Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry.

Calculation of peripheral capillary oxygen saturation [Formula: see text] levels in humans is often made with a pulse oximeter, using photoplethysmography (PPG) waveforms. However, measurements of PPG waveforms are susceptible to motion noise due to subject and sensor movements. In this study, we compare two [Formula: see text]-level calculation techniques, and measure the effect of pre-filtering by a heart-rate tuned comb peak filter on their performance.

Correlation of Cognitive Scores and the Onset of Hypoxia.

The negative effects of hypoxia on human cognitive function have been well documented. In this study we assess the correlation of performance in the SynWin cognitive Multi-Task Battery (MTB) and the onset of hypoxia and describe the use of cognitive assessment scores for real-time hypoxia detection. We performed a correlation analysis between MTB scores (Arithmetic, Memory, Audio Monitoring, Video Monitoring tasks) and blood oxygen saturation levels to discover if the scores are good candidates to detect hypoxia.

Ensemble Learning Approach via Kalman Filtering for a Passive Wearable Respiratory Monitor.

Objective: Utilizing passive radio frequency identification (RFID) tags embedded in knitted smart-garment devices, we wirelessly detect the respiratory state of a subject using an ensemble-based learning approach over an augmented Kalman-filtered time series of RF properties.

Methods: We propose a novel approach for noise modeling using a "reference tag," a second RFID tag worn on the body in a location not subject to perturbations due to respiratory motions that are detected via the primary RFID tag. The reference tag enables modeling of noise artifacts yielding significant improvement in detection accuracy.

Real-Time Hypoxia Prediction Using Decision Fusion.

Humans who operate in high altitudes for prolonged durations often suffer from hypoxia. The commencement of physiological and cognitive changes due to the onset of hypoxia may not be immediately apparent to the exposed individual. These changes can go unrecognized for minutes and even hours and may lead to serious performance degradation or complete incapacitation.