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Diabetic foot assessment using skin impedance in a custom made sensor-sock

Christian Tronstad
Christian Tronstad
, 
Maryam Amini
Maryam Amini
, 
Eline Olesen
Eline Olesen
, 
Elisabeth Qvigstad
Elisabeth Qvigstad
, 
Oliver Pabst
Oliver Pabst
, 
Tormod Martinsen
Tormod Martinsen
, 
Sisay M. Abie
Sisay M. Abie
, 
Ørjan G. Martinsen
Ørjan G. Martinsen
, 
Jonny Hisdal
Jonny Hisdal
, 
Trond G. Jenssen
Trond G. Jenssen
 and 
Håvard Kalvøy
Håvard Kalvøy
   | Jan 14, 2023
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Published Online: Jan 14, 2023
Page range: 136 - 142
Received: Dec 07, 2022
DOI: https://doi.org/10.2478/joeb-2022-0019
Keywords
© 2022 Christian Tronstad, Maryam Amini, Eline Olesen, Elisabeth Qvigstad , Oliver Pabst, Tormod Martinsen, Sisay M. Abie, Ørjan G. Martinsen, Jonny Hisdal, Trond G. Jenssen, Håvard Kalvøy, published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1

Screenshot from Eagle CAD design showing the electrode geometry (each grid unit is 1mm).
Screenshot from Eagle CAD design showing the electrode geometry (each grid unit is 1mm).

Figure 2

Axisymmetric 2D distribution of simulated volume impedance density below the electrode for low (a) and high (b) frequency impedance measurement. The color gradient indicates the volume impedance density, presented on a logarithmic scale.
Axisymmetric 2D distribution of simulated volume impedance density below the electrode for low (a) and high (b) frequency impedance measurement. The color gradient indicates the volume impedance density, presented on a logarithmic scale.

Figure 3

CAD design of sensor parts for skin impedance measurement at the big toe (A), toeball (B) and heel (C). The 3D printed parts for sensor housing are shown in D, and all parts connected to the foot are shown in E.
CAD design of sensor parts for skin impedance measurement at the big toe (A), toeball (B) and heel (C). The 3D printed parts for sensor housing are shown in D, and all parts connected to the foot are shown in E.

Figure 4

An example measurement of change in measured skin impedance over 30 minutes using the electrode probe at the big toe pulp of a healthy subject. These measurements were done with the Solartron 1260+1294.
An example measurement of change in measured skin impedance over 30 minutes using the electrode probe at the big toe pulp of a healthy subject. These measurements were done with the Solartron 1260+1294.

Figure 5

Impedance spectra presented as the impedance modulus (|Z|), resistance (R) and reactance (X) for all participants from the control (black) and DPN group (blue). The bumpy curves with the highest impedance in the toeball and heel plots curves are affected by measurement error due to the high impedance levels and do not represent a true frequency-dependency of the skin impedance.
Impedance spectra presented as the impedance modulus (|Z|), resistance (R) and reactance (X) for all participants from the control (black) and DPN group (blue). The bumpy curves with the highest impedance in the toeball and heel plots curves are affected by measurement error due to the high impedance levels and do not represent a true frequency-dependency of the skin impedance.

Figure 6

Comparison of the repeatability of all measurements (control and DPN groups combined) between the different skin sites presented in a boxplot with group means added in grey dots. White dots represent outliers and edges of the whiskers represent the minimum and maximum non-outlier values within the groups. Repeatability was calculated using the log10-transformed impedance modulus at 10 Hz, taking the standard deviation of the successive measurements divided by the mean.
Comparison of the repeatability of all measurements (control and DPN groups combined) between the different skin sites presented in a boxplot with group means added in grey dots. White dots represent outliers and edges of the whiskers represent the minimum and maximum non-outlier values within the groups. Repeatability was calculated using the log10-transformed impedance modulus at 10 Hz, taking the standard deviation of the successive measurements divided by the mean.
eISSN:
1891-5469
Language:
English
Publication timeframe:
Volume Open
Journal Subjects:
Engineering, Bioengineering and Biomedical Engineering, Biomedical Electronics, Life Sciences, Biophysics, Medicine, Biomedical Engineering, Physics, Spectroscopy and Metrology
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