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Simultaneous recording of temperature and action potentials in human voluntary muscle
Electroencephalography and Clinical Neurophysiology Elsevier Publishing C o m p a n y , A m s t e r d a m - Printed in The Netherlands
CLINICAL
561
NOTE
S I M U L T A N E O U S R E C O R D I N G OF TEMPERATURE A N D ACTION
POTENTIALS IN H U M A N V O L U N T A R Y MUSCLE W . [SSEL, F . L.~HODA AND A . ROSS
Neurologische Klinik der Universitdt Miinchen, Nussbaumstr. 7, 8 Miinchen 2 (W. Germany) (Accepted for publication : November 17, 1971 )
Studying the biological activity of human voluntary muscle under physiological and pathological conditions it may be useful to measure the production of heat and the electromyographic activity simultaneously. As far as we know simultaneous measurements of temperature and action potentials at the same point within the muscle have not been carried out previously. A special needle has been designed by DISA 1 following our ideas. It is a concentric needle electrode with a temperature sensor, which permits simultaneous measurement of temperature and muscle activity (Fig. l). The needle length is 36 mm, the diameter 0.6 mm and the area of exposed platinum surface is 0.07 mm:. This needle is connected with a Biological Temperature Unit as well as with a 2-channel electromyograph (EMG). A mechanical writing system (Varioscript ~) was used for recording both the temperature and the EMG. Using this technique we investigated 25 healthy persons of different ages and both sexes. The rectal temperature was between 36.9 and 37.2°C. The temperature of the room was kept constantly at 22°C, the humidity at 60 ~ . We examined mainly mm. quadriceps femoris and biceps humeri. After pushing the needle about half its length into the muscle, avoiding the motorpoint and end-plate zone, we measured at rest, under maximal voluntary effort and just after contraction at rest again. We found in all subjects that the temperature went down shortly after starting the contraction and went down even further under maximal voluntary effort, within a range of 35.2 and 35.9°C. Therrnocouple
Connected with the Temperature Unit DISA 14 G 05
Connected w i t h ELectromyograph
Fig. 1. Diagram of the DISA electrode type 13 L 10. Dimensions in millimetres.
Fig. 2. Simultaneous record of temperature and action potentials in a normal human voluntary muscle (m. quadriceps femoris)during maximal contraction.
Fig. 3. Simultaneous record of temperature and action potentials in Erb's muscular dystrophy (m. quadriceps femoris) during maximal contraction. After finishing the contraction the temperature rose again slowly. An increase of temperature during voluntary effort was never seen. An error of the position of the needle, such as pushing it into a vessel or into fatty tissue, could be excluded by the control of simultaneous recording of the EMG. During compression of the arterial circulation in the limb we also found a decrease of temperature. The fall of temperature was even more striking in some cases of muscular dystrophy (Erb) and some cases of endarteritis obliterans. These relations are shown in Fig. 2 and 3. DISCUSSION
i DISA Elektronik A/S, Herlev, Denmark. 2 Lent by Gruber Ltd., Munich.
These investigations show that the temperature within
Electroenceph. clin. Neurophysiol., 1972, 32:561-562
w . ISSEL et al.
562 human muscle decreases under voluntary effort. This is probably due to an unknown economical principle of the muscle during contraction. Sources of error such as a change of electrode position during contraction or a falling temperature gradient toward the skin surface can be excluded by exact measurement of the exposed length of the needle and the particular construction of the electrode. An effect on the thermoelement by a change of the bioelectrical surroundings during contraction can also be excluded, because the thermoelement did not show any change in temperature while the system was checked in physiological NaC1 solution under 4.5 V d.c. This observation disagrees with the previous investigations by Fick (1882), Hill (1938), Reichel (1960), Wilkie (1960) and others. The explanation is probably that it was impossible until now, for technical reasons, to fit such a microthermocouple into the tip of a concentric needle electrode of normal diameter. This construction makes it possible for the first time to record EMG and temperature at the same point in the muscle simultaneously. This is a fundamental difference from previous measurements by thermistors, which may have recorded bioelectrical changes during contraction of striated muscle as a fictitious increase of temperature. Thermistors or similar devices were used by Hill (1938), Reichel (1960) and Wilkie (1960). Further experiments concerning different aspects under normal and pathological conditions may detect more information about the thermodynamic changes in human muscle.
SUMMARY Simultaneous recording of the action potentials and the temperature in human voluntary muscle were carried out with a special concentric needle containing a microthermocouple. It was shown that the temperature decreased under voluntary contraction of the muscle. An increase was never seen, as opposed to previous investigations in which thermistors were used. ZUSAMMENFASSUNG TEMPERATUR IM MUSKEL Mit einer speziellen konzentrischen Nadelelektrode wurden simultane Messungen von Aktionspotentialen ,~r~" Temperatur im menschlichen Skelettmuskel durchgef'tihrt. Es wurde gezeigt, dass die Temperatur unter willkiirlicher Kontraktion des Muskels absinkt. Ein Ansteigen wurde nicht beobachtet. Die Versuchsanordnung wird beschrieben. REFERENCES FICK, A. Mechanisehe Arbeit und Wdrrneentwieklun 9 bei der Muskeltiitigkeit. Brockhaus, XIII: 239 p. In Intern. Wiss. Bibl., Vol. 51. Leipzig, 1882. HILL, A. V. The heat of shortening and the dynamic constants of muscle. Proc. roy. Soc. B, 1938, 126: 136-195. RE1CHEL, H. Muskelphysiolooie. Springer, Berlin, 1960, 276 p. WILKIE, D. R. Thermodynamics and the interpretation of biological heat measurements. Progr. Biophys., 1960, I0: 259-298.
Reference: ISSEL, W., L.~HODA, F. and Ross, A. Simultaneous recording of temperature and action potentials in human voluntary muscle. Electroenceph. clin. Neurophysiol., 1972, 32: 561-562.
CLINICAL
561
NOTE
S I M U L T A N E O U S R E C O R D I N G OF TEMPERATURE A N D ACTION
POTENTIALS IN H U M A N V O L U N T A R Y MUSCLE W . [SSEL, F . L.~HODA AND A . ROSS
Neurologische Klinik der Universitdt Miinchen, Nussbaumstr. 7, 8 Miinchen 2 (W. Germany) (Accepted for publication : November 17, 1971 )
Studying the biological activity of human voluntary muscle under physiological and pathological conditions it may be useful to measure the production of heat and the electromyographic activity simultaneously. As far as we know simultaneous measurements of temperature and action potentials at the same point within the muscle have not been carried out previously. A special needle has been designed by DISA 1 following our ideas. It is a concentric needle electrode with a temperature sensor, which permits simultaneous measurement of temperature and muscle activity (Fig. l). The needle length is 36 mm, the diameter 0.6 mm and the area of exposed platinum surface is 0.07 mm:. This needle is connected with a Biological Temperature Unit as well as with a 2-channel electromyograph (EMG). A mechanical writing system (Varioscript ~) was used for recording both the temperature and the EMG. Using this technique we investigated 25 healthy persons of different ages and both sexes. The rectal temperature was between 36.9 and 37.2°C. The temperature of the room was kept constantly at 22°C, the humidity at 60 ~ . We examined mainly mm. quadriceps femoris and biceps humeri. After pushing the needle about half its length into the muscle, avoiding the motorpoint and end-plate zone, we measured at rest, under maximal voluntary effort and just after contraction at rest again. We found in all subjects that the temperature went down shortly after starting the contraction and went down even further under maximal voluntary effort, within a range of 35.2 and 35.9°C. Therrnocouple
Connected with the Temperature Unit DISA 14 G 05
Connected w i t h ELectromyograph
Fig. 1. Diagram of the DISA electrode type 13 L 10. Dimensions in millimetres.
Fig. 2. Simultaneous record of temperature and action potentials in a normal human voluntary muscle (m. quadriceps femoris)during maximal contraction.
Fig. 3. Simultaneous record of temperature and action potentials in Erb's muscular dystrophy (m. quadriceps femoris) during maximal contraction. After finishing the contraction the temperature rose again slowly. An increase of temperature during voluntary effort was never seen. An error of the position of the needle, such as pushing it into a vessel or into fatty tissue, could be excluded by the control of simultaneous recording of the EMG. During compression of the arterial circulation in the limb we also found a decrease of temperature. The fall of temperature was even more striking in some cases of muscular dystrophy (Erb) and some cases of endarteritis obliterans. These relations are shown in Fig. 2 and 3. DISCUSSION
i DISA Elektronik A/S, Herlev, Denmark. 2 Lent by Gruber Ltd., Munich.
These investigations show that the temperature within
Electroenceph. clin. Neurophysiol., 1972, 32:561-562
w . ISSEL et al.
562 human muscle decreases under voluntary effort. This is probably due to an unknown economical principle of the muscle during contraction. Sources of error such as a change of electrode position during contraction or a falling temperature gradient toward the skin surface can be excluded by exact measurement of the exposed length of the needle and the particular construction of the electrode. An effect on the thermoelement by a change of the bioelectrical surroundings during contraction can also be excluded, because the thermoelement did not show any change in temperature while the system was checked in physiological NaC1 solution under 4.5 V d.c. This observation disagrees with the previous investigations by Fick (1882), Hill (1938), Reichel (1960), Wilkie (1960) and others. The explanation is probably that it was impossible until now, for technical reasons, to fit such a microthermocouple into the tip of a concentric needle electrode of normal diameter. This construction makes it possible for the first time to record EMG and temperature at the same point in the muscle simultaneously. This is a fundamental difference from previous measurements by thermistors, which may have recorded bioelectrical changes during contraction of striated muscle as a fictitious increase of temperature. Thermistors or similar devices were used by Hill (1938), Reichel (1960) and Wilkie (1960). Further experiments concerning different aspects under normal and pathological conditions may detect more information about the thermodynamic changes in human muscle.
SUMMARY Simultaneous recording of the action potentials and the temperature in human voluntary muscle were carried out with a special concentric needle containing a microthermocouple. It was shown that the temperature decreased under voluntary contraction of the muscle. An increase was never seen, as opposed to previous investigations in which thermistors were used. ZUSAMMENFASSUNG TEMPERATUR IM MUSKEL Mit einer speziellen konzentrischen Nadelelektrode wurden simultane Messungen von Aktionspotentialen ,~r~" Temperatur im menschlichen Skelettmuskel durchgef'tihrt. Es wurde gezeigt, dass die Temperatur unter willkiirlicher Kontraktion des Muskels absinkt. Ein Ansteigen wurde nicht beobachtet. Die Versuchsanordnung wird beschrieben. REFERENCES FICK, A. Mechanisehe Arbeit und Wdrrneentwieklun 9 bei der Muskeltiitigkeit. Brockhaus, XIII: 239 p. In Intern. Wiss. Bibl., Vol. 51. Leipzig, 1882. HILL, A. V. The heat of shortening and the dynamic constants of muscle. Proc. roy. Soc. B, 1938, 126: 136-195. RE1CHEL, H. Muskelphysiolooie. Springer, Berlin, 1960, 276 p. WILKIE, D. R. Thermodynamics and the interpretation of biological heat measurements. Progr. Biophys., 1960, I0: 259-298.
Reference: ISSEL, W., L.~HODA, F. and Ross, A. Simultaneous recording of temperature and action potentials in human voluntary muscle. Electroenceph. clin. Neurophysiol., 1972, 32: 561-562.