Compact Nonlinear Model of an Implantable Electrode Array for Spinal Cord Stimulation (SCS)

Area of Science:

• Biomedical Engineering
• Computational Modeling
• Electrophysiology

Background:

• Spinal-cord stimulation (SCS) relies on electrode-electrolyte interfaces.
• Accurate modeling of these interfaces is crucial for device optimization.
• Existing models may lack the complexity to capture subtle operational characteristics.

Purpose of the Study:

• To develop a computationally efficient model for the electrode-electrolyte interface in SCS.
• To accurately represent both the bulk electrolyte and the interface dynamics.
• To validate the model against a commercial platinum electrode array.

Main Methods:

• A 2D resistor array model was used for the bulk electrolyte.
• A nonlinear extension incorporating diodes and a memristor modeled the electrode-electrolyte interface.
• The model was fitted to data from a commercial implantable electrode array.

Main Results:

• The 2D resistor array effectively modeled the bulk electrolyte.
• The nonlinear interface model captured current-overpotential characteristics and diffusion limits.
• The model successfully predicted subtle operational characteristics of the commercial array.

Conclusions:

• The developed model provides a satisfactory and computationally suitable representation of the electrode-electrolyte interface for SCS.
• This model can aid in the design and optimization of SCS electrode arrays.
• The model's ability to predict subtle characteristics enhances its utility in practical applications.