Effects of transcranial stimulating electrode montages over the head for lower-extremity transcranial motor evoked potential monitoring

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Abstract

OBJECTIVE The aim of this study was to determine the most effective electrode montage to elicit lower-extremity transcranial motor evoked potentials (LE-TMEPs) using a minimum stimulation current. METHODS A realistic 3D head model was created from T1-weighted images. Finite element methods were used to visualize the electric field in the brain, which was generated by transcranial electrical stimulation via 4 electrode montage models. The stimulation threshold level of LE-TMEPs in 52 patients was also studied in a practical clinical setting to determine the effects of each electrode montage. RESULTS The electric field in the brain radially diffused from the brain surface at a maximum just below the electrodes in the finite element models. The Cz-inion electrode montage generated a centrally distributed high electric field with a current direction longitudinal and parallel to most of the pyramidal tract fibers of the lower extremity. These features seemed to be effective in igniting LE-TMEPs. Threshold level recordings of LE-TMEPs revealed that the Cz-inion electrode montage had a lower threshold on average than the C3-C4 montage, 76.5 20.6 mA and 86.2 20.6 mA, respectively (31 patients, t = 4.045, p < 0.001, paired t-Test). In 23 (74.2%) of 31 cases, the Cz-inion montage could elicit LE-TMEPs at a lower threshold than C3-C4. CONCLUSIONS The C3-C4 and C1-C2 electrode montages are the standard for tMEP monitoring in neurosurgery, but the Cz-inion montage showed lower thresholds for the generation of LE-TMEPs. The Cz-inion electrode montage should be a good alternative for LE-TMEP monitoring when the C3-C4 has trouble igniting LE-TMEPs.

Original languageEnglish
Pages (from-to)1951-1958
Number of pages8
JournalJournal of Neurosurgery
Volume126
Issue number6
DOIs
Publication statusPublished - 2017 Jun 1

Fingerprint

Motor Evoked Potentials
Lower Extremity
Electrodes
Head
Brain
Pyramidal Tracts
Neurosurgery

Keywords

  • Diagnostic and operative techniques
  • Electrode montage
  • Lower extremity
  • Neurosurgery
  • Transcranial electric stimulation
  • Transcranial motor evoked potential

ASJC Scopus subject areas

  • Surgery
  • Medicine(all)
  • Clinical Neurology

Cite this

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title = "Effects of transcranial stimulating electrode montages over the head for lower-extremity transcranial motor evoked potential monitoring",
abstract = "OBJECTIVE The aim of this study was to determine the most effective electrode montage to elicit lower-extremity transcranial motor evoked potentials (LE-TMEPs) using a minimum stimulation current. METHODS A realistic 3D head model was created from T1-weighted images. Finite element methods were used to visualize the electric field in the brain, which was generated by transcranial electrical stimulation via 4 electrode montage models. The stimulation threshold level of LE-TMEPs in 52 patients was also studied in a practical clinical setting to determine the effects of each electrode montage. RESULTS The electric field in the brain radially diffused from the brain surface at a maximum just below the electrodes in the finite element models. The Cz-inion electrode montage generated a centrally distributed high electric field with a current direction longitudinal and parallel to most of the pyramidal tract fibers of the lower extremity. These features seemed to be effective in igniting LE-TMEPs. Threshold level recordings of LE-TMEPs revealed that the Cz-inion electrode montage had a lower threshold on average than the C3-C4 montage, 76.5 20.6 mA and 86.2 20.6 mA, respectively (31 patients, t = 4.045, p < 0.001, paired t-Test). In 23 (74.2{\%}) of 31 cases, the Cz-inion montage could elicit LE-TMEPs at a lower threshold than C3-C4. CONCLUSIONS The C3-C4 and C1-C2 electrode montages are the standard for tMEP monitoring in neurosurgery, but the Cz-inion montage showed lower thresholds for the generation of LE-TMEPs. The Cz-inion electrode montage should be a good alternative for LE-TMEP monitoring when the C3-C4 has trouble igniting LE-TMEPs.",
keywords = "Diagnostic and operative techniques, Electrode montage, Lower extremity, Neurosurgery, Transcranial electric stimulation, Transcranial motor evoked potential",
author = "Ryosuke Tomio and Takenori Akiyama and Takayuki Oohira and Kazunari Yoshida",
year = "2017",
month = "6",
day = "1",
doi = "10.3171/2016.7.JNS16643",
language = "English",
volume = "126",
pages = "1951--1958",
journal = "Journal of Neurosurgery",
issn = "0022-3085",
publisher = "American Association of Neurological Surgeons",
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T1 - Effects of transcranial stimulating electrode montages over the head for lower-extremity transcranial motor evoked potential monitoring

AU - Tomio, Ryosuke

AU - Akiyama, Takenori

AU - Oohira, Takayuki

AU - Yoshida, Kazunari

PY - 2017/6/1

Y1 - 2017/6/1

N2 - OBJECTIVE The aim of this study was to determine the most effective electrode montage to elicit lower-extremity transcranial motor evoked potentials (LE-TMEPs) using a minimum stimulation current. METHODS A realistic 3D head model was created from T1-weighted images. Finite element methods were used to visualize the electric field in the brain, which was generated by transcranial electrical stimulation via 4 electrode montage models. The stimulation threshold level of LE-TMEPs in 52 patients was also studied in a practical clinical setting to determine the effects of each electrode montage. RESULTS The electric field in the brain radially diffused from the brain surface at a maximum just below the electrodes in the finite element models. The Cz-inion electrode montage generated a centrally distributed high electric field with a current direction longitudinal and parallel to most of the pyramidal tract fibers of the lower extremity. These features seemed to be effective in igniting LE-TMEPs. Threshold level recordings of LE-TMEPs revealed that the Cz-inion electrode montage had a lower threshold on average than the C3-C4 montage, 76.5 20.6 mA and 86.2 20.6 mA, respectively (31 patients, t = 4.045, p < 0.001, paired t-Test). In 23 (74.2%) of 31 cases, the Cz-inion montage could elicit LE-TMEPs at a lower threshold than C3-C4. CONCLUSIONS The C3-C4 and C1-C2 electrode montages are the standard for tMEP monitoring in neurosurgery, but the Cz-inion montage showed lower thresholds for the generation of LE-TMEPs. The Cz-inion electrode montage should be a good alternative for LE-TMEP monitoring when the C3-C4 has trouble igniting LE-TMEPs.

AB - OBJECTIVE The aim of this study was to determine the most effective electrode montage to elicit lower-extremity transcranial motor evoked potentials (LE-TMEPs) using a minimum stimulation current. METHODS A realistic 3D head model was created from T1-weighted images. Finite element methods were used to visualize the electric field in the brain, which was generated by transcranial electrical stimulation via 4 electrode montage models. The stimulation threshold level of LE-TMEPs in 52 patients was also studied in a practical clinical setting to determine the effects of each electrode montage. RESULTS The electric field in the brain radially diffused from the brain surface at a maximum just below the electrodes in the finite element models. The Cz-inion electrode montage generated a centrally distributed high electric field with a current direction longitudinal and parallel to most of the pyramidal tract fibers of the lower extremity. These features seemed to be effective in igniting LE-TMEPs. Threshold level recordings of LE-TMEPs revealed that the Cz-inion electrode montage had a lower threshold on average than the C3-C4 montage, 76.5 20.6 mA and 86.2 20.6 mA, respectively (31 patients, t = 4.045, p < 0.001, paired t-Test). In 23 (74.2%) of 31 cases, the Cz-inion montage could elicit LE-TMEPs at a lower threshold than C3-C4. CONCLUSIONS The C3-C4 and C1-C2 electrode montages are the standard for tMEP monitoring in neurosurgery, but the Cz-inion montage showed lower thresholds for the generation of LE-TMEPs. The Cz-inion electrode montage should be a good alternative for LE-TMEP monitoring when the C3-C4 has trouble igniting LE-TMEPs.

KW - Diagnostic and operative techniques

KW - Electrode montage

KW - Lower extremity

KW - Neurosurgery

KW - Transcranial electric stimulation

KW - Transcranial motor evoked potential

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