Long-term use of organophosphates and neuropsychological performance

Nancy Fiedler, Howard Kipen, Kathie Kelly-McNeil, Richard Fenske

Research output: Contribution to journalArticlepeer-review

132 Scopus citations


This study evaluated neuropsychological effects due to chronic organophosphate use among farmers with no history of acute poisoning. Fifty- seven male tree fruit farmers (exposed) were compared with 42 age-matched male cranberry/blueberry growers and hardware store owners (unexposed). Univariate analyses of covariance (reading test as covariate) comparing exposed and unexposed subjects revealed significantly slower reaction time. No other significant differences were noted on tests of concentration, visuomotor skills, memory, expressive language, or mood. Based on an exposure metric derived from detailed exposure histories, farmers were divided into high exposure (n = 40) and low exposure (n = 59) groups, and their neuropsychological performance was compared. Analysis of covariance with age and reading test score as covariates revealed that the high exposure group had significantly slower reaction time, dominant hand. Long-term use of organophosphates without evidence of an acute poisoning episode appears to produce, at most, subtle changes in neuropsychological performance.

Original languageEnglish (US)
Pages (from-to)487-496
Number of pages10
JournalAmerican journal of industrial medicine
Issue number5
StatePublished - Nov 1997

All Science Journal Classification (ASJC) codes

  • Public Health, Environmental and Occupational Health


  • Exposure metric
  • Farmers
  • Neuropsychological
  • Organophosphates
  • Reaction time


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