Inertial Sensor Spasticity Evaluation Apparatus

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Solution Overview

Problem

Current spasticity evaluations lack consistency and objectivity due to subjective measurement variations, making it difficult to accurately assess spasticity and clonus, which are symptoms of upper motor neuron syndrome.

Innovation Solution

An apparatus and method using an inertia sensor to calculate the angle of a joint based on acceleration and angular velocity measurements, providing objective numerical values for reliable spasticity evaluation, and offering real-time visual biofeedback to adjust velocity independently of user experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If spasticity evaluation is performed based on subjective sense of user, then evaluation can be conducted without additional equipment, but measurement consistency and objectivity deteriorate

Engineering Contradiction:

Improveevaluation simplicityVSAvoidmeasurement consistency

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the subjective mechanical assessment system with an objective inertial sensor-based measurement system. The inertial sensor automatically measures acceleration and angular velocity to calculate joint angle and velocity, eliminating reliance on rater subjectivity while maintaining ease of use through automated data collection and processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an inertial sensor as an intermediary device between the joint movement and the evaluation process. This intermediary objectively captures movement parameters (acceleration, angular velocity, joint angle) that mediate between the physical movement and the spasticity assessment, removing the subjective element while preserving evaluation accessibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If joint angle is calculated using acceleration meter, then measurement is simple, but accuracy deteriorates in dynamic states

Engineering Contradiction:

Improvecalculation simplicityVSAvoidjoint angle accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic measurement system that adapts the calculation method based on the movement state. When the object is in a quasi-static state (low acceleration and angular velocity variation), acceleration-based calculation is used for simplicity. When in a dynamic state (high variation), angular velocity-based integration is used for accuracy, allowing the system to optimize between simplicity and precision based on real-time conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the calculation parameter based on the movement state. The system monitors acceleration and angular velocity variations to determine whether to use acceleration-derived joint angle (for static conditions) or angular velocity-integrated joint angle (for dynamic conditions), thereby optimizing measurement accuracy across different operational states.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If velocity adjustment relies on user experience, then no additional feedback system is needed, but objectivity of velocity adjustment deteriorates

Engineering Contradiction:

Improvefeedback system complexityVSAvoidvelocity adjustment objectivity

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements real-time visual biofeedback by displaying the measured joint velocity on a screen. This feedback loop provides objective numerical velocity information to the user during measurement, enabling accurate velocity adjustment independent of user experience or subjective judgment, while the system automatically manages the feedback display without requiring complex additional hardware.

Inventive Principle:

Principle #23Feedback

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 enhances the reliability and objectivity of spasticity and clonus evaluations by using inertia sensors to calculate joint angles accurately, providing objective data and improving the consistency of measurements, thereby supporting more precise assessments of spasticity and clonus.

Implementation Method 1

an acceleration meter included in the inertia sensor

Methodology Applied

Scientific EffectInertial force detection: Accelerometer

Implementation Method 2

an angular velocity meter included in the inertia sensor

Methodology Applied

Scientific EffectRotational motion detection: Gyroscope

Implementation Method 3

calculate a gradient relative to a ground based on a magnitude of an acceleration with respect to a gravitational acceleration as the angle of the joint

Methodology Applied

Scientific EffectGravitation: Gravitation

Data Source

PatentUS11089976B2Method and apparatus for assisting spasticity and clonus evaluation using inertial sensor

Publication Date: 2021.08.17 DAEGU GYEONGBUK INSTITUTE OF SCIENCE AND TECHNOLOGY

AI summary

Provided is a method and apparatus for assisting spasticity and clonus evaluation using an inertia sensor, the apparatus including an acquirer configured to acquire a measured value from an inertia sensor attached to an object, a calculator configured to calculate an angle of a joint of the object based on the measured value, and a processor configured to evaluate a spasticity and a clonus based on the angle of the joint.