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Continuous Digital Biomarkers from Wearable Devices Brandon Ballinger, @bballinger

@AppCardiogram

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TRADITIONAL BIOMARKERS CONTINUOUS DIGITAL BIOMARKERS

Biomarkers are Becoming Continuous and Digital

Necessary but not fun Engaging

Point-in-time 100,000+ data points per person per year

Clinician-interpreted Hybrid of human and artificial intelligence

Well-understood science based on Framingham (1948) and other historic studies

Emerging field at the intersection of medicine, artificial intelligence, and mobile design.

Fitbit HuaweiApple

Fossil Motorola

What’s your ♡ telling you? Examples from Cardiogram for Apple Watch

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Fitness StressRunning

Hockey

Driving in Rush Hour

Microsoft interview

IllnessAtrial Fibrillation

Atrial Flutter

SleepRestful Sleep

Sleep after Alcohol

Heart rate biomarkers known from the medical literature

Reverse commute(SF to Palo Alto in AM)

Regular commute(SF to Palo Alto in PM)

8:00AM 8:30AM 4:30PM4:00PM

60

100

140Heart rate

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100

140

Heart Rate Variability

11:00AM

80

130

180Heart rate

12:00PM11:30AM

Intense workout StretchingRecovery

Heart Rate Recovery & Resting Heart Rate

HEART RATE RECOVERY

RESTING HR

What can heart rate metrics tell you about yourself?

Metric Associated with (not exhaustive)

Resting heart rate (RHR) (Physical fitness, stress)

• Mortality (1.3x in pts with coronary artery disease)

• Heart attack • Mortality (1.3x women)

Heart rate recovery (HRR) (Physical fitness, vagal activity)

• Mortality (4x) • Coronary artery disease

Heart rate variability (HRV) (Stress response, vagal activity)

• PTSD • Depression • Anxiety • Sudden death after heart attack

Heart rhythm abnormality e.g. atrial fibrillation (AF)

• Mortality (1.5x men, 1.9x women) • Stroke (5x)

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0 200 400 600 800 1000 1200 1400

MovementvsRestingHeartRate

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StandingvsRestingHeartRate

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ExercisevsRestingHeartRate

Rest

ing

Hea

rt Ra

te (b

eats

per

min

ute)

Exercise (minutes per day) Stand (hours per day) Move (calories per day)

Exercise vs Resting Heart Rate Standing vs Resting Heart Rate Movement vs Resting Heart Rate

Do Apple Watch’s activity rings drive cardiovascular improvements?

Can we use artificial intelligence to design novel biomarkers?

Semi-Supervised Sequence Learning for Continuous Digital Biomarkers

5 12 5 28 30 30dtheart rate

steps

86 0 74 0 85 83

0 5 0 97 0 0

5

83

0

…

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1 0 0 -1 1atrial fibrillation hypertensionsleep apnea

0 0 -1 0 0 1

0 0 1 0 0 -1

-1

0

0

…

…

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Multi-channel, multi-timescale

sensor input

Multi-task Output0

time ▶

Recurrent Neural Network

Fully connected tanh

Long Short-Term Memory

1D Convolution

Fully connected ReLu

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…

AF Not-AF

86 79 74 82 85 83 74Raw Heart Rate Measurements

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Clinical Gold Standard

Continuous Digital Biomarkers Applying deep learning to health

Atrial Fibrillation Normal Heart Rhythm

Accuracy on Cardioversions

True

Pos

itive

Rat

e

0

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0.9

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False Positive Rate

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

What else can you detect?

Why does this matter?

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Thanks! brandon@cardiogr.am