title: The variability of motor evoked potential latencies in neurosurgical motor mapping by preoperative navigated transcranial magnetic stimulation.
abstract: Recording of motor evoked potentials (MEPs) is used during navigated transcranial magnetic stimulation (nTMS) motor mapping to locate motor function in the human brain. However, factors potentially underlying MEP latency variability in neurosurgical motor mapping are vastly unknown. In the context of this study, one hundred brain tumor patients underwent preoperative nTMS-based motor mapping of the tumor hemisphere between 2010 and 2013. Fourteen predefined predictor variables were recorded, and MEP latencies of abductor pollicis brevis muscle (APB), abductor digiti minimi muscle (ADM), and flexor carpi radialis muscle (FCR) were analyzed using linear mixed-effect multiple regression analysis with the forward step-wise model comparison approach.
  
  
  
  Common factors (relevant to APB, ADM, and FCR) for MEP latency variability were gender, most likely due to body height, and antiepileptic drug (AED) intake. Muscle-specific factors (relevant to APB, ADM, or FCR) for MEP latency variability were resting motor threshold (rMT), tumor side, and tumor location.
  
  
  
  Based on a large cohort of neurosurgical patients, this study provides data on a wide range of clinical factors that may underlie MEP latency variability. The factors that significantly contributed to MEP latency variability should be standardly recorded and taken into consideration during neurosurgical motor mapping.
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Sollmann
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Lucia
authors.initials: L
authors.lastname: Bulubas
authors.affiliation: Faculty of Linguistics, Philology, and Phonetics, University of Oxford, Walton Street, Oxford, OX1 2HG, UK.
authors.forename: Noriko
authors.initials: N
authors.lastname: Tanigawa
authors.affiliation: TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.|Section of Neuroradiology, Department of Radiology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Zimmer
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Sandro.Krieg@tum.de.|TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. Sandro.Krieg@tum.de.
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Krieg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000601:surgery; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000502:physiology*; D038361:Neuronavigation / Q000379:methods*; D057234:Preoperative Period; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
keywords: Brain tumor; Cortical mapping; Electromyography; Motor evoked potentials; Navigated transcranial magnetic stimulation; Presurgical motor mapping