Abstract
Hit Reaction Time latencies (HRT) in the Continuous Performance Test (CPT) measure the speed of visual information processing. The latencies may involve different neuropsychological functions depending on the time from test initiation, i.e., first orientation, learning and habituation, then cognitive processing and focused attention, and finally sustained attention as the dominant demand. Prenatal methylmercury exposure is associated with increased reaction time (RT) latencies. We therefore examined the association of methylmercury exposure with the average HRT at age 14. years at three different time intervals after test initiation. A total of 878 adolescents (87% of birth cohort members) completed the CPT. The RT latencies were recorded for 10. min, with visual targets presented at 1000. ms intervals. After confounder adjustment, regression coefficients showed that CPT-RT outcomes differed in their associations with exposure biomarkers of prenatal methylmercury exposure: During the first 2. min, the average HRT was weakly associated with methylmercury (beta (SE) for a ten-fold increase in exposure, (3.41 (2.06)), was strongly for the 3-to-6. min interval (6.10 (2.18)), and the strongest during 7-10. min after test initiation (7.64 (2.39)). This pattern was unchanged when simple reaction time and finger tapping speed were included in the models as covariates. Postnatal methylmercury exposures did not affect the outcomes. Thus, these findings suggest that sustained attention as a neuropsychological domain is particularly vulnerable to developmental methylmercury exposure, indicating probable underlying dysfunction of the frontal lobes. When using CPT data as a possible measure of neurotoxicity, test results should therefore be analyzed in regard to time from test initiation and not as overall average reaction times. © 2010 Elsevier Inc.
Original language | English |
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Pages (from-to) | 627-632 |
Number of pages | 7 |
Journal | Neurotoxicology and Teratology |
Volume | 32 |
Issue number | 6 |
Early online date | 8 Aug 2010 |
DOIs | |
Publication status | Published - Nov 2010 |
Keywords
- Attention function
- Neurotoxicity syndromes
- Prenatal exposure delayed effects
- Reaction time