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Difference between revisions of "Trigeminal Nervous System Segmentation"
Trigeminal Nervous System Segmentation (view source)
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<translate>In order to achieve this target, synchronicity, symmetry, and the pulse maximum power are essential</translate>. <translate>This is why electromyographers must be used for evoked potential and they must be equipped with two independent and autonomous high voltage electrostimulators</translate>. <translate>The EMGs that employ tools with a single multiplexated electrostimulator to deliver two or more stimuli are not appropriated</translate>: <translate>the second impulse would lose synchronicit, because the condensers need time to recharge</translate> (<translate>Figure</translate> 2). | <translate>In order to achieve this target, synchronicity, symmetry, and the pulse maximum power are essential</translate>. <translate>This is why electromyographers must be used for evoked potential and they must be equipped with two independent and autonomous high voltage electrostimulators</translate>. <translate>The EMGs that employ tools with a single multiplexated electrostimulator to deliver two or more stimuli are not appropriated</translate>: <translate>the second impulse would lose synchronicit, because the condensers need time to recharge</translate> (<translate>Figure</translate> 2). | ||
[[File:FEM.jpg|left|thumb|'''<translate>Figure</translate> 3:''' Electrophysiological procedure for trigeminal evoked potentials and intracranial diffusion of the induced electric field. ]] | [[File:FEM.jpg|left|thumb|'''<translate>Figure</translate> 3:''' <translate>Electrophysiological procedure for trigeminal evoked potentials and intracranial diffusion of the induced electric field</translate>. ]] | ||
We carry out an analysis made through a generic finite element processor (FE, SimNibs method) to study the distribution of the electric field within the intracranial brain tissue, even if only as a descriptive model ( | <translate>We carry out an analysis made through a generic finite element processor (FE, SimNibs method) to study the distribution of the electric field within the intracranial brain tissue, even if only as a descriptive model</translate> (<translate>Figure</translate> 3)<ref>{{cita libro | ||
| autore = Windhoff M | | autore = Windhoff M | ||
| autore2 = Opitz A | | autore2 = Opitz A | ||
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}}</ref>. | }}</ref>. | ||
The EF models of the study consist of about 1.7 million tetrahedra. | <translate>The EF models of the study consist of about 1.7 million tetrahedra</translate>. T<translate>he Mesh resolution was selectively improved in the regions of the Grey Matter (GM), White Matter (WM), skull, and cerebrospinal fluid (CSF), with an average tetrahedron volume of 1 mm</translate><sup>3</sup>. | ||
Electrical conductibility has been assigned to different types of the affected tissues in which | <translate>Electrical conductibility has been assigned to different types of the affected tissues in which</translate> | ||
<math>\sigma_{Skin} =0.465 S/m;\sigma_{Skull} =0.010 S/m;\sigma_{CSF} =1.654 S/m;\sigma_{GM} =0.276 S/m;\sigma_{WM} =0.126 S/m; </math><ref>{{cita libro | <math>\sigma_{Skin} =0.465 S/m;\sigma_{Skull} =0.010 S/m;\sigma_{CSF} =1.654 S/m;\sigma_{GM} =0.276 S/m;\sigma_{WM} =0.126 S/m; </math><ref>{{cita libro | ||
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}}</ref>. | }}</ref>. | ||
Figure 3A shows the position of the electrodes (<translate>Figure</translate> 12A); the maximum current will spread under the cathodes (red in colour) in the parietal cortex (Figure 3B); in the cranial cortex region, near the trigeminal motor root, the current density is of low magnitude (<translate>Figure</translate> 3C, black arrows). Figure 3D shows the current density that spreads in the brain tissue. It underlines the least amount of electrical current within the brain tissue necessary to saturate the trigeminal motor (relative to the amount required to evoke a response of the trigeminal motor cortex under the cathode). This is one of the reasons that urged us to choose this kind of evoked response (absolutely peripheral) rather than the cortical one (with higher threshold, lower stability, and less focus). | <translate>Figure 3A shows the position of the electrodes</translate> (<translate>Figure</translate> 12A); <translate>the maximum current will spread under the cathodes (red in colour) in the parietal cortex</translate> (<translate>Figure</translate> 3B); <translate>in the cranial cortex region, near the trigeminal motor root, the current density is of low magnitude</translate> (<translate>Figure</translate> 3C, <translate>black arrows</translate>). <translate>Figure 3D shows the current density that spreads in the brain tissue</translate>. <translate>It underlines the least amount of electrical current within the brain tissue necessary to saturate the trigeminal motor (relative to the amount required to evoke a response of the trigeminal motor cortex under the cathode)</translate>. <translate>This is one of the reasons that urged us to choose this kind of evoked response (absolutely peripheral) rather than the cortical one</translate> (<translate>with higher threshold, lower stability, and less focus</translate>). | ||
With this approach | <translate>With this approach we concluded that, given the emergence of the trigeminal root in oval foramen and the distance from the parietal bone and parietal cortical area, the cathode positioning should be more caudal than the regulation</translate> (11–<translate>13 cm on the acoustic-meacoustic line</translate>): <translate>immediately above the upper edge of the ear</translate>. <translate>The position of the cathode, therefore, will be approximately more than the starndard 13–15 cm and will be delimited by the upper margin of the ear</translate>. | ||
Considering the safety limits, the energy provided for each individual impulse in our application will follow this formula: | <translate>Considering the safety limits, the energy provided for each individual impulse in our application will follow this formula</translate>: | ||
<math>E=\bigtriangleup t =R \times I^2 \times \bigtriangleup t = 2.5 mJ </math>per impuls.[[File:Potenziale Evocato della Radice Trigeminale.jpg|thumb|'''Figure 4:''' By increasing the stimulus delivery, more fibers are gradually recruited until saturation.]] | <math>E=\bigtriangleup t =R \times I^2 \times \bigtriangleup t = 2.5 mJ </math>per impuls.[[File:Potenziale Evocato della Radice Trigeminale.jpg|thumb|'''Figure 4:''' By increasing the stimulus delivery, more fibers are gradually recruited until saturation.]] | ||