Vegard Munkeby Joten

• Singstad, Bjørn Jostein; Azulay, Naomi; Bjurstedt, Andreas; Bjørndal, Simen Chill; Drageseth, Magnus Flø & Austdal, Lars Peter Engeset [Show all 21 contributors for this article] (2021). Estimation of heart rate variability from finger photoplethysmography during rest, mild exercise and mild mental stress. Journal of Electrical Bioimpedance. 12(1), p. 89–102. doi: 10.2478/joeb-2021-0012. Full text in Research Archive Show summary

  Abstract Due to the possibilities in miniaturization and wearability, photoplethysmography (PPG) has recently gained a large interest not only for heart rate measurement, but also for estimating heart rate variability, which is derived from ECG by convention. The agreement between PPG and ECG-based HRV has been assessed in several studies, but the feasibility of PPG-based HRV estimation is still largely unknown for many conditions. In this study, we assess the feasibility of HRV estimation based on finger PPG during rest, mild physical exercise and mild mental stress. In addition, we compare different variants of signal processing methods including selection of fiducial point and outlier correction. Based on five minutes synchronous recordings of PPG and ECG from 15 healthy participants during each of these three conditions, the PPG-based HRV estimation was assessed for the SDNN and RMSSD parameters, calculated based on two different fiducial points (foot point and maximum slope), with and without outlier correction. The results show that HRV estimation based on finger PPG is feasible during rest and mild mental stress, but can give large errors during mild physical exercise. A good estimation is very dependent on outlier correction and fiducial point selection, and SDNN seems to be a more robust parameter compared to RMSSD for PPG-based HRV estimation.

• Aria, Shafa; Elfarri, Yassine; Elvegård, Marius; Gottfridsson, Adam; Grønaas, Halvor & Harang, Sigve Smedsrud [Show all 25 contributors for this article] (2019). Measuring blood pulse wave velocity with bioimpedance in different age groups. Sensors. 19:850(4), p. 1–10. doi: 10.3390/s19040850. Full text in Research Archive Show summary

  In this project, we have studied the use of electrical impedance cardiography as a possible method for measuring blood pulse wave velocity, and hence be an aid in the assessment of the degree of arteriosclerosis. Using two different four-electrode setups, we measured the timing of the systolic pulse at two locations, the upper arm and the thorax, and found that the pulse wave velocity was in general higher in older volunteers and furthermore that it was also more heart rate dependent for older subjects. We attribute this to the fact that the degree of arteriosclerosis typically increases with age and that stiffening of the arterial wall will make the arteries less able to comply with increased heart rate (and corresponding blood pressure), without leading to increased pulse wave velocity. In view of these findings, we conclude that impedance cardiography seems to be well suited and practical for pulse wave velocity measurements and possibly for the assessment of the degree of arteriosclerosis. However, further studies are needed for comparison between this approach and reference methods for pulse wave velocity and assessment of arteriosclerosis before any firm conclusions can be drawn.

• Andersen, Jan-Hugo; Bjerke, Olav; Blakaj, Fatos; Flugsrud, Vilde Moe; Jacobsen, Fredrik Alstad & Jonsson, Marius [Show all 24 contributors for this article] (2019). Bioimpedance and NIR for non-invasive assessment of blood glucose. Journal of Electrical Bioimpedance. 10, p. 133–138. doi: 10.2478/joeb-2019-0019. Full text in Research Archive

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