Chronic neurological sequelae to organophosphate pesticide poisoning.

Abstract

OBJECTIVES. This work was undertaken to determine whether there are any chronic neurological sequelae to acute organophosphate pesticide poisoning. METHODS. California surveillance data were used in a study of neurological function among 128 men poisoned by organophosphate pesticides in California from 1982 to 1990 and 90 referents. Tests included a neurological physical examination, 5 nerve conduction tests, 2 vibrotactile sensitivity tests, 10 neurobehavioral tests, and 1 postural sway test. RESULTS. After correcting for confounding, the poisoned group performed significantly worse than the referent group on two neurobehavioral tests (sustained visual attention and mood scales). When the data were restricted to men with documented cholinesterase inhibition (n = 83) or to men who had been hospitalized (n = 36), the poisoned subjects also showed significantly worse vibrotactile sensitivity of finger and toe. Significant trends of increased impairment were found with increased days of disability on a wide spectrum of tests of both central and peripheral nerve function. CONCLUSIONS. While these findings are limited by low response rates and by small sample sizes for specific pesticides, this study was based on a large surveillance database and is the largest study to date of the chronic effects of organophosphate pesticide poisoning. The evidence of some long-term effects of poisoning is consistent with two prior studies.

Low level exposures to organophosphorus esters may cause neurotoxicity

“…The study also provided important insight into the profile of neurotoxicity, which confirmed earlier findings and showed that there was a positive correlation between abnormal neurological tests and evidence of anxiety and depression in patients exposed to OP. In another study , the neuropathy profile confirmed earlier observations (Kaplan et al, 1993;Steenland et al, 1994;McConnell et al, 1994;Horowitz et al, 1999;Pilkington et al, 1999) that this neuropathy linked to LTLL exposure to OP, unlike OPIDN, was predominately involving the sensory nerve fibres and affected both small and large fibre populations. This neuropathy profile linked with LTLL exposure to OP was also compared with another one seen in chronic neurotoxicity following one or more acute cholinergic episodes ).…”

Effects of Pesticides on the Peripheral and Central Nervous System in Tobacco Farmers in Malaysia: Studies on Peripheral Nerve Conduction, Brain-Evoked Potentials and Computerized Posturography

“…Engel et al 42) observed that ulnar MCV in apple thinners who were exposed to detectable levels of organophosphorus did not significantly become slower than that in references. On the other hand, Steenland et al 27) reported significant trends of increased impairment with increased days of disability for peroneal MCV in organophosphorus poisoning cases. Ruijten et al 26) reported the relationship between organophosphorus pesticide exposure and decreasing median MCV and SCV, peroneal MCV, and Sural SCV.…”

“…slowed NCVs [25][26][27] , prolonged latencies of brain-evoked potentials 28) , and indicated abnormal pattern on postural sway assessment 29) . However, it has been unclear which of the methods is most sensitive to the effects of pesticides.…”

Adaptation of the Behavioral Assessment and Research System (BARS) for evaluating neurobehavioral performance in Filipino children

“…Organophosphate (OP) poisoned individuals have shown a consistent pattern of deficits when compared to a non-exposed or non-poisoned population on measures of motor speed and coordination, sustained attention, and information processing speed (Reidy, et al, 1992;Rosenstock, et al, 1991;Savage, et al, 1988;Steenland, et al, 1994;Wesseling, et al, 2002). Similarly, several studies have identified neurobehavioral effects in workers with longterm low-level exposure to pesticides.…”