Pulse Wave Sleep Apnea Typing Without Respiratory Movement Sensors
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Solution Overview
Problem
Existing sleep apnea diagnosis methods, such as polysomnography (PSG) tests, require cumbersome sensors that are prone to displacement during sleep, especially in simple PSG tests, leading to instability in respiratory movement detection and inaccurate differentiation between obstructive and central sleep apnea.
Innovation Solution
A biological information processing device that utilizes pulse wave analysis, SpO2 measurement, and respiration waveform detection to identify hypopnea or apnea intervals and determine the presence or absence of respiration effort without relying on abdominal and thoracic region sensors, using a control unit to analyze pulse waves and generate characteristic waveforms to distinguish between obstructive and central sleep apnea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If respiratory movement sensors are attached to abdominal and thoracic regions to detect respiration effort, then sleep apnea differentiation between OSA and CSA becomes possible, but sensor displacement during sleep occurs and detection stability deteriorates
Solution Approach 1:
The patent introduces a flow sensor as an intermediary device that measures respiratory airflow instead of directly measuring respiration effort through body movement sensors. The flow sensor is positioned in the airway and detects airflow changes, which indirectly reflects respiratory effort without requiring direct contact with the abdomen or thorax, thus avoiding sensor displacement issues while maintaining detection accuracy.
Solution Approach 2:
The patent replaces the mechanical body movement detection system (abdominal/thoracic sensors measuring physical movement) with an airflow-based detection system (flow sensor measuring respiratory flow). This substitution eliminates the mechanical contact issues and displacement problems inherent in body-worn sensors while providing more stable and reliable respiration effort detection throughout sleep.
2Ease of operation
If simple PSG test is performed with minimal sensors to reduce subject burden, then ease of operation improves, but accurate differentiation between OSA and CSA becomes difficult
Solution Approach 1:
The patent makes the flow sensor multi-functional by using it to detect both respiratory effort (for OSA/CSA differentiation) and airflow characteristics (for apnea/hypopnea detection). This single sensor performs multiple measurement functions that would traditionally require separate sensors, maintaining measurement precision while simplifying the overall system and reducing subject burden.
Solution Approach 2:
The patent changes the measurement parameter from direct body movement (abdominal/thoracic expansion) to airflow dynamics (respiratory flow rate and pattern). This parameter change allows the system to infer respiration effort and differentiate sleep apnea types through airflow analysis rather than requiring direct mechanical measurement of body movement, thereby maintaining accuracy with fewer sensors.
3Ease of operation
If respiratory movement sensor is made belt-shaped for easy attachment, then ease of operation improves, but wearing position shifts during sleep and measurement precision deteriorates
Solution Approach 1:
The patent introduces a flow sensor as an intermediary that measures respiratory effort indirectly through airflow detection rather than directly through body movement. This eliminates the need for belt-shaped sensors that shift position, as the flow sensor is positioned in the airway where it can reliably detect respiratory effort changes without being affected by body movement or position shifts.
Solution Approach 2:
The patent replaces the mechanical belt-shaped body movement detection system with an airflow-based detection system. This substitution eliminates the inherent position-shifting problem of wearable belts while maintaining ease of operation through simple airway placement. The airflow measurement provides stable, precise respiration effort detection regardless of sensor position or body movement.
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 identification of sleep apnea types with reduced subject burden by eliminating the need for respiratory movement sensors, improving detection stability and accuracy through pulse wave and SpO2 analysis.
Implementation Method 1
a pulse wave obtained by a pulse oximeter
Implementation Method 2
The respiratory movement sensor detects movement of the thorax or the abdominal wall on the basis of a change in inductance
Implementation Method 3
a change in voltage generated by a piezoelectric film
Data Source
AI summary
A biological information processing device detects a hypopnea or apnea interval in a period of measurement of a pulse wave during sleep. Also, the biological information processing device determines presence or absence of a respiration effort on the basis of the detected pulse wave in the hypopnea or apnea interval. The biological information processing device identifies a type of respiration disorder for the detected hypopnea or apnea interval on the basis of the presence or absence of the respiration effort.