Journal of Applied Physiology, Vol 47, Issue 4 804-812, Copyright © 1979 by American Physiological Society
Tremor and somatosensory studies during chamber He-O2 compressions to 13.1, 25.2, 37.3, and 49.4 ATA
J. Spencer, A. Findling, A. J. Bachrach, R. Gelfand, C. J. Lambertsen and G. Karreman
Comparison was made between intentional and postural tremor amplitudes with
a 2-to 50-Hz bandwidth in four men rapidly compressed from surface to 13.1,
25.2, and 37.3 ATA in 4 h while breathing helium-oxygen mixtures
(Predictive Studies IV, University of Pennsylvania). Excursions with
compression rates of 20 and 40 ft/min were then made to 49.4 ATA on
exposure days 2 and 3, returning to saturation at 37.3 ATA for 6 additional
days. During compression from 25.2 to 37.3 ATA, there were increases in
tremor amplitudes for both intentional and postural tremor in the 3-to 7-Hz
and 8- to 12-Hz ranges. Both types of tremor showed increases in amplitudes
at 49.4 ATA on exposure days 2 and 3. Amplitude changes in postural tremor,
which occurred only on the fastest compression to 49.4 ATA, were less
evident than those in intentional tremor during the remaining dive profile,
and adaptation to pressure exposure could be defined by day 8. Intentional
tremors did not show adaptation at pressure.
