Abstract
The purpose of this study was to test the feasibility of using a switched-capacitor discharge stimulation (SCDS) system for electrical stimulation, and, subsequently, determine the overall energy saved compared to a conventional stimulator. We have constructed a computational model by pairing an image-based volume conductor model of the cat head with cable models of corticospinal tract (CST) axons and quantified the theoretical stimulation efficiency of rectangular and decaying exponential waveforms, produced by conventional and SCDS systems, respectively. Subsequently, the model predictions were tested in vivo by activating axons in the posterior internal capsule and recording evoked electromyography (EMG) in the contralateral upper arm muscles. Compared to rectangular waveforms, decaying exponential waveforms with time constants >500 μs were predicted to require 2%-4% less stimulus energy to activate directly models of CST axons and 0.4%-2% less stimulus energy to evoke EMG activity in vivo. Using the calculated wireless input energy of the stimulation system and the measured stimulus energies required to evoke EMG activity, we predict that an SCDS implantable pulse generator (IPG) will require 40% less input energy than a conventional IPG to activate target neural elements. A wireless SCDS IPG that is more energy efficient than a conventional IPG will reduce the size of an implant, require that less wireless energy be transmitted through the skin, and extend the lifetime of the battery in the external power transmitter.
| Original language | English |
|---|---|
| Pages (from-to) | 1095-1106 |
| Number of pages | 12 |
| Journal | IEEE Transactions on Biomedical Engineering |
| Volume | 65 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2018 May 1 |
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Keywords
- Implantable pulse generator
- stimulation efficiency
- switched-capacitor discharging stimulation
- wireless power transmission
ASJC Scopus subject areas
- Biomedical Engineering
Cite this
Stimulation Efficiency with Decaying Exponential Waveforms in a Wirelessly Powered Switched-Capacitor Discharge Stimulation System. / Lee, Hyung Min; Howell, Bryan; Grill, Warren M.; Ghovanloo, Maysam.
In: IEEE Transactions on Biomedical Engineering, Vol. 65, No. 5, 01.05.2018, p. 1095-1106.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Stimulation Efficiency with Decaying Exponential Waveforms in a Wirelessly Powered Switched-Capacitor Discharge Stimulation System
AU - Lee, Hyung Min
AU - Howell, Bryan
AU - Grill, Warren M.
AU - Ghovanloo, Maysam
PY - 2018/5/1
Y1 - 2018/5/1
N2 - The purpose of this study was to test the feasibility of using a switched-capacitor discharge stimulation (SCDS) system for electrical stimulation, and, subsequently, determine the overall energy saved compared to a conventional stimulator. We have constructed a computational model by pairing an image-based volume conductor model of the cat head with cable models of corticospinal tract (CST) axons and quantified the theoretical stimulation efficiency of rectangular and decaying exponential waveforms, produced by conventional and SCDS systems, respectively. Subsequently, the model predictions were tested in vivo by activating axons in the posterior internal capsule and recording evoked electromyography (EMG) in the contralateral upper arm muscles. Compared to rectangular waveforms, decaying exponential waveforms with time constants >500 μs were predicted to require 2%-4% less stimulus energy to activate directly models of CST axons and 0.4%-2% less stimulus energy to evoke EMG activity in vivo. Using the calculated wireless input energy of the stimulation system and the measured stimulus energies required to evoke EMG activity, we predict that an SCDS implantable pulse generator (IPG) will require 40% less input energy than a conventional IPG to activate target neural elements. A wireless SCDS IPG that is more energy efficient than a conventional IPG will reduce the size of an implant, require that less wireless energy be transmitted through the skin, and extend the lifetime of the battery in the external power transmitter.
AB - The purpose of this study was to test the feasibility of using a switched-capacitor discharge stimulation (SCDS) system for electrical stimulation, and, subsequently, determine the overall energy saved compared to a conventional stimulator. We have constructed a computational model by pairing an image-based volume conductor model of the cat head with cable models of corticospinal tract (CST) axons and quantified the theoretical stimulation efficiency of rectangular and decaying exponential waveforms, produced by conventional and SCDS systems, respectively. Subsequently, the model predictions were tested in vivo by activating axons in the posterior internal capsule and recording evoked electromyography (EMG) in the contralateral upper arm muscles. Compared to rectangular waveforms, decaying exponential waveforms with time constants >500 μs were predicted to require 2%-4% less stimulus energy to activate directly models of CST axons and 0.4%-2% less stimulus energy to evoke EMG activity in vivo. Using the calculated wireless input energy of the stimulation system and the measured stimulus energies required to evoke EMG activity, we predict that an SCDS implantable pulse generator (IPG) will require 40% less input energy than a conventional IPG to activate target neural elements. A wireless SCDS IPG that is more energy efficient than a conventional IPG will reduce the size of an implant, require that less wireless energy be transmitted through the skin, and extend the lifetime of the battery in the external power transmitter.
KW - Implantable pulse generator
KW - stimulation efficiency
KW - switched-capacitor discharging stimulation
KW - wireless power transmission
UR - http://www.scopus.com/inward/record.url?scp=85028382169&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85028382169&partnerID=8YFLogxK
U2 - 10.1109/TBME.2017.2741107
DO - 10.1109/TBME.2017.2741107
M3 - Article
C2 - 28829301
AN - SCOPUS:85028382169
VL - 65
SP - 1095
EP - 1106
JO - IEEE Transactions on Biomedical Engineering
JF - IEEE Transactions on Biomedical Engineering
SN - 0018-9294
IS - 5
ER -