Sleep-Wakefulness Determination Using Acceleration Scalar Values
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Solution Overview
Problem
Conventional sleep-wakefulness determination methods, such as all-night polysomnography, require numerous measurement devices and are typically conducted in hospitals or laboratories, making it difficult for individuals to test their sleep state accurately over extended periods and causing stress due to the need for multiple electrodes and sensors.
Innovation Solution
A sleep-wakefulness determination apparatus utilizing a bio-acceleration measuring device to calculate scalar values based on acceleration vectors, generating feature values through histogram classification of L2 norms or logarithms, and employing a machine learning model to determine sleep and wakefulness with a reduced number of devices, allowing for accurate assessment in a home environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all-night polysomnography (PSG) test is used to examine sleep state, then measurement precision is improved, but device complexity increases and ease of operation deteriorates
Solution Approach 1:
The invention extracts only the essential feature (body acceleration) from the complex PSG measurement system. Instead of using multiple sensors and electrodes, the patent focuses on a single acceleration sensor to capture the key motion patterns that distinguish sleep and wake states, thereby simplifying the device while maintaining measurement accuracy.
Solution Approach 2:
The invention creates a simplified copy of the sleep examination function using a single acceleration sensor. This copy captures the essential sleep-wake determination capability without requiring the full PSG system, enabling the test to be performed in home environments with minimal equipment.
2Measurement precision
If all-night polysomnography (PSG) test is used to examine sleep state, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The invention extracts only the essential feature (body acceleration) from the complex PSG measurement system. Instead of using multiple sensors and electrodes, the patent focuses on a single acceleration sensor to capture the key motion patterns that distinguish sleep and wake states, thereby simplifying the device while maintaining measurement accuracy.
Solution Approach 2:
The invention enables the user to perform the sleep examination themselves in their own home environment. The simplified system requires no special laboratory setting, and users can wear the device during their natural sleep patterns without external intervention, making the test self-service oriented and more convenient.
3Measurement precision
If multiple electrodes and sensors are attached to the body for PSG test, then measurement precision is improved, but object-affected harmful factors increase
Solution Approach 1:
The invention extracts only the essential feature (body acceleration) from the complex PSG measurement system. Instead of using multiple sensors and electrodes, the patent focuses on a single acceleration sensor to capture the key motion patterns that distinguish sleep and wake states, thereby simplifying the device while maintaining measurement accuracy.
4Measurement precision
If PSG test is performed in hospital or laboratory environment, then measurement precision is improved, but adaptability deteriorates
Solution Approach 1:
The invention makes the measurement device universal by enabling it to function in multiple environments (home, hospital, laboratory). The simplified acceleration-based system can be used anywhere without requiring specialized facilities, allowing users to perform sleep examinations in their natural home environment while maintaining examination accuracy.
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
Enables accurate determination of sleep and wakefulness using a minimal number of devices, reducing stress and facilitating testing in a familiar environment, while providing a high degree of accuracy through the use of a wearable device and machine learning algorithms.
Implementation Method 1
an acceleration sensor that measures acceleration in a three-dimensional direction
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
[Problem] To provide a sleep-wakefulness determination device and a program which determine sleep-wakefulness at sufficiently high accuracy by using a small mounting tool. [Solution] According to one aspect of the present invention, provided is a sleep-wakefulness determination device which can determine sleep and wakefulness of a user. The sleep-wakefulness determination device is provided with a scalar calculation unit, a feature amount calculation unit, and a sleep-wakefulness determination unit. The scalar calculation unit is configured to be able to calculate a scalar value on the basis of each component of an acceleration vector in a part of the body of the user. The feature amount calculation unit is configured to be able to calculate, on the basis of the scalar value, a feature amount for each epoch defined as a prescribed time. The sleep-wakefulness determination unit is configured to be able to determine sleep or wakefulness of the user on the basis of the feature amount of a desired epoch among the epochs and the feature amounts of surrounding epochs included in preceding and subsequent epochs of the desired epoch in a time series.