1664-06402024-01-011510.3389/fpsyt.2024.12790721279072Reducing motor evoked potential amplitude variability through normalizationFrancisco Faro Viana0Francisco Faro Viana1Gonçalo Cotovio2Gonçalo Cotovio3Gonçalo Cotovio4Gonçalo Cotovio5Daniel Rodrigues da Silva6Daniel Rodrigues da Silva7Carolina Seybert8Carolina Seybert9Patrícia Pereira10Patrícia Pereira11Patrícia Pereira12Artur Silva13Filipe Carvalho14Albino J. Oliveira-Maia15Albino J. Oliveira-Maia16Albino J. Oliveira-Maia17Champalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Clinical Centre, Champalimaud Foundation, Lisbon, PortugalChampalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Clinical Centre, Champalimaud Foundation, Lisbon, PortugalNOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, PortugalDepartment of Psychiatry and Mental Health, Centro Hospitalar de Lisboa Ocidental, Lisbon, PortugalChampalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Clinical Centre, Champalimaud Foundation, Lisbon, PortugalChampalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Clinical Centre, Champalimaud Foundation, Lisbon, PortugalChampalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Clinical Centre, Champalimaud Foundation, Lisbon, PortugalPortuguese Red Cross Health School, Lisbon, PortugalChampalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Research, Champalimaud Foundation, Lisbon, PortugalChampalimaud Clinical Centre, Champalimaud Foundation, Lisbon, PortugalNOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, PortugalBackgroundTranscranial Magnetic Stimulation (TMS) is used for in vivo assessment of human motor cortical excitability, with application of TMS pulses over the motor cortex resulting in muscle responses that can be recorded with electromyography (EMG) as Motor Evoked Potentials (MEPs). These have been widely explored as potential biomarkers for neuropsychiatric disorders but methodological heterogeneity in acquisition, and inherent high variability, have led to constraints in reproducibility. Normalization, consisting in scaling the signal of interest to a known and repeatable measurement, reduces variability and is standard practice for between-subject comparisons of EMG. The effect of normalization on variability of MEP amplitude has not yet been explored and was assessed here using several methods.MethodsThree maximal voluntary isometric contractions (MVICs) and 40 MEPs were collected from the right hand in healthy volunteers, with a retest session conducted 4 to 8 weeks later. MEP amplitude was normalized using either external references (MVICs) or internal references (extreme MEPs). Iterative re-sampling of 30 normalized MEPs per subject was repeated 5,000 times to define, for each normalization method, distributions for between-subject coefficients of variation (CV) of the mean MEP amplitude. Intra-class correlation coefficients (ICC) were used to assess the impact of normalization on test–retest stability of MEP amplitude measurements.ResultsIn the absence of normalization, MEPs collected from the right hand of 47 healthy volunteers were within reported values regarding between-subject variability (95% confidence intervals for the CV: [1.0567,1.0577]) and showed good temporal stability (ICC = 0.77). Internal reference normalization substantially reduced between-subject variability, by values of up to 64%, while external reference normalization had no impact or increased between-subject variability. Normalization with the smallest references reduced test–retest stability, with use of the largest references resulting in slight reduction or improvement of ICCs. Internal reference normalization using the largest MEPs was found to be robust to several sensitivity analyses.ConclusionInternal, but not external, reference normalization reduces between-subject variability of MEP amplitude, and has a minimal impact on within-subject variability when conducted with the largest references. Additional research is necessary to further validate these normalization methods toward potential use of MEPs as biomarkers of neuropsychiatric disorders.https://www.frontiersin.org/articles/10.3389/fpsyt.2024.1279072/fulltranscranial magnetic stimulationcortical excitabilitymotor evoked potentialnormalizationvariability |
| spellingShingle | Francisco Faro Viana Francisco Faro Viana Gonçalo Cotovio Gonçalo Cotovio Gonçalo Cotovio Gonçalo Cotovio Daniel Rodrigues da Silva Daniel Rodrigues da Silva Carolina Seybert Carolina Seybert Patrícia Pereira Patrícia Pereira Patrícia Pereira Artur Silva Filipe Carvalho Albino J. Oliveira-Maia Albino J. Oliveira-Maia Albino J. Oliveira-Maia Reducing motor evoked potential amplitude variability through normalization Frontiers in Psychiatry transcranial magnetic stimulation cortical excitability motor evoked potential normalization variability |
| title | Reducing motor evoked potential amplitude variability through normalization |
| title_full | Reducing motor evoked potential amplitude variability through normalization |
| title_fullStr | Reducing motor evoked potential amplitude variability through normalization |
| title_full_unstemmed | Reducing motor evoked potential amplitude variability through normalization |
| title_short | Reducing motor evoked potential amplitude variability through normalization |
| title_sort | reducing motor evoked potential amplitude variability through normalization |
| topic | transcranial magnetic stimulation cortical excitability motor evoked potential normalization variability |
| url | https://www.frontiersin.org/articles/10.3389/fpsyt.2024.1279072/full |
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