[Acute and chronic effects of deep diving on the nervous system]

Diving deeper than 180 metres of seawater (msw) will impose neurological symptoms in most divers. Atactic signs and abnormal EEGs were found in five of 18 divers immediately after deep diving. Neuropsychological testing before and after deep diving in 64 divers revealed a reduction in autonomic reactivity (48%), increased hand tremor (27%) and impairment of spatial memory and reduced finger coordination (8%) after the dives. These results had not improved one year later. A follow-up study of 40 divers one to seven years after their last deep dive revealed that the divers experienced more problems of concentration and paresthesia in feet and hands than the controls. Two had had seizures, one had suffered episodes of transitory cerebral ischemia and one had experienced transitory global amnesia after the deep dives. In the future, oil installations at depths below 180 msw should be installed and maintained with remote control and robot technology.