Changes of sensory conduction velocity and refractory periods with decreasing tissue temperature in man

Abstract

Changes with temperature of maximum sensory nerve conduction velocity as well as absolute and relative refractory periods were tested in 14 human subjects. Corresponding to previously published findings maximum conduction velocity decreased with cooling following a Q10 of +1.4. The absolute and relative refractory periods were increased by cooling, the Q10 being -3.1 and -3.35 respectively. There was a tendency showing a more pronounced temperature effect at low temperatures. The Q10 and the steepness of the regressionline changed at the level of 26.9 degrees C, but were significant for the relative refractory period only.

Temperature dependence of excitability indices of human cutaneous afferents

“…The latency data confirm existing knowledge, 12,24,31 but the threshold and strengthduration data are new. The effect of cooling on refractoriness was much greater than on other measures of axonal function, whether assessed using FIGURE 4.…”

“…The increase in refractoriness with decrease in skin temperature was greater the lower the temperature (Fig. 3), a finding also noted in latency measurements by Lowitzsch et al 24 Accordingly, refractoriness increased by 88.7 ± 31.0% of the control value over the 4°C to 27°C and by a further 297.3 ± 89.2% over the 4°C below 27°C for the 5 subjects in whom the 2-ms threshold could be followed below 27°C.…”

“…Clinically, the best documented changes with cooling within the physiological range are slowing of impulse conduction and an increase in refractoriness 4,12,23,24,31 and, in demyelinated axons, improvement in the safety margin for impulse conduction. 34,37,41,44 In critically demyelinated axons, small increases in temperature, such as those that occur with exercise, ovulation, fever, and the normal circadian variation, can precipitate conduction failure, 34 a phenomenon well documented in multiple sclerosis.…”

Modelled temperature-dependent excitability behaviour of a single ranvier node for a human peripheral sensory nerve fibre

“…Studies on human peripheral nerve fibres indicate an increase in action potential amplitude and duration, the absolute and relative refractory periods and chronaxie times when the temperature is decreased from 37 • C; while the rheobase current and conduction velocity decrease under the same temperature conditions (Buchthal and Rosenfalck 1966;Lowitzsch et al 1977;Kiernan et al 2001). Temperature dependence of the sodium channel kinetics is included in computational models describing excitation behaviour in human nerve fibres; for example the models of Schwarz et al (1995) and Wesselink et al (1999), but not so for the potassium channel and leakage kinetics, as well as other electrical parameters used.…”

Changes of Compound Muscle Action Potential after Low-Intensity Exercise with Transient Restriction of Blood Flow: a Randomized, Placebo-Controlled Trial

“…Therefore, a temperature increase in the APB region may be experienced. When the temperature of a nerve increases from 29 °C to 38 °C, nerve conduction velocity increases by approximately 5% per a 1 °C rise in temperature 23) . The amplitude of nerve and muscle action potentials is thereby reduced 24) .…”