Trans-cranial doppler and peripheral sensory threshold tests for carbon disulfide poisoning

Trans-cranial doppler (TCD) and sensory threshold (vibration, pain and discrimination) tests, which are safe and inexpensive techniques, were applied to detect cerebral vasoreactivity or neuropathic changes between carbon disulfide (CS₂) poisoning cases and two control groups respectively. The cases were 31 male CS₂ poisoning workers, and the first control group for the TCD test consisted of eight healthy men, and the second group for the threshold test were 21 healthy male workers. In the TCD test, the blood flow velocity in both middle cerebral arteries and the CO₂ content of expired air were measured to evaluate CO₂ reactivity. The vibration and pain perception threshold were measured on both the 2nd and 5th fingers. The CS₂ poisoning cases showed higher rates of abnormal CO₂ reactivity above the cut-off value than healthy controls (80.081.8% vs 0%). Among the threshold tests, the proportions of abnormal pain threshold of both the 2nd and 5th fingers were higher in poisoning cases than in the controls (77.8%-88.9% vs 11.1-33.3%) among over 45 yr old subjects. CO₂ reactivity and pain threshold test showed the possibility to detect changes in cerebral vessels and the sensory threshold in CS₂ exposure cases, but there should be further study to apply these tests to workers exposed to CS₂ before the development of CS₂ poisoning, with large number of control subjects.