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Rheoencephalography: A non-invasive method for neuromonitoring Cover

Rheoencephalography: A non-invasive method for neuromonitoring

Journal of Electrical Bioimpedance
Volume 15 (2024): Issue 1 (January 2024)
By: Sandor Szabo,  Zsolt Totka,  Jozsef Nagy-Bozsoky,  Istvan Pinter,  Mihaly Bagany and  Michael Bodo  
Open Access
|Mar 2024

Figures & Tables

Fig. 1:

Trace of REG signal with Silverlon electrodes with Cerberus amplifier. The time window is 33.125 sec. The Y axis is in volt; the X axis is in second.
Trace of REG signal with Silverlon electrodes with Cerberus amplifier. The time window is 33.125 sec. The Y axis is in volt; the X axis is in second.

Fig. 2:

Boxplot of bioimpedance pulse peak values in Silverlon and Velcro electrodes (n=14 peaks). The difference is significant (p =0.0052).
Boxplot of bioimpedance pulse peak values in Silverlon and Velcro electrodes (n=14 peaks). The difference is significant (p =0.0052).

Fig. 3:

Upper two traces: 10 Hz sinus ±1 V labeled as head and arm, imitating REG, and arm bioimpedance pulses. Channels are in phase on the left and right sides; in the middle, the head pulses were inverted indicated by minimal amplitude increase—lower trace: Pearson’s correlation coefficient calculation (PRx). The left side indicates passive CBF AR, value is +1. The first PRx number is 300 sec. During the phase inversion, the value changes to −1, indicating active CBF AR status.
Upper two traces: 10 Hz sinus ±1 V labeled as head and arm, imitating REG, and arm bioimpedance pulses. Channels are in phase on the left and right sides; in the middle, the head pulses were inverted indicated by minimal amplitude increase—lower trace: Pearson’s correlation coefficient calculation (PRx). The left side indicates passive CBF AR, value is +1. The first PRx number is 300 sec. During the phase inversion, the value changes to −1, indicating active CBF AR status.

Fig. 4:

The two 10 Hz sinus ±1 V waves imitating head and arm pulse waves. On the left side in phase. On the right side is the inverted portion. The phase inversion starts at 988.35 seconds - time window: 0.965 min.
The two 10 Hz sinus ±1 V waves imitating head and arm pulse waves. On the left side in phase. On the right side is the inverted portion. The phase inversion starts at 988.35 seconds - time window: 0.965 min.

Fig. 5:

Trace of bifrontal REG (upper trace) on a tilting table. BH indicates the breath holdings. Under its label are the blood pressure (systolic/diastolic) numbers. The middle traces are the REGx traces. The lower trace shows fragments of REG during breath-holding (left side) and transition from horizontal to HDT position (right side). Arrows indicate the location of magnified portions. The Y-axis is in Volt. The X-axis is in seconds. The window size is 2630 seconds, 43.83 min. The file name is April 26 1.
Trace of bifrontal REG (upper trace) on a tilting table. BH indicates the breath holdings. Under its label are the blood pressure (systolic/diastolic) numbers. The middle traces are the REGx traces. The lower trace shows fragments of REG during breath-holding (left side) and transition from horizontal to HDT position (right side). Arrows indicate the location of magnified portions. The Y-axis is in Volt. The X-axis is in seconds. The window size is 2630 seconds, 43.83 min. The file name is April 26 1.

Fig. 6:

Fragments of recording of bifrontal and bitemporal REG pulse waves during control/rest (before HDT position; 0o), on the left side) and during HDT positions (-15o) (on the right side) in four subjects. The color indicates derivation. The Y axis is in Volt. X axis is in seconds. The window size is about 3 sec. Subjects are labeled by the recording date, for example, 4.5.1: the first recording that day.
Fragments of recording of bifrontal and bitemporal REG pulse waves during control/rest (before HDT position; 0o), on the left side) and during HDT positions (-15o) (on the right side) in four subjects. The color indicates derivation. The Y axis is in Volt. X axis is in seconds. The window size is about 3 sec. Subjects are labeled by the recording date, for example, 4.5.1: the first recording that day.

Fig. 7:

Change of P2 amplitude of REG pulse waves in female (n=6; on the left) and in the male group (n=13; on the right) before (control/baseline; 0o) and during HDT position (–15o). P<0.0001 in both groups. 95% confidence interval −0.04123 to −0.02710 in the female group and −0.05796 to −0.05178 for males.
Change of P2 amplitude of REG pulse waves in female (n=6; on the left) and in the male group (n=13; on the right) before (control/baseline; 0o) and during HDT position (–15o). P<0.0001 in both groups. 95% confidence interval −0.04123 to −0.02710 in the female group and −0.05796 to −0.05178 for males.

Fig. 8:

Averages of male and female groups bifrontal REGx during rest and HDT position. The correlation coefficient is 0.49; the statistical significance is 0.03. Note the difference during HDT. During this period, the correlation coefficient is 0.21; the statistical significance is p=0.0002. REGx decreased at the start of HDT, indicating the active status of CBF AR.
Averages of male and female groups bifrontal REGx during rest and HDT position. The correlation coefficient is 0.49; the statistical significance is 0.03. Note the difference during HDT. During this period, the correlation coefficient is 0.21; the statistical significance is p=0.0002. REGx decreased at the start of HDT, indicating the active status of CBF AR.

Fig. 9:

Comparison of cerebrovascular reactivity measured by 3 methods for 30 seconds breath-holding (BH), hyperventilation (HV), and CO2 inhalation (n=10). The figure was created from study data [41].
Comparison of cerebrovascular reactivity measured by 3 methods for 30 seconds breath-holding (BH), hyperventilation (HV), and CO2 inhalation (n=10). The figure was created from study data [41].

REG P1 and P2 amplitudes (means of 5-10 pulse peak values) during control and HDT in four subjects, calculated from pulse waves presented in Fig_ 6_ The amplitude difference was calculated as a percentage of the control/baseline (BL%)_ REGx R2: correlation coefficient of bifrontal and bitemporal REGx during the full time of the recording_ The sample traces are presented in Fig_6_ Arm bioimpedance recordings were missing in the case of the 4_5_1 subject, consequently, there was no REGx calculation_

REG peak values and REGx correlation coefficients
P1P2P1P2REGx
April 5.1R2
Control0.430.350.470.37N/A
HDT0.420.590.470.58
BL%−0.3336.3226.2757.97
April 11
Control0.710.580.70.570.75
HDT0.710.630.70.63
BL%−0.167.640.18.99
April 19.2
Control0.770.670.730.670.65
HDT0.730.730.70.67
BL%−4.748.91−4.10.71
April 21.1
Control0.810.660.810.670.55
HDT0.780.740.760.77
BL%−2.8912.01−5.7816.04
DOI: https://doi.org/10.2478/joeb-2024-0003 | Journal eISSN: 1891-5469
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Language: English
Page range: 10 - 25
Submitted on: Dec 7, 2023
Published on: Mar 13, 2024
Published by: University of Oslo
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
Keywords:
Intracranial pressure,
pulse wave morphology,
rheoencephalography,
cerebral blood flow,
autoregulation,
breath-holding,
head-down-tilt position,
noninvasive
Related subjects:
Engineering,
Bioengineering and biomedical engineering,
Biomedical electronics,
Life sciences,
Biophysics,
Medicine,
Biomedical engineering,
Physics,
Spectroscopy and metrology

© 2024 Sandor Szabo, Zsolt Totka, Jozsef Nagy-Bozsoky, Istvan Pinter, Mihaly Bagany, Michael Bodo, published by University of Oslo
This work is licensed under the Creative Commons Attribution 4.0 License.

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