Optical heart ratemonitoring - uses and pitfalls

Transcription

1 Optical heart ratemonitoring - uses and pitfalls June 15, 2016

2 PulseOn Offering OHR Tracker White label product for HR/HRV and activity tracking Easy to use with one button only Extended battery life for continuous HR up to 7 days Bluetooth Smart and ANT+ Technology License Turnkey solution from concept all the way to production Reference design for HW and sensor Embedded SW and algorithms Bluetooth Smart and ANT+ OHR Sensor Modules Dynamic low power multiwavelentgh PPG Highly optimized optomechanical design Swiss watch and smart watch options

3 2018 Cuffless blood pressure (product) Parameter roadmap SpO2 (product) - Medical approval - Sleep detection - Respiration rate - Stress and recovery Precise HRV - 24/7 low power OHR - Speed and distance Sports OHR - Steps, activity - Training effect - VO2Max - %VO2, EE - Recovery time

4 Why Optical Heart Rate? 1. The best sensor is the one which is used Replace - chest belt? Replace activity monitor? Replace no monitor? 2. Comfort and acceptability New users regular exercisers during training who do not want chest belt (esp. women) Importance of recovery from top atheletes to average-joe 3. Because we can! Accuracy and coverage improving rapidly Power consumption and size going down gradually

5 Wrist OHR per 2015 PulseOn Score <10bpm MAPE Rest 97,5 2.9 Walking 91,2 4.0 Running 99,0 1.5 Cycling 95,1 2.6 Global 94,4 3.2 Mio LINK Score <10bpm MAPE Rest 97,4 2.6 Walking 73,7 9.8 Running 99,8 0.9 Cycling 97,0 2.0 Global 86,6 5.6 Ricard Delgado-Gonzalo, Jakub Parak, Adrian Tarniceriu, Philippe Renevey, Mattia Bertschi, and Ilkka Korhonen. Evaluation of Accuracy and Reliability of PulseOn Optical Heart Rate Monitoring Device. EMBC 2015.

6 Sports performance in realistic outdoor activities Ricard Delgado-Gonzalo, Jakub Parak, Adrian Tarniceriu, Philippe Renevey, Mattia Bertschi, and Ilkka Korhonen. Evaluation of Accuracy and Reliability of PulseOn Optical Heart Rate Monitoring Device. EMBC 2015.

7 Heart rate [bpm] Heart rate [bpm] PulseOn HR maximal voluntary exercise test Heart rate during speed up laboratory running Heart rate during speed up laboratory running Time [s] Time [s]

8 Estimation of fitness level (VO2Max) with a phone and wrist OHR device Self-paced run (moderate to vigorous, >20min) Wrist OHR VO2Max MAPE 5,2% Sync Phone App + GPS Your VO2Max is 42,6 mg/ml/kg!

9 VO2Max and Energy Expenditure PulseOn OHR + Firstbeat HRV analytics Automated VO2Max estimation during self-paced outdoor running using phone GPS for speed Scientific validation against respiratory gas analysis in controlled sports laboratory testing Similar accuracy as with chest strap HR VO2Max error 5.2% EE error 6.7% in aerobic range EE error 15-20% below aerobic range larger due to physiological factors. Compare to activity trackers error even ~30-100% PulseOn vs respiratory gas analysis based VO2Max All (n=24) Male (n=13) Female (n=11) Bias (ml*kg -1 *min -1 ) MAE 3 (ml*kg -1 *min -1 ) MAPE 4 5.2% 4.7% 5.8% Statistical test p=0.059(w) p=0.082(t) p=0.416(t) Correlation coefficient 0.86**(S) 0.77**(P) 0.69*(P) PulseOn vs respiratory gas analysis based EE Activity All (n=23) Male (n=12) Female (n=11) Bias (kcal) MAE 3 (kcal) MAPE 4 6.7% 8.2% 5.1% Stat tests p<0.007**(t) p=0.081(t) p=0.001**(t) Corr. coef. 0.97**(P) 0.93**(P) 0.99**(P) Scientific validation: Parak J et al. Estimation of Heart Rate, Energy Expenditure and Physical Performance with Wrist Photoplethysmographic Device During Running (submitted for publication)

10 Low power semi-continuous HR monitoring Algorithm for rapid HR acquisition to save power in 24/7 HR trending Reliable HR available in 7-10s when optical chain is activated Error similar to continuous mode HR sample 1/2min power reduction >90% Sensor active time on average 10/120 = ~8,3% Scientific validation: Tarniceriu et al. Towards 24/7 Continuous Heart Rate Monitoring (submitted for publication in EMBC2016)

11 RRI [ms] Best on market optical heart rate variability acquisition Accurate beat-to-beat heart rate detection during sleep 99,6% of beats detected correctly during sleep in 11 volunteers Mean absolute error only 6ms Allows reliable monitoring of stress and recovery Comparison with ECG-based analysis shows high correlation (Firstbeat analytics) PulseOn (PPG Based) vs. Reference (ECG Based) RRI detection PulseOn Original PulseOn B2B Corrected Firstbeat BG2 ECG Reference Scientific validation: Parak J et al. Evaluation of the Beat-to-Beat Detection Accuracy of PulseOn. Wearable Optical Heart Rate Monitor. EMBC Time [s]

12 PulseOn enables HRV based analysis of stress and recovery Lifestyle assessment using Firstbeat Bodyguard (ECG based) Lifestyle assessment using PPG data (PulseOn)

13 Pitfalls

14 Recipe for good quality OHR Mechanics = good and stable fit of the sensor on skin in all conditions, no variation in pressure, optimal pressure Well-designed optomechanics no ambient light distortion, cross-talk Low noise low power electronics for ambient light rejection, good SNR Advanced algorithms to detect HR from noise when SNR is <1% Understanding physiology = blood perfusion in the sensor area has critical impact Mechanical design Client according to PulseOn recommentdations Signal acquisition and pre-processing PulseOn IP (SW + algo) Electronics design PulseOn reference design Algorithms PulseOn IP (SW + algo)

15 Skin structure and blood flow depth varies mm (melanin) 0.6-3mm (nerves, blood vessels blood 0.2-7% of volume) Up to 3cm (fat) Blood flow we want to measure occurs in epidermis which is 0.6-3mm deep. Papillary dermis top layer small arteries which constrict when cold. Reticular dermis bottom layer larger arteries which are less sensitive to cold. Deeper tissues are mostly just fat and add artefacts.

16 Hand still Hand still Hand still Hand still Close and open fist Walking Finger tapping Typing Motion artefacts

17 Elastic vs too rigid strap Rigid strap Elastic strap (Reference failed until 1100s ignore)

18 Ambient light rejection The worst AFE The best AFE

19 Poor perfusion optomechanical design

20 Polar A360 DC Rainmaker

21 Garmin Vivosmart HR cold weather run DC Rainmaker

22 Garmin Vivosmart HR outdoor cycling DC Rainmaker

23 Fitbit Charge HR

24 Fitbit Surge vs PulseOn Data from CSEM

25 Running outdoor dry skin at the beginning of the exercise chest strap tracking cadence until ~4mins

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27 Research needs Objective validation of available wearable devices use in more serious applications such as disease prevention & management, corporate wellness, etc Standardized (& representative protocols) Representative set of subjects Standardized metrics Accuracy & power consumption HR, HRV Integration with other sensor data Evaluation and optimization for special groups Disease groups Age groups Special usage situations Identification of heart dysfunctions (arhhythmias, etc)

28 Contact: Ilkka Korhonen, CTO