1. Resting and active motor thresholds versus stimulus–response curves to determine transcranial magnetic stimulation intensity in quadriceps femoris
- Author
-
John Temesi, Samuel Verges, Thomas Rupp, Mathieu Gruet, Guillaume Y. Millet, Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM ), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM), Laboratoire HP2, Université Joseph Fourier - Grenoble 1 (UJF)-CHU Grenoble, Laboratoire Motricité Humaine Expertise Sport Santé (LAMHESS), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université de Toulon (UTLN)-Université Côte d'Azur (UCA), Hypoxie et physiopathologies cardiovasculaire et respiratoire, Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratory of Human Performance, University of Calgary, Rhône-Alpes Region, Fonds de Dotation Recherche en Santé Respiratoire, appel d'offres 2011, Laboratoire Interuniversitaire de Biologie de la Motricité ( LIBM ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] ( UJM ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ), Université Joseph Fourier - Grenoble 1 ( UJF ) -CHU Grenoble, Laboratoire Motricité Humaine Expertise Sport Santé ( LAMHESS ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Université de Toulon ( UTLN ), Institut National de la Santé et de la Recherche Médicale ( INSERM ), BMC, Ed., Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Hypoxie : Physiopathologie Respiratoire et Cardiovasculaire (HP2), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Santé et de la Recherche Médicale (INSERM)
- Subjects
Adult ,Male ,medicine.medical_specialty ,genetic structures ,[SDV.MHEP.PHY] Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] ,Vastus medialis ,[SDV.NEU.NB]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Neurobiology ,medicine.medical_treatment ,Health Informatics ,Stimulation ,Electromyography ,Stimulus (physiology) ,Stimulus intensity determination ,Quadriceps Muscle ,03 medical and health sciences ,0302 clinical medicine ,Physical medicine and rehabilitation ,[SDV.MHEP.PHY]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] ,medicine ,Humans ,Methodological considerations ,Fatigue ,medicine.diagnostic_test ,[ SDV.MHEP.PHY ] Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] ,Research ,Rehabilitation ,[SDV.NEU.NB] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Neurobiology ,Motor Cortex ,030229 sport sciences ,Evoked Potentials, Motor ,C600 ,Transcranial Magnetic Stimulation ,Coactivation ,body regions ,Transcranial magnetic stimulation ,medicine.anatomical_structure ,[ SDV.NEU.NB ] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Neurobiology ,Physical therapy ,medicine.symptom ,Psychology ,human activities ,030217 neurology & neurosurgery ,Muscle Contraction ,Muscle contraction ,Motor cortex - Abstract
International audience; BACKGROUND: Transcranial magnetic stimulation (TMS) is a widely-used investigative technique in motor cortical evaluation. Recently, there has been a surge in TMS studies evaluating lower-limb fatigue. TMS intensity of 120-130% resting motor threshold (RMT) and 120% active motor threshold (AMT) and TMS intensity determined using stimulus-response curves during muscular contraction have been used in these studies. With the expansion of fatigue research in locomotion, the quadriceps femoris is increasingly of interest. It is important to select a stimulus intensity appropriate to evaluate the variables, including voluntary activation, being measured in this functionally important muscle group. This study assessed whether selected quadriceps TMS stimulus intensity determined by frequently employed methods is similar between methods and muscles. METHODS: Stimulus intensity in vastus lateralis, rectus femoris and vastus medialis muscles was determined by RMT, AMT (i.e. during brief voluntary contractions at 10% maximal voluntary force, MVC) and maximal motor-evoked potential (MEP) amplitude from stimulus-response curves during brief voluntary contractions at 10, 20 and 50% MVC at different stimulus intensities. RESULTS: Stimulus intensity determined from a 10% MVC stimulus-response curve and at 120 and 130% RMT was higher than stimulus intensity at 120% AMT (lowest) and from a 50% MVC stimulus-response curve (p < 0.05). Stimulus intensity from a 20% MVC stimulus-response curve was similar to 120% RMT and 50% MVC stimulus-response curve. Mean stimulus intensity for stimulus-response curves at 10, 20 and 50% MVC corresponded to approximately 135, 115 and 100% RMT and 180, 155 and 130% AMT, respectively. Selected stimulus intensity was similar between muscles for all methods (p > 0.05). CONCLUSIONS: Similar optimal stimulus intensity and maximal MEP amplitudes at 20 and 50% MVC and the minimal risk of residual fatigue at 20% MVC suggest that a 20% MVC stimulus-response curve is appropriate for determining TMS stimulus intensity in the quadriceps femoris. The higher selected stimulus intensities at 120-130% RMT have the potential to cause increased coactivation and discomfort and the lower stimulus intensity at 120% AMT may underestimate evoked responses. One muscle may also act as a surrogate in determining optimal quadriceps femoris stimulation intensity.
- Published
- 2014