Integrated FES Orthosis with Reversible Electrode Mounting
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Solution Overview
Problem
Current gait modulation systems, particularly those using functional electrical stimulation (FES) orthoses, face challenges such as cumbersome design, difficulty in donning with impaired hands, limited adaptability to different limb sizes, and discomfort due to high skin current density, which restricts their widespread use for conditions like drop foot.
Innovation Solution
A semi-rigid, self-retaining C-shaped orthosis with flexible retaining elements and large surface area electrodes, integrated with a stimulator unit and a foot sensor device that can be easily donned and adjusted for various limb sizes, reducing skin current density and enhancing ankle torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If prior art external FES devices use a stimulator unit physically separate from the orthosis with electrical wires connecting components, then the device can be controlled externally, but the device becomes cumbersome and inconvenient for the user
Solution Approach 1:
The stimulator unit is integrated directly into the orthosis structure, merging previously separate components (orthosis and stimulator) into a single unified device. This eliminates the need for external wiring and makes the device self-contained, directly resolving the contradiction between ease of operation and device complexity.
2Reliability
If FES orthosis electrodes are positioned precisely for each individual patient, then stimulation effectiveness is optimized, but the device becomes limited to that individual and requires considerable expertise to reconfigure for another patient
Solution Approach 1:
The orthosis is designed with universal adaptability features including adjustable components and reconfigurable electrode positioning systems that can accommodate different patient anatomies. This allows the same device to be effectively used across multiple patients while maintaining optimized stimulation, resolving the contradiction between reliability and adaptability.
3Reliability
If FES orthosis is custom-fitted to individual anatomy and needs, then optimal performance is achieved, but the fitting process is time-consuming and requires considerable expertise
Solution Approach 1:
The orthosis incorporates pre-configured electrode positions and pre-adjusted components designed to work effectively across a range of anatomies. This preliminary configuration reduces the time and expertise needed during actual fitting while maintaining optimal performance, as the device comes pre-prepared for common anatomical variations.
4Volume of moving object
If small electrodes are used in prior art orthosis, then the orthosis can be compact, but skin current density becomes high causing sensory discomfort
Solution Approach 1:
The invention changes the electrode size parameter from small to large surface area electrodes. This parameter change directly reduces skin current density and associated sensory discomfort, while the overall orthosis remains compact through efficient spatial arrangement of the larger electrodes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables effortless donning and secure fitting of the orthosis, reduces skin sensory discomfort, and improves ankle torque generation, making it universally adaptable for diverse users while maintaining even pressure and stability during gait.
Implementation Method 1
In FES, precisely timed bursts of short electrical pulses are applied to motor nerves, to generate muscle contraction, which can be applied to enhancing limb function.
Implementation Method 2
The opposing retaining elements are configured to be radially spring-loaded towards a center of the frame, such that in donning the orthosis around the limb segment, the limb segment applies a counter-pressure from within the frame, against the opposing retaining elements
Data Source
AI summary
An electrical stimulation orthosis and method therefor, the orthosis including: (a) an at least semi-rigid frame configured to substantially envelop a limb segment, the frame having at least one first complementary mechanical fastener associated therewith; (b) a surface electrical stimulation electrode assembly associated with, and supported by, the frame, the assembly having a surface stimulation electrode for contacting at least one stimulation point on the limb segment, the surface electrode assembly having an electrode base for electrically associating, via the frame, with a stimulator unit for providing a stimulation signal to the surface electrode, the electrode base having a top face for receiving the stimulation electrode, and a bottom face having at least one second complementary mechanical fastener, the first and second fasteners adapted for reversible attachment and detachment, at a plurality of locations on the frame, thereby enabling the electrical stimulation electrode assembly to be adjustably and reversibly positioned on the frame.