Effects of hydrogen sulfide on neurobehavioral function

Background: Nineteen hydrogen sulfide (H2S)-exposed patients were compared with 202 unexposed subjects. This 1997-to-2001 case-referent series was compared with 16 previous (1991-1996) case-referent patients. Methods: New patients were bystanders of H2S exposure and none had been unconscious. In contrast, 13 members of the prior group were exposed at work and 7 had been unconscious. The three groups were compared on the basis of 8 physiologic and 12 psychological measurements. Observed measurements were compared with predicted ones after adjusting for age, sex, educational attainment (years), and other significant factors (observed/predicted x 100). Results: The new group performed poorly compared with unexposed controls and were similar to the first group on balance, reaction time, color discrimination, visual performance, hearing, Culture Fair, digit symbol, vocabulary, verbal recall, peg placement, trail making A and B, and information. Conclusion: H2S impairments associated with H2S were similar in 19 wrkers (44% had been unconscious) and in 16 bystanders who had not been unconscious.