Electronystagmography and saturation deep diving at 4.6 MPa

In the course of the ENTEX V and VIII saturation deep diving experiments at 4.6 MPa for 12 d, electronystagmography monitoring was performed on divers before, during, and after the stay in the diving chamber. In a vestibular sense, these dives were well-tolerated subjectively, clinically, and infraclinically by the divers. However, a decrease in the nystagmus induced by caloric stimulation was seen in 4 out of 8 divers during the confinement period at 0.2 MPa and in 6 out of 8 divers upon reaching 4.6 MPa, followed by variable responses dependent on the subject, with total recovery on reaching the surface. These results are explained on one hand in terms of the thermal conductivity of helium, and on the other in terms of a rough form of HPNS.