Skip to main content
SpringerLink
Log in

Motor Evoked Potentials

  • Chapter
  • First Online:
Principles of Neurophysiological Assessment, Mapping, and Monitoring

  • 1038 Accesses

Abstract

Iatrogenic injuries are an undesired consequence of surgery, yet iatrogenic injuries to the motor system are much more devastating to a patient’s quality of life than most injuries to the sensory system. Generally, an injury to the spinal cord will be most likely be picked up by somatosensory evoked potentials (SSEPs), yet a focal injury to the anterior spinal artery (ASA) may be missed. There is a lot of evidence in the literature describing selective injury to the anterolateral columns sparing dorsal columns with preserved SSEPs. The inclusions of motor evoked potentials (MEPs) to the intraoperative monitoring toolbox can help to confirm/prevent selective lesions to the anterolateral columns of the spinal cord. Yet, MEPs are not without their limitations. Even with these limitations, proper application and interpretation of MEP data can be a significant adjunct in reducing iatrogenic injury during surgery.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 119.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 159.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Notes

  1. 1.

    At the time of this writing.

  2. 2.

    Stimulation directly on the brain surface or dura uses other specially designed or modified electrodes and significantly lowers stimulus levels; otherwise the parameters and montage for stimulation are very similar. The technique of direct subcortical white matter stimulation is somewhat different in that the cathode is the stimulating (active) electrode which is different than for eliciting MEPs from the cerebral cortex.

  3. 3.

    One may also use stimulation to map the cortex. This is not the subject matter for this chapter, although the techniques are similar.

References

  1. Larson SJ, Sances A, Christenson PC. Evoked somatosensory potentials in man. Arch Neurol. 1966;15:88.

    Article  CAS  PubMed  Google Scholar 

  2. Minahan RE, Sepukuty JP, Lesses RP, Sponseller PD, Kostuik JP. Anterior spinal cord injury with preserved neurogenic ‘motor’ evoked potentials. Clin Neurophysiol. 2001;112(8):1442–50.

    Article  CAS  PubMed  Google Scholar 

  3. Jones SJ, Buonamassa S, Crockard HA. Two cases of quadriparesis following anterior cervical discectomy, with normal perioperative somatosensory evoked potentials. J Neurol Neurosurg Psychiatry. 2003;74:273–6.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  4. Pelosi L, Lamb J, Grevitt M, Mehdian SM, Webb JK, Blumhardt LD. Combined monitoring of motor and somatosensory evoked potentials in orthopaedic spinal surgery. Clin Neurophysiol. 2002;113:1082–91.

    Article  PubMed  Google Scholar 

  5. Hilibrand AS, Schwartz DM, Sethuraman V, Vaccaro AR, Albert TJ. Comparison of transcranial electrical motor and somatosensory evoked potential monitoring during cervical spine surgery. J Bone Joint Surg. 2004;86-a(6):1248–53.

    Article  Google Scholar 

  6. Schwartz DM, Auerbach JD, Dormans JP, Flynn J, Bowe A, Laufer S, et al. Neurophysiological detection of impending spinal cord injury during scoliosis surgery. J Bone Joint Surg. 2007;89:2440–9.

    PubMed  Google Scholar 

  7. Cobb M. Timeline: exorcizing the animal spirits: Jan Swammerdam on nerve function. Nat Rev Neurosci. 2002;3:395–400. Swammerdam J. The book of nature II. London: Seyffert; 1758. p. 122–32.

    Article  CAS  PubMed  Google Scholar 

  8. Bresadola M. Medicine and science in the life of Luigi Galvani. Brain Res Bull. 1998;46(5):367–80.

    Article  CAS  PubMed  Google Scholar 

  9. Walker AE. The development of the concept of cerebral localization in the nineteenth century. Bull Hist Med. 1957;31:99–121.

    CAS  PubMed  Google Scholar 

  10. Fritsch G, Hitzig E. On the electrical excitability of the cerebrum (1870), trans. von Bonin G. In: Some papers on the cerebral cortex. Springfield, IL: Charles C Thomas; 1960. p. 73–96.

    Google Scholar 

  11. Penfield WG, Boldrey E. Somatic motor and sensory representation in the cerebral cortex of man as studies by electrical stimulation. Brain. 1937;60:389–443.

    Article  Google Scholar 

  12. Patton HD, Amassian VE. Responses in the corticospinal tract of cat and monkey. Fed Proc. 1952;11:119.

    Google Scholar 

  13. Amassian VE. Animal and human motor system neurophysiology related to intraoperative monitoring. In: Deletis V, Shils JL, editors. Neurophysiology: a modern approach. New York: Academic; 2002.

    Google Scholar 

  14. Merton PA, Morton HB. Stimulation of the cerebral cortex in the intact human subject. Nature. 1980;285(5762):227.

    Article  CAS  PubMed  Google Scholar 

  15. Levy WJ, York DH, McCaffrey M, Tanzer F. Motor evoked potentials from transcranial electrical stimulation of the motor cortex in humans. Neurosurgery. 1984;15:287–302.

    Article  CAS  PubMed  Google Scholar 

  16. Katayama Y, Tsubokawa T, Maejima S, Hirayama T, Yamamoto T. Corticospinal direct response in humans: identification of the motor cortex during intracranial surgery under general anesthesia. J Neurol Neurosurg Psychiatry. 1988;51(1):50–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  17. Burke D, Hicks RG, Stephen JP. Corticospinal volleys evoked by anodal and cathodal stimulation of the human motor cortex. J Physiol. 1990;425:283–99.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Deletis V, Rodi Z, Amassian VE. Neurophysiological mechanisms underlying motor evoked potentials in anesthetized humans. Part 2. Relationship between epidurally and muscle recorded MEPs in man. Clin Neurophysiol. 2001;112(3):445–52.

    Article  CAS  PubMed  Google Scholar 

  19. Deletis V, Isgum V, Amassian VE. Neurophysiological mechanisms underlying motor evoked potentials in anesthetized humans. Part 2. Recovery time of corticospinal tract direct waves elicited by pairs of transcranial electrical stimuli. Clin Neurophysiol. 2001;112:438–44.

    Article  CAS  PubMed  Google Scholar 

  20. Brodmann K. Vergleichende Lokalisationslehre der Grosshirnrinde. Leipzig: Johann Ambrosius Bart; 1909.

    Google Scholar 

  21. Martin GF, Fisher AM. A further evaluation of the origin, the course and the termination of the opossum corticospinal tract. J Neurol Sci. 1968;7(1):177–87.

    Article  CAS  PubMed  Google Scholar 

  22. Rothwell J. Control of human movement. London: Chapman and Hall; 1986.

    Google Scholar 

  23. He S, Dum R, Strick P. Topographic organization of corticospinal projections from the frontal lobe: motor areas on the lateral surface of the hemisphere. J Neurosci. 1993;13(3):952–80.

    Article  CAS  PubMed  Google Scholar 

  24. Marx JJ, Iannetti GD, Thömke F, Fitzek S, Urban PP, Stoeter P, et al. Somatotopic organization of the corticospinal tract in the human brainstem: a MRI-based mapping analysis. Ann Neurol. 2005;57(6):824–31.

    Article  PubMed  Google Scholar 

  25. Nathan PW, Smith MC, Deacon P. The corticospinal tracts in man. Course and location of fibers at different segmental levels. Brain. 1990;113(Pt 2):303–24.

    Article  PubMed  Google Scholar 

  26. Davidoff RA. Handbook of the spinal cord: anatomy and physiology, vol. 2 and 3. New York: Marcel Dekker; 1984.

    Google Scholar 

  27. Arle JE, Iftimia N, Shils JL, Mei L, Carlson KW. Dynamic computational model of the human spinal cord connectome. Neural Comput. 2019;31:388–416.

    Article  PubMed  Google Scholar 

  28. Ralston DD, Ralston HJ. The terminations of corticospinal tract axons in the macaque monkey. J Comp Neurol. 1985;242(3):325–37.

    Article  CAS  PubMed  Google Scholar 

  29. Shamji MF, Maziak DE, Shamji FM, Ginsberg RJ, Pon R. Circulation of the spinal cord: an important consideration for thoracic surgeons. Ann Thorac Surg. 2003;76:315–21.

    Article  PubMed  Google Scholar 

  30. Domisse GF. The blood supply of the spinal cord: a critical vascular zone in spinal surgery. J Bone Joint Surg. 1974;56B:225–35.

    Article  Google Scholar 

  31. Deletis V. Intraoperative neurophysiology and methodologies used to monitor the functional integrity of the motor system. In: Deletis V, Shils JL, editors. Neurophysiology in neurosurgery. San Diego: Academic; 2002. p. 25–51.

    Chapter  Google Scholar 

  32. Berlin L, Amassian VE. Pyramidal tract responses during seizures. Electroencephalogr Clin Neurophysiol. 1965;19:587–97.

    Article  CAS  PubMed  Google Scholar 

  33. Rattay F. Analysis of models for external stimulation of axons. IEEE Trans Biomed Eng. 1986;33(10):974–7.

    Article  CAS  PubMed  Google Scholar 

  34. Haghighi SS, Green KD, Oro JJ, Drake RK, Kracke GR. Depressive effect of isoflurane anesthesia on motor evoked potentials. Neurosurgery. 1990;26(6):993–7.

    Article  CAS  PubMed  Google Scholar 

  35. Zentner J, Albrecht T, Heuser D. Influence of halothane, enflurane, and isoflurane on motor evoked potentials. Neurosurgery. 1992;31(2):298–305.

    Article  CAS  PubMed  Google Scholar 

  36. Sloan TB, Rogers JN. Inhalational anesthesia alters the optimal ISI for multipulse transcranial motor evoked potentials in the baboon. J Neurosurg Anesthesiol. 1996;8:346.

    Google Scholar 

  37. Sloan T. Anesthetic effects on electrophysiologic recordings. J Clin Neurophysiol. 1998;15(3):217.

    Article  CAS  PubMed  Google Scholar 

  38. Scheufler KM, Reinacher PC, Blumrich W, Zentner J, Priebe H-J. The modifying effects of stimulation pattern and propofol plasma concentration on motor-evoked potentials. Anesth Analg. 2005;100(2):440–7.

    Article  CAS  PubMed  Google Scholar 

  39. Kothbauer K, Deletis V, Epstein F. Motor-evoked potential monitoring for intramedullary spinal cord tumor surgery: correlation of clinical and neurophysiological data in a series of 100 consecutive cases. Neurosurg Focus. 1998;4(5):1–9.

    Article  Google Scholar 

  40. Abalkail TM, MacDonald DB, AlThubaiti I, AlOtaibi FA, Stigsby B, Mokeen AA, et al. Intraoperative direct cortical stimulation motor evoked potentials: stimulus parameter recommendations based on rheobase and chronaxie. Clin Neurophysiol. 2017;128:2300–8.

    Article  Google Scholar 

  41. Taniguchi M, Cedzich C, Schramm J. Modification of cortical stimulation for motor evoked potentials under general anesthesia: technical description. Neurosurgery. 1993;32(2):219–26.

    Article  CAS  PubMed  Google Scholar 

  42. Szelenyi A, Kothbauer KF, Deletis V. Transcranial electric stimulation for intraoperative motor evoked potential monitoring: stimulation parameters and electrode montages. Clin Neurophysiol. 2007;118(7):1586–95.

    Article  PubMed  Google Scholar 

  43. Journée HL, Polak HE, De Kleuver M, Langeloo DD, Postma AA. Improved neuromonitoring during spinal surgery using double-train transcranial electrical stimulation. Med Biol Eng Comput. 2004;42(1):110–3.

    Article  PubMed  Google Scholar 

  44. Rothwell JC. Techniques and mechanisms of action of transcranial stimulation of the human motor cortex. J Neurosci Methods. 1997;74:113–22.

    Article  CAS  Google Scholar 

  45. Rattay F. Analysis of models for external stimulation of axons. IEEE Trans Biomed Eng. 1986;BME-33:974–7.

    Article  Google Scholar 

  46. Rank JB. Which elements are excited in electrical stimulation of mammalian central nervous system: a review. Brain Res. 1975;98:417–40.

    Article  Google Scholar 

  47. Di Lazzaro V, Oliviero A, Profice P, Saturno E, Pilato F, Insola A, et al. Comparison of descending volleys evoked by transcranial magnetic and electric stimulation in conscious humans. Electroencephalogr Clin Neurophysiol. 1998;109:397–401.

    Article  PubMed  Google Scholar 

  48. Hallett M. Transcranial magnetic stimulation: a primer. Neuron. 2007;55:187–99.

    Article  CAS  PubMed  Google Scholar 

  49. Aglio LS, Romero R, Desai S, Ramirez M, Gonzalez AA, Gugino LD. The use of transcranial magnetic stimulation for monitoring descending spinal cord motor function. Clin Electroencephalogr. 2002;33(1):30–41.

    Article  PubMed  Google Scholar 

  50. Macdonald DB, Skinner S, Shils J, Yingling C. Intraoperative motor evoked potential monitoring - A position statement by the American Society of Neurophysiological Monitoring. Clin Neurophysiol. 2013;124:2291–316.

    Article  CAS  PubMed  Google Scholar 

  51. Deletis V, Fernandez-Conejero I, Ulkatan S, Costantino P. Methodology for intraoperatively eliciting motor evoked potentials in the vocal muscles by electrical stimulation of the corticobulbar tracts. Clin Neurophysiol. 2009;120:336–41.

    Article  PubMed  Google Scholar 

  52. Deletis V, Fernandez-Conejero I, Ulkatan S, Rogic M, Carbo EL, Hiltzik D. Methodology for intra-operative recording of the corticobulbar motor evoked potentials for cricothyroid muscles. Clin Neurophysiol. 2011;122:1883–9.

    Article  PubMed  Google Scholar 

  53. Dong C, MacDonald DB, Akagami R, Westerberg B, AlKhani A, AlShail E, et al. Intraoperative facial motor evoked potential monitoring with transcranial electrical stimulation during skull base surgery. Clin Neurophysiol. 2005;116:588–96.

    Article  PubMed  Google Scholar 

  54. Quiñones-Hinojosa A, Lyon R, Zada G, Lamborn KR, Gupta N, Parsa AT, et al. Changes in transcranial motor evoked potentials during intramedullary spinal cord tumor resection correlate with postoperative motor function. Neurosurgery. 2005;56(5):982–93.

    PubMed  Google Scholar 

  55. Calancie B, Harris W, Broton JG, Alexeeva N, Green BA. “Threshold-level” multipulse transcranial electrical stimulation of motor cortex for intraoperative monitoring of spinal motor tracts: description of method and comparison to somatosensory evoked potential monitoring. J Neurosurg. 1998;88(3):457–70.

    Article  CAS  PubMed  Google Scholar 

  56. Calancie B, Harris W, Brindle GF, Green BA, Landy HJ. Threshold-level repetitive transcranial electrical stimulation for intraoperative monitoring of central motor conduction. J Neurosurg. 2001;95(2 Suppl):161–8.

    CAS  PubMed  Google Scholar 

  57. MacDonald DB. Intraoperative motor evoked potential monitoring: overview and update. J Clin Monit Comput. 2006;20(5):347–77.

    Article  PubMed  Google Scholar 

  58. Szelényi A, Kothbauer K, de Camargo AB, Langer D, Flamm ES, Deletis V. Motor evoked potential monitoring during cerebral aneurysm surgery: technical aspects and comparison of transcranial and direct cortical stimulation. Neurosurgery. 2005;57(4 Suppl):331–8.

    PubMed  Google Scholar 

  59. Ebeling A, Schmid UD, Ying H, Reulen HJ. Safe surgery of lesions near the motor cortex using intra-operative mapping techniques: a report in 50 patients. Acta Neurochir. 1992;119:23–8.

    Article  CAS  PubMed  Google Scholar 

  60. Kombos T, Suss O, Kern BC, Funk T, Hoell T, Kopetsch O, et al. Comparison between monopolar and bipolar electrical stimulation of the motor cortex. Acta Neurochir. 1999;141:1295–301.

    Article  CAS  PubMed  Google Scholar 

  61. Szelenyi A, Langer D, Beck J, Raabe A, Flamm EX, Seifert V, et al. Transcranial and direct cortical stimulation for motor evoked potential monitoring in intracerebral aneurysm surgery. Neurophysiol Clin. 2007;37:391–8.

    Article  CAS  PubMed  Google Scholar 

  62. Seidel K, Beck J, Stieflitz L, Schucht P, Raabe A. The warning-sign hierarchy between quantitative subcortical motor mapping and continuous motor evoked potential monitoring during resection of supratentorial brain tumors. J Neurosurg. 2013;118:287–96.

    Article  PubMed  Google Scholar 

  63. Kamada K, Todo T, Ota T, Ino K, Masitani Y, Aoki S, et al. The motor-evoked potential threshold evaluated by tractography and electrical stimulation. J Neurosurg. 2009;111:785–95.

    Article  PubMed  Google Scholar 

  64. Nossek E, Korn A, Shahar T, Kanner AA, Yaffe H, Marcovici D, et al. Intraoperative mapping and monitoring of the corticospinal tracts with neurophysiological assessment and 3-dimensional ultrasonography-based navigation. Clinical article. J Neurosurg. 2011;114:738–46.

    Article  PubMed  Google Scholar 

  65. Journee HL, Polak HE, de Kleuver M. Influence of electrode impedance on threshold voltage for transcranial electrical stimulation in motor evoked potential monitoring. Med Biol Eng Comput. 2004;42(4):557–61.

    Article  CAS  PubMed  Google Scholar 

  66. Ruley MR, Doan AT, Vogel RW, Aguirre AO, Pieri KS, Scheid EH. Use of motor evoked potentials during lateral lumbar interbody fusion reduces postoperative deficits. Spine J. 2018;18:1763–78.

    Article  Google Scholar 

  67. Schirmer CM, Shils JL, Arle JE, Cosgrove GR, Dempsey PK, Tarlov E, et al. Heuristic map of myotomal innervation in humans using direct intraoperative nerve root stimulation. J Neurosurg Spine. 2011;15(1):64–70.

    Article  PubMed  Google Scholar 

  68. Ulkatan S, Neuwirth M, Bitan F, Minardi C, Kokoszka A, Deletis V. Monitoring of scoliosis surgery with epidurally recorded motor evoked potentials (D wave) reveal false results. Clin Neurophysiol. 2006;117:2093–101.

    Article  CAS  PubMed  Google Scholar 

  69. Deletis V. The ‘motor’ inaccuracy in neurogenic motor evoked potentials. Clin Neurophysiol. 2001;112:1365–6.

    Article  CAS  PubMed  Google Scholar 

  70. Toleikis JR, Skelly JP, Carlvin AO, Burkus JK. Spinally elicited peripheral nerve responses are sensory rather than motor. Clin Neurophysiol. 2000;111(4):736–42.

    Article  CAS  PubMed  Google Scholar 

  71. Shils JL, Arle JE. Intraoperative neurophysiological methods for spinal cord stimulator placement under general anesthesia. Neuromodulation. 2012;15(6):560–71.

    Article  PubMed  Google Scholar 

  72. Toleikis JR, Skelly JP, Carlyin AO, Burkus JK. Spinally elicited peripheral nerve responses are sensory rather than motor. Clin Neurophysiol. 2000;111:736–42.

    Article  CAS  PubMed  Google Scholar 

  73. Shils JL, Arle JE. Intraoperative neurophysiologic methods for spinal cord stimulator placement under general anesthesia. Neuromodulation. 2012;15(6):560–72.

    Article  PubMed  Google Scholar 

  74. MacDonald DB. Safety of intraoperative transcranial electric stimulation motor evoked potential monitoring. J Clin Neurophysiol. 2002;19(5):416–29.

    Article  PubMed  Google Scholar 

  75. Ulkatan S, Jaramillo AM, Tellez MJ, Kim J, Deletis V, Seidel K. Incidence of intraoperative seizures during motor evoked potentials monitoring in a large cohort of patients undergoing different surgical procedures. J Neurosurg. 2017;126(4):1296–302.

    Article  PubMed  Google Scholar 

  76. Szelényi A, Joksimovic B, Seifert V. Intraoperative risk of seizures associated with transient direct cortical stimulation in patients with symptomatic epilepsy. J Clin Neurophysiol. 2006;23(6):1–5.

    Google Scholar 

  77. Sartorius CJ, Berger MS. Rapid termination of intraoperative stimulus-evoked seizures with application of cold Ringer’s lactate to the cortex. J Neurosurg. 1998;88:349–51.

    Article  CAS  PubMed  Google Scholar 

  78. Zorzo F, Saltarini M, Bonassin P, et al. Anesthetic management in awake craniotomy. Signa Vitae. 2008;3 Suppl 1:S28–32.

    Google Scholar 

  79. Sloan TB, Jantti V. Anesthetic effects on evoked potentials. In: Nuwer M, editor. Intraoperative monitoring of neural function: handbook of clinical neurophysiology, vol. 8. New York: Elsevier; 2008.

    Chapter  Google Scholar 

  80. Stoelting RK, Hiller SC. Pharmacology and physiology in anesthetic practice. Philadelphia: Lippincott, Williams and Wilkins; 2006.

    Google Scholar 

  81. Deletis V, Sala F. Intraoperative neurophysiological monitoring of the spinal cord during spinal cord and spine surgery: a review focus on the corticospinal tracts. Clin Neurophysiol. 2008;119:248–65.

    Article  PubMed  Google Scholar 

  82. Quraishi NA, Lewis SJ, Kelleher ME, Sarjeant R, Rampersaud YR, Fehlings MG. Intraoperative multimodality monitoring in adult spinal deformity analysis of a prospective series of one hundred two cases with independent evaluation. Spine. 2009;34:1504–12.

    Article  PubMed  Google Scholar 

  83. van Dongen EP, Schepens MA, Morshuis WJ, ter Beek HT, Aarts LP, de Boer A, et al. Thoracic and thoracoabdominal aortic aneurysm repair: use of evoked potential monitoring in 118 patients. J Vasc Surg. 2001;34:1035–40.

    Article  PubMed  Google Scholar 

  84. Neuloh G, Schramm J. Monitoring of motor evoked potentials compared with somatosensory evoked potentials and microvascular Doppler ultrasonography in cerebral aneurysm surgery. J Neurosurg. 2004;100:389–99.

    Article  PubMed  Google Scholar 

  85. Sala F, Bricolo A, Faccioli F, Lanteri P, Gerosa M. Surgery for intramedullary spinal cord tumors: the role of intraoperative (neurophysiological) monitoring. Eur Spine J. 2007;16(suppl 2):S130–9.

    Article  Google Scholar 

  86. Yamamoto T, Katayama Y, Nagaoka T, Kobayashi K, Fukaya C. Intraoperative monitoring of the corticospinal motor evoked potential (D-wave): clinical index for postoperative motor function and functional recovery. Neurol Med Chir (Tokyo). 2004;44:170–80.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Rush University Medical Center, Chicago, IL, USA

    Jay L. Shils

  2. Rush University, Department of Anesthesiology, Chicago, IL, USA

    Jay L. Shils

  3. Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia

    Vedran Deletis

  4. Albert Einstein College of Medicine, New York, NY, USA

    Vedran Deletis

Authors
  1. Jay L. Shils
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Vedran Deletis
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Jay L. Shils .

Editor information

Editors and Affiliations

  1. Department of Anesthesiology, Louisiana State University School of Medicine, Tulane University School of Medicine, New Orleans, LA, USA

    Scott Francis Davis

  2. Departments of Anesthesiology and Pharmacology, Toxicology, and Neurosciences, LSU School of Medicine, Shreveport, LA, USA

    Alan David Kaye

Review Questions

Review Questions

  1. 1.

    Describe how D-waves and I-waves work together to create activation of the alpha motor neuron.

  2. 2.

    How does anesthesia inhibit activation of the alpha motor neuron and what stimulation techniques can overcome this effect?

  3. 3.

    How can you assist a surgeon who is concerned that his tumor resection margins may be too close to the CST as it passes through the internal capsule?

  4. 4.

    What would you tell a surgeon if you were monitoring both TcMEPs and D-waves and saw a loss of MEP responses but a less than 50% change in D-wave amplitude?

  5. 5.

    Why are the most distal muscles preferred recording sites for TcMEP monitoring?

Rights and permissions

Reprints and permissions

Copyright information

© 2020 Springer Nature Switzerland AG

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

Shils, J.L., Deletis, V. (2020). Motor Evoked Potentials. In: Davis, S., Kaye, A. (eds) Principles of Neurophysiological Assessment, Mapping, and Monitoring. Springer, Cham. https://doi.org/10.1007/978-3-030-22400-4_7

Download citation

  • DOI: https://doi.org/10.1007/978-3-030-22400-4_7

  • Published:

  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-030-22399-1

  • Online ISBN: 978-3-030-22400-4

  • eBook Packages: MedicineMedicine (R0)

Publish with us

Policies and ethics

Search

Navigation