Key result
Normalized pulse volume derived from the bottom of the ear-canal significantly decreased during cold water immersion and correlated with index finger measurements, validating it as a measure of sympathetic activity.
Why the study?
Is normalized pulse volume derived from the outer ear using reflection photoplethysmography a valid measure of sympathetic activity compared to index finger transmission photoplethysmography?
Population
16 subjects (10 young and 6 middle-aged)
Comparison
Measurement of normalized pulse volume from the… vs Measurement of NPV from the index finger using…
Authors
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Ear-canal normalized pulse volume may index sympathetic activity; leaves open validation in patients and clinical settings.
Observational (n=16)
No
Is normalized pulse volume derived from the outer ear using reflection photoplethysmography a valid measure of sympathetic activity compared to index finger transmission photoplethysmography?
Absolute Event Rate: -8.27% vs -8.01%
p-value: p=<0.001
Normalized pulse volume derived from the bottom of the ear-canal using reflection photoplethysmography is a valid measure of sympathetic activity, comparable to finger transmission photoplethysmography.
Lee et al. (2013) conducted an observational in Healthy volunteers (n=16). Cold pressor test (CPT) and warm water immersion (WWI) vs. Baseline resting state was evaluated on Normalized pulse volume (lnNPV) at the bottom of the ear-canal during cold pressor test in young subjects (p=<0.001). Normalized pulse volume derived from the bottom of the ear-canal significantly decreased during cold water immersion and correlated with index finger measurements, validating it as a measure of sympathetic activity.
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