Stand Sit Lie Down Arm Down Arm in Lap Arm at Heart Audio: OFF Play Demo

PPG Signal Quest: The Quality Game

Welcome to PPG Signal Quest! This interactive web application demonstrates how various factors affect the quality of a photoplethysmography (PPG) signal, which is used to measure heart rate and other vital signs from the wrist. The simulation is based on the findings from the scientific paper "Determinants of photoplethysmography signal quality at the wrist" by Charlton et al. A high-quality signal is crucial for accurate health monitoring.

Read the paper: https://doi.org/10.1371/journal.pdig.0000585

How to Play

Your mission is to achieve the highest Signal-to-Noise Ratio (SNR), which represents the quality of the PPG signal. A higher SNR means a cleaner, more reliable signal.

• Adjust Posture: Use the "Stand", "Sit", and "Lie Down" buttons to change the subject's posture.
• Change Arm Position: Use the "Arm Down", "Arm in Lap", and "Arm at Heart" buttons to adjust the height of the measurement arm. Note that some positions are only available in certain postures.
• Observe the Waveform: Watch how the PPG waveform (right side of the canvas) changes. A clean, rhythmic wave indicates good quality, while a noisy, erratic wave indicates poor quality.
• Check the Score: The "Signal Quality (SNR)" at the top right of the canvas gives you a quantitative measure of the signal quality. Try to find the combination of posture and arm position that yields the highest score!
• Audio Feedback: Toggle the audio to hear a sound when the signal quality improves or degrades.
• Keyboard Shortcuts: For faster interaction, use 'T' (stand), 'S' (sit), 'L' (lie down), and Arrow Keys (Up = Arm at Heart, Right = Arm in Lap, Down = Arm Down) for arm position.

Future Directions

This simulation provides a foundation for understanding PPG signal quality. Future versions could be expanded to include a wider range of variables discussed in the research paper and beyond:

• Motion Artifacts: Simulating the effects of walking, running, or other movements on signal quality.
• Physiological Factors: Incorporating variables like skin tone, body mass index (BMI), and blood pressure.
• Hardware Simulation: Adding controls for sensor pressure, LED brightness, and wavelength to see how hardware choices impact the signal.
• Gamification: Introducing specific challenges, leaderboards, and educational scenarios to further engage users.