Effects of hyperbaric environment on human auditory middle latency response (MLR) and short latency somatosensory evoked potential (SSEP).
Hyperbaric chamber dives at 19 ATA with helium-oxygen were performed at the Japan Marine Science Technology Center from November 15 to December 3 in 1988 and from January 25 to February 4 in 1989. During simulated underwater experiments, auditory middle latency responses (MLRs) and short latency somatosensory evoked potentials (SSEPs) were recorded in 3 professional divers (2 divers in each dive) for assessment of brain function. During the saturation dive (180 m below sea level) component Pa on MLR was lost, while component Po remarkably increased in amplitude. These MLR changes rapidly recovered between the beginning of decompression and at about 90 m below sea level. On the other hand, N9-N20 interpeak latency on SSEP slightly or moderately increased in the both divers, but N9-N14 interpeak latency was not affected by the 19 ATA saturation dive. These results suggest that the hyperbaric environment corresponding to 180 m below sea level cause some cerebral dysfunctions, probably between the brainstem and the cortex, but these dysfunctions are only transient.
Wada
S
S
Department of Neurosurgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Yokota
A
A
Matsuoka
S
S
Kadoya
C
C
Mohri
M
M
D000328:Adult; D001921:Brain / Q000502:physiology; D004242:Diving; D005072:Evoked Potentials, Auditory; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D006874:Hydrostatic Pressure / Q000009:adverse effects*; D008297:Male; D011312:Pressure / Q000009:adverse effects*; D011930:Reaction Time / Q000502:physiology*