Healthc Inform Res.  2015 Jan;21(1):30-34. 10.4258/hir.2015.21.1.30.

Aging Index using Photoplethysmography for a Healthcare Device: Comparison with Brachial-Ankle Pulse Wave Velocity

• Hong KS
• Park KT
• Ahn JM

• KMID: 2284595
• DOI: http://doi.org/10.4258/hir.2015.21.1.30

Abstract

OBJECTIVES
Recent studies have emphasized the potential information embedded in peripheral fingertip photoplethysmogram (PPG) signals for the assessment of arterial wall stiffening during aging. For the discrimination of arterial stiffness with age, the brachial-ankle pulse wave velocity (baPWV) has been widely used in clinical applications. The second derivative of the PPG (acceleration photoplethysmogram [APG]) has been reported to correlate with the presence of atherosclerotic disorders. In this study, we investigated the association among age, the baPWV, and the APG and found a new aging index reflecting arterial stiffness for a healthcare device.
METHODS
The APG and the baPWV were simultaneously applied to assess the accuracy of the APG in measuring arterial stiffness in association with age. A preamplifier and motion artifact removal algorithm were newly developed to obtain a high quality PPG signal. In total, 168 subjects with a mean +/- SD age of 58.1 +/- 12.6 years were followed for two months to obtain a set of complete data using baPWV and APG analysis.
RESULTS
The baPWV and the B ratio of the APG indices were correlated significantly with age (r = 0.6685, p < 0.0001 and r = -0.4025, p < 0.0001, respectively). A regression analysis revealed that the c and d peaks were independent of age (r = -0.3553, p < 0.0001 and r = -0.3191, p < 0.0001, respectively).
CONCLUSIONS
We determined the B ratio, which represents an improved aging index and suggest that the APG may provide qualitatively similar information for arterial stiffness.

Keyword

Photoplethysmography; Acceleration Plethysmogram; Arterial Stiffness; Pulse Wave Velocity; Motion Artifact

MeSH Terms

Aging*
Artifacts
Delivery of Health Care*
Discrimination (Psychology)
Photoplethysmography*
Pulse Wave Analysis*
Vascular Stiffness

Figure

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  Figure 1 (Top) Original fingertip photoplethysmogram waveform. (Bottom) Second derivative of the photoplethysmogram (i.e., acceleration photoplethysmogram).

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  Figure 2 System configuration using microcontroller. 2nd LPF: second low-pass filter, HPF: high-pass filter, 60 Hz IIR notch filter: removal of 60 Hz power line with infinite impulse response, BPF FIR filter: band-pass filter finite impulse response filter, Ave filter: averaging filter, 1st, 2nd, 3rd, and 4th derivative: the order of the derivative of the photoplethysmogram waveform.

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  Figure 3 Scatter diagrams of the relationship between the brachial-ankle pulse wave velocity (baPWV) and age (A) and the relationship between the B ratio of the acceleration photoplethysmogram and age (B).

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