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A numerical study to compare stimulations by intraoperative microelectrodes and chronic macroelectrodes in the DBS technique.

Paffi A, Apollonio F, Puxeddu MG, Parazzini M, d'Inzeo G, Ravazzani P, Liberti M - Biomed Res Int (2013)

Bottom Line: Deep brain stimulation is a clinical technique for the treatment of parkinson's disease based on the electric stimulation, through an implanted electrode, of specific basal ganglia in the brain.Here, we used numerical simulations to predict the stimulation of neuronal fibers induced by microelectrodes and macroelectrodes placed in different positions with respect to each other.Otherwise, some groups of fibers may experience a completely different electric stimulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Information Engineering, Electronics and Telecommunication, Sapienza University of Rome, 00184 Rome, Italy ; Italian Inter-University Center for the Study of Electromagnetic Fields and Biological Systems (ICEmB), 16145 Genova, Italy.

ABSTRACT
Deep brain stimulation is a clinical technique for the treatment of parkinson's disease based on the electric stimulation, through an implanted electrode, of specific basal ganglia in the brain. To identify the correct target of stimulation and to choose the optimal parameters for the stimulating signal, intraoperative microelectrodes are generally used. However, when they are replaced with the chronic macroelectrode, the effect of the stimulation is often very different. Here, we used numerical simulations to predict the stimulation of neuronal fibers induced by microelectrodes and macroelectrodes placed in different positions with respect to each other. Results indicate that comparable stimulations can be obtained if the chronic macroelectrode is correctly positioned with the same electric center of the intraoperative microelectrode. Otherwise, some groups of fibers may experience a completely different electric stimulation.

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Relative positions of the microelectrode with respect to the macroelectrode one (not in scale). (a) Position 1, with the same electric center; (b) position 2, with the external surfaces of the cathodes coincident.
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fig3: Relative positions of the microelectrode with respect to the macroelectrode one (not in scale). (a) Position 1, with the same electric center; (b) position 2, with the external surfaces of the cathodes coincident.

Mentions: The value of 50 cm was evaluated in [18] by considering the variations with the box size of V, averaged over the STN volume (Vmean), for a monopolar stimulation (one active contact of the electrode set to −1 V). Figure 2, whose data are taken from Figure 3 of [18], shows the estimated Vmean versus the box size, for two different boundary conditions, that is, with the ground on the whole lateral surface (whole) or on one face (side). In the “whole” ground condition, Vmean decreases and tends to saturate for increasing box dimensions; in particular, changes are less than 1% if the box side is at least 50 cm. Similar percentages are obtained in the “side” condition, even if Vmean increases with the box dimensions. Therefore, a box 50 × 50 × 50 cm3 has been chosen for numerical simulations as the best compromise between computational effort and solution accuracy. Such a choice seems also the most appropriate from an anatomical point of view being 25 cm a reasonable “average” distance between the electrode in the center of the brain and the case of the stimulator in the subclavicular region.


A numerical study to compare stimulations by intraoperative microelectrodes and chronic macroelectrodes in the DBS technique.

Paffi A, Apollonio F, Puxeddu MG, Parazzini M, d'Inzeo G, Ravazzani P, Liberti M - Biomed Res Int (2013)

Relative positions of the microelectrode with respect to the macroelectrode one (not in scale). (a) Position 1, with the same electric center; (b) position 2, with the external surfaces of the cathodes coincident.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814092&req=5

fig3: Relative positions of the microelectrode with respect to the macroelectrode one (not in scale). (a) Position 1, with the same electric center; (b) position 2, with the external surfaces of the cathodes coincident.
Mentions: The value of 50 cm was evaluated in [18] by considering the variations with the box size of V, averaged over the STN volume (Vmean), for a monopolar stimulation (one active contact of the electrode set to −1 V). Figure 2, whose data are taken from Figure 3 of [18], shows the estimated Vmean versus the box size, for two different boundary conditions, that is, with the ground on the whole lateral surface (whole) or on one face (side). In the “whole” ground condition, Vmean decreases and tends to saturate for increasing box dimensions; in particular, changes are less than 1% if the box side is at least 50 cm. Similar percentages are obtained in the “side” condition, even if Vmean increases with the box dimensions. Therefore, a box 50 × 50 × 50 cm3 has been chosen for numerical simulations as the best compromise between computational effort and solution accuracy. Such a choice seems also the most appropriate from an anatomical point of view being 25 cm a reasonable “average” distance between the electrode in the center of the brain and the case of the stimulator in the subclavicular region.

Bottom Line: Deep brain stimulation is a clinical technique for the treatment of parkinson's disease based on the electric stimulation, through an implanted electrode, of specific basal ganglia in the brain.Here, we used numerical simulations to predict the stimulation of neuronal fibers induced by microelectrodes and macroelectrodes placed in different positions with respect to each other.Otherwise, some groups of fibers may experience a completely different electric stimulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Information Engineering, Electronics and Telecommunication, Sapienza University of Rome, 00184 Rome, Italy ; Italian Inter-University Center for the Study of Electromagnetic Fields and Biological Systems (ICEmB), 16145 Genova, Italy.

ABSTRACT
Deep brain stimulation is a clinical technique for the treatment of parkinson's disease based on the electric stimulation, through an implanted electrode, of specific basal ganglia in the brain. To identify the correct target of stimulation and to choose the optimal parameters for the stimulating signal, intraoperative microelectrodes are generally used. However, when they are replaced with the chronic macroelectrode, the effect of the stimulation is often very different. Here, we used numerical simulations to predict the stimulation of neuronal fibers induced by microelectrodes and macroelectrodes placed in different positions with respect to each other. Results indicate that comparable stimulations can be obtained if the chronic macroelectrode is correctly positioned with the same electric center of the intraoperative microelectrode. Otherwise, some groups of fibers may experience a completely different electric stimulation.

Show MeSH
Related in: MedlinePlus