Abstract

The literature is sparse and equivocal on possible influence of hyperbaric exposure on postural control and the vestibular system. The hypothesis of this research was to show that deep heliox diving influences postural control and the vestibular system. Multiple objective measurements of postural control were made in four divers by means of a static balance platform before, during and after an onshore experimental saturation heliox chamber dive of 32 days duration. Saturation pressure was 4.6 MPa, corresponding to a depth of 450 meters of seawater (msw). Downward excursions down to 470 msw were also performed. Clinical ENT and otoneurological examination, including bithermal caloric vestibular testing with electronystagmography (ENG) was performed before and after the dive. Reduced postural control was detected by the balance platform test in all four divers from approximately 200 msw and deeper. Body sway showed a distinct increase during compression, reaching a maximum value during the bottom phase. The Romberg index was not suitable for describing shifts in postural stability. All sway parameters returned to pre-dive values after surfacing. Immediately post-dive, most caloric responses were reduced, compared to the pre-dive results. We conclude that deep heliox diving seems to influence postural control and the vestibular system. Computerized stabilometry is one convenient and sensitive method of monitoring postural control during saturation diving. The path length of the center of pressure (COP) seems to be suitable as a monitoring parameter.