Co-Planar Macro and Micro Electrodes for Brain Surface Sensing
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Solution Overview
Problem
Current cortical strip/grid electrodes are not well-suited for simultaneously sensing cellular activity within the brain and standard electroencephalography (EEG) activity, and they lack ease of placement and stability on the brain surface.
Innovation Solution
A cortical sensing device with a flexibly-conformable support member, incorporating both macroelectrode and microelectrode sensing elements, where the macroelectrode and microelectrode brain-contact surfaces are co-planar to facilitate easy placement and secure contact with the brain, using bio-compatible materials and designs that prevent electrical interaction and ensure secure anchoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cortical strip/grid electrodes are used to monitor EEG activity, then non-invasive monitoring is achieved, but the ability to simultaneously sense cellular activity within the brain is lost
Solution Approach 1:
The electrode is divided into distinct macroelectrode and microelectrode segments that can function independently or together. The macroelectrode contacts the brain surface for EEG recording while microelectrodes can penetrate into the brain tissue for cellular activity sensing, allowing dual functionality from a single device structure.
Solution Approach 2:
The microelectrodes are positioned within or adjacent to the macroelectrode structure, with microelectrode contacts surrounded by macroelectrode contacts. This nested arrangement allows the smaller microelectrodes to be integrated within the larger macroelectrode framework, enabling simultaneous measurement at different tissue depths.
2Adaptability or versatility
If depth electrodes are inserted into the brain to sense cellular activity, then cellular activity monitoring is achieved, but invasive damage to brain tissue occurs
Solution Approach 1:
Instead of inserting deep electrodes throughout the brain, only partial penetration is performed where microelectrodes contact the brain surface or slightly penetrate at specific locations. This partial action provides sufficient cellular activity sensing capability while minimizing invasive damage to the surrounding brain tissue.
3Reliability
If macroelectrode and microelectrode contacts are arranged at some distance from each other, then electrical isolation is achieved, but simultaneous sensing of cellular and EEG activity becomes less accurate
Solution Approach 1:
The microelectrode contacts are positioned within or immediately adjacent to the macroelectrode contacts, creating a nested configuration. This arrangement maintains electrical isolation through the dielectric substrate while ensuring both electrode types contact the brain at essentially the same location, enabling accurate simultaneous measurement of cellular and EEG activity.
4Ease of operation
If cortical sensing devices are placed on the brain surface, then ease of placement is achieved, but unintentional movement of the device occurs
Solution Approach 1:
The electrode strip is designed with flexibility to conform to the curved surface of the brain, following its contours rather than maintaining a rigid flat shape. This curved adaptation improves contact stability and prevents device movement while maintaining ease of placement on the irregular brain surface.
Data Source
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AI summary
A cortical sensing device (10) for contact with the surface of the brain is provided that includes a support member (14), at least one macroelectrode sensing element (18) secured with respect to the support member and at least one microelectrode sensing element (22) secured with respect to the macroelectrode. The support member is substantially thin and made from flexibly-conformable material to accurately and safely place the sensing device upon the brain surface. The microelectrode sensing element is surrounded by the macroelectrode brain-contact surface (20) of the macroelectrode sensing element. The first surface (16) of the support member, the macroelectrode brain-contact surface (20) and the microelectrode brain-contact surface (24) are substantially co-planar to abut the surface of the brain (12) for sensoring and monitoring.