Postural control in a simulated saturation dive to 240 msw.
Type
Journal article; Peer reviewedPeer reviewed
publishedVersion

View/ Open
Date
2007
Metadata
Show full item recordAbstract
INTRODUCTION: There is evidence that increased ambient pressure
causes an increase in postural sway. This article documents postural sway at pressures not previously studied
and discusses possible mechanisms. METHODS: Eight subjects participated in a dry chamber dive to 240
msw (2.5 MPa) saturation pressure. Two subjects were excluded due to unilateral caloric weakness before
the dive. Postural sway was measured on a force platform. The path length described by the center of
pressure while standing quietly for 60 seconds was used as test variable. Tests were repeated 38 times in four
conditions: with eyes open or closed, while standing on bare platform or on a foam rubber mat. RESULTS:
Upon reaching 240 msw, one subject reported vertigo, disequilibrium and nausea, and in all subjects, mean
postural sway increased 26% on bare platform with eyes open (p < 0.05) compared to predive values. There
was no significant improvement in postural sway during the bottom phase, but a trend was seen toward
improvement when the subjects were standing with eyes closed on foam rubber (p = 0.1). Postural sway
returned to predive values during the decompression phase. DISCUSSION: Postural imbalance during deep
diving has been explained previously as HPNS possibly including a specific effect on the vestibulo-ocular
reflex. Although vertigo and imbalance are known to be related to compression rate, this study shows that
there remains a measurable increase in postural sway throughout the bottom phase at 240 msw, which seems
to be related to absolute pressure.
Citation
Undersea and Hyperbaric Medicine 34(2): 123-130Publisher
The Undersea and Hyperbaric Medical SocietyCollections
Copyright 2007 Undersea and Hyperbaric Medical Society. With permission from the Undersea and Hyperbaric Medical Society.
The Undersea and Hyperbaric Medical Society.
The Undersea and Hyperbaric Medical Society.