Validation and Verification
Investigation of Photoplethysmography Behind the Ear for Pulse Oximetry in Hypoxic Conditions with a Novel Device (SPYDR)
"We investigated the accuracy of a clinically novel PPG site using SPYDR®, a new PPG sensor suite, against arterial blood gas (ABG) measurements as well as other commercial PPG sensors at the finger and forehead in hypoxic environments. SPYDR utilizes a reflectance PPG sensor applied behind the ear, between the pinna and the hairline, on the mastoid process, above the sternocleidomastoid muscle, near the posterior auricular artery in a self-contained ear cup system. ABG revealed accuracy of SPYDR with a root mean square error of 2.61% at a 70–100% range, meeting FDA requirements for PPG sensor accuracy."
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Acoustic Assessment: SPYDR
"This study was a direct comparison of legacy earcups and SPYDR earcups worn in combination with the HGU-55/P flight helmet and oxygen mask. Data collected
28-30 June, 2022."
"Overall, based on the acoustic assessment, the SPYDR earcups would be considered an acceptable replacement for the legacy earcups."
Data Analytics
Raw Data
Raw data consists of digital signals captured by both FDA-approved and non-FDA-approved sensors. These signals represent electrical activity measured by the sensors and are packaged according to the sensor manufacturer’s specifications. Data is securely stored in encrypted binary files.
Translated Data
Binary data is converted into a structured Comma‑Separated Values (CSV) format, making it accessible for analysis. This includes key data streams such as photoplethysmography (PPG) waveforms, six degrees of freedom (6DoF) acceleration data, and temperature pressure. During this stage, proprietary algorithms from the sensor manufacturer are applied to reduce motion artifacts and improve signal reliability.
Processed Data
Translated data is then cleaned and organized to ensure accuracy and usability.
Confidence scoring is determined using multiple factors, including physiological plausibility (e.g., ambient pressure vs. oxygen levels), rate of change, expected variability, cross-sensor validation, and advanced 6DoF accelerometer signal processing.
Analyzed Data
Processed data is further refined using advanced analytics to generate meaningful insights and metrics.
Flight Parameters:
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Takeoff and landing detection
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Cabin pressure
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Acceleration (G-force)
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Mass airflow
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Oxygen quantity
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Air pressure
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Humidity
Physiological Metrics:
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Heart rate and heart rate variability
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Blood oxygen saturation (SpO₂)
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Breathing and depth rate
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Skin and sensor temperature
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Head movement