Highlights of the Book

Jaakko Malmivuo and Robert Plonsey:
Bioelectromagnetism - Principles and Applications of
Bioelectric and Biomagnetic Fields

 

1. Introduction of the term and discipline of "Bioelectromagnetism".

2. It is emphasized that the measurement of bioelectric and biomagnetic signals, electric and magnetic stimulation, and measurement of the tissue impedance are closely connected through the Maxwell Equations and the principle of reciprocity. When one of these cases is known, for instance the distribution of measurement sensitivity, it is possible to accurately derive from that the distribution of stimulation energy or sensitivity distribution of the impedance measurement. (pp. 5, 8)

3. In the description of the history of bioelectromagnetism it is shown that until the end of last century the history of the whole electromagnetism was actually the history of bioelectromagnetism. At the same time it is shown that the observation of H.C. Örstedt in 1819 on the connection between electricity and magnetism joins the bioelectric and biomagnetic phenomena closely together. It is also shown that the biomagnetic measurements are not a new invention, since the first measurement of a bioelectric phenomenon in 1838 was made with a detector of the magnetic field induced by the bioelectric current. This was a planar gradiometer, e.g. the same coil construction which is used nowadays in the measurement of the MEG (pp. 17, 18, 25).

4. The importance of the discipline of bioelectromagnetism is emphasized with the list of Nobel Prizes given to bioelectromagnetism and closely related subjects. The list includes 16 prizes which are shared by 28 scientists, including Ragnar Granit (p. 26, Tab. 1.6).

5. The book includes important reference material created for this purpose and which cannot be found elsewhere. This includes the passive response of the membrane to electric stimulation (p. 61, Fig. 3.11), the behavior of the Hodgkin-Huxley membrane model (pp. 78-88, eg. Fig. 4.11, 4.14), illustration of the field distribution of the Helmholtz coils (pp. 241, Fig, 12.7 a, b, c, d), sensitivity distribution of EEG leads (p. 261, Fig. 13.4) and sensitivity distribution of magnetic leads (pp. 248 - 254, Figs. 12.15, 12.16, 12.17, 12.18, 12.19, 12.20).

6. The book includes the first illustrative physical model for the fundamental membrane model of Hodgkin and Huxley. Professors Alan L. Hodgkin and Andrew F. Huxley have accepted it (pp. 80 - 84, Figs. 4.13, 4.16).

7. Combining the information obtained with the patch-clamp method (Neher & Sakmann, Nobel Prize 1991) form a single ionic channel to the Hodgkin-Huxley model (pp. 95 - 102, Fig. 4.27).

8. The first comprehensive and logical presentation of the mathematical and graphical methods used in analyzing the volume sources and -conductors (Chapter 11, pp. 185 - 226).

9. Description of the similarities and differences of bioelectric and biomagnetic methods creates the basis for obtaining new information with biomagnetism (Chapter 12, pp. 230 - 235).

10. Illustration of the sensitivity distribution of EEG-leads. Demonstrating that the same figures also illustrate the energy distribution in electric stimulation (pp. 261 - 262, Fig. 13.4).

11. Illustration of the sensitivity distribution of MEG-leads (pp. 267 - 272, Figs. 14.2, 14.3, 14.4, 14.5). Demonstrating that the energy distribution in magnetic stimulation is calculted in the same way.

12. Calculation of the sensitivity distribution of magnetic stimulation (p. 378, Fig. 22.3).

13. Comparison of the measurement accuracy of the EEG- and MEG- leads and demonstrating that, unlike it is generally believed, the EEG measures the electric activity of the brain more accurately than the MEG. (p. 273, Fig. 14.6).

14. Comprehensive historical and theoretical description of the ECG systems, including the Akulynchev system from which there does not exist any other detailed illustration (p. 295, Figs. 16.6 and 16.7).

15. Description of the MCG recording systems. (pp. 341 - 351, Figs. 20.5, 20.6, 20.7, 20.10, 20.12 and 20.13).

16. Description of the only such biomagnetic clinical study where with a large enough patient material it is obtained statistically significant improvement in the diagnostic performance. By combining the ECG and MCG signals it has been possible to decrease the number of incorrectly diagnosed patients to one half when compared to that of ECG alone (p. 357, Fig. 20.23). This MCG-study was made at the Ragnar Granit Institute.

17. Detailed description of the basis of the impedance cardiographic method (p. 411, Fig. 25.6).

18. Consistent coordinate system for electro- and magnetocardiology (p. 450, Fig. A.1).