Neuropsychological Evaluation of Bystander Exposure to Pesticides
By Raymond Singer, Ph.D.
October, 1999
Contents
Background: There are reports in the literature of long-term neuropsychological dysfunction in persons with pesticide exposure. However, this report presents data on exposure to a person not occupationally exposed and with sudden onset of exposure. A home with open windows and a property were sprayed by helicopter with a mixture of chlorpyrifos and a carbamate (carbofuran). Three dogs on the property, fed from separate cans of food, were vomiting and listless, and were diagnosed by their veterinarian with pesticide poisoning. The subject reported initial symptoms of anxiety, itching on face which spread over her body, dizziness and forgetfulness, with sleep frequently interrupted around 2-3 am with symptoms of breathlessness, then numb hands, feet, and feeling of "blacking out". She continued to reside in the home, during the time when the pesticides were still potent. Her primary symptoms at the time of this examination, three years later, was disabling chemical sensitivity, along with sleep apnea-like episodes, and memory problems. She was in litigation.
Methods: Physical examination which ruled out other causes of the symptoms, past medical record review, brain MRI and neuropsychological testing.
Results: Brain MRI showed diffuse scattered foci of increased signal intensity in the subcortical and periventricular white matter tracts. Organophosphate pesticides are known to cause degeneration of the myelin. From normal or better functioning pre-exposure function, declines in function included arithmetic (5%tile); digit-symbol and symbol search (9%tile); visual memory (BVRT, 11 errors); embedded figures (1%tile); paired associates learning (1%tile) and logical memory (1%tile). Personality testing showed no personality disorder.
Conclusion:Doctors need to be aware that pesticide exposure can lead to permanent neuropsychological deficits, even with a "single" exposure. Brain dysfunction from neurotoxicity cand be revealed with appropriate neuropsychological testing.
About the Author: Raymond Singer, Ph.D. is a neurotoxicologist and psychologist practicing in Santa Fe, New Mexico and New York City. His work has been presented at scientific meetings around the world, and his findings have been published in professional journals. Dr. Singer has served as an expert witness in litigation involving pesticides, herbicides, heavy metals, mixed chemical waste, and other toxic substances.
Singer, R. (1999). Journal of Neuropsychiatry and Clinical Neurosciences. Vol. 11, #1, Winter, pp. 161-162.
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