Neural Stimulation Electrodes with Segmented Return Paths
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Solution Overview
Problem
Retinal prosthetic devices face a trade-off between high electrode density for better visual acuity and interference between adjacent stimulating electrodes, necessitating improved methods for neural stimulation to achieve discrete phosphenes.
Innovation Solution
A neural prosthesis with a stimulating electrode array incorporating bipolar and monopolar return electrodes, where the return current is divided between multiple bipolar return paths and a monopolar return path, allowing for a controlled ratio of return currents to minimize interference and enhance stimulation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high density electrode arrays are used to improve visual acuity, then the number of distinguishable phosphenes increases, but interference between adjacent stimulating electrodes increases
Solution Approach 1:
The return current path is segmented into multiple independent pathways: a first return path through bipolar return electrodes and a second return path through monopolar return electrodes. This segmentation allows the return current to be distributed across separate pathways, reducing the current density and interference in the tissue between adjacent stimulating electrodes, thereby enabling higher electrode density without proportional increase in interference.
2Reliability
If multiple return paths are used to reduce interference, then charge containment improves, but device complexity increases
Solution Approach 1:
The electrode array is designed with electrodes that can serve multiple functions: stimulating electrodes can function as both stimulus sources and return paths depending on configuration, and bipolar return electrodes can serve both as local return paths and as part of the overall current distribution system. This multi-functionality reduces the need for dedicated separate components for each function, thereby managing device complexity while achieving improved charge containment through multiple return paths.
Data Source
AI summary
The present invention relates to a neural prosthesis. In its most general form, the neural prosthesis comprises an electrode array including a stimulating electrode (801) and a bipolar return electrode (802). The neural prosthesis also comprises a monopolar return electrode (806), a first electrical return path (812) associated with the bipolar return electrode (802) and a second electrical return path (814) associated with the monopolar return electrode (806) wherein, in use, the stimulating electrode (801) provides a stimulating current to the tissue of a recipient and a total return current is divided between a first current in the first electrical return path (812) and a second current in the second electrical return path (814).