Long-term neurological sequelae after decompression sickness in retired professional divers

Decompression sickness (DCS) has traditionally been categorized as type I DCS, affecting joints and skin, and type II affecting the nervous system. In the present study, we wanted to examine whether divers with a history of neurological DCS demonstrated a pattern of symptoms and clinical neurological and neurophysiological signs different from divers with other manifestations of DCS or no history of DCS.

Up to 1990, 365 Norwegian offshore divers worked in the North Sea. Two hundred and eight divers who had performed saturation diving, bounce diving or both, were included in this study. They filled in a questionnaire for registration of diving experience and health complaints, and episodes of DCS were registered. All participants had a clinical neurological and neurophysiological examination (ERP- P300).

One hundred and sixty three of the 208 divers (78.4%) reported episodes of DCS. Neurological DCS was reported by 41 (19.7%) divers. Forty-five divers (21.6%) reported no episodes of DCS. Divers who reported episodes of DCS reported significantly more symptoms compared with divers who reported no DCS. Divers who reported neurological DCS had significantly more neurological findings on motility tests, sensory tests and coordination/cerebellar tests. The P300 motor reaction times were significantly longer in divers reporting DCS, but there was no significant difference between divers with neurological DCS and divers with other forms of DCS.

This study indicates that DCS is associated with long-term effects on the nervous system independent of the symptomatology in the acute stage.