Experimental neuro-otological investigations under hyperbaric impacts

The authors generalize the results of 20-years investigations on 79 divers in a subwater home at real subwater work and in a barochamber from 8.5 to 46 ATA in air and helium-oxygen-nitrogen breathing environment (three-mix) and from experiments with animals at 11 ATA in a barochamber and blast decompression. Complex medico-biological investigations were performed over this period. The results show increased individual audiometric threshold with 35-40 dB, hearing loss, proportional to the increase of the pressure. The hyperbaric factors impact on the auditory-vestibular analyzer, the changes in the middle ear and barotraumas prevailing at smaller depths. All levels of the hearing system are affected in air environment, but the most marked changes are those in the cortex end of the hearing analyzer. In three-mix, there are serious disturbances in the communication due to the so called ''helium speech'', violated motion coordination and overcooling of the body. The professional selection and periodical medical examinations with complex medicobiological investigations are necessary for the prevention of health risk and prophylactics, related to the workers in hyperbaric conditions.