High-pressure nervous syndrome

High-pressure nervous syndrome (HPNS – also known as high-pressure neurological syndrome) is a neurological and physiological diving disorder which can result when a diver descends below about 500 feet (150 m) using a breathing gas containing helium. The effects experienced, and the severity of those effects, depend on the rate of descent, the depth and the percentage of helium.^[1]

"Helium tremors" were described in 1965 by Royal Navy physiologist Peter B. Bennett.^[1]^[2] Soviet scientist G. L. Zal'tsman first reported on helium tremors in his experiments from 1961. These reports were not available in the West until 1967.^[3]

The term high-pressure nervous syndrome was first used by R. W. Brauer in 1968 to describe the combined symptoms of tremor, electroencephalography (EEG) changes, and somnolence that appeared during a 1,189-foot (362 m) chamber dive in Marseille.^[4]

^ ^a ^b Bennett, Peter B; Rostain, Jean Claude (2003). "The High Pressure Nervous Syndrome". In Brubakk, Alf O.; Neuman, Tom S (eds.). Bennett and Elliott's physiology and medicine of diving, 5th Rev ed. United States: Saunders. pp. 323–57. ISBN 0-7020-2571-2.
^ Bennett, P. B. (1965). "Psychometric impairment in men breathing oxygen-helium at increased pressures". Royal Navy Personnel Research Committee, Underwater Physiology Subcommittee Report No. 251. London.
^ Zal'tsman, G. L. (1967). "Psychological principles of a sojourn of a human in conditions of raised pressure of the gaseous medium (in Russian, 1961)". English Translation, Foreign Technology Division. AD655 360. Wright Patterson Air Force Base, Ohio.
^ Brauer, R. W. (1968). "Seeking man's depth level". Ocean Industry. 3. London: 28–33.

[Brubakk-1] Bennett, Peter B; Rostain, Jean Claude (2003). "The High Pressure Nervous Syndrome". In Brubakk, Alf O.; Neuman, Tom S (eds.). Bennett and Elliott's physiology and medicine of diving, 5th Rev ed. United States: Saunders. pp. 323–57. ISBN 0-7020-2571-2.

[Bennett-2] Bennett, P. B. (1965). "Psychometric impairment in men breathing oxygen-helium at increased pressures". Royal Navy Personnel Research Committee, Underwater Physiology Subcommittee Report No. 251. London.

[3] Zal'tsman, G. L. (1967). "Psychological principles of a sojourn of a human in conditions of raised pressure of the gaseous medium (in Russian, 1961)". English Translation, Foreign Technology Division. AD655 360. Wright Patterson Air Force Base, Ohio.

[4] Brauer, R. W. (1968). "Seeking man's depth level". Ocean Industry. 3. London: 28–33.

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