Electroencephalography and magnetic resonance imaging after diving and decompression incidents: a controlled study

Diving incidents with symptoms of decompression sickness (DCS) and/or arter ial gas emboli (AGE) might increase the degree of pathologic change in the ef ectroencephalogram (EEG) or magnetic resonance imaging (MRI) of the supr aspinal central nervous system (CNS). Diving itself, even without known sym ptoms of DCS and/or AGE, has been proposed to increase the number of CNS le sions using either EEG or MRI. In the first part of a two-part study we exa mined the effects of recompression treatment on EEG in decompression incide nts in a group of sport and professional divers compared with a control gro up of healthy naval divers. In the second part we recorded brain MRI from t hree groups of volunteers: 1) divers who were treated for DCS in pressure c hamber, 2) divers who had never had symptoms of DCS (and/or AGE), and 3) he althy normal controls who were not divers. Our results indicate that DCS in creases the incidence of pathologic EEG recordings, whereas recompression t reatment decreases them. The results of MRI do not verify evidence of incre ased numbers of CNS lesions in normal divers as compared to non-diving, hea lthy control subjects, whereas some of the divers treated for DCS in a pres sure chamber had hyperintense lesions in brain white matter. None of them h ad any abnormalities in EEG,neurologic performance, or psychologic behavior . Both EEG and MRI are sensitive and non-specific methods for judging suspe cted evidence of brain lesions from diving or diving accidents.