1. ›
Monitoring the cardiac interval from iOS
›
James A.J. Heathers
Psychophysiology Lab, University of Sydney
Insert
Partner L
- Delete if not requ

2. WHAT IS HRV?

3. SOLUTIONS TO HRV DRAWBACKS
Increase experimental power in between-subjects research
by an order of magnitude.
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Develop a system which allows parallel data collection, rather than
serial data collection.
By necessity, system must be accurate, robust, and cheap enough to
have several duplicates.
System must be run by user, i.e. under diminished experimenter
control, so interface and tasks must be user-friendly.

4. THE NEW SYSTEM
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iOS device (iPod, iPad etc.)
Hardware filter
Optical sensor
Eventual setup:
1. Wi-Fi is connected (if not 3G)
2. Participant downloads application from
iTunes store
3. System is connected and automatically
achieves stable baseline
4. Data is collected through app interface
5. Data is sent through phone mail client to
inbox e.g. prv_study@gmail.com
6. Data is downloaded, coded, and email
account is deleted – which de-identifies
data completely

5. THE EXPERIMENTS
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Study 1: Provisionally implement the described system
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Compare reliability to:
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a) traditional laboratory ECG
b) other dedicated optical psychophysiological system
Study 2: Replicate a broad series of important between-subjects results
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n=105 at baseline
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Data taken in class, over four days
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Data taken a) at baseline, b) during paced breathing, c) during exposure to
positive/negative image sets.

6. THE EXPERIMENTS
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Study 3: Test normal postural positions for equivalence
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Compare reliability to traditional laboratory ECG between postures
Lying
Standing
Sitting
Tilt (at 30° to horizontal)
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Study 4: Mass HR collection in development economics sample
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Pilot of n=80-250, then main sample of n=2500-3000
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Data taken in Mekelle, Ethiopia as an adjunct to a food aid program

7. THE CONCLUSION
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Works
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Roughly equivalent to lab system, median margin of error about 3%
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6x cheaper than Polar or sports/portable system
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50x cheaper than lab equipment
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Further possibilities for pulse signal beyond simple HR monitoring
Further details:
iPhone app:
Once developed, not open-source but free. In dev.
Hardware:
Pre-market, but most likely for sale (for not much!) soon.
Thank you!