Auditory event-related potential changes in chronic occupational exposure to organophosphate pesticides.
OBJECTIVE
To determine whether chronic occupational exposure to organophosphates (OP) pesticides leads to cognitive impairment using event-related potentials (ERPs).


METHODS
ERPs of 38 vegetable farmers applying OP pesticides and 35 controls were recorded using an auditory oddball paradigm. The N1, P2, N2 and P300 ERP components and the number of counting errors were compared between the groups.


RESULTS
The farmers made significantly more counting errors than controls in the oddball task. The mixed model ANOVA of component latencies revealed a significant componentxgroup interaction, suggesting farmers had a greater delay in later ERP components. Intergroup comparisons of individual components showed significant delays in N2 and P300 latencies. Subsequent ANCOVA showed significant P300 delay even after adjusting for the latency of the preceding component, N2. Intergroup differences of P300 amplitudes were not significant, although there was limited evidence of a difference in scalp topography.


CONCLUSIONS
Our findings indicate that chronic low-level occupational exposure to OP pesticides is associated with progressively increasing delay in successive ERP components, particularly P300.


CONCLUSIONS
Chronic exposure to OP pesticides may delay the neurophysiological processes underlying early stages of selective attention and late stages of sensory information processing that include stimulus evaluation and updating of working memory.
Dassanayake
T
T
Department of Physiology, Faculty of Medicine, University of Peradeniya, Peradeniya 20400, Sri Lanka. tlag23@yahoo.co.uk
Gawarammana
I B
IB
Weerasinghe
V
V
Dissanayake
P S
PS
Pragaash
S
S
Dawson
A
A
Senanayake
N
N
D000161:Acoustic Stimulation; D000383:Agriculture; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010755:Organophosphates / Q000009:adverse effects*; D010575:Pesticides / Q000009:adverse effects*; D013188:Sri Lanka; D014675:Vegetables
D010755:Organophosphates; D010575:Pesticides
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