engleski

P-300 in Evaluation of Cognitive Impairment During Chronic Organic Solvent Exposure in Humans

The organic solvent xylene is known to be a human neurotoxicant. In a group of medical workers at the Department of Pathology (4 male, 31 female, mean age 36+/-7.7 yrs), exposed to daily inhalation of xylene for at least five years, auditory event related potentials and reaction time were studied using the oddball paradigm (25% target stimuli). All subjects underwent psychological testing . Highly elevated concentrations of xylene in the working environment ranged between 1000-3000 mg/m3, although in our country threshold limit value (TLV) of xylene is 440 mg/m3 without personal protection devices. In the urine samples after the workshift the concentrations of m-methylhippuric acid, the most reliable indicator of xylene exposure, were in the range 16.32-278.75 mg/g creatinine and did not reach biological tolerance value of 1500 mg/g creatinine. The findings in exposed workers were compared to a non-exposed age-matched control group (n=21). Two kinds of auditory stimuli were presented: high (1000 Hz) and low (800 Hz) both of 50 ms duration and 80 dB intensity, interstimulus interval 3.5-5.5 ms. The P-300 mean latency in exposed workers was 378+/- 23 ms. In the non-exposed control group P-300 mean latency was 357+/-12 ms, being significantly prolonged in the group of exposed workers compared to the control group (p <0.001, ANOVA). In the exposed group mean amplitude of P-300 was significantly smaller (10.0 +/4 uV) compared to the control group (12.6 +/-4, p <0.05, ANOVA). The obtained neurophysiological data show differences in processing information between the two groups. Psychological testing did not show elements of deterioration on the applied tests. Possible long term influence on cognition of xylene exposure is discussed.

P-300; cognitive impairment; xylene; chronic solvent exposure; humans

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